Run helpers in the same process group as the main process but instead

[thirdparty/squid.git] / src / HttpHeader.cc

/*
 * $Id: HttpHeader.cc,v 1.104 2005/05/06 21:34:07 wessels Exp $
 *
 * DEBUG: section 55    HTTP Header
 * AUTHOR: Alex Rousskov
 *
 * SQUID Web Proxy Cache          http://www.squid-cache.org/
 * ----------------------------------------------------------
 *
 *  Squid is the result of efforts by numerous individuals from
 *  the Internet community; see the CONTRIBUTORS file for full
 *  details.   Many organizations have provided support for Squid's
 *  development; see the SPONSORS file for full details.  Squid is
 *  Copyrighted (C) 2001 by the Regents of the University of
 *  California; see the COPYRIGHT file for full details.  Squid
 *  incorporates software developed and/or copyrighted by other
 *  sources; see the CREDITS file for full details.
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *  
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *  
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
 *
 */

#include "squid.h"
#include "Store.h"
#include "HttpHeader.h"
#include "HttpHdrContRange.h"

/*
 * On naming conventions:
 * 
 * HTTP/1.1 defines message-header as 
 * 
 * message-header = field-name ":" [ field-value ] CRLF
 * field-name     = token
 * field-value    = *( field-content | LWS )
 * 
 * HTTP/1.1 does not give a name name a group of all message-headers in a message.
 * Squid 1.1 seems to refer to that group _plus_ start-line as "headers".
 * 
 * HttpHeader is an object that represents all message-headers in a message.
 * HttpHeader does not manage start-line.
 * 
 * HttpHeader is implemented as a collection of header "entries".
 * An entry is a (field_id, field_name, field_value) triplet.
 */


/*
 * local constants and vars
 */

/*
 * A table with major attributes for every known field. 
 * We calculate name lengths and reorganize this array on start up. 
 * After reorganization, field id can be used as an index to the table.
 */
static const HttpHeaderFieldAttrs HeadersAttrs[] =
    {
        {"Accept", HDR_ACCEPT, ftStr},

        {"Accept-Charset", HDR_ACCEPT_CHARSET, ftStr},
        {"Accept-Encoding", HDR_ACCEPT_ENCODING, ftStr},
        {"Accept-Language", HDR_ACCEPT_LANGUAGE, ftStr},
        {"Accept-Ranges", HDR_ACCEPT_RANGES, ftStr},
        {"Age", HDR_AGE, ftInt},
        {"Allow", HDR_ALLOW, ftStr},
        {"Authorization", HDR_AUTHORIZATION, ftStr},	/* for now */
        {"Cache-Control", HDR_CACHE_CONTROL, ftPCc},
        {"Connection", HDR_CONNECTION, ftStr},
        {"Content-Base", HDR_CONTENT_BASE, ftStr},
        {"Content-Encoding", HDR_CONTENT_ENCODING, ftStr},
        {"Content-Language", HDR_CONTENT_LANGUAGE, ftStr},
        {"Content-Length", HDR_CONTENT_LENGTH, ftInt},
        {"Content-Location", HDR_CONTENT_LOCATION, ftStr},
        {"Content-MD5", HDR_CONTENT_MD5, ftStr},	/* for now */
        {"Content-Range", HDR_CONTENT_RANGE, ftPContRange},
        {"Content-Type", HDR_CONTENT_TYPE, ftStr},
        {"Cookie", HDR_COOKIE, ftStr},
        {"Date", HDR_DATE, ftDate_1123},
        {"ETag", HDR_ETAG, ftETag},
        {"Expires", HDR_EXPIRES, ftDate_1123},
        {"From", HDR_FROM, ftStr},
        {"Host", HDR_HOST, ftStr},
        {"If-Match", HDR_IF_MATCH, ftStr},	/* for now */
        {"If-Modified-Since", HDR_IF_MODIFIED_SINCE, ftDate_1123},
        {"If-None-Match", HDR_IF_NONE_MATCH, ftStr},	/* for now */
        {"If-Range", HDR_IF_RANGE, ftDate_1123_or_ETag},
        {"Last-Modified", HDR_LAST_MODIFIED, ftDate_1123},
        {"Link", HDR_LINK, ftStr},
        {"Location", HDR_LOCATION, ftStr},
        {"Max-Forwards", HDR_MAX_FORWARDS, ftInt},
        {"Mime-Version", HDR_MIME_VERSION, ftStr},	/* for now */
        {"Pragma", HDR_PRAGMA, ftStr},
        {"Proxy-Authenticate", HDR_PROXY_AUTHENTICATE, ftStr},
        {"Proxy-Authentication-Info", HDR_PROXY_AUTHENTICATION_INFO, ftStr},
        {"Proxy-Authorization", HDR_PROXY_AUTHORIZATION, ftStr},
        {"Proxy-Connection", HDR_PROXY_CONNECTION, ftStr},
        {"Public", HDR_PUBLIC, ftStr},
        {"Range", HDR_RANGE, ftPRange},
        {"Referer", HDR_REFERER, ftStr},
        {"Request-Range", HDR_REQUEST_RANGE, ftPRange},	/* usually matches HDR_RANGE */
        {"Retry-After", HDR_RETRY_AFTER, ftStr},	/* for now (ftDate_1123 or ftInt!) */
        {"Server", HDR_SERVER, ftStr},
        {"Set-Cookie", HDR_SET_COOKIE, ftStr},
        {"Title", HDR_TITLE, ftStr},
        {"Transfer-Encoding", HDR_TRANSFER_ENCODING, ftStr},
        {"Upgrade", HDR_UPGRADE, ftStr},	/* for now */
        {"User-Agent", HDR_USER_AGENT, ftStr},
        {"Vary", HDR_VARY, ftStr},	/* for now */
        {"Via", HDR_VIA, ftStr},	/* for now */
        {"Warning", HDR_WARNING, ftStr},	/* for now */
        {"WWW-Authenticate", HDR_WWW_AUTHENTICATE, ftStr},
        {"Authentication-Info", HDR_AUTHENTICATION_INFO, ftStr},
        {"X-Cache", HDR_X_CACHE, ftStr},
        {"X-Cache-Lookup", HDR_X_CACHE_LOOKUP, ftStr},
        {"X-Forwarded-For", HDR_X_FORWARDED_FOR, ftStr},
        {"X-Request-URI", HDR_X_REQUEST_URI, ftStr},
        {"X-Squid-Error", HDR_X_SQUID_ERROR, ftStr},
        {"Negotiate", HDR_NEGOTIATE, ftStr},
#if X_ACCELERATOR_VARY
        {"X-Accelerator-Vary", HDR_X_ACCELERATOR_VARY, ftStr},
#endif
        {"Surrogate-Capability", HDR_SURROGATE_CAPABILITY, ftStr},
        {"Surrogate-Control", HDR_SURROGATE_CONTROL, ftPSc},
        {"Front-End-Https", HDR_FRONT_END_HTTPS, ftStr},
        {"Other:", HDR_OTHER, ftStr}	/* ':' will not allow matches */
    };

static HttpHeaderFieldInfo *Headers = NULL;

http_hdr_type &operator++ (http_hdr_type &aHeader)
{
    int tmp = (int)aHeader;
    aHeader = (http_hdr_type)(++tmp);
    return aHeader;
}


/*
 * headers with field values defined as #(values) in HTTP/1.1
 * Headers that are currently not recognized, are commented out.
 */
static HttpHeaderMask ListHeadersMask;	/* set run-time using  ListHeadersArr */
static http_hdr_type ListHeadersArr[] =
    {
        HDR_ACCEPT,
        HDR_ACCEPT_CHARSET, HDR_ACCEPT_ENCODING, HDR_ACCEPT_LANGUAGE,
        HDR_ACCEPT_RANGES, HDR_ALLOW,
        HDR_CACHE_CONTROL,
        HDR_CONTENT_ENCODING,
        HDR_CONTENT_LANGUAGE,
        HDR_CONNECTION,
        HDR_IF_MATCH, HDR_IF_NONE_MATCH,
        HDR_LINK, HDR_PRAGMA,
        HDR_PROXY_CONNECTION,
        HDR_TRANSFER_ENCODING,
        HDR_UPGRADE,
        HDR_VARY,
        HDR_VIA,
        /* HDR_WARNING, */
        HDR_WWW_AUTHENTICATE,
        HDR_AUTHENTICATION_INFO,
        HDR_PROXY_AUTHENTICATION_INFO,
        /* HDR_EXPECT, HDR_TE, HDR_TRAILER */
#if X_ACCELERATOR_VARY
        HDR_X_ACCELERATOR_VARY,
#endif
        HDR_SURROGATE_CAPABILITY,
        HDR_SURROGATE_CONTROL,
        HDR_X_FORWARDED_FOR
    };

/* general-headers */
static http_hdr_type GeneralHeadersArr[] =
    {
        HDR_CACHE_CONTROL, HDR_CONNECTION, HDR_DATE, HDR_PRAGMA,
        HDR_TRANSFER_ENCODING,
        HDR_UPGRADE,
        /* HDR_TRAILER, */
        HDR_VIA,
    };

/* entity-headers */
static http_hdr_type EntityHeadersArr[] =
    {
        HDR_ALLOW, HDR_CONTENT_BASE, HDR_CONTENT_ENCODING, HDR_CONTENT_LANGUAGE,
        HDR_CONTENT_LENGTH, HDR_CONTENT_LOCATION, HDR_CONTENT_MD5,
        HDR_CONTENT_RANGE, HDR_CONTENT_TYPE, HDR_ETAG, HDR_EXPIRES, HDR_LAST_MODIFIED, HDR_LINK,
        HDR_OTHER
    };

static HttpHeaderMask ReplyHeadersMask;		/* set run-time using ReplyHeaders */
static http_hdr_type ReplyHeadersArr[] =
    {
        HDR_ACCEPT, HDR_ACCEPT_CHARSET, HDR_ACCEPT_ENCODING, HDR_ACCEPT_LANGUAGE,
        HDR_ACCEPT_RANGES, HDR_AGE,
        HDR_LOCATION, HDR_MAX_FORWARDS,
        HDR_MIME_VERSION, HDR_PUBLIC, HDR_RETRY_AFTER, HDR_SERVER, HDR_SET_COOKIE,
        HDR_VARY,
        HDR_WARNING, HDR_PROXY_CONNECTION, HDR_X_CACHE,
        HDR_X_CACHE_LOOKUP,
        HDR_X_REQUEST_URI,
#if X_ACCELERATOR_VARY
        HDR_X_ACCELERATOR_VARY,
#endif
        HDR_X_SQUID_ERROR,
        HDR_SURROGATE_CONTROL
    };

static HttpHeaderMask RequestHeadersMask;	/* set run-time using RequestHeaders */
static http_hdr_type RequestHeadersArr[] =
    {
        HDR_AUTHORIZATION, HDR_FROM, HDR_HOST,
        HDR_IF_MATCH, HDR_IF_MODIFIED_SINCE, HDR_IF_NONE_MATCH,
        HDR_IF_RANGE, HDR_MAX_FORWARDS, HDR_PROXY_CONNECTION,
        HDR_PROXY_AUTHORIZATION, HDR_RANGE, HDR_REFERER, HDR_REQUEST_RANGE,
        HDR_USER_AGENT, HDR_X_FORWARDED_FOR, HDR_SURROGATE_CAPABILITY
    };

/* header accounting */
static HttpHeaderStat HttpHeaderStats[] =
    {
        {"all"},
#if USE_HTCP
        {"HTCP reply"},
#endif
        {"request"},
        {"reply"}
    };
static int HttpHeaderStatCount = countof(HttpHeaderStats);

static int HeaderEntryParsedCount = 0;

/*
 * local routines
 */

#define assert_eid(id) assert((id) >= 0 && (id) < HDR_ENUM_END)

static HttpHeaderEntry *httpHeaderEntryCreate(http_hdr_type id, const char *name, const char *value);
static void httpHeaderEntryDestroy(HttpHeaderEntry * e);
static HttpHeaderEntry *httpHeaderEntryParseCreate(const char *field_start, const char *field_end);
static void httpHeaderNoteParsedEntry(http_hdr_type id, String value, int error);

static void httpHeaderStatInit(HttpHeaderStat * hs, const char *label);
static void httpHeaderStatDump(const HttpHeaderStat * hs, StoreEntry * e);

/*
 * Module initialization routines
 */

void
httpHeaderInitModule(void)
{
    int i;
    /* check that we have enough space for masks */
    assert(8 * sizeof(HttpHeaderMask) >= HDR_ENUM_END);
    /* all headers must be described */
    assert(countof(HeadersAttrs) == HDR_ENUM_END);

    if (!Headers)
        Headers = httpHeaderBuildFieldsInfo(HeadersAttrs, HDR_ENUM_END);

    /* create masks */
    httpHeaderMaskInit(&ListHeadersMask, 0);

    httpHeaderCalcMask(&ListHeadersMask, (const int *) ListHeadersArr, countof(ListHeadersArr));

    httpHeaderMaskInit(&ReplyHeadersMask, 0);

    httpHeaderCalcMask(&ReplyHeadersMask, (const int *) ReplyHeadersArr, countof(ReplyHeadersArr));

    httpHeaderCalcMask(&ReplyHeadersMask, (const int *) GeneralHeadersArr, countof(GeneralHeadersArr));

    httpHeaderCalcMask(&ReplyHeadersMask, (const int *) EntityHeadersArr, countof(EntityHeadersArr));

    httpHeaderMaskInit(&RequestHeadersMask, 0);

    httpHeaderCalcMask(&RequestHeadersMask, (const int *) RequestHeadersArr, countof(RequestHeadersArr));

    httpHeaderCalcMask(&RequestHeadersMask, (const int *) GeneralHeadersArr, countof(GeneralHeadersArr));

    httpHeaderCalcMask(&RequestHeadersMask, (const int *) EntityHeadersArr, countof(EntityHeadersArr));

    /* init header stats */
    assert(HttpHeaderStatCount == hoReply + 1);

    for (i = 0; i < HttpHeaderStatCount; i++)
        httpHeaderStatInit(HttpHeaderStats + i, HttpHeaderStats[i].label);

    HttpHeaderStats[hoRequest].owner_mask = &RequestHeadersMask;

    HttpHeaderStats[hoReply].owner_mask = &ReplyHeadersMask;

#if USE_HTCP

    HttpHeaderStats[hoHtcpReply].owner_mask = &ReplyHeadersMask;

#endif
    /* init dependent modules */
    httpHdrCcInitModule();

    httpHdrScInitModule();

    /* register with cache manager */
    cachemgrRegister("http_headers",
                     "HTTP Header Statistics", httpHeaderStoreReport, 0, 1);
}

void
httpHeaderCleanModule(void)
{
    httpHeaderDestroyFieldsInfo(Headers, HDR_ENUM_END);
    Headers = NULL;
    httpHdrCcCleanModule();
    httpHdrScCleanModule();
}

static void
httpHeaderStatInit(HttpHeaderStat * hs, const char *label)
{
    assert(hs);
    assert(label);
    memset(hs, 0, sizeof(HttpHeaderStat));
    hs->label = label;
    statHistEnumInit(&hs->hdrUCountDistr, 32);	/* not a real enum */
    statHistEnumInit(&hs->fieldTypeDistr, HDR_ENUM_END);
    statHistEnumInit(&hs->ccTypeDistr, CC_ENUM_END);
    statHistEnumInit(&hs->scTypeDistr, SC_ENUM_END);
}

/*
 * HttpHeader Implementation
 */

HttpHeader::HttpHeader() : owner (hoNone), len (0)
{
    httpHeaderMaskInit(&mask, 0);
}

HttpHeader::HttpHeader(http_hdr_owner_type const &anOwner) : owner (anOwner), len (0)
{
    assert(this);
    assert(anOwner > hoNone && anOwner <= hoReply);
    debug(55, 7) ("init-ing hdr: %p owner: %d\n", this, owner);
    httpHeaderMaskInit(&mask, 0);
}

HttpHeader::~HttpHeader()
{
    httpHeaderClean (this);
}

void
httpHeaderClean(HttpHeader * hdr)
{
    HttpHeaderPos pos = HttpHeaderInitPos;
    HttpHeaderEntry *e;

    assert(hdr);
    assert(hdr->owner > hoNone && hdr->owner <= hoReply);
    debug(55, 7) ("cleaning hdr: %p owner: %d\n", hdr, hdr->owner);

    /*
     * An unfortunate bug.  The hdr->entries array is initialized
     * such that count is set to zero.  httpHeaderClean() seems to
     * be called both when 'hdr' is created, and destroyed.  Thus,
     * we accumulate a large number of zero counts for 'hdr' before
     * it is ever used.  Can't think of a good way to fix it, except
     * adding a state variable that indicates whether or not 'hdr'
     * has been used.  As a hack, just never count zero-sized header
     * arrays.
     */

    if (0 != hdr->entries.count)
        statHistCount(&HttpHeaderStats[hdr->owner].hdrUCountDistr, hdr->entries.count);

    HttpHeaderStats[hdr->owner].destroyedCount++;

    HttpHeaderStats[hdr->owner].busyDestroyedCount += hdr->entries.count > 0;

    while ((e = httpHeaderGetEntry(hdr, &pos))) {
        /* tmp hack to try to avoid coredumps */

        if (e->id < 0 || e->id >= HDR_ENUM_END) {
            debug(55, 0) ("httpHeaderClean BUG: entry[%d] is invalid (%d). Ignored.\n",
                          (int) pos, e->id);
        } else {
            statHistCount(&HttpHeaderStats[hdr->owner].fieldTypeDistr, e->id);
            /* yes, this destroy() leaves us in an inconsistent state */
            httpHeaderEntryDestroy(e);
        }
    }

    hdr->entries.clean();
}

/* append entries (also see httpHeaderUpdate) */
void
httpHeaderAppend(HttpHeader * dest, const HttpHeader * src)
{
    const HttpHeaderEntry *e;
    HttpHeaderPos pos = HttpHeaderInitPos;
    assert(src && dest);
    assert(src != dest);
    debug(55, 7) ("appending hdr: %p += %p\n", dest, src);

    while ((e = httpHeaderGetEntry(src, &pos))) {
        httpHeaderAddEntry(dest, httpHeaderEntryClone(e));
    }
}

/* use fresh entries to replace old ones */
void
httpHeaderUpdate(HttpHeader * old, const HttpHeader * fresh, const HttpHeaderMask * denied_mask)
{
    assert (old);
    old->update (fresh, denied_mask);
}

void
HttpHeader::update (HttpHeader const *fresh, HttpHeaderMask const *denied_mask)
{
    const HttpHeaderEntry *e;
    HttpHeaderPos pos = HttpHeaderInitPos;
    assert(this && fresh);
    assert(this != fresh);
    debug(55, 7) ("updating hdr: %p <- %p\n", this, fresh);

    while ((e = httpHeaderGetEntry(fresh, &pos))) {
        /* deny bad guys (ok to check for HDR_OTHER) here */

        if (denied_mask && CBIT_TEST(*denied_mask, e->id))
            continue;

        httpHeaderDelByName(this, e->name.buf());

        httpHeaderAddEntry(this, httpHeaderEntryClone(e));
    }
}

/* just handy in parsing: resets and returns false */
int
httpHeaderReset(HttpHeader * hdr)
{
    http_hdr_owner_type ho;
    assert(hdr);
    ho = hdr->owner;
    httpHeaderClean(hdr);
    *hdr = HttpHeader(ho);
    return 0;
}

int
httpHeaderParse(HttpHeader * hdr, const char *header_start, const char *header_end)
{
    const char *field_ptr = header_start;
    HttpHeaderEntry *e, *e2;

    assert(hdr);
    assert(header_start && header_end);
    debug(55, 7) ("parsing hdr: (%p)\n%s\n", hdr, getStringPrefix(header_start, header_end));
    HttpHeaderStats[hdr->owner].parsedCount++;

    if (memchr(header_start, '\0', header_end - header_start)) {
        debug(55, 1) ("WARNING: HTTP header contains NULL characters {%s}\n",
                      getStringPrefix(header_start, header_end));
        return httpHeaderReset(hdr);
    }

    /* common format headers are "<name>:[ws]<value>" lines delimited by <CRLF>.
     * continuation lines start with a (single) space or tab */
    while (field_ptr < header_end) {
        const char *field_start = field_ptr;
        const char *field_end;

        do {
            const char *this_line = field_ptr;
            field_ptr = (const char *)memchr(field_ptr, '\n', header_end - field_ptr);

            if (!field_ptr)
                return httpHeaderReset(hdr);	/* missing <LF> */

            field_end = field_ptr;

            field_ptr++;	/* Move to next line */

            if (field_end > this_line && field_end[-1] == '\r') {
                field_end--;	/* Ignore CR LF */
                /* Ignore CR CR LF in relaxed mode */

                if (Config.onoff.relaxed_header_parser && field_end > this_line + 1 && field_end[-1] == '\r') {
                    debug(55, Config.onoff.relaxed_header_parser <= 0 ? 1 : 2)
                    ("WARNING: Double CR characters in HTTP header {%s}\n", getStringPrefix(field_start, field_end));
                    field_end--;
                }
            }

            /* Barf on stray CR characters */
            if (memchr(this_line, '\r', field_end - this_line)) {
                debug(55, 1) ("WARNING: suspicious CR characters in HTTP header {%s}\n",
                              getStringPrefix(field_start, field_end));

                if (Config.onoff.relaxed_header_parser) {
                    char *p = (char *) this_line;	/* XXX Warning! This destroys original header content and violates specifications somewhat */

                    while ((p = (char *)memchr(p, '\r', field_end - p)) != NULL)
                        *p++ = ' ';
                } else
                    return httpHeaderReset(hdr);
            }

            if (this_line + 1 == field_end && this_line > field_start) {
                debug(55, 1) ("WARNING: Blank continuation line in HTTP header {%s}\n",
                              getStringPrefix(header_start, header_end));
                return httpHeaderReset(hdr);
            }
        } while (field_ptr < header_end && (*field_ptr == ' ' || *field_ptr == '\t'));

        if (field_start == field_end) {
            if (field_ptr < header_end) {
                debug(55, 1) ("WARNING: unparseable HTTP header field near {%s}\n",
                              getStringPrefix(field_start, header_end));
                return httpHeaderReset(hdr);
            }

            break;		/* terminating blank line */
        }

        e = httpHeaderEntryParseCreate(field_start, field_end);

        if (NULL == e) {
            debug(55, 1) ("WARNING: unparseable HTTP header field {%s}\n",
                          getStringPrefix(field_start, field_end));
            debug(55, Config.onoff.relaxed_header_parser <= 0 ? 1 : 2)
            (" in {%s}\n", getStringPrefix(header_start, header_end));

            if (Config.onoff.relaxed_header_parser)
                continue;
            else
                return httpHeaderReset(hdr);
        }

        if (e->id == HDR_CONTENT_LENGTH && (e2 = httpHeaderFindEntry(hdr, e->id)) != NULL) {
            if (e->value.cmp(e2->value.buf()) != 0) {
                debug(55, 1) ("WARNING: found two conflicting content-length headers in {%s}\n", getStringPrefix(header_start, header_end));
                httpHeaderEntryDestroy(e);
                return httpHeaderReset(hdr);
            } else {
                debug(55, Config.onoff.relaxed_header_parser <= 0 ? 1 : 2)
                ("NOTICE: found double content-length header\n");

                if (Config.onoff.relaxed_header_parser) {
                    httpHeaderEntryDestroy(e);
                    continue;
                } else {
                    httpHeaderEntryDestroy(e);
                    return httpHeaderReset(hdr);
                }
            }
        }

        if (e->id == HDR_OTHER && stringHasWhitespace(e->name.buf())) {
            debug(55, Config.onoff.relaxed_header_parser <= 0 ? 1 : 2)
            ("WARNING: found whitespace in HTTP header name {%s}\n", getStringPrefix(field_start, field_end));

            if (!Config.onoff.relaxed_header_parser) {
                httpHeaderEntryDestroy(e);
                return httpHeaderReset(hdr);
            }
        }

        httpHeaderAddEntry(hdr, e);
    }

    return 1;			/* even if no fields where found, it is a valid header */
}

/* packs all the entries using supplied packer */
void
httpHeaderPackInto(const HttpHeader * hdr, Packer * p)
{
    HttpHeaderPos pos = HttpHeaderInitPos;
    const HttpHeaderEntry *e;
    assert(hdr && p);
    debug(55, 7) ("packing hdr: (%p)\n", hdr);
    /* pack all entries one by one */

    while ((e = httpHeaderGetEntry(hdr, &pos)))
        httpHeaderEntryPackInto(e, p);
}

/* returns next valid entry */
HttpHeaderEntry *
httpHeaderGetEntry(const HttpHeader * hdr, HttpHeaderPos * pos)
{
    assert(hdr && pos);
    assert(*pos >= HttpHeaderInitPos && *pos < (ssize_t)hdr->entries.count);

    for ((*pos)++; *pos < (ssize_t)hdr->entries.count; (*pos)++) {
        if (hdr->entries.items[*pos])
            return (HttpHeaderEntry*)hdr->entries.items[*pos];
    }

    return NULL;
}

/*
 * returns a pointer to a specified entry if any 
 * note that we return one entry so it does not make much sense to ask for
 * "list" headers
 */
HttpHeaderEntry *
httpHeaderFindEntry(const HttpHeader * hdr, http_hdr_type id)
{
    HttpHeaderPos pos = HttpHeaderInitPos;
    HttpHeaderEntry *e;
    assert(hdr);
    assert_eid(id);
    assert(!CBIT_TEST(ListHeadersMask, id));

    /* check mask first */

    if (!CBIT_TEST(hdr->mask, id))
        return NULL;

    /* looks like we must have it, do linear search */
    while ((e = httpHeaderGetEntry(hdr, &pos))) {
        if (e->id == id)
            return e;
    }

    /* hm.. we thought it was there, but it was not found */
    assert(0);

    return NULL;		/* not reached */
}

/*
 * same as httpHeaderFindEntry
 */
static HttpHeaderEntry *
httpHeaderFindLastEntry(const HttpHeader * hdr, http_hdr_type id)
{
    HttpHeaderPos pos = HttpHeaderInitPos;
    HttpHeaderEntry *e;
    HttpHeaderEntry *result = NULL;
    assert(hdr);
    assert_eid(id);
    assert(!CBIT_TEST(ListHeadersMask, id));

    /* check mask first */

    if (!CBIT_TEST(hdr->mask, id))
        return NULL;

    /* looks like we must have it, do linear search */
    while ((e = httpHeaderGetEntry(hdr, &pos))) {
        if (e->id == id)
            result = e;
    }

    assert(result);		/* must be there! */
    return result;
}

/*
 * deletes all fields with a given name if any, returns #fields deleted; 
 */
int
httpHeaderDelByName(HttpHeader * hdr, const char *name)
{
    int count = 0;
    HttpHeaderPos pos = HttpHeaderInitPos;
    HttpHeaderEntry *e;
    httpHeaderMaskInit(&hdr->mask, 0);	/* temporal inconsistency */
    debug(55, 7) ("deleting '%s' fields in hdr %p\n", name, hdr);

    while ((e = httpHeaderGetEntry(hdr, &pos))) {
        if (!e->name.caseCmp(name)) {
            httpHeaderDelAt(hdr, pos);
            count++;
        } else
            CBIT_SET(hdr->mask, e->id);
    }

    return count;
}

/* deletes all entries with a given id, returns the #entries deleted */
int
httpHeaderDelById(HttpHeader * hdr, http_hdr_type id)
{
    int count = 0;
    HttpHeaderPos pos = HttpHeaderInitPos;
    HttpHeaderEntry *e;
    debug(55, 8) ("%p del-by-id %d\n", hdr, id);
    assert(hdr);
    assert_eid(id);
    assert(id != HDR_OTHER);		/* does not make sense */

    if (!CBIT_TEST(hdr->mask, id))
        return 0;

    while ((e = httpHeaderGetEntry(hdr, &pos))) {
        if (e->id == id) {
            httpHeaderDelAt(hdr, pos);
            count++;
        }
    }

    CBIT_CLR(hdr->mask, id);
    assert(count);
    return count;
}

/*
 * deletes an entry at pos and leaves a gap; leaving a gap makes it
 * possible to iterate(search) and delete fields at the same time
 */
void
httpHeaderDelAt(HttpHeader * hdr, HttpHeaderPos pos)
{
    HttpHeaderEntry *e;
    assert(pos >= HttpHeaderInitPos && pos < (ssize_t)hdr->entries.count);
    e = (HttpHeaderEntry*)hdr->entries.items[pos];
    hdr->entries.items[pos] = NULL;
    /* decrement header length, allow for ": " and crlf */
    hdr->len -= e->name.size() + 2 + e->value.size() + 2;
    assert(hdr->len >= 0);
    httpHeaderEntryDestroy(e);
}


/* appends an entry;
 * does not call httpHeaderEntryClone() so one should not reuse "*e"
 */
void
httpHeaderAddEntry(HttpHeader * hdr, HttpHeaderEntry * e)
{
    assert(hdr && e);
    assert_eid(e->id);

    debugs(55, 7, hdr << " adding entry: " << e->id << " at " <<
           hdr->entries.count);

    if (CBIT_TEST(hdr->mask, e->id))
        Headers[e->id].stat.repCount++;
    else
        CBIT_SET(hdr->mask, e->id);

    hdr->entries.push_back(e);

    /* increment header length, allow for ": " and crlf */
    hdr->len += e->name.size() + 2 + e->value.size() + 2;
}

/* return a list of entries with the same id separated by ',' and ws */
String
httpHeaderGetList(const HttpHeader * hdr, http_hdr_type id)
{
    HttpHeaderEntry *e;
    HttpHeaderPos pos = HttpHeaderInitPos;
    debug(55, 6) ("%p: joining for id %d\n", hdr, id);
    /* only fields from ListHeaders array can be "listed" */
    assert(CBIT_TEST(ListHeadersMask, id));

    if (!CBIT_TEST(hdr->mask, id))
        return String();

    String s;

    while ((e = httpHeaderGetEntry(hdr, &pos))) {
        if (e->id == id)
            strListAdd(&s, e->value.buf(), ',');
    }

    /*
     * note: we might get an empty (len==0) string if there was an "empty"
     * header; we must not get a NULL string though.
     */
    assert(s.buf());

    /* temporary warning: remove it! @?@ @?@ @?@ */
    if (!s.size())
        debug(55, 3) ("empty list header: %s (%d)\n", Headers[id].name.buf(), id);

    debug(55, 6) ("%p: joined for id %d: %s\n", hdr, id, s.buf());

    return s;
}

/* return a string or list of entries with the same id separated by ',' and ws */
String
httpHeaderGetStrOrList(const HttpHeader * hdr, http_hdr_type id)
{
    HttpHeaderEntry *e;

    if (CBIT_TEST(ListHeadersMask, id))
        return httpHeaderGetList(hdr, id);

    if ((e = httpHeaderFindEntry(hdr, id)))
        return e->value;

    return String();
}

/*
 * Returns the value of the specified header.
 */
String
httpHeaderGetByName(const HttpHeader * hdr, const char *name)
{
    http_hdr_type id;
    HttpHeaderPos pos = HttpHeaderInitPos;
    HttpHeaderEntry *e;

    assert(hdr);
    assert(name);

    /* First try the quick path */
    id = httpHeaderIdByNameDef(name, strlen(name));

    if (id != -1)
        return httpHeaderGetStrOrList(hdr, id);

    String result;

    /* Sorry, an unknown header name. Do linear search */
    while ((e = httpHeaderGetEntry(hdr, &pos))) {
        if (e->id == HDR_OTHER && e->name.caseCmp(name) == 0) {
            strListAdd(&result, e->value.buf(), ',');
        }
    }

    return result;
}

/*
 * Returns a the value of the specified list member, if any.
 */
String
httpHeaderGetByNameListMember(const HttpHeader * hdr, const char *name, const char *member, const char separator)
{
    String header;
    const char *pos = NULL;
    const char *item;
    int ilen;
    int mlen = strlen(member);

    assert(hdr);
    assert(name);

    header = httpHeaderGetByName(hdr, name);

    String result;

    while (strListGetItem(&header, separator, &item, &ilen, &pos)) {
        if (strncmp(item, member, mlen) == 0 && item[mlen] == '=') {
            result.append(item + mlen + 1, ilen - mlen - 1);
            break;
        }
    }

    return result;
}

/*
 * returns a the value of the specified list member, if any.
 */
String
httpHeaderGetListMember(const HttpHeader * hdr, http_hdr_type id, const char *member, const char separator)
{
    String header;
    const char *pos = NULL;
    const char *item;
    int ilen;
    int mlen = strlen(member);

    assert(hdr);
    assert(id >= 0);

    header = httpHeaderGetStrOrList(hdr, id);
    String result;

    while (strListGetItem(&header, separator, &item, &ilen, &pos)) {
        if (strncmp(item, member, mlen) == 0 && item[mlen] == '=') {
            result.append(item + mlen + 1, ilen - mlen - 1);
            break;
        }
    }

    header.clean();
    return result;
}

/* test if a field is present */
int
httpHeaderHas(const HttpHeader * hdr, http_hdr_type id)
{
    assert(hdr);
    assert_eid(id);
    assert(id != HDR_OTHER);
    debug(55, 7) ("%p lookup for %d\n", hdr, id);
    return CBIT_TEST(hdr->mask, id);
}

void
httpHeaderPutInt(HttpHeader * hdr, http_hdr_type id, int number)
{
    assert_eid(id);
    assert(Headers[id].type == ftInt);	/* must be of an appropriate type */
    assert(number >= 0);
    httpHeaderAddEntry(hdr, httpHeaderEntryCreate(id, NULL, xitoa(number)));
}

void
httpHeaderPutTime(HttpHeader * hdr, http_hdr_type id, time_t htime)
{
    assert_eid(id);
    assert(Headers[id].type == ftDate_1123);	/* must be of an appropriate type */
    assert(htime >= 0);
    httpHeaderAddEntry(hdr, httpHeaderEntryCreate(id, NULL, mkrfc1123(htime)));
}

void
httpHeaderPutStr(HttpHeader * hdr, http_hdr_type id, const char *str)
{
    assert_eid(id);
    assert(Headers[id].type == ftStr);	/* must be of an appropriate type */
    assert(str);
    httpHeaderAddEntry(hdr, httpHeaderEntryCreate(id, NULL, str));
}

void
httpHeaderPutAuth(HttpHeader * hdr, const char *auth_scheme, const char *realm)
{
    assert(hdr && auth_scheme && realm);
    httpHeaderPutStrf(hdr, HDR_WWW_AUTHENTICATE, "%s realm=\"%s\"", auth_scheme, realm);
}

void
httpHeaderPutCc(HttpHeader * hdr, const HttpHdrCc * cc)
{
    MemBuf mb;
    Packer p;
    assert(hdr && cc);
    /* remove old directives if any */
    httpHeaderDelById(hdr, HDR_CACHE_CONTROL);
    /* pack into mb */
    memBufDefInit(&mb);
    packerToMemInit(&p, &mb);
    httpHdrCcPackInto(cc, &p);
    /* put */
    httpHeaderAddEntry(hdr, httpHeaderEntryCreate(HDR_CACHE_CONTROL, NULL, mb.buf));
    /* cleanup */
    packerClean(&p);
    memBufClean(&mb);
}

void
httpHeaderPutContRange(HttpHeader * hdr, const HttpHdrContRange * cr)
{
    MemBuf mb;
    Packer p;
    assert(hdr && cr);
    /* remove old directives if any */
    httpHeaderDelById(hdr, HDR_CONTENT_RANGE);
    /* pack into mb */
    memBufDefInit(&mb);
    packerToMemInit(&p, &mb);
    httpHdrContRangePackInto(cr, &p);
    /* put */
    httpHeaderAddEntry(hdr, httpHeaderEntryCreate(HDR_CONTENT_RANGE, NULL, mb.buf));
    /* cleanup */
    packerClean(&p);
    memBufClean(&mb);
}

void
httpHeaderPutRange(HttpHeader * hdr, const HttpHdrRange * range)
{
    MemBuf mb;
    Packer p;
    assert(hdr && range);
    /* remove old directives if any */
    httpHeaderDelById(hdr, HDR_RANGE);
    /* pack into mb */
    memBufDefInit(&mb);
    packerToMemInit(&p, &mb);
    range->packInto(&p);
    /* put */
    httpHeaderAddEntry(hdr, httpHeaderEntryCreate(HDR_RANGE, NULL, mb.buf));
    /* cleanup */
    packerClean(&p);
    memBufClean(&mb);
}

void
httpHeaderPutSc(HttpHeader *hdr, const HttpHdrSc *sc)
{
    MemBuf mb;
    Packer p;
    assert(hdr && sc);
    /* remove old directives if any */
    httpHeaderDelById(hdr, HDR_RANGE);
    /* pack into mb */
    memBufDefInit(&mb);
    packerToMemInit(&p, &mb);
    httpHdrScPackInto(sc, &p);
    /* put */
    httpHeaderAddEntry(hdr, httpHeaderEntryCreate(HDR_SURROGATE_CONTROL, NULL, mb.buf));
    /* cleanup */
    packerClean(&p);
    memBufClean(&mb);
}

/* add extension header (these fields are not parsed/analyzed/joined, etc.) */
void
httpHeaderPutExt(HttpHeader * hdr, const char *name, const char *value)
{
    assert(name && value);
    debug(55, 8) ("%p adds ext entry '%s: %s'\n", hdr, name, value);
    httpHeaderAddEntry(hdr, httpHeaderEntryCreate(HDR_OTHER, name, value));
}

int
httpHeaderEntryGetInt (const HttpHeaderEntry * e)
{
    int value = -1;
    int ok;
    assert (e);
    assert_eid (e->id);
    assert (Headers[e->id].type == ftInt);
    ok = httpHeaderParseInt(e->value.buf(), &value);
    httpHeaderNoteParsedEntry(e->id, e->value, !ok);
    /* XXX: Should we check ok - ie
     * return ok ? -1 : value;
     */
    return value;
}

int
httpHeaderGetInt(const HttpHeader * hdr, http_hdr_type id)
{
    assert_eid(id);
    assert(Headers[id].type == ftInt);	/* must be of an appropriate type */
    HttpHeaderEntry *e;

    if ((e = httpHeaderFindEntry(hdr, id)))
        return httpHeaderEntryGetInt (e);

    return -1;
}

time_t
httpHeaderGetTime(const HttpHeader * hdr, http_hdr_type id)
{
    HttpHeaderEntry *e;
    time_t value = -1;
    assert_eid(id);
    assert(Headers[id].type == ftDate_1123);	/* must be of an appropriate type */

    if ((e = httpHeaderFindEntry(hdr, id))) {
        value = parse_rfc1123(e->value.buf());
        httpHeaderNoteParsedEntry(e->id, e->value, value < 0);
    }

    return value;
}

/* sync with httpHeaderGetLastStr */
const char *
httpHeaderGetStr(const HttpHeader * hdr, http_hdr_type id)
{
    HttpHeaderEntry *e;
    assert_eid(id);
    assert(Headers[id].type == ftStr);	/* must be of an appropriate type */

    if ((e = httpHeaderFindEntry(hdr, id))) {
        httpHeaderNoteParsedEntry(e->id, e->value, 0);	/* no errors are possible */
        return e->value.buf();
    }

    return NULL;
}

/* unusual */
const char *
httpHeaderGetLastStr(const HttpHeader * hdr, http_hdr_type id)
{
    HttpHeaderEntry *e;
    assert_eid(id);
    assert(Headers[id].type == ftStr);	/* must be of an appropriate type */

    if ((e = httpHeaderFindLastEntry(hdr, id))) {
        httpHeaderNoteParsedEntry(e->id, e->value, 0);	/* no errors are possible */
        return e->value.buf();
    }

    return NULL;
}

HttpHdrCc *
httpHeaderGetCc(const HttpHeader * hdr)
{
    HttpHdrCc *cc;
    String s;

    if (!CBIT_TEST(hdr->mask, HDR_CACHE_CONTROL))
        return NULL;

    s = httpHeaderGetList(hdr, HDR_CACHE_CONTROL);

    cc = httpHdrCcParseCreate(&s);

    HttpHeaderStats[hdr->owner].ccParsedCount++;

    if (cc)
        httpHdrCcUpdateStats(cc, &HttpHeaderStats[hdr->owner].ccTypeDistr);

    httpHeaderNoteParsedEntry(HDR_CACHE_CONTROL, s, !cc);

    s.clean();

    return cc;
}

HttpHdrRange *
httpHeaderGetRange(const HttpHeader * hdr)
{
    HttpHdrRange *r = NULL;
    HttpHeaderEntry *e;
    /* some clients will send "Request-Range" _and_ *matching* "Range"
     * who knows, some clients might send Request-Range only;
     * this "if" should work correctly in both cases;
     * hopefully no clients send mismatched headers! */

    if ((e = httpHeaderFindEntry(hdr, HDR_RANGE)) ||
            (e = httpHeaderFindEntry(hdr, HDR_REQUEST_RANGE))) {
        r = HttpHdrRange::ParseCreate(&e->value);
        httpHeaderNoteParsedEntry(e->id, e->value, !r);
    }

    return r;
}

HttpHdrSc *
httpHeaderGetSc(const HttpHeader *hdr)
{
    if (!CBIT_TEST(hdr->mask, HDR_SURROGATE_CONTROL))
        return NULL;

    String s (httpHeaderGetList(hdr, HDR_SURROGATE_CONTROL));

    HttpHdrSc *sc = httpHdrScParseCreate(&s);

    HttpHeaderStats[hdr->owner].ccParsedCount++;

    if (sc)
        httpHdrScUpdateStats(sc, &HttpHeaderStats[hdr->owner].scTypeDistr);

    httpHeaderNoteParsedEntry(HDR_SURROGATE_CONTROL, s, !sc);

    return sc;
}

HttpHdrContRange *
httpHeaderGetContRange(const HttpHeader * hdr)
{
    HttpHdrContRange *cr = NULL;
    HttpHeaderEntry *e;

    if ((e = httpHeaderFindEntry(hdr, HDR_CONTENT_RANGE))) {
        cr = httpHdrContRangeParseCreate(e->value.buf());
        httpHeaderNoteParsedEntry(e->id, e->value, !cr);
    }

    return cr;
}

const char *
httpHeaderGetAuth(const HttpHeader * hdr, http_hdr_type id, const char *auth_scheme)
{
    const char *field;
    int l;
    assert(hdr && auth_scheme);
    field = httpHeaderGetStr(hdr, id);

    if (!field)			/* no authorization field */
        return NULL;

    l = strlen(auth_scheme);

    if (!l || strncasecmp(field, auth_scheme, l))	/* wrong scheme */
        return NULL;

    field += l;

    if (!xisspace(*field))	/* wrong scheme */
        return NULL;

    /* skip white space */
    field += xcountws(field);

    if (!*field)		/* no authorization cookie */
        return NULL;

    return base64_decode(field);
}

ETag
httpHeaderGetETag(const HttpHeader * hdr, http_hdr_type id)
{
    ETag etag =
        {NULL, -1};
    HttpHeaderEntry *e;
    assert(Headers[id].type == ftETag);		/* must be of an appropriate type */

    if ((e = httpHeaderFindEntry(hdr, id)))
        etagParseInit(&etag, e->value.buf());

    return etag;
}

TimeOrTag
httpHeaderGetTimeOrTag(const HttpHeader * hdr, http_hdr_type id)
{
    TimeOrTag tot;
    HttpHeaderEntry *e;
    assert(Headers[id].type == ftDate_1123_or_ETag);	/* must be of an appropriate type */
    memset(&tot, 0, sizeof(tot));

    if ((e = httpHeaderFindEntry(hdr, id))) {
        const char *str = e->value.buf();
        /* try as an ETag */

        if (etagParseInit(&tot.tag, str)) {
            tot.valid = tot.tag.str != NULL;
            tot.time = -1;
        } else {
            /* or maybe it is time? */
            tot.time = parse_rfc1123(str);
            tot.valid = tot.time >= 0;
            tot.tag.str = NULL;
        }
    }

    assert(tot.time < 0 || !tot.tag.str);	/* paranoid */
    return tot;
}

/*
 * HttpHeaderEntry
 */

static HttpHeaderEntry *
httpHeaderEntryCreate(http_hdr_type id, const char *name, const char *value)
{
    HttpHeaderEntry *e;
    assert_eid(id);
    e = new HttpHeaderEntry;
    e->id = id;

    if (id != HDR_OTHER)
        e->name = Headers[id].name;
    else
        e->name = name;

    e->value = value;

    Headers[id].stat.aliveCount++;

    debug(55, 9) ("created entry %p: '%s: %s'\n", e, e->name.buf(), e->value.buf());

    return e;
}

static void
httpHeaderEntryDestroy(HttpHeaderEntry * e)
{
    assert(e);
    assert_eid(e->id);
    debug(55, 9) ("destroying entry %p: '%s: %s'\n", e, e->name.buf(), e->value.buf());
    /* clean name if needed */

    if (e->id == HDR_OTHER)
        e->name.clean();

    e->value.clean();

    assert(Headers[e->id].stat.aliveCount);

    Headers[e->id].stat.aliveCount--;

    e->id = HDR_BAD_HDR;

    delete e;
}

/* parses and inits header entry, returns new entry on success */
static HttpHeaderEntry *
httpHeaderEntryParseCreate(const char *field_start, const char *field_end)
{
    HttpHeaderEntry *e;
    http_hdr_type id;
    /* note: name_start == field_start */
    const char *name_end = (const char *)memchr(field_start, ':', field_end - field_start);
    int name_len = name_end ? name_end - field_start : 0;
    const char *value_start = field_start + name_len + 1;	/* skip ':' */
    /* note: value_end == field_end */

    HeaderEntryParsedCount++;

    /* do we have a valid field name within this field? */

    if (!name_len || name_end > field_end)
        return NULL;

    if (name_len > 65534) {
        /* String must be LESS THAN 64K and it adds a terminating NULL */
        debug(55, 1) ("WARNING: ignoring header name of %d bytes\n", name_len);
        return NULL;
    }

    if (Config.onoff.relaxed_header_parser && xisspace(field_start[name_len - 1])) {
        debug(55, Config.onoff.relaxed_header_parser <= 0 ? 1 : 2)
        ("NOTICE: Whitespace after header name in '%s'\n", getStringPrefix(field_start, field_end));

        while (name_len > 0 && xisspace(field_start[name_len - 1]))
            name_len--;

        if (!name_len)
            return NULL;
    }

    /* now we know we can parse it */
    e = new HttpHeaderEntry;

    debug(55, 9) ("creating entry %p: near '%s'\n", e, getStringPrefix(field_start, field_end));

    /* is it a "known" field? */
    id = httpHeaderIdByName(field_start, name_len, Headers, HDR_ENUM_END);

    if (id < 0)
        id = HDR_OTHER;

    assert_eid(id);

    e->id = id;

    /* set field name */
    if (id == HDR_OTHER)
        e->name.limitInit(field_start, name_len);
    else
        e->name = Headers[id].name;

    /* trim field value */
    while (value_start < field_end && xisspace(*value_start))
        value_start++;

    while (value_start < field_end && xisspace(field_end[-1]))
        field_end--;

    if (field_end - value_start > 65534) {
        /* String must be LESS THAN 64K and it adds a terminating NULL */
        debug(55, 1) ("WARNING: ignoring '%s' header of %d bytes\n",
                      e->name.buf(), (int) (field_end - value_start));

        if (e->id == HDR_OTHER)
            e->name.clean();

        delete e;

        return NULL;
    }

    /* set field value */
    e->value.limitInit(value_start, field_end - value_start);

    Headers[id].stat.seenCount++;

    Headers[id].stat.aliveCount++;

    debug(55, 9) ("created entry %p: '%s: %s'\n", e, e->name.buf(), e->value.buf());

    return e;
}

HttpHeaderEntry *
httpHeaderEntryClone(const HttpHeaderEntry * e)
{
    return httpHeaderEntryCreate(e->id, e->name.buf(), e->value.buf());
}

void
httpHeaderEntryPackInto(const HttpHeaderEntry * e, Packer * p)
{
    assert(e && p);
    packerAppend(p, e->name.buf(), e->name.size());
    packerAppend(p, ": ", 2);
    packerAppend(p, e->value.buf(), e->value.size());
    packerAppend(p, "\r\n", 2);
}

static void
httpHeaderNoteParsedEntry(http_hdr_type id, String context, int error)
{
    Headers[id].stat.parsCount++;

    if (error) {
        Headers[id].stat.errCount++;
        debug(55, 2) ("cannot parse hdr field: '%s: %s'\n",
                      Headers[id].name.buf(), context.buf());
    }
}

/*
 * Reports
 */

/* tmp variable used to pass stat info to dumpers */
extern const HttpHeaderStat *dump_stat;		/* argh! */
const HttpHeaderStat *dump_stat = NULL;

static void
httpHeaderFieldStatDumper(StoreEntry * sentry, int idx, double val, double size, int count)
{
    const int id = (int) val;
    const int valid_id = id >= 0 && id < HDR_ENUM_END;
    const char *name = valid_id ? Headers[id].name.buf() : "INVALID";
    int visible = count > 0;
    /* for entries with zero count, list only those that belong to current type of message */

    if (!visible && valid_id && dump_stat->owner_mask)
        visible = CBIT_TEST(*dump_stat->owner_mask, id);

    if (visible)
        storeAppendPrintf(sentry, "%2d\t %-20s\t %5d\t %6.2f\n",
                          id, name, count, xdiv(count, dump_stat->busyDestroyedCount));
}

static void
httpHeaderFldsPerHdrDumper(StoreEntry * sentry, int idx, double val, double size, int count)
{
    if (count)
        storeAppendPrintf(sentry, "%2d\t %5d\t %5d\t %6.2f\n",
                          idx, (int) val, count,
                          xpercent(count, dump_stat->destroyedCount));
}


static void
httpHeaderStatDump(const HttpHeaderStat * hs, StoreEntry * e)
{
    assert(hs && e);

    dump_stat = hs;
    storeAppendPrintf(e, "\nHeader Stats: %s\n", hs->label);
    storeAppendPrintf(e, "\nField type distribution\n");
    storeAppendPrintf(e, "%2s\t %-20s\t %5s\t %6s\n",
                      "id", "name", "count", "#/header");
    statHistDump(&hs->fieldTypeDistr, e, httpHeaderFieldStatDumper);
    storeAppendPrintf(e, "\nCache-control directives distribution\n");
    storeAppendPrintf(e, "%2s\t %-20s\t %5s\t %6s\n",
                      "id", "name", "count", "#/cc_field");
    statHistDump(&hs->ccTypeDistr, e, httpHdrCcStatDumper);
    storeAppendPrintf(e, "\nSurrogate-control directives distribution\n");
    storeAppendPrintf(e, "%2s\t %-20s\t %5s\t %6s\n",
                      "id", "name", "count", "#/sc_field");
    statHistDump(&hs->scTypeDistr, e, httpHdrScStatDumper);
    storeAppendPrintf(e, "\nNumber of fields per header distribution\n");
    storeAppendPrintf(e, "%2s\t %-5s\t %5s\t %6s\n",
                      "id", "#flds", "count", "%total");
    statHistDump(&hs->hdrUCountDistr, e, httpHeaderFldsPerHdrDumper);
    dump_stat = NULL;
}

void
httpHeaderStoreReport(StoreEntry * e)
{
    int i;
    http_hdr_type ht;
    assert(e);

    HttpHeaderStats[0].parsedCount =
        HttpHeaderStats[hoRequest].parsedCount + HttpHeaderStats[hoReply].parsedCount;
    HttpHeaderStats[0].ccParsedCount =
        HttpHeaderStats[hoRequest].ccParsedCount + HttpHeaderStats[hoReply].ccParsedCount;
    HttpHeaderStats[0].destroyedCount =
        HttpHeaderStats[hoRequest].destroyedCount + HttpHeaderStats[hoReply].destroyedCount;
    HttpHeaderStats[0].busyDestroyedCount =
        HttpHeaderStats[hoRequest].busyDestroyedCount + HttpHeaderStats[hoReply].busyDestroyedCount;

    for (i = 1; i < HttpHeaderStatCount; i++) {
        httpHeaderStatDump(HttpHeaderStats + i, e);
        storeAppendPrintf(e, "%s\n", "<br>");
    }

    /* field stats for all messages */
    storeAppendPrintf(e, "\nHttp Fields Stats (replies and requests)\n");

    storeAppendPrintf(e, "%2s\t %-20s\t %5s\t %6s\t %6s\n",
                      "id", "name", "#alive", "%err", "%repeat");

    for (ht = (http_hdr_type)0; ht < HDR_ENUM_END; ++ht) {
        HttpHeaderFieldInfo *f = Headers + ht;
        storeAppendPrintf(e, "%2d\t %-20s\t %5d\t %6.3f\t %6.3f\n",
                          f->id, f->name.buf(), f->stat.aliveCount,
                          xpercent(f->stat.errCount, f->stat.parsCount),
                          xpercent(f->stat.repCount, f->stat.seenCount));
    }

    storeAppendPrintf(e, "Headers Parsed: %d + %d = %d\n",
                      HttpHeaderStats[hoRequest].parsedCount,
                      HttpHeaderStats[hoReply].parsedCount,
                      HttpHeaderStats[0].parsedCount);
    storeAppendPrintf(e, "Hdr Fields Parsed: %d\n", HeaderEntryParsedCount);
}

http_hdr_type
httpHeaderIdByName(const char *name, int name_len, const HttpHeaderFieldInfo * info, int end)
{
    int i;

    for (i = 0; i < end; ++i) {
        if (name_len >= 0 && name_len != info[i].name.size())
            continue;

        if (!strncasecmp(name, info[i].name.buf(),
                         name_len < 0 ? info[i].name.size() + 1 : name_len))
            return info[i].id;
    }

    return HDR_BAD_HDR;
}

http_hdr_type
httpHeaderIdByNameDef(const char *name, int name_len)
{
    if (!Headers)
        Headers = httpHeaderBuildFieldsInfo(HeadersAttrs, HDR_ENUM_END);

    return httpHeaderIdByName(name, name_len, Headers, HDR_ENUM_END);
}

const char *
httpHeaderNameById(int id)
{
    if (!Headers)
        Headers = httpHeaderBuildFieldsInfo(HeadersAttrs, HDR_ENUM_END);

    assert(id >= 0 && id < HDR_ENUM_END);

    return Headers[id].name.buf();
}

int
httpHeaderHasListMember(const HttpHeader * hdr, http_hdr_type id, const char *member, const char separator)
{
    int result = 0;
    const char *pos = NULL;
    const char *item;
    int ilen;
    int mlen = strlen(member);

    assert(hdr);
    assert(id >= 0);

    String header (httpHeaderGetStrOrList(hdr, id));

    while (strListGetItem(&header, separator, &item, &ilen, &pos)) {
        if (strncmp(item, member, mlen) == 0
                && (item[mlen] == '=' || item[mlen] == separator || item[mlen] == ';' || item[mlen] == '\0')) {
            result = 1;
            break;
        }
    }

    return result;
}

void
HttpHeader::removeConnectionHeaderEntries()
{
    if (httpHeaderHas(this, HDR_CONNECTION)) {
        /* anything that matches Connection list member will be deleted */
        String strConnection = httpHeaderGetList(this, HDR_CONNECTION);
        const HttpHeaderEntry *e;
        HttpHeaderPos pos = HttpHeaderInitPos;
        /*
         * think: on-average-best nesting of the two loops (hdrEntry
         * and strListItem) @?@
         */
        /*
         * maybe we should delete standard stuff ("keep-alive","close")
         * from strConnection first?
         */

        while ((e = httpHeaderGetEntry(this, &pos))) {
            if (strListIsMember(&strConnection, e->name.buf(), ','))
                httpHeaderDelAt(this, pos);
        }

        httpHeaderDelById(this, HDR_CONNECTION);
        strConnection.clean();
    }
}