[thirdparty/cups.git] / doc / help / api-array.html

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" "http://www.w3.org/TR/REC-html40/loose.dtd">
<html>
<!-- SECTION: Programming -->
<head>
<title>Array API</title>
<meta name="keywords" content="Programming">
<meta name="creator" content="Mini-XML v2.5">
<style type="text/css"><!--
BODY {
  font-family: lucida grande, geneva, helvetica, arial, sans-serif;
}

H1, H2, H3, H4, H5, H6, P, TD, TH {
  font-family: lucida grande, geneva, helvetica, arial, sans-serif;
}

KBD {
  font-family: monaco, courier, monospace;
  font-weight: bold;
}

PRE {
  font-family: monaco, courier, monospace;
}

PRE.command {
  margin-left: 36pt;
}

PRE.example {
  background: #eeeeee;
  border: dotted thin #999999;
  margin-left: 36pt;
  padding: 10px;
}

PRE.command EM, PRE.example EM {
  font-family: lucida grande, geneva, helvetica, arial, sans-serif;
}

P.command {
  font-family: monaco, courier, monospace;
  margin-left: 36pt;
}

P.formula {
  font-style: italic;
  margin-left: 36pt;
}

BLOCKQUOTE {
  background: #cccccc;
  border: solid thin #999999;
  padding: 10pt;
}

A:link, A:visited {
  font-weight: normal;
  text-decoration: none;
}

A:link:hover, A:visited:hover, A:active {
  text-decoration: underline;
}

SUB, SUP {
  font-size: 50%;
}

DIV.table TABLE {
  border: solid thin #999999;
  border-collapse: collapse;
  border-spacing: 0;
  margin-left: auto;
  margin-right: auto;
}

DIV.table CAPTION {
  caption-side: top;
  font-size: 120%;
  font-style: italic;
  font-weight: bold;
  margin-left: auto;
  margin-right: auto;
}

DIV.table TABLE TD {
  border: solid thin #cccccc;
  padding-top: 5pt;
}

DIV.table TABLE TH {
  background: #cccccc;
  border: none;
  border-bottom: solid thin #999999;
}

DIV.figure TABLE {
  margin-left: auto;
  margin-right: auto;
}

DIV.figure CAPTION {
  caption-side: bottom;
  font-size: 120%;
  font-style: italic;
  font-weight: bold;
  margin-left: auto;
  margin-right: auto;
}

TH.label {
  padding-top: 5pt;
  text-align: right;
  vertical-align: top;
}

HR {
  border: solid thin;
}

SPAN.info {
  background: #000000;
  border: thin solid #000000;
  color: #ffffff;
  font-size: 80%;
  font-style: italic;
  font-weight: bold;
  white-space: nowrap;
}

H2 SPAN.info, H3 SPAN.info, H4 SPAN.info {
  float: right;
  font-size: 100%;
}

H2.title, H3.title {
  border-bottom: solid 2pt #000000;
}

DT {
  margin-left: 36pt;
  margin-top: 12pt;
}

DD {
  margin-left: 54pt;
}

DL.category DT {
  font-weight: bold;
}

P.summary {
  margin-left: 36pt;
  font-family: monaco, courier, monospace;
}

SPAN.message {
  font-style: italic;
  font-size: smaller;
}

DIV.summary TABLE {
  border: solid thin #999999;
  border-collapse: collapse;
  border-spacing: 0;
  margin: 10px;
}

DIV.summary TABLE TD, DIV.summary TABLE TH {
  border: solid thin #999999;
  padding: 5px;
  text-align: left;
  vertical-align: top;
}

DIV.summary TABLE THEAD TH {
  background: #eeeeee;
}

/* API documentation styles... */
div.body h1 {
  margin: 0;
}
div.body h2 {
  margin-top: 1.5em;
}
div.body h3, div.body h4, div.body h5 {
  margin-bottom: 0.5em;
  margin-top: 1.5em;
}
.class, .enumeration, .function, .struct, .typedef, .union {
  border-bottom: solid thin #999999;
  margin-bottom: 0;
  margin-top: 2em;
}
.description {
  margin-top: 0.5em;
}
code, p.code, pre, ul.code li {
  font-family: monaco, courier, monospace;
  font-size: 90%;
}
ul.code, ul.contents, ul.subcontents {
  list-style-type: none;
  margin: 0;
  padding-left: 0;
}
ul.code li {
  margin: 0;
}
ul.contents > li {
  margin-top: 1em;
}
ul.contents li ul.code, ul.contents li ul.subcontents {
  padding-left: 2em;
}
div.body dl {
  margin-left: 0;
  margin-top: 0;
}
div.body dt {
  font-style: italic;
  margin-left: 0;
  margin-top: 0;
}
div.body dd {
  margin-bottom: 0.5em;
}

/* This is just for the HTML files generated with the framedhelp target */
div.contents {
  background: #e8e8e8;
  border: solid thin black;
  padding: 10px;
}
div.contents h1 {
  font-size: 110%;
}
div.contents h2 {
  font-size: 100%;
}
div.contents ul.contents {
  font-size: 80%;
}
div.contents ul.subcontents li {
  margin-left: 1em;
  text-indent: -1em;
}
--></style>
</head>
<body>
<div class='body'>
<!--
  "$Id: api-array.header 7266 2008-01-29 02:15:29Z mike $"

  Array API header for the Common UNIX Printing System (CUPS).

  Copyright 2008 by Apple Inc.

  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/".
-->

<h1 class="title">Array API</h1>

<div class='summary'><table summary='General Information'>
<thead>
<tr>
	<th>Header</th>
	<th>cups/array.h</th>
</tr>
</thead>
<tbody>
<tr>
	<th>Library</th>
	<td>-lcups</td>
</tr>
<tr>
	<th>See Also</th>
	<td>Programming: <a href='api-overview.html' target='_top'>Introduction to CUPS Programming</a></td>
</tr>
</tbody>
</table></div>
<h2 class="title">Contents</h2>
<ul class="contents">
</li>
<li><a href="#OVERVIEW">Overview</a><ul class="subcontents">
<li><a href="#MANAGING_ARRAYS">Managing Arrays</a></li>
<li><a href="#FINDING_AND_ENUMERATING">Finding and Enumerating Elements</a></li>
</ul></li>
<li><a href="#FUNCTIONS">Functions</a><ul class="code">
<li><a href="#cupsArrayAdd" title="Add an element to the array.">cupsArrayAdd</a></li>
<li><a href="#cupsArrayClear" title="Clear the array.">cupsArrayClear</a></li>
<li><a href="#cupsArrayCount" title="Get the number of elements in the array.">cupsArrayCount</a></li>
<li><a href="#cupsArrayCurrent" title="Return the current element in the array.">cupsArrayCurrent</a></li>
<li><a href="#cupsArrayDelete" title="Free all memory used by the array.">cupsArrayDelete</a></li>
<li><a href="#cupsArrayDup" title="Duplicate the array.">cupsArrayDup</a></li>
<li><a href="#cupsArrayFind" title="Find an element in the array.">cupsArrayFind</a></li>
<li><a href="#cupsArrayFirst" title="Get the first element in the array.">cupsArrayFirst</a></li>
<li><a href="#cupsArrayGetIndex" title="Get the index of the current element.">cupsArrayGetIndex</a></li>
<li><a href="#cupsArrayGetInsert" title="Get the index of the last inserted element.">cupsArrayGetInsert</a></li>
<li><a href="#cupsArrayIndex" title="Get the N-th element in the array.">cupsArrayIndex</a></li>
<li><a href="#cupsArrayInsert" title="Insert an element in the array.">cupsArrayInsert</a></li>
<li><a href="#cupsArrayLast" title="Get the last element in the array.">cupsArrayLast</a></li>
<li><a href="#cupsArrayNew" title="Create a new array.">cupsArrayNew</a></li>
<li><a href="#cupsArrayNew2" title="Create a new array with hash.">cupsArrayNew2</a></li>
<li><a href="#cupsArrayNext" title="Get the next element in the array.">cupsArrayNext</a></li>
<li><a href="#cupsArrayPrev" title="Get the previous element in the array.">cupsArrayPrev</a></li>
<li><a href="#cupsArrayRemove" title="Remove an element from the array.">cupsArrayRemove</a></li>
<li><a href="#cupsArrayRestore" title="Reset the current element to the last cupsArraySave.">cupsArrayRestore</a></li>
<li><a href="#cupsArraySave" title="Mark the current element for a later cupsArrayRestore.">cupsArraySave</a></li>
<li><a href="#cupsArrayUserData" title="Return the user data for an array.">cupsArrayUserData</a></li>
</ul>
<li><a href="#TYPES">Data Types</a><ul class="code">
	<li><a href="#cups_ahash_func_t" title="Array hash function">cups_ahash_func_t</a></li>
	<li><a href="#cups_array_func_t" title="Array comparison function">cups_array_func_t</a></li>
	<li><a href="#cups_array_t" title="CUPS array type">cups_array_t</a></li>
</ul></li>
</ul>
<!--
  "$Id: api-array.shtml 7266 2008-01-29 02:15:29Z mike $"

  Array API introduction for the Common UNIX Printing System (CUPS).

  Copyright 2007-2008 by Apple Inc.
  Copyright 1997-2006 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/".
-->

<h2 class='title'><a name='OVERVIEW'>Overview</a></h2>

<p>The CUPS array API provides a high-performance generic array container.
The contents of the array container can be sorted and the container itself is
designed for optimal speed and memory usage under a wide variety of conditions.
Sorted arrays use a binary search algorithm from the last found or inserted
element to quickly find matching elements in the array. Arrays created with the
optional hash function can often find elements with a single lookup. The
<a href='#cups_array_t'><code>cups_array_t</code></a> type is used when
referring to a CUPS array.</p>

<p>The CUPS scheduler (<tt>cupsd</tt>) and many of the CUPS API
functions use the array API to efficiently manage large lists of
data.</p>

<h3><a name='MANAGING_ARRAYS'>Managing Arrays</a></h3>

<p>Arrays are created using either the
<a href='#cupsArrayNew'><code>cupsArrayNew</code></a> or
<a href='#cupsArrayNew2'><code>cupsArrayNew2</code></a> functions. The
first function creates a new array with the specified callback function
and user data pointer:</p>

<pre class='example'>
#include &lt;cups/array.h&gt;

static int compare_func(void *first, void *second, void *user_data);

void *user_data;
<a href='#cups_array_t'>cups_array_t</a> *array = <a href='#cupsArrayNew'>cupsArrayNew</a>(compare_func, user_data);
</pre>

<p>The comparison function (type
<a href="#cups_arrayfunc_t"><code>cups_arrayfunc_t</code></a>) is called
whenever an element is added to the array and can be <code>NULL</code> to
create an unsorted array. The function returns -1 if the first element should
come before the second, 0 if the first and second elements should have the same
ordering, and 1 if the first element should come after the second.</p>

<p>The "user_data" pointer is passed to your comparison function. Pass
<code>NULL</code> if you do not need to associate the elements in your array
with additional information.</p>

<p>The <a href='#cupsArrayNew2'><code>cupsArrayNew2</code></a> function adds
two more arguments to support hashed lookups, which can potentially provide
instantaneous ("O(1)") lookups in your array:</p>

<pre class='example'>
#include &lt;cups/array.h&gt;

#define HASH_SIZE 512 /* Size of hash table */

static int compare_func(void *first, void *second, void *user_data);
static int hash_func(void *element, void *user_data);

void *user_data;
<a href='#cups_array_t'>cups_array_t</a> *array = <a href='#cupsArrayNew2'>cupsArrayNew2</a>(compare_func, user_data, hash_func, HASH_SIZE);
</pre>

<p>The hash function (type
<a href="#cups_ahash_func_t"><code>cups_ahash_func_t</code></a>) returns a
number from 0 to (hash_size-1) that (hopefully) uniquely identifies the
element and is called whenever you look up an element in the array with
<a href='#cupsArrayFind'><code>cupsArrayFind</code></a>. The hash size is
only limited by available memory, but generally should not be larger than
16384 to realize any performance improvement.</p>

<p>Once you have created the array, you add elements using the
<a href='#cupsArrayAdd'><code>cupsArrayAdd</code></a>
<a href='#cupsArrayInsert'><code>cupsArrayInsert</code></a> functions.
The first function adds an element to the array, adding the new element
after any elements that have the same order, while the second inserts the
element before others with the same order. For unsorted arrays,
<a href='#cupsArrayAdd'><code>cupsArrayAdd</code></a> appends the elemnt to
the end of the array while
<a href='#cupsArrayInsert'><code>cupsArrayInsert</code></a> inserts the
element at the beginning of the array. For example, the following code
creates a sorted array of character strings:</p>

<pre class='example'>
#include &lt;cups/array.h&gt;

/* Use strcmp() to compare strings - it will ignore the user_data pointer */
<a href='#cups_array_t'>cups_array_t</a> *array = <a href='#cupsArrayNew'>cupsArrayNew</a>((<a href='#cups_array_func_t'>cups_array_func_t</a>)strcmp, NULL);

/* Add four strings to the array */
<a href='#cupsArrayAdd'>cupsArrayAdd</a>(array, "One Fish");
<a href='#cupsArrayAdd'>cupsArrayAdd</a>(array, "Two Fish");
<a href='#cupsArrayAdd'>cupsArrayAdd</a>(array, "Red Fish");
<a href='#cupsArrayAdd'>cupsArrayAdd</a>(array, "Blue Fish");
</pre>

<p>Elements are removed using the
<a href='#cupsArrayRemove'><code>cupsArrayRemove</code></a> function, for
example:</p>

<pre class='example'>
#include &lt;cups/array.h&gt;

/* Use strcmp() to compare strings - it will ignore the user_data pointer */
<a href='#cups_array_t'>cups_array_t</a> *array = <a href='#cupsArrayNew'>cupsArrayNew</a>((<a href='#cups_array_func_t'>cups_array_func_t</a>)strcmp, NULL);

/* Add four strings to the array */
<a href='#cupsArrayAdd'>cupsArrayAdd</a>(array, "One Fish");
<a href='#cupsArrayAdd'>cupsArrayAdd</a>(array, "Two Fish");
<a href='#cupsArrayAdd'>cupsArrayAdd</a>(array, "Red Fish");
<a href='#cupsArrayAdd'>cupsArrayAdd</a>(array, "Blue Fish");

/* Remove "Red Fish" */
<a href='#cupsArrayRemove'>cupsArrayRemove</a>(array, "Red Fish");
</pre>

<p>Finally, you free the memory used by the array using the
<a href='#cupsArrayDelete'><code>cupsArrayDelete</code></a> function. All
of the memory for the array and hash table (if any) is freed, however <em>CUPS
does not free the elements</em> - if necessary, you must allocate and free the
elements yourself.</p>

<h3><a name='FINDING_AND_ENUMERATING'>Finding and Enumerating Elements</a></h3>

<p>CUPS provides several functions to find and enumerate elements in an
array. Each one sets or updates a "current index" into the array, such that
future lookups will start where the last one left off:</p>

<dl>
	<dt><a href='#cupsArrayFind'><code>cupsArrayFind</code></a></dt>
	<dd>Returns the first matching element .</dd>
	<dt><a href='#cupsArrayFirst'><code>cupsArrayFirst</code></a></dt>
	<dd>Returns the first element in the array.</dd>
	<dt><a href='#cupsArrayIndex'><code>cupsArrayIndex</code></a></dt>
	<dd>Returns the Nth element in the array.</dd>
	<dt><a href='#cupsArrayLast'><code>cupsArrayLast</code></a></dt>
	<dd>Returns the last element in the array.</dd>
	<dt><a href='#cupsArrayNext'><code>cupsArrayNext</code></a></dt>
	<dd>Returns the next element in the array.</dd>
	<dt><a href='#cupsArrayPrev'><code>cupsArrayPrev</code></a></dt>
	<dd>Returns the previous element in the array.</dd>
</dl>

<p>Each of these functions returns <code>NULL</code> when there is no
corresponding element.  For example, a simple <code>for</code> loop using the
<a href='#cupsArrayFirst'><code>cupsArrayFirst</code></a> and
<a href='#cupsArrayNext'><code>cupsArrayNext</code></a> functions will
enumerate all of the strings in our previous example:</p> 

<pre class='example'>
#include &lt;cups/array.h&gt;

/* Use strcmp() to compare strings - it will ignore the user_data pointer */
<a href='#cups_array_t'>cups_array_t</a> *array = <a href='#cupsArrayNew'>cupsArrayNew</a>((<a href='#cups_array_func_t'>cups_array_func_t</a>)strcmp, NULL);

/* Add four strings to the array */
<a href='#cupsArrayAdd'>cupsArrayAdd</a>(array, "One Fish");
<a href='#cupsArrayAdd'>cupsArrayAdd</a>(array, "Two Fish");
<a href='#cupsArrayAdd'>cupsArrayAdd</a>(array, "Red Fish");
<a href='#cupsArrayAdd'>cupsArrayAdd</a>(array, "Blue Fish");

/* Show all of the strings in the array */
char *s;
for (s = (char *)<a href='#cupsArrayFirst'>cupsArrayFirst</a>(array); s != NULL; s = (char *)<a href='#cupsArrayNext'>cupsArrayNext</a>(array))
  puts(s);
</pre>
<h2 class="title"><a name="FUNCTIONS">Functions</a></h2>
<h3 class="function"><span class="info">&nbsp;CUPS 1.2&nbsp;</span><a name="cupsArrayAdd">cupsArrayAdd</a></h3>
<p class="description">Add an element to the array.</p>
<p class="code">
int cupsArrayAdd (<br>
&nbsp;&nbsp;&nbsp;&nbsp;<a href="#cups_array_t">cups_array_t</a> *a,<br>
&nbsp;&nbsp;&nbsp;&nbsp;void *e<br>
);</p>
<h4 class="parameters">Parameters</h4>
<dl>
<dt>a</dt>
<dd class="description">Array</dd>
<dt>e</dt>
<dd class="description">Element</dd>
</dl>
<h4 class="returnvalue">Return Value</h4>
<p class="description">1 on success, 0 on failure</p>
<h4 class="discussion">Discussion</h4>
<p class="discussion">When adding an element to a sorted array, non-unique elements are
appended at the end of the run.  For unsorted arrays, the element
is inserted at the end of the array.

</p>
<h3 class="function"><span class="info">&nbsp;CUPS 1.2&nbsp;</span><a name="cupsArrayClear">cupsArrayClear</a></h3>
<p class="description">Clear the array.</p>
<p class="code">
void cupsArrayClear (<br>
&nbsp;&nbsp;&nbsp;&nbsp;<a href="#cups_array_t">cups_array_t</a> *a<br>
);</p>
<h4 class="parameters">Parameters</h4>
<dl>
<dt>a</dt>
<dd class="description">Array</dd>
</dl>
<h3 class="function"><span class="info">&nbsp;CUPS 1.2&nbsp;</span><a name="cupsArrayCount">cupsArrayCount</a></h3>
<p class="description">Get the number of elements in the array.</p>
<p class="code">
int cupsArrayCount (<br>
&nbsp;&nbsp;&nbsp;&nbsp;<a href="#cups_array_t">cups_array_t</a> *a<br>
);</p>
<h4 class="parameters">Parameters</h4>
<dl>
<dt>a</dt>
<dd class="description">Array</dd>
</dl>
<h4 class="returnvalue">Return Value</h4>
<p class="description">Number of elements</p>
<h3 class="function"><span class="info">&nbsp;CUPS 1.2&nbsp;</span><a name="cupsArrayCurrent">cupsArrayCurrent</a></h3>
<p class="description">Return the current element in the array.</p>
<p class="code">
void *cupsArrayCurrent (<br>
&nbsp;&nbsp;&nbsp;&nbsp;<a href="#cups_array_t">cups_array_t</a> *a<br>
);</p>
<h4 class="parameters">Parameters</h4>
<dl>
<dt>a</dt>
<dd class="description">Array</dd>
</dl>
<h4 class="returnvalue">Return Value</h4>
<p class="description">Element</p>
<h3 class="function"><span class="info">&nbsp;CUPS 1.2&nbsp;</span><a name="cupsArrayDelete">cupsArrayDelete</a></h3>
<p class="description">Free all memory used by the array.</p>
<p class="code">
void cupsArrayDelete (<br>
&nbsp;&nbsp;&nbsp;&nbsp;<a href="#cups_array_t">cups_array_t</a> *a<br>
);</p>
<h4 class="parameters">Parameters</h4>
<dl>
<dt>a</dt>
<dd class="description">Array</dd>
</dl>
<h3 class="function"><span class="info">&nbsp;CUPS 1.2&nbsp;</span><a name="cupsArrayDup">cupsArrayDup</a></h3>
<p class="description">Duplicate the array.</p>
<p class="code">
<a href="#cups_array_t">cups_array_t</a> *cupsArrayDup (<br>
&nbsp;&nbsp;&nbsp;&nbsp;<a href="#cups_array_t">cups_array_t</a> *a<br>
);</p>
<h4 class="parameters">Parameters</h4>
<dl>
<dt>a</dt>
<dd class="description">Array</dd>
</dl>
<h4 class="returnvalue">Return Value</h4>
<p class="description">Duplicate array</p>
<h3 class="function"><span class="info">&nbsp;CUPS 1.2&nbsp;</span><a name="cupsArrayFind">cupsArrayFind</a></h3>
<p class="description">Find an element in the array.</p>
<p class="code">
void *cupsArrayFind (<br>
&nbsp;&nbsp;&nbsp;&nbsp;<a href="#cups_array_t">cups_array_t</a> *a,<br>
&nbsp;&nbsp;&nbsp;&nbsp;void *e<br>
);</p>
<h4 class="parameters">Parameters</h4>
<dl>
<dt>a</dt>
<dd class="description">Array</dd>
<dt>e</dt>
<dd class="description">Element</dd>
</dl>
<h4 class="returnvalue">Return Value</h4>
<p class="description">Element found or <code>NULL</code></p>
<h3 class="function"><span class="info">&nbsp;CUPS 1.2&nbsp;</span><a name="cupsArrayFirst">cupsArrayFirst</a></h3>
<p class="description">Get the first element in the array.</p>
<p class="code">
void *cupsArrayFirst (<br>
&nbsp;&nbsp;&nbsp;&nbsp;<a href="#cups_array_t">cups_array_t</a> *a<br>
);</p>
<h4 class="parameters">Parameters</h4>
<dl>
<dt>a</dt>
<dd class="description">Array</dd>
</dl>
<h4 class="returnvalue">Return Value</h4>
<p class="description">First element or <code>NULL</code></p>
<h3 class="function"><span class="info">&nbsp;CUPS 1.3&nbsp;</span><a name="cupsArrayGetIndex">cupsArrayGetIndex</a></h3>
<p class="description">Get the index of the current element.</p>
<p class="code">
int cupsArrayGetIndex (<br>
&nbsp;&nbsp;&nbsp;&nbsp;<a href="#cups_array_t">cups_array_t</a> *a<br>
);</p>
<h4 class="parameters">Parameters</h4>
<dl>
<dt>a</dt>
<dd class="description">Array</dd>
</dl>
<h4 class="returnvalue">Return Value</h4>
<p class="description">Index of the current element</p>
<h3 class="function"><span class="info">&nbsp;CUPS 1.3&nbsp;</span><a name="cupsArrayGetInsert">cupsArrayGetInsert</a></h3>
<p class="description">Get the index of the last inserted element.</p>
<p class="code">
int cupsArrayGetInsert (<br>
&nbsp;&nbsp;&nbsp;&nbsp;<a href="#cups_array_t">cups_array_t</a> *a<br>
);</p>
<h4 class="parameters">Parameters</h4>
<dl>
<dt>a</dt>
<dd class="description">Array</dd>
</dl>
<h4 class="returnvalue">Return Value</h4>
<p class="description">Index of the last inserted element</p>
<h3 class="function"><span class="info">&nbsp;CUPS 1.2&nbsp;</span><a name="cupsArrayIndex">cupsArrayIndex</a></h3>
<p class="description">Get the N-th element in the array.</p>
<p class="code">
void *cupsArrayIndex (<br>
&nbsp;&nbsp;&nbsp;&nbsp;<a href="#cups_array_t">cups_array_t</a> *a,<br>
&nbsp;&nbsp;&nbsp;&nbsp;int n<br>
);</p>
<h4 class="parameters">Parameters</h4>
<dl>
<dt>a</dt>
<dd class="description">Array</dd>
<dt>n</dt>
<dd class="description">Index into array, starting at 0</dd>
</dl>
<h4 class="returnvalue">Return Value</h4>
<p class="description">N-th element or <code>NULL</code></p>
<h3 class="function"><span class="info">&nbsp;CUPS 1.2&nbsp;</span><a name="cupsArrayInsert">cupsArrayInsert</a></h3>
<p class="description">Insert an element in the array.</p>
<p class="code">
int cupsArrayInsert (<br>
&nbsp;&nbsp;&nbsp;&nbsp;<a href="#cups_array_t">cups_array_t</a> *a,<br>
&nbsp;&nbsp;&nbsp;&nbsp;void *e<br>
);</p>
<h4 class="parameters">Parameters</h4>
<dl>
<dt>a</dt>
<dd class="description">Array</dd>
<dt>e</dt>
<dd class="description">Element</dd>
</dl>
<h4 class="returnvalue">Return Value</h4>
<p class="description">0 on failure, 1 on success</p>
<h4 class="discussion">Discussion</h4>
<p class="discussion">When inserting an element in a sorted array, non-unique elements are
inserted at the beginning of the run.  For unsorted arrays, the element
is inserted at the beginning of the array.

</p>
<h3 class="function"><span class="info">&nbsp;CUPS 1.2&nbsp;</span><a name="cupsArrayLast">cupsArrayLast</a></h3>
<p class="description">Get the last element in the array.</p>
<p class="code">
void *cupsArrayLast (<br>
&nbsp;&nbsp;&nbsp;&nbsp;<a href="#cups_array_t">cups_array_t</a> *a<br>
);</p>
<h4 class="parameters">Parameters</h4>
<dl>
<dt>a</dt>
<dd class="description">Array</dd>
</dl>
<h4 class="returnvalue">Return Value</h4>
<p class="description">Last element or <code>NULL</code></p>
<h3 class="function"><span class="info">&nbsp;CUPS 1.2&nbsp;</span><a name="cupsArrayNew">cupsArrayNew</a></h3>
<p class="description">Create a new array.</p>
<p class="code">
<a href="#cups_array_t">cups_array_t</a> *cupsArrayNew (<br>
&nbsp;&nbsp;&nbsp;&nbsp;<a href="#cups_array_func_t">cups_array_func_t</a> f,<br>
&nbsp;&nbsp;&nbsp;&nbsp;void *d<br>
);</p>
<h4 class="parameters">Parameters</h4>
<dl>
<dt>f</dt>
<dd class="description">Comparison function</dd>
<dt>d</dt>
<dd class="description">User data</dd>
</dl>
<h4 class="returnvalue">Return Value</h4>
<p class="description">Array</p>
<h3 class="function"><span class="info">&nbsp;CUPS 1.3&nbsp;</span><a name="cupsArrayNew2">cupsArrayNew2</a></h3>
<p class="description">Create a new array with hash.</p>
<p class="code">
<a href="#cups_array_t">cups_array_t</a> *cupsArrayNew2 (<br>
&nbsp;&nbsp;&nbsp;&nbsp;<a href="#cups_array_func_t">cups_array_func_t</a> f,<br>
&nbsp;&nbsp;&nbsp;&nbsp;void *d,<br>
&nbsp;&nbsp;&nbsp;&nbsp;<a href="#cups_ahash_func_t">cups_ahash_func_t</a> h,<br>
&nbsp;&nbsp;&nbsp;&nbsp;int hsize<br>
);</p>
<h4 class="parameters">Parameters</h4>
<dl>
<dt>f</dt>
<dd class="description">Comparison function</dd>
<dt>d</dt>
<dd class="description">User data</dd>
<dt>h</dt>
<dd class="description">Hash function</dd>
<dt>hsize</dt>
<dd class="description">Hash size</dd>
</dl>
<h4 class="returnvalue">Return Value</h4>
<p class="description">Array</p>
<h3 class="function"><span class="info">&nbsp;CUPS 1.2&nbsp;</span><a name="cupsArrayNext">cupsArrayNext</a></h3>
<p class="description">Get the next element in the array.</p>
<p class="code">
void *cupsArrayNext (<br>
&nbsp;&nbsp;&nbsp;&nbsp;<a href="#cups_array_t">cups_array_t</a> *a<br>
);</p>
<h4 class="parameters">Parameters</h4>
<dl>
<dt>a</dt>
<dd class="description">Array</dd>
</dl>
<h4 class="returnvalue">Return Value</h4>
<p class="description">Next element or <code>NULL</code></p>
<h3 class="function"><span class="info">&nbsp;CUPS 1.2&nbsp;</span><a name="cupsArrayPrev">cupsArrayPrev</a></h3>
<p class="description">Get the previous element in the array.</p>
<p class="code">
void *cupsArrayPrev (<br>
&nbsp;&nbsp;&nbsp;&nbsp;<a href="#cups_array_t">cups_array_t</a> *a<br>
);</p>
<h4 class="parameters">Parameters</h4>
<dl>
<dt>a</dt>
<dd class="description">Array</dd>
</dl>
<h4 class="returnvalue">Return Value</h4>
<p class="description">Previous element or <code>NULL</code></p>
<h3 class="function"><span class="info">&nbsp;CUPS 1.2&nbsp;</span><a name="cupsArrayRemove">cupsArrayRemove</a></h3>
<p class="description">Remove an element from the array.</p>
<p class="code">
int cupsArrayRemove (<br>
&nbsp;&nbsp;&nbsp;&nbsp;<a href="#cups_array_t">cups_array_t</a> *a,<br>
&nbsp;&nbsp;&nbsp;&nbsp;void *e<br>
);</p>
<h4 class="parameters">Parameters</h4>
<dl>
<dt>a</dt>
<dd class="description">Array</dd>
<dt>e</dt>
<dd class="description">Element</dd>
</dl>
<h4 class="returnvalue">Return Value</h4>
<p class="description">1 on success, 0 on failure</p>
<h3 class="function"><span class="info">&nbsp;CUPS 1.2&nbsp;</span><a name="cupsArrayRestore">cupsArrayRestore</a></h3>
<p class="description">Reset the current element to the last cupsArraySave.</p>
<p class="code">
void *cupsArrayRestore (<br>
&nbsp;&nbsp;&nbsp;&nbsp;<a href="#cups_array_t">cups_array_t</a> *a<br>
);</p>
<h4 class="parameters">Parameters</h4>
<dl>
<dt>a</dt>
<dd class="description">Array</dd>
</dl>
<h4 class="returnvalue">Return Value</h4>
<p class="description">New current element</p>
<h3 class="function"><span class="info">&nbsp;CUPS 1.2&nbsp;</span><a name="cupsArraySave">cupsArraySave</a></h3>
<p class="description">Mark the current element for a later cupsArrayRestore.</p>
<p class="code">
int cupsArraySave (<br>
&nbsp;&nbsp;&nbsp;&nbsp;<a href="#cups_array_t">cups_array_t</a> *a<br>
);</p>
<h4 class="parameters">Parameters</h4>
<dl>
<dt>a</dt>
<dd class="description">Array</dd>
</dl>
<h4 class="returnvalue">Return Value</h4>
<p class="description">1 on success, 0 on failure</p>
<h4 class="discussion">Discussion</h4>
<p class="discussion">The save/restore stack is guaranteed to be at least 32 elements deep.

</p>
<h3 class="function"><span class="info">&nbsp;CUPS 1.2&nbsp;</span><a name="cupsArrayUserData">cupsArrayUserData</a></h3>
<p class="description">Return the user data for an array.</p>
<p class="code">
void *cupsArrayUserData (<br>
&nbsp;&nbsp;&nbsp;&nbsp;<a href="#cups_array_t">cups_array_t</a> *a<br>
);</p>
<h4 class="parameters">Parameters</h4>
<dl>
<dt>a</dt>
<dd class="description">Array</dd>
</dl>
<h4 class="returnvalue">Return Value</h4>
<p class="description">User data</p>
<h2 class="title"><a name="TYPES">Data Types</a></h2>
<h3 class="typedef"><a name="cups_ahash_func_t">cups_ahash_func_t</a></h3>
<p class="description">Array hash function</p>
<p class="code">
typedef int (*cups_ahash_func_t)(void *element, void *data);
</p>
<h3 class="typedef"><a name="cups_array_func_t">cups_array_func_t</a></h3>
<p class="description">Array comparison function</p>
<p class="code">
typedef int (*cups_array_func_t)(void *first, void *second, void *data);
</p>
<h3 class="typedef"><a name="cups_array_t">cups_array_t</a></h3>
<p class="description">CUPS array type</p>
<p class="code">
typedef struct _cups_array_s cups_array_t;
</p>
</div>
</body>
</html>