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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
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10: <title>Expat XML Parser</title>
11: <meta name="author" content="Clark Cooper, coopercc@netheaven.com" />
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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_SetEncoding">XML_SetEncoding</a></li>
133: <li><a href="#XML_SetParamEntityParsing">XML_SetParamEntityParsing</a></li>
134: <li><a href="#XML_UseForeignDTD">XML_UseForeignDTD</a></li>
135: <li><a href="#XML_SetReturnNSTriplet">XML_SetReturnNSTriplet</a></li>
136: <li><a href="#XML_DefaultCurrent">XML_DefaultCurrent</a></li>
137: <li><a href="#XML_ExpatVersion">XML_ExpatVersion</a></li>
138: <li><a href="#XML_ExpatVersionInfo">XML_ExpatVersionInfo</a></li>
139: <li><a href="#XML_GetFeatureList">XML_GetFeatureList</a></li>
140: <li><a href="#XML_FreeContentModel">XML_FreeContentModel</a></li>
141: <li><a href="#XML_MemMalloc">XML_MemMalloc</a></li>
142: <li><a href="#XML_MemRealloc">XML_MemRealloc</a></li>
143: <li><a href="#XML_MemFree">XML_MemFree</a></li>
144: </ul>
145: </li>
146: </ul>
147: </li>
148: </ul>
149:
150: <hr />
151: <h2><a name="overview">Overview</a></h2>
152:
153: <p>Expat is a stream-oriented parser. You register callback (or
154: handler) functions with the parser and then start feeding it the
155: document. As the parser recognizes parts of the document, it will
156: call the appropriate handler for that part (if you've registered one.)
157: The document is fed to the parser in pieces, so you can start parsing
158: before you have all the document. This also allows you to parse really
159: huge documents that won't fit into memory.</p>
160:
161: <p>Expat can be intimidating due to the many kinds of handlers and
162: options you can set. But you only need to learn four functions in
163: order to do 90% of what you'll want to do with it:</p>
164:
165: <dl>
166:
167: <dt><code><a href= "#XML_ParserCreate"
168: >XML_ParserCreate</a></code></dt>
169: <dd>Create a new parser object.</dd>
170:
171: <dt><code><a href= "#XML_SetElementHandler"
172: >XML_SetElementHandler</a></code></dt>
173: <dd>Set handlers for start and end tags.</dd>
174:
175: <dt><code><a href= "#XML_SetCharacterDataHandler"
176: >XML_SetCharacterDataHandler</a></code></dt>
177: <dd>Set handler for text.</dd>
178:
179: <dt><code><a href= "#XML_Parse"
180: >XML_Parse</a></code></dt>
181: <dd>Pass a buffer full of document to the parser</dd>
182: </dl>
183:
184: <p>These functions and others are described in the <a
185: href="#reference">reference</a> part of this document. The reference
186: section also describes in detail the parameters passed to the
187: different types of handlers.</p>
188:
189: <p>Let's look at a very simple example program that only uses 3 of the
190: above functions (it doesn't need to set a character handler.) The
191: program <a href="../examples/outline.c">outline.c</a> prints an
192: element outline, indenting child elements to distinguish them from the
193: parent element that contains them. The start handler does all the
194: work. It prints two indenting spaces for every level of ancestor
195: elements, then it prints the element and attribute
196: information. Finally it increments the global <code>Depth</code>
197: variable.</p>
198:
199: <pre class="eg">
200: int Depth;
201:
202: void XMLCALL
203: start(void *data, const char *el, const char **attr) {
204: int i;
205:
206: for (i = 0; i < Depth; i++)
207: printf(" ");
208:
209: printf("%s", el);
210:
211: for (i = 0; attr[i]; i += 2) {
212: printf(" %s='%s'", attr[i], attr[i + 1]);
213: }
214:
215: printf("\n");
216: Depth++;
217: } /* End of start handler */
218: </pre>
219:
220: <p>The end tag simply does the bookkeeping work of decrementing
221: <code>Depth</code>.</p>
222: <pre class="eg">
223: void XMLCALL
224: end(void *data, const char *el) {
225: Depth--;
226: } /* End of end handler */
227: </pre>
228:
229: <p>Note the <code>XMLCALL</code> annotation used for the callbacks.
230: This is used to ensure that the Expat and the callbacks are using the
231: same calling convention in case the compiler options used for Expat
232: itself and the client code are different. Expat tries not to care
233: what the default calling convention is, though it may require that it
234: be compiled with a default convention of "cdecl" on some platforms.
235: For code which uses Expat, however, the calling convention is
236: specified by the <code>XMLCALL</code> annotation on most platforms;
237: callbacks should be defined using this annotation.</p>
238:
239: <p>The <code>XMLCALL</code> annotation was added in Expat 1.95.7, but
240: existing working Expat applications don't need to add it (since they
241: are already using the "cdecl" calling convention, or they wouldn't be
242: working). The annotation is only needed if the default calling
243: convention may be something other than "cdecl". To use the annotation
244: safely with older versions of Expat, you can conditionally define it
245: <em>after</em> including Expat's header file:</p>
246:
247: <pre class="eg">
248: #include <expat.h>
249:
250: #ifndef XMLCALL
251: #if defined(_MSC_EXTENSIONS) && !defined(__BEOS__) && !defined(__CYGWIN__)
252: #define XMLCALL __cdecl
253: #elif defined(__GNUC__)
254: #define XMLCALL __attribute__((cdecl))
255: #else
256: #define XMLCALL
257: #endif
258: #endif
259: </pre>
260:
261: <p>After creating the parser, the main program just has the job of
262: shoveling the document to the parser so that it can do its work.</p>
263:
264: <hr />
265: <h2><a name="building">Building and Installing Expat</a></h2>
266:
267: <p>The Expat distribution comes as a compressed (with GNU gzip) tar
268: file. You may download the latest version from <a href=
269: "http://sourceforge.net/projects/expat/" >Source Forge</a>. After
270: unpacking this, cd into the directory. Then follow either the Win32
271: directions or Unix directions below.</p>
272:
273: <h3>Building under Win32</h3>
274:
275: <p>If you're using the GNU compiler under cygwin, follow the Unix
276: directions in the next section. Otherwise if you have Microsoft's
277: Developer Studio installed, then from Windows Explorer double-click on
278: "expat.dsp" in the lib directory and build and install in the usual
279: manner.</p>
280:
281: <p>Alternatively, you may download the Win32 binary package that
282: contains the "expat.h" include file and a pre-built DLL.</p>
283:
284: <h3>Building under Unix (or GNU)</h3>
285:
286: <p>First you'll need to run the configure shell script in order to
287: configure the Makefiles and headers for your system.</p>
288:
289: <p>If you're happy with all the defaults that configure picks for you,
290: and you have permission on your system to install into /usr/local, you
291: can install Expat with this sequence of commands:</p>
292:
293: <pre class="eg">
294: ./configure
295: make
296: make install
297: </pre>
298:
299: <p>There are some options that you can provide to this script, but the
300: only one we'll mention here is the <code>--prefix</code> option. You
301: can find out all the options available by running configure with just
302: the <code>--help</code> option.</p>
303:
304: <p>By default, the configure script sets things up so that the library
305: gets installed in <code>/usr/local/lib</code> and the associated
306: header file in <code>/usr/local/include</code>. But if you were to
307: give the option, <code>--prefix=/home/me/mystuff</code>, then the
308: library and header would get installed in
309: <code>/home/me/mystuff/lib</code> and
310: <code>/home/me/mystuff/include</code> respectively.</p>
311:
312: <h3>Configuring Expat Using the Pre-Processor</h3>
313:
314: <p>Expat's feature set can be configured using a small number of
315: pre-processor definitions. The definition of this symbols does not
316: affect the set of entry points for Expat, only the behavior of the API
317: and the definition of character types in the case of
318: <code>XML_UNICODE_WCHAR_T</code>. The symbols are:</p>
319:
320: <dl class="cpp-symbols">
321: <dt>XML_DTD</dt>
322: <dd>Include support for using and reporting DTD-based content. If
323: this is defined, default attribute values from an external DTD subset
324: are reported and attribute value normalization occurs based on the
325: type of attributes defined in the external subset. Without
326: this, Expat has a smaller memory footprint and can be faster, but will
327: not load external entities or process conditional sections. This does
328: not affect the set of functions available in the API.</dd>
329:
330: <dt>XML_NS</dt>
331: <dd>When defined, support for the <cite><a href=
332: "http://www.w3.org/TR/REC-xml-names/" >Namespaces in XML</a></cite>
333: specification is included.</dd>
334:
335: <dt>XML_UNICODE</dt>
336: <dd>When defined, character data reported to the application is
337: encoded in UTF-16 using wide characters of the type
338: <code>XML_Char</code>. This is implied if
339: <code>XML_UNICODE_WCHAR_T</code> is defined.</dd>
340:
341: <dt>XML_UNICODE_WCHAR_T</dt>
342: <dd>If defined, causes the <code>XML_Char</code> character type to be
343: defined using the <code>wchar_t</code> type; otherwise, <code>unsigned
344: short</code> is used. Defining this implies
345: <code>XML_UNICODE</code>.</dd>
346:
347: <dt>XML_LARGE_SIZE</dt>
348: <dd>If defined, causes the <code>XML_Size</code> and <code>XML_Index</code>
349: integer types to be at least 64 bits in size. This is intended to support
350: processing of very large input streams, where the return values of
351: <code><a href="#XML_GetCurrentByteIndex" >XML_GetCurrentByteIndex</a></code>,
352: <code><a href="#XML_GetCurrentLineNumber" >XML_GetCurrentLineNumber</a></code> and
353: <code><a href="#XML_GetCurrentColumnNumber" >XML_GetCurrentColumnNumber</a></code>
354: could overflow. It may not be supported by all compilers, and is turned
355: off by default.</dd>
356:
357: <dt>XML_CONTEXT_BYTES</dt>
358: <dd>The number of input bytes of markup context which the parser will
359: ensure are available for reporting via <code><a href=
360: "#XML_GetInputContext" >XML_GetInputContext</a></code>. This is
361: normally set to 1024, and must be set to a positive interger. If this
362: is not defined, the input context will not be available and <code><a
363: href= "#XML_GetInputContext" >XML_GetInputContext</a></code> will
364: always report NULL. Without this, Expat has a smaller memory
365: footprint and can be faster.</dd>
366:
367: <dt>XML_STATIC</dt>
368: <dd>On Windows, this should be set if Expat is going to be linked
369: statically with the code that calls it; this is required to get all
370: the right MSVC magic annotations correct. This is ignored on other
371: platforms.</dd>
372: </dl>
373:
374: <hr />
375: <h2><a name="using">Using Expat</a></h2>
376:
377: <h3>Compiling and Linking Against Expat</h3>
378:
379: <p>Unless you installed Expat in a location not expected by your
380: compiler and linker, all you have to do to use Expat in your programs
381: is to include the Expat header (<code>#include <expat.h></code>)
382: in your files that make calls to it and to tell the linker that it
383: needs to link against the Expat library. On Unix systems, this would
384: usually be done with the <code>-lexpat</code> argument. Otherwise,
385: you'll need to tell the compiler where to look for the Expat header
386: and the linker where to find the Expat library. You may also need to
387: take steps to tell the operating system where to find this library at
388: run time.</p>
389:
390: <p>On a Unix-based system, here's what a Makefile might look like when
391: Expat is installed in a standard location:</p>
392:
393: <pre class="eg">
394: CC=cc
395: LDFLAGS=
396: LIBS= -lexpat
397: xmlapp: xmlapp.o
398: $(CC) $(LDFLAGS) -o xmlapp xmlapp.o $(LIBS)
399: </pre>
400:
401: <p>If you installed Expat in, say, <code>/home/me/mystuff</code>, then
402: the Makefile would look like this:</p>
403:
404: <pre class="eg">
405: CC=cc
406: CFLAGS= -I/home/me/mystuff/include
407: LDFLAGS=
408: LIBS= -L/home/me/mystuff/lib -lexpat
409: xmlapp: xmlapp.o
410: $(CC) $(LDFLAGS) -o xmlapp xmlapp.o $(LIBS)
411: </pre>
412:
413: <p>You'd also have to set the environment variable
414: <code>LD_LIBRARY_PATH</code> to <code>/home/me/mystuff/lib</code> (or
415: to <code>${LD_LIBRARY_PATH}:/home/me/mystuff/lib</code> if
416: LD_LIBRARY_PATH already has some directories in it) in order to run
417: your application.</p>
418:
419: <h3>Expat Basics</h3>
420:
421: <p>As we saw in the example in the overview, the first step in parsing
422: an XML document with Expat is to create a parser object. There are <a
423: href="#creation">three functions</a> in the Expat API for creating a
424: parser object. However, only two of these (<code><a href=
425: "#XML_ParserCreate" >XML_ParserCreate</a></code> and <code><a href=
426: "#XML_ParserCreateNS" >XML_ParserCreateNS</a></code>) can be used for
427: constructing a parser for a top-level document. The object returned
428: by these functions is an opaque pointer (i.e. "expat.h" declares it as
429: void *) to data with further internal structure. In order to free the
430: memory associated with this object you must call <code><a href=
431: "#XML_ParserFree" >XML_ParserFree</a></code>. Note that if you have
432: provided any <a href="#userdata">user data</a> that gets stored in the
433: parser, then your application is responsible for freeing it prior to
434: calling <code>XML_ParserFree</code>.</p>
435:
436: <p>The objects returned by the parser creation functions are good for
437: parsing only one XML document or external parsed entity. If your
438: application needs to parse many XML documents, then it needs to create
439: a parser object for each one. The best way to deal with this is to
440: create a higher level object that contains all the default
441: initialization you want for your parser objects.</p>
442:
443: <p>Walking through a document hierarchy with a stream oriented parser
444: will require a good stack mechanism in order to keep track of current
445: context. For instance, to answer the simple question, "What element
446: does this text belong to?" requires a stack, since the parser may have
447: descended into other elements that are children of the current one and
448: has encountered this text on the way out.</p>
449:
450: <p>The things you're likely to want to keep on a stack are the
451: currently opened element and it's attributes. You push this
452: information onto the stack in the start handler and you pop it off in
453: the end handler.</p>
454:
455: <p>For some tasks, it is sufficient to just keep information on what
456: the depth of the stack is (or would be if you had one.) The outline
457: program shown above presents one example. Another such task would be
458: skipping over a complete element. When you see the start tag for the
459: element you want to skip, you set a skip flag and record the depth at
460: which the element started. When the end tag handler encounters the
461: same depth, the skipped element has ended and the flag may be
462: cleared. If you follow the convention that the root element starts at
463: 1, then you can use the same variable for skip flag and skip
464: depth.</p>
465:
466: <pre class="eg">
467: void
468: init_info(Parseinfo *info) {
469: info->skip = 0;
470: info->depth = 1;
471: /* Other initializations here */
472: } /* End of init_info */
473:
474: void XMLCALL
475: rawstart(void *data, const char *el, const char **attr) {
476: Parseinfo *inf = (Parseinfo *) data;
477:
478: if (! inf->skip) {
479: if (should_skip(inf, el, attr)) {
480: inf->skip = inf->depth;
481: }
482: else
483: start(inf, el, attr); /* This does rest of start handling */
484: }
485:
486: inf->depth++;
487: } /* End of rawstart */
488:
489: void XMLCALL
490: rawend(void *data, const char *el) {
491: Parseinfo *inf = (Parseinfo *) data;
492:
493: inf->depth--;
494:
495: if (! inf->skip)
496: end(inf, el); /* This does rest of end handling */
497:
498: if (inf->skip == inf->depth)
499: inf->skip = 0;
500: } /* End rawend */
501: </pre>
502:
503: <p>Notice in the above example the difference in how depth is
504: manipulated in the start and end handlers. The end tag handler should
505: be the mirror image of the start tag handler. This is necessary to
506: properly model containment. Since, in the start tag handler, we
507: incremented depth <em>after</em> the main body of start tag code, then
508: in the end handler, we need to manipulate it <em>before</em> the main
509: body. If we'd decided to increment it first thing in the start
510: handler, then we'd have had to decrement it last thing in the end
511: handler.</p>
512:
513: <h3 id="userdata">Communicating between handlers</h3>
514:
515: <p>In order to be able to pass information between different handlers
516: without using globals, you'll need to define a data structure to hold
517: the shared variables. You can then tell Expat (with the <code><a href=
518: "#XML_SetUserData" >XML_SetUserData</a></code> function) to pass a
519: pointer to this structure to the handlers. This is the first
520: argument received by most handlers. In the <a href="#reference"
521: >reference section</a>, an argument to a callback function is named
522: <code>userData</code> and have type <code>void *</code> if the user
523: data is passed; it will have the type <code>XML_Parser</code> if the
524: parser itself is passed. When the parser is passed, the user data may
525: be retrieved using <code><a href="#XML_GetUserData"
526: >XML_GetUserData</a></code>.</p>
527:
528: <p>One common case where multiple calls to a single handler may need
529: to communicate using an application data structure is the case when
530: content passed to the character data handler (set by <code><a href=
531: "#XML_SetCharacterDataHandler"
532: >XML_SetCharacterDataHandler</a></code>) needs to be accumulated. A
533: common first-time mistake with any of the event-oriented interfaces to
534: an XML parser is to expect all the text contained in an element to be
535: reported by a single call to the character data handler. Expat, like
536: many other XML parsers, reports such data as a sequence of calls;
537: there's no way to know when the end of the sequence is reached until a
538: different callback is made. A buffer referenced by the user data
539: structure proves both an effective and convenient place to accumulate
540: character data.</p>
541:
542: <!-- XXX example needed here -->
543:
544:
545: <h3>XML Version</h3>
546:
547: <p>Expat is an XML 1.0 parser, and as such never complains based on
548: the value of the <code>version</code> pseudo-attribute in the XML
549: declaration, if present.</p>
550:
551: <p>If an application needs to check the version number (to support
552: alternate processing), it should use the <code><a href=
553: "#XML_SetXmlDeclHandler" >XML_SetXmlDeclHandler</a></code> function to
554: set a handler that uses the information in the XML declaration to
555: determine what to do. This example shows how to check that only a
556: version number of <code>"1.0"</code> is accepted:</p>
557:
558: <pre class="eg">
559: static int wrong_version;
560: static XML_Parser parser;
561:
562: static void XMLCALL
563: xmldecl_handler(void *userData,
564: const XML_Char *version,
565: const XML_Char *encoding,
566: int standalone)
567: {
568: static const XML_Char Version_1_0[] = {'1', '.', '0', 0};
569:
570: int i;
571:
572: for (i = 0; i < (sizeof(Version_1_0) / sizeof(Version_1_0[0])); ++i) {
573: if (version[i] != Version_1_0[i]) {
574: wrong_version = 1;
575: /* also clear all other handlers: */
576: XML_SetCharacterDataHandler(parser, NULL);
577: ...
578: return;
579: }
580: }
581: ...
582: }
583: </pre>
584:
585: <h3>Namespace Processing</h3>
586:
587: <p>When the parser is created using the <code><a href=
588: "#XML_ParserCreateNS" >XML_ParserCreateNS</a></code>, function, Expat
589: performs namespace processing. Under namespace processing, Expat
590: consumes <code>xmlns</code> and <code>xmlns:...</code> attributes,
591: which declare namespaces for the scope of the element in which they
592: occur. This means that your start handler will not see these
593: attributes. Your application can still be informed of these
594: declarations by setting namespace declaration handlers with <a href=
595: "#XML_SetNamespaceDeclHandler"
596: ><code>XML_SetNamespaceDeclHandler</code></a>.</p>
597:
598: <p>Element type and attribute names that belong to a given namespace
599: are passed to the appropriate handler in expanded form. By default
600: this expanded form is a concatenation of the namespace URI, the
601: separator character (which is the 2nd argument to <code><a href=
602: "#XML_ParserCreateNS" >XML_ParserCreateNS</a></code>), and the local
603: name (i.e. the part after the colon). Names with undeclared prefixes
604: are not well-formed when namespace processing is enabled, and will
605: trigger an error. Unprefixed attribute names are never expanded,
606: and unprefixed element names are only expanded when they are in the
607: scope of a default namespace.</p>
608:
609: <p>However if <code><a href= "#XML_SetReturnNSTriplet"
610: >XML_SetReturnNSTriplet</a></code> has been called with a non-zero
611: <code>do_nst</code> parameter, then the expanded form for names with
612: an explicit prefix is a concatenation of: URI, separator, local name,
613: separator, prefix.</p>
614:
615: <p>You can set handlers for the start of a namespace declaration and
616: for the end of a scope of a declaration with the <code><a href=
617: "#XML_SetNamespaceDeclHandler" >XML_SetNamespaceDeclHandler</a></code>
618: function. The StartNamespaceDeclHandler is called prior to the start
619: tag handler and the EndNamespaceDeclHandler is called after the
620: corresponding end tag that ends the namespace's scope. The namespace
621: start handler gets passed the prefix and URI for the namespace. For a
622: default namespace declaration (xmlns='...'), the prefix will be null.
623: The URI will be null for the case where the default namespace is being
624: unset. The namespace end handler just gets the prefix for the closing
625: scope.</p>
626:
627: <p>These handlers are called for each declaration. So if, for
628: instance, a start tag had three namespace declarations, then the
629: StartNamespaceDeclHandler would be called three times before the start
630: tag handler is called, once for each declaration.</p>
631:
632: <h3>Character Encodings</h3>
633:
634: <p>While XML is based on Unicode, and every XML processor is required
635: to recognized UTF-8 and UTF-16 (1 and 2 byte encodings of Unicode),
636: other encodings may be declared in XML documents or entities. For the
637: main document, an XML declaration may contain an encoding
638: declaration:</p>
639: <pre>
640: <?xml version="1.0" encoding="ISO-8859-2"?>
641: </pre>
642:
643: <p>External parsed entities may begin with a text declaration, which
644: looks like an XML declaration with just an encoding declaration:</p>
645: <pre>
646: <?xml encoding="Big5"?>
647: </pre>
648:
649: <p>With Expat, you may also specify an encoding at the time of
650: creating a parser. This is useful when the encoding information may
651: come from a source outside the document itself (like a higher level
652: protocol.)</p>
653:
654: <p><a name="builtin_encodings"></a>There are four built-in encodings
655: in Expat:</p>
656: <ul>
657: <li>UTF-8</li>
658: <li>UTF-16</li>
659: <li>ISO-8859-1</li>
660: <li>US-ASCII</li>
661: </ul>
662:
663: <p>Anything else discovered in an encoding declaration or in the
664: protocol encoding specified in the parser constructor, triggers a call
665: to the <code>UnknownEncodingHandler</code>. This handler gets passed
666: the encoding name and a pointer to an <code>XML_Encoding</code> data
667: structure. Your handler must fill in this structure and return
668: <code>XML_STATUS_OK</code> if it knows how to deal with the
669: encoding. Otherwise the handler should return
670: <code>XML_STATUS_ERROR</code>. The handler also gets passed a pointer
671: to an optional application data structure that you may indicate when
672: you set the handler.</p>
673:
674: <p>Expat places restrictions on character encodings that it can
675: support by filling in the <code>XML_Encoding</code> structure.
676: include file:</p>
677: <ol>
678: <li>Every ASCII character that can appear in a well-formed XML document
679: must be represented by a single byte, and that byte must correspond to
680: it's ASCII encoding (except for the characters $@\^'{}~)</li>
681: <li>Characters must be encoded in 4 bytes or less.</li>
682: <li>All characters encoded must have Unicode scalar values less than or
683: equal to 65535 (0xFFFF)<em>This does not apply to the built-in support
684: for UTF-16 and UTF-8</em></li>
685: <li>No character may be encoded by more that one distinct sequence of
686: bytes</li>
687: </ol>
688:
689: <p><code>XML_Encoding</code> contains an array of integers that
690: correspond to the 1st byte of an encoding sequence. If the value in
691: the array for a byte is zero or positive, then the byte is a single
692: byte encoding that encodes the Unicode scalar value contained in the
693: array. A -1 in this array indicates a malformed byte. If the value is
694: -2, -3, or -4, then the byte is the beginning of a 2, 3, or 4 byte
695: sequence respectively. Multi-byte sequences are sent to the convert
696: function pointed at in the <code>XML_Encoding</code> structure. This
697: function should return the Unicode scalar value for the sequence or -1
698: if the sequence is malformed.</p>
699:
700: <p>One pitfall that novice Expat users are likely to fall into is that
701: although Expat may accept input in various encodings, the strings that
702: it passes to the handlers are always encoded in UTF-8 or UTF-16
703: (depending on how Expat was compiled). Your application is responsible
704: for any translation of these strings into other encodings.</p>
705:
706: <h3>Handling External Entity References</h3>
707:
708: <p>Expat does not read or parse external entities directly. Note that
709: any external DTD is a special case of an external entity. If you've
710: set no <code>ExternalEntityRefHandler</code>, then external entity
711: references are silently ignored. Otherwise, it calls your handler with
712: the information needed to read and parse the external entity.</p>
713:
714: <p>Your handler isn't actually responsible for parsing the entity, but
715: it is responsible for creating a subsidiary parser with <code><a href=
716: "#XML_ExternalEntityParserCreate"
717: >XML_ExternalEntityParserCreate</a></code> that will do the job. This
718: returns an instance of <code>XML_Parser</code> that has handlers and
719: other data structures initialized from the parent parser. You may then
720: use <code><a href= "#XML_Parse" >XML_Parse</a></code> or <code><a
721: href= "#XML_ParseBuffer">XML_ParseBuffer</a></code> calls against this
722: parser. Since external entities my refer to other external entities,
723: your handler should be prepared to be called recursively.</p>
724:
725: <h3>Parsing DTDs</h3>
726:
727: <p>In order to parse parameter entities, before starting the parse,
728: you must call <code><a href= "#XML_SetParamEntityParsing"
729: >XML_SetParamEntityParsing</a></code> with one of the following
730: arguments:</p>
731: <dl>
732: <dt><code>XML_PARAM_ENTITY_PARSING_NEVER</code></dt>
733: <dd>Don't parse parameter entities or the external subset</dd>
734: <dt><code>XML_PARAM_ENTITY_PARSING_UNLESS_STANDALONE</code></dt>
735: <dd>Parse parameter entites and the external subset unless
736: <code>standalone</code> was set to "yes" in the XML declaration.</dd>
737: <dt><code>XML_PARAM_ENTITY_PARSING_ALWAYS</code></dt>
738: <dd>Always parse parameter entities and the external subset</dd>
739: </dl>
740:
741: <p>In order to read an external DTD, you also have to set an external
742: entity reference handler as described above.</p>
743:
744: <h3 id="stop-resume">Temporarily Stopping Parsing</h3>
745:
746: <p>Expat 1.95.8 introduces a new feature: its now possible to stop
747: parsing temporarily from within a handler function, even if more data
748: has already been passed into the parser. Applications for this
749: include</p>
750:
751: <ul>
752: <li>Supporting the <a href= "http://www.w3.org/TR/xinclude/"
753: >XInclude</a> specification.</li>
754:
755: <li>Delaying further processing until additional information is
756: available from some other source.</li>
757:
758: <li>Adjusting processor load as task priorities shift within an
759: application.</li>
760:
761: <li>Stopping parsing completely (simply free or reset the parser
762: instead of resuming in the outer parsing loop). This can be useful
763: if a application-domain error is found in the XML being parsed or if
764: the result of the parse is determined not to be useful after
765: all.</li>
766: </ul>
767:
768: <p>To take advantage of this feature, the main parsing loop of an
769: application needs to support this specifically. It cannot be
770: supported with a parsing loop compatible with Expat 1.95.7 or
771: earlier (though existing loops will continue to work without
772: supporting the stop/resume feature).</p>
773:
774: <p>An application that uses this feature for a single parser will have
775: the rough structure (in pseudo-code):</p>
776:
777: <pre class="pseudocode">
778: fd = open_input()
779: p = create_parser()
780:
781: if parse_xml(p, fd) {
782: /* suspended */
783:
784: int suspended = 1;
785:
786: while (suspended) {
787: do_something_else()
788: if ready_to_resume() {
789: suspended = continue_parsing(p, fd);
790: }
791: }
792: }
793: </pre>
794:
795: <p>An application that may resume any of several parsers based on
796: input (either from the XML being parsed or some other source) will
797: certainly have more interesting control structures.</p>
798:
799: <p>This C function could be used for the <code>parse_xml</code>
800: function mentioned in the pseudo-code above:</p>
801:
802: <pre class="eg">
803: #define BUFF_SIZE 10240
804:
805: /* Parse a document from the open file descriptor 'fd' until the parse
806: is complete (the document has been completely parsed, or there's
807: been an error), or the parse is stopped. Return non-zero when
808: the parse is merely suspended.
809: */
810: int
811: parse_xml(XML_Parser p, int fd)
812: {
813: for (;;) {
814: int last_chunk;
815: int bytes_read;
816: enum XML_Status status;
817:
818: void *buff = XML_GetBuffer(p, BUFF_SIZE);
819: if (buff == NULL) {
820: /* handle error... */
821: return 0;
822: }
823: bytes_read = read(fd, buff, BUFF_SIZE);
824: if (bytes_read < 0) {
825: /* handle error... */
826: return 0;
827: }
828: status = XML_ParseBuffer(p, bytes_read, bytes_read == 0);
829: switch (status) {
830: case XML_STATUS_ERROR:
831: /* handle error... */
832: return 0;
833: case XML_STATUS_SUSPENDED:
834: return 1;
835: }
836: if (bytes_read == 0)
837: return 0;
838: }
839: }
840: </pre>
841:
842: <p>The corresponding <code>continue_parsing</code> function is
843: somewhat simpler, since it only need deal with the return code from
844: <code><a href= "#XML_ResumeParser">XML_ResumeParser</a></code>; it can
845: delegate the input handling to the <code>parse_xml</code>
846: function:</p>
847:
848: <pre class="eg">
849: /* Continue parsing a document which had been suspended. The 'p' and
850: 'fd' arguments are the same as passed to parse_xml(). Return
851: non-zero when the parse is suspended.
852: */
853: int
854: continue_parsing(XML_Parser p, int fd)
855: {
856: enum XML_Status status = XML_ResumeParser(p);
857: switch (status) {
858: case XML_STATUS_ERROR:
859: /* handle error... */
860: return 0;
861: case XML_ERROR_NOT_SUSPENDED:
862: /* handle error... */
863: return 0;.
864: case XML_STATUS_SUSPENDED:
865: return 1;
866: }
867: return parse_xml(p, fd);
868: }
869: </pre>
870:
871: <p>Now that we've seen what a mess the top-level parsing loop can
872: become, what have we gained? Very simply, we can now use the <code><a
873: href= "#XML_StopParser" >XML_StopParser</a></code> function to stop
874: parsing, without having to go to great lengths to avoid additional
875: processing that we're expecting to ignore. As a bonus, we get to stop
876: parsing <em>temporarily</em>, and come back to it when we're
877: ready.</p>
878:
879: <p>To stop parsing from a handler function, use the <code><a href=
880: "#XML_StopParser" >XML_StopParser</a></code> function. This function
881: takes two arguments; the parser being stopped and a flag indicating
882: whether the parse can be resumed in the future.</p>
883:
884: <!-- XXX really need more here -->
885:
886:
887: <hr />
888: <!-- ================================================================ -->
889:
890: <h2><a name="reference">Expat Reference</a></h2>
891:
892: <h3><a name="creation">Parser Creation</a></h3>
893:
894: <pre class="fcndec" id="XML_ParserCreate">
895: XML_Parser XMLCALL
896: XML_ParserCreate(const XML_Char *encoding);
897: </pre>
898: <div class="fcndef">
899: Construct a new parser. If encoding is non-null, it specifies a
900: character encoding to use for the document. This overrides the document
901: encoding declaration. There are four built-in encodings:
902: <ul>
903: <li>US-ASCII</li>
904: <li>UTF-8</li>
905: <li>UTF-16</li>
906: <li>ISO-8859-1</li>
907: </ul>
908: Any other value will invoke a call to the UnknownEncodingHandler.
909: </div>
910:
911: <pre class="fcndec" id="XML_ParserCreateNS">
912: XML_Parser XMLCALL
913: XML_ParserCreateNS(const XML_Char *encoding,
914: XML_Char sep);
915: </pre>
916: <div class="fcndef">
917: Constructs a new parser that has namespace processing in effect. Namespace
918: expanded element names and attribute names are returned as a concatenation
919: of the namespace URI, <em>sep</em>, and the local part of the name. This
920: means that you should pick a character for <em>sep</em> that can't be
921: part of a legal URI. There is a special case when <em>sep</em> is the null
922: character <code>'\0'</code>: the namespace URI and the local part will be
923: concatenated without any separator - this is intended to support RDF processors.
924: It is a programming error to use the null separator with
925: <a href= "#XML_SetReturnNSTriplet">namespace triplets</a>.</div>
926:
927: <pre class="fcndec" id="XML_ParserCreate_MM">
928: XML_Parser XMLCALL
929: XML_ParserCreate_MM(const XML_Char *encoding,
930: const XML_Memory_Handling_Suite *ms,
931: const XML_Char *sep);
932: </pre>
933: <pre class="signature">
934: typedef struct {
935: void *(XMLCALL *malloc_fcn)(size_t size);
936: void *(XMLCALL *realloc_fcn)(void *ptr, size_t size);
937: void (XMLCALL *free_fcn)(void *ptr);
938: } XML_Memory_Handling_Suite;
939: </pre>
940: <div class="fcndef">
941: <p>Construct a new parser using the suite of memory handling functions
942: specified in <code>ms</code>. If <code>ms</code> is NULL, then use the
943: standard set of memory management functions. If <code>sep</code> is
944: non NULL, then namespace processing is enabled in the created parser
945: and the character pointed at by sep is used as the separator between
946: the namespace URI and the local part of the name.</p>
947: </div>
948:
949: <pre class="fcndec" id="XML_ExternalEntityParserCreate">
950: XML_Parser XMLCALL
951: XML_ExternalEntityParserCreate(XML_Parser p,
952: const XML_Char *context,
953: const XML_Char *encoding);
954: </pre>
955: <div class="fcndef">
956: Construct a new <code>XML_Parser</code> object for parsing an external
957: general entity. Context is the context argument passed in a call to a
958: ExternalEntityRefHandler. Other state information such as handlers,
959: user data, namespace processing is inherited from the parser passed as
960: the 1st argument. So you shouldn't need to call any of the behavior
961: changing functions on this parser (unless you want it to act
962: differently than the parent parser).
963: </div>
964:
965: <pre class="fcndec" id="XML_ParserFree">
966: void XMLCALL
967: XML_ParserFree(XML_Parser p);
968: </pre>
969: <div class="fcndef">
970: Free memory used by the parser. Your application is responsible for
971: freeing any memory associated with <a href="#userdata">user data</a>.
972: </div>
973:
974: <pre class="fcndec" id="XML_ParserReset">
975: XML_Bool XMLCALL
976: XML_ParserReset(XML_Parser p,
977: const XML_Char *encoding);
978: </pre>
979: <div class="fcndef">
980: Clean up the memory structures maintained by the parser so that it may
981: be used again. After this has been called, <code>parser</code> is
982: ready to start parsing a new document. All handlers are cleared from
983: the parser, except for the unknownEncodingHandler. The parser's external
984: state is re-initialized except for the values of ns and ns_triplets.
985: This function may not be used on a parser created using <code><a href=
986: "#XML_ExternalEntityParserCreate" >XML_ExternalEntityParserCreate</a
987: ></code>; it will return <code>XML_FALSE</code> in that case. Returns
988: <code>XML_TRUE</code> on success. Your application is responsible for
989: dealing with any memory associated with <a href="#userdata">user data</a>.
990: </div>
991:
992: <h3><a name="parsing">Parsing</a></h3>
993:
994: <p>To state the obvious: the three parsing functions <code><a href=
995: "#XML_Parse" >XML_Parse</a></code>, <code><a href= "#XML_ParseBuffer">
996: XML_ParseBuffer</a></code> and <code><a href= "#XML_GetBuffer">
997: XML_GetBuffer</a></code> must not be called from within a handler
998: unless they operate on a separate parser instance, that is, one that
999: did not call the handler. For example, it is OK to call the parsing
1000: functions from within an <code>XML_ExternalEntityRefHandler</code>,
1001: if they apply to the parser created by
1002: <code><a href= "#XML_ExternalEntityParserCreate"
1003: >XML_ExternalEntityParserCreate</a></code>.</p>
1004:
1005: <p>Note: the <code>len</code> argument passed to these functions
1006: should be considerably less than the maximum value for an integer,
1007: as it could create an integer overflow situation if the added
1008: lengths of a buffer and the unprocessed portion of the previous buffer
1009: exceed the maximum integer value. Input data at the end of a buffer
1010: will remain unprocessed if it is part of an XML token for which the
1011: end is not part of that buffer.</p>
1012:
1013: <pre class="fcndec" id="XML_Parse">
1014: enum XML_Status XMLCALL
1015: XML_Parse(XML_Parser p,
1016: const char *s,
1017: int len,
1018: int isFinal);
1019: </pre>
1020: <pre class="signature">
1021: enum XML_Status {
1022: XML_STATUS_ERROR = 0,
1023: XML_STATUS_OK = 1
1024: };
1025: </pre>
1026: <div class="fcndef">
1027: Parse some more of the document. The string <code>s</code> is a buffer
1028: containing part (or perhaps all) of the document. The number of bytes of s
1029: that are part of the document is indicated by <code>len</code>. This means
1030: that <code>s</code> doesn't have to be null terminated. It also means that
1031: if <code>len</code> is larger than the number of bytes in the block of
1032: memory that <code>s</code> points at, then a memory fault is likely. The
1033: <code>isFinal</code> parameter informs the parser that this is the last
1034: piece of the document. Frequently, the last piece is empty (i.e.
1035: <code>len</code> is zero.)
1036: If a parse error occurred, it returns <code>XML_STATUS_ERROR</code>.
1037: Otherwise it returns <code>XML_STATUS_OK</code> value.
1038: </div>
1039:
1040: <pre class="fcndec" id="XML_ParseBuffer">
1041: enum XML_Status XMLCALL
1042: XML_ParseBuffer(XML_Parser p,
1043: int len,
1044: int isFinal);
1045: </pre>
1046: <div class="fcndef">
1047: This is just like <code><a href= "#XML_Parse" >XML_Parse</a></code>,
1048: except in this case Expat provides the buffer. By obtaining the
1049: buffer from Expat with the <code><a href= "#XML_GetBuffer"
1050: >XML_GetBuffer</a></code> function, the application can avoid double
1051: copying of the input.
1052: </div>
1053:
1054: <pre class="fcndec" id="XML_GetBuffer">
1055: void * XMLCALL
1056: XML_GetBuffer(XML_Parser p,
1057: int len);
1058: </pre>
1059: <div class="fcndef">
1060: Obtain a buffer of size <code>len</code> to read a piece of the document
1061: into. A NULL value is returned if Expat can't allocate enough memory for
1062: this buffer. This has to be called prior to every call to
1063: <code><a href= "#XML_ParseBuffer" >XML_ParseBuffer</a></code>. A
1064: typical use would look like this:
1065:
1066: <pre class="eg">
1067: for (;;) {
1068: int bytes_read;
1069: void *buff = XML_GetBuffer(p, BUFF_SIZE);
1070: if (buff == NULL) {
1071: /* handle error */
1072: }
1073:
1074: bytes_read = read(docfd, buff, BUFF_SIZE);
1075: if (bytes_read < 0) {
1076: /* handle error */
1077: }
1078:
1079: if (! XML_ParseBuffer(p, bytes_read, bytes_read == 0)) {
1080: /* handle parse error */
1081: }
1082:
1083: if (bytes_read == 0)
1084: break;
1085: }
1086: </pre>
1087: </div>
1088:
1089: <pre class="fcndec" id="XML_StopParser">
1090: enum XML_Status XMLCALL
1091: XML_StopParser(XML_Parser p,
1092: XML_Bool resumable);
1093: </pre>
1094: <div class="fcndef">
1095:
1096: <p>Stops parsing, causing <code><a href= "#XML_Parse"
1097: >XML_Parse</a></code> or <code><a href= "#XML_ParseBuffer"
1098: >XML_ParseBuffer</a></code> to return. Must be called from within a
1099: call-back handler, except when aborting (when <code>resumable</code>
1100: is <code>XML_FALSE</code>) an already suspended parser. Some
1101: call-backs may still follow because they would otherwise get
1102: lost, including
1103: <ul>
1104: <li> the end element handler for empty elements when stopped in the
1105: start element handler,</li>
1106: <li> the end namespace declaration handler when stopped in the end
1107: element handler,</li>
1108: <li> the character data handler when stopped in the character data handler
1109: while making multiple call-backs on a contiguous chunk of characters,</li>
1110: </ul>
1111: and possibly others.</p>
1112:
1113: <p>This can be called from most handlers, including DTD related
1114: call-backs, except when parsing an external parameter entity and
1115: <code>resumable</code> is <code>XML_TRUE</code>. Returns
1116: <code>XML_STATUS_OK</code> when successful,
1117: <code>XML_STATUS_ERROR</code> otherwise. The possible error codes
1118: are:</p>
1119: <dl>
1120: <dt><code>XML_ERROR_SUSPENDED</code></dt>
1121: <dd>when suspending an already suspended parser.</dd>
1122: <dt><code>XML_ERROR_FINISHED</code></dt>
1123: <dd>when the parser has already finished.</dd>
1124: <dt><code>XML_ERROR_SUSPEND_PE</code></dt>
1125: <dd>when suspending while parsing an external PE.</dd>
1126: </dl>
1127:
1128: <p>Since the stop/resume feature requires application support in the
1129: outer parsing loop, it is an error to call this function for a parser
1130: not being handled appropriately; see <a href= "#stop-resume"
1131: >Temporarily Stopping Parsing</a> for more information.</p>
1132:
1133: <p>When <code>resumable</code> is <code>XML_TRUE</code> then parsing
1134: is <em>suspended</em>, that is, <code><a href= "#XML_Parse"
1135: >XML_Parse</a></code> and <code><a href= "#XML_ParseBuffer"
1136: >XML_ParseBuffer</a></code> return <code>XML_STATUS_SUSPENDED</code>.
1137: Otherwise, parsing is <em>aborted</em>, that is, <code><a href=
1138: "#XML_Parse" >XML_Parse</a></code> and <code><a href=
1139: "#XML_ParseBuffer" >XML_ParseBuffer</a></code> return
1140: <code>XML_STATUS_ERROR</code> with error code
1141: <code>XML_ERROR_ABORTED</code>.</p>
1142:
1143: <p><strong>Note:</strong>
1144: This will be applied to the current parser instance only, that is, if
1145: there is a parent parser then it will continue parsing when the
1146: external entity reference handler returns. It is up to the
1147: implementation of that handler to call <code><a href=
1148: "#XML_StopParser" >XML_StopParser</a></code> on the parent parser
1149: (recursively), if one wants to stop parsing altogether.</p>
1150:
1151: <p>When suspended, parsing can be resumed by calling <code><a href=
1152: "#XML_ResumeParser" >XML_ResumeParser</a></code>.</p>
1153:
1154: <p>New in Expat 1.95.8.</p>
1155: </div>
1156:
1157: <pre class="fcndec" id="XML_ResumeParser">
1158: enum XML_Status XMLCALL
1159: XML_ResumeParser(XML_Parser p);
1160: </pre>
1161: <div class="fcndef">
1162: <p>Resumes parsing after it has been suspended with <code><a href=
1163: "#XML_StopParser" >XML_StopParser</a></code>. Must not be called from
1164: within a handler call-back. Returns same status codes as <code><a
1165: href= "#XML_Parse">XML_Parse</a></code> or <code><a href=
1166: "#XML_ParseBuffer" >XML_ParseBuffer</a></code>. An additional error
1167: code, <code>XML_ERROR_NOT_SUSPENDED</code>, will be returned if the
1168: parser was not currently suspended.</p>
1169:
1170: <p><strong>Note:</strong>
1171: This must be called on the most deeply nested child parser instance
1172: first, and on its parent parser only after the child parser has
1173: finished, to be applied recursively until the document entity's parser
1174: is restarted. That is, the parent parser will not resume by itself
1175: and it is up to the application to call <code><a href=
1176: "#XML_ResumeParser" >XML_ResumeParser</a></code> on it at the
1177: appropriate moment.</p>
1178:
1179: <p>New in Expat 1.95.8.</p>
1180: </div>
1181:
1182: <pre class="fcndec" id="XML_GetParsingStatus">
1183: void XMLCALL
1184: XML_GetParsingStatus(XML_Parser p,
1185: XML_ParsingStatus *status);
1186: </pre>
1187: <pre class="signature">
1188: enum XML_Parsing {
1189: XML_INITIALIZED,
1190: XML_PARSING,
1191: XML_FINISHED,
1192: XML_SUSPENDED
1193: };
1194:
1195: typedef struct {
1196: enum XML_Parsing parsing;
1197: XML_Bool finalBuffer;
1198: } XML_ParsingStatus;
1199: </pre>
1200: <div class="fcndef">
1201: <p>Returns status of parser with respect to being initialized,
1202: parsing, finished, or suspended, and whether the final buffer is being
1203: processed. The <code>status</code> parameter <em>must not</em> be
1204: NULL.</p>
1205:
1206: <p>New in Expat 1.95.8.</p>
1207: </div>
1208:
1209:
1210: <h3><a name="setting">Handler Setting</a></h3>
1211:
1212: <p>Although handlers are typically set prior to parsing and left alone, an
1213: application may choose to set or change the handler for a parsing event
1214: while the parse is in progress. For instance, your application may choose
1215: to ignore all text not descended from a <code>para</code> element. One
1216: way it could do this is to set the character handler when a para start tag
1217: is seen, and unset it for the corresponding end tag.</p>
1218:
1219: <p>A handler may be <em>unset</em> by providing a NULL pointer to the
1220: appropriate handler setter. None of the handler setting functions have
1221: a return value.</p>
1222:
1223: <p>Your handlers will be receiving strings in arrays of type
1224: <code>XML_Char</code>. This type is conditionally defined in expat.h as
1225: either <code>char</code>, <code>wchar_t</code> or <code>unsigned short</code>.
1226: The former implies UTF-8 encoding, the latter two imply UTF-16 encoding.
1227: Note that you'll receive them in this form independent of the original
1228: encoding of the document.</p>
1229:
1230: <div class="handler">
1231: <pre class="setter" id="XML_SetStartElementHandler">
1232: void XMLCALL
1233: XML_SetStartElementHandler(XML_Parser p,
1234: XML_StartElementHandler start);
1235: </pre>
1236: <pre class="signature">
1237: typedef void
1238: (XMLCALL *XML_StartElementHandler)(void *userData,
1239: const XML_Char *name,
1240: const XML_Char **atts);
1241: </pre>
1242: <p>Set handler for start (and empty) tags. Attributes are passed to the start
1243: handler as a pointer to a vector of char pointers. Each attribute seen in
1244: a start (or empty) tag occupies 2 consecutive places in this vector: the
1245: attribute name followed by the attribute value. These pairs are terminated
1246: by a null pointer.</p>
1247: <p>Note that an empty tag generates a call to both start and end handlers
1248: (in that order).</p>
1249: </div>
1250:
1251: <div class="handler">
1252: <pre class="setter" id="XML_SetEndElementHandler">
1253: void XMLCALL
1254: XML_SetEndElementHandler(XML_Parser p,
1255: XML_EndElementHandler);
1256: </pre>
1257: <pre class="signature">
1258: typedef void
1259: (XMLCALL *XML_EndElementHandler)(void *userData,
1260: const XML_Char *name);
1261: </pre>
1262: <p>Set handler for end (and empty) tags. As noted above, an empty tag
1263: generates a call to both start and end handlers.</p>
1264: </div>
1265:
1266: <div class="handler">
1267: <pre class="setter" id="XML_SetElementHandler">
1268: void XMLCALL
1269: XML_SetElementHandler(XML_Parser p,
1270: XML_StartElementHandler start,
1271: XML_EndElementHandler end);
1272: </pre>
1273: <p>Set handlers for start and end tags with one call.</p>
1274: </div>
1275:
1276: <div class="handler">
1277: <pre class="setter" id="XML_SetCharacterDataHandler">
1278: void XMLCALL
1279: XML_SetCharacterDataHandler(XML_Parser p,
1280: XML_CharacterDataHandler charhndl)
1281: </pre>
1282: <pre class="signature">
1283: typedef void
1284: (XMLCALL *XML_CharacterDataHandler)(void *userData,
1285: const XML_Char *s,
1286: int len);
1287: </pre>
1288: <p>Set a text handler. The string your handler receives
1289: is <em>NOT nul-terminated</em>. You have to use the length argument
1290: to deal with the end of the string. A single block of contiguous text
1291: free of markup may still result in a sequence of calls to this handler.
1292: In other words, if you're searching for a pattern in the text, it may
1293: be split across calls to this handler. Note: Setting this handler to NULL
1294: may <em>NOT immediately</em> terminate call-backs if the parser is currently
1295: processing such a single block of contiguous markup-free text, as the parser
1296: will continue calling back until the end of the block is reached.</p>
1297: </div>
1298:
1299: <div class="handler">
1300: <pre class="setter" id="XML_SetProcessingInstructionHandler">
1301: void XMLCALL
1302: XML_SetProcessingInstructionHandler(XML_Parser p,
1303: XML_ProcessingInstructionHandler proc)
1304: </pre>
1305: <pre class="signature">
1306: typedef void
1307: (XMLCALL *XML_ProcessingInstructionHandler)(void *userData,
1308: const XML_Char *target,
1309: const XML_Char *data);
1310:
1311: </pre>
1312: <p>Set a handler for processing instructions. The target is the first word
1313: in the processing instruction. The data is the rest of the characters in
1314: it after skipping all whitespace after the initial word.</p>
1315: </div>
1316:
1317: <div class="handler">
1318: <pre class="setter" id="XML_SetCommentHandler">
1319: void XMLCALL
1320: XML_SetCommentHandler(XML_Parser p,
1321: XML_CommentHandler cmnt)
1322: </pre>
1323: <pre class="signature">
1324: typedef void
1325: (XMLCALL *XML_CommentHandler)(void *userData,
1326: const XML_Char *data);
1327: </pre>
1328: <p>Set a handler for comments. The data is all text inside the comment
1329: delimiters.</p>
1330: </div>
1331:
1332: <div class="handler">
1333: <pre class="setter" id="XML_SetStartCdataSectionHandler">
1334: void XMLCALL
1335: XML_SetStartCdataSectionHandler(XML_Parser p,
1336: XML_StartCdataSectionHandler start);
1337: </pre>
1338: <pre class="signature">
1339: typedef void
1340: (XMLCALL *XML_StartCdataSectionHandler)(void *userData);
1341: </pre>
1342: <p>Set a handler that gets called at the beginning of a CDATA section.</p>
1343: </div>
1344:
1345: <div class="handler">
1346: <pre class="setter" id="XML_SetEndCdataSectionHandler">
1347: void XMLCALL
1348: XML_SetEndCdataSectionHandler(XML_Parser p,
1349: XML_EndCdataSectionHandler end);
1350: </pre>
1351: <pre class="signature">
1352: typedef void
1353: (XMLCALL *XML_EndCdataSectionHandler)(void *userData);
1354: </pre>
1355: <p>Set a handler that gets called at the end of a CDATA section.</p>
1356: </div>
1357:
1358: <div class="handler">
1359: <pre class="setter" id="XML_SetCdataSectionHandler">
1360: void XMLCALL
1361: XML_SetCdataSectionHandler(XML_Parser p,
1362: XML_StartCdataSectionHandler start,
1363: XML_EndCdataSectionHandler end)
1364: </pre>
1365: <p>Sets both CDATA section handlers with one call.</p>
1366: </div>
1367:
1368: <div class="handler">
1369: <pre class="setter" id="XML_SetDefaultHandler">
1370: void XMLCALL
1371: XML_SetDefaultHandler(XML_Parser p,
1372: XML_DefaultHandler hndl)
1373: </pre>
1374: <pre class="signature">
1375: typedef void
1376: (XMLCALL *XML_DefaultHandler)(void *userData,
1377: const XML_Char *s,
1378: int len);
1379: </pre>
1380:
1381: <p>Sets a handler for any characters in the document which wouldn't
1382: otherwise be handled. This includes both data for which no handlers
1383: can be set (like some kinds of DTD declarations) and data which could
1384: be reported but which currently has no handler set. The characters
1385: are passed exactly as they were present in the XML document except
1386: that they will be encoded in UTF-8 or UTF-16. Line boundaries are not
1387: normalized. Note that a byte order mark character is not passed to the
1388: default handler. There are no guarantees about how characters are
1389: divided between calls to the default handler: for example, a comment
1390: might be split between multiple calls. Setting the handler with
1391: this call has the side effect of turning off expansion of references
1392: to internally defined general entities. Instead these references are
1393: passed to the default handler.</p>
1394:
1395: <p>See also <code><a
1396: href="#XML_DefaultCurrent">XML_DefaultCurrent</a></code>.</p>
1397: </div>
1398:
1399: <div class="handler">
1400: <pre class="setter" id="XML_SetDefaultHandlerExpand">
1401: void XMLCALL
1402: XML_SetDefaultHandlerExpand(XML_Parser p,
1403: XML_DefaultHandler hndl)
1404: </pre>
1405: <pre class="signature">
1406: typedef void
1407: (XMLCALL *XML_DefaultHandler)(void *userData,
1408: const XML_Char *s,
1409: int len);
1410: </pre>
1411: <p>This sets a default handler, but doesn't inhibit the expansion of
1412: internal entity references. The entity reference will not be passed
1413: to the default handler.</p>
1414:
1415: <p>See also <code><a
1416: href="#XML_DefaultCurrent">XML_DefaultCurrent</a></code>.</p>
1417: </div>
1418:
1419: <div class="handler">
1420: <pre class="setter" id="XML_SetExternalEntityRefHandler">
1421: void XMLCALL
1422: XML_SetExternalEntityRefHandler(XML_Parser p,
1423: XML_ExternalEntityRefHandler hndl)
1424: </pre>
1425: <pre class="signature">
1426: typedef int
1427: (XMLCALL *XML_ExternalEntityRefHandler)(XML_Parser p,
1428: const XML_Char *context,
1429: const XML_Char *base,
1430: const XML_Char *systemId,
1431: const XML_Char *publicId);
1432: </pre>
1433: <p>Set an external entity reference handler. This handler is also
1434: called for processing an external DTD subset if parameter entity parsing
1435: is in effect. (See <a href="#XML_SetParamEntityParsing">
1436: <code>XML_SetParamEntityParsing</code></a>.)</p>
1437:
1438: <p>The <code>context</code> parameter specifies the parsing context in
1439: the format expected by the <code>context</code> argument to <code><a
1440: href="#XML_ExternalEntityParserCreate"
1441: >XML_ExternalEntityParserCreate</a></code>. <code>code</code> is
1442: valid only until the handler returns, so if the referenced entity is
1443: to be parsed later, it must be copied. <code>context</code> is NULL
1444: only when the entity is a parameter entity, which is how one can
1445: differentiate between general and parameter entities.</p>
1446:
1447: <p>The <code>base</code> parameter is the base to use for relative
1448: system identifiers. It is set by <code><a
1449: href="#XML_SetBase">XML_SetBase</a></code> and may be NULL. The
1450: <code>publicId</code> parameter is the public id given in the entity
1451: declaration and may be NULL. <code>systemId</code> is the system
1452: identifier specified in the entity declaration and is never NULL.</p>
1453:
1454: <p>There are a couple of ways in which this handler differs from
1455: others. First, this handler returns a status indicator (an
1456: integer). <code>XML_STATUS_OK</code> should be returned for successful
1457: handling of the external entity reference. Returning
1458: <code>XML_STATUS_ERROR</code> indicates failure, and causes the
1459: calling parser to return an
1460: <code>XML_ERROR_EXTERNAL_ENTITY_HANDLING</code> error.</p>
1461:
1462: <p>Second, instead of having the user data as its first argument, it
1463: receives the parser that encountered the entity reference. This, along
1464: with the context parameter, may be used as arguments to a call to
1465: <code><a href= "#XML_ExternalEntityParserCreate"
1466: >XML_ExternalEntityParserCreate</a></code>. Using the returned
1467: parser, the body of the external entity can be recursively parsed.</p>
1468:
1469: <p>Since this handler may be called recursively, it should not be saving
1470: information into global or static variables.</p>
1471: </div>
1472:
1473: <pre class="fcndec" id="XML_SetExternalEntityRefHandlerArg">
1474: void XMLCALL
1475: XML_SetExternalEntityRefHandlerArg(XML_Parser p,
1476: void *arg)
1477: </pre>
1478: <div class="fcndef">
1479: <p>Set the argument passed to the ExternalEntityRefHandler. If
1480: <code>arg</code> is not NULL, it is the new value passed to the
1481: handler set using <code><a href="#XML_SetExternalEntityRefHandler"
1482: >XML_SetExternalEntityRefHandler</a></code>; if <code>arg</code> is
1483: NULL, the argument passed to the handler function will be the parser
1484: object itself.</p>
1485:
1486: <p><strong>Note:</strong>
1487: The type of <code>arg</code> and the type of the first argument to the
1488: ExternalEntityRefHandler do not match. This function takes a
1489: <code>void *</code> to be passed to the handler, while the handler
1490: accepts an <code>XML_Parser</code>. This is a historical accident,
1491: but will not be corrected before Expat 2.0 (at the earliest) to avoid
1492: causing compiler warnings for code that's known to work with this
1493: API. It is the responsibility of the application code to know the
1494: actual type of the argument passed to the handler and to manage it
1495: properly.</p>
1496: </div>
1497:
1498: <div class="handler">
1499: <pre class="setter" id="XML_SetSkippedEntityHandler">
1500: void XMLCALL
1501: XML_SetSkippedEntityHandler(XML_Parser p,
1502: XML_SkippedEntityHandler handler)
1503: </pre>
1504: <pre class="signature">
1505: typedef void
1506: (XMLCALL *XML_SkippedEntityHandler)(void *userData,
1507: const XML_Char *entityName,
1508: int is_parameter_entity);
1509: </pre>
1510: <p>Set a skipped entity handler. This is called in two situations:</p>
1511: <ol>
1512: <li>An entity reference is encountered for which no declaration
1513: has been read <em>and</em> this is not an error.</li>
1514: <li>An internal entity reference is read, but not expanded, because
1515: <a href="#XML_SetDefaultHandler"><code>XML_SetDefaultHandler</code></a>
1516: has been called.</li>
1517: </ol>
1518: <p>The <code>is_parameter_entity</code> argument will be non-zero for
1519: a parameter entity and zero for a general entity.</p> <p>Note: skipped
1520: parameter entities in declarations and skipped general entities in
1521: attribute values cannot be reported, because the event would be out of
1522: sync with the reporting of the declarations or attribute values</p>
1523: </div>
1524:
1525: <div class="handler">
1526: <pre class="setter" id="XML_SetUnknownEncodingHandler">
1527: void XMLCALL
1528: XML_SetUnknownEncodingHandler(XML_Parser p,
1529: XML_UnknownEncodingHandler enchandler,
1530: void *encodingHandlerData)
1531: </pre>
1532: <pre class="signature">
1533: typedef int
1534: (XMLCALL *XML_UnknownEncodingHandler)(void *encodingHandlerData,
1535: const XML_Char *name,
1536: XML_Encoding *info);
1537:
1538: typedef struct {
1539: int map[256];
1540: void *data;
1541: int (XMLCALL *convert)(void *data, const char *s);
1542: void (XMLCALL *release)(void *data);
1543: } XML_Encoding;
1544: </pre>
1545: <p>Set a handler to deal with encodings other than the <a
1546: href="#builtin_encodings">built in set</a>. This should be done before
1547: <code><a href= "#XML_Parse" >XML_Parse</a></code> or <code><a href=
1548: "#XML_ParseBuffer" >XML_ParseBuffer</a></code> have been called on the
1549: given parser.</p> <p>If the handler knows how to deal with an encoding
1550: with the given name, it should fill in the <code>info</code> data
1551: structure and return <code>XML_STATUS_OK</code>. Otherwise it
1552: should return <code>XML_STATUS_ERROR</code>. The handler will be called
1553: at most once per parsed (external) entity. The optional application
1554: data pointer <code>encodingHandlerData</code> will be passed back to
1555: the handler.</p>
1556:
1557: <p>The map array contains information for every possible possible leading
1558: byte in a byte sequence. If the corresponding value is >= 0, then it's
1559: a single byte sequence and the byte encodes that Unicode value. If the
1560: value is -1, then that byte is invalid as the initial byte in a sequence.
1561: If the value is -n, where n is an integer > 1, then n is the number of
1562: bytes in the sequence and the actual conversion is accomplished by a
1563: call to the function pointed at by convert. This function may return -1
1564: if the sequence itself is invalid. The convert pointer may be null if
1565: there are only single byte codes. The data parameter passed to the convert
1566: function is the data pointer from <code>XML_Encoding</code>. The
1567: string s is <em>NOT</em> nul-terminated and points at the sequence of
1568: bytes to be converted.</p>
1569:
1570: <p>The function pointed at by <code>release</code> is called by the
1571: parser when it is finished with the encoding. It may be NULL.</p>
1572: </div>
1573:
1574: <div class="handler">
1575: <pre class="setter" id="XML_SetStartNamespaceDeclHandler">
1576: void XMLCALL
1577: XML_SetStartNamespaceDeclHandler(XML_Parser p,
1578: XML_StartNamespaceDeclHandler start);
1579: </pre>
1580: <pre class="signature">
1581: typedef void
1582: (XMLCALL *XML_StartNamespaceDeclHandler)(void *userData,
1583: const XML_Char *prefix,
1584: const XML_Char *uri);
1585: </pre>
1586: <p>Set a handler to be called when a namespace is declared. Namespace
1587: declarations occur inside start tags. But the namespace declaration start
1588: handler is called before the start tag handler for each namespace declared
1589: in that start tag.</p>
1590: </div>
1591:
1592: <div class="handler">
1593: <pre class="setter" id="XML_SetEndNamespaceDeclHandler">
1594: void XMLCALL
1595: XML_SetEndNamespaceDeclHandler(XML_Parser p,
1596: XML_EndNamespaceDeclHandler end);
1597: </pre>
1598: <pre class="signature">
1599: typedef void
1600: (XMLCALL *XML_EndNamespaceDeclHandler)(void *userData,
1601: const XML_Char *prefix);
1602: </pre>
1603: <p>Set a handler to be called when leaving the scope of a namespace
1604: declaration. This will be called, for each namespace declaration,
1605: after the handler for the end tag of the element in which the
1606: namespace was declared.</p>
1607: </div>
1608:
1609: <div class="handler">
1610: <pre class="setter" id="XML_SetNamespaceDeclHandler">
1611: void XMLCALL
1612: XML_SetNamespaceDeclHandler(XML_Parser p,
1613: XML_StartNamespaceDeclHandler start,
1614: XML_EndNamespaceDeclHandler end)
1615: </pre>
1616: <p>Sets both namespace declaration handlers with a single call.</p>
1617: </div>
1618:
1619: <div class="handler">
1620: <pre class="setter" id="XML_SetXmlDeclHandler">
1621: void XMLCALL
1622: XML_SetXmlDeclHandler(XML_Parser p,
1623: XML_XmlDeclHandler xmldecl);
1624: </pre>
1625: <pre class="signature">
1626: typedef void
1627: (XMLCALL *XML_XmlDeclHandler)(void *userData,
1628: const XML_Char *version,
1629: const XML_Char *encoding,
1630: int standalone);
1631: </pre>
1632: <p>Sets a handler that is called for XML declarations and also for
1633: text declarations discovered in external entities. The way to
1634: distinguish is that the <code>version</code> parameter will be NULL
1635: for text declarations. The <code>encoding</code> parameter may be NULL
1636: for an XML declaration. The <code>standalone</code> argument will
1637: contain -1, 0, or 1 indicating respectively that there was no
1638: standalone parameter in the declaration, that it was given as no, or
1639: that it was given as yes.</p>
1640: </div>
1641:
1642: <div class="handler">
1643: <pre class="setter" id="XML_SetStartDoctypeDeclHandler">
1644: void XMLCALL
1645: XML_SetStartDoctypeDeclHandler(XML_Parser p,
1646: XML_StartDoctypeDeclHandler start);
1647: </pre>
1648: <pre class="signature">
1649: typedef void
1650: (XMLCALL *XML_StartDoctypeDeclHandler)(void *userData,
1651: const XML_Char *doctypeName,
1652: const XML_Char *sysid,
1653: const XML_Char *pubid,
1654: int has_internal_subset);
1655: </pre>
1656: <p>Set a handler that is called at the start of a DOCTYPE declaration,
1657: before any external or internal subset is parsed. Both <code>sysid</code>
1658: and <code>pubid</code> may be NULL. The <code>has_internal_subset</code>
1659: will be non-zero if the DOCTYPE declaration has an internal subset.</p>
1660: </div>
1661:
1662: <div class="handler">
1663: <pre class="setter" id="XML_SetEndDoctypeDeclHandler">
1664: void XMLCALL
1665: XML_SetEndDoctypeDeclHandler(XML_Parser p,
1666: XML_EndDoctypeDeclHandler end);
1667: </pre>
1668: <pre class="signature">
1669: typedef void
1670: (XMLCALL *XML_EndDoctypeDeclHandler)(void *userData);
1671: </pre>
1672: <p>Set a handler that is called at the end of a DOCTYPE declaration,
1673: after parsing any external subset.</p>
1674: </div>
1675:
1676: <div class="handler">
1677: <pre class="setter" id="XML_SetDoctypeDeclHandler">
1678: void XMLCALL
1679: XML_SetDoctypeDeclHandler(XML_Parser p,
1680: XML_StartDoctypeDeclHandler start,
1681: XML_EndDoctypeDeclHandler end);
1682: </pre>
1683: <p>Set both doctype handlers with one call.</p>
1684: </div>
1685:
1686: <div class="handler">
1687: <pre class="setter" id="XML_SetElementDeclHandler">
1688: void XMLCALL
1689: XML_SetElementDeclHandler(XML_Parser p,
1690: XML_ElementDeclHandler eldecl);
1691: </pre>
1692: <pre class="signature">
1693: typedef void
1694: (XMLCALL *XML_ElementDeclHandler)(void *userData,
1695: const XML_Char *name,
1696: XML_Content *model);
1697: </pre>
1698: <pre class="signature">
1699: enum XML_Content_Type {
1700: XML_CTYPE_EMPTY = 1,
1701: XML_CTYPE_ANY,
1702: XML_CTYPE_MIXED,
1703: XML_CTYPE_NAME,
1704: XML_CTYPE_CHOICE,
1705: XML_CTYPE_SEQ
1706: };
1707:
1708: enum XML_Content_Quant {
1709: XML_CQUANT_NONE,
1710: XML_CQUANT_OPT,
1711: XML_CQUANT_REP,
1712: XML_CQUANT_PLUS
1713: };
1714:
1715: typedef struct XML_cp XML_Content;
1716:
1717: struct XML_cp {
1718: enum XML_Content_Type type;
1719: enum XML_Content_Quant quant;
1720: const XML_Char * name;
1721: unsigned int numchildren;
1722: XML_Content * children;
1723: };
1724: </pre>
1725: <p>Sets a handler for element declarations in a DTD. The handler gets
1726: called with the name of the element in the declaration and a pointer
1727: to a structure that contains the element model. It is the
1728: application's responsibility to free this data structure using
1729: <code><a href="#XML_FreeContentModel"
1730: >XML_FreeContentModel</a></code>.</p>
1731:
1732: <p>The <code>model</code> argument is the root of a tree of
1733: <code>XML_Content</code> nodes. If <code>type</code> equals
1734: <code>XML_CTYPE_EMPTY</code> or <code>XML_CTYPE_ANY</code>, then
1735: <code>quant</code> will be <code>XML_CQUANT_NONE</code>, and the other
1736: fields will be zero or NULL. If <code>type</code> is
1737: <code>XML_CTYPE_MIXED</code>, then <code>quant</code> will be
1738: <code>XML_CQUANT_NONE</code> or <code>XML_CQUANT_REP</code> and
1739: <code>numchildren</code> will contain the number of elements that are
1740: allowed to be mixed in and <code>children</code> points to an array of
1741: <code>XML_Content</code> structures that will all have type
1742: XML_CTYPE_NAME with no quantification. Only the root node can be type
1743: <code>XML_CTYPE_EMPTY</code>, <code>XML_CTYPE_ANY</code>, or
1744: <code>XML_CTYPE_MIXED</code>.</p>
1745:
1746: <p>For type <code>XML_CTYPE_NAME</code>, the <code>name</code> field
1747: points to the name and the <code>numchildren</code> and
1748: <code>children</code> fields will be zero and NULL. The
1749: <code>quant</code> field will indicate any quantifiers placed on the
1750: name.</p>
1751:
1752: <p>Types <code>XML_CTYPE_CHOICE</code> and <code>XML_CTYPE_SEQ</code>
1753: indicate a choice or sequence respectively. The
1754: <code>numchildren</code> field indicates how many nodes in the choice
1755: or sequence and <code>children</code> points to the nodes.</p>
1756: </div>
1757:
1758: <div class="handler">
1759: <pre class="setter" id="XML_SetAttlistDeclHandler">
1760: void XMLCALL
1761: XML_SetAttlistDeclHandler(XML_Parser p,
1762: XML_AttlistDeclHandler attdecl);
1763: </pre>
1764: <pre class="signature">
1765: typedef void
1766: (XMLCALL *XML_AttlistDeclHandler)(void *userData,
1767: const XML_Char *elname,
1768: const XML_Char *attname,
1769: const XML_Char *att_type,
1770: const XML_Char *dflt,
1771: int isrequired);
1772: </pre>
1773: <p>Set a handler for attlist declarations in the DTD. This handler is
1774: called for <em>each</em> attribute. So a single attlist declaration
1775: with multiple attributes declared will generate multiple calls to this
1776: handler. The <code>elname</code> parameter returns the name of the
1777: element for which the attribute is being declared. The attribute name
1778: is in the <code>attname</code> parameter. The attribute type is in the
1779: <code>att_type</code> parameter. It is the string representing the
1780: type in the declaration with whitespace removed.</p>
1781:
1782: <p>The <code>dflt</code> parameter holds the default value. It will be
1783: NULL in the case of "#IMPLIED" or "#REQUIRED" attributes. You can
1784: distinguish these two cases by checking the <code>isrequired</code>
1785: parameter, which will be true in the case of "#REQUIRED" attributes.
1786: Attributes which are "#FIXED" will have also have a true
1787: <code>isrequired</code>, but they will have the non-NULL fixed value
1788: in the <code>dflt</code> parameter.</p>
1789: </div>
1790:
1791: <div class="handler">
1792: <pre class="setter" id="XML_SetEntityDeclHandler">
1793: void XMLCALL
1794: XML_SetEntityDeclHandler(XML_Parser p,
1795: XML_EntityDeclHandler handler);
1796: </pre>
1797: <pre class="signature">
1798: typedef void
1799: (XMLCALL *XML_EntityDeclHandler)(void *userData,
1800: const XML_Char *entityName,
1801: int is_parameter_entity,
1802: const XML_Char *value,
1803: int value_length,
1804: const XML_Char *base,
1805: const XML_Char *systemId,
1806: const XML_Char *publicId,
1807: const XML_Char *notationName);
1808: </pre>
1809: <p>Sets a handler that will be called for all entity declarations.
1810: The <code>is_parameter_entity</code> argument will be non-zero in the
1811: case of parameter entities and zero otherwise.</p>
1812:
1813: <p>For internal entities (<code><!ENTITY foo "bar"></code>),
1814: <code>value</code> will be non-NULL and <code>systemId</code>,
1815: <code>publicId</code>, and <code>notationName</code> will all be NULL.
1816: The value string is <em>not</em> NULL terminated; the length is
1817: provided in the <code>value_length</code> parameter. Do not use
1818: <code>value_length</code> to test for internal entities, since it is
1819: legal to have zero-length values. Instead check for whether or not
1820: <code>value</code> is NULL.</p> <p>The <code>notationName</code>
1821: argument will have a non-NULL value only for unparsed entity
1822: declarations.</p>
1823: </div>
1824:
1825: <div class="handler">
1826: <pre class="setter" id="XML_SetUnparsedEntityDeclHandler">
1827: void XMLCALL
1828: XML_SetUnparsedEntityDeclHandler(XML_Parser p,
1829: XML_UnparsedEntityDeclHandler h)
1830: </pre>
1831: <pre class="signature">
1832: typedef void
1833: (XMLCALL *XML_UnparsedEntityDeclHandler)(void *userData,
1834: const XML_Char *entityName,
1835: const XML_Char *base,
1836: const XML_Char *systemId,
1837: const XML_Char *publicId,
1838: const XML_Char *notationName);
1839: </pre>
1840: <p>Set a handler that receives declarations of unparsed entities. These
1841: are entity declarations that have a notation (NDATA) field:</p>
1842:
1843: <div id="eg"><pre>
1844: <!ENTITY logo SYSTEM "images/logo.gif" NDATA gif>
1845: </pre></div>
1846: <p>This handler is obsolete and is provided for backwards
1847: compatibility. Use instead <a href= "#XML_SetEntityDeclHandler"
1848: >XML_SetEntityDeclHandler</a>.</p>
1849: </div>
1850:
1851: <div class="handler">
1852: <pre class="setter" id="XML_SetNotationDeclHandler">
1853: void XMLCALL
1854: XML_SetNotationDeclHandler(XML_Parser p,
1855: XML_NotationDeclHandler h)
1856: </pre>
1857: <pre class="signature">
1858: typedef void
1859: (XMLCALL *XML_NotationDeclHandler)(void *userData,
1860: const XML_Char *notationName,
1861: const XML_Char *base,
1862: const XML_Char *systemId,
1863: const XML_Char *publicId);
1864: </pre>
1865: <p>Set a handler that receives notation declarations.</p>
1866: </div>
1867:
1868: <div class="handler">
1869: <pre class="setter" id="XML_SetNotStandaloneHandler">
1870: void XMLCALL
1871: XML_SetNotStandaloneHandler(XML_Parser p,
1872: XML_NotStandaloneHandler h)
1873: </pre>
1874: <pre class="signature">
1875: typedef int
1876: (XMLCALL *XML_NotStandaloneHandler)(void *userData);
1877: </pre>
1878: <p>Set a handler that is called if the document is not "standalone".
1879: This happens when there is an external subset or a reference to a
1880: parameter entity, but does not have standalone set to "yes" in an XML
1881: declaration. If this handler returns <code>XML_STATUS_ERROR</code>,
1882: then the parser will throw an <code>XML_ERROR_NOT_STANDALONE</code>
1883: error.</p>
1884: </div>
1885:
1886: <h3><a name="position">Parse position and error reporting functions</a></h3>
1887:
1888: <p>These are the functions you'll want to call when the parse
1889: functions return <code>XML_STATUS_ERROR</code> (a parse error has
1890: occurred), although the position reporting functions are useful outside
1891: of errors. The position reported is the byte position (in the original
1892: document or entity encoding) of the first of the sequence of
1893: characters that generated the current event (or the error that caused
1894: the parse functions to return <code>XML_STATUS_ERROR</code>.) The
1895: exceptions are callbacks trigged by declarations in the document
1896: prologue, in which case they exact position reported is somewhere in the
1897: relevant markup, but not necessarily as meaningful as for other
1898: events.</p>
1899:
1900: <p>The position reporting functions are accurate only outside of the
1901: DTD. In other words, they usually return bogus information when
1902: called from within a DTD declaration handler.</p>
1903:
1904: <pre class="fcndec" id="XML_GetErrorCode">
1905: enum XML_Error XMLCALL
1906: XML_GetErrorCode(XML_Parser p);
1907: </pre>
1908: <div class="fcndef">
1909: Return what type of error has occurred.
1910: </div>
1911:
1912: <pre class="fcndec" id="XML_ErrorString">
1913: const XML_LChar * XMLCALL
1914: XML_ErrorString(enum XML_Error code);
1915: </pre>
1916: <div class="fcndef">
1917: Return a string describing the error corresponding to code.
1918: The code should be one of the enums that can be returned from
1919: <code><a href= "#XML_GetErrorCode" >XML_GetErrorCode</a></code>.
1920: </div>
1921:
1922: <pre class="fcndec" id="XML_GetCurrentByteIndex">
1923: XML_Index XMLCALL
1924: XML_GetCurrentByteIndex(XML_Parser p);
1925: </pre>
1926: <div class="fcndef">
1927: Return the byte offset of the position. This always corresponds to
1928: the values returned by <code><a href= "#XML_GetCurrentLineNumber"
1929: >XML_GetCurrentLineNumber</a></code> and <code><a href=
1930: "#XML_GetCurrentColumnNumber" >XML_GetCurrentColumnNumber</a></code>.
1931: </div>
1932:
1933: <pre class="fcndec" id="XML_GetCurrentLineNumber">
1934: XML_Size XMLCALL
1935: XML_GetCurrentLineNumber(XML_Parser p);
1936: </pre>
1937: <div class="fcndef">
1938: Return the line number of the position. The first line is reported as
1939: <code>1</code>.
1940: </div>
1941:
1942: <pre class="fcndec" id="XML_GetCurrentColumnNumber">
1943: XML_Size XMLCALL
1944: XML_GetCurrentColumnNumber(XML_Parser p);
1945: </pre>
1946: <div class="fcndef">
1947: Return the offset, from the beginning of the current line, of
1948: the position.
1949: </div>
1950:
1951: <pre class="fcndec" id="XML_GetCurrentByteCount">
1952: int XMLCALL
1953: XML_GetCurrentByteCount(XML_Parser p);
1954: </pre>
1955: <div class="fcndef">
1956: Return the number of bytes in the current event. Returns
1957: <code>0</code> if the event is inside a reference to an internal
1958: entity and for the end-tag event for empty element tags (the later can
1959: be used to distinguish empty-element tags from empty elements using
1960: separate start and end tags).
1961: </div>
1962:
1963: <pre class="fcndec" id="XML_GetInputContext">
1964: const char * XMLCALL
1965: XML_GetInputContext(XML_Parser p,
1966: int *offset,
1967: int *size);
1968: </pre>
1969: <div class="fcndef">
1970:
1971: <p>Returns the parser's input buffer, sets the integer pointed at by
1972: <code>offset</code> to the offset within this buffer of the current
1973: parse position, and set the integer pointed at by <code>size</code> to
1974: the size of the returned buffer.</p>
1975:
1976: <p>This should only be called from within a handler during an active
1977: parse and the returned buffer should only be referred to from within
1978: the handler that made the call. This input buffer contains the
1979: untranslated bytes of the input.</p>
1980:
1981: <p>Only a limited amount of context is kept, so if the event
1982: triggering a call spans over a very large amount of input, the actual
1983: parse position may be before the beginning of the buffer.</p>
1984:
1985: <p>If <code>XML_CONTEXT_BYTES</code> is not defined, this will always
1986: return NULL.</p>
1987: </div>
1988:
1989: <h3><a name="miscellaneous">Miscellaneous functions</a></h3>
1990:
1991: <p>The functions in this section either obtain state information from
1992: the parser or can be used to dynamicly set parser options.</p>
1993:
1994: <pre class="fcndec" id="XML_SetUserData">
1995: void XMLCALL
1996: XML_SetUserData(XML_Parser p,
1997: void *userData);
1998: </pre>
1999: <div class="fcndef">
2000: This sets the user data pointer that gets passed to handlers. It
2001: overwrites any previous value for this pointer. Note that the
2002: application is responsible for freeing the memory associated with
2003: <code>userData</code> when it is finished with the parser. So if you
2004: call this when there's already a pointer there, and you haven't freed
2005: the memory associated with it, then you've probably just leaked
2006: memory.
2007: </div>
2008:
2009: <pre class="fcndec" id="XML_GetUserData">
2010: void * XMLCALL
2011: XML_GetUserData(XML_Parser p);
2012: </pre>
2013: <div class="fcndef">
2014: This returns the user data pointer that gets passed to handlers.
2015: It is actually implemented as a macro.
2016: </div>
2017:
2018: <pre class="fcndec" id="XML_UseParserAsHandlerArg">
2019: void XMLCALL
2020: XML_UseParserAsHandlerArg(XML_Parser p);
2021: </pre>
2022: <div class="fcndef">
2023: After this is called, handlers receive the parser in their
2024: <code>userData</code> arguments. The user data can still be obtained
2025: using the <code><a href= "#XML_GetUserData"
2026: >XML_GetUserData</a></code> function.
2027: </div>
2028:
2029: <pre class="fcndec" id="XML_SetBase">
2030: enum XML_Status XMLCALL
2031: XML_SetBase(XML_Parser p,
2032: const XML_Char *base);
2033: </pre>
2034: <div class="fcndef">
2035: Set the base to be used for resolving relative URIs in system
2036: identifiers. The return value is <code>XML_STATUS_ERROR</code> if
2037: there's no memory to store base, otherwise it's
2038: <code>XML_STATUS_OK</code>.
2039: </div>
2040:
2041: <pre class="fcndec" id="XML_GetBase">
2042: const XML_Char * XMLCALL
2043: XML_GetBase(XML_Parser p);
2044: </pre>
2045: <div class="fcndef">
2046: Return the base for resolving relative URIs.
2047: </div>
2048:
2049: <pre class="fcndec" id="XML_GetSpecifiedAttributeCount">
2050: int XMLCALL
2051: XML_GetSpecifiedAttributeCount(XML_Parser p);
2052: </pre>
2053: <div class="fcndef">
2054: When attributes are reported to the start handler in the atts vector,
2055: attributes that were explicitly set in the element occur before any
2056: attributes that receive their value from default information in an
2057: ATTLIST declaration. This function returns the number of attributes
2058: that were explicitly set times two, thus giving the offset in the
2059: <code>atts</code> array passed to the start tag handler of the first
2060: attribute set due to defaults. It supplies information for the last
2061: call to a start handler. If called inside a start handler, then that
2062: means the current call.
2063: </div>
2064:
2065: <pre class="fcndec" id="XML_GetIdAttributeIndex">
2066: int XMLCALL
2067: XML_GetIdAttributeIndex(XML_Parser p);
2068: </pre>
2069: <div class="fcndef">
2070: Returns the index of the ID attribute passed in the atts array in the
2071: last call to <code><a href= "#XML_StartElementHandler"
2072: >XML_StartElementHandler</a></code>, or -1 if there is no ID
2073: attribute. If called inside a start handler, then that means the
2074: current call.
2075: </div>
2076:
2077: <pre class="fcndec" id="XML_SetEncoding">
2078: enum XML_Status XMLCALL
2079: XML_SetEncoding(XML_Parser p,
2080: const XML_Char *encoding);
2081: </pre>
2082: <div class="fcndef">
2083: Set the encoding to be used by the parser. It is equivalent to
2084: passing a non-null encoding argument to the parser creation functions.
2085: It must not be called after <code><a href= "#XML_Parse"
2086: >XML_Parse</a></code> or <code><a href= "#XML_ParseBuffer"
2087: >XML_ParseBuffer</a></code> have been called on the given parser.
2088: Returns <code>XML_STATUS_OK</code> on success or
2089: <code>XML_STATUS_ERROR</code> on error.
2090: </div>
2091:
2092: <pre class="fcndec" id="XML_SetParamEntityParsing">
2093: int XMLCALL
2094: XML_SetParamEntityParsing(XML_Parser p,
2095: enum XML_ParamEntityParsing code);
2096: </pre>
2097: <div class="fcndef">
2098: This enables parsing of parameter entities, including the external
2099: parameter entity that is the external DTD subset, according to
2100: <code>code</code>.
2101: The choices for <code>code</code> are:
2102: <ul>
2103: <li><code>XML_PARAM_ENTITY_PARSING_NEVER</code></li>
2104: <li><code>XML_PARAM_ENTITY_PARSING_UNLESS_STANDALONE</code></li>
2105: <li><code>XML_PARAM_ENTITY_PARSING_ALWAYS</code></li>
2106: </ul>
2107: </div>
2108:
2109: <pre class="fcndec" id="XML_UseForeignDTD">
2110: enum XML_Error XMLCALL
2111: XML_UseForeignDTD(XML_Parser parser, XML_Bool useDTD);
2112: </pre>
2113: <div class="fcndef">
2114: <p>This function allows an application to provide an external subset
2115: for the document type declaration for documents which do not specify
2116: an external subset of their own. For documents which specify an
2117: external subset in their DOCTYPE declaration, the application-provided
2118: subset will be ignored. If the document does not contain a DOCTYPE
2119: declaration at all and <code>useDTD</code> is true, the
2120: application-provided subset will be parsed, but the
2121: <code>startDoctypeDeclHandler</code> and
2122: <code>endDoctypeDeclHandler</code> functions, if set, will not be
2123: called. The setting of parameter entity parsing, controlled using
2124: <code><a href= "#XML_SetParamEntityParsing"
2125: >XML_SetParamEntityParsing</a></code>, will be honored.</p>
2126:
2127: <p>The application-provided external subset is read by calling the
2128: external entity reference handler set via <code><a href=
2129: "#XML_SetExternalEntityRefHandler"
2130: >XML_SetExternalEntityRefHandler</a></code> with both
2131: <code>publicId</code> and <code>systemId</code> set to NULL.</p>
2132:
2133: <p>If this function is called after parsing has begun, it returns
2134: <code>XML_ERROR_CANT_CHANGE_FEATURE_ONCE_PARSING</code> and ignores
2135: <code>useDTD</code>. If called when Expat has been compiled without
2136: DTD support, it returns
2137: <code>XML_ERROR_FEATURE_REQUIRES_XML_DTD</code>. Otherwise, it
2138: returns <code>XML_ERROR_NONE</code>.</p>
2139:
2140: <p><b>Note:</b> For the purpose of checking WFC: Entity Declared, passing
2141: <code>useDTD == XML_TRUE</code> will make the parser behave as if
2142: the document had a DTD with an external subset. This holds true even if
2143: the external entity reference handler returns without action.</p>
2144: </div>
2145:
2146: <pre class="fcndec" id="XML_SetReturnNSTriplet">
2147: void XMLCALL
2148: XML_SetReturnNSTriplet(XML_Parser parser,
2149: int do_nst);
2150: </pre>
2151: <div class="fcndef">
2152: <p>
2153: This function only has an effect when using a parser created with
2154: <code><a href= "#XML_ParserCreateNS" >XML_ParserCreateNS</a></code>,
2155: i.e. when namespace processing is in effect. The <code>do_nst</code>
2156: sets whether or not prefixes are returned with names qualified with a
2157: namespace prefix. If this function is called with <code>do_nst</code>
2158: non-zero, then afterwards namespace qualified names (that is qualified
2159: with a prefix as opposed to belonging to a default namespace) are
2160: returned as a triplet with the three parts separated by the namespace
2161: separator specified when the parser was created. The order of
2162: returned parts is URI, local name, and prefix.</p> <p>If
2163: <code>do_nst</code> is zero, then namespaces are reported in the
2164: default manner, URI then local_name separated by the namespace
2165: separator.</p>
2166: </div>
2167:
2168: <pre class="fcndec" id="XML_DefaultCurrent">
2169: void XMLCALL
2170: XML_DefaultCurrent(XML_Parser parser);
2171: </pre>
2172: <div class="fcndef">
2173: This can be called within a handler for a start element, end element,
2174: processing instruction or character data. It causes the corresponding
2175: markup to be passed to the default handler set by <code><a
2176: href="#XML_SetDefaultHandler" >XML_SetDefaultHandler</a></code> or
2177: <code><a href="#XML_SetDefaultHandlerExpand"
2178: >XML_SetDefaultHandlerExpand</a></code>. It does nothing if there is
2179: not a default handler.
2180: </div>
2181:
2182: <pre class="fcndec" id="XML_ExpatVersion">
2183: XML_LChar * XMLCALL
2184: XML_ExpatVersion();
2185: </pre>
2186: <div class="fcndef">
2187: Return the library version as a string (e.g. <code>"expat_1.95.1"</code>).
2188: </div>
2189:
2190: <pre class="fcndec" id="XML_ExpatVersionInfo">
2191: struct XML_Expat_Version XMLCALL
2192: XML_ExpatVersionInfo();
2193: </pre>
2194: <pre class="signature">
2195: typedef struct {
2196: int major;
2197: int minor;
2198: int micro;
2199: } XML_Expat_Version;
2200: </pre>
2201: <div class="fcndef">
2202: Return the library version information as a structure.
2203: Some macros are also defined that support compile-time tests of the
2204: library version:
2205: <ul>
2206: <li><code>XML_MAJOR_VERSION</code></li>
2207: <li><code>XML_MINOR_VERSION</code></li>
2208: <li><code>XML_MICRO_VERSION</code></li>
2209: </ul>
2210: Testing these constants is currently the best way to determine if
2211: particular parts of the Expat API are available.
2212: </div>
2213:
2214: <pre class="fcndec" id="XML_GetFeatureList">
2215: const XML_Feature * XMLCALL
2216: XML_GetFeatureList();
2217: </pre>
2218: <pre class="signature">
2219: enum XML_FeatureEnum {
2220: XML_FEATURE_END = 0,
2221: XML_FEATURE_UNICODE,
2222: XML_FEATURE_UNICODE_WCHAR_T,
2223: XML_FEATURE_DTD,
2224: XML_FEATURE_CONTEXT_BYTES,
2225: XML_FEATURE_MIN_SIZE,
2226: XML_FEATURE_SIZEOF_XML_CHAR,
2227: XML_FEATURE_SIZEOF_XML_LCHAR,
2228: XML_FEATURE_NS,
2229: XML_FEATURE_LARGE_SIZE
2230: };
2231:
2232: typedef struct {
2233: enum XML_FeatureEnum feature;
2234: XML_LChar *name;
2235: long int value;
2236: } XML_Feature;
2237: </pre>
2238: <div class="fcndef">
2239: <p>Returns a list of "feature" records, providing details on how
2240: Expat was configured at compile time. Most applications should not
2241: need to worry about this, but this information is otherwise not
2242: available from Expat. This function allows code that does need to
2243: check these features to do so at runtime.</p>
2244:
2245: <p>The return value is an array of <code>XML_Feature</code>,
2246: terminated by a record with a <code>feature</code> of
2247: <code>XML_FEATURE_END</code> and <code>name</code> of NULL,
2248: identifying the feature-test macros Expat was compiled with. Since an
2249: application that requires this kind of information needs to determine
2250: the type of character the <code>name</code> points to, records for the
2251: <code>XML_FEATURE_SIZEOF_XML_CHAR</code> and
2252: <code>XML_FEATURE_SIZEOF_XML_LCHAR</code> will be located at the
2253: beginning of the list, followed by <code>XML_FEATURE_UNICODE</code>
2254: and <code>XML_FEATURE_UNICODE_WCHAR_T</code>, if they are present at
2255: all.</p>
2256:
2257: <p>Some features have an associated value. If there isn't an
2258: associated value, the <code>value</code> field is set to 0. At this
2259: time, the following features have been defined to have values:</p>
2260:
2261: <dl>
2262: <dt><code>XML_FEATURE_SIZEOF_XML_CHAR</code></dt>
2263: <dd>The number of bytes occupied by one <code>XML_Char</code>
2264: character.</dd>
2265: <dt><code>XML_FEATURE_SIZEOF_XML_LCHAR</code></dt>
2266: <dd>The number of bytes occupied by one <code>XML_LChar</code>
2267: character.</dd>
2268: <dt><code>XML_FEATURE_CONTEXT_BYTES</code></dt>
2269: <dd>The maximum number of characters of context which can be
2270: reported by <code><a href= "#XML_GetInputContext"
2271: >XML_GetInputContext</a></code>.</dd>
2272: </dl>
2273: </div>
2274:
2275: <pre class="fcndec" id="XML_FreeContentModel">
2276: void XMLCALL
2277: XML_FreeContentModel(XML_Parser parser, XML_Content *model);
2278: </pre>
2279: <div class="fcndef">
2280: Function to deallocate the <code>model</code> argument passed to the
2281: <code>XML_ElementDeclHandler</code> callback set using <code><a
2282: href="#XML_SetElementDeclHandler" >XML_ElementDeclHandler</a></code>.
2283: This function should not be used for any other purpose.
2284: </div>
2285:
2286: <p>The following functions allow external code to share the memory
2287: allocator an <code>XML_Parser</code> has been configured to use. This
2288: is especially useful for third-party libraries that interact with a
2289: parser object created by application code, or heavily layered
2290: applications. This can be essential when using dynamically loaded
2291: libraries which use different C standard libraries (this can happen on
2292: Windows, at least).</p>
2293:
2294: <pre class="fcndec" id="XML_MemMalloc">
2295: void * XMLCALL
2296: XML_MemMalloc(XML_Parser parser, size_t size);
2297: </pre>
2298: <div class="fcndef">
2299: Allocate <code>size</code> bytes of memory using the allocator the
2300: <code>parser</code> object has been configured to use. Returns a
2301: pointer to the memory or NULL on failure. Memory allocated in this
2302: way must be freed using <code><a href="#XML_MemFree"
2303: >XML_MemFree</a></code>.
2304: </div>
2305:
2306: <pre class="fcndec" id="XML_MemRealloc">
2307: void * XMLCALL
2308: XML_MemRealloc(XML_Parser parser, void *ptr, size_t size);
2309: </pre>
2310: <div class="fcndef">
2311: Allocate <code>size</code> bytes of memory using the allocator the
2312: <code>parser</code> object has been configured to use.
2313: <code>ptr</code> must point to a block of memory allocated by <code><a
2314: href="#XML_MemMalloc" >XML_MemMalloc</a></code> or
2315: <code>XML_MemRealloc</code>, or be NULL. This function tries to
2316: expand the block pointed to by <code>ptr</code> if possible. Returns
2317: a pointer to the memory or NULL on failure. On success, the original
2318: block has either been expanded or freed. On failure, the original
2319: block has not been freed; the caller is responsible for freeing the
2320: original block. Memory allocated in this way must be freed using
2321: <code><a href="#XML_MemFree"
2322: >XML_MemFree</a></code>.
2323: </div>
2324:
2325: <pre class="fcndec" id="XML_MemFree">
2326: void XMLCALL
2327: XML_MemFree(XML_Parser parser, void *ptr);
2328: </pre>
2329: <div class="fcndef">
2330: Free a block of memory pointed to by <code>ptr</code>. The block must
2331: have been allocated by <code><a href="#XML_MemMalloc"
2332: >XML_MemMalloc</a></code> or <code>XML_MemRealloc</code>, or be NULL.
2333: </div>
2334:
2335: <hr />
2336: <p><a href="http://validator.w3.org/check/referer"><img
2337: src="valid-xhtml10.png" alt="Valid XHTML 1.0!"
2338: height="31" width="88" class="noborder" /></a></p>
2339: </div>
2340: </body>
2341: </html>
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