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  5. <head>
  6. <!-- Copyright 1999,2000 Clark Cooper <coopercc@netheaven.com>
  7.      All rights reserved.
  8.      This is free software. You may distribute or modify according to
  9.      the terms of the MIT/X License -->
  10.   <title>Expat XML Parser</title>
  11.   <meta name="author" content="Clark Cooper, coopercc@netheaven.com" />
  12.   <meta http-equiv="Content-Style-Type" content="text/css" />
  13.   <link href="style.css" rel="stylesheet" type="text/css" />
  14. </head>
  15. <body>
  16.   <table cellspacing="0" cellpadding="0" width="100%">
  17.     <tr>
  18.       <td class="corner"><img src="expat.png" alt="(Expat logo)" /></td>
  19.       <td class="banner"><h1>The Expat XML Parser</h1></td>
  20.     </tr>
  21.     <tr>
  22.       <td class="releaseno">Release 2.0.1</td>
  23.       <td></td>
  24.     </tr>
  25.   </table>
  26. <div class="content">
  27.  
  28. <p>Expat is a library, written in C, for parsing XML documents. It's
  29. the underlying XML parser for the open source Mozilla project, Perl's
  30. <code>XML::Parser</code>, Python's <code>xml.parsers.expat</code>, and
  31. other open-source XML parsers.</p>
  32.  
  33. <p>This library is the creation of James Clark, who's also given us
  34. groff (an nroff look-alike), Jade (an implemention of ISO's DSSSL
  35. stylesheet language for SGML), XP (a Java XML parser package), XT (a
  36. Java XSL engine).  James was also the technical lead on the XML
  37. Working Group at W3C that produced the XML specification.</p>
  38.  
  39. <p>This is free software, licensed under the <a
  40. href="../COPYING">MIT/X Consortium license</a>. You may download it
  41. from <a href="http://www.libexpat.org/">the Expat home page</a>.
  42. </p>
  43.  
  44. <p>The bulk of this document was originally commissioned as an article
  45. by <a href="http://www.xml.com/">XML.com</a>. They graciously allowed
  46. Clark Cooper to retain copyright and to distribute it with Expat.
  47. This version has been substantially extended to include documentation
  48. on features which have been added since the original article was
  49. published, and additional information on using the original
  50. interface.</p>
  51.  
  52. <hr />
  53. <h2>Table of Contents</h2>
  54. <ul>
  55.  <li><a href="#overview">Overview</a></li>
  56.  <li><a href="#building">Building and Installing</a></li>
  57.  <li><a href="#using">Using Expat</a></li>
  58.  <li><a href="#reference">Reference</a>
  59.  <ul>
  60.    <li><a href="#creation">Parser Creation Functions</a>
  61.    <ul>
  62.      <li><a href="#XML_ParserCreate">XML_ParserCreate</a></li>
  63.      <li><a href="#XML_ParserCreateNS">XML_ParserCreateNS</a></li>
  64.      <li><a href="#XML_ParserCreate_MM">XML_ParserCreate_MM</a></li>
  65.      <li><a href="#XML_ExternalEntityParserCreate">XML_ExternalEntityParserCreate</a></li>
  66.      <li><a href="#XML_ParserFree">XML_ParserFree</a></li>
  67.      <li><a href="#XML_ParserReset">XML_ParserReset</a></li>
  68.    </ul>
  69.    </li>
  70.    <li><a href="#parsing">Parsing Functions</a>
  71.    <ul>
  72.      <li><a href="#XML_Parse">XML_Parse</a></li>
  73.      <li><a href="#XML_ParseBuffer">XML_ParseBuffer</a></li>
  74.      <li><a href="#XML_GetBuffer">XML_GetBuffer</a></li>
  75.      <li><a href="#XML_StopParser">XML_StopParser</a></li>
  76.      <li><a href="#XML_ResumeParser">XML_ResumeParser</a></li>
  77.      <li><a href="#XML_GetParsingStatus">XML_GetParsingStatus</a></li>
  78.    </ul>
  79.    </li>
  80.    <li><a href="#setting">Handler Setting Functions</a>
  81.    <ul>
  82.      <li><a href="#XML_SetStartElementHandler">XML_SetStartElementHandler</a></li>
  83.      <li><a href="#XML_SetEndElementHandler">XML_SetEndElementHandler</a></li>
  84.      <li><a href="#XML_SetElementHandler">XML_SetElementHandler</a></li>
  85.      <li><a href="#XML_SetCharacterDataHandler">XML_SetCharacterDataHandler</a></li>
  86.      <li><a href="#XML_SetProcessingInstructionHandler">XML_SetProcessingInstructionHandler</a></li>
  87.      <li><a href="#XML_SetCommentHandler">XML_SetCommentHandler</a></li>
  88.      <li><a href="#XML_SetStartCdataSectionHandler">XML_SetStartCdataSectionHandler</a></li>
  89.      <li><a href="#XML_SetEndCdataSectionHandler">XML_SetEndCdataSectionHandler</a></li>
  90.      <li><a href="#XML_SetCdataSectionHandler">XML_SetCdataSectionHandler</a></li>
  91.      <li><a href="#XML_SetDefaultHandler">XML_SetDefaultHandler</a></li>
  92.      <li><a href="#XML_SetDefaultHandlerExpand">XML_SetDefaultHandlerExpand</a></li>
  93.      <li><a href="#XML_SetExternalEntityRefHandler">XML_SetExternalEntityRefHandler</a></li>
  94.      <li><a href="#XML_SetExternalEntityRefHandlerArg">XML_SetExternalEntityRefHandlerArg</a></li>
  95.      <li><a href="#XML_SetSkippedEntityHandler">XML_SetSkippedEntityHandler</a></li>
  96.      <li><a href="#XML_SetUnknownEncodingHandler">XML_SetUnknownEncodingHandler</a></li>
  97.      <li><a href="#XML_SetStartNamespaceDeclHandler">XML_SetStartNamespaceDeclHandler</a></li>
  98.      <li><a href="#XML_SetEndNamespaceDeclHandler">XML_SetEndNamespaceDeclHandler</a></li>
  99.      <li><a href="#XML_SetNamespaceDeclHandler">XML_SetNamespaceDeclHandler</a></li>
  100.       <li><a href="#XML_SetXmlDeclHandler">XML_SetXmlDeclHandler</a></li>                
  101.      <li><a href="#XML_SetStartDoctypeDeclHandler">XML_SetStartDoctypeDeclHandler</a></li>
  102.      <li><a href="#XML_SetEndDoctypeDeclHandler">XML_SetEndDoctypeDeclHandler</a></li>
  103.      <li><a href="#XML_SetDoctypeDeclHandler">XML_SetDoctypeDeclHandler</a></li>
  104.      <li><a href="#XML_SetElementDeclHandler">XML_SetElementDeclHandler</a></li>
  105.      <li><a href="#XML_SetAttlistDeclHandler">XML_SetAttlistDeclHandler</a></li>
  106.      <li><a href="#XML_SetEntityDeclHandler">XML_SetEntityDeclHandler</a></li>
  107.      <li><a href="#XML_SetUnparsedEntityDeclHandler">XML_SetUnparsedEntityDeclHandler</a></li>
  108.      <li><a href="#XML_SetNotationDeclHandler">XML_SetNotationDeclHandler</a></li>
  109.      <li><a href="#XML_SetNotStandaloneHandler">XML_SetNotStandaloneHandler</a></li>
  110.    </ul>
  111.    </li>
  112.    <li><a href="#position">Parse Position and Error Reporting Functions</a>
  113.    <ul>
  114.      <li><a href="#XML_GetErrorCode">XML_GetErrorCode</a></li>
  115.      <li><a href="#XML_ErrorString">XML_ErrorString</a></li>
  116.      <li><a href="#XML_GetCurrentByteIndex">XML_GetCurrentByteIndex</a></li>
  117.      <li><a href="#XML_GetCurrentLineNumber">XML_GetCurrentLineNumber</a></li>
  118.      <li><a href="#XML_GetCurrentColumnNumber">XML_GetCurrentColumnNumber</a></li>
  119.      <li><a href="#XML_GetCurrentByteCount">XML_GetCurrentByteCount</a></li>
  120.      <li><a href="#XML_GetInputContext">XML_GetInputContext</a></li>
  121.    </ul>
  122.    </li>
  123.    <li><a href="#miscellaneous">Miscellaneous Functions</a>
  124.    <ul>
  125.      <li><a href="#XML_SetUserData">XML_SetUserData</a></li>
  126.      <li><a href="#XML_GetUserData">XML_GetUserData</a></li>
  127.      <li><a href="#XML_UseParserAsHandlerArg">XML_UseParserAsHandlerArg</a></li>
  128.      <li><a href="#XML_SetBase">XML_SetBase</a></li>
  129.      <li><a href="#XML_GetBase">XML_GetBase</a></li>
  130.      <li><a href="#XML_GetSpecifiedAttributeCount">XML_GetSpecifiedAttributeCount</a></li>
  131.      <li><a href="#XML_GetIdAttributeIndex">XML_GetIdAttributeIndex</a></li>
  132.      <li><a href="#XML_GetAttributeInfo">XML_GetAttributeInfo</a></li>
  133.      <li><a href="#XML_SetEncoding">XML_SetEncoding</a></li>
  134.      <li><a href="#XML_SetParamEntityParsing">XML_SetParamEntityParsing</a></li>
  135.      <li><a href="#XML_SetHashSalt">XML_SetHashSalt</a></li>
  136.      <li><a href="#XML_UseForeignDTD">XML_UseForeignDTD</a></li>
  137.      <li><a href="#XML_SetReturnNSTriplet">XML_SetReturnNSTriplet</a></li>
  138.      <li><a href="#XML_DefaultCurrent">XML_DefaultCurrent</a></li>
  139.      <li><a href="#XML_ExpatVersion">XML_ExpatVersion</a></li>
  140.      <li><a href="#XML_ExpatVersionInfo">XML_ExpatVersionInfo</a></li>
  141.      <li><a href="#XML_GetFeatureList">XML_GetFeatureList</a></li>
  142.      <li><a href="#XML_FreeContentModel">XML_FreeContentModel</a></li>
  143.      <li><a href="#XML_MemMalloc">XML_MemMalloc</a></li>
  144.      <li><a href="#XML_MemRealloc">XML_MemRealloc</a></li>
  145.      <li><a href="#XML_MemFree">XML_MemFree</a></li>
  146.    </ul>
  147.    </li>
  148.  </ul>  
  149.  </li>
  150. </ul>
  151.  
  152. <hr />
  153. <h2><a name="overview">Overview</a></h2>
  154.  
  155. <p>Expat is a stream-oriented parser. You register callback (or
  156. handler) functions with the parser and then start feeding it the
  157. document.  As the parser recognizes parts of the document, it will
  158. call the appropriate handler for that part (if you've registered one.)
  159. The document is fed to the parser in pieces, so you can start parsing
  160. before you have all the document. This also allows you to parse really
  161. huge documents that won't fit into memory.</p>
  162.  
  163. <p>Expat can be intimidating due to the many kinds of handlers and
  164. options you can set. But you only need to learn four functions in
  165. order to do 90% of what you'll want to do with it:</p>
  166.  
  167. <dl>
  168.  
  169. <dt><code><a href= "#XML_ParserCreate"
  170.              >XML_ParserCreate</a></code></dt>
  171.   <dd>Create a new parser object.</dd>
  172.  
  173. <dt><code><a href= "#XML_SetElementHandler"
  174.              >XML_SetElementHandler</a></code></dt>
  175.   <dd>Set handlers for start and end tags.</dd>
  176.  
  177. <dt><code><a href= "#XML_SetCharacterDataHandler"
  178.              >XML_SetCharacterDataHandler</a></code></dt>
  179.   <dd>Set handler for text.</dd>
  180.  
  181. <dt><code><a href= "#XML_Parse"
  182.              >XML_Parse</a></code></dt>
  183.   <dd>Pass a buffer full of document to the parser</dd>
  184. </dl>
  185.  
  186. <p>These functions and others are described in the <a
  187. href="#reference">reference</a> part of this document. The reference
  188. section also describes in detail the parameters passed to the
  189. different types of handlers.</p>
  190.  
  191. <p>Let's look at a very simple example program that only uses 3 of the
  192. above functions (it doesn't need to set a character handler.) The
  193. program <a href="../examples/outline.c">outline.c</a> prints an
  194. element outline, indenting child elements to distinguish them from the
  195. parent element that contains them. The start handler does all the
  196. work.  It prints two indenting spaces for every level of ancestor
  197. elements, then it prints the element and attribute
  198. information. Finally it increments the global <code>Depth</code>
  199. variable.</p>
  200.  
  201. <pre class="eg">
  202. int Depth;
  203.  
  204. void XMLCALL
  205. start(void *data, const char *el, const char **attr) {
  206.   int i;
  207.  
  208.   for (i = 0; i &lt; Depth; i++)
  209.     printf("  ");
  210.  
  211.   printf("%s", el);
  212.  
  213.   for (i = 0; attr[i]; i += 2) {
  214.     printf(" %s='%s'", attr[i], attr[i + 1]);
  215.   }
  216.  
  217.   printf("\n");
  218.   Depth++;
  219. }  /* End of start handler */
  220. </pre>
  221.  
  222. <p>The end tag simply does the bookkeeping work of decrementing
  223. <code>Depth</code>.</p>
  224. <pre class="eg">
  225. void XMLCALL
  226. end(void *data, const char *el) {
  227.   Depth--;
  228. }  /* End of end handler */
  229. </pre>
  230.  
  231. <p>Note the <code>XMLCALL</code> annotation used for the callbacks.
  232. This is used to ensure that the Expat and the callbacks are using the
  233. same calling convention in case the compiler options used for Expat
  234. itself and the client code are different.  Expat tries not to care
  235. what the default calling convention is, though it may require that it
  236. be compiled with a default convention of "cdecl" on some platforms.
  237. For code which uses Expat, however, the calling convention is
  238. specified by the <code>XMLCALL</code> annotation on most platforms;
  239. callbacks should be defined using this annotation.</p>
  240.  
  241. <p>The <code>XMLCALL</code> annotation was added in Expat 1.95.7, but
  242. existing working Expat applications don't need to add it (since they
  243. are already using the "cdecl" calling convention, or they wouldn't be
  244. working).  The annotation is only needed if the default calling
  245. convention may be something other than "cdecl".  To use the annotation
  246. safely with older versions of Expat, you can conditionally define it
  247. <em>after</em> including Expat's header file:</p>
  248.  
  249. <pre class="eg">
  250. #include &lt;expat.h&gt;
  251.  
  252. #ifndef XMLCALL
  253. #if defined(_MSC_EXTENSIONS) &amp;&amp; !defined(__BEOS__) &amp;&amp; !defined(__CYGWIN__)
  254. #define XMLCALL __cdecl
  255. #elif defined(__GNUC__)
  256. #define XMLCALL __attribute__((cdecl))
  257. #else
  258. #define XMLCALL
  259. #endif
  260. #endif
  261. </pre>
  262.  
  263. <p>After creating the parser, the main program just has the job of
  264. shoveling the document to the parser so that it can do its work.</p>
  265.  
  266. <hr />
  267. <h2><a name="building">Building and Installing Expat</a></h2>
  268.  
  269. <p>The Expat distribution comes as a compressed (with GNU gzip) tar
  270. file.  You may download the latest version from <a href=
  271. "http://sourceforge.net/projects/expat/" >Source Forge</a>.  After
  272. unpacking this, cd into the directory. Then follow either the Win32
  273. directions or Unix directions below.</p>
  274.  
  275. <h3>Building under Win32</h3>
  276.  
  277. <p>If you're using the GNU compiler under cygwin, follow the Unix
  278. directions in the next section. Otherwise if you have Microsoft's
  279. Developer Studio installed, then from Windows Explorer double-click on
  280. "expat.dsp" in the lib directory and build and install in the usual
  281. manner.</p>
  282.  
  283. <p>Alternatively, you may download the Win32 binary package that
  284. contains the "expat.h" include file and a pre-built DLL.</p>
  285.  
  286. <h3>Building under Unix (or GNU)</h3>
  287.  
  288. <p>First you'll need to run the configure shell script in order to
  289. configure the Makefiles and headers for your system.</p>
  290.  
  291. <p>If you're happy with all the defaults that configure picks for you,
  292. and you have permission on your system to install into /usr/local, you
  293. can install Expat with this sequence of commands:</p>
  294.  
  295. <pre class="eg">
  296. ./configure
  297. make
  298. make install
  299. </pre>
  300.  
  301. <p>There are some options that you can provide to this script, but the
  302. only one we'll mention here is the <code>--prefix</code> option. You
  303. can find out all the options available by running configure with just
  304. the <code>--help</code> option.</p>
  305.  
  306. <p>By default, the configure script sets things up so that the library
  307. gets installed in <code>/usr/local/lib</code> and the associated
  308. header file in <code>/usr/local/include</code>.  But if you were to
  309. give the option, <code>--prefix=/home/me/mystuff</code>, then the
  310. library and header would get installed in
  311. <code>/home/me/mystuff/lib</code> and
  312. <code>/home/me/mystuff/include</code> respectively.</p>
  313.  
  314. <h3>Configuring Expat Using the Pre-Processor</h3>
  315.  
  316. <p>Expat's feature set can be configured using a small number of
  317. pre-processor definitions.  The definition of this symbols does not
  318. affect the set of entry points for Expat, only the behavior of the API
  319. and the definition of character types in the case of
  320. <code>XML_UNICODE_WCHAR_T</code>.  The symbols are:</p>
  321.  
  322. <dl class="cpp-symbols">
  323. <dt>XML_DTD</dt>
  324. <dd>Include support for using and reporting DTD-based content.  If
  325. this is defined, default attribute values from an external DTD subset
  326. are reported and attribute value normalization occurs based on the
  327. type of attributes defined in the external subset.  Without
  328. this, Expat has a smaller memory footprint and can be faster, but will
  329. not load external entities or process conditional sections.  This does
  330. not affect the set of functions available in the API.</dd>
  331.  
  332. <dt>XML_NS</dt>
  333. <dd>When defined, support for the <cite><a href=
  334. "http://www.w3.org/TR/REC-xml-names/" >Namespaces in XML</a></cite>
  335. specification is included.</dd>
  336.  
  337. <dt>XML_UNICODE</dt>
  338. <dd>When defined, character data reported to the application is
  339. encoded in UTF-16 using wide characters of the type
  340. <code>XML_Char</code>.  This is implied if
  341. <code>XML_UNICODE_WCHAR_T</code> is defined.</dd>
  342.  
  343. <dt>XML_UNICODE_WCHAR_T</dt>
  344. <dd>If defined, causes the <code>XML_Char</code> character type to be
  345. defined using the <code>wchar_t</code> type; otherwise, <code>unsigned
  346. short</code> is used.  Defining this implies
  347. <code>XML_UNICODE</code>.</dd>
  348.  
  349. <dt>XML_LARGE_SIZE</dt>
  350. <dd>If defined, causes the <code>XML_Size</code> and <code>XML_Index</code>
  351. integer types to be at least 64 bits in size. This is intended to support
  352. processing of very large input streams, where the return values of
  353. <code><a href="#XML_GetCurrentByteIndex" >XML_GetCurrentByteIndex</a></code>,
  354. <code><a href="#XML_GetCurrentLineNumber" >XML_GetCurrentLineNumber</a></code> and
  355. <code><a href="#XML_GetCurrentColumnNumber" >XML_GetCurrentColumnNumber</a></code>
  356. could overflow. It may not be supported by all compilers, and is turned
  357. off by default.</dd>
  358.  
  359. <dt>XML_CONTEXT_BYTES</dt>
  360. <dd>The number of input bytes of markup context which the parser will
  361. ensure are available for reporting via <code><a href=
  362. "#XML_GetInputContext" >XML_GetInputContext</a></code>.  This is
  363. normally set to 1024, and must be set to a positive interger.  If this
  364. is not defined, the input context will not be available and <code><a
  365. href= "#XML_GetInputContext" >XML_GetInputContext</a></code> will
  366. always report NULL.  Without this, Expat has a smaller memory
  367. footprint and can be faster.</dd>
  368.  
  369. <dt>XML_STATIC</dt>
  370. <dd>On Windows, this should be set if Expat is going to be linked
  371. statically with the code that calls it; this is required to get all
  372. the right MSVC magic annotations correct.  This is ignored on other
  373. platforms.</dd>
  374.  
  375. <dt>XML_ATTR_INFO</dt>
  376. <dd>If defined, makes the the additional function <code><a href=
  377. "#XML_GetAttributeInfo" >XML_GetAttributeInfo</a></code> available
  378. for reporting attribute byte offsets.</dd>
  379. </dl>
  380.  
  381. <hr />
  382. <h2><a name="using">Using Expat</a></h2>
  383.  
  384. <h3>Compiling and Linking Against Expat</h3>
  385.  
  386. <p>Unless you installed Expat in a location not expected by your
  387. compiler and linker, all you have to do to use Expat in your programs
  388. is to include the Expat header (<code>#include &lt;expat.h&gt;</code>)
  389. in your files that make calls to it and to tell the linker that it
  390. needs to link against the Expat library.  On Unix systems, this would
  391. usually be done with the <code>-lexpat</code> argument.  Otherwise,
  392. you'll need to tell the compiler where to look for the Expat header
  393. and the linker where to find the Expat library.  You may also need to
  394. take steps to tell the operating system where to find this library at
  395. run time.</p>
  396.  
  397. <p>On a Unix-based system, here's what a Makefile might look like when
  398. Expat is installed in a standard location:</p>
  399.  
  400. <pre class="eg">
  401. CC=cc
  402. LDFLAGS=
  403. LIBS= -lexpat
  404. xmlapp: xmlapp.o
  405.        $(CC) $(LDFLAGS) -o xmlapp xmlapp.o $(LIBS)
  406. </pre>
  407.  
  408. <p>If you installed Expat in, say, <code>/home/me/mystuff</code>, then
  409. the Makefile would look like this:</p>
  410.  
  411. <pre class="eg">
  412. CC=cc
  413. CFLAGS= -I/home/me/mystuff/include
  414. LDFLAGS=
  415. LIBS= -L/home/me/mystuff/lib -lexpat
  416. xmlapp: xmlapp.o
  417.        $(CC) $(LDFLAGS) -o xmlapp xmlapp.o $(LIBS)
  418. </pre>
  419.  
  420. <p>You'd also have to set the environment variable
  421. <code>LD_LIBRARY_PATH</code> to <code>/home/me/mystuff/lib</code> (or
  422. to <code>${LD_LIBRARY_PATH}:/home/me/mystuff/lib</code> if
  423. LD_LIBRARY_PATH already has some directories in it) in order to run
  424. your application.</p>
  425.  
  426. <h3>Expat Basics</h3>
  427.  
  428. <p>As we saw in the example in the overview, the first step in parsing
  429. an XML document with Expat is to create a parser object. There are <a
  430. href="#creation">three functions</a> in the Expat API for creating a
  431. parser object.  However, only two of these (<code><a href=
  432. "#XML_ParserCreate" >XML_ParserCreate</a></code> and <code><a href=
  433. "#XML_ParserCreateNS" >XML_ParserCreateNS</a></code>) can be used for
  434. constructing a parser for a top-level document.  The object returned
  435. by these functions is an opaque pointer (i.e. "expat.h" declares it as
  436. void *) to data with further internal structure. In order to free the
  437. memory associated with this object you must call <code><a href=
  438. "#XML_ParserFree" >XML_ParserFree</a></code>. Note that if you have
  439. provided any <a href="#userdata">user data</a> that gets stored in the
  440. parser, then your application is responsible for freeing it prior to
  441. calling <code>XML_ParserFree</code>.</p>
  442.  
  443. <p>The objects returned by the parser creation functions are good for
  444. parsing only one XML document or external parsed entity. If your
  445. application needs to parse many XML documents, then it needs to create
  446. a parser object for each one. The best way to deal with this is to
  447. create a higher level object that contains all the default
  448. initialization you want for your parser objects.</p>
  449.  
  450. <p>Walking through a document hierarchy with a stream oriented parser
  451. will require a good stack mechanism in order to keep track of current
  452. context.  For instance, to answer the simple question, "What element
  453. does this text belong to?" requires a stack, since the parser may have
  454. descended into other elements that are children of the current one and
  455. has encountered this text on the way out.</p>
  456.  
  457. <p>The things you're likely to want to keep on a stack are the
  458. currently opened element and it's attributes. You push this
  459. information onto the stack in the start handler and you pop it off in
  460. the end handler.</p>
  461.  
  462. <p>For some tasks, it is sufficient to just keep information on what
  463. the depth of the stack is (or would be if you had one.) The outline
  464. program shown above presents one example. Another such task would be
  465. skipping over a complete element. When you see the start tag for the
  466. element you want to skip, you set a skip flag and record the depth at
  467. which the element started.  When the end tag handler encounters the
  468. same depth, the skipped element has ended and the flag may be
  469. cleared. If you follow the convention that the root element starts at
  470. 1, then you can use the same variable for skip flag and skip
  471. depth.</p>
  472.  
  473. <pre class="eg">
  474. void
  475. init_info(Parseinfo *info) {
  476.   info->skip = 0;
  477.   info->depth = 1;
  478.   /* Other initializations here */
  479. }  /* End of init_info */
  480.  
  481. void XMLCALL
  482. rawstart(void *data, const char *el, const char **attr) {
  483.   Parseinfo *inf = (Parseinfo *) data;
  484.  
  485.   if (! inf->skip) {
  486.     if (should_skip(inf, el, attr)) {
  487.       inf->skip = inf->depth;
  488.     }
  489.     else
  490.       start(inf, el, attr);     /* This does rest of start handling */
  491.   }
  492.  
  493.   inf->depth++;
  494. }  /* End of rawstart */
  495.  
  496. void XMLCALL
  497. rawend(void *data, const char *el) {
  498.   Parseinfo *inf = (Parseinfo *) data;
  499.  
  500.   inf->depth--;
  501.  
  502.   if (! inf->skip)
  503.     end(inf, el);              /* This does rest of end handling */
  504.  
  505.   if (inf->skip == inf->depth)
  506.     inf->skip = 0;
  507. }  /* End rawend */
  508. </pre>
  509.  
  510. <p>Notice in the above example the difference in how depth is
  511. manipulated in the start and end handlers. The end tag handler should
  512. be the mirror image of the start tag handler. This is necessary to
  513. properly model containment. Since, in the start tag handler, we
  514. incremented depth <em>after</em> the main body of start tag code, then
  515. in the end handler, we need to manipulate it <em>before</em> the main
  516. body.  If we'd decided to increment it first thing in the start
  517. handler, then we'd have had to decrement it last thing in the end
  518. handler.</p>
  519.  
  520. <h3 id="userdata">Communicating between handlers</h3>
  521.  
  522. <p>In order to be able to pass information between different handlers
  523. without using globals, you'll need to define a data structure to hold
  524. the shared variables. You can then tell Expat (with the <code><a href=
  525. "#XML_SetUserData" >XML_SetUserData</a></code> function) to pass a
  526. pointer to this structure to the handlers.  This is the first
  527. argument received by most handlers.  In the <a href="#reference"
  528. >reference section</a>, an argument to a callback function is named
  529. <code>userData</code> and have type <code>void *</code> if the user
  530. data is passed; it will have the type <code>XML_Parser</code> if the
  531. parser itself is passed.  When the parser is passed, the user data may
  532. be retrieved using <code><a href="#XML_GetUserData"
  533. >XML_GetUserData</a></code>.</p>
  534.  
  535. <p>One common case where multiple calls to a single handler may need
  536. to communicate using an application data structure is the case when
  537. content passed to the character data handler (set by <code><a href=
  538. "#XML_SetCharacterDataHandler"
  539. >XML_SetCharacterDataHandler</a></code>) needs to be accumulated.  A
  540. common first-time mistake with any of the event-oriented interfaces to
  541. an XML parser is to expect all the text contained in an element to be
  542. reported by a single call to the character data handler.  Expat, like
  543. many other XML parsers, reports such data as a sequence of calls;
  544. there's no way to know when the end of the sequence is reached until a
  545. different callback is made.  A buffer referenced by the user data
  546. structure proves both an effective and convenient place to accumulate
  547. character data.</p>
  548.  
  549. <!-- XXX example needed here -->
  550.  
  551.  
  552. <h3>XML Version</h3>
  553.  
  554. <p>Expat is an XML 1.0 parser, and as such never complains based on
  555. the value of the <code>version</code> pseudo-attribute in the XML
  556. declaration, if present.</p>
  557.  
  558. <p>If an application needs to check the version number (to support
  559. alternate processing), it should use the <code><a href=
  560. "#XML_SetXmlDeclHandler" >XML_SetXmlDeclHandler</a></code> function to
  561. set a handler that uses the information in the XML declaration to
  562. determine what to do.  This example shows how to check that only a
  563. version number of <code>"1.0"</code> is accepted:</p>
  564.  
  565. <pre class="eg">
  566. static int wrong_version;
  567. static XML_Parser parser;
  568.  
  569. static void XMLCALL
  570. xmldecl_handler(void            *userData,
  571.                 const XML_Char  *version,
  572.                 const XML_Char  *encoding,
  573.                 int              standalone)
  574. {
  575.   static const XML_Char Version_1_0[] = {'1', '.', '0', 0};
  576.  
  577.   int i;
  578.  
  579.   for (i = 0; i &lt; (sizeof(Version_1_0) / sizeof(Version_1_0[0])); ++i) {
  580.     if (version[i] != Version_1_0[i]) {
  581.       wrong_version = 1;
  582.       /* also clear all other handlers: */
  583.       XML_SetCharacterDataHandler(parser, NULL);
  584.       ...
  585.       return;
  586.     }
  587.   }
  588.   ...
  589. }
  590. </pre>
  591.  
  592. <h3>Namespace Processing</h3>
  593.  
  594. <p>When the parser is created using the <code><a href=
  595. "#XML_ParserCreateNS" >XML_ParserCreateNS</a></code>, function, Expat
  596. performs namespace processing. Under namespace processing, Expat
  597. consumes <code>xmlns</code> and <code>xmlns:...</code> attributes,
  598. which declare namespaces for the scope of the element in which they
  599. occur. This means that your start handler will not see these
  600. attributes.  Your application can still be informed of these
  601. declarations by setting namespace declaration handlers with <a href=
  602. "#XML_SetNamespaceDeclHandler"
  603. ><code>XML_SetNamespaceDeclHandler</code></a>.</p>
  604.  
  605. <p>Element type and attribute names that belong to a given namespace
  606. are passed to the appropriate handler in expanded form. By default
  607. this expanded form is a concatenation of the namespace URI, the
  608. separator character (which is the 2nd argument to <code><a href=
  609. "#XML_ParserCreateNS" >XML_ParserCreateNS</a></code>), and the local
  610. name (i.e. the part after the colon). Names with undeclared prefixes
  611. are not well-formed when namespace processing is enabled, and will
  612. trigger an error. Unprefixed attribute names are never expanded,
  613. and unprefixed element names are only expanded when they are in the
  614. scope of a default namespace.</p>
  615.  
  616. <p>However if <code><a href= "#XML_SetReturnNSTriplet"
  617. >XML_SetReturnNSTriplet</a></code> has been called with a non-zero
  618. <code>do_nst</code> parameter, then the expanded form for names with
  619. an explicit prefix is a concatenation of: URI, separator, local name,
  620. separator, prefix.</p>
  621.  
  622. <p>You can set handlers for the start of a namespace declaration and
  623. for the end of a scope of a declaration with the <code><a href=
  624. "#XML_SetNamespaceDeclHandler" >XML_SetNamespaceDeclHandler</a></code>
  625. function.  The StartNamespaceDeclHandler is called prior to the start
  626. tag handler and the EndNamespaceDeclHandler is called after the
  627. corresponding end tag that ends the namespace's scope.  The namespace
  628. start handler gets passed the prefix and URI for the namespace.  For a
  629. default namespace declaration (xmlns='...'), the prefix will be null.
  630. The URI will be null for the case where the default namespace is being
  631. unset.  The namespace end handler just gets the prefix for the closing
  632. scope.</p>
  633.  
  634. <p>These handlers are called for each declaration. So if, for
  635. instance, a start tag had three namespace declarations, then the
  636. StartNamespaceDeclHandler would be called three times before the start
  637. tag handler is called, once for each declaration.</p>
  638.  
  639. <h3>Character Encodings</h3>
  640.  
  641. <p>While XML is based on Unicode, and every XML processor is required
  642. to recognized UTF-8 and UTF-16 (1 and 2 byte encodings of Unicode),
  643. other encodings may be declared in XML documents or entities. For the
  644. main document, an XML declaration may contain an encoding
  645. declaration:</p>
  646. <pre>
  647. &lt;?xml version="1.0" encoding="ISO-8859-2"?&gt;
  648. </pre>
  649.  
  650. <p>External parsed entities may begin with a text declaration, which
  651. looks like an XML declaration with just an encoding declaration:</p>
  652. <pre>
  653. &lt;?xml encoding="Big5"?&gt;
  654. </pre>
  655.  
  656. <p>With Expat, you may also specify an encoding at the time of
  657. creating a parser. This is useful when the encoding information may
  658. come from a source outside the document itself (like a higher level
  659. protocol.)</p>
  660.  
  661. <p><a name="builtin_encodings"></a>There are four built-in encodings
  662. in Expat:</p>
  663. <ul>
  664. <li>UTF-8</li>
  665. <li>UTF-16</li>
  666. <li>ISO-8859-1</li>
  667. <li>US-ASCII</li>
  668. </ul>
  669.  
  670. <p>Anything else discovered in an encoding declaration or in the
  671. protocol encoding specified in the parser constructor, triggers a call
  672. to the <code>UnknownEncodingHandler</code>. This handler gets passed
  673. the encoding name and a pointer to an <code>XML_Encoding</code> data
  674. structure. Your handler must fill in this structure and return
  675. <code>XML_STATUS_OK</code> if it knows how to deal with the
  676. encoding. Otherwise the handler should return
  677. <code>XML_STATUS_ERROR</code>.  The handler also gets passed a pointer
  678. to an optional application data structure that you may indicate when
  679. you set the handler.</p>
  680.  
  681. <p>Expat places restrictions on character encodings that it can
  682. support by filling in the <code>XML_Encoding</code> structure.
  683. include file:</p>
  684. <ol>
  685. <li>Every ASCII character that can appear in a well-formed XML document
  686. must be represented by a single byte, and that byte must correspond to
  687. it's ASCII encoding (except for the characters $@\^'{}~)</li>
  688. <li>Characters must be encoded in 4 bytes or less.</li>
  689. <li>All characters encoded must have Unicode scalar values less than or
  690. equal to 65535 (0xFFFF)<em>This does not apply to the built-in support
  691. for UTF-16 and UTF-8</em></li>
  692. <li>No character may be encoded by more that one distinct sequence of
  693. bytes</li>
  694. </ol>
  695.  
  696. <p><code>XML_Encoding</code> contains an array of integers that
  697. correspond to the 1st byte of an encoding sequence. If the value in
  698. the array for a byte is zero or positive, then the byte is a single
  699. byte encoding that encodes the Unicode scalar value contained in the
  700. array. A -1 in this array indicates a malformed byte. If the value is
  701. -2, -3, or -4, then the byte is the beginning of a 2, 3, or 4 byte
  702. sequence respectively. Multi-byte sequences are sent to the convert
  703. function pointed at in the <code>XML_Encoding</code> structure. This
  704. function should return the Unicode scalar value for the sequence or -1
  705. if the sequence is malformed.</p>
  706.  
  707. <p>One pitfall that novice Expat users are likely to fall into is that
  708. although Expat may accept input in various encodings, the strings that
  709. it passes to the handlers are always encoded in UTF-8 or UTF-16
  710. (depending on how Expat was compiled). Your application is responsible
  711. for any translation of these strings into other encodings.</p>
  712.  
  713. <h3>Handling External Entity References</h3>
  714.  
  715. <p>Expat does not read or parse external entities directly. Note that
  716. any external DTD is a special case of an external entity.  If you've
  717. set no <code>ExternalEntityRefHandler</code>, then external entity
  718. references are silently ignored. Otherwise, it calls your handler with
  719. the information needed to read and parse the external entity.</p>
  720.  
  721. <p>Your handler isn't actually responsible for parsing the entity, but
  722. it is responsible for creating a subsidiary parser with <code><a href=
  723. "#XML_ExternalEntityParserCreate"
  724. >XML_ExternalEntityParserCreate</a></code> that will do the job. This
  725. returns an instance of <code>XML_Parser</code> that has handlers and
  726. other data structures initialized from the parent parser. You may then
  727. use <code><a href= "#XML_Parse" >XML_Parse</a></code> or <code><a
  728. href= "#XML_ParseBuffer">XML_ParseBuffer</a></code> calls against this
  729. parser.  Since external entities my refer to other external entities,
  730. your handler should be prepared to be called recursively.</p>
  731.  
  732. <h3>Parsing DTDs</h3>
  733.  
  734. <p>In order to parse parameter entities, before starting the parse,
  735. you must call <code><a href= "#XML_SetParamEntityParsing"
  736. >XML_SetParamEntityParsing</a></code> with one of the following
  737. arguments:</p>
  738. <dl>
  739. <dt><code>XML_PARAM_ENTITY_PARSING_NEVER</code></dt>
  740. <dd>Don't parse parameter entities or the external subset</dd>
  741. <dt><code>XML_PARAM_ENTITY_PARSING_UNLESS_STANDALONE</code></dt>
  742. <dd>Parse parameter entites and the external subset unless
  743. <code>standalone</code> was set to "yes" in the XML declaration.</dd>
  744. <dt><code>XML_PARAM_ENTITY_PARSING_ALWAYS</code></dt>
  745. <dd>Always parse parameter entities and the external subset</dd>
  746. </dl>
  747.  
  748. <p>In order to read an external DTD, you also have to set an external
  749. entity reference handler as described above.</p>
  750.  
  751. <h3 id="stop-resume">Temporarily Stopping Parsing</h3>
  752.  
  753. <p>Expat 1.95.8 introduces a new feature: its now possible to stop
  754. parsing temporarily from within a handler function, even if more data
  755. has already been passed into the parser.  Applications for this
  756. include</p>
  757.  
  758. <ul>
  759.   <li>Supporting the <a href= "http://www.w3.org/TR/xinclude/"
  760.   >XInclude</a> specification.</li>
  761.  
  762.   <li>Delaying further processing until additional information is
  763.   available from some other source.</li>
  764.  
  765.   <li>Adjusting processor load as task priorities shift within an
  766.   application.</li>
  767.  
  768.   <li>Stopping parsing completely (simply free or reset the parser
  769.   instead of resuming in the outer parsing loop).  This can be useful
  770.   if a application-domain error is found in the XML being parsed or if
  771.   the result of the parse is determined not to be useful after
  772.   all.</li>
  773. </ul>
  774.  
  775. <p>To take advantage of this feature, the main parsing loop of an
  776. application needs to support this specifically.  It cannot be
  777. supported with a parsing loop compatible with Expat 1.95.7 or
  778. earlier (though existing loops will continue to work without
  779. supporting the stop/resume feature).</p>
  780.  
  781. <p>An application that uses this feature for a single parser will have
  782. the rough structure (in pseudo-code):</p>
  783.  
  784. <pre class="pseudocode">
  785. fd = open_input()
  786. p = create_parser()
  787.  
  788. if parse_xml(p, fd) {
  789.   /* suspended */
  790.  
  791.   int suspended = 1;
  792.  
  793.   while (suspended) {
  794.     do_something_else()
  795.     if ready_to_resume() {
  796.       suspended = continue_parsing(p, fd);
  797.     }
  798.   }
  799. }
  800. </pre>
  801.  
  802. <p>An application that may resume any of several parsers based on
  803. input (either from the XML being parsed or some other source) will
  804. certainly have more interesting control structures.</p>
  805.  
  806. <p>This C function could be used for the <code>parse_xml</code>
  807. function mentioned in the pseudo-code above:</p>
  808.  
  809. <pre class="eg">
  810. #define BUFF_SIZE 10240
  811.  
  812. /* Parse a document from the open file descriptor 'fd' until the parse
  813.    is complete (the document has been completely parsed, or there's
  814.   been an error), or the parse is stopped.  Return non-zero when
  815.   the parse is merely suspended.
  816. */
  817. int
  818. parse_xml(XML_Parser p, int fd)
  819. {
  820.  for (;;) {
  821.    int last_chunk;
  822.    int bytes_read;
  823.    enum XML_Status status;
  824.  
  825.    void *buff = XML_GetBuffer(p, BUFF_SIZE);
  826.    if (buff == NULL) {
  827.      /* handle error... */
  828.      return 0;
  829.    }
  830.    bytes_read = read(fd, buff, BUFF_SIZE);
  831.    if (bytes_read &lt; 0) {
  832.      /* handle error... */
  833.      return 0;
  834.    }
  835.    status = XML_ParseBuffer(p, bytes_read, bytes_read == 0);
  836.    switch (status) {
  837.      case XML_STATUS_ERROR:
  838.        /* handle error... */
  839.        return 0;
  840.      case XML_STATUS_SUSPENDED:
  841.        return 1;
  842.    }
  843.    if (bytes_read == 0)
  844.      return 0;
  845.  }
  846. }
  847. </pre>
  848.  
  849. <p>The corresponding <code>continue_parsing</code> function is
  850. somewhat simpler, since it only need deal with the return code from
  851. <code><a href= "#XML_ResumeParser">XML_ResumeParser</a></code>; it can
  852. delegate the input handling to the <code>parse_xml</code>
  853. function:</p>
  854.  
  855. <pre class="eg">
  856. /* Continue parsing a document which had been suspended.  The 'p' and
  857.   'fd' arguments are the same as passed to parse_xml().  Return
  858.   non-zero when the parse is suspended.
  859. */
  860. int
  861. continue_parsing(XML_Parser p, int fd)
  862. {
  863.  enum XML_Status status = XML_ResumeParser(p);
  864.  switch (status) {
  865.    case XML_STATUS_ERROR:
  866.      /* handle error... */
  867.      return 0;
  868.    case XML_ERROR_NOT_SUSPENDED:
  869.      /* handle error... */
  870.      return 0;.
  871.    case XML_STATUS_SUSPENDED:
  872.      return 1;
  873.  }
  874.  return parse_xml(p, fd);
  875. }
  876. </pre>
  877.  
  878. <p>Now that we've seen what a mess the top-level parsing loop can
  879. become, what have we gained?  Very simply, we can now use the <code><a
  880. href= "#XML_StopParser" >XML_StopParser</a></code> function to stop
  881. parsing, without having to go to great lengths to avoid additional
  882. processing that we're expecting to ignore.  As a bonus, we get to stop
  883. parsing <em>temporarily</em>, and come back to it when we're
  884. ready.</p>
  885.  
  886. <p>To stop parsing from a handler function, use the <code><a href=
  887. "#XML_StopParser" >XML_StopParser</a></code> function.  This function
  888. takes two arguments; the parser being stopped and a flag indicating
  889. whether the parse can be resumed in the future.</p>
  890.  
  891. <!-- XXX really need more here -->
  892.  
  893.  
  894. <hr />
  895. <!-- ================================================================ -->
  896.  
  897. <h2><a name="reference">Expat Reference</a></h2>
  898.  
  899. <h3><a name="creation">Parser Creation</a></h3>
  900.  
  901. <pre class="fcndec" id="XML_ParserCreate">
  902. XML_Parser XMLCALL
  903. XML_ParserCreate(const XML_Char *encoding);
  904. </pre>
  905. <div class="fcndef">
  906. Construct a new parser. If encoding is non-null, it specifies a
  907. character encoding to use for the document. This overrides the document
  908. encoding declaration. There are four built-in encodings:
  909. <ul>
  910. <li>US-ASCII</li>
  911. <li>UTF-8</li>
  912. <li>UTF-16</li>
  913. <li>ISO-8859-1</li>
  914. </ul>
  915. Any other value will invoke a call to the UnknownEncodingHandler.
  916. </div>
  917.  
  918. <pre class="fcndec" id="XML_ParserCreateNS">
  919. XML_Parser XMLCALL
  920. XML_ParserCreateNS(const XML_Char *encoding,
  921.                    XML_Char sep);
  922. </pre>
  923. <div class="fcndef">
  924. Constructs a new parser that has namespace processing in effect. Namespace
  925. expanded element names and attribute names are returned as a concatenation
  926. of the namespace URI, <em>sep</em>, and the local part of the name. This
  927. means that you should pick a character for <em>sep</em> that can't be part
  928. of an URI. Since Expat does not check namespace URIs for conformance, the
  929. only safe choice for a namespace separator is a character that is illegal
  930. in XML. For instance, <code>'\xFF'</code> is not legal in UTF-8, and
  931. <code>'\xFFFF'</code> is not legal in UTF-16. There is a special case when
  932. <em>sep</em> is the null character <code>'\0'</code>: the namespace URI and
  933. the local part will be concatenated without any separator - this is intended
  934. to support RDF processors. It is a programming error to use the null separator
  935. with <a href= "#XML_SetReturnNSTriplet">namespace triplets</a>.</div>
  936.  
  937. <pre class="fcndec" id="XML_ParserCreate_MM">
  938. XML_Parser XMLCALL
  939. XML_ParserCreate_MM(const XML_Char *encoding,
  940.                    const XML_Memory_Handling_Suite *ms,
  941.                     const XML_Char *sep);
  942. </pre>
  943. <pre class="signature">
  944. typedef struct {
  945.  void *(XMLCALL *malloc_fcn)(size_t size);
  946.  void *(XMLCALL *realloc_fcn)(void *ptr, size_t size);
  947.  void (XMLCALL *free_fcn)(void *ptr);
  948. } XML_Memory_Handling_Suite;
  949. </pre>
  950. <div class="fcndef">
  951. <p>Construct a new parser using the suite of memory handling functions
  952. specified in <code>ms</code>. If <code>ms</code> is NULL, then use the
  953. standard set of memory management functions. If <code>sep</code> is
  954. non NULL, then namespace processing is enabled in the created parser
  955. and the character pointed at by sep is used as the separator between
  956. the namespace URI and the local part of the name.</p>
  957. </div>
  958.  
  959. <pre class="fcndec" id="XML_ExternalEntityParserCreate">
  960. XML_Parser XMLCALL
  961. XML_ExternalEntityParserCreate(XML_Parser p,
  962.                               const XML_Char *context,
  963.                               const XML_Char *encoding);
  964. </pre>
  965. <div class="fcndef">
  966. Construct a new <code>XML_Parser</code> object for parsing an external
  967. general entity. Context is the context argument passed in a call to a
  968. ExternalEntityRefHandler. Other state information such as handlers,
  969. user data, namespace processing is inherited from the parser passed as
  970. the 1st argument. So you shouldn't need to call any of the behavior
  971. changing functions on this parser (unless you want it to act
  972. differently than the parent parser).
  973. </div>
  974.  
  975. <pre class="fcndec" id="XML_ParserFree">
  976. void XMLCALL
  977. XML_ParserFree(XML_Parser p);
  978. </pre>
  979. <div class="fcndef">
  980. Free memory used by the parser. Your application is responsible for
  981. freeing any memory associated with <a href="#userdata">user data</a>.
  982. </div>
  983.  
  984. <pre class="fcndec" id="XML_ParserReset">
  985. XML_Bool XMLCALL
  986. XML_ParserReset(XML_Parser p,
  987.                 const XML_Char *encoding);
  988. </pre>
  989. <div class="fcndef">
  990. Clean up the memory structures maintained by the parser so that it may
  991. be used again.  After this has been called, <code>parser</code> is
  992. ready to start parsing a new document.  All handlers are cleared from
  993. the parser, except for the unknownEncodingHandler.  The parser's external
  994. state is re-initialized except for the values of ns and ns_triplets.
  995. This function may not be used on a parser created using <code><a href=
  996. "#XML_ExternalEntityParserCreate" >XML_ExternalEntityParserCreate</a
  997. ></code>; it will return <code>XML_FALSE</code> in that case.  Returns
  998. <code>XML_TRUE</code> on success.  Your application is responsible for
  999. dealing with any memory associated with <a href="#userdata">user data</a>.
  1000. </div>
  1001.  
  1002. <h3><a name="parsing">Parsing</a></h3>
  1003.  
  1004. <p>To state the obvious: the three parsing functions <code><a href=
  1005. "#XML_Parse" >XML_Parse</a></code>, <code><a href= "#XML_ParseBuffer">
  1006. XML_ParseBuffer</a></code> and <code><a href= "#XML_GetBuffer">
  1007. XML_GetBuffer</a></code> must not be called from within a handler
  1008. unless they operate on a separate parser instance, that is, one that
  1009. did not call the handler. For example, it is OK to call the parsing
  1010. functions from within an <code>XML_ExternalEntityRefHandler</code>,
  1011. if they apply to the parser created by
  1012. <code><a href= "#XML_ExternalEntityParserCreate"
  1013. >XML_ExternalEntityParserCreate</a></code>.</p>
  1014.  
  1015. <p>Note: the <code>len</code> argument passed to these functions
  1016. should be considerably less than the maximum value for an integer,
  1017. as it could create an integer overflow situation if the added
  1018. lengths of a buffer and the unprocessed portion of the previous buffer
  1019. exceed the maximum integer value. Input data at the end of a buffer
  1020. will remain unprocessed if it is part of an XML token for which the
  1021. end is not part of that buffer.</p>
  1022.  
  1023. <pre class="fcndec" id="XML_Parse">
  1024. enum XML_Status XMLCALL
  1025. XML_Parse(XML_Parser p,
  1026.          const char *s,
  1027.          int len,
  1028.          int isFinal);
  1029. </pre>
  1030. <pre class="signature">
  1031. enum XML_Status {
  1032.  XML_STATUS_ERROR = 0,
  1033.  XML_STATUS_OK = 1
  1034. };
  1035. </pre>
  1036. <div class="fcndef">
  1037. Parse some more of the document. The string <code>s</code> is a buffer
  1038. containing part (or perhaps all) of the document. The number of bytes of s
  1039. that are part of the document is indicated by <code>len</code>. This means
  1040. that <code>s</code> doesn't have to be null terminated. It also means that
  1041. if <code>len</code> is larger than the number of bytes in the block of
  1042. memory that <code>s</code> points at, then a memory fault is likely. The
  1043. <code>isFinal</code> parameter informs the parser that this is the last
  1044. piece of the document. Frequently, the last piece is empty (i.e.
  1045. <code>len</code> is zero.)
  1046. If a parse error occurred, it returns <code>XML_STATUS_ERROR</code>.
  1047. Otherwise it returns <code>XML_STATUS_OK</code> value.
  1048. </div>
  1049.  
  1050. <pre class="fcndec" id="XML_ParseBuffer">
  1051. enum XML_Status XMLCALL
  1052. XML_ParseBuffer(XML_Parser p,
  1053.                 int len,
  1054.                 int isFinal);
  1055. </pre>
  1056. <div class="fcndef">
  1057. This is just like <code><a href= "#XML_Parse" >XML_Parse</a></code>,
  1058. except in this case Expat provides the buffer.  By obtaining the
  1059. buffer from Expat with the <code><a href= "#XML_GetBuffer"
  1060. >XML_GetBuffer</a></code> function, the application can avoid double
  1061. copying of the input.
  1062. </div>
  1063.  
  1064. <pre class="fcndec" id="XML_GetBuffer">
  1065. void * XMLCALL
  1066. XML_GetBuffer(XML_Parser p,
  1067.               int len);
  1068. </pre>
  1069. <div class="fcndef">
  1070. Obtain a buffer of size <code>len</code> to read a piece of the document
  1071. into. A NULL value is returned if Expat can't allocate enough memory for
  1072. this buffer. This has to be called prior to every call to
  1073. <code><a href= "#XML_ParseBuffer" >XML_ParseBuffer</a></code>. A
  1074. typical use would look like this:
  1075.  
  1076. <pre class="eg">
  1077. for (;;) {
  1078.  int bytes_read;
  1079.  void *buff = XML_GetBuffer(p, BUFF_SIZE);
  1080.  if (buff == NULL) {
  1081.    /* handle error */
  1082.  }
  1083.  
  1084.  bytes_read = read(docfd, buff, BUFF_SIZE);
  1085.  if (bytes_read &lt; 0) {
  1086.    /* handle error */
  1087.  }
  1088.  
  1089.  if (! XML_ParseBuffer(p, bytes_read, bytes_read == 0)) {
  1090.    /* handle parse error */
  1091.  }
  1092.  
  1093.  if (bytes_read == 0)
  1094.    break;
  1095. }
  1096. </pre>
  1097. </div>
  1098.  
  1099. <pre class="fcndec" id="XML_StopParser">
  1100. enum XML_Status XMLCALL
  1101. XML_StopParser(XML_Parser p,
  1102.               XML_Bool resumable);
  1103. </pre>
  1104. <div class="fcndef">
  1105.  
  1106. <p>Stops parsing, causing <code><a href= "#XML_Parse"
  1107. >XML_Parse</a></code> or <code><a href= "#XML_ParseBuffer"
  1108. >XML_ParseBuffer</a></code> to return.  Must be called from within a
  1109. call-back handler, except when aborting (when <code>resumable</code>
  1110. is <code>XML_FALSE</code>) an already suspended parser.  Some
  1111. call-backs may still follow because they would otherwise get
  1112. lost, including
  1113. <ul>
  1114.  <li> the end element handler for empty elements when stopped in the
  1115.       start element handler,</li>
  1116.  <li> the end namespace declaration handler when stopped in the end
  1117.       element handler,</li>
  1118.  <li> the character data handler when stopped in the character data handler
  1119.       while making multiple call-backs on a contiguous chunk of characters,</li>
  1120. </ul>
  1121. and possibly others.</p>
  1122.  
  1123. <p>This can be called from most handlers, including DTD related
  1124. call-backs, except when parsing an external parameter entity and
  1125. <code>resumable</code> is <code>XML_TRUE</code>.  Returns
  1126. <code>XML_STATUS_OK</code> when successful,
  1127. <code>XML_STATUS_ERROR</code> otherwise.  The possible error codes
  1128. are:</p>
  1129. <dl>
  1130.  <dt><code>XML_ERROR_SUSPENDED</code></dt>
  1131.  <dd>when suspending an already suspended parser.</dd>
  1132.  <dt><code>XML_ERROR_FINISHED</code></dt>
  1133.  <dd>when the parser has already finished.</dd>
  1134.  <dt><code>XML_ERROR_SUSPEND_PE</code></dt>
  1135.  <dd>when suspending while parsing an external PE.</dd>
  1136. </dl>
  1137.  
  1138. <p>Since the stop/resume feature requires application support in the
  1139. outer parsing loop, it is an error to call this function for a parser
  1140. not being handled appropriately; see <a href= "#stop-resume"
  1141. >Temporarily Stopping Parsing</a> for more information.</p>
  1142.  
  1143. <p>When <code>resumable</code> is <code>XML_TRUE</code> then parsing
  1144. is <em>suspended</em>, that is, <code><a href= "#XML_Parse"
  1145. >XML_Parse</a></code> and <code><a href= "#XML_ParseBuffer"
  1146. >XML_ParseBuffer</a></code> return <code>XML_STATUS_SUSPENDED</code>.
  1147. Otherwise, parsing is <em>aborted</em>, that is, <code><a href=
  1148. "#XML_Parse" >XML_Parse</a></code> and <code><a href=
  1149. "#XML_ParseBuffer" >XML_ParseBuffer</a></code> return
  1150. <code>XML_STATUS_ERROR</code> with error code
  1151. <code>XML_ERROR_ABORTED</code>.</p>
  1152.  
  1153. <p><strong>Note:</strong>
  1154. This will be applied to the current parser instance only, that is, if
  1155. there is a parent parser then it will continue parsing when the
  1156. external entity reference handler returns.  It is up to the
  1157. implementation of that handler to call <code><a href=
  1158. "#XML_StopParser" >XML_StopParser</a></code> on the parent parser
  1159. (recursively), if one wants to stop parsing altogether.</p>
  1160.  
  1161. <p>When suspended, parsing can be resumed by calling <code><a href=
  1162. "#XML_ResumeParser" >XML_ResumeParser</a></code>.</p>
  1163.  
  1164. <p>New in Expat 1.95.8.</p>
  1165. </div>
  1166.  
  1167. <pre class="fcndec" id="XML_ResumeParser">
  1168. enum XML_Status XMLCALL
  1169. XML_ResumeParser(XML_Parser p);
  1170. </pre>
  1171. <div class="fcndef">
  1172. <p>Resumes parsing after it has been suspended with <code><a href=
  1173. "#XML_StopParser" >XML_StopParser</a></code>.  Must not be called from
  1174. within a handler call-back.  Returns same status codes as <code><a
  1175. href= "#XML_Parse">XML_Parse</a></code> or <code><a href=
  1176. "#XML_ParseBuffer" >XML_ParseBuffer</a></code>.  An additional error
  1177. code, <code>XML_ERROR_NOT_SUSPENDED</code>, will be returned if the
  1178. parser was not currently suspended.</p>
  1179.  
  1180. <p><strong>Note:</strong>
  1181. This must be called on the most deeply nested child parser instance
  1182. first, and on its parent parser only after the child parser has
  1183. finished, to be applied recursively until the document entity's parser
  1184. is restarted.  That is, the parent parser will not resume by itself
  1185. and it is up to the application to call <code><a href=
  1186. "#XML_ResumeParser" >XML_ResumeParser</a></code> on it at the
  1187. appropriate moment.</p>
  1188.  
  1189. <p>New in Expat 1.95.8.</p>
  1190. </div>
  1191.  
  1192. <pre class="fcndec" id="XML_GetParsingStatus">
  1193. void XMLCALL
  1194. XML_GetParsingStatus(XML_Parser p,
  1195.                      XML_ParsingStatus *status);
  1196. </pre>
  1197. <pre class="signature">
  1198. enum XML_Parsing {
  1199.   XML_INITIALIZED,
  1200.   XML_PARSING,
  1201.   XML_FINISHED,
  1202.   XML_SUSPENDED
  1203. };
  1204.  
  1205. typedef struct {
  1206.   enum XML_Parsing parsing;
  1207.   XML_Bool finalBuffer;
  1208. } XML_ParsingStatus;
  1209. </pre>
  1210. <div class="fcndef">
  1211. <p>Returns status of parser with respect to being initialized,
  1212. parsing, finished, or suspended, and whether the final buffer is being
  1213. processed.  The <code>status</code> parameter <em>must not</em> be
  1214. NULL.</p>
  1215.  
  1216. <p>New in Expat 1.95.8.</p>
  1217. </div>
  1218.  
  1219.  
  1220. <h3><a name="setting">Handler Setting</a></h3>
  1221.  
  1222. <p>Although handlers are typically set prior to parsing and left alone, an
  1223. application may choose to set or change the handler for a parsing event
  1224. while the parse is in progress. For instance, your application may choose
  1225. to ignore all text not descended from a <code>para</code> element. One
  1226. way it could do this is to set the character handler when a para start tag
  1227. is seen, and unset it for the corresponding end tag.</p>
  1228.  
  1229. <p>A handler may be <em>unset</em> by providing a NULL pointer to the
  1230. appropriate handler setter. None of the handler setting functions have
  1231. a return value.</p>
  1232.  
  1233. <p>Your handlers will be receiving strings in arrays of type
  1234. <code>XML_Char</code>. This type is conditionally defined in expat.h as
  1235. either <code>char</code>, <code>wchar_t</code> or <code>unsigned short</code>.
  1236. The former implies UTF-8 encoding, the latter two imply UTF-16 encoding.
  1237. Note that you'll receive them in this form independent of the original
  1238. encoding of the document.</p>
  1239.  
  1240. <div class="handler">
  1241. <pre class="setter" id="XML_SetStartElementHandler">
  1242. void XMLCALL
  1243. XML_SetStartElementHandler(XML_Parser p,
  1244.                           XML_StartElementHandler start);
  1245. </pre>
  1246. <pre class="signature">
  1247. typedef void
  1248. (XMLCALL *XML_StartElementHandler)(void *userData,
  1249.                                   const XML_Char *name,
  1250.                                   const XML_Char **atts);
  1251. </pre>
  1252. <p>Set handler for start (and empty) tags. Attributes are passed to the start
  1253. handler as a pointer to a vector of char pointers. Each attribute seen in
  1254. a start (or empty) tag occupies 2 consecutive places in this vector: the
  1255. attribute name followed by the attribute value. These pairs are terminated
  1256. by a null pointer.</p>
  1257. <p>Note that an empty tag generates a call to both start and end handlers
  1258. (in that order).</p>
  1259. </div>
  1260.  
  1261. <div class="handler">
  1262. <pre class="setter" id="XML_SetEndElementHandler">
  1263. void XMLCALL
  1264. XML_SetEndElementHandler(XML_Parser p,
  1265.                         XML_EndElementHandler);
  1266. </pre>
  1267. <pre class="signature">
  1268. typedef void
  1269. (XMLCALL *XML_EndElementHandler)(void *userData,
  1270.                                 const XML_Char *name);
  1271. </pre>
  1272. <p>Set handler for end (and empty) tags. As noted above, an empty tag
  1273. generates a call to both start and end handlers.</p>
  1274. </div>
  1275.  
  1276. <div class="handler">
  1277. <pre class="setter" id="XML_SetElementHandler">
  1278. void XMLCALL
  1279. XML_SetElementHandler(XML_Parser p,
  1280.                      XML_StartElementHandler start,
  1281.                      XML_EndElementHandler end);
  1282. </pre>
  1283. <p>Set handlers for start and end tags with one call.</p>
  1284. </div>
  1285.  
  1286. <div class="handler">
  1287. <pre class="setter" id="XML_SetCharacterDataHandler">
  1288. void XMLCALL
  1289. XML_SetCharacterDataHandler(XML_Parser p,
  1290.                            XML_CharacterDataHandler charhndl)
  1291. </pre>
  1292. <pre class="signature">
  1293. typedef void
  1294. (XMLCALL *XML_CharacterDataHandler)(void *userData,
  1295.                                    const XML_Char *s,
  1296.                                    int len);
  1297. </pre>
  1298. <p>Set a text handler. The string your handler receives
  1299. is <em>NOT nul-terminated</em>. You have to use the length argument
  1300. to deal with the end of the string. A single block of contiguous text
  1301. free of markup may still result in a sequence of calls to this handler.
  1302. In other words, if you're searching for a pattern in the text, it may
  1303. be split across calls to this handler. Note: Setting this handler to NULL
  1304. may <em>NOT immediately</em> terminate call-backs if the parser is currently
  1305. processing such a single block of contiguous markup-free text, as the parser
  1306. will continue calling back until the end of the block is reached.</p>
  1307. </div>
  1308.  
  1309. <div class="handler">
  1310. <pre class="setter" id="XML_SetProcessingInstructionHandler">
  1311. void XMLCALL
  1312. XML_SetProcessingInstructionHandler(XML_Parser p,
  1313.                                     XML_ProcessingInstructionHandler proc)
  1314. </pre>
  1315. <pre class="signature">
  1316. typedef void
  1317. (XMLCALL *XML_ProcessingInstructionHandler)(void *userData,
  1318.                                             const XML_Char *target,
  1319.                                             const XML_Char *data);
  1320.  
  1321. </pre>
  1322. <p>Set a handler for processing instructions. The target is the first word
  1323. in the processing instruction. The data is the rest of the characters in
  1324. it after skipping all whitespace after the initial word.</p>
  1325. </div>
  1326.  
  1327. <div class="handler">
  1328. <pre class="setter" id="XML_SetCommentHandler">
  1329. void XMLCALL
  1330. XML_SetCommentHandler(XML_Parser p,
  1331.                       XML_CommentHandler cmnt)
  1332. </pre>
  1333. <pre class="signature">
  1334. typedef void
  1335. (XMLCALL *XML_CommentHandler)(void *userData,
  1336.                               const XML_Char *data);
  1337. </pre>
  1338. <p>Set a handler for comments. The data is all text inside the comment
  1339. delimiters.</p>
  1340. </div>
  1341.  
  1342. <div class="handler">
  1343. <pre class="setter" id="XML_SetStartCdataSectionHandler">
  1344. void XMLCALL
  1345. XML_SetStartCdataSectionHandler(XML_Parser p,
  1346.                                 XML_StartCdataSectionHandler start);
  1347. </pre>
  1348. <pre class="signature">
  1349. typedef void
  1350. (XMLCALL *XML_StartCdataSectionHandler)(void *userData);
  1351. </pre>
  1352. <p>Set a handler that gets called at the beginning of a CDATA section.</p>
  1353. </div>
  1354.  
  1355. <div class="handler">
  1356. <pre class="setter" id="XML_SetEndCdataSectionHandler">
  1357. void XMLCALL
  1358. XML_SetEndCdataSectionHandler(XML_Parser p,
  1359.                               XML_EndCdataSectionHandler end);
  1360. </pre>
  1361. <pre class="signature">
  1362. typedef void
  1363. (XMLCALL *XML_EndCdataSectionHandler)(void *userData);
  1364. </pre>
  1365. <p>Set a handler that gets called at the end of a CDATA section.</p>
  1366. </div>
  1367.  
  1368. <div class="handler">
  1369. <pre class="setter" id="XML_SetCdataSectionHandler">
  1370. void XMLCALL
  1371. XML_SetCdataSectionHandler(XML_Parser p,
  1372.                            XML_StartCdataSectionHandler start,
  1373.                            XML_EndCdataSectionHandler end)
  1374. </pre>
  1375. <p>Sets both CDATA section handlers with one call.</p>
  1376. </div>
  1377.  
  1378. <div class="handler">
  1379. <pre class="setter" id="XML_SetDefaultHandler">
  1380. void XMLCALL
  1381. XML_SetDefaultHandler(XML_Parser p,
  1382.                       XML_DefaultHandler hndl)
  1383. </pre>
  1384. <pre class="signature">
  1385. typedef void
  1386. (XMLCALL *XML_DefaultHandler)(void *userData,
  1387.                               const XML_Char *s,
  1388.                               int len);
  1389. </pre>
  1390.  
  1391. <p>Sets a handler for any characters in the document which wouldn't
  1392. otherwise be handled. This includes both data for which no handlers
  1393. can be set (like some kinds of DTD declarations) and data which could
  1394. be reported but which currently has no handler set.  The characters
  1395. are passed exactly as they were present in the XML document except
  1396. that they will be encoded in UTF-8 or UTF-16. Line boundaries are not
  1397. normalized. Note that a byte order mark character is not passed to the
  1398. default handler. There are no guarantees about how characters are
  1399. divided between calls to the default handler: for example, a comment
  1400. might be split between multiple calls.  Setting the handler with
  1401. this call has the side effect of turning off expansion of references
  1402. to internally defined general entities. Instead these references are
  1403. passed to the default handler.</p>
  1404.  
  1405. <p>See also <code><a
  1406. href="#XML_DefaultCurrent">XML_DefaultCurrent</a></code>.</p>
  1407. </div>
  1408.  
  1409. <div class="handler">
  1410. <pre class="setter" id="XML_SetDefaultHandlerExpand">
  1411. void XMLCALL
  1412. XML_SetDefaultHandlerExpand(XML_Parser p,
  1413.                            XML_DefaultHandler hndl)
  1414. </pre>
  1415. <pre class="signature">
  1416. typedef void
  1417. (XMLCALL *XML_DefaultHandler)(void *userData,
  1418.                              const XML_Char *s,
  1419.                              int len);
  1420. </pre>
  1421. <p>This sets a default handler, but doesn't inhibit the expansion of
  1422. internal entity references.  The entity reference will not be passed
  1423. to the default handler.</p>
  1424.  
  1425. <p>See also <code><a
  1426. href="#XML_DefaultCurrent">XML_DefaultCurrent</a></code>.</p>
  1427. </div>
  1428.  
  1429. <div class="handler">
  1430. <pre class="setter" id="XML_SetExternalEntityRefHandler">
  1431. void XMLCALL
  1432. XML_SetExternalEntityRefHandler(XML_Parser p,
  1433.                                 XML_ExternalEntityRefHandler hndl)
  1434. </pre>
  1435. <pre class="signature">
  1436. typedef int
  1437. (XMLCALL *XML_ExternalEntityRefHandler)(XML_Parser p,
  1438.                                         const XML_Char *context,
  1439.                                         const XML_Char *base,
  1440.                                         const XML_Char *systemId,
  1441.                                         const XML_Char *publicId);
  1442. </pre>
  1443. <p>Set an external entity reference handler. This handler is also
  1444. called for processing an external DTD subset if parameter entity parsing
  1445. is in effect. (See <a href="#XML_SetParamEntityParsing">
  1446. <code>XML_SetParamEntityParsing</code></a>.)</p>
  1447.  
  1448. <p>The <code>context</code> parameter specifies the parsing context in
  1449. the format expected by the <code>context</code> argument to <code><a
  1450. href="#XML_ExternalEntityParserCreate"
  1451. >XML_ExternalEntityParserCreate</a></code>.  <code>code</code> is
  1452. valid only until the handler returns, so if the referenced entity is
  1453. to be parsed later, it must be copied.  <code>context</code> is NULL
  1454. only when the entity is a parameter entity, which is how one can
  1455. differentiate between general and parameter entities.</p>
  1456.  
  1457. <p>The <code>base</code> parameter is the base to use for relative
  1458. system identifiers.  It is set by <code><a
  1459. href="#XML_SetBase">XML_SetBase</a></code> and may be NULL. The
  1460. <code>publicId</code> parameter is the public id given in the entity
  1461. declaration and may be NULL.  <code>systemId</code> is the system
  1462. identifier specified in the entity declaration and is never NULL.</p>
  1463.  
  1464. <p>There are a couple of ways in which this handler differs from
  1465. others.  First, this handler returns a status indicator (an
  1466. integer). <code>XML_STATUS_OK</code> should be returned for successful
  1467. handling of the external entity reference.  Returning
  1468. <code>XML_STATUS_ERROR</code> indicates failure, and causes the
  1469. calling parser to return an
  1470. <code>XML_ERROR_EXTERNAL_ENTITY_HANDLING</code> error.</p>
  1471.  
  1472. <p>Second, instead of having the user data as its first argument, it
  1473. receives the parser that encountered the entity reference. This, along
  1474. with the context parameter, may be used as arguments to a call to
  1475. <code><a href= "#XML_ExternalEntityParserCreate"
  1476. >XML_ExternalEntityParserCreate</a></code>.  Using the returned
  1477. parser, the body of the external entity can be recursively parsed.</p>
  1478.  
  1479. <p>Since this handler may be called recursively, it should not be saving
  1480. information into global or static variables.</p>
  1481. </div>
  1482.  
  1483. <pre class="fcndec" id="XML_SetExternalEntityRefHandlerArg">
  1484. void XMLCALL
  1485. XML_SetExternalEntityRefHandlerArg(XML_Parser p,
  1486.                                    void *arg)
  1487. </pre>
  1488. <div class="fcndef">
  1489. <p>Set the argument passed to the ExternalEntityRefHandler.  If
  1490. <code>arg</code> is not NULL, it is the new value passed to the
  1491. handler set using <code><a href="#XML_SetExternalEntityRefHandler"
  1492. >XML_SetExternalEntityRefHandler</a></code>; if <code>arg</code> is
  1493. NULL, the argument passed to the handler function will be the parser
  1494. object itself.</p>
  1495.  
  1496. <p><strong>Note:</strong>
  1497. The type of <code>arg</code> and the type of the first argument to the
  1498. ExternalEntityRefHandler do not match.  This function takes a
  1499. <code>void *</code> to be passed to the handler, while the handler
  1500. accepts an <code>XML_Parser</code>.  This is a historical accident,
  1501. but will not be corrected before Expat 2.0 (at the earliest) to avoid
  1502. causing compiler warnings for code that's known to work with this
  1503. API.  It is the responsibility of the application code to know the
  1504. actual type of the argument passed to the handler and to manage it
  1505. properly.</p>
  1506. </div>
  1507.  
  1508. <div class="handler">
  1509. <pre class="setter" id="XML_SetSkippedEntityHandler">
  1510. void XMLCALL
  1511. XML_SetSkippedEntityHandler(XML_Parser p,
  1512.                            XML_SkippedEntityHandler handler)
  1513. </pre>
  1514. <pre class="signature">
  1515. typedef void
  1516. (XMLCALL *XML_SkippedEntityHandler)(void *userData,
  1517.                                    const XML_Char *entityName,
  1518.                                    int is_parameter_entity);
  1519. </pre>
  1520. <p>Set a skipped entity handler. This is called in two situations:</p>
  1521. <ol>
  1522.   <li>An entity reference is encountered for which no declaration
  1523.       has been read <em>and</em> this is not an error.</li>
  1524.   <li>An internal entity reference is read, but not expanded, because
  1525.       <a href="#XML_SetDefaultHandler"><code>XML_SetDefaultHandler</code></a>
  1526.            has been called.</li>
  1527. </ol>
  1528. <p>The <code>is_parameter_entity</code> argument will be non-zero for
  1529. a parameter entity and zero for a general entity.</p> <p>Note: skipped
  1530. parameter entities in declarations and skipped general entities in
  1531. attribute values cannot be reported, because the event would be out of
  1532. sync with the reporting of the declarations or attribute values</p>
  1533. </div>
  1534.  
  1535. <div class="handler">
  1536. <pre class="setter" id="XML_SetUnknownEncodingHandler">
  1537. void XMLCALL
  1538. XML_SetUnknownEncodingHandler(XML_Parser p,
  1539.                              XML_UnknownEncodingHandler enchandler,
  1540.                               void *encodingHandlerData)
  1541. </pre>
  1542. <pre class="signature">
  1543. typedef int
  1544. (XMLCALL *XML_UnknownEncodingHandler)(void *encodingHandlerData,
  1545.                                      const XML_Char *name,
  1546.                                      XML_Encoding *info);
  1547.  
  1548. typedef struct {
  1549.  int map[256];
  1550.  void *data;
  1551.  int (XMLCALL *convert)(void *data, const char *s);
  1552.  void (XMLCALL *release)(void *data);
  1553. } XML_Encoding;
  1554. </pre>
  1555. <p>Set a handler to deal with encodings other than the <a
  1556. href="#builtin_encodings">built in set</a>. This should be done before
  1557. <code><a href= "#XML_Parse" >XML_Parse</a></code> or <code><a href=
  1558. "#XML_ParseBuffer" >XML_ParseBuffer</a></code> have been called on the
  1559. given parser.</p> <p>If the handler knows how to deal with an encoding
  1560. with the given name, it should fill in the <code>info</code> data
  1561. structure and return <code>XML_STATUS_OK</code>. Otherwise it
  1562. should return <code>XML_STATUS_ERROR</code>. The handler will be called
  1563. at most once per parsed (external) entity. The optional application
  1564. data pointer <code>encodingHandlerData</code> will be passed back to
  1565. the handler.</p>
  1566.  
  1567. <p>The map array contains information for every possible possible leading
  1568. byte in a byte sequence. If the corresponding value is &gt;= 0, then it's
  1569. a single byte sequence and the byte encodes that Unicode value. If the
  1570. value is -1, then that byte is invalid as the initial byte in a sequence.
  1571. If the value is -n, where n is an integer &gt; 1, then n is the number of
  1572. bytes in the sequence and the actual conversion is accomplished by a
  1573. call to the function pointed at by convert. This function may return -1
  1574. if the sequence itself is invalid. The convert pointer may be null if
  1575. there are only single byte codes. The data parameter passed to the convert
  1576. function is the data pointer from <code>XML_Encoding</code>. The
  1577. string s is <em>NOT</em> nul-terminated and points at the sequence of
  1578. bytes to be converted.</p>
  1579.  
  1580. <p>The function pointed at by <code>release</code> is called by the
  1581. parser when it is finished with the encoding. It may be NULL.</p>
  1582. </div>
  1583.  
  1584. <div class="handler">
  1585. <pre class="setter" id="XML_SetStartNamespaceDeclHandler">
  1586. void XMLCALL
  1587. XML_SetStartNamespaceDeclHandler(XML_Parser p,
  1588.                                  XML_StartNamespaceDeclHandler start);
  1589. </pre>
  1590. <pre class="signature">
  1591. typedef void
  1592. (XMLCALL *XML_StartNamespaceDeclHandler)(void *userData,
  1593.                                          const XML_Char *prefix,
  1594.                                          const XML_Char *uri);
  1595. </pre>
  1596. <p>Set a handler to be called when a namespace is declared. Namespace
  1597. declarations occur inside start tags. But the namespace declaration start
  1598. handler is called before the start tag handler for each namespace declared
  1599. in that start tag.</p>
  1600. </div>
  1601.  
  1602. <div class="handler">
  1603. <pre class="setter" id="XML_SetEndNamespaceDeclHandler">
  1604. void XMLCALL
  1605. XML_SetEndNamespaceDeclHandler(XML_Parser p,
  1606.                                XML_EndNamespaceDeclHandler end);
  1607. </pre>
  1608. <pre class="signature">
  1609. typedef void
  1610. (XMLCALL *XML_EndNamespaceDeclHandler)(void *userData,
  1611.                                        const XML_Char *prefix);
  1612. </pre>
  1613. <p>Set a handler to be called when leaving the scope of a namespace
  1614. declaration. This will be called, for each namespace declaration,
  1615. after the handler for the end tag of the element in which the
  1616. namespace was declared.</p>
  1617. </div>
  1618.  
  1619. <div class="handler">
  1620. <pre class="setter" id="XML_SetNamespaceDeclHandler">
  1621. void XMLCALL
  1622. XML_SetNamespaceDeclHandler(XML_Parser p,
  1623.                             XML_StartNamespaceDeclHandler start,
  1624.                             XML_EndNamespaceDeclHandler end)
  1625. </pre>
  1626. <p>Sets both namespace declaration handlers with a single call.</p>
  1627. </div>
  1628.  
  1629. <div class="handler">
  1630. <pre class="setter" id="XML_SetXmlDeclHandler">
  1631. void XMLCALL
  1632. XML_SetXmlDeclHandler(XML_Parser p,
  1633.                       XML_XmlDeclHandler xmldecl);
  1634. </pre>
  1635. <pre class="signature">
  1636. typedef void
  1637. (XMLCALL *XML_XmlDeclHandler)(void            *userData,
  1638.                               const XML_Char  *version,
  1639.                               const XML_Char  *encoding,
  1640.                               int             standalone);
  1641. </pre>
  1642. <p>Sets a handler that is called for XML declarations and also for
  1643. text declarations discovered in external entities. The way to
  1644. distinguish is that the <code>version</code> parameter will be NULL
  1645. for text declarations. The <code>encoding</code> parameter may be NULL
  1646. for an XML declaration. The <code>standalone</code> argument will
  1647. contain -1, 0, or 1 indicating respectively that there was no
  1648. standalone parameter in the declaration, that it was given as no, or
  1649. that it was given as yes.</p>
  1650. </div>
  1651.  
  1652. <div class="handler">
  1653. <pre class="setter" id="XML_SetStartDoctypeDeclHandler">
  1654. void XMLCALL
  1655. XML_SetStartDoctypeDeclHandler(XML_Parser p,
  1656.                                XML_StartDoctypeDeclHandler start);
  1657. </pre>
  1658. <pre class="signature">
  1659. typedef void
  1660. (XMLCALL *XML_StartDoctypeDeclHandler)(void           *userData,
  1661.                                        const XML_Char *doctypeName,
  1662.                                        const XML_Char *sysid,
  1663.                                        const XML_Char *pubid,
  1664.                                        int            has_internal_subset);
  1665. </pre>
  1666. <p>Set a handler that is called at the start of a DOCTYPE declaration,
  1667. before any external or internal subset is parsed. Both <code>sysid</code>
  1668. and <code>pubid</code> may be NULL. The <code>has_internal_subset</code>
  1669. will be non-zero if the DOCTYPE declaration has an internal subset.</p>
  1670. </div>
  1671.  
  1672. <div class="handler">
  1673. <pre class="setter" id="XML_SetEndDoctypeDeclHandler">
  1674. void XMLCALL
  1675. XML_SetEndDoctypeDeclHandler(XML_Parser p,
  1676.                              XML_EndDoctypeDeclHandler end);
  1677. </pre>
  1678. <pre class="signature">
  1679. typedef void
  1680. (XMLCALL *XML_EndDoctypeDeclHandler)(void *userData);
  1681. </pre>
  1682. <p>Set a handler that is called at the end of a DOCTYPE declaration,
  1683. after parsing any external subset.</p>
  1684. </div>
  1685.  
  1686. <div class="handler">
  1687. <pre class="setter" id="XML_SetDoctypeDeclHandler">
  1688. void XMLCALL
  1689. XML_SetDoctypeDeclHandler(XML_Parser p,
  1690.                           XML_StartDoctypeDeclHandler start,
  1691.                           XML_EndDoctypeDeclHandler end);
  1692. </pre>
  1693. <p>Set both doctype handlers with one call.</p>
  1694. </div>
  1695.  
  1696. <div class="handler">
  1697. <pre class="setter" id="XML_SetElementDeclHandler">
  1698. void XMLCALL
  1699. XML_SetElementDeclHandler(XML_Parser p,
  1700.                           XML_ElementDeclHandler eldecl);
  1701. </pre>
  1702. <pre class="signature">
  1703. typedef void
  1704. (XMLCALL *XML_ElementDeclHandler)(void *userData,
  1705.                                   const XML_Char *name,
  1706.                                   XML_Content *model);
  1707. </pre>
  1708. <pre class="signature">
  1709. enum XML_Content_Type {
  1710.   XML_CTYPE_EMPTY = 1,
  1711.   XML_CTYPE_ANY,
  1712.   XML_CTYPE_MIXED,
  1713.   XML_CTYPE_NAME,
  1714.   XML_CTYPE_CHOICE,
  1715.   XML_CTYPE_SEQ
  1716. };
  1717.  
  1718. enum XML_Content_Quant {
  1719.   XML_CQUANT_NONE,
  1720.   XML_CQUANT_OPT,
  1721.   XML_CQUANT_REP,
  1722.   XML_CQUANT_PLUS
  1723. };
  1724.  
  1725. typedef struct XML_cp XML_Content;
  1726.  
  1727. struct XML_cp {
  1728.   enum XML_Content_Type         type;
  1729.   enum XML_Content_Quant        quant;
  1730.   const XML_Char *              name;
  1731.   unsigned int                  numchildren;
  1732.   XML_Content *                 children;
  1733. };
  1734. </pre>
  1735. <p>Sets a handler for element declarations in a DTD. The handler gets
  1736. called with the name of the element in the declaration and a pointer
  1737. to a structure that contains the element model. It is the
  1738. application's responsibility to free this data structure using
  1739. <code><a href="#XML_FreeContentModel"
  1740. >XML_FreeContentModel</a></code>.</p>
  1741.  
  1742. <p>The <code>model</code> argument is the root of a tree of
  1743. <code>XML_Content</code> nodes. If <code>type</code> equals
  1744. <code>XML_CTYPE_EMPTY</code> or <code>XML_CTYPE_ANY</code>, then
  1745. <code>quant</code> will be <code>XML_CQUANT_NONE</code>, and the other
  1746. fields will be zero or NULL.  If <code>type</code> is
  1747. <code>XML_CTYPE_MIXED</code>, then <code>quant</code> will be
  1748. <code>XML_CQUANT_NONE</code> or <code>XML_CQUANT_REP</code> and
  1749. <code>numchildren</code> will contain the number of elements that are
  1750. allowed to be mixed in and <code>children</code> points to an array of
  1751. <code>XML_Content</code> structures that will all have type
  1752. XML_CTYPE_NAME with no quantification.  Only the root node can be type
  1753. <code>XML_CTYPE_EMPTY</code>, <code>XML_CTYPE_ANY</code>, or
  1754. <code>XML_CTYPE_MIXED</code>.</p>
  1755.  
  1756. <p>For type <code>XML_CTYPE_NAME</code>, the <code>name</code> field
  1757. points to the name and the <code>numchildren</code> and
  1758. <code>children</code> fields will be zero and NULL. The
  1759. <code>quant</code> field will indicate any quantifiers placed on the
  1760. name.</p>
  1761.  
  1762. <p>Types <code>XML_CTYPE_CHOICE</code> and <code>XML_CTYPE_SEQ</code>
  1763. indicate a choice or sequence respectively. The
  1764. <code>numchildren</code> field indicates how many nodes in the choice
  1765. or sequence and <code>children</code> points to the nodes.</p>
  1766. </div>
  1767.  
  1768. <div class="handler">
  1769. <pre class="setter" id="XML_SetAttlistDeclHandler">
  1770. void XMLCALL
  1771. XML_SetAttlistDeclHandler(XML_Parser p,
  1772.                          XML_AttlistDeclHandler attdecl);
  1773. </pre>
  1774. <pre class="signature">
  1775. typedef void
  1776. (XMLCALL *XML_AttlistDeclHandler)(void           *userData,
  1777.                                  const XML_Char *elname,
  1778.                                  const XML_Char *attname,
  1779.                                  const XML_Char *att_type,
  1780.                                  const XML_Char *dflt,
  1781.                                  int            isrequired);
  1782. </pre>
  1783. <p>Set a handler for attlist declarations in the DTD. This handler is
  1784. called for <em>each</em> attribute. So a single attlist declaration
  1785. with multiple attributes declared will generate multiple calls to this
  1786. handler. The <code>elname</code> parameter returns the name of the
  1787. element for which the attribute is being declared. The attribute name
  1788. is in the <code>attname</code> parameter. The attribute type is in the
  1789. <code>att_type</code> parameter.  It is the string representing the
  1790. type in the declaration with whitespace removed.</p>
  1791.  
  1792. <p>The <code>dflt</code> parameter holds the default value. It will be
  1793. NULL in the case of "#IMPLIED" or "#REQUIRED" attributes. You can
  1794. distinguish these two cases by checking the <code>isrequired</code>
  1795. parameter, which will be true in the case of "#REQUIRED" attributes.
  1796. Attributes which are "#FIXED" will have also have a true
  1797. <code>isrequired</code>, but they will have the non-NULL fixed value
  1798. in the <code>dflt</code> parameter.</p>
  1799. </div>
  1800.  
  1801. <div class="handler">
  1802. <pre class="setter" id="XML_SetEntityDeclHandler">
  1803. void XMLCALL
  1804. XML_SetEntityDeclHandler(XML_Parser p,
  1805.                          XML_EntityDeclHandler handler);
  1806. </pre>
  1807. <pre class="signature">
  1808. typedef void
  1809. (XMLCALL *XML_EntityDeclHandler)(void           *userData,
  1810.                                 const XML_Char *entityName,
  1811.                                 int            is_parameter_entity,
  1812.                                 const XML_Char *value,
  1813.                                 int            value_length,
  1814.                                 const XML_Char *base,
  1815.                                 const XML_Char *systemId,
  1816.                                 const XML_Char *publicId,
  1817.                                 const XML_Char *notationName);
  1818. </pre>
  1819. <p>Sets a handler that will be called for all entity declarations.
  1820. The <code>is_parameter_entity</code> argument will be non-zero in the
  1821. case of parameter entities and zero otherwise.</p>
  1822.  
  1823. <p>For internal entities (<code>&lt;!ENTITY foo "bar"&gt;</code>),
  1824. <code>value</code> will be non-NULL and <code>systemId</code>,
  1825. <code>publicId</code>, and <code>notationName</code> will all be NULL.
  1826. The value string is <em>not</em> NULL terminated; the length is
  1827. provided in the <code>value_length</code> parameter. Do not use
  1828. <code>value_length</code> to test for internal entities, since it is
  1829. legal to have zero-length values. Instead check for whether or not
  1830. <code>value</code> is NULL.</p> <p>The <code>notationName</code>
  1831. argument will have a non-NULL value only for unparsed entity
  1832. declarations.</p>
  1833. </div>
  1834.  
  1835. <div class="handler">
  1836. <pre class="setter" id="XML_SetUnparsedEntityDeclHandler">
  1837. void XMLCALL
  1838. XML_SetUnparsedEntityDeclHandler(XML_Parser p,
  1839.                                 XML_UnparsedEntityDeclHandler h)
  1840. </pre>
  1841. <pre class="signature">
  1842. typedef void
  1843. (XMLCALL *XML_UnparsedEntityDeclHandler)(void *userData,
  1844.                                         const XML_Char *entityName,
  1845.                                         const XML_Char *base,
  1846.                                         const XML_Char *systemId,
  1847.                                         const XML_Char *publicId,
  1848.                                         const XML_Char *notationName);
  1849. </pre>
  1850. <p>Set a handler that receives declarations of unparsed entities. These
  1851. are entity declarations that have a notation (NDATA) field:</p>
  1852.  
  1853. <div id="eg"><pre>
  1854. &lt;!ENTITY logo SYSTEM "images/logo.gif" NDATA gif&gt;
  1855. </pre></div>
  1856. <p>This handler is obsolete and is provided for backwards
  1857. compatibility.  Use instead <a href= "#XML_SetEntityDeclHandler"
  1858. >XML_SetEntityDeclHandler</a>.</p>
  1859. </div>
  1860.  
  1861. <div class="handler">
  1862. <pre class="setter" id="XML_SetNotationDeclHandler">
  1863. void XMLCALL
  1864. XML_SetNotationDeclHandler(XML_Parser p,
  1865.                           XML_NotationDeclHandler h)
  1866. </pre>
  1867. <pre class="signature">
  1868. typedef void
  1869. (XMLCALL *XML_NotationDeclHandler)(void *userData,
  1870.                                   const XML_Char *notationName,
  1871.                                   const XML_Char *base,
  1872.                                   const XML_Char *systemId,
  1873.                                   const XML_Char *publicId);
  1874. </pre>
  1875. <p>Set a handler that receives notation declarations.</p>
  1876. </div>
  1877.  
  1878. <div class="handler">
  1879. <pre class="setter" id="XML_SetNotStandaloneHandler">
  1880. void XMLCALL
  1881. XML_SetNotStandaloneHandler(XML_Parser p,
  1882.                            XML_NotStandaloneHandler h)
  1883. </pre>
  1884. <pre class="signature">
  1885. typedef int
  1886. (XMLCALL *XML_NotStandaloneHandler)(void *userData);
  1887. </pre>
  1888. <p>Set a handler that is called if the document is not "standalone".
  1889. This happens when there is an external subset or a reference to a
  1890. parameter entity, but does not have standalone set to "yes" in an XML
  1891. declaration.  If this handler returns <code>XML_STATUS_ERROR</code>,
  1892. then the parser will throw an <code>XML_ERROR_NOT_STANDALONE</code>
  1893. error.</p>
  1894. </div>
  1895.  
  1896. <h3><a name="position">Parse position and error reporting functions</a></h3>
  1897.  
  1898. <p>These are the functions you'll want to call when the parse
  1899. functions return <code>XML_STATUS_ERROR</code> (a parse error has
  1900. occurred), although the position reporting functions are useful outside
  1901. of errors. The position reported is the byte position (in the original
  1902. document or entity encoding) of the first of the sequence of
  1903. characters that generated the current event (or the error that caused
  1904. the parse functions to return <code>XML_STATUS_ERROR</code>.)  The
  1905. exceptions are callbacks trigged by declarations in the document
  1906. prologue, in which case they exact position reported is somewhere in the
  1907. relevant markup, but not necessarily as meaningful as for other
  1908. events.</p>
  1909.  
  1910. <p>The position reporting functions are accurate only outside of the
  1911. DTD.  In other words, they usually return bogus information when
  1912. called from within a DTD declaration handler.</p>
  1913.  
  1914. <pre class="fcndec" id="XML_GetErrorCode">
  1915. enum XML_Error XMLCALL
  1916. XML_GetErrorCode(XML_Parser p);
  1917. </pre>
  1918. <div class="fcndef">
  1919. Return what type of error has occurred.
  1920. </div>
  1921.  
  1922. <pre class="fcndec" id="XML_ErrorString">
  1923. const XML_LChar * XMLCALL
  1924. XML_ErrorString(enum XML_Error code);
  1925. </pre>
  1926. <div class="fcndef">
  1927. Return a string describing the error corresponding to code.
  1928. The code should be one of the enums that can be returned from
  1929. <code><a href= "#XML_GetErrorCode" >XML_GetErrorCode</a></code>.
  1930. </div>
  1931.  
  1932. <pre class="fcndec" id="XML_GetCurrentByteIndex">
  1933. XML_Index XMLCALL
  1934. XML_GetCurrentByteIndex(XML_Parser p);
  1935. </pre>
  1936. <div class="fcndef">
  1937. Return the byte offset of the position.  This always corresponds to
  1938. the values returned by <code><a href= "#XML_GetCurrentLineNumber"
  1939. >XML_GetCurrentLineNumber</a></code> and <code><a href=
  1940. "#XML_GetCurrentColumnNumber" >XML_GetCurrentColumnNumber</a></code>.
  1941. </div>
  1942.  
  1943. <pre class="fcndec" id="XML_GetCurrentLineNumber">
  1944. XML_Size XMLCALL
  1945. XML_GetCurrentLineNumber(XML_Parser p);
  1946. </pre>
  1947. <div class="fcndef">
  1948. Return the line number of the position.  The first line is reported as
  1949. <code>1</code>.
  1950. </div>
  1951.  
  1952. <pre class="fcndec" id="XML_GetCurrentColumnNumber">
  1953. XML_Size XMLCALL
  1954. XML_GetCurrentColumnNumber(XML_Parser p);
  1955. </pre>
  1956. <div class="fcndef">
  1957. Return the offset, from the beginning of the current line, of
  1958. the position.
  1959. </div>
  1960.  
  1961. <pre class="fcndec" id="XML_GetCurrentByteCount">
  1962. int XMLCALL
  1963. XML_GetCurrentByteCount(XML_Parser p);
  1964. </pre>
  1965. <div class="fcndef">
  1966. Return the number of bytes in the current event. Returns
  1967. <code>0</code> if the event is inside a reference to an internal
  1968. entity and for the end-tag event for empty element tags (the later can
  1969. be used to distinguish empty-element tags from empty elements using
  1970. separate start and end tags).
  1971. </div>
  1972.  
  1973. <pre class="fcndec" id="XML_GetInputContext">
  1974. const char * XMLCALL
  1975. XML_GetInputContext(XML_Parser p,
  1976.                     int *offset,
  1977.                     int *size);
  1978. </pre>
  1979. <div class="fcndef">
  1980.  
  1981. <p>Returns the parser's input buffer, sets the integer pointed at by
  1982. <code>offset</code> to the offset within this buffer of the current
  1983. parse position, and set the integer pointed at by <code>size</code> to
  1984. the size of the returned buffer.</p>
  1985.  
  1986. <p>This should only be called from within a handler during an active
  1987. parse and the returned buffer should only be referred to from within
  1988. the handler that made the call. This input buffer contains the
  1989. untranslated bytes of the input.</p>
  1990.  
  1991. <p>Only a limited amount of context is kept, so if the event
  1992. triggering a call spans over a very large amount of input, the actual
  1993. parse position may be before the beginning of the buffer.</p>
  1994.  
  1995. <p>If <code>XML_CONTEXT_BYTES</code> is not defined, this will always
  1996. return NULL.</p>
  1997. </div>
  1998.  
  1999. <h3><a name="miscellaneous">Miscellaneous functions</a></h3>
  2000.  
  2001. <p>The functions in this section either obtain state information from
  2002. the parser or can be used to dynamicly set parser options.</p>
  2003.  
  2004. <pre class="fcndec" id="XML_SetUserData">
  2005. void XMLCALL
  2006. XML_SetUserData(XML_Parser p,
  2007.                void *userData);
  2008. </pre>
  2009. <div class="fcndef">
  2010. This sets the user data pointer that gets passed to handlers.  It
  2011. overwrites any previous value for this pointer. Note that the
  2012. application is responsible for freeing the memory associated with
  2013. <code>userData</code> when it is finished with the parser. So if you
  2014. call this when there's already a pointer there, and you haven't freed
  2015. the memory associated with it, then you've probably just leaked
  2016. memory.
  2017. </div>
  2018.  
  2019. <pre class="fcndec" id="XML_GetUserData">
  2020. void * XMLCALL
  2021. XML_GetUserData(XML_Parser p);
  2022. </pre>
  2023. <div class="fcndef">
  2024. This returns the user data pointer that gets passed to handlers.
  2025. It is actually implemented as a macro.
  2026. </div>
  2027.  
  2028. <pre class="fcndec" id="XML_UseParserAsHandlerArg">
  2029. void XMLCALL
  2030. XML_UseParserAsHandlerArg(XML_Parser p);
  2031. </pre>
  2032. <div class="fcndef">
  2033. After this is called, handlers receive the parser in their
  2034. <code>userData</code> arguments.  The user data can still be obtained
  2035. using the <code><a href= "#XML_GetUserData"
  2036. >XML_GetUserData</a></code> function.
  2037. </div>
  2038.  
  2039. <pre class="fcndec" id="XML_SetBase">
  2040. enum XML_Status XMLCALL
  2041. XML_SetBase(XML_Parser p,
  2042.             const XML_Char *base);
  2043. </pre>
  2044. <div class="fcndef">
  2045. Set the base to be used for resolving relative URIs in system
  2046. identifiers.  The return value is <code>XML_STATUS_ERROR</code> if
  2047. there's no memory to store base, otherwise it's
  2048. <code>XML_STATUS_OK</code>.
  2049. </div>
  2050.  
  2051. <pre class="fcndec" id="XML_GetBase">
  2052. const XML_Char * XMLCALL
  2053. XML_GetBase(XML_Parser p);
  2054. </pre>
  2055. <div class="fcndef">
  2056. Return the base for resolving relative URIs.
  2057. </div>
  2058.  
  2059. <pre class="fcndec" id="XML_GetSpecifiedAttributeCount">
  2060. int XMLCALL
  2061. XML_GetSpecifiedAttributeCount(XML_Parser p);
  2062. </pre>
  2063. <div class="fcndef">
  2064. When attributes are reported to the start handler in the atts vector,
  2065. attributes that were explicitly set in the element occur before any
  2066. attributes that receive their value from default information in an
  2067. ATTLIST declaration. This function returns the number of attributes
  2068. that were explicitly set times two, thus giving the offset in the
  2069. <code>atts</code> array passed to the start tag handler of the first
  2070. attribute set due to defaults. It supplies information for the last
  2071. call to a start handler. If called inside a start handler, then that
  2072. means the current call.
  2073. </div>
  2074.  
  2075. <pre class="fcndec" id="XML_GetIdAttributeIndex">
  2076. int XMLCALL
  2077. XML_GetIdAttributeIndex(XML_Parser p);
  2078. </pre>
  2079. <div class="fcndef">
  2080. Returns the index of the ID attribute passed in the atts array in the
  2081. last call to <code><a href= "#XML_StartElementHandler"
  2082. >XML_StartElementHandler</a></code>, or -1 if there is no ID
  2083. attribute. If called inside a start handler, then that means the
  2084. current call.
  2085. </div>
  2086.  
  2087. <pre class="fcndec" id="XML_GetAttributeInfo">
  2088. const XML_AttrInfo * XMLCALL
  2089. XML_GetAttributeInfo(XML_Parser parser);
  2090. </pre>
  2091. <pre class="signature">
  2092. typedef struct {
  2093.   XML_Index  nameStart;  /* Offset to beginning of the attribute name. */
  2094.   XML_Index  nameEnd;    /* Offset after the attribute name's last byte. */
  2095.  XML_Index  valueStart; /* Offset to beginning of the attribute value. */
  2096.  XML_Index  valueEnd;   /* Offset after the attribute value's last byte. */
  2097. } XML_AttrInfo;
  2098. </pre>
  2099. <div class="fcndef">
  2100. Returns an array of <code>XML_AttrInfo</code> structures for the
  2101. attribute/value pairs passed in the last call to the
  2102. <code>XML_StartElementHandler</code> that were specified
  2103. in the start-tag rather than defaulted. Each attribute/value pair counts
  2104. as 1; thus the number of entries in the array is
  2105. <code>XML_GetSpecifiedAttributeCount(parser) / 2</code>.
  2106. </div>
  2107.  
  2108. <pre class="fcndec" id="XML_SetEncoding">
  2109. enum XML_Status XMLCALL
  2110. XML_SetEncoding(XML_Parser p,
  2111.                 const XML_Char *encoding);
  2112. </pre>
  2113. <div class="fcndef">
  2114. Set the encoding to be used by the parser. It is equivalent to
  2115. passing a non-null encoding argument to the parser creation functions.
  2116. It must not be called after <code><a href= "#XML_Parse"
  2117. >XML_Parse</a></code> or <code><a href= "#XML_ParseBuffer"
  2118. >XML_ParseBuffer</a></code> have been called on the given parser.
  2119. Returns <code>XML_STATUS_OK</code> on success or
  2120. <code>XML_STATUS_ERROR</code> on error.
  2121. </div>
  2122.  
  2123. <pre class="fcndec" id="XML_SetParamEntityParsing">
  2124. int XMLCALL
  2125. XML_SetParamEntityParsing(XML_Parser p,
  2126.                           enum XML_ParamEntityParsing code);
  2127. </pre>
  2128. <div class="fcndef">
  2129. This enables parsing of parameter entities, including the external
  2130. parameter entity that is the external DTD subset, according to
  2131. <code>code</code>.
  2132. The choices for <code>code</code> are:
  2133. <ul>
  2134. <li><code>XML_PARAM_ENTITY_PARSING_NEVER</code></li>
  2135. <li><code>XML_PARAM_ENTITY_PARSING_UNLESS_STANDALONE</code></li>
  2136. <li><code>XML_PARAM_ENTITY_PARSING_ALWAYS</code></li>
  2137. </ul>
  2138. <b>Note:</b> If <code>XML_SetParamEntityParsing</code> is called after
  2139. <code>XML_Parse</code> or <code>XML_ParseBuffer</code>, then it has
  2140. no effect and will always return 0.
  2141. </div>
  2142.  
  2143. <pre class="fcndec" id="XML_SetHashSalt">
  2144. int XMLCALL
  2145. XML_SetHashSalt(XML_Parser p,
  2146.                 unsigned long hash_salt);
  2147. </pre>
  2148. <div class="fcndef">
  2149. Sets the hash salt to use for internal hash calculations.
  2150. Helps in preventing DoS attacks based on predicting hash
  2151. function behavior. In order to have an effect this must be called
  2152. before parsing has started. Returns 1 if successful, 0 when called
  2153. after <code>XML_Parse</code> or <code>XML_ParseBuffer</code>.
  2154. <p><b>Note:</b> This call is optional, as the parser will auto-generate a new
  2155. random salt value if no value has been set at the start of parsing.</p>
  2156. </div>
  2157.  
  2158. <pre class="fcndec" id="XML_UseForeignDTD">
  2159. enum XML_Error XMLCALL
  2160. XML_UseForeignDTD(XML_Parser parser, XML_Bool useDTD);
  2161. </pre>
  2162. <div class="fcndef">
  2163. <p>This function allows an application to provide an external subset
  2164. for the document type declaration for documents which do not specify
  2165. an external subset of their own.  For documents which specify an
  2166. external subset in their DOCTYPE declaration, the application-provided
  2167. subset will be ignored.  If the document does not contain a DOCTYPE
  2168. declaration at all and <code>useDTD</code> is true, the
  2169. application-provided subset will be parsed, but the
  2170. <code>startDoctypeDeclHandler</code> and
  2171. <code>endDoctypeDeclHandler</code> functions, if set, will not be
  2172. called.  The setting of parameter entity parsing, controlled using
  2173. <code><a href= "#XML_SetParamEntityParsing"
  2174. >XML_SetParamEntityParsing</a></code>, will be honored.</p>
  2175.  
  2176. <p>The application-provided external subset is read by calling the
  2177. external entity reference handler set via <code><a href=
  2178. "#XML_SetExternalEntityRefHandler"
  2179. >XML_SetExternalEntityRefHandler</a></code> with both
  2180. <code>publicId</code> and <code>systemId</code> set to NULL.</p>
  2181.  
  2182. <p>If this function is called after parsing has begun, it returns
  2183. <code>XML_ERROR_CANT_CHANGE_FEATURE_ONCE_PARSING</code> and ignores
  2184. <code>useDTD</code>.  If called when Expat has been compiled without
  2185. DTD support, it returns
  2186. <code>XML_ERROR_FEATURE_REQUIRES_XML_DTD</code>.  Otherwise, it
  2187. returns <code>XML_ERROR_NONE</code>.</p>
  2188.  
  2189. <p><b>Note:</b> For the purpose of checking WFC: Entity Declared, passing
  2190. <code>useDTD == XML_TRUE</code> will make the parser behave as if
  2191. the document had a DTD with an external subset. This holds true even if
  2192. the external entity reference handler returns without action.</p>
  2193. </div>
  2194.  
  2195. <pre class="fcndec" id="XML_SetReturnNSTriplet">
  2196. void XMLCALL
  2197. XML_SetReturnNSTriplet(XML_Parser parser,
  2198.                        int        do_nst);
  2199. </pre>
  2200. <div class="fcndef">
  2201. <p>
  2202. This function only has an effect when using a parser created with
  2203. <code><a href= "#XML_ParserCreateNS" >XML_ParserCreateNS</a></code>,
  2204. i.e. when namespace processing is in effect. The <code>do_nst</code>
  2205. sets whether or not prefixes are returned with names qualified with a
  2206. namespace prefix. If this function is called with <code>do_nst</code>
  2207. non-zero, then afterwards namespace qualified names (that is qualified
  2208. with a prefix as opposed to belonging to a default namespace) are
  2209. returned as a triplet with the three parts separated by the namespace
  2210. separator specified when the parser was created.  The order of
  2211. returned parts is URI, local name, and prefix.</p> <p>If
  2212. <code>do_nst</code> is zero, then namespaces are reported in the
  2213. default manner, URI then local_name separated by the namespace
  2214. separator.</p>
  2215. </div>
  2216.  
  2217. <pre class="fcndec" id="XML_DefaultCurrent">
  2218. void XMLCALL
  2219. XML_DefaultCurrent(XML_Parser parser);
  2220. </pre>
  2221. <div class="fcndef">
  2222. This can be called within a handler for a start element, end element,
  2223. processing instruction or character data.  It causes the corresponding
  2224. markup to be passed to the default handler set by <code><a
  2225. href="#XML_SetDefaultHandler" >XML_SetDefaultHandler</a></code> or
  2226. <code><a href="#XML_SetDefaultHandlerExpand"
  2227. >XML_SetDefaultHandlerExpand</a></code>.  It does nothing if there is
  2228. not a default handler.
  2229. </div>
  2230.  
  2231. <pre class="fcndec" id="XML_ExpatVersion">
  2232. XML_LChar * XMLCALL
  2233. XML_ExpatVersion();
  2234. </pre>
  2235. <div class="fcndef">
  2236. Return the library version as a string (e.g. <code>"expat_1.95.1"</code>).
  2237. </div>
  2238.  
  2239. <pre class="fcndec" id="XML_ExpatVersionInfo">
  2240. struct XML_Expat_Version XMLCALL
  2241. XML_ExpatVersionInfo();
  2242. </pre>
  2243. <pre class="signature">
  2244. typedef struct {
  2245.   int major;
  2246.   int minor;
  2247.   int micro;
  2248. } XML_Expat_Version;
  2249. </pre>
  2250. <div class="fcndef">
  2251. Return the library version information as a structure.
  2252. Some macros are also defined that support compile-time tests of the
  2253. library version:
  2254. <ul>
  2255. <li><code>XML_MAJOR_VERSION</code></li>
  2256. <li><code>XML_MINOR_VERSION</code></li>
  2257. <li><code>XML_MICRO_VERSION</code></li>
  2258. </ul>
  2259. Testing these constants is currently the best way to determine if
  2260. particular parts of the Expat API are available.
  2261. </div>
  2262.  
  2263. <pre class="fcndec" id="XML_GetFeatureList">
  2264. const XML_Feature * XMLCALL
  2265. XML_GetFeatureList();
  2266. </pre>
  2267. <pre class="signature">
  2268. enum XML_FeatureEnum {
  2269.   XML_FEATURE_END = 0,
  2270.   XML_FEATURE_UNICODE,
  2271.   XML_FEATURE_UNICODE_WCHAR_T,
  2272.   XML_FEATURE_DTD,
  2273.   XML_FEATURE_CONTEXT_BYTES,
  2274.   XML_FEATURE_MIN_SIZE,
  2275.   XML_FEATURE_SIZEOF_XML_CHAR,
  2276.   XML_FEATURE_SIZEOF_XML_LCHAR,
  2277.   XML_FEATURE_NS,
  2278.   XML_FEATURE_LARGE_SIZE
  2279. };
  2280.  
  2281. typedef struct {
  2282.   enum XML_FeatureEnum  feature;
  2283.   XML_LChar            *name;
  2284.   long int              value;
  2285. } XML_Feature;
  2286. </pre>
  2287. <div class="fcndef">
  2288. <p>Returns a list of "feature" records, providing details on how
  2289. Expat was configured at compile time.  Most applications should not
  2290. need to worry about this, but this information is otherwise not
  2291. available from Expat.  This function allows code that does need to
  2292. check these features to do so at runtime.</p>
  2293.  
  2294. <p>The return value is an array of <code>XML_Feature</code>,
  2295. terminated by a record with a <code>feature</code> of
  2296. <code>XML_FEATURE_END</code> and <code>name</code> of NULL,
  2297. identifying the feature-test macros Expat was compiled with.  Since an
  2298. application that requires this kind of information needs to determine
  2299. the type of character the <code>name</code> points to, records for the
  2300. <code>XML_FEATURE_SIZEOF_XML_CHAR</code> and
  2301. <code>XML_FEATURE_SIZEOF_XML_LCHAR</code> will be located at the
  2302. beginning of the list, followed by <code>XML_FEATURE_UNICODE</code>
  2303. and <code>XML_FEATURE_UNICODE_WCHAR_T</code>, if they are present at
  2304. all.</p>
  2305.  
  2306. <p>Some features have an associated value.  If there isn't an
  2307. associated value, the <code>value</code> field is set to 0.  At this
  2308. time, the following features have been defined to have values:</p>
  2309.  
  2310. <dl>
  2311.  <dt><code>XML_FEATURE_SIZEOF_XML_CHAR</code></dt>
  2312.  <dd>The number of bytes occupied by one <code>XML_Char</code>
  2313.  character.</dd>
  2314.  <dt><code>XML_FEATURE_SIZEOF_XML_LCHAR</code></dt>
  2315.  <dd>The number of bytes occupied by one <code>XML_LChar</code>
  2316.  character.</dd>
  2317.  <dt><code>XML_FEATURE_CONTEXT_BYTES</code></dt>
  2318.  <dd>The maximum number of characters of context which can be
  2319.  reported by <code><a href= "#XML_GetInputContext"
  2320.  >XML_GetInputContext</a></code>.</dd>
  2321. </dl>
  2322. </div>
  2323.  
  2324. <pre class="fcndec" id="XML_FreeContentModel">
  2325. void XMLCALL
  2326. XML_FreeContentModel(XML_Parser parser, XML_Content *model);
  2327. </pre>
  2328. <div class="fcndef">
  2329. Function to deallocate the <code>model</code> argument passed to the
  2330. <code>XML_ElementDeclHandler</code> callback set using <code><a
  2331. href="#XML_SetElementDeclHandler" >XML_ElementDeclHandler</a></code>.
  2332. This function should not be used for any other purpose.
  2333. </div>
  2334.  
  2335. <p>The following functions allow external code to share the memory
  2336. allocator an <code>XML_Parser</code> has been configured to use.  This
  2337. is especially useful for third-party libraries that interact with a
  2338. parser object created by application code, or heavily layered
  2339. applications.  This can be essential when using dynamically loaded
  2340. libraries which use different C standard libraries (this can happen on
  2341. Windows, at least).</p>
  2342.  
  2343. <pre class="fcndec" id="XML_MemMalloc">
  2344. void * XMLCALL
  2345. XML_MemMalloc(XML_Parser parser, size_t size);
  2346. </pre>
  2347. <div class="fcndef">
  2348. Allocate <code>size</code> bytes of memory using the allocator the
  2349. <code>parser</code> object has been configured to use.  Returns a
  2350. pointer to the memory or NULL on failure.  Memory allocated in this
  2351. way must be freed using <code><a href="#XML_MemFree"
  2352. >XML_MemFree</a></code>.
  2353. </div>
  2354.  
  2355. <pre class="fcndec" id="XML_MemRealloc">
  2356. void * XMLCALL
  2357. XML_MemRealloc(XML_Parser parser, void *ptr, size_t size);
  2358. </pre>
  2359. <div class="fcndef">
  2360. Allocate <code>size</code> bytes of memory using the allocator the
  2361. <code>parser</code> object has been configured to use.
  2362. <code>ptr</code> must point to a block of memory allocated by <code><a
  2363. href="#XML_MemMalloc" >XML_MemMalloc</a></code> or
  2364. <code>XML_MemRealloc</code>, or be NULL.  This function tries to
  2365. expand the block pointed to by <code>ptr</code> if possible.  Returns
  2366. a pointer to the memory or NULL on failure.  On success, the original
  2367. block has either been expanded or freed.  On failure, the original
  2368. block has not been freed; the caller is responsible for freeing the
  2369. original block.  Memory allocated in this way must be freed using
  2370. <code><a href="#XML_MemFree"
  2371. >XML_MemFree</a></code>.
  2372. </div>
  2373.  
  2374. <pre class="fcndec" id="XML_MemFree">
  2375. void XMLCALL
  2376. XML_MemFree(XML_Parser parser, void *ptr);
  2377. </pre>
  2378. <div class="fcndef">
  2379. Free a block of memory pointed to by <code>ptr</code>.  The block must
  2380. have been allocated by <code><a href="#XML_MemMalloc"
  2381. >XML_MemMalloc</a></code> or <code>XML_MemRealloc</code>, or be NULL.
  2382. </div>
  2383.  
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