Merge changes from CUPS 1.6svn-r10127.

[thirdparty/cups.git] / cups / ipp.c

/*
 * "$Id: ipp.c 10102 2011-11-02 23:52:39Z mike $"
 *
 *   Internet Printing Protocol functions for CUPS.
 *
 *   Copyright 2007-2011 by Apple Inc.
 *   Copyright 1997-2007 by Easy Software Products, all rights reserved.
 *
 *   These coded instructions, statements, and computer programs are the
 *   property of Apple Inc. and are protected by Federal copyright
 *   law.  Distribution and use rights are outlined in the file "LICENSE.txt"
 *   which should have been included with this file.  If this file is
 *   file is missing or damaged, see the license at "http://www.cups.org/".
 *
 *   This file is subject to the Apple OS-Developed Software exception.
 *
 * Contents:
 *
 *   ippAddBoolean()        - Add a boolean attribute to an IPP message.
 *   ippAddBooleans()       - Add an array of boolean values.
 *   ippAddCollection()     - Add a collection value.
 *   ippAddCollections()    - Add an array of collection values.
 *   ippAddDate()           - Add a date attribute to an IPP message.
 *   ippAddInteger()        - Add a integer attribute to an IPP message.
 *   ippAddIntegers()       - Add an array of integer values.
 *   ippAddOctetString()    - Add an octetString value to an IPP message.
 *   ippAddOutOfBand()      - Add an out-of-band value to an IPP message.
 *   ippAddRange()          - Add a range of values to an IPP message.
 *   ippAddRanges()         - Add ranges of values to an IPP message.
 *   ippAddResolution()     - Add a resolution value to an IPP message.
 *   ippAddResolutions()    - Add resolution values to an IPP message.
 *   ippAddSeparator()      - Add a group separator to an IPP message.
 *   ippAddString()         - Add a language-encoded string to an IPP message.
 *   ippAddStrings()        - Add language-encoded strings to an IPP message.
 *   ippCopyAttribute()     - Copy an attribute.
 *   ippCopyAttributes()    - Copy attributes from one IPP message to another.
 *   ippDateToTime()        - Convert from RFC 1903 Date/Time format to UNIX
 *                            time in seconds.
 *   ippDelete()            - Delete an IPP message.
 *   ippDeleteAttribute()   - Delete a single attribute in an IPP message.
 *   ippDeleteValues()      - Delete values in an attribute.
 *   ippFindAttribute()     - Find a named attribute in a request.
 *   ippFindNextAttribute() - Find the next named attribute in a request.
 *   ippFirstAttribute()    - Return the first attribute in the message.
 *   ippGetBoolean()        - Get a boolean value for an attribute.
 *   ippGetCollection()     - Get a collection value for an attribute.
 *   ippGetCount()          - Get the number of values in an attribute.
 *   ippGetDate()           - Get a date value for an attribute.
 *   ippGetGroupTag()       - Get the group associated with an attribute.
 *   ippGetInteger()        - Get the integer/enum value for an attribute.
 *   ippGetName()           - Get the attribute name.
 *   ippGetOperation()      - Get the operation ID in an IPP message.
 *   ippGetRange()          - Get a rangeOfInteger value from an attribute.
 *   ippGetRequestId()      - Get the request ID from an IPP message.
 *   ippGetResolution()     - Get a resolution value for an attribute.
 *   ippGetStatusCode()     - Get the status code from an IPP response or event
 *                            message.
 *   ippGetString()         - Get the string and optionally the language code
 *                            for an attribute.
 *   ippGetValueTag()       - Get the value tag for an attribute.
 *   ippGetVersion()        - Get the major and minor version number from an
 *                            IPP message.
 *   ippLength()            - Compute the length of an IPP message.
 *   ippNextAttribute()     - Return the next attribute in the message.
 *   ippNew()               - Allocate a new IPP message.
 *   ippNewRequest()        - Allocate a new IPP request message.
 *   ippRead()              - Read data for an IPP message from a HTTP
 *                            connection.
 *   ippReadFile()          - Read data for an IPP message from a file.
 *   ippReadIO()            - Read data for an IPP message.
 *   ippSetBoolean()        - Set a boolean value in an attribute.
 *   ippSetCollection()     - Set a collection value in an attribute.
 *   ippSetDate()           - Set a date value in an attribute.
 *   ippSetGroupTag()       - Set the group tag of an attribute.
 *   ippSetInteger()        - Set an integer or enum value in an attribute.
 *   ippSetName()           - Set the name of an attribute.
 *   ippSetOperation()      - Set the operation ID in an IPP request message.
 *   ippSetRange()          - Set a rangeOfInteger value in an attribute.
 *   ippSetRequestId()      - Set the request ID in an IPP message.
 *   ippSetResolution()     - Set a resolution value in an attribute.
 *   ippSetState()          - Set the current state of the IPP message.
 *   ippSetStatusCode()     - Set the status code in an IPP response or event
 *                            message.
 *   ippSetString()         - Set a string value in an attribute.
 *   ippSetValueTag()       - Set the value tag of an attribute.
 *   ippSetVersion()        - Set the version number in an IPP message.
 *   ippTimeToDate()        - Convert from UNIX time to RFC 1903 format.
 *   ippWrite()             - Write data for an IPP message to a HTTP
 *                            connection.
 *   ippWriteFile()         - Write data for an IPP message to a file.
 *   ippWriteIO()           - Write data for an IPP message.
 *   ipp_add_attr()         - Add a new attribute to the message.
 *   ipp_buffer_get()       - Get a read/write buffer.
 *   ipp_buffer_release()   - Release a read/write buffer.
 *   ipp_free_values()      - Free attribute values.
 *   ipp_get_code()         - Convert a C locale/charset name into an IPP
 *                            language/charset code.
 *   ipp_lang_code()        - Convert a C locale name into an IPP language
 *                            code.
 *   ipp_length()           - Compute the length of an IPP message or
 *                            collection value.
 *   ipp_read_http()        - Semi-blocking read on a HTTP connection...
 *   ipp_read_file()        - Read IPP data from a file.
 *   ipp_set_value()        - Get the value element from an attribute,
 *                            expanding it as needed.
 *   ipp_write_file()       - Write IPP data to a file.
 */

/*
 * Include necessary headers...
 */

#include "cups-private.h"
#ifdef WIN32
#  include <io.h>
#endif /* WIN32 */


/*
 * Local functions...
 */

static ipp_attribute_t  *ipp_add_attr(ipp_t *ipp, const char *name, ipp_tag_t  group_tag,
                                      ipp_tag_t value_tag, int num_values);
static unsigned char    *ipp_buffer_get(void);
static void             ipp_buffer_release(unsigned char *b);
static void             ipp_free_values(ipp_attribute_t *attr, int element, int count);
static char             *ipp_get_code(const char *locale, char *buffer, size_t bufsize);
static char             *ipp_lang_code(const char *locale, char *buffer, size_t bufsize);
static size_t           ipp_length(ipp_t *ipp, int collection);
static ssize_t          ipp_read_http(http_t *http, ipp_uchar_t *buffer,
                                      size_t length);
static ssize_t          ipp_read_file(int *fd, ipp_uchar_t *buffer,
                                      size_t length);
static _ipp_value_t     *ipp_set_value(ipp_t *ipp, ipp_attribute_t **attr, int element);
static ssize_t          ipp_write_file(int *fd, ipp_uchar_t *buffer,
                                       size_t length);


/*
 * 'ippAddBoolean()' - Add a boolean attribute to an IPP message.
 *
 * The @code ipp@ parameter refers to an IPP message previously created using the
 * @link ippNew@ or @link ippNewRequest@ functions.
 *
 * The @code group@ parameter specifies the IPP attribute group tag: none
 * (@code IPP_TAG_ZERO@, for member attributes), document (@code IPP_TAG_DOCUMENT@),
 * event notification (@code IPP_TAG_EVENT_NOTIFICATION@), operation
 * (@code IPP_TAG_OPERATION@), printer (@code IPP_TAG_PRINTER@), subscription
 * (@code IPP_TAG_SUBSCRIPTION@), or unsupported (@code IPP_TAG_UNSUPPORTED_GROUP@).
 */

ipp_attribute_t *                       /* O - New attribute */
ippAddBoolean(ipp_t      *ipp,          /* I - IPP message */
              ipp_tag_t  group,         /* I - IPP group */
              const char *name,         /* I - Name of attribute */
              char       value)         /* I - Value of attribute */
{
  ipp_attribute_t       *attr;          /* New attribute */


  DEBUG_printf(("ippAddBoolean(ipp=%p, group=%02x(%s), name=\"%s\", value=%d)",
                ipp, group, ippTagString(group), name, value));

 /*
  * Range check input...
  */

  if (!ipp || !name || group < IPP_TAG_ZERO ||
      group == IPP_TAG_END || group >= IPP_TAG_UNSUPPORTED_VALUE)
    return (NULL);

 /*
  * Create the attribute...
  */

  if ((attr = ipp_add_attr(ipp, name, group, IPP_TAG_BOOLEAN, 1)) == NULL)
    return (NULL);

  attr->values[0].boolean = value;

  return (attr);
}


/*
 * 'ippAddBooleans()' - Add an array of boolean values.
 *
 * The @code ipp@ parameter refers to an IPP message previously created using the
 * @link ippNew@ or @link ippNewRequest@ functions.
 *
 * The @code group@ parameter specifies the IPP attribute group tag: none
 * (@code IPP_TAG_ZERO@, for member attributes), document (@code IPP_TAG_DOCUMENT@),
 * event notification (@code IPP_TAG_EVENT_NOTIFICATION@), operation
 * (@code IPP_TAG_OPERATION@), printer (@code IPP_TAG_PRINTER@), subscription
 * (@code IPP_TAG_SUBSCRIPTION@), or unsupported (@code IPP_TAG_UNSUPPORTED_GROUP@).
 */

ipp_attribute_t *                       /* O - New attribute */
ippAddBooleans(ipp_t      *ipp,         /* I - IPP message */
               ipp_tag_t  group,        /* I - IPP group */
               const char *name,        /* I - Name of attribute */
               int        num_values,   /* I - Number of values */
               const char *values)      /* I - Values */
{
  int                   i;              /* Looping var */
  ipp_attribute_t       *attr;          /* New attribute */
  _ipp_value_t          *value;         /* Current value */


  DEBUG_printf(("ippAddBooleans(ipp=%p, group=%02x(%s), name=\"%s\", "
                "num_values=%d, values=%p)", ipp, group, ippTagString(group),
                name, num_values, values));

 /*
  * Range check input...
  */

  if (!ipp || !name || group < IPP_TAG_ZERO ||
      group == IPP_TAG_END || group >= IPP_TAG_UNSUPPORTED_VALUE ||
      num_values < 1)
    return (NULL);

 /*
  * Create the attribute...
  */

  if ((attr = ipp_add_attr(ipp, name, group, IPP_TAG_BOOLEAN, num_values)) == NULL)
    return (NULL);

  if (values)
  {
    for (i = num_values, value = attr->values;
         i > 0;
         i --, value ++)
      value->boolean = *values++;
  }

  return (attr);
}


/*
 * 'ippAddCollection()' - Add a collection value.
 *
 * The @code ipp@ parameter refers to an IPP message previously created using the
 * @link ippNew@ or @link ippNewRequest@ functions.
 *
 * The @code group@ parameter specifies the IPP attribute group tag: none
 * (@code IPP_TAG_ZERO@, for member attributes), document (@code IPP_TAG_DOCUMENT@),
 * event notification (@code IPP_TAG_EVENT_NOTIFICATION@), operation
 * (@code IPP_TAG_OPERATION@), printer (@code IPP_TAG_PRINTER@), subscription
 * (@code IPP_TAG_SUBSCRIPTION@), or unsupported (@code IPP_TAG_UNSUPPORTED_GROUP@).
 *
 * @since CUPS 1.1.19/Mac OS X 10.3@
 */

ipp_attribute_t *                       /* O - New attribute */
ippAddCollection(ipp_t      *ipp,       /* I - IPP message */
                 ipp_tag_t  group,      /* I - IPP group */
                 const char *name,      /* I - Name of attribute */
                 ipp_t      *value)     /* I - Value */
{
  ipp_attribute_t       *attr;          /* New attribute */


  DEBUG_printf(("ippAddCollection(ipp=%p, group=%02x(%s), name=\"%s\", "
                "value=%p)", ipp, group, ippTagString(group), name, value));

 /*
  * Range check input...
  */

  if (!ipp || !name || group < IPP_TAG_ZERO ||
      group == IPP_TAG_END || group >= IPP_TAG_UNSUPPORTED_VALUE)
    return (NULL);

 /*
  * Create the attribute...
  */

  if ((attr = ipp_add_attr(ipp, name, group, IPP_TAG_BEGIN_COLLECTION, 1)) == NULL)
    return (NULL);

  attr->values[0].collection = value;

  if (value)
    value->use ++;

  return (attr);
}


/*
 * 'ippAddCollections()' - Add an array of collection values.
 *
 * The @code ipp@ parameter refers to an IPP message previously created using the
 * @link ippNew@ or @link ippNewRequest@ functions.
 *
 * The @code group@ parameter specifies the IPP attribute group tag: none
 * (@code IPP_TAG_ZERO@, for member attributes), document (@code IPP_TAG_DOCUMENT@),
 * event notification (@code IPP_TAG_EVENT_NOTIFICATION@), operation
 * (@code IPP_TAG_OPERATION@), printer (@code IPP_TAG_PRINTER@), subscription
 * (@code IPP_TAG_SUBSCRIPTION@), or unsupported (@code IPP_TAG_UNSUPPORTED_GROUP@).
 *
 * @since CUPS 1.1.19/Mac OS X 10.3@
 */

ipp_attribute_t *                       /* O - New attribute */
ippAddCollections(
    ipp_t       *ipp,                   /* I - IPP message */
    ipp_tag_t   group,                  /* I - IPP group */
    const char  *name,                  /* I - Name of attribute */
    int         num_values,             /* I - Number of values */
    const ipp_t **values)               /* I - Values */
{
  int                   i;              /* Looping var */
  ipp_attribute_t       *attr;          /* New attribute */
  _ipp_value_t          *value;         /* Current value */


  DEBUG_printf(("ippAddCollections(ipp=%p, group=%02x(%s), name=\"%s\", "
                "num_values=%d, values=%p)", ipp, group, ippTagString(group),
                name, num_values, values));

 /*
  * Range check input...
  */

  if (!ipp || !name || group < IPP_TAG_ZERO ||
      group == IPP_TAG_END || group >= IPP_TAG_UNSUPPORTED_VALUE ||
      num_values < 1)
    return (NULL);

 /*
  * Create the attribute...
  */

  if ((attr = ipp_add_attr(ipp, name, group, IPP_TAG_BEGIN_COLLECTION,
                           num_values)) == NULL)
    return (NULL);

  if (values)
  {
    for (i = num_values, value = attr->values;
         i > 0;
         i --, value ++)
    {
      value->collection = (ipp_t *)*values++;
      value->collection->use ++;
    }
  }

  return (attr);
}


/*
 * 'ippAddDate()' - Add a date attribute to an IPP message.
 *
 * The @code ipp@ parameter refers to an IPP message previously created using the
 * @link ippNew@ or @link ippNewRequest@ functions.
 *
 * The @code group@ parameter specifies the IPP attribute group tag: none
 * (@code IPP_TAG_ZERO@, for member attributes), document (@code IPP_TAG_DOCUMENT@),
 * event notification (@code IPP_TAG_EVENT_NOTIFICATION@), operation
 * (@code IPP_TAG_OPERATION@), printer (@code IPP_TAG_PRINTER@), subscription
 * (@code IPP_TAG_SUBSCRIPTION@), or unsupported (@code IPP_TAG_UNSUPPORTED_GROUP@).
 */

ipp_attribute_t *                       /* O - New attribute */
ippAddDate(ipp_t             *ipp,      /* I - IPP message */
           ipp_tag_t         group,     /* I - IPP group */
           const char        *name,     /* I - Name of attribute */
           const ipp_uchar_t *value)    /* I - Value */
{
  ipp_attribute_t       *attr;          /* New attribute */


  DEBUG_printf(("ippAddDate(ipp=%p, group=%02x(%s), name=\"%s\", value=%p)",
                ipp, group, ippTagString(group), name, value));

 /*
  * Range check input...
  */

  if (!ipp || !name || !value || group < IPP_TAG_ZERO ||
      group == IPP_TAG_END || group >= IPP_TAG_UNSUPPORTED_VALUE)
    return (NULL);

 /*
  * Create the attribute...
  */

  if ((attr = ipp_add_attr(ipp, name, group, IPP_TAG_DATE, 1)) == NULL)
    return (NULL);

  memcpy(attr->values[0].date, value, 11);

  return (attr);
}


/*
 * 'ippAddInteger()' - Add a integer attribute to an IPP message.
 *
 * The @code ipp@ parameter refers to an IPP message previously created using the
 * @link ippNew@ or @link ippNewRequest@ functions.
 *
 * The @code group@ parameter specifies the IPP attribute group tag: none
 * (@code IPP_TAG_ZERO@, for member attributes), document (@code IPP_TAG_DOCUMENT@),
 * event notification (@code IPP_TAG_EVENT_NOTIFICATION@), operation
 * (@code IPP_TAG_OPERATION@), printer (@code IPP_TAG_PRINTER@), subscription
 * (@code IPP_TAG_SUBSCRIPTION@), or unsupported (@code IPP_TAG_UNSUPPORTED_GROUP@).
 *
 * Supported values include enum (@code IPP_TAG_ENUM@) and integer
 * (@code IPP_TAG_INTEGER@).
 */

ipp_attribute_t *                       /* O - New attribute */
ippAddInteger(ipp_t      *ipp,          /* I - IPP message */
              ipp_tag_t  group,         /* I - IPP group */
              ipp_tag_t  value_tag,     /* I - Type of attribute */
              const char *name,         /* I - Name of attribute */
              int        value)         /* I - Value of attribute */
{
  ipp_attribute_t       *attr;          /* New attribute */


  DEBUG_printf(("ippAddInteger(ipp=%p, group=%02x(%s), type=%02x(%s), "
                "name=\"%s\", value=%d)", ipp, group, ippTagString(group),
                value_tag, ippTagString(value_tag), name, value));

  value_tag &= IPP_TAG_MASK;

 /*
  * Special-case for legacy usage: map out-of-band attributes to new ippAddOutOfBand
  * function...
  */

  if (value_tag >= IPP_TAG_UNSUPPORTED_VALUE && value_tag <= IPP_TAG_ADMINDEFINE)
    return (ippAddOutOfBand(ipp, group, value_tag, name));

 /*
  * Range check input...
  */

#if 0
  if (!ipp || !name || group < IPP_TAG_ZERO ||
      group == IPP_TAG_END || group >= IPP_TAG_UNSUPPORTED_VALUE ||
      (value_tag != IPP_TAG_INTEGER && value_tag != IPP_TAG_ENUM))
    return (NULL);
#else
  if (!ipp || !name || group < IPP_TAG_ZERO ||
      group == IPP_TAG_END || group >= IPP_TAG_UNSUPPORTED_VALUE)
    return (NULL);
#endif /* 0 */

 /*
  * Create the attribute...
  */

  if ((attr = ipp_add_attr(ipp, name, group, value_tag, 1)) == NULL)
    return (NULL);

  attr->values[0].integer = value;

  return (attr);
}


/*
 * 'ippAddIntegers()' - Add an array of integer values.
 *
 * The @code ipp@ parameter refers to an IPP message previously created using the
 * @link ippNew@ or @link ippNewRequest@ functions.
 *
 * The @code group@ parameter specifies the IPP attribute group tag: none
 * (@code IPP_TAG_ZERO@, for member attributes), document (@code IPP_TAG_DOCUMENT@),
 * event notification (@code IPP_TAG_EVENT_NOTIFICATION@), operation
 * (@code IPP_TAG_OPERATION@), printer (@code IPP_TAG_PRINTER@), subscription
 * (@code IPP_TAG_SUBSCRIPTION@), or unsupported (@code IPP_TAG_UNSUPPORTED_GROUP@).
 *
 * Supported values include enum (@code IPP_TAG_ENUM@) and integer
 * (@code IPP_TAG_INTEGER@).
 */

ipp_attribute_t *                       /* O - New attribute */
ippAddIntegers(ipp_t      *ipp,         /* I - IPP message */
               ipp_tag_t  group,        /* I - IPP group */
               ipp_tag_t  value_tag,    /* I - Type of attribute */
               const char *name,        /* I - Name of attribute */
               int        num_values,   /* I - Number of values */
               const int  *values)      /* I - Values */
{
  int                   i;              /* Looping var */
  ipp_attribute_t       *attr;          /* New attribute */
  _ipp_value_t          *value;         /* Current value */


  DEBUG_printf(("ippAddIntegers(ipp=%p, group=%02x(%s), type=%02x(%s), "
                "name=\"%s\", num_values=%d, values=%p)", ipp,
                group, ippTagString(group), value_tag, ippTagString(value_tag), name,
                num_values, values));

  value_tag &= IPP_TAG_MASK;

 /*
  * Range check input...
  */

#if 0
  if (!ipp || !name || group < IPP_TAG_ZERO ||
      group == IPP_TAG_END || group >= IPP_TAG_UNSUPPORTED_VALUE ||
      (value_tag != IPP_TAG_INTEGER && value_tag != IPP_TAG_ENUM) ||
      num_values < 1)
    return (NULL);
#else
  if (!ipp || !name || group < IPP_TAG_ZERO ||
      group == IPP_TAG_END || group >= IPP_TAG_UNSUPPORTED_VALUE ||
      num_values < 1)
    return (NULL);
#endif /* 0 */

 /*
  * Create the attribute...
  */

  if ((attr = ipp_add_attr(ipp, name, group, value_tag, num_values)) == NULL)
    return (NULL);

  if (values)
  {
    for (i = num_values, value = attr->values;
         i > 0;
         i --, value ++)
      value->integer = *values++;
  }

  return (attr);
}


/*
 * 'ippAddOctetString()' - Add an octetString value to an IPP message.
 *
 * The @code ipp@ parameter refers to an IPP message previously created using the
 * @link ippNew@ or @link ippNewRequest@ functions.
 *
 * The @code group@ parameter specifies the IPP attribute group tag: none
 * (@code IPP_TAG_ZERO@, for member attributes), document (@code IPP_TAG_DOCUMENT@),
 * event notification (@code IPP_TAG_EVENT_NOTIFICATION@), operation
 * (@code IPP_TAG_OPERATION@), printer (@code IPP_TAG_PRINTER@), subscription
 * (@code IPP_TAG_SUBSCRIPTION@), or unsupported (@code IPP_TAG_UNSUPPORTED_GROUP@).
 *
 * @since CUPS 1.2/Mac OS X 10.5@
 */

ipp_attribute_t *                       /* O - New attribute */
ippAddOctetString(ipp_t      *ipp,      /* I - IPP message */
                  ipp_tag_t  group,     /* I - IPP group */
                  const char *name,     /* I - Name of attribute */
                  const void *data,     /* I - octetString data */
                  int        datalen)   /* I - Length of data in bytes */
{
  ipp_attribute_t       *attr;          /* New attribute */


  if (!ipp || !name || group < IPP_TAG_ZERO ||
      group == IPP_TAG_END || group >= IPP_TAG_UNSUPPORTED_VALUE)
    return (NULL);

  if ((attr = ipp_add_attr(ipp, name, group, IPP_TAG_STRING, 1)) == NULL)
    return (NULL);

 /*
  * Initialize the attribute data...
  */

  attr->values[0].unknown.length = datalen;

  if (data)
  {
    if ((attr->values[0].unknown.data = malloc(datalen)) == NULL)
    {
      ippDeleteAttribute(ipp, attr);
      return (NULL);
    }

    memcpy(attr->values[0].unknown.data, data, datalen);
  }

 /*
  * Return the new attribute...
  */

  return (attr);
}


/*
 * 'ippAddOutOfBand()' - Add an out-of-band value to an IPP message.
 *
 * The @code ipp@ parameter refers to an IPP message previously created using the
 * @link ippNew@ or @link ippNewRequest@ functions.
 *
 * The @code group@ parameter specifies the IPP attribute group tag: none
 * (@code IPP_TAG_ZERO@, for member attributes), document (@code IPP_TAG_DOCUMENT@),
 * event notification (@code IPP_TAG_EVENT_NOTIFICATION@), operation
 * (@code IPP_TAG_OPERATION@), printer (@code IPP_TAG_PRINTER@), subscription
 * (@code IPP_TAG_SUBSCRIPTION@), or unsupported (@code IPP_TAG_UNSUPPORTED_GROUP@).
 *
 * Supported out-of-band values include unsupported-value
 * (@code IPP_TAG_UNSUPPORTED_VALUE@), default (@code IPP_TAG_DEFAULT@), unknown
 * (@code IPP_TAG_UNKNOWN@), no-value (@code IPP_TAG_NOVALUE@), not-settable
 * (@code IPP_TAG_NOTSETTABLE@), delete-attribute (@code IPP_TAG_DELETEATTR@), and
 * admin-define (@code IPP_TAG_ADMINDEFINE@).
 *
 * @since CUPS 1.6@
 */

ipp_attribute_t *                       /* O - New attribute */
ippAddOutOfBand(ipp_t      *ipp,        /* I - IPP message */
                ipp_tag_t  group,       /* I - IPP group */
                ipp_tag_t  value_tag,   /* I - Type of attribute */
                const char *name)       /* I - Name of attribute */
{
  DEBUG_printf(("ippAddOutOfBand(ipp=%p, group=%02x(%s), value_tag=%02x(%s), "
                "name=\"%s\")", ipp, group, ippTagString(group), value_tag,
                ippTagString(value_tag), name));

  value_tag &= IPP_TAG_MASK;

 /*
  * Range check input...
  */

  if (!ipp || !name || group < IPP_TAG_ZERO ||
      group == IPP_TAG_END || group >= IPP_TAG_UNSUPPORTED_VALUE ||
      (value_tag != IPP_TAG_UNSUPPORTED_VALUE &&
       value_tag != IPP_TAG_DEFAULT &&
       value_tag != IPP_TAG_UNKNOWN &&
       value_tag != IPP_TAG_NOVALUE &&
       value_tag != IPP_TAG_NOTSETTABLE &&
       value_tag != IPP_TAG_DELETEATTR &&
       value_tag != IPP_TAG_ADMINDEFINE))
    return (NULL);

 /*
  * Create the attribute...
  */

  return (ipp_add_attr(ipp, name, group, value_tag, 1));
}


/*
 * 'ippAddRange()' - Add a range of values to an IPP message.
 *
 * The @code ipp@ parameter refers to an IPP message previously created using the
 * @link ippNew@ or @link ippNewRequest@ functions.
 *
 * The @code group@ parameter specifies the IPP attribute group tag: none
 * (@code IPP_TAG_ZERO@, for member attributes), document (@code IPP_TAG_DOCUMENT@),
 * event notification (@code IPP_TAG_EVENT_NOTIFICATION@), operation
 * (@code IPP_TAG_OPERATION@), printer (@code IPP_TAG_PRINTER@), subscription
 * (@code IPP_TAG_SUBSCRIPTION@), or unsupported (@code IPP_TAG_UNSUPPORTED_GROUP@).
 *
 * The @code lower@ parameter must be less than or equal to the @code upper@ parameter.
 */

ipp_attribute_t *                       /* O - New attribute */
ippAddRange(ipp_t      *ipp,            /* I - IPP message */
            ipp_tag_t  group,           /* I - IPP group */
            const char *name,           /* I - Name of attribute */
            int        lower,           /* I - Lower value */
            int        upper)           /* I - Upper value */
{
  ipp_attribute_t       *attr;          /* New attribute */


  DEBUG_printf(("ippAddRange(ipp=%p, group=%02x(%s), name=\"%s\", lower=%d, "
                "upper=%d)", ipp, group, ippTagString(group), name, lower,
                upper));

 /*
  * Range check input...
  */

  if (!ipp || !name || group < IPP_TAG_ZERO ||
      group == IPP_TAG_END || group >= IPP_TAG_UNSUPPORTED_VALUE)
    return (NULL);

 /*
  * Create the attribute...
  */

  if ((attr = ipp_add_attr(ipp, name, group, IPP_TAG_RANGE, 1)) == NULL)
    return (NULL);

  attr->values[0].range.lower = lower;
  attr->values[0].range.upper = upper;

  return (attr);
}


/*
 * 'ippAddRanges()' - Add ranges of values to an IPP message.
 *
 * The @code ipp@ parameter refers to an IPP message previously created using the
 * @link ippNew@ or @link ippNewRequest@ functions.
 *
 * The @code group@ parameter specifies the IPP attribute group tag: none
 * (@code IPP_TAG_ZERO@, for member attributes), document (@code IPP_TAG_DOCUMENT@),
 * event notification (@code IPP_TAG_EVENT_NOTIFICATION@), operation
 * (@code IPP_TAG_OPERATION@), printer (@code IPP_TAG_PRINTER@), subscription
 * (@code IPP_TAG_SUBSCRIPTION@), or unsupported (@code IPP_TAG_UNSUPPORTED_GROUP@).
 */

ipp_attribute_t *                       /* O - New attribute */
ippAddRanges(ipp_t      *ipp,           /* I - IPP message */
             ipp_tag_t  group,          /* I - IPP group */
             const char *name,          /* I - Name of attribute */
             int        num_values,     /* I - Number of values */
             const int  *lower,         /* I - Lower values */
             const int  *upper)         /* I - Upper values */
{
  int                   i;              /* Looping var */
  ipp_attribute_t       *attr;          /* New attribute */
  _ipp_value_t          *value;         /* Current value */


  DEBUG_printf(("ippAddRanges(ipp=%p, group=%02x(%s), name=\"%s\", "
                "num_values=%d, lower=%p, upper=%p)", ipp, group,
                ippTagString(group), name, num_values, lower, upper));

 /*
  * Range check input...
  */

  if (!ipp || !name || group < IPP_TAG_ZERO ||
      group == IPP_TAG_END || group >= IPP_TAG_UNSUPPORTED_VALUE ||
      num_values < 1)
    return (NULL);

 /*
  * Create the attribute...
  */

  if ((attr = ipp_add_attr(ipp, name, group, IPP_TAG_RANGE, num_values)) == NULL)
    return (NULL);

  if (lower && upper)
  {
    for (i = num_values, value = attr->values;
         i > 0;
         i --, value ++)
    {
      value->range.lower = *lower++;
      value->range.upper = *upper++;
    }
  }

  return (attr);
}


/*
 * 'ippAddResolution()' - Add a resolution value to an IPP message.
 *
 * The @code ipp@ parameter refers to an IPP message previously created using the
 * @link ippNew@ or @link ippNewRequest@ functions.
 *
 * The @code group@ parameter specifies the IPP attribute group tag: none
 * (@code IPP_TAG_ZERO@, for member attributes), document (@code IPP_TAG_DOCUMENT@),
 * event notification (@code IPP_TAG_EVENT_NOTIFICATION@), operation
 * (@code IPP_TAG_OPERATION@), printer (@code IPP_TAG_PRINTER@), subscription
 * (@code IPP_TAG_SUBSCRIPTION@), or unsupported (@code IPP_TAG_UNSUPPORTED_GROUP@).
 */

ipp_attribute_t *                       /* O - New attribute */
ippAddResolution(ipp_t      *ipp,       /* I - IPP message */
                 ipp_tag_t  group,      /* I - IPP group */
                 const char *name,      /* I - Name of attribute */
                 ipp_res_t  units,      /* I - Units for resolution */
                 int        xres,       /* I - X resolution */
                 int        yres)       /* I - Y resolution */
{
  ipp_attribute_t       *attr;          /* New attribute */


  DEBUG_printf(("ippAddResolution(ipp=%p, group=%02x(%s), name=\"%s\", "
                "units=%d, xres=%d, yres=%d)", ipp, group,
                ippTagString(group), name, units, xres, yres));

 /*
  * Range check input...
  */

  if (!ipp || !name || group < IPP_TAG_ZERO ||
      group == IPP_TAG_END || group >= IPP_TAG_UNSUPPORTED_VALUE ||
      units < IPP_RES_PER_INCH || units > IPP_RES_PER_CM ||
      xres < 0 || yres < 0)
    return (NULL);

 /*
  * Create the attribute...
  */

  if ((attr = ipp_add_attr(ipp, name, group, IPP_TAG_RESOLUTION, 1)) == NULL)
    return (NULL);

  attr->values[0].resolution.xres  = xres;
  attr->values[0].resolution.yres  = yres;
  attr->values[0].resolution.units = units;

  return (attr);
}


/*
 * 'ippAddResolutions()' - Add resolution values to an IPP message.
 *
 * The @code ipp@ parameter refers to an IPP message previously created using the
 * @link ippNew@ or @link ippNewRequest@ functions.
 *
 * The @code group@ parameter specifies the IPP attribute group tag: none
 * (@code IPP_TAG_ZERO@, for member attributes), document (@code IPP_TAG_DOCUMENT@),
 * event notification (@code IPP_TAG_EVENT_NOTIFICATION@), operation
 * (@code IPP_TAG_OPERATION@), printer (@code IPP_TAG_PRINTER@), subscription
 * (@code IPP_TAG_SUBSCRIPTION@), or unsupported (@code IPP_TAG_UNSUPPORTED_GROUP@).
 */

ipp_attribute_t *                       /* O - New attribute */
ippAddResolutions(ipp_t      *ipp,      /* I - IPP message */
                  ipp_tag_t  group,     /* I - IPP group */
                  const char *name,     /* I - Name of attribute */
                  int        num_values,/* I - Number of values */
                  ipp_res_t  units,     /* I - Units for resolution */
                  const int  *xres,     /* I - X resolutions */
                  const int  *yres)     /* I - Y resolutions */
{
  int                   i;              /* Looping var */
  ipp_attribute_t       *attr;          /* New attribute */
  _ipp_value_t          *value;         /* Current value */


  DEBUG_printf(("ippAddResolutions(ipp=%p, group=%02x(%s), name=\"%s\", "
                "num_value=%d, units=%d, xres=%p, yres=%p)", ipp, group,
                ippTagString(group), name, num_values, units, xres, yres));

 /*
  * Range check input...
  */

  if (!ipp || !name || group < IPP_TAG_ZERO ||
      group == IPP_TAG_END || group >= IPP_TAG_UNSUPPORTED_VALUE ||
      num_values < 1 ||
      units < IPP_RES_PER_INCH || units > IPP_RES_PER_CM)
    return (NULL);

 /*
  * Create the attribute...
  */

  if ((attr = ipp_add_attr(ipp, name, group, IPP_TAG_RESOLUTION, num_values)) == NULL)
    return (NULL);

  if (xres && yres)
  {
    for (i = num_values, value = attr->values;
         i > 0;
         i --, value ++)
    {
      value->resolution.xres  = *xres++;
      value->resolution.yres  = *yres++;
      value->resolution.units = units;
    }
  }

  return (attr);
}


/*
 * 'ippAddSeparator()' - Add a group separator to an IPP message.
 *
 * The @code ipp@ parameter refers to an IPP message previously created using the
 * @link ippNew@ or @link ippNewRequest@ functions.
 */

ipp_attribute_t *                       /* O - New attribute */
ippAddSeparator(ipp_t *ipp)             /* I - IPP message */
{
  DEBUG_printf(("ippAddSeparator(ipp=%p)", ipp));

 /*
  * Range check input...
  */

  if (!ipp)
    return (NULL);

 /*
  * Create the attribute...
  */

  return (ipp_add_attr(ipp, NULL, IPP_TAG_ZERO, IPP_TAG_ZERO, 0));
}


/*
 * 'ippAddString()' - Add a language-encoded string to an IPP message.
 *
 * The @code ipp@ parameter refers to an IPP message previously created using the
 * @link ippNew@ or @link ippNewRequest@ functions.
 *
 * The @code group@ parameter specifies the IPP attribute group tag: none
 * (@code IPP_TAG_ZERO@, for member attributes), document (@code IPP_TAG_DOCUMENT@),
 * event notification (@code IPP_TAG_EVENT_NOTIFICATION@), operation
 * (@code IPP_TAG_OPERATION@), printer (@code IPP_TAG_PRINTER@), subscription
 * (@code IPP_TAG_SUBSCRIPTION@), or unsupported (@code IPP_TAG_UNSUPPORTED_GROUP@).
 *
 * Supported string values include charset (@code IPP_TAG_CHARSET@), keyword
 * (@code IPP_TAG_KEYWORD@), language (@code IPP_TAG_LANGUAGE@), mimeMediaType
 * (@code IPP_TAG_MIMETYPE@), name (@code IPP_TAG_NAME@), nameWithLanguage
 * (@code IPP_TAG_NAMELANG), text (@code IPP_TAG_TEXT@), textWithLanguage
 * (@code IPP_TAG_TEXTLANG@), uri (@code IPP_TAG_URI@), and uriScheme
 * (@code IPP_TAG_URISCHEME@).
 *
 * The @code language@ parameter must be non-@code NULL@ for nameWithLanguage and
 * textWithLanguage string values and must be @code NULL@ for all other string values.
 */

ipp_attribute_t *                       /* O - New attribute */
ippAddString(ipp_t      *ipp,           /* I - IPP message */
             ipp_tag_t  group,          /* I - IPP group */
             ipp_tag_t  value_tag,      /* I - Type of attribute */
             const char *name,          /* I - Name of attribute */
             const char *language,      /* I - Language code */
             const char *value)         /* I - Value */
{
  ipp_tag_t             temp_tag;       /* Temporary value tag (masked) */
  ipp_attribute_t       *attr;          /* New attribute */
  char                  code[32];       /* Charset/language code buffer */


  DEBUG_printf(("ippAddString(ipp=%p, group=%02x(%s), value_tag=%02x(%s), "
                "name=\"%s\", language=\"%s\", value=\"%s\")", ipp,
                group, ippTagString(group), value_tag, ippTagString(value_tag), name,
                language, value));

 /*
  * Range check input...
  */

  temp_tag = (ipp_tag_t)((int)value_tag & IPP_TAG_MASK);

#if 0
  if (!ipp || !name || group < IPP_TAG_ZERO ||
      group == IPP_TAG_END || group >= IPP_TAG_UNSUPPORTED_VALUE ||
      (temp_tag < IPP_TAG_TEXT && temp_tag != IPP_TAG_TEXTLANG &&
       temp_tag != IPP_TAG_NAMELANG) || temp_tag > IPP_TAG_MIMETYPE)
    return (NULL);

  if ((temp_tag == IPP_TAG_TEXTLANG || temp_tag == IPP_TAG_NAMELANG)
          != (language != NULL))
    return (NULL);
#else
  if (!ipp || !name || group < IPP_TAG_ZERO ||
      group == IPP_TAG_END || group >= IPP_TAG_UNSUPPORTED_VALUE)
    return (NULL);
#endif /* 0 */

 /*
  * See if we need to map charset, language, or locale values...
  */

  if (language && ((int)value_tag & IPP_TAG_COPY) &&
      strcmp(language, ipp_lang_code(language, code, sizeof(code))))
    value_tag = temp_tag;               /* Don't do a fast copy */
  else if (value && value_tag == (ipp_tag_t)(IPP_TAG_CHARSET | IPP_TAG_COPY) &&
           strcmp(value, ipp_get_code(value, code, sizeof(code))))
    value_tag = temp_tag;               /* Don't do a fast copy */
  else if (value && value_tag == (ipp_tag_t)(IPP_TAG_LANGUAGE | IPP_TAG_COPY) &&
           strcmp(value, ipp_lang_code(value, code, sizeof(code))))
    value_tag = temp_tag;               /* Don't do a fast copy */

 /*
  * Create the attribute...
  */

  if ((attr = ipp_add_attr(ipp, name, group, value_tag, 1)) == NULL)
    return (NULL);

 /*
  * Initialize the attribute data...
  */

  if ((int)value_tag & IPP_TAG_COPY)
  {
    attr->values[0].string.language = (char *)language;
    attr->values[0].string.text     = (char *)value;
  }
  else
  {
    if (language)
      attr->values[0].string.language = _cupsStrAlloc(ipp_lang_code(language, code,
                                                      sizeof(code)));

    if (value_tag == IPP_TAG_CHARSET)
      attr->values[0].string.text = _cupsStrAlloc(ipp_get_code(value, code,
                                                               sizeof(code)));
    else if (value_tag == IPP_TAG_LANGUAGE)
      attr->values[0].string.text = _cupsStrAlloc(ipp_lang_code(value, code,
                                                                sizeof(code)));
    else
      attr->values[0].string.text = _cupsStrAlloc(value);
  }

  return (attr);
}


/*
 * 'ippAddStrings()' - Add language-encoded strings to an IPP message.
 *
 * The @code ipp@ parameter refers to an IPP message previously created using the
 * @link ippNew@ or @link ippNewRequest@ functions.
 *
 * The @code group@ parameter specifies the IPP attribute group tag: none
 * (@code IPP_TAG_ZERO@, for member attributes), document (@code IPP_TAG_DOCUMENT@),
 * event notification (@code IPP_TAG_EVENT_NOTIFICATION@), operation
 * (@code IPP_TAG_OPERATION@), printer (@code IPP_TAG_PRINTER@), subscription
 * (@code IPP_TAG_SUBSCRIPTION@), or unsupported (@code IPP_TAG_UNSUPPORTED_GROUP@).
 *
 * Supported string values include charset (@code IPP_TAG_CHARSET@), keyword
 * (@code IPP_TAG_KEYWORD@), language (@code IPP_TAG_LANGUAGE@), mimeMediaType
 * (@code IPP_TAG_MIMETYPE@), name (@code IPP_TAG_NAME@), nameWithLanguage
 * (@code IPP_TAG_NAMELANG), text (@code IPP_TAG_TEXT@), textWithLanguage
 * (@code IPP_TAG_TEXTLANG@), uri (@code IPP_TAG_URI@), and uriScheme
 * (@code IPP_TAG_URISCHEME@).
 *
 * The @code language@ parameter must be non-@code NULL@ for nameWithLanguage and
 * textWithLanguage string values and must be @code NULL@ for all other string values.
 */

ipp_attribute_t *                       /* O - New attribute */
ippAddStrings(
    ipp_t              *ipp,            /* I - IPP message */
    ipp_tag_t          group,           /* I - IPP group */
    ipp_tag_t          value_tag,       /* I - Type of attribute */
    const char         *name,           /* I - Name of attribute */
    int                num_values,      /* I - Number of values */
    const char         *language,       /* I - Language code (@code NULL@ for default) */
    const char * const *values)         /* I - Values */
{
  int                   i;              /* Looping var */
  ipp_tag_t             temp_tag;       /* Temporary value tag (masked) */
  ipp_attribute_t       *attr;          /* New attribute */
  _ipp_value_t          *value;         /* Current value */
  char                  code[32];       /* Language/charset value buffer */


  DEBUG_printf(("ippAddStrings(ipp=%p, group=%02x(%s), value_tag=%02x(%s), "
                "name=\"%s\", num_values=%d, language=\"%s\", values=%p)", ipp,
                group, ippTagString(group), value_tag, ippTagString(value_tag), name,
                num_values, language, values));

 /*
  * Range check input...
  */

  temp_tag = (ipp_tag_t)((int)value_tag & IPP_TAG_MASK);

#if 0
  if (!ipp || !name || group < IPP_TAG_ZERO ||
      group == IPP_TAG_END || group >= IPP_TAG_UNSUPPORTED_VALUE ||
      (temp_tag < IPP_TAG_TEXT && temp_tag != IPP_TAG_TEXTLANG &&
       temp_tag != IPP_TAG_NAMELANG) || temp_tag > IPP_TAG_MIMETYPE ||
      num_values < 1)
    return (NULL);

  if ((temp_tag == IPP_TAG_TEXTLANG || temp_tag == IPP_TAG_NAMELANG)
          != (language != NULL))
    return (NULL);
#else
  if (!ipp || !name || group < IPP_TAG_ZERO ||
      group == IPP_TAG_END || group >= IPP_TAG_UNSUPPORTED_VALUE ||
      num_values < 1)
    return (NULL);
#endif /* 0 */

 /*
  * See if we need to map charset, language, or locale values...
  */

  if (language && ((int)value_tag & IPP_TAG_COPY) &&
      strcmp(language, ipp_lang_code(language, code, sizeof(code))))
    value_tag = temp_tag;               /* Don't do a fast copy */
  else if (values && value_tag == (ipp_tag_t)(IPP_TAG_CHARSET | IPP_TAG_COPY))
  {
    for (i = 0; i < num_values; i ++)
      if (strcmp(values[i], ipp_get_code(values[i], code, sizeof(code))))
      {
        value_tag = temp_tag;           /* Don't do a fast copy */
        break;
      }
  }
  else if (values && value_tag == (ipp_tag_t)(IPP_TAG_LANGUAGE | IPP_TAG_COPY))
  {
    for (i = 0; i < num_values; i ++)
      if (strcmp(values[i], ipp_lang_code(values[i], code, sizeof(code))))
      {
        value_tag = temp_tag;           /* Don't do a fast copy */
        break;
      }
  }

 /*
  * Create the attribute...
  */

  if ((attr = ipp_add_attr(ipp, name, group, value_tag, num_values)) == NULL)
    return (NULL);

 /*
  * Initialize the attribute data...
  */

  for (i = num_values, value = attr->values;
       i > 0;
       i --, value ++)
  {
    if (language)
    {
      if (value == attr->values)
      {
        if ((int)value_tag & IPP_TAG_COPY)
          value->string.language = (char *)language;
        else
          value->string.language = _cupsStrAlloc(ipp_lang_code(language, code,
                                                               sizeof(code)));
      }
      else
        value->string.language = attr->values[0].string.language;
    }

    if (values)
    {
      if ((int)value_tag & IPP_TAG_COPY)
        value->string.text = (char *)*values++;
      else if (value_tag == IPP_TAG_CHARSET)
        value->string.text = _cupsStrAlloc(ipp_get_code(*values++, code, sizeof(code)));
      else if (value_tag == IPP_TAG_LANGUAGE)
        value->string.text = _cupsStrAlloc(ipp_lang_code(*values++, code, sizeof(code)));
      else
        value->string.text = _cupsStrAlloc(*values++);
    }
  }

  return (attr);
}


/*
 * 'ippCopyAttribute()' - Copy an attribute.
 *
 * The specified attribute, @code attr@, is copied to the destination IPP message.
 * When @code quickcopy@ is non-zero, a "shallow" reference copy of the attribute is
 * created - this should only be done as long as the original source IPP message will
 * not be freed for the life of the destination.
 *
 * @since CUPS 1.6@
 */


ipp_attribute_t *                       /* O - New attribute */
ippCopyAttribute(
    ipp_t           *dst,               /* I - Destination IPP message */
    ipp_attribute_t *srcattr,           /* I - Attribute to copy */
    int             quickcopy)          /* I - 1 for a referenced copy, 0 for normal */
{
  int                   i;              /* Looping var */
  ipp_attribute_t       *dstattr;       /* Destination attribute */
  _ipp_value_t          *srcval,        /* Source value */
                        *dstval;        /* Destination value */


  DEBUG_printf(("ippCopyAttribute(dst=%p, srcattr=%p, quickcopy=%d)", dst, srcattr,
                quickcopy));

 /*
  * Range check input...
  */

  if (!dst || !srcattr)
    return (NULL);

 /*
  * Copy it...
  */

  quickcopy = quickcopy ? IPP_TAG_COPY : 0;

  switch (srcattr->value_tag & ~IPP_TAG_COPY)
  {
    case IPP_TAG_ZERO :
        dstattr = ippAddSeparator(dst);
        break;

    case IPP_TAG_INTEGER :
    case IPP_TAG_ENUM :
        dstattr = ippAddIntegers(dst, srcattr->group_tag, srcattr->value_tag,
                                 srcattr->name, srcattr->num_values, NULL);
        if (!dstattr)
          break;

        for (i = srcattr->num_values, srcval = srcattr->values, dstval = dstattr->values;
             i > 0;
             i --, srcval ++, dstval ++)
          dstval->integer = srcval->integer;
        break;

    case IPP_TAG_BOOLEAN :
        dstattr = ippAddBooleans(dst, srcattr->group_tag, srcattr->name,
                                srcattr->num_values, NULL);
        if (!dstattr)
          break;

        for (i = srcattr->num_values, srcval = srcattr->values, dstval = dstattr->values;
             i > 0;
             i --, srcval ++, dstval ++)
          dstval->boolean = srcval->boolean;
        break;

    case IPP_TAG_TEXT :
    case IPP_TAG_NAME :
    case IPP_TAG_KEYWORD :
    case IPP_TAG_URI :
    case IPP_TAG_URISCHEME :
    case IPP_TAG_CHARSET :
    case IPP_TAG_LANGUAGE :
    case IPP_TAG_MIMETYPE :
        dstattr = ippAddStrings(dst, srcattr->group_tag,
                                (ipp_tag_t)(srcattr->value_tag | quickcopy),
                                srcattr->name, srcattr->num_values, NULL, NULL);
        if (!dstattr)
          break;

        if (quickcopy)
        {
          for (i = srcattr->num_values, srcval = srcattr->values,
                   dstval = dstattr->values;
               i > 0;
               i --, srcval ++, dstval ++)
            dstval->string.text = srcval->string.text;
        }
        else if (srcattr->value_tag & IPP_TAG_COPY)
        {
          for (i = srcattr->num_values, srcval = srcattr->values,
                   dstval = dstattr->values;
               i > 0;
               i --, srcval ++, dstval ++)
            dstval->string.text = _cupsStrAlloc(srcval->string.text);
        }
        else
        {
          for (i = srcattr->num_values, srcval = srcattr->values,
                   dstval = dstattr->values;
               i > 0;
               i --, srcval ++, dstval ++)
            dstval->string.text = _cupsStrRetain(srcval->string.text);
        }
        break;

    case IPP_TAG_DATE :
        if (srcattr->num_values != 1)
          return (NULL);

        dstattr = ippAddDate(dst, srcattr->group_tag, srcattr->name,
                             srcattr->values[0].date);
        break;

    case IPP_TAG_RESOLUTION :
        dstattr = ippAddResolutions(dst, srcattr->group_tag, srcattr->name,
                                    srcattr->num_values, IPP_RES_PER_INCH,
                                    NULL, NULL);
        if (!dstattr)
          break;

        for (i = srcattr->num_values, srcval = srcattr->values, dstval = dstattr->values;
             i > 0;
             i --, srcval ++, dstval ++)
        {
          dstval->resolution.xres  = srcval->resolution.xres;
          dstval->resolution.yres  = srcval->resolution.yres;
          dstval->resolution.units = srcval->resolution.units;
        }
        break;

    case IPP_TAG_RANGE :
        dstattr = ippAddRanges(dst, srcattr->group_tag, srcattr->name,
                               srcattr->num_values, NULL, NULL);
        if (!dstattr)
          break;

        for (i = srcattr->num_values, srcval = srcattr->values, dstval = dstattr->values;
             i > 0;
             i --, srcval ++, dstval ++)
        {
          dstval->range.lower = srcval->range.lower;
          dstval->range.upper = srcval->range.upper;
        }
        break;

    case IPP_TAG_TEXTLANG :
    case IPP_TAG_NAMELANG :
        dstattr = ippAddStrings(dst, srcattr->group_tag,
                                (ipp_tag_t)(srcattr->value_tag | quickcopy),
                                srcattr->name, srcattr->num_values, NULL, NULL);
        if (!dstattr)
          break;

        if (quickcopy)
        {
          for (i = srcattr->num_values, srcval = srcattr->values,
                   dstval = dstattr->values;
               i > 0;
               i --, srcval ++, dstval ++)
          {
            dstval->string.language = srcval->string.language;
            dstval->string.text     = srcval->string.text;
          }
        }
        else if (srcattr->value_tag & IPP_TAG_COPY)
        {
          for (i = srcattr->num_values, srcval = srcattr->values,
                   dstval = dstattr->values;
               i > 0;
               i --, srcval ++, dstval ++)
          {
            if (srcval == srcattr->values)
              dstval->string.language = _cupsStrAlloc(srcval->string.language);
            else
              dstval->string.language = dstattr->values[0].string.language;

            dstval->string.text = _cupsStrAlloc(srcval->string.text);
          }
        }
        else
        {
          for (i = srcattr->num_values, srcval = srcattr->values,
                   dstval = dstattr->values;
               i > 0;
               i --, srcval ++, dstval ++)
          {
            if (srcval == srcattr->values)
              dstval->string.language = _cupsStrRetain(srcval->string.language);
            else
              dstval->string.language = dstattr->values[0].string.language;

            dstval->string.text = _cupsStrRetain(srcval->string.text);
          }
        }
        break;

    case IPP_TAG_BEGIN_COLLECTION :
        dstattr = ippAddCollections(dst, srcattr->group_tag, srcattr->name,
                                    srcattr->num_values, NULL);
        if (!dstattr)
          break;

        for (i = srcattr->num_values, srcval = srcattr->values, dstval = dstattr->values;
             i > 0;
             i --, srcval ++, dstval ++)
        {
          dstval->collection = srcval->collection;
          srcval->collection->use ++;
        }
        break;

    case IPP_TAG_STRING :
    default :
        /* TODO: Implement quick copy for unknown/octetString values */
        dstattr = ippAddIntegers(dst, srcattr->group_tag, srcattr->value_tag,
                                 srcattr->name, srcattr->num_values, NULL);
        if (!dstattr)
          break;

        for (i = srcattr->num_values, srcval = srcattr->values, dstval = dstattr->values;
             i > 0;
             i --, srcval ++, dstval ++)
        {
          dstval->unknown.length = srcval->unknown.length;

          if (dstval->unknown.length > 0)
          {
            if ((dstval->unknown.data = malloc(dstval->unknown.length)) == NULL)
              dstval->unknown.length = 0;
            else
              memcpy(dstval->unknown.data, srcval->unknown.data, dstval->unknown.length);
          }
        }
        break; /* anti-compiler-warning-code */
  }

  return (dstattr);
}


/*
 * 'ippCopyAttributes()' - Copy attributes from one IPP message to another.
 *
 * Zero or more attributes are copied from the source IPP message, @code@ src, to the
 * destination IPP message, @code dst@. When @code quickcopy@ is non-zero, a "shallow"
 * reference copy of the attribute is created - this should only be done as long as the
 * original source IPP message will not be freed for the life of the destination.
 *
 * The @code cb@ and @code context@ parameters provide a generic way to "filter" the
 * attributes that are copied - the function must return 1 to copy the attribute or
 * 0 to skip it. The function may also choose to do a partial copy of the source attribute
 * itself.
 *
 * @since CUPS 1.6@
 */

int                                     /* O - 1 on success, 0 on error */
ippCopyAttributes(
    ipp_t        *dst,                  /* I - Destination IPP message */
    ipp_t        *src,                  /* I - Source IPP message */
    int          quickcopy,             /* I - 1 for a referenced copy, 0 for normal */
    ipp_copycb_t cb,                    /* I - Copy callback or @code NULL@ for none */
    void         *context)              /* I - Context pointer */
{
  ipp_attribute_t       *srcattr;       /* Source attribute */


  DEBUG_printf(("ippCopyAttributes(dst=%p, src=%p, quickcopy=%d, cb=%p, context=%p)",
                dst, src, quickcopy, cb, context));

 /*
  * Range check input...
  */

  if (!dst || !src)
    return (0);

 /*
  * Loop through source attributes and copy as needed...
  */

  for (srcattr = src->attrs; srcattr; srcattr = srcattr->next)
    if (!cb || (*cb)(context, dst, srcattr))
      if (!ippCopyAttribute(dst, srcattr, quickcopy))
        return (0);

  return (1);
}


/*
 * 'ippDateToTime()' - Convert from RFC 1903 Date/Time format to UNIX time
 *                     in seconds.
 */

time_t                                  /* O - UNIX time value */
ippDateToTime(const ipp_uchar_t *date)  /* I - RFC 1903 date info */
{
  struct tm     unixdate;               /* UNIX date/time info */
  time_t        t;                      /* Computed time */


  if (!date)
    return (0);

  memset(&unixdate, 0, sizeof(unixdate));

 /*
  * RFC-1903 date/time format is:
  *
  *    Byte(s)  Description
  *    -------  -----------
  *    0-1      Year (0 to 65535)
  *    2        Month (1 to 12)
  *    3        Day (1 to 31)
  *    4        Hours (0 to 23)
  *    5        Minutes (0 to 59)
  *    6        Seconds (0 to 60, 60 = "leap second")
  *    7        Deciseconds (0 to 9)
  *    8        +/- UTC
  *    9        UTC hours (0 to 11)
  *    10       UTC minutes (0 to 59)
  */

  unixdate.tm_year = ((date[0] << 8) | date[1]) - 1900;
  unixdate.tm_mon  = date[2] - 1;
  unixdate.tm_mday = date[3];
  unixdate.tm_hour = date[4];
  unixdate.tm_min  = date[5];
  unixdate.tm_sec  = date[6];

  t = mktime(&unixdate);

  if (date[8] == '-')
    t += date[9] * 3600 + date[10] * 60;
  else
    t -= date[9] * 3600 + date[10] * 60;

  return (t);
}


/*
 * 'ippDelete()' - Delete an IPP message.
 */

void
ippDelete(ipp_t *ipp)                   /* I - IPP message */
{
  ipp_attribute_t       *attr,          /* Current attribute */
                        *next;          /* Next attribute */


  DEBUG_printf(("ippDelete(ipp=%p)", ipp));

  if (!ipp)
    return;

  ipp->use --;
  if (ipp->use > 0)
    return;

  for (attr = ipp->attrs; attr != NULL; attr = next)
  {
    next = attr->next;

    ipp_free_values(attr, 0, attr->num_values);

    if (attr->name)
      _cupsStrFree(attr->name);

    free(attr);
  }

  free(ipp);
}


/*
 * 'ippDeleteAttribute()' - Delete a single attribute in an IPP message.
 *
 * @since CUPS 1.1.19/Mac OS X 10.3@
 */

void
ippDeleteAttribute(
    ipp_t           *ipp,               /* I - IPP message */
    ipp_attribute_t *attr)              /* I - Attribute to delete */
{
  ipp_attribute_t       *current,       /* Current attribute */
                        *prev;          /* Previous attribute */


  DEBUG_printf(("ippDeleteAttribute(ipp=%p, attr=%p(%s))", ipp, attr,
                attr ? attr->name : "(null)"));

 /*
  * Range check input...
  */

  if (!attr)
    return;

 /*
  * Find the attribute in the list...
  */

  if (ipp)
  {
    for (current = ipp->attrs, prev = NULL;
         current;
         prev = current, current = current->next)
      if (current == attr)
      {
       /*
        * Found it, remove the attribute from the list...
        */

        if (prev)
          prev->next = current->next;
        else
          ipp->attrs = current->next;

        if (current == ipp->last)
          ipp->last = prev;

        break;
      }

    if (!current)
      return;
  }

 /*
  * Free memory used by the attribute...
  */

  ipp_free_values(attr, 0, attr->num_values);

  if (attr->name)
    _cupsStrFree(attr->name);

  free(attr);
}


/*
 * 'ippDeleteValues()' - Delete values in an attribute.
 *
 * The @code element@ parameter specifies the first value to delete, starting at
 * 0. It must be less than the number of values returned by @link ippGetCount@.
 *
 * The @code attr@ parameter may be modified as a result of setting the value.
 *
 * Deleting all values in an attribute deletes the attribute.
 *
 * @since CUPS 1.6@
 */

int                                     /* O  - 1 on success, 0 on failure */
ippDeleteValues(
    ipp_t           *ipp,               /* I  - IPP message */
    ipp_attribute_t **attr,             /* IO - Attribute */
    int             element,            /* I  - Index of first value to delete (0-based) */
    int             count)              /* I  - Number of values to delete */
{
 /*
  * Range check input...
  */

  if (!ipp || !attr || !*attr ||
      element < 0 || element >= (*attr)->num_values || count <= 0 ||
      (element + count) >= (*attr)->num_values)
    return (0);

 /*
  * If we are deleting all values, just delete the attribute entirely.
  */

  if (count == (*attr)->num_values)
  {
    ippDeleteAttribute(ipp, *attr);
    *attr = NULL;
    return (1);
  }

 /*
  * Otherwise free the values in question and return.
  */

  ipp_free_values(*attr, element, count);

  return (1);
}


/*
 * 'ippFindAttribute()' - Find a named attribute in a request.
 */

ipp_attribute_t *                       /* O - Matching attribute */
ippFindAttribute(ipp_t      *ipp,       /* I - IPP message */
                 const char *name,      /* I - Name of attribute */
                 ipp_tag_t  type)       /* I - Type of attribute */
{
  DEBUG_printf(("2ippFindAttribute(ipp=%p, name=\"%s\", type=%02x(%s))", ipp,
                name, type, ippTagString(type)));

  if (!ipp || !name)
    return (NULL);

 /*
  * Reset the current pointer...
  */

  ipp->current = NULL;

 /*
  * Search for the attribute...
  */

  return (ippFindNextAttribute(ipp, name, type));
}


/*
 * 'ippFindNextAttribute()' - Find the next named attribute in a request.
 */

ipp_attribute_t *                       /* O - Matching attribute */
ippFindNextAttribute(ipp_t      *ipp,   /* I - IPP message */
                     const char *name,  /* I - Name of attribute */
                     ipp_tag_t  type)   /* I - Type of attribute */
{
  ipp_attribute_t       *attr;          /* Current atttribute */
  ipp_tag_t             value_tag;      /* Value tag */


  DEBUG_printf(("2ippFindNextAttribute(ipp=%p, name=\"%s\", type=%02x(%s))",
                ipp, name, type, ippTagString(type)));

  if (!ipp || !name)
    return (NULL);

  if (ipp->current)
  {
    ipp->prev = ipp->current;
    attr      = ipp->current->next;
  }
  else
  {
    ipp->prev = NULL;
    attr      = ipp->attrs;
  }

  for (; attr != NULL; ipp->prev = attr, attr = attr->next)
  {
    DEBUG_printf(("4ippFindAttribute: attr=%p, name=\"%s\"", attr,
                  attr->name));

    value_tag = (ipp_tag_t)(attr->value_tag & IPP_TAG_MASK);

    if (attr->name != NULL && _cups_strcasecmp(attr->name, name) == 0 &&
        (value_tag == type || type == IPP_TAG_ZERO ||
         (value_tag == IPP_TAG_TEXTLANG && type == IPP_TAG_TEXT) ||
         (value_tag == IPP_TAG_NAMELANG && type == IPP_TAG_NAME)))
    {
      ipp->current = attr;

      return (attr);
    }
  }

  ipp->current = NULL;
  ipp->prev    = NULL;

  return (NULL);
}


/*
 * 'ippFirstAttribute()' - Return the first attribute in the message.
 *
 * @since CUPS 1.6@
 */

ipp_attribute_t *                       /* O - First attribute or @code NULL@ if none */
ippFirstAttribute(ipp_t *ipp)           /* I - IPP message */
{
 /*
  * Range check input...
  */

  if (!ipp)
    return (NULL);

 /*
  * Return the first attribute...
  */

  return (ipp->current = ipp->attrs);
}


/*
 * 'ippGetBoolean()' - Get a boolean value for an attribute.
 *
 * The @code element@ parameter specifies which value to get from 0 to
 * @link ippGetCount(attr)@ - 1.
 *
 * @since CUPS 1.6@
 */

int                                     /* O - Boolean value or -1 on error */
ippGetBoolean(ipp_attribute_t *attr,    /* I - IPP attribute */
              int             element)  /* I - Value number (0-based) */
{
 /*
  * Range check input...
  */

  if (!attr || attr->value_tag != IPP_TAG_BOOLEAN ||
      element < 0 || element >= attr->num_values)
    return (-1);

 /*
  * Return the value...
  */

  return (attr->values[element].boolean);
}


/*
 * 'ippGetCollection()' - Get a collection value for an attribute.
 *
 * The @code element@ parameter specifies which value to get from 0 to
 * @link ippGetCount(attr)@ - 1.
 *
 * @since CUPS 1.6@
 */

ipp_t *                                 /* O - Collection value or @code NULL@ on error */
ippGetCollection(
    ipp_attribute_t *attr,              /* I - IPP attribute */
    int             element)            /* I - Value number (0-based) */
{
 /*
  * Range check input...
  */

  if (!attr || attr->value_tag != IPP_TAG_BEGIN_COLLECTION ||
      element < 0 || element >= attr->num_values)
    return (NULL);

 /*
  * Return the value...
  */

  return (attr->values[element].collection);
}


/*
 * 'ippGetCount()' - Get the number of values in an attribute.
 *
 * @since CUPS 1.6@
 */

int                                     /* O - Number of values or -1 on error */
ippGetCount(ipp_attribute_t *attr)      /* I - IPP attribute */
{
 /*
  * Range check input...
  */

  if (!attr)
    return (-1);

 /*
  * Return the number of values...
  */

  return (attr->num_values);
}


/*
 * 'ippGetDate()' - Get a date value for an attribute.
 *
 * The @code element@ parameter specifies which value to get from 0 to
 * @link ippGetCount(attr)@ - 1.
 *
 * @since CUPS 1.6@
 */

const ipp_uchar_t *                     /* O - Date value or @code NULL@ */
ippGetDate(ipp_attribute_t *attr,       /* I - IPP attribute */
           int             element)     /* I - Value number (0-based) */
{
 /*
  * Range check input...
  */

  if (!attr || attr->value_tag != IPP_TAG_DATE ||
      element < 0 || element >= attr->num_values)
    return (NULL);

 /*
  * Return the value...
  */

  return (attr->values[element].date);
}


/*
 * 'ippGetGroupTag()' - Get the group associated with an attribute.
 *
 * @since CUPS 1.6@
 */

ipp_tag_t                               /* O - Group tag or @code IPP_TAG_ZERO@ on error */
ippGetGroupTag(ipp_attribute_t *attr)   /* I - IPP attribute */
{
 /*
  * Range check input...
  */

  if (!attr)
    return (IPP_TAG_ZERO);

 /*
  * Return the group...
  */

  return (attr->group_tag);
}


/*
 * 'ippGetInteger()' - Get the integer/enum value for an attribute.
 *
 * The @code element@ parameter specifies which value to get from 0 to
 * @link ippGetCount(attr)@ - 1.
 *
 * @since CUPS 1.6@
 */

int                                     /* O - Value or -1 on error */
ippGetInteger(ipp_attribute_t *attr,    /* I - IPP attribute */
              int             element)  /* I - Value number (0-based) */
{
 /*
  * Range check input...
  */

  if (!attr || (attr->value_tag != IPP_TAG_INTEGER && attr->value_tag != IPP_TAG_ENUM) ||
      element < 0 || element >= attr->num_values)
    return (-1);

 /*
  * Return the value...
  */

  return (attr->values[element].integer);
}


/*
 * 'ippGetName()' - Get the attribute name.
 *
 * @since CUPS 1.6@
 */

const char *                            /* O - Attribute name or @code NULL@ for separators */
ippGetName(ipp_attribute_t *attr)       /* I - IPP attribute */
{
 /*
  * Range check input...
  */

  if (!attr)
    return (NULL);

 /*
  * Return the name...
  */

  return (attr->name);
}


/*
 * 'ippGetOperation()' - Get the operation ID in an IPP message.
 *
 * @since CUPS 1.6@
 */

ipp_op_t                                /* O - Operation ID or -1 on error */
ippGetOperation(ipp_t *ipp)             /* I - IPP request message */
{
 /*
  * Range check input...
  */

  if (!ipp)
    return ((ipp_op_t)-1);

 /*
  * Return the value...
  */

  return (ipp->request.op.operation_id);
}


/*
 * 'ippGetRange()' - Get a rangeOfInteger value from an attribute.
 *
 * The @code element@ parameter specifies which value to get from 0 to
 * @link ippGetCount(attr)@ - 1.
 *
 * @since CUPS 1.6@
 */

int                                     /* O - Lower value of range or -1 */
ippGetRange(ipp_attribute_t *attr,      /* I - IPP attribute */
            int             element,    /* I - Value number (0-based) */
            int             *uppervalue)/* O - Upper value of range */
{
 /*
  * Range check input...
  */

  if (!attr || attr->value_tag != IPP_TAG_RANGE ||
      element < 0 || element >= attr->num_values)
  {
    if (uppervalue)
      *uppervalue = -1;

    return (-1);
  }

 /*
  * Return the values...
  */

  if (uppervalue)
    *uppervalue = attr->values[element].range.upper;

  return (attr->values[element].range.lower);
}


/*
 * 'ippGetRequestId()' - Get the request ID from an IPP message.
 *
 * @since CUPS 1.6@
 */

int                                     /* O - Request ID or -1 on error */
ippGetRequestId(ipp_t *ipp)             /* I - IPP message */
{
 /*
  * Range check input...
  */

  if (!ipp)
    return (-1);

 /*
  * Return the request ID...
  */

  return (ipp->request.any.request_id);
}


/*
 * 'ippGetResolution()' - Get a resolution value for an attribute.
 *
 * The @code element@ parameter specifies which value to get from 0 to
 * @link ippGetCount(attr)@ - 1.
 *
 * @since CUPS 1.6@
 */

int                                     /* O - Horizontal/cross feed resolution or -1 */
ippGetResolution(
    ipp_attribute_t *attr,              /* I - IPP attribute */
    int             element,            /* I - Value number (0-based) */
    int             *yres,              /* O - Vertical/feed resolution */
    ipp_res_t       *units)             /* O - Units for resolution */
{
 /*
  * Range check input...
  */

  if (!attr || attr->value_tag != IPP_TAG_RESOLUTION ||
      element < 0 || element >= attr->num_values)
    return (-1);

 /*
  * Return the value...
  */

  if (yres)
    *yres = attr->values[element].resolution.yres;

  if (units)
    *units = attr->values[element].resolution.units;

  return (attr->values[element].resolution.xres);
}


/*
 * 'ippGetState()' - Get the IPP message state.
 *
 * @since CUPS 1.6@
 */

ipp_state_t                             /* O - IPP message state value */
ippGetState(ipp_t *ipp)                 /* I - IPP message */
{
 /*
  * Range check input...
  */

  if (!ipp)
    return (IPP_IDLE);

 /*
  * Return the value...
  */

  return (ipp->state);
}


/*
 * 'ippGetStatusCode()' - Get the status code from an IPP response or event message.
 *
 * @since CUPS 1.6@
 */

ipp_status_t                            /* O - Status code in IPP message */
ippGetStatusCode(ipp_t *ipp)            /* I - IPP response or event message */
{
 /*
  * Range check input...
  */

  if (!ipp)
    return (IPP_INTERNAL_ERROR);

 /*
  * Return the value...
  */

  return (ipp->request.status.status_code);
}


/*
 * 'ippGetString()' - Get the string and optionally the language code for an attribute.
 *
 * The @code element@ parameter specifies which value to get from 0 to
 * @link ippGetCount(attr)@ - 1.
 *
 * @since CUPS 1.6@
 */

const char *
ippGetString(ipp_attribute_t *attr,     /* I - IPP attribute */
             int             element,   /* I - Value number (0-based) */
             const char      **language)/* O - Language code (@code NULL@ for don't care) */
{
 /*
  * Range check input...
  */

  if (!attr || element < 0 || element >= attr->num_values ||
      (attr->value_tag != IPP_TAG_TEXTLANG && attr->value_tag != IPP_TAG_NAMELANG &&
       (attr->value_tag < IPP_TAG_TEXT || attr->value_tag > IPP_TAG_MIMETYPE)))
    return (NULL);

 /*
  * Return the value...
  */

  if (language)
    *language = attr->values[element].string.language;

  return (attr->values[element].string.text);
}


/*
 * 'ippGetValueTag()' - Get the value tag for an attribute.
 *
 * @since CUPS 1.6@
 */

ipp_tag_t                               /* O - Value tag or @code IPP_TAG_ZERO@ on error */
ippGetValueTag(ipp_attribute_t *attr)   /* I - IPP attribute */
{
 /*
  * Range check input...
  */

  if (!attr)
    return (IPP_TAG_ZERO);

 /*
  * Return the value...
  */

  return (attr->value_tag);
}


/*
 * 'ippGetVersion()' - Get the major and minor version number from an IPP message.
 *
 * @since CUPS 1.6@
 */

int                                     /* O - Major version number or -1 on error */
ippGetVersion(ipp_t *ipp,               /* I - IPP message */
              int   *minor)             /* O - Minor version number or @code NULL@ */
{
 /*
  * Range check input...
  */

  if (!ipp)
  {
    if (minor)
      *minor = -1;

    return (-1);
  }

 /*
  * Return the value...
  */

  if (minor)
    *minor = ipp->request.any.version[1];

  return (ipp->request.any.version[0]);
}


/*
 * 'ippLength()' - Compute the length of an IPP message.
 */

size_t                                  /* O - Size of IPP message */
ippLength(ipp_t *ipp)                   /* I - IPP message */
{
  return (ipp_length(ipp, 0));
}


/*
 * 'ippNextAttribute()' - Return the next attribute in the message.
 *
 * @since CUPS 1.6@
 */

ipp_attribute_t *                       /* O - Next attribute or @code NULL@ if none */
ippNextAttribute(ipp_t *ipp)            /* I - IPP message */
{
 /*
  * Range check input...
  */

  if (!ipp || !ipp->current)
    return (NULL);

 /*
  * Return the next attribute...
  */

  return (ipp->current = ipp->current->next);
}


/*
 * 'ippNew()' - Allocate a new IPP message.
 */

ipp_t *                                 /* O - New IPP message */
ippNew(void)
{
  ipp_t *temp;                          /* New IPP message */


  DEBUG_puts("ippNew()");

  if ((temp = (ipp_t *)calloc(1, sizeof(ipp_t))) != NULL)
  {
   /*
    * Default to IPP 2.0...
    */

    temp->request.any.version[0] = 2;
    temp->request.any.version[1] = 0;
    temp->use                    = 1;
  }

  DEBUG_printf(("1ippNew: Returning %p", temp));

  return (temp);
}


/*
 *  'ippNewRequest()' - Allocate a new IPP request message.
 *
 * The new request message is initialized with the attributes-charset and
 * attributes-natural-language attributes added. The
 * attributes-natural-language value is derived from the current locale.
 *
 * @since CUPS 1.2/Mac OS X 10.5@
 */

ipp_t *                                 /* O - IPP request message */
ippNewRequest(ipp_op_t op)              /* I - Operation code */
{
  ipp_t         *request;               /* IPP request message */
  cups_lang_t   *language;              /* Current language localization */
  static int    request_id = 0;         /* Current request ID */
  static _cups_mutex_t request_mutex = _CUPS_MUTEX_INITIALIZER;
                                        /* Mutex for request ID */


  DEBUG_printf(("ippNewRequest(op=%02x(%s))", op, ippOpString(op)));

 /*
  * Create a new IPP message...
  */

  if ((request = ippNew()) == NULL)
    return (NULL);

 /*
  * Set the operation and request ID...
  */

  _cupsMutexLock(&request_mutex);

  request->request.op.operation_id = op;
  request->request.op.request_id   = ++request_id;

  _cupsMutexUnlock(&request_mutex);

 /*
  * Use UTF-8 as the character set...
  */

  ippAddString(request, IPP_TAG_OPERATION, IPP_TAG_CHARSET,
               "attributes-charset", NULL, "utf-8");

 /*
  * Get the language from the current locale...
  */

  language = cupsLangDefault();

  ippAddString(request, IPP_TAG_OPERATION, IPP_TAG_LANGUAGE,
               "attributes-natural-language", NULL, language->language);

 /*
  * Return the new request...
  */

  return (request);
}


/*
 * 'ippRead()' - Read data for an IPP message from a HTTP connection.
 */

ipp_state_t                             /* O - Current state */
ippRead(http_t *http,                   /* I - HTTP connection */
        ipp_t  *ipp)                    /* I - IPP data */
{
  DEBUG_printf(("ippRead(http=%p, ipp=%p), data_remaining=" CUPS_LLFMT,
                http, ipp, CUPS_LLCAST (http ? http->data_remaining : -1)));

  if (!http)
    return (IPP_ERROR);

  DEBUG_printf(("2ippRead: http->state=%d, http->used=%d", http->state,
                http->used));

  return (ippReadIO(http, (ipp_iocb_t)ipp_read_http, http->blocking, NULL,
                    ipp));
}


/*
 * 'ippReadFile()' - Read data for an IPP message from a file.
 *
 * @since CUPS 1.1.19/Mac OS X 10.3@
 */

ipp_state_t                             /* O - Current state */
ippReadFile(int   fd,                   /* I - HTTP data */
            ipp_t *ipp)                 /* I - IPP data */
{
  DEBUG_printf(("ippReadFile(fd=%d, ipp=%p)", fd, ipp));

  return (ippReadIO(&fd, (ipp_iocb_t)ipp_read_file, 1, NULL, ipp));
}


/*
 * 'ippReadIO()' - Read data for an IPP message.
 *
 * @since CUPS 1.2/Mac OS X 10.5@
 */

ipp_state_t                             /* O - Current state */
ippReadIO(void       *src,              /* I - Data source */
          ipp_iocb_t cb,                /* I - Read callback function */
          int        blocking,          /* I - Use blocking IO? */
          ipp_t      *parent,           /* I - Parent request, if any */
          ipp_t      *ipp)              /* I - IPP data */
{
  int                   n;              /* Length of data */
  unsigned char         *buffer,        /* Data buffer */
                        string[IPP_MAX_NAME],
                                        /* Small string buffer */
                        *bufptr;        /* Pointer into buffer */
  ipp_attribute_t       *attr;          /* Current attribute */
  ipp_tag_t             tag;            /* Current tag */
  ipp_tag_t             value_tag;      /* Current value tag */
  _ipp_value_t          *value;         /* Current value */


  DEBUG_printf(("ippReadIO(src=%p, cb=%p, blocking=%d, parent=%p, ipp=%p)",
                src, cb, blocking, parent, ipp));
  DEBUG_printf(("2ippReadIO: ipp->state=%d", ipp->state));

  if (!src || !ipp)
    return (IPP_ERROR);

  if ((buffer = ipp_buffer_get()) == NULL)
  {
    DEBUG_puts("1ippReadIO: Unable to get read buffer.");
    return (IPP_ERROR);
  }

  switch (ipp->state)
  {
    case IPP_IDLE :
        ipp->state ++; /* Avoid common problem... */

    case IPP_HEADER :
        if (parent == NULL)
        {
         /*
          * Get the request header...
          */

          if ((*cb)(src, buffer, 8) < 8)
          {
            DEBUG_puts("1ippReadIO: Unable to read header.");
            ipp_buffer_release(buffer);
            return (IPP_ERROR);
          }

         /*
          * Then copy the request header over...
          */

          ipp->request.any.version[0]  = buffer[0];
          ipp->request.any.version[1]  = buffer[1];
          ipp->request.any.op_status   = (buffer[2] << 8) | buffer[3];
          ipp->request.any.request_id  = (((((buffer[4] << 8) | buffer[5]) << 8) |
                                         buffer[6]) << 8) | buffer[7];

          DEBUG_printf(("2ippReadIO: version=%d.%d", buffer[0], buffer[1]));
          DEBUG_printf(("2ippReadIO: op_status=%04x",
                        ipp->request.any.op_status));
          DEBUG_printf(("2ippReadIO: request_id=%d",
                        ipp->request.any.request_id));
        }

        ipp->state   = IPP_ATTRIBUTE;
        ipp->current = NULL;
        ipp->curtag  = IPP_TAG_ZERO;
        ipp->prev    = ipp->last;

       /*
        * If blocking is disabled, stop here...
        */

        if (!blocking)
          break;

    case IPP_ATTRIBUTE :
        for (;;)
        {
          if ((*cb)(src, buffer, 1) < 1)
          {
            DEBUG_puts("1ippReadIO: Callback returned EOF/error");
            ipp_buffer_release(buffer);
            return (IPP_ERROR);
          }

          DEBUG_printf(("2ippReadIO: ipp->current=%p, ipp->prev=%p",
                        ipp->current, ipp->prev));

         /*
          * Read this attribute...
          */

          tag = (ipp_tag_t)buffer[0];
          if (tag == IPP_TAG_EXTENSION)
          {
           /*
            * Read 32-bit "extension" tag...
            */

            if ((*cb)(src, buffer, 4) < 1)
            {
              DEBUG_puts("1ippReadIO: Callback returned EOF/error");
              ipp_buffer_release(buffer);
              return (IPP_ERROR);
            }

            tag = (ipp_tag_t)((((((buffer[0] << 8) | buffer[1]) << 8) |
                                buffer[2]) << 8) | buffer[3]);

            if (tag & IPP_TAG_COPY)
            {
             /*
              * Fail if the high bit is set in the tag...
              */

              _cupsSetError(IPP_ERROR, _("IPP extension tag larger than 0x7FFFFFFF."), 1);
              DEBUG_printf(("1ippReadIO: bad name length %d.", n));
              ipp_buffer_release(buffer);
              return (IPP_ERROR);
            }
          }

          if (tag == IPP_TAG_END)
          {
           /*
            * No more attributes left...
            */

            DEBUG_puts("2ippReadIO: IPP_TAG_END.");

            ipp->state = IPP_DATA;
            break;
          }
          else if (tag < IPP_TAG_UNSUPPORTED_VALUE)
          {
           /*
            * Group tag...  Set the current group and continue...
            */

            if (ipp->curtag == tag)
              ipp->prev = ippAddSeparator(ipp);
            else if (ipp->current)
              ipp->prev = ipp->current;

            ipp->curtag  = tag;
            ipp->current = NULL;
            DEBUG_printf(("2ippReadIO: group tag=%x(%s), ipp->prev=%p", tag,
                          ippTagString(tag), ipp->prev));
            continue;
          }

          DEBUG_printf(("2ippReadIO: value tag=%x(%s)", tag,
                        ippTagString(tag)));

         /*
          * Get the name...
          */

          if ((*cb)(src, buffer, 2) < 2)
          {
            DEBUG_puts("1ippReadIO: unable to read name length.");
            ipp_buffer_release(buffer);
            return (IPP_ERROR);
          }

          n = (buffer[0] << 8) | buffer[1];

          if (n >= IPP_BUF_SIZE)
          {
            _cupsSetError(IPP_ERROR, _("IPP name larger than 32767 bytes."), 1);
            DEBUG_printf(("1ippReadIO: bad name length %d.", n));
            ipp_buffer_release(buffer);
            return (IPP_ERROR);
          }

          DEBUG_printf(("2ippReadIO: name length=%d", n));

          if (n == 0 && tag != IPP_TAG_MEMBERNAME &&
              tag != IPP_TAG_END_COLLECTION)
          {
           /*
            * More values for current attribute...
            */

            if (ipp->current == NULL)
            {
              _cupsSetError(IPP_ERROR, _("IPP attribute has no name."), 1);
              DEBUG_puts("1ippReadIO: Attribute without name and no current.");
              ipp_buffer_release(buffer);
              return (IPP_ERROR);
            }

            attr      = ipp->current;
            value_tag = (ipp_tag_t)(attr->value_tag & IPP_TAG_MASK);

           /*
            * Make sure we aren't adding a new value of a different
            * type...
            */

            if (value_tag == IPP_TAG_ZERO)
            {
             /*
              * Setting the value of a collection member...
              */

              attr->value_tag = tag;
            }
            else if (value_tag == IPP_TAG_TEXTLANG ||
                     value_tag == IPP_TAG_NAMELANG ||
                     (value_tag >= IPP_TAG_TEXT &&
                      value_tag <= IPP_TAG_MIMETYPE))
            {
             /*
              * String values can sometimes come across in different
              * forms; accept sets of differing values...
              */

              if (tag != IPP_TAG_TEXTLANG && tag != IPP_TAG_NAMELANG &&
                  (tag < IPP_TAG_TEXT || tag > IPP_TAG_MIMETYPE) &&
                  tag != IPP_TAG_NOVALUE)
              {
                _cupsSetError(IPP_ERROR,
                              _("IPP 1setOf attribute with incompatible value "
                                "tags."), 1);
                DEBUG_printf(("1ippReadIO: 1setOf value tag %x(%s) != %x(%s)",
                              value_tag, ippTagString(value_tag), tag,
                              ippTagString(tag)));
                ipp_buffer_release(buffer);
                return (IPP_ERROR);
              }

              if (value_tag != tag)
              {
                DEBUG_printf(("1ippReadIO: Converting %s attribute from %s to %s.",
                              attr->name, ippTagString(value_tag), ippTagString(tag)));
                ippSetValueTag(ipp, &attr, tag);
              }
            }
            else if (value_tag == IPP_TAG_INTEGER ||
                     value_tag == IPP_TAG_RANGE)
            {
             /*
              * Integer and rangeOfInteger values can sometimes be mixed; accept
              * sets of differing values...
              */

              if (tag != IPP_TAG_INTEGER && tag != IPP_TAG_RANGE)
              {
                _cupsSetError(IPP_ERROR,
                              _("IPP 1setOf attribute with incompatible value "
                                "tags."), 1);
                DEBUG_printf(("1ippReadIO: 1setOf value tag %x(%s) != %x(%s)",
                              value_tag, ippTagString(value_tag), tag,
                              ippTagString(tag)));
                ipp_buffer_release(buffer);
                return (IPP_ERROR);
              }

              if (value_tag == IPP_TAG_INTEGER && tag == IPP_TAG_RANGE)
              {
               /*
                * Convert integer values to rangeOfInteger values...
                */

                DEBUG_printf(("1ippReadIO: Converting %s attribute to "
                              "rangeOfInteger.", attr->name));
                ippSetValueTag(ipp, &attr, IPP_TAG_RANGE);
              }
            }
            else if (value_tag != tag)
            {
              _cupsSetError(IPP_ERROR,
                            _("IPP 1setOf attribute with incompatible value "
                              "tags."), 1);
              DEBUG_printf(("1ippReadIO: value tag %x(%s) != %x(%s)",
                            value_tag, ippTagString(value_tag), tag,
                            ippTagString(tag)));
              ipp_buffer_release(buffer);
              return (IPP_ERROR);
            }

           /*
            * Finally, reallocate the attribute array as needed...
            */

            if ((value = ipp_set_value(ipp, &attr, attr->num_values)) == NULL)
            {
              ipp_buffer_release(buffer);
              return (IPP_ERROR);
            }
          }
          else if (tag == IPP_TAG_MEMBERNAME)
          {
           /*
            * Name must be length 0!
            */

            if (n)
            {
              _cupsSetError(IPP_ERROR, _("IPP member name is not empty."), 1);
              DEBUG_puts("1ippReadIO: member name not empty.");
              ipp_buffer_release(buffer);
              return (IPP_ERROR);
            }

            if (ipp->current)
              ipp->prev = ipp->current;

            attr = ipp->current = ipp_add_attr(ipp, NULL, ipp->curtag, IPP_TAG_ZERO, 1);

            DEBUG_printf(("2ippReadIO: membername, ipp->current=%p, ipp->prev=%p",
                          ipp->current, ipp->prev));

            value = attr->values;
          }
          else if (tag != IPP_TAG_END_COLLECTION)
          {
           /*
            * New attribute; read the name and add it...
            */

            if ((*cb)(src, buffer, n) < n)
            {
              DEBUG_puts("1ippReadIO: unable to read name.");
              ipp_buffer_release(buffer);
              return (IPP_ERROR);
            }

            buffer[n] = '\0';

            if (ipp->current)
              ipp->prev = ipp->current;

            if ((attr = ipp->current = ipp_add_attr(ipp, (char *)buffer, ipp->curtag, tag,
                                                    1)) == NULL)
            {
              _cupsSetHTTPError(HTTP_ERROR);
              DEBUG_puts("1ippReadIO: unable to allocate attribute.");
              ipp_buffer_release(buffer);
              return (IPP_ERROR);
            }

            DEBUG_printf(("2ippReadIO: name=\"%s\", ipp->current=%p, "
                          "ipp->prev=%p", buffer, ipp->current, ipp->prev));

            value = attr->values;
          }
          else
          {
            attr  = NULL;
            value = NULL;
          }

          if ((*cb)(src, buffer, 2) < 2)
          {
            DEBUG_puts("1ippReadIO: unable to read value length.");
            ipp_buffer_release(buffer);
            return (IPP_ERROR);
          }

          n = (buffer[0] << 8) | buffer[1];
          DEBUG_printf(("2ippReadIO: value length=%d", n));

          if (n >= IPP_BUF_SIZE)
          {
            _cupsSetError(IPP_ERROR,
                          _("IPP value larger than 32767 bytes."), 1);
            DEBUG_printf(("1ippReadIO: bad value length %d.", n));
            ipp_buffer_release(buffer);
            return (IPP_ERROR);
          }

          switch (tag)
          {
            case IPP_TAG_INTEGER :
            case IPP_TAG_ENUM :
                if (n != 4)
                {
                  if (tag == IPP_TAG_INTEGER)
                    _cupsSetError(IPP_ERROR,
                                  _("IPP integer value not 4 bytes."), 1);
                  else
                    _cupsSetError(IPP_ERROR,
                                  _("IPP enum value not 4 bytes."), 1);
                  DEBUG_printf(("1ippReadIO: bad value length %d.", n));
                  ipp_buffer_release(buffer);
                  return (IPP_ERROR);
                }

                if ((*cb)(src, buffer, 4) < 4)
                {
                  DEBUG_puts("1ippReadIO: Unable to read integer value.");
                  ipp_buffer_release(buffer);
                  return (IPP_ERROR);
                }

                n = (((((buffer[0] << 8) | buffer[1]) << 8) | buffer[2]) << 8) |
                    buffer[3];

                if (attr->value_tag == IPP_TAG_RANGE)
                  value->range.lower = value->range.upper = n;
                else
                  value->integer = n;
                break;

            case IPP_TAG_BOOLEAN :
                if (n != 1)
                {
                  _cupsSetError(IPP_ERROR, _("IPP boolean value not 1 byte."),
                                1);
                  DEBUG_printf(("1ippReadIO: bad value length %d.", n));
                  ipp_buffer_release(buffer);
                  return (IPP_ERROR);
                }

                if ((*cb)(src, buffer, 1) < 1)
                {
                  DEBUG_puts("1ippReadIO: Unable to read boolean value.");
                  ipp_buffer_release(buffer);
                  return (IPP_ERROR);
                }

                value->boolean = buffer[0];
                break;

            case IPP_TAG_NOVALUE :
            case IPP_TAG_NOTSETTABLE :
            case IPP_TAG_DELETEATTR :
            case IPP_TAG_ADMINDEFINE :
               /*
                * These value types are not supposed to have values, however
                * some vendors (Brother) do not implement IPP correctly and so
                * we need to map non-empty values to text...
                */

                if (attr->value_tag == tag)
                {
                  if (n == 0)
                    break;

                  attr->value_tag = IPP_TAG_TEXT;
                }

            case IPP_TAG_TEXT :
            case IPP_TAG_NAME :
            case IPP_TAG_KEYWORD :
            case IPP_TAG_URI :
            case IPP_TAG_URISCHEME :
            case IPP_TAG_CHARSET :
            case IPP_TAG_LANGUAGE :
            case IPP_TAG_MIMETYPE :
                if ((*cb)(src, buffer, n) < n)
                {
                  DEBUG_puts("1ippReadIO: unable to read string value.");
                  ipp_buffer_release(buffer);
                  return (IPP_ERROR);
                }

                buffer[n] = '\0';
                value->string.text = _cupsStrAlloc((char *)buffer);
                DEBUG_printf(("2ippReadIO: value=\"%s\"", value->string.text));
                break;

            case IPP_TAG_DATE :
                if (n != 11)
                {
                  _cupsSetError(IPP_ERROR, _("IPP date value not 11 bytes."), 1);
                  DEBUG_printf(("1ippReadIO: bad value length %d.", n));
                  ipp_buffer_release(buffer);
                  return (IPP_ERROR);
                }

                if ((*cb)(src, value->date, 11) < 11)
                {
                  DEBUG_puts("1ippReadIO: Unable to read date value.");
                  ipp_buffer_release(buffer);
                  return (IPP_ERROR);
                }
                break;

            case IPP_TAG_RESOLUTION :
                if (n != 9)
                {
                  _cupsSetError(IPP_ERROR,
                                _("IPP resolution value not 9 bytes."), 1);
                  DEBUG_printf(("1ippReadIO: bad value length %d.", n));
                  ipp_buffer_release(buffer);
                  return (IPP_ERROR);
                }

                if ((*cb)(src, buffer, 9) < 9)
                {
                  DEBUG_puts("1ippReadIO: Unable to read resolution value.");
                  ipp_buffer_release(buffer);
                  return (IPP_ERROR);
                }

                value->resolution.xres =
                    (((((buffer[0] << 8) | buffer[1]) << 8) | buffer[2]) << 8) |
                    buffer[3];
                value->resolution.yres =
                    (((((buffer[4] << 8) | buffer[5]) << 8) | buffer[6]) << 8) |
                    buffer[7];
                value->resolution.units =
                    (ipp_res_t)buffer[8];
                break;

            case IPP_TAG_RANGE :
                if (n != 8)
                {
                  _cupsSetError(IPP_ERROR,
                                _("IPP rangeOfInteger value not 8 bytes."), 1);
                  DEBUG_printf(("1ippReadIO: bad value length %d.", n));
                  ipp_buffer_release(buffer);
                  return (IPP_ERROR);
                }

                if ((*cb)(src, buffer, 8) < 8)
                {
                  DEBUG_puts("1ippReadIO: Unable to read range value.");
                  ipp_buffer_release(buffer);
                  return (IPP_ERROR);
                }

                value->range.lower =
                    (((((buffer[0] << 8) | buffer[1]) << 8) | buffer[2]) << 8) |
                    buffer[3];
                value->range.upper =
                    (((((buffer[4] << 8) | buffer[5]) << 8) | buffer[6]) << 8) |
                    buffer[7];
                break;

            case IPP_TAG_TEXTLANG :
            case IPP_TAG_NAMELANG :
                if (n < 4)
                {
                  if (tag == IPP_TAG_TEXTLANG)
                    _cupsSetError(IPP_ERROR,
                                  _("IPP textWithLanguage value less than "
                                    "minimum 4 bytes."), 1);
                  else
                    _cupsSetError(IPP_ERROR,
                                  _("IPP nameWithLanguage value less than "
                                    "minimum 4 bytes."), 1);
                  DEBUG_printf(("1ippReadIO: bad value length %d.", n));
                  ipp_buffer_release(buffer);
                  return (IPP_ERROR);
                }

                if ((*cb)(src, buffer, n) < n)
                {
                  DEBUG_puts("1ippReadIO: Unable to read string w/language "
                             "value.");
                  ipp_buffer_release(buffer);
                  return (IPP_ERROR);
                }

                bufptr = buffer;

               /*
                * text-with-language and name-with-language are composite
                * values:
                *
                *    language-length
                *    language
                *    text-length
                *    text
                */

                n = (bufptr[0] << 8) | bufptr[1];

                if ((bufptr + 2 + n) >= (buffer + IPP_BUF_SIZE) ||
                    n >= sizeof(string))
                {
                  _cupsSetError(IPP_ERROR,
                                _("IPP language length overflows value."), 1);
                  DEBUG_printf(("1ippReadIO: bad value length %d.", n));
                  ipp_buffer_release(buffer);
                  return (IPP_ERROR);
                }

                memcpy(string, bufptr + 2, n);
                string[n] = '\0';

                value->string.language = _cupsStrAlloc((char *)string);

                bufptr += 2 + n;
                n = (bufptr[0] << 8) | bufptr[1];

                if ((bufptr + 2 + n) >= (buffer + IPP_BUF_SIZE))
                {
                  _cupsSetError(IPP_ERROR,
                                _("IPP string length overflows value."), 1);
                  DEBUG_printf(("1ippReadIO: bad value length %d.", n));
                  ipp_buffer_release(buffer);
                  return (IPP_ERROR);
                }

                bufptr[2 + n] = '\0';
                value->string.text = _cupsStrAlloc((char *)bufptr + 2);
                break;

            case IPP_TAG_BEGIN_COLLECTION :
               /*
                * Oh, boy, here comes a collection value, so read it...
                */

                value->collection = ippNew();

                if (n > 0)
                {
                  _cupsSetError(IPP_ERROR,
                                _("IPP begCollection value not 0 bytes."), 1);
                  DEBUG_puts("1ippReadIO: begCollection tag with value length "
                             "> 0.");
                  ipp_buffer_release(buffer);
                  return (IPP_ERROR);
                }

                if (ippReadIO(src, cb, 1, ipp, value->collection) == IPP_ERROR)
                {
                  DEBUG_puts("1ippReadIO: Unable to read collection value.");
                  ipp_buffer_release(buffer);
                  return (IPP_ERROR);
                }
                break;

            case IPP_TAG_END_COLLECTION :
                ipp_buffer_release(buffer);

                if (n > 0)
                {
                  _cupsSetError(IPP_ERROR,
                                _("IPP endCollection value not 0 bytes."), 1);
                  DEBUG_puts("1ippReadIO: endCollection tag with value length "
                             "> 0.");
                  return (IPP_ERROR);
                }

                DEBUG_puts("1ippReadIO: endCollection tag...");
                return (ipp->state = IPP_DATA);

            case IPP_TAG_MEMBERNAME :
               /*
                * The value the name of the member in the collection, which
                * we need to carry over...
                */

                if ((*cb)(src, buffer, n) < n)
                {
                  DEBUG_puts("1ippReadIO: Unable to read member name value.");
                  ipp_buffer_release(buffer);
                  return (IPP_ERROR);
                }

                buffer[n] = '\0';
                attr->name = _cupsStrAlloc((char *)buffer);

               /*
                * Since collection members are encoded differently than
                * regular attributes, make sure we don't start with an
                * empty value...
                */

                attr->num_values --;

                DEBUG_printf(("2ippReadIO: member name=\"%s\"", attr->name));
                break;

            default : /* Other unsupported values */
                value->unknown.length = n;
                if (n > 0)
                {
                  if ((value->unknown.data = malloc(n)) == NULL)
                  {
                    _cupsSetHTTPError(HTTP_ERROR);
                    DEBUG_puts("1ippReadIO: Unable to allocate value");
                    ipp_buffer_release(buffer);
                    return (IPP_ERROR);
                  }

                  if ((*cb)(src, value->unknown.data, n) < n)
                  {
                    DEBUG_puts("1ippReadIO: Unable to read unsupported value.");
                    ipp_buffer_release(buffer);
                    return (IPP_ERROR);
                  }
                }
                else
                  value->unknown.data = NULL;
                break;
          }

         /*
          * If blocking is disabled, stop here...
          */

          if (!blocking)
            break;
        }
        break;

    case IPP_DATA :
        break;

    default :
        break; /* anti-compiler-warning-code */
  }

  DEBUG_printf(("1ippReadIO: returning ipp->state=%d.", ipp->state));
  ipp_buffer_release(buffer);

  return (ipp->state);
}


/*
 * 'ippSetBoolean()' - Set a boolean value in an attribute.
 *
 * The @code ipp@ parameter refers to the IPP message containing the attribute that was
 * previously created using the @link ippNew@ or @link ippNewRequest@ functions.
 *
 * The @code attr@ parameter may be modified as a result of setting the value.
 *
 * The @code element@ parameter specifies which value to set from 0 to
 * @link ippGetCount(attr)@.
 *
 * @since CUPS 1.6@
 */

int                                     /* O  - 1 on success, 0 on failure */
ippSetBoolean(ipp_t           *ipp,     /* IO - IPP message */
              ipp_attribute_t **attr,   /* IO - IPP attribute */
              int             element,  /* I  - Value number (0-based) */
              int             boolvalue)/* I  - Boolean value */
{
  _ipp_value_t  *value;                 /* Current value */


 /*
  * Range check input...
  */

  if (!ipp || !attr || !*attr || (*attr)->value_tag != IPP_TAG_BOOLEAN ||
      element < 0 || element > (*attr)->num_values)
    return (0);

 /*
  * Set the value and return...
  */

  if ((value = ipp_set_value(ipp, attr, element)) != NULL)
    value->boolean = boolvalue;

  return (value != NULL);
}


/*
 * 'ippSetCollection()' - Set a collection value in an attribute.
 *
 * The @code ipp@ parameter refers to the IPP message containing the attribute that was
 * previously created using the @link ippNew@ or @link ippNewRequest@ functions.
 *
 * The @code attr@ parameter may be modified as a result of setting the value.
 *
 * The @code element@ parameter specifies which value to set from 0 to
 * @link ippGetCount(attr)@.
 *
 * @since CUPS 1.6@
 */

int                                     /* O  - 1 on success, 0 on failure */
ippSetCollection(
    ipp_t           *ipp,               /* IO - IPP message */
    ipp_attribute_t **attr,             /* IO - IPP attribute */
    int             element,            /* I  - Value number (0-based) */
    ipp_t           *colvalue)          /* I  - Collection value */
{
  _ipp_value_t  *value;                 /* Current value */


 /*
  * Range check input...
  */

  if (!ipp || !attr || !*attr || (*attr)->value_tag != IPP_TAG_BEGIN_COLLECTION ||
      element < 0 || element > (*attr)->num_values || !colvalue)
    return (0);

 /*
  * Set the value and return...
  */

  if ((value = ipp_set_value(ipp, attr, element)) != NULL)
  {
    if (value->collection)
      ippDelete(value->collection);

    value->collection = colvalue;
    colvalue->use ++;
  }

  return (value != NULL);
}


/*
 * 'ippSetDate()' - Set a date value in an attribute.
 *
 * The @code ipp@ parameter refers to the IPP message containing the attribute that was
 * previously created using the @link ippNew@ or @link ippNewRequest@ functions.
 *
 * The @code attr@ parameter may be modified as a result of setting the value.
 *
 * The @code element@ parameter specifies which value to set from 0 to
 * @link ippGetCount(attr)@.
 *
 * @since CUPS 1.6@
 */

int                                     /* O  - 1 on success, 0 on failure */
ippSetDate(ipp_t             *ipp,      /* IO - IPP message */
           ipp_attribute_t   **attr,    /* IO - IPP attribute */
           int               element,   /* I  - Value number (0-based) */
           const ipp_uchar_t *datevalue)/* I  - Date value */
{
  _ipp_value_t  *value;                 /* Current value */


 /*
  * Range check input...
  */

  if (!ipp || !attr || !*attr || (*attr)->value_tag != IPP_TAG_DATE ||
      element < 0 || element > (*attr)->num_values || !datevalue)
    return (0);

 /*
  * Set the value and return...
  */

  if ((value = ipp_set_value(ipp, attr, element)) != NULL)
    memcpy(value->date, datevalue, sizeof(value->date));

  return (value != NULL);
}


/*
 * 'ippSetGroupTag()' - Set the group tag of an attribute.
 *
 * The @code ipp@ parameter refers to the IPP message containing the attribute that was
 * previously created using the @link ippNew@ or @link ippNewRequest@ functions.
 *
 * The @code attr@ parameter may be modified as a result of setting the value.
 *
 * The @code group@ parameter specifies the IPP attribute group tag: none
 * (@code IPP_TAG_ZERO@, for member attributes), document (@code IPP_TAG_DOCUMENT@),
 * event notification (@code IPP_TAG_EVENT_NOTIFICATION@), operation
 * (@code IPP_TAG_OPERATION@), printer (@code IPP_TAG_PRINTER@), subscription
 * (@code IPP_TAG_SUBSCRIPTION@), or unsupported (@code IPP_TAG_UNSUPPORTED_GROUP@).
 *
 * @since CUPS 1.6@
 */

int                                     /* O  - 1 on success, 0 on failure */
ippSetGroupTag(
    ipp_t           *ipp,               /* IO - IPP message */
    ipp_attribute_t **attr,             /* IO - Attribute */
    ipp_tag_t       group_tag)          /* I  - Group tag */
{
 /*
  * Range check input - group tag must be 0x01 to 0x0F, per RFC 2911...
  */

  if (!ipp || !attr || group_tag < IPP_TAG_ZERO || group_tag == IPP_TAG_END ||
      group_tag >= IPP_TAG_UNSUPPORTED_VALUE)
    return (0);

 /*
  * Set the group tag and return...
  */

  (*attr)->group_tag = group_tag;

  return (1);
}


/*
 * 'ippSetInteger()' - Set an integer or enum value in an attribute.
 *
 * The @code ipp@ parameter refers to the IPP message containing the attribute that was
 * previously created using the @link ippNew@ or @link ippNewRequest@ functions.
 *
 * The @code attr@ parameter may be modified as a result of setting the value.
 *
 * The @code element@ parameter specifies which value to set from 0 to
 * @link ippGetCount(attr)@.
 *
 * @since CUPS 1.6@
 */

int                                     /* O  - 1 on success, 0 on failure */
ippSetInteger(ipp_t           *ipp,     /* IO - IPP message */
              ipp_attribute_t **attr,   /* IO - IPP attribute */
              int             element,  /* I  - Value number (0-based) */
              int             intvalue) /* I  - Integer/enum value */
{
  _ipp_value_t  *value;                 /* Current value */


 /*
  * Range check input...
  */

  if (!ipp || !attr || !*attr ||
      ((*attr)->value_tag != IPP_TAG_INTEGER && (*attr)->value_tag != IPP_TAG_ENUM) ||
      element < 0 || element > (*attr)->num_values)
    return (0);

 /*
  * Set the value and return...
  */

  if ((value = ipp_set_value(ipp, attr, element)) != NULL)
    value->integer = intvalue;

  return (value != NULL);
}


/*
 * 'ippSetName()' - Set the name of an attribute.
 *
 * The @code ipp@ parameter refers to the IPP message containing the attribute that was
 * previously created using the @link ippNew@ or @link ippNewRequest@ functions.
 *
 * The @code attr@ parameter may be modified as a result of setting the value.
 *
 * @since CUPS 1.6@
 */

int                                     /* O  - 1 on success, 0 on failure */
ippSetName(ipp_t           *ipp,        /* IO - IPP message */
           ipp_attribute_t **attr,      /* IO - IPP attribute */
           const char      *name)       /* I  - Attribute name */
{
  char  *temp;                          /* Temporary name value */


 /*
  * Range check input...
  */

  if (!ipp || !attr || !*attr)
    return (0);

 /*
  * Set the value and return...
  */

  if ((temp = _cupsStrAlloc(name)) != NULL)
  {
    if ((*attr)->name)
      _cupsStrFree((*attr)->name);

    (*attr)->name = temp;
  }

  return (temp != NULL);
}


/*
 * 'ippSetOperation()' - Set the operation ID in an IPP request message.
 *
 * The @code ipp@ parameter refers to an IPP message previously created using the
 * @link ippNew@ or @link ippNewRequest@ functions.
 *
 * @since CUPS 1.6@
 */

int                                     /* O - 1 on success, 0 on failure */
ippSetOperation(ipp_t    *ipp,          /* I - IPP request message */
                ipp_op_t op)            /* I - Operation ID */
{
 /*
  * Range check input...
  */

  if (!ipp)
    return (0);

 /*
  * Set the operation and return...
  */

  ipp->request.op.operation_id = op;

  return (1);
}


/*
 * 'ippSetRange()' - Set a rangeOfInteger value in an attribute.
 *
 * The @code ipp@ parameter refers to the IPP message containing the attribute that was
 * previously created using the @link ippNew@ or @link ippNewRequest@ functions.
 *
 * The @code attr@ parameter may be modified as a result of setting the value.
 *
 * The @code element@ parameter specifies which value to set from 0 to
 * @link ippGetCount(attr)@.
 *
 * @since CUPS 1.6@
 */

int                                     /* O  - 1 on success, 0 on failure */
ippSetRange(ipp_t           *ipp,       /* IO - IPP message */
            ipp_attribute_t **attr,     /* IO - IPP attribute */
            int             element,    /* I  - Value number (0-based) */
            int             lowervalue, /* I  - Lower bound for range */
            int             uppervalue) /* I  - Upper bound for range */
{
  _ipp_value_t  *value;                 /* Current value */


 /*
  * Range check input...
  */

  if (!ipp || !attr || !*attr || (*attr)->value_tag != IPP_TAG_RANGE ||
      element < 0 || element > (*attr)->num_values || lowervalue > uppervalue)
    return (0);

 /*
  * Set the value and return...
  */

  if ((value = ipp_set_value(ipp, attr, element)) != NULL)
  {
    value->range.lower = lowervalue;
    value->range.upper = uppervalue;
  }

  return (value != NULL);
}


/*
 * 'ippSetRequestId()' - Set the request ID in an IPP message.
 *
 * The @code ipp@ parameter refers to an IPP message previously created using the
 * @link ippNew@ or @link ippNewRequest@ functions.
 *
 * The @code request_id@ parameter must be greater than 0.
 *
 * @since CUPS 1.6@
 */

int                                     /* O - 1 on success, 0 on failure */
ippSetRequestId(ipp_t *ipp,             /* I - IPP message */
                int   request_id)       /* I - Request ID */
{
 /*
  * Range check input; not checking request_id values since ipptool wants to send
  * invalid values for conformance testing and a bad request_id does not affect the
  * encoding of a message...
  */

  if (!ipp)
    return (0);

 /*
  * Set the request ID and return...
  */

  ipp->request.any.request_id = request_id;

  return (1);
}


/*
 * 'ippSetResolution()' - Set a resolution value in an attribute.
 *
 * The @code ipp@ parameter refers to the IPP message containing the attribute that was
 * previously created using the @link ippNew@ or @link ippNewRequest@ functions.
 *
 * The @code attr@ parameter may be modified as a result of setting the value.
 *
 * The @code element@ parameter specifies which value to set from 0 to
 * @link ippGetCount(attr)@.
 *
 * @since CUPS 1.6@
 */

int                                     /* O  - 1 on success, 0 on failure */
ippSetResolution(
    ipp_t           *ipp,               /* IO - IPP message */
    ipp_attribute_t **attr,             /* IO - IPP attribute */
    int             element,            /* I  - Value number (0-based) */
    ipp_res_t       unitsvalue,         /* I  - Resolution units */
    int             xresvalue,          /* I  - Horizontal/cross feed resolution */
    int             yresvalue)          /* I  - Vertical/feed resolution */
{
  _ipp_value_t  *value;                 /* Current value */


 /*
  * Range check input...
  */

  if (!ipp || !attr || !*attr || (*attr)->value_tag != IPP_TAG_RESOLUTION ||
      element < 0 || element > (*attr)->num_values || xresvalue <= 0 || yresvalue <= 0 ||
      unitsvalue < IPP_RES_PER_INCH || unitsvalue > IPP_RES_PER_CM)
    return (0);

 /*
  * Set the value and return...
  */

  if ((value = ipp_set_value(ipp, attr, element)) != NULL)
  {
    value->resolution.units = unitsvalue;
    value->resolution.xres  = xresvalue;
    value->resolution.yres  = yresvalue;
  }

  return (value != NULL);
}


/*
 * 'ippSetState()' - Set the current state of the IPP message.
 *
 * @since CUPS 1.6@
 */

int                                     /* O - 1 on success, 0 on failure */
ippSetState(ipp_t       *ipp,           /* I - IPP message */
            ipp_state_t state)          /* I - IPP state value */
{
 /*
  * Range check input...
  */

  if (!ipp)
    return (0);

 /*
  * Set the state and return...
  */

  ipp->state   = state;
  ipp->current = NULL;

  return (1);
}


/*
 * 'ippSetStatusCode()' - Set the status code in an IPP response or event message.
 *
 * The @code ipp@ parameter refers to an IPP message previously created using the
 * @link ippNew@ or @link ippNewRequest@ functions.
 *
 * @since CUPS 1.6@
 */

int                                     /* O - 1 on success, 0 on failure */
ippSetStatusCode(ipp_t        *ipp,     /* I - IPP response or event message */
                 ipp_status_t status)   /* I - Status code */
{
 /*
  * Range check input...
  */

  if (!ipp)
    return (0);

 /*
  * Set the status code and return...
  */

  ipp->request.status.status_code = status;

  return (1);
}


/*
 * 'ippSetString()' - Set a string value in an attribute.
 *
 * The @code ipp@ parameter refers to the IPP message containing the attribute that was
 * previously created using the @link ippNew@ or @link ippNewRequest@ functions.
 *
 * The @code attr@ parameter may be modified as a result of setting the value.
 *
 * The @code element@ parameter specifies which value to set from 0 to
 * @link ippGetCount(attr)@.
 *
 * @since CUPS 1.6@
 */

int                                     /* O  - 1 on success, 0 on failure */
ippSetString(ipp_t           *ipp,      /* IO - IPP message */
             ipp_attribute_t **attr,    /* IO - IPP attribute */
             int             element,   /* I  - Value number (0-based) */
             const char      *strvalue) /* I  - String value */
{
  char          *temp;                  /* Temporary string */
  _ipp_value_t  *value;                 /* Current value */


 /*
  * Range check input...
  */

  if (!ipp || !attr || !*attr || (*attr)->value_tag != IPP_TAG_INTEGER ||
      element < 0 || element > (*attr)->num_values || !strvalue)
    return (0);

 /*
  * Set the value and return...
  */

  if ((value = ipp_set_value(ipp, attr, element)) != NULL)
  {
    if (element > 0)
      value->string.language = (*attr)->values[0].string.language;

    if ((int)((*attr)->value_tag) & IPP_TAG_COPY)
      value->string.text = (char *)strvalue;
    else if ((temp = _cupsStrAlloc(strvalue)) != NULL)
    {
      if (value->string.text)
        _cupsStrFree(value->string.text);

      value->string.text = temp;
    }
    else
      return (0);
  }

  return (value != NULL);
}


/*
 * 'ippSetValueTag()' - Set the value tag of an attribute.
 *
 * The @code ipp@ parameter refers to the IPP message containing the attribute that was
 * previously created using the @link ippNew@ or @link ippNewRequest@ functions.
 *
 * The @code attr@ parameter may be modified as a result of setting the value.
 *
 * Integer (@code IPP_TAG_INTEGER@) values can be promoted to rangeOfInteger
 * (@code IPP_TAG_RANGE@) values, the various string tags can be promoted to name
 * (@code IPP_TAG_NAME@) or nameWithLanguage (@code IPP_TAG_NAMELANG@) values, text
 * (@code IPP_TAG_TEXT@) values can be promoted to textWithLanguage
 * (@code IPP_TAG_TEXTLANG@) values, and all values can be demoted to the various
 * out-of-band value tags such as no-value (@code IPP_TAG_NOVALUE@). All other changes
 * will be rejected.
 *
 * Promoting a string attribute to nameWithLanguage or textWithLanguage adds the language
 * code in the "attributes-natural-language" attribute or, if not present, the language
 * code for the current locale.
 *
 * @since CUPS 1.6@
 */

int                                     /* O  - 1 on success, 0 on failure */
ippSetValueTag(
    ipp_t          *ipp,                /* IO - IPP message */
    ipp_attribute_t **attr,             /* IO - IPP attribute */
    ipp_tag_t       value_tag)          /* I  - Value tag */
{
  int           i;                      /* Looping var */
  _ipp_value_t  *value;                 /* Current value */
  int           integer;                /* Current integer value */
  cups_lang_t   *language;              /* Current language */
  char          code[32];               /* Language code */
  ipp_tag_t     temp_tag;               /* Temporary value tag */


 /*
  * Range check input...
  */

  if (!ipp || !attr)
    return (0);

 /*
  * If there is no change, return immediately...
  */

  if (value_tag == (*attr)->value_tag)
    return (1);

 /*
  * Otherwise implement changes as needed...
  */

  temp_tag = (ipp_tag_t)((int)((*attr)->value_tag) & IPP_TAG_MASK);

  switch (value_tag)
  {
    case IPP_TAG_UNSUPPORTED_VALUE :
    case IPP_TAG_DEFAULT :
    case IPP_TAG_UNKNOWN :
    case IPP_TAG_NOVALUE :
    case IPP_TAG_NOTSETTABLE :
    case IPP_TAG_DELETEATTR :
    case IPP_TAG_ADMINDEFINE :
       /*
        * Free any existing values...
        */

        if ((*attr)->num_values > 0)
          ipp_free_values(*attr, 0, (*attr)->num_values);

       /*
        * Set out-of-band value...
        */

        (*attr)->value_tag = value_tag;
        break;

    case IPP_TAG_RANGE :
        if (temp_tag != IPP_TAG_INTEGER)
          return (0);

        for (i = (*attr)->num_values, value = (*attr)->values;
             i > 0;
             i --, value ++)
        {
          integer            = value->integer;
          value->range.lower = value->range.upper = integer;
        }

        (*attr)->value_tag = IPP_TAG_RANGE;
        break;

    case IPP_TAG_NAME :
        if (temp_tag != IPP_TAG_KEYWORD && temp_tag != IPP_TAG_URI &&
            temp_tag != IPP_TAG_URISCHEME && temp_tag != IPP_TAG_LANGUAGE &&
            temp_tag != IPP_TAG_MIMETYPE)
          return (0);

        (*attr)->value_tag = (ipp_tag_t)(IPP_TAG_NAME | ((*attr)->value_tag & IPP_TAG_COPY));
        break;

    case IPP_TAG_NAMELANG :
    case IPP_TAG_TEXTLANG :
        if (value_tag == IPP_TAG_NAMELANG &&
            (temp_tag != IPP_TAG_NAME && temp_tag != IPP_TAG_KEYWORD &&
             temp_tag != IPP_TAG_URI && temp_tag != IPP_TAG_URISCHEME &&
             temp_tag != IPP_TAG_LANGUAGE && temp_tag != IPP_TAG_MIMETYPE))
          return (0);

        if (value_tag == IPP_TAG_TEXTLANG && temp_tag != IPP_TAG_TEXT)
          return (0);

        if (ipp->attrs && ipp->attrs->next && ipp->attrs->next->name &&
            !strcmp(ipp->attrs->next->name, "attributes-natural-language"))
        {
         /*
          * Use the language code from the IPP message...
          */

          (*attr)->values[0].string.language =
              _cupsStrAlloc(ipp->attrs->next->values[0].string.text);
        }
        else
        {
         /*
          * Otherwise, use the language code corresponding to the locale...
          */

          language = cupsLangDefault();
          (*attr)->values[0].string.language = _cupsStrAlloc(ipp_lang_code(language->language,
                                                                        code,
                                                                        sizeof(code)));
        }

        for (i = (*attr)->num_values - 1, value = (*attr)->values + 1;
             i > 0;
             i --, value ++)
          value->string.language = (*attr)->values[0].string.language;

        if ((int)(*attr)->value_tag & IPP_TAG_COPY)
        {
         /*
          * Make copies of all values...
          */

          for (i = (*attr)->num_values, value = (*attr)->values;
               i > 0;
               i --, value ++)
            value->string.text = _cupsStrAlloc(value->string.text);
        }

        (*attr)->value_tag = IPP_TAG_NAMELANG;
        break;

    case IPP_TAG_KEYWORD :
        if (temp_tag == IPP_TAG_NAME || temp_tag == IPP_TAG_NAMELANG)
          break;                        /* Silently "allow" name -> keyword */

    default :
        return (0);
  }

  return (1);
}


/*
 * 'ippSetVersion()' - Set the version number in an IPP message.
 *
 * The @code ipp@ parameter refers to an IPP message previously created using the
 * @link ippNew@ or @link ippNewRequest@ functions.
 *
 * The valid version numbers are currently 1.0, 1.1, 2.0, 2.1, and 2.2.
 *
 * @since CUPS 1.6@
 */

int                                     /* O - 1 on success, 0 on failure */
ippSetVersion(ipp_t *ipp,               /* I - IPP message */
              int   major,              /* I - Major version number (major.minor) */
              int   minor)              /* I - Minor version number (major.minor) */
{
 /*
  * Range check input...
  */

  if (!ipp || major < 0 || minor < 0)
    return (0);

 /*
  * Set the version number...
  */

  ipp->request.any.version[0] = major;
  ipp->request.any.version[1] = minor;

  return (1);
}


/*
 * 'ippTimeToDate()' - Convert from UNIX time to RFC 1903 format.
 */

const ipp_uchar_t *                     /* O - RFC-1903 date/time data */
ippTimeToDate(time_t t)                 /* I - UNIX time value */
{
  struct tm     *unixdate;              /* UNIX unixdate/time info */
  ipp_uchar_t   *date = _cupsGlobals()->ipp_date;
                                        /* RFC-1903 date/time data */


 /*
  * RFC-1903 date/time format is:
  *
  *    Byte(s)  Description
  *    -------  -----------
  *    0-1      Year (0 to 65535)
  *    2        Month (1 to 12)
  *    3        Day (1 to 31)
  *    4        Hours (0 to 23)
  *    5        Minutes (0 to 59)
  *    6        Seconds (0 to 60, 60 = "leap second")
  *    7        Deciseconds (0 to 9)
  *    8        +/- UTC
  *    9        UTC hours (0 to 11)
  *    10       UTC minutes (0 to 59)
  */

  unixdate = gmtime(&t);
  unixdate->tm_year += 1900;

  date[0]  = unixdate->tm_year >> 8;
  date[1]  = unixdate->tm_year;
  date[2]  = unixdate->tm_mon + 1;
  date[3]  = unixdate->tm_mday;
  date[4]  = unixdate->tm_hour;
  date[5]  = unixdate->tm_min;
  date[6]  = unixdate->tm_sec;
  date[7]  = 0;
  date[8]  = '+';
  date[9]  = 0;
  date[10] = 0;

  return (date);
}


/*
 * 'ippWrite()' - Write data for an IPP message to a HTTP connection.
 */

ipp_state_t                             /* O - Current state */
ippWrite(http_t *http,                  /* I - HTTP connection */
         ipp_t  *ipp)                   /* I - IPP data */
{
  DEBUG_printf(("ippWrite(http=%p, ipp=%p)", http, ipp));

  if (!http)
    return (IPP_ERROR);

  return (ippWriteIO(http, (ipp_iocb_t)httpWrite2, http->blocking, NULL, ipp));
}


/*
 * 'ippWriteFile()' - Write data for an IPP message to a file.
 *
 * @since CUPS 1.1.19/Mac OS X 10.3@
 */

ipp_state_t                             /* O - Current state */
ippWriteFile(int   fd,                  /* I - HTTP data */
             ipp_t *ipp)                /* I - IPP data */
{
  DEBUG_printf(("ippWriteFile(fd=%d, ipp=%p)", fd, ipp));

  ipp->state = IPP_IDLE;

  return (ippWriteIO(&fd, (ipp_iocb_t)ipp_write_file, 1, NULL, ipp));
}


/*
 * 'ippWriteIO()' - Write data for an IPP message.
 *
 * @since CUPS 1.2/Mac OS X 10.5@
 */

ipp_state_t                             /* O - Current state */
ippWriteIO(void       *dst,             /* I - Destination */
           ipp_iocb_t cb,               /* I - Write callback function */
           int        blocking,         /* I - Use blocking IO? */
           ipp_t      *parent,          /* I - Parent IPP message */
           ipp_t      *ipp)             /* I - IPP data */
{
  int                   i;              /* Looping var */
  int                   n;              /* Length of data */
  unsigned char         *buffer,        /* Data buffer */
                        *bufptr;        /* Pointer into buffer */
  ipp_attribute_t       *attr;          /* Current attribute */
  _ipp_value_t          *value;         /* Current value */


  DEBUG_printf(("ippWriteIO(dst=%p, cb=%p, blocking=%d, parent=%p, ipp=%p)",
                dst, cb, blocking, parent, ipp));

  if (!dst || !ipp)
    return (IPP_ERROR);

  if ((buffer = ipp_buffer_get()) == NULL)
  {
    DEBUG_puts("1ippWriteIO: Unable to get write buffer");
    return (IPP_ERROR);
  }

  switch (ipp->state)
  {
    case IPP_IDLE :
        ipp->state ++; /* Avoid common problem... */

    case IPP_HEADER :
        if (parent == NULL)
        {
         /*
          * Send the request header:
          *
          *                 Version = 2 bytes
          *   Operation/Status Code = 2 bytes
          *              Request ID = 4 bytes
          *                   Total = 8 bytes
          */

          bufptr = buffer;

          *bufptr++ = ipp->request.any.version[0];
          *bufptr++ = ipp->request.any.version[1];
          *bufptr++ = ipp->request.any.op_status >> 8;
          *bufptr++ = ipp->request.any.op_status;
          *bufptr++ = ipp->request.any.request_id >> 24;
          *bufptr++ = ipp->request.any.request_id >> 16;
          *bufptr++ = ipp->request.any.request_id >> 8;
          *bufptr++ = ipp->request.any.request_id;

          DEBUG_printf(("2ippWriteIO: version=%d.%d", buffer[0], buffer[1]));
          DEBUG_printf(("2ippWriteIO: op_status=%04x",
                        ipp->request.any.op_status));
          DEBUG_printf(("2ippWriteIO: request_id=%d",
                        ipp->request.any.request_id));

          if ((*cb)(dst, buffer, (int)(bufptr - buffer)) < 0)
          {
            DEBUG_puts("1ippWriteIO: Could not write IPP header...");
            ipp_buffer_release(buffer);
            return (IPP_ERROR);
          }
        }

       /*
        * Reset the state engine to point to the first attribute
        * in the request/response, with no current group.
        */

        ipp->state   = IPP_ATTRIBUTE;
        ipp->current = ipp->attrs;
        ipp->curtag  = IPP_TAG_ZERO;

        DEBUG_printf(("1ippWriteIO: ipp->current=%p", ipp->current));

       /*
        * If blocking is disabled, stop here...
        */

        if (!blocking)
          break;

    case IPP_ATTRIBUTE :
        while (ipp->current != NULL)
        {
         /*
          * Write this attribute...
          */

          bufptr = buffer;
          attr   = ipp->current;

          ipp->current = ipp->current->next;

          if (!parent)
          {
            if (ipp->curtag != attr->group_tag)
            {
             /*
              * Send a group tag byte...
              */

              ipp->curtag = attr->group_tag;

              if (attr->group_tag == IPP_TAG_ZERO)
                continue;

              DEBUG_printf(("2ippWriteIO: wrote group tag=%x(%s)",
                            attr->group_tag, ippTagString(attr->group_tag)));
              *bufptr++ = attr->group_tag;
            }
            else if (attr->group_tag == IPP_TAG_ZERO)
              continue;
          }

          DEBUG_printf(("1ippWriteIO: %s (%s%s)", attr->name,
                        attr->num_values > 1 ? "1setOf " : "",
                        ippTagString(attr->value_tag)));

         /*
          * Write the attribute tag and name.
          *
          * The attribute name length does not include the trailing nul
          * character in the source string.
          *
          * Collection values (parent != NULL) are written differently...
          */

          if (parent == NULL)
          {
           /*
            * Get the length of the attribute name, and make sure it won't
            * overflow the buffer...
            */

            if ((n = (int)strlen(attr->name)) > (IPP_BUF_SIZE - 8))
            {
              DEBUG_printf(("1ippWriteIO: Attribute name too long (%d)", n));
              ipp_buffer_release(buffer);
              return (IPP_ERROR);
            }

           /*
            * Write the value tag, name length, and name string...
            */

            DEBUG_printf(("2ippWriteIO: writing value tag=%x(%s)",
                          attr->value_tag, ippTagString(attr->value_tag)));
            DEBUG_printf(("2ippWriteIO: writing name=%d,\"%s\"", n,
                          attr->name));

            if (attr->value_tag > 0xff)
            {
              *bufptr++ = IPP_TAG_EXTENSION;
              *bufptr++ = attr->value_tag >> 24;
              *bufptr++ = attr->value_tag >> 16;
              *bufptr++ = attr->value_tag >> 8;
              *bufptr++ = attr->value_tag;
            }
            else
              *bufptr++ = attr->value_tag;

            *bufptr++ = n >> 8;
            *bufptr++ = n;
            memcpy(bufptr, attr->name, n);
            bufptr += n;
          }
          else
          {
           /*
            * Get the length of the attribute name, and make sure it won't
            * overflow the buffer...
            */

            if ((n = (int)strlen(attr->name)) > (IPP_BUF_SIZE - 12))
            {
              DEBUG_printf(("1ippWriteIO: Attribute name too long (%d)", n));
              ipp_buffer_release(buffer);
              return (IPP_ERROR);
            }

           /*
            * Write the member name tag, name length, name string, value tag,
            * and empty name for the collection member attribute...
            */

            DEBUG_printf(("2ippWriteIO: writing value tag=%x(memberName)",
                          IPP_TAG_MEMBERNAME));
            DEBUG_printf(("2ippWriteIO: writing name=%d,\"%s\"", n,
                          attr->name));
            DEBUG_printf(("2ippWriteIO: writing value tag=%x(%s)",
                          attr->value_tag, ippTagString(attr->value_tag)));
            DEBUG_puts("2ippWriteIO: writing name=0,\"\"");

            *bufptr++ = IPP_TAG_MEMBERNAME;
            *bufptr++ = 0;
            *bufptr++ = 0;
            *bufptr++ = n >> 8;
            *bufptr++ = n;
            memcpy(bufptr, attr->name, n);
            bufptr += n;

            if (attr->value_tag > 0xff)
            {
              *bufptr++ = IPP_TAG_EXTENSION;
              *bufptr++ = attr->value_tag >> 24;
              *bufptr++ = attr->value_tag >> 16;
              *bufptr++ = attr->value_tag >> 8;
              *bufptr++ = attr->value_tag;
            }
            else
              *bufptr++ = attr->value_tag;

            *bufptr++ = 0;
            *bufptr++ = 0;
          }

         /*
          * Now write the attribute value(s)...
          */

          switch (attr->value_tag & ~IPP_TAG_COPY)
          {
            case IPP_TAG_UNSUPPORTED_VALUE :
            case IPP_TAG_DEFAULT :
            case IPP_TAG_UNKNOWN :
            case IPP_TAG_NOVALUE :
            case IPP_TAG_NOTSETTABLE :
            case IPP_TAG_DELETEATTR :
            case IPP_TAG_ADMINDEFINE :
                *bufptr++ = 0;
                *bufptr++ = 0;
                break;

            case IPP_TAG_INTEGER :
            case IPP_TAG_ENUM :
                for (i = 0, value = attr->values;
                     i < attr->num_values;
                     i ++, value ++)
                {
                  if ((IPP_BUF_SIZE - (bufptr - buffer)) < 9)
                  {
                    if ((*cb)(dst, buffer, (int)(bufptr - buffer)) < 0)
                    {
                      DEBUG_puts("1ippWriteIO: Could not write IPP "
                                 "attribute...");
                      ipp_buffer_release(buffer);
                      return (IPP_ERROR);
                    }

                    bufptr = buffer;
                  }

                  if (i)
                  {
                   /*
                    * Arrays and sets are done by sending additional
                    * values with a zero-length name...
                    */

                    *bufptr++ = attr->value_tag;
                    *bufptr++ = 0;
                    *bufptr++ = 0;
                  }

                 /*
                  * Integers and enumerations are both 4-byte signed
                  * (twos-complement) values.
                  *
                  * Put the 2-byte length and 4-byte value into the buffer...
                  */

                  *bufptr++ = 0;
                  *bufptr++ = 4;
                  *bufptr++ = value->integer >> 24;
                  *bufptr++ = value->integer >> 16;
                  *bufptr++ = value->integer >> 8;
                  *bufptr++ = value->integer;
                }
                break;

            case IPP_TAG_BOOLEAN :
                for (i = 0, value = attr->values;
                     i < attr->num_values;
                     i ++, value ++)
                {
                  if ((IPP_BUF_SIZE - (bufptr - buffer)) < 6)
                  {
                    if ((*cb)(dst, buffer, (int)(bufptr - buffer)) < 0)
                    {
                      DEBUG_puts("1ippWriteIO: Could not write IPP "
                                 "attribute...");
                      ipp_buffer_release(buffer);
                      return (IPP_ERROR);
                    }

                    bufptr = buffer;
                  }

                  if (i)
                  {
                   /*
                    * Arrays and sets are done by sending additional
                    * values with a zero-length name...
                    */

                    *bufptr++ = attr->value_tag;
                    *bufptr++ = 0;
                    *bufptr++ = 0;
                  }

                 /*
                  * Boolean values are 1-byte; 0 = false, 1 = true.
                  *
                  * Put the 2-byte length and 1-byte value into the buffer...
                  */

                  *bufptr++ = 0;
                  *bufptr++ = 1;
                  *bufptr++ = value->boolean;
                }
                break;

            case IPP_TAG_TEXT :
            case IPP_TAG_NAME :
            case IPP_TAG_KEYWORD :
            case IPP_TAG_URI :
            case IPP_TAG_URISCHEME :
            case IPP_TAG_CHARSET :
            case IPP_TAG_LANGUAGE :
            case IPP_TAG_MIMETYPE :
                for (i = 0, value = attr->values;
                     i < attr->num_values;
                     i ++, value ++)
                {
                  if (i)
                  {
                   /*
                    * Arrays and sets are done by sending additional
                    * values with a zero-length name...
                    */

                    DEBUG_printf(("2ippWriteIO: writing value tag=%x(%s)",
                                  attr->value_tag,
                                  ippTagString(attr->value_tag)));
                    DEBUG_printf(("2ippWriteIO: writing name=0,\"\""));

                    if ((IPP_BUF_SIZE - (bufptr - buffer)) < 3)
                    {
                      if ((*cb)(dst, buffer, (int)(bufptr - buffer)) < 0)
                      {
                        DEBUG_puts("1ippWriteIO: Could not write IPP "
                                   "attribute...");
                        ipp_buffer_release(buffer);
                        return (IPP_ERROR);
                      }

                      bufptr = buffer;
                    }

                    *bufptr++ = attr->value_tag;
                    *bufptr++ = 0;
                    *bufptr++ = 0;
                  }

                  if (value->string.text != NULL)
                    n = (int)strlen(value->string.text);
                  else
                    n = 0;

                  if (n > (IPP_BUF_SIZE - 2))
                  {
                    DEBUG_printf(("1ippWriteIO: String too long (%d)", n));
                    ipp_buffer_release(buffer);
                    return (IPP_ERROR);
                  }

                  DEBUG_printf(("2ippWriteIO: writing string=%d,\"%s\"", n,
                                value->string.text));

                  if ((int)(IPP_BUF_SIZE - (bufptr - buffer)) < (n + 2))
                  {
                    if ((*cb)(dst, buffer, (int)(bufptr - buffer)) < 0)
                    {
                      DEBUG_puts("1ippWriteIO: Could not write IPP "
                                 "attribute...");
                      ipp_buffer_release(buffer);
                      return (IPP_ERROR);
                    }

                    bufptr = buffer;
                  }

                 /*
                  * All simple strings consist of the 2-byte length and
                  * character data without the trailing nul normally found
                  * in C strings.  Also, strings cannot be longer than IPP_MAX_LENGTH
                  * bytes since the 2-byte length is a signed (twos-complement)
                  * value.
                  *
                  * Put the 2-byte length and string characters in the buffer.
                  */

                  *bufptr++ = n >> 8;
                  *bufptr++ = n;

                  if (n > 0)
                  {
                    memcpy(bufptr, value->string.text, n);
                    bufptr += n;
                  }
                }
                break;

            case IPP_TAG_DATE :
                for (i = 0, value = attr->values;
                     i < attr->num_values;
                     i ++, value ++)
                {
                  if ((IPP_BUF_SIZE - (bufptr - buffer)) < 16)
                  {
                    if ((*cb)(dst, buffer, (int)(bufptr - buffer)) < 0)
                    {
                      DEBUG_puts("1ippWriteIO: Could not write IPP "
                                 "attribute...");
                      ipp_buffer_release(buffer);
                      return (IPP_ERROR);
                    }

                    bufptr = buffer;
                  }

                  if (i)
                  {
                   /*
                    * Arrays and sets are done by sending additional
                    * values with a zero-length name...
                    */

                    *bufptr++ = attr->value_tag;
                    *bufptr++ = 0;
                    *bufptr++ = 0;
                  }

                 /*
                  * Date values consist of a 2-byte length and an
                  * 11-byte date/time structure defined by RFC 1903.
                  *
                  * Put the 2-byte length and 11-byte date/time
                  * structure in the buffer.
                  */

                  *bufptr++ = 0;
                  *bufptr++ = 11;
                  memcpy(bufptr, value->date, 11);
                  bufptr += 11;
                }
                break;

            case IPP_TAG_RESOLUTION :
                for (i = 0, value = attr->values;
                     i < attr->num_values;
                     i ++, value ++)
                {
                  if ((IPP_BUF_SIZE - (bufptr - buffer)) < 14)
                  {
                    if ((*cb)(dst, buffer, (int)(bufptr - buffer)) < 0)
                    {
                      DEBUG_puts("1ippWriteIO: Could not write IPP "
                                 "attribute...");
                      ipp_buffer_release(buffer);
                      return (IPP_ERROR);
                    }

                    bufptr = buffer;
                  }

                  if (i)
                  {
                   /*
                    * Arrays and sets are done by sending additional
                    * values with a zero-length name...
                    */

                    *bufptr++ = attr->value_tag;
                    *bufptr++ = 0;
                    *bufptr++ = 0;
                  }

                 /*
                  * Resolution values consist of a 2-byte length,
                  * 4-byte horizontal resolution value, 4-byte vertical
                  * resolution value, and a 1-byte units value.
                  *
                  * Put the 2-byte length and resolution value data
                  * into the buffer.
                  */

                  *bufptr++ = 0;
                  *bufptr++ = 9;
                  *bufptr++ = value->resolution.xres >> 24;
                  *bufptr++ = value->resolution.xres >> 16;
                  *bufptr++ = value->resolution.xres >> 8;
                  *bufptr++ = value->resolution.xres;
                  *bufptr++ = value->resolution.yres >> 24;
                  *bufptr++ = value->resolution.yres >> 16;
                  *bufptr++ = value->resolution.yres >> 8;
                  *bufptr++ = value->resolution.yres;
                  *bufptr++ = value->resolution.units;
                }
                break;

            case IPP_TAG_RANGE :
                for (i = 0, value = attr->values;
                     i < attr->num_values;
                     i ++, value ++)
                {
                  if ((IPP_BUF_SIZE - (bufptr - buffer)) < 13)
                  {
                    if ((*cb)(dst, buffer, (int)(bufptr - buffer)) < 0)
                    {
                      DEBUG_puts("1ippWriteIO: Could not write IPP "
                                 "attribute...");
                      ipp_buffer_release(buffer);
                      return (IPP_ERROR);
                    }

                    bufptr = buffer;
                  }

                  if (i)
                  {
                   /*
                    * Arrays and sets are done by sending additional
                    * values with a zero-length name...
                    */

                    *bufptr++ = attr->value_tag;
                    *bufptr++ = 0;
                    *bufptr++ = 0;
                  }

                 /*
                  * Range values consist of a 2-byte length,
                  * 4-byte lower value, and 4-byte upper value.
                  *
                  * Put the 2-byte length and range value data
                  * into the buffer.
                  */

                  *bufptr++ = 0;
                  *bufptr++ = 8;
                  *bufptr++ = value->range.lower >> 24;
                  *bufptr++ = value->range.lower >> 16;
                  *bufptr++ = value->range.lower >> 8;
                  *bufptr++ = value->range.lower;
                  *bufptr++ = value->range.upper >> 24;
                  *bufptr++ = value->range.upper >> 16;
                  *bufptr++ = value->range.upper >> 8;
                  *bufptr++ = value->range.upper;
                }
                break;

            case IPP_TAG_TEXTLANG :
            case IPP_TAG_NAMELANG :
                for (i = 0, value = attr->values;
                     i < attr->num_values;
                     i ++, value ++)
                {
                  if (i)
                  {
                   /*
                    * Arrays and sets are done by sending additional
                    * values with a zero-length name...
                    */

                    if ((IPP_BUF_SIZE - (bufptr - buffer)) < 3)
                    {
                      if ((*cb)(dst, buffer, (int)(bufptr - buffer)) < 0)
                      {
                        DEBUG_puts("1ippWriteIO: Could not write IPP "
                                   "attribute...");
                        ipp_buffer_release(buffer);
                        return (IPP_ERROR);
                      }

                      bufptr = buffer;
                    }

                    *bufptr++ = attr->value_tag;
                    *bufptr++ = 0;
                    *bufptr++ = 0;
                  }

                 /*
                  * textWithLanguage and nameWithLanguage values consist
                  * of a 2-byte length for both strings and their
                  * individual lengths, a 2-byte length for the
                  * character string, the character string without the
                  * trailing nul, a 2-byte length for the character
                  * set string, and the character set string without
                  * the trailing nul.
                  */

                  n = 4;

                  if (value->string.language != NULL)
                    n += (int)strlen(value->string.language);

                  if (value->string.text != NULL)
                    n += (int)strlen(value->string.text);

                  if (n > (IPP_BUF_SIZE - 2))
                  {
                    DEBUG_printf(("1ippWriteIO: text/nameWithLanguage value "
                                  "too long (%d)", n));
                    ipp_buffer_release(buffer);
                    return (IPP_ERROR);
                  }

                  if ((int)(IPP_BUF_SIZE - (bufptr - buffer)) < (n + 2))
                  {
                    if ((*cb)(dst, buffer, (int)(bufptr - buffer)) < 0)
                    {
                      DEBUG_puts("1ippWriteIO: Could not write IPP "
                                 "attribute...");
                      ipp_buffer_release(buffer);
                      return (IPP_ERROR);
                    }

                    bufptr = buffer;
                  }

                 /* Length of entire value */
                  *bufptr++ = n >> 8;
                  *bufptr++ = n;

                 /* Length of language */
                  if (value->string.language != NULL)
                    n = (int)strlen(value->string.language);
                  else
                    n = 0;

                  *bufptr++ = n >> 8;
                  *bufptr++ = n;

                 /* Language */
                  if (n > 0)
                  {
                    memcpy(bufptr, value->string.language, n);
                    bufptr += n;
                  }

                 /* Length of text */
                  if (value->string.text != NULL)
                    n = (int)strlen(value->string.text);
                  else
                    n = 0;

                  *bufptr++ = n >> 8;
                  *bufptr++ = n;

                 /* Text */
                  if (n > 0)
                  {
                    memcpy(bufptr, value->string.text, n);
                    bufptr += n;
                  }
                }
                break;

            case IPP_TAG_BEGIN_COLLECTION :
                for (i = 0, value = attr->values;
                     i < attr->num_values;
                     i ++, value ++)
                {
                 /*
                  * Collections are written with the begin-collection
                  * tag first with a value of 0 length, followed by the
                  * attributes in the collection, then the end-collection
                  * value...
                  */

                  if ((IPP_BUF_SIZE - (bufptr - buffer)) < 5)
                  {
                    if ((*cb)(dst, buffer, (int)(bufptr - buffer)) < 0)
                    {
                      DEBUG_puts("1ippWriteIO: Could not write IPP "
                                 "attribute...");
                      ipp_buffer_release(buffer);
                      return (IPP_ERROR);
                    }

                    bufptr = buffer;
                  }

                  if (i)
                  {
                   /*
                    * Arrays and sets are done by sending additional
                    * values with a zero-length name...
                    */

                    *bufptr++ = attr->value_tag;
                    *bufptr++ = 0;
                    *bufptr++ = 0;
                  }

                 /*
                  * Write a data length of 0 and flush the buffer...
                  */

                  *bufptr++ = 0;
                  *bufptr++ = 0;

                  if ((*cb)(dst, buffer, (int)(bufptr - buffer)) < 0)
                  {
                    DEBUG_puts("1ippWriteIO: Could not write IPP "
                               "attribute...");
                    ipp_buffer_release(buffer);
                    return (IPP_ERROR);
                  }

                  bufptr = buffer;

                 /*
                  * Then write the collection attribute...
                  */

                  value->collection->state = IPP_IDLE;

                  if (ippWriteIO(dst, cb, 1, ipp,
                                 value->collection) == IPP_ERROR)
                  {
                    DEBUG_puts("1ippWriteIO: Unable to write collection value");
                    ipp_buffer_release(buffer);
                    return (IPP_ERROR);
                  }
                }
                break;

            default :
                for (i = 0, value = attr->values;
                     i < attr->num_values;
                     i ++, value ++)
                {
                  if (i)
                  {
                   /*
                    * Arrays and sets are done by sending additional
                    * values with a zero-length name...
                    */

                    if ((IPP_BUF_SIZE - (bufptr - buffer)) < 3)
                    {
                      if ((*cb)(dst, buffer, (int)(bufptr - buffer)) < 0)
                      {
                        DEBUG_puts("1ippWriteIO: Could not write IPP "
                                   "attribute...");
                        ipp_buffer_release(buffer);
                        return (IPP_ERROR);
                      }

                      bufptr = buffer;
                    }

                    *bufptr++ = attr->value_tag;
                    *bufptr++ = 0;
                    *bufptr++ = 0;
                  }

                 /*
                  * An unknown value might some new value that a
                  * vendor has come up with. It consists of a
                  * 2-byte length and the bytes in the unknown
                  * value buffer.
                  */

                  n = value->unknown.length;

                  if (n > (IPP_BUF_SIZE - 2))
                  {
                    DEBUG_printf(("1ippWriteIO: Data length too long (%d)",
                                  n));
                    ipp_buffer_release(buffer);
                    return (IPP_ERROR);
                  }

                  if ((int)(IPP_BUF_SIZE - (bufptr - buffer)) < (n + 2))
                  {
                    if ((*cb)(dst, buffer, (int)(bufptr - buffer)) < 0)
                    {
                      DEBUG_puts("1ippWriteIO: Could not write IPP "
                                 "attribute...");
                      ipp_buffer_release(buffer);
                      return (IPP_ERROR);
                    }

                    bufptr = buffer;
                  }

                 /* Length of unknown value */
                  *bufptr++ = n >> 8;
                  *bufptr++ = n;

                 /* Value */
                  if (n > 0)
                  {
                    memcpy(bufptr, value->unknown.data, n);
                    bufptr += n;
                  }
                }
                break;
          }

         /*
          * Write the data out...
          */

          if (bufptr > buffer)
          {
            if ((*cb)(dst, buffer, (int)(bufptr - buffer)) < 0)
            {
              DEBUG_puts("1ippWriteIO: Could not write IPP attribute...");
              ipp_buffer_release(buffer);
              return (IPP_ERROR);
            }

            DEBUG_printf(("2ippWriteIO: wrote %d bytes",
                          (int)(bufptr - buffer)));
          }

         /*
          * If blocking is disabled, stop here...
          */

          if (!blocking)
            break;
        }

        if (ipp->current == NULL)
        {
         /*
          * Done with all of the attributes; add the end-of-attributes
          * tag or end-collection attribute...
          */

          if (parent == NULL)
          {
            buffer[0] = IPP_TAG_END;
            n         = 1;
          }
          else
          {
            buffer[0] = IPP_TAG_END_COLLECTION;
            buffer[1] = 0; /* empty name */
            buffer[2] = 0;
            buffer[3] = 0; /* empty value */
            buffer[4] = 0;
            n         = 5;
          }

          if ((*cb)(dst, buffer, n) < 0)
          {
            DEBUG_puts("1ippWriteIO: Could not write IPP end-tag...");
            ipp_buffer_release(buffer);
            return (IPP_ERROR);
          }

          ipp->state = IPP_DATA;
        }
        break;

    case IPP_DATA :
        break;

    default :
        break; /* anti-compiler-warning-code */
  }

  ipp_buffer_release(buffer);

  return (ipp->state);
}


/*
 * 'ipp_add_attr()' - Add a new attribute to the message.
 */

static ipp_attribute_t *                /* O - New attribute */
ipp_add_attr(ipp_t      *ipp,           /* I - IPP message */
             const char *name,          /* I - Attribute name or NULL */
             ipp_tag_t  group_tag,      /* I - Group tag or IPP_TAG_ZERO */
             ipp_tag_t  value_tag,      /* I - Value tag or IPP_TAG_ZERO */
             int        num_values)     /* I - Number of values */
{
  int                   alloc_values;   /* Number of values to allocate */
  ipp_attribute_t       *attr;          /* New attribute */


  DEBUG_printf(("4ipp_add_attr(ipp=%p, name=\"%s\", group_tag=0x%x, value_tag=0x%x, "
                "num_values=%d)", ipp, name, group_tag, value_tag, num_values));

 /*
  * Range check input...
  */

  if (!ipp || num_values < 0)
    return (NULL);

 /*
  * Allocate memory, rounding the allocation up as needed...
  */

  if (num_values <= 1)
    alloc_values = 1;
  else
    alloc_values = (num_values + IPP_MAX_VALUES - 1) & ~(IPP_MAX_VALUES - 1);

  attr = calloc(sizeof(ipp_attribute_t) +
                (alloc_values - 1) * sizeof(_ipp_value_t), 1);

  if (attr)
  {
   /*
    * Initialize attribute...
    */

    if (name)
      attr->name = _cupsStrAlloc(name);

    attr->group_tag  = group_tag;
    attr->value_tag  = value_tag;
    attr->num_values = num_values;

   /*
    * Add it to the end of the linked list...
    */

    if (ipp->last)
      ipp->last->next = attr;
    else
      ipp->attrs = attr;

    ipp->prev = ipp->last;
    ipp->last = ipp->current = attr;
  }

  DEBUG_printf(("5ipp_add_attr: Returning %p", attr));

  return (attr);
}


/*
 * 'ipp_buffer_get()' - Get a read/write buffer.
 */

static unsigned char *                  /* O - Buffer */
ipp_buffer_get(void)
{
  _ipp_buffer_t         *buffer;        /* Current buffer */
  _cups_globals_t       *cg = _cupsGlobals();
                                        /* Global data */


  for (buffer = cg->ipp_buffers; buffer; buffer = buffer->next)
    if (!buffer->used)
    {
      buffer->used = 1;
      return (buffer->d);
    }

  if ((buffer = malloc(sizeof(_ipp_buffer_t))) == NULL)
    return (NULL);

  buffer->used    = 1;
  buffer->next    = cg->ipp_buffers;
  cg->ipp_buffers = buffer;

  return (buffer->d);
}


/*
 * 'ipp_buffer_release()' - Release a read/write buffer.
 */

static void
ipp_buffer_release(unsigned char *b)    /* I - Buffer to release */
{
  ((_ipp_buffer_t *)b)->used = 0;
}


/*
 * 'ipp_free_values()' - Free attribute values.
 */

static void
ipp_free_values(ipp_attribute_t *attr,  /* I - Attribute to free values from */
                int             element,/* I - First value to free */
                int             count)  /* I - Number of values to free */
{
  int           i;                      /* Looping var */
  _ipp_value_t  *value;                 /* Current value */


  DEBUG_printf(("4ipp_free_values(attr=%p, element=%d, count=%d)", attr, element, count));

  if (!(attr->value_tag & IPP_TAG_COPY))
  {
   /*
    * Free values as needed...
    */

    switch (attr->value_tag)
    {
      case IPP_TAG_TEXTLANG :
      case IPP_TAG_NAMELANG :
          if (element == 0 && count == attr->num_values && attr->values[0].string.language)
            _cupsStrFree(attr->values[0].string.language);

      case IPP_TAG_TEXT :
      case IPP_TAG_NAME :
      case IPP_TAG_RESERVED_STRING :
      case IPP_TAG_KEYWORD :
      case IPP_TAG_URI :
      case IPP_TAG_URISCHEME :
      case IPP_TAG_CHARSET :
      case IPP_TAG_LANGUAGE :
      case IPP_TAG_MIMETYPE :
          for (i = count, value = attr->values + element;
               i > 0;
               i --, value ++)
            _cupsStrFree(value->string.text);
          break;

      case IPP_TAG_DEFAULT :
      case IPP_TAG_UNKNOWN :
      case IPP_TAG_NOVALUE :
      case IPP_TAG_NOTSETTABLE :
      case IPP_TAG_DELETEATTR :
      case IPP_TAG_ADMINDEFINE :
      case IPP_TAG_INTEGER :
      case IPP_TAG_ENUM :
      case IPP_TAG_BOOLEAN :
      case IPP_TAG_DATE :
      case IPP_TAG_RESOLUTION :
      case IPP_TAG_RANGE :
          break;

      case IPP_TAG_BEGIN_COLLECTION :
          for (i = count, value = attr->values + element;
               i > 0;
               i --, value ++)
            ippDelete(value->collection);
          break;

      case IPP_TAG_STRING :
      default :
          for (i = count, value = attr->values + element;
               i > 0;
               i --, value ++)
            if (value->unknown.data)
              free(value->unknown.data);
          break;
    }
  }

 /*
  * If we are not freeing values from the end, move the remaining values up...
  */

  if ((element + count) < attr->num_values)
    memmove(attr->values + element, attr->values + element + count,
            (attr->num_values - count - element) * sizeof(_ipp_value_t));

  attr->num_values -= count;
}


/*
 * 'ipp_get_code()' - Convert a C locale/charset name into an IPP language/charset code.
 *
 * This typically converts strings of the form "ll_CC", "ll-REGION", and "CHARSET_NUMBER"
 * to "ll-cc", "ll-region", and "charset-number", respectively.
 */

static char *                           /* O - Language code string */
ipp_get_code(const char *value,         /* I - Locale/charset string */
             char       *buffer,        /* I - String buffer */
             size_t     bufsize)        /* I - Size of string buffer */
{
  char  *bufptr,                        /* Pointer into buffer */
        *bufend;                        /* End of buffer */


 /*
  * Convert values to lowercase and change _ to - as needed...
  */

  for (bufptr = buffer, bufend = buffer + bufsize - 1;
       *value && bufptr < bufend;
       value ++)
    if (*value == '_')
      *bufptr++ = '-';
    else
      *bufptr++ = _cups_tolower(*value);

  *bufptr = '\0';

 /*
  * Return the converted string...
  */

  return (buffer);
}


/*
 * 'ipp_lang_code()' - Convert a C locale name into an IPP language code.
 *
 * This typically converts strings of the form "ll_CC" and "ll-REGION" to "ll-cc" and
 * "ll-region", respectively.  It also converts the "C" (POSIX) locale to "en".
 */

static char *                           /* O - Language code string */
ipp_lang_code(const char *locale,       /* I - Locale string */
              char       *buffer,       /* I - String buffer */
              size_t     bufsize)       /* I - Size of string buffer */
{
 /*
  * Map POSIX ("C") locale to generic English, otherwise convert the locale string as-is.
  */

  if (!_cups_strcasecmp(locale, "c"))
  {
    strlcpy(buffer, "en", bufsize);
    return (buffer);
  }
  else
    return (ipp_get_code(locale, buffer, bufsize));
}


/*
 * 'ipp_length()' - Compute the length of an IPP message or collection value.
 */

static size_t                           /* O - Size of IPP message */
ipp_length(ipp_t *ipp,                  /* I - IPP message or collection */
           int   collection)            /* I - 1 if a collection, 0 otherwise */
{
  int                   i;              /* Looping var */
  size_t                bytes;          /* Number of bytes */
  ipp_attribute_t       *attr;          /* Current attribute */
  ipp_tag_t             group;          /* Current group */
  _ipp_value_t          *value;         /* Current value */


  DEBUG_printf(("3ipp_length(ipp=%p, collection=%d)", ipp, collection));

  if (!ipp)
  {
    DEBUG_puts("4ipp_length: Returning 0 bytes");
    return (0);
  }

 /*
  * Start with 8 bytes for the IPP message header...
  */

  bytes = collection ? 0 : 8;

 /*
  * Then add the lengths of each attribute...
  */

  group = IPP_TAG_ZERO;

  for (attr = ipp->attrs; attr != NULL; attr = attr->next)
  {
    if (attr->group_tag != group && !collection)
    {
      group = attr->group_tag;
      if (group == IPP_TAG_ZERO)
        continue;

      bytes ++; /* Group tag */
    }

    if (!attr->name)
      continue;

    DEBUG_printf(("5ipp_length: attr->name=\"%s\", attr->num_values=%d, "
                  "bytes=" CUPS_LLFMT, attr->name, attr->num_values, CUPS_LLCAST bytes));

    if (attr->value_tag < IPP_TAG_EXTENSION)
      bytes += attr->num_values;        /* Value tag for each value */
    else
      bytes += 5 * attr->num_values;    /* Value tag for each value */
    bytes += 2 * attr->num_values;      /* Name lengths */
    bytes += (int)strlen(attr->name);   /* Name */
    bytes += 2 * attr->num_values;      /* Value lengths */

    if (collection)
      bytes += 5;                       /* Add membername overhead */

    switch (attr->value_tag & ~IPP_TAG_COPY)
    {
      case IPP_TAG_UNSUPPORTED_VALUE :
      case IPP_TAG_DEFAULT :
      case IPP_TAG_UNKNOWN :
      case IPP_TAG_NOVALUE :
      case IPP_TAG_NOTSETTABLE :
      case IPP_TAG_DELETEATTR :
      case IPP_TAG_ADMINDEFINE :
          break;

      case IPP_TAG_INTEGER :
      case IPP_TAG_ENUM :
          bytes += 4 * attr->num_values;
          break;

      case IPP_TAG_BOOLEAN :
          bytes += attr->num_values;
          break;

      case IPP_TAG_TEXT :
      case IPP_TAG_NAME :
      case IPP_TAG_KEYWORD :
      case IPP_TAG_URI :
      case IPP_TAG_URISCHEME :
      case IPP_TAG_CHARSET :
      case IPP_TAG_LANGUAGE :
      case IPP_TAG_MIMETYPE :
          for (i = 0, value = attr->values;
               i < attr->num_values;
               i ++, value ++)
            if (value->string.text)
              bytes += strlen(value->string.text);
          break;

      case IPP_TAG_DATE :
          bytes += 11 * attr->num_values;
          break;

      case IPP_TAG_RESOLUTION :
          bytes += 9 * attr->num_values;
          break;

      case IPP_TAG_RANGE :
          bytes += 8 * attr->num_values;
          break;

      case IPP_TAG_TEXTLANG :
      case IPP_TAG_NAMELANG :
          bytes += 4 * attr->num_values;/* Charset + text length */

          for (i = 0, value = attr->values;
               i < attr->num_values;
               i ++, value ++)
          {
            if (value->string.language)
              bytes += strlen(value->string.language);

            if (value->string.text)
              bytes += strlen(value->string.text);
          }
          break;

      case IPP_TAG_BEGIN_COLLECTION :
          for (i = 0, value = attr->values;
               i < attr->num_values;
               i ++, value ++)
            bytes += ipp_length(value->collection, 1);
          break;

      default :
          for (i = 0, value = attr->values;
               i < attr->num_values;
               i ++, value ++)
            bytes += value->unknown.length;
          break;
    }
  }

 /*
  * Finally, add 1 byte for the "end of attributes" tag or 5 bytes
  * for the "end of collection" tag and return...
  */

  if (collection)
    bytes += 5;
  else
    bytes ++;

  DEBUG_printf(("4ipp_length: Returning " CUPS_LLFMT " bytes", CUPS_LLCAST bytes));

  return (bytes);
}


/*
 * 'ipp_read_http()' - Semi-blocking read on a HTTP connection...
 */

static ssize_t                          /* O - Number of bytes read */
ipp_read_http(http_t      *http,        /* I - Client connection */
              ipp_uchar_t *buffer,      /* O - Buffer for data */
              size_t      length)       /* I - Total length */
{
  int           tbytes,                 /* Total bytes read */
                bytes;                  /* Bytes read this pass */
  char          len[32];                /* Length string */


  DEBUG_printf(("7ipp_read_http(http=%p, buffer=%p, length=%d)",
                http, buffer, (int)length));

 /*
  * Loop until all bytes are read...
  */

  for (tbytes = 0, bytes = 0;
       tbytes < (int)length;
       tbytes += bytes, buffer += bytes)
  {
    DEBUG_printf(("9ipp_read_http: tbytes=%d, http->state=%d", tbytes,
                  http->state));

    if (http->state == HTTP_WAITING)
      break;

    if (http->used > 0 && http->data_encoding == HTTP_ENCODE_LENGTH)
    {
     /*
      * Do "fast read" from HTTP buffer directly...
      */

      if (http->used > (int)(length - tbytes))
        bytes = (int)(length - tbytes);
      else
        bytes = http->used;

      if (bytes == 1)
        buffer[0] = http->buffer[0];
      else
        memcpy(buffer, http->buffer, bytes);

      http->used           -= bytes;
      http->data_remaining -= bytes;

      if (http->data_remaining <= INT_MAX)
        http->_data_remaining = (int)http->data_remaining;
      else
        http->_data_remaining = INT_MAX;

      if (http->used > 0)
        memmove(http->buffer, http->buffer + bytes, http->used);

      if (http->data_remaining == 0)
      {
        if (http->data_encoding == HTTP_ENCODE_CHUNKED)
        {
         /*
          * Get the trailing CR LF after the chunk...
          */

          if (!httpGets(len, sizeof(len), http))
            return (-1);
        }

        if (http->data_encoding != HTTP_ENCODE_CHUNKED)
        {
          if (http->state == HTTP_POST_RECV)
            http->state ++;
          else
            http->state = HTTP_WAITING;
        }
      }
    }
    else
    {
     /*
      * Wait a maximum of 1 second for data...
      */

      if (!http->blocking)
      {
       /*
        * Wait up to 10 seconds for more data on non-blocking sockets...
        */

        if (!httpWait(http, 10000))
        {
         /*
          * Signal no data...
          */

          bytes = -1;
          break;
        }
      }

      if ((bytes = httpRead2(http, (char *)buffer, length - tbytes)) < 0)
      {
#ifdef WIN32
        break;
#else
        if (errno != EAGAIN && errno != EINTR)
          break;

        bytes = 0;
#endif /* WIN32 */
      }
      else if (bytes == 0)
        break;
    }
  }

 /*
  * Return the number of bytes read...
  */

  if (tbytes == 0 && bytes < 0)
    tbytes = -1;

  DEBUG_printf(("8ipp_read_http: Returning %d bytes", tbytes));

  return (tbytes);
}


/*
 * 'ipp_read_file()' - Read IPP data from a file.
 */

static ssize_t                          /* O - Number of bytes read */
ipp_read_file(int         *fd,          /* I - File descriptor */
              ipp_uchar_t *buffer,      /* O - Read buffer */
              size_t      length)       /* I - Number of bytes to read */
{
#ifdef WIN32
  return ((ssize_t)read(*fd, buffer, (unsigned)length));
#else
  return (read(*fd, buffer, length));
#endif /* WIN32 */
}


/*
 * 'ipp_set_value()' - Get the value element from an attribute, expanding it as
 *                     needed.
 */

static _ipp_value_t *                   /* O  - IPP value element or NULL on error */
ipp_set_value(ipp_t           *ipp,     /* IO - IPP message */
              ipp_attribute_t **attr,   /* IO - IPP attribute */
              int             element)  /* I  - Value number (0-based) */
{
  ipp_attribute_t       *temp,          /* New attribute pointer */
                        *current,       /* Current attribute in list */
                        *prev;          /* Previous attribute in list */
  int                   alloc_values;   /* Allocated values */


 /*
  * If we are setting an existing value element, return it...
  */

  temp = *attr;

  if (temp->num_values <= 1)
    alloc_values = 1;
  else
    alloc_values = (temp->num_values + IPP_MAX_VALUES - 1) &
                   ~(IPP_MAX_VALUES - 1);

  if (element < alloc_values)
  {
    if (element >= temp->num_values)
      temp->num_values = element + 1;

    return (temp->values + element);
  }

 /*
  * Otherwise re-allocate the attribute - we allocate in groups of IPP_MAX_VALUE
  * values when num_values > 1.
  */

  if (alloc_values < IPP_MAX_VALUES)
    alloc_values = IPP_MAX_VALUES;
  else
    alloc_values += IPP_MAX_VALUES;

  DEBUG_printf(("4ipp_set_value: Reallocating for up to %d values.",
                alloc_values));

 /*
  * Reallocate memory...
  */

  if ((temp = realloc(temp, sizeof(ipp_attribute_t) +
                            (alloc_values - 1) * sizeof(_ipp_value_t))) == NULL)
  {
    _cupsSetHTTPError(HTTP_ERROR);
    DEBUG_puts("4ipp_set_value: Unable to resize attribute.");
    return (NULL);
  }

 /*
  * Zero the new memory...
  */

  memset(temp->values + temp->num_values, 0,
         (alloc_values - temp->num_values) * sizeof(_ipp_value_t));

  if (temp != *attr)
  {
   /*
    * Reset pointers in the list...
    */

    if (ipp->current == *attr && ipp->prev)
    {
     /*
      * Use current "previous" pointer...
      */

      prev = ipp->prev;
    }
    else
    {
     /*
      * Find this attribute in the linked list...
      */

      for (prev = NULL, current = ipp->attrs;
           current && current != *attr;
           prev = current, current = current->next);

      if (!current)
      {
       /*
        * This is a serious error!
        */

        *attr = temp;
        _cupsSetError(IPP_ERROR,
                      _("IPP attribute is not a member of the message."), 1);
        DEBUG_puts("4ipp_set_value: Unable to find attribute in message.");
        return (NULL);
      }
    }

    if (prev)
      prev->next = temp;
    else
      ipp->attrs = temp;

    ipp->current = temp;
    ipp->prev    = prev;

    if (ipp->last == *attr)
      ipp->last = temp;

    *attr = temp;
  }

 /*
  * Return the value element...
  */

  if (element >= temp->num_values)
    temp->num_values = element + 1;

  return (temp->values + element);
}


/*
 * 'ipp_write_file()' - Write IPP data to a file.
 */

static ssize_t                          /* O - Number of bytes written */
ipp_write_file(int         *fd,         /* I - File descriptor */
               ipp_uchar_t *buffer,     /* I - Data to write */
               size_t      length)      /* I - Number of bytes to write */
{
#ifdef WIN32
  return ((ssize_t)write(*fd, buffer, (unsigned)length));
#else
  return (write(*fd, buffer, length));
#endif /* WIN32 */
}


/*
 * End of "$Id: ipp.c 10102 2011-11-02 23:52:39Z mike $".
 */