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10: <title>Expat XML Parser</title>
11: <meta name="author" content="Clark Cooper, coopercc@netheaven.com" />
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16: <table cellspacing="0" cellpadding="0" width="100%">
17: <tr>
18: <td class="corner"><img src="expat.png" alt="(Expat logo)" /></td>
19: <td class="banner"><h1>The Expat XML Parser</h1></td>
20: </tr>
21: <tr>
22: <td class="releaseno">Release 2.0.1</td>
23: <td></td>
24: </tr>
25: </table>
26: <div class="content">
27:
28: <p>Expat is a library, written in C, for parsing XML documents. It's
29: the underlying XML parser for the open source Mozilla project, Perl's
30: <code>XML::Parser</code>, Python's <code>xml.parsers.expat</code>, and
31: other open-source XML parsers.</p>
32:
33: <p>This library is the creation of James Clark, who's also given us
34: groff (an nroff look-alike), Jade (an implemention of ISO's DSSSL
35: stylesheet language for SGML), XP (a Java XML parser package), XT (a
36: Java XSL engine). James was also the technical lead on the XML
37: Working Group at W3C that produced the XML specification.</p>
38:
39: <p>This is free software, licensed under the <a
40: href="../COPYING">MIT/X Consortium license</a>. You may download it
41: from <a href="http://www.libexpat.org/">the Expat home page</a>.
42: </p>
43:
44: <p>The bulk of this document was originally commissioned as an article
45: by <a href="http://www.xml.com/">XML.com</a>. They graciously allowed
46: Clark Cooper to retain copyright and to distribute it with Expat.
47: This version has been substantially extended to include documentation
48: on features which have been added since the original article was
49: published, and additional information on using the original
50: interface.</p>
51:
52: <hr />
53: <h2>Table of Contents</h2>
54: <ul>
55: <li><a href="#overview">Overview</a></li>
56: <li><a href="#building">Building and Installing</a></li>
57: <li><a href="#using">Using Expat</a></li>
58: <li><a href="#reference">Reference</a>
59: <ul>
60: <li><a href="#creation">Parser Creation Functions</a>
61: <ul>
62: <li><a href="#XML_ParserCreate">XML_ParserCreate</a></li>
63: <li><a href="#XML_ParserCreateNS">XML_ParserCreateNS</a></li>
64: <li><a href="#XML_ParserCreate_MM">XML_ParserCreate_MM</a></li>
65: <li><a href="#XML_ExternalEntityParserCreate">XML_ExternalEntityParserCreate</a></li>
66: <li><a href="#XML_ParserFree">XML_ParserFree</a></li>
67: <li><a href="#XML_ParserReset">XML_ParserReset</a></li>
68: </ul>
69: </li>
70: <li><a href="#parsing">Parsing Functions</a>
71: <ul>
72: <li><a href="#XML_Parse">XML_Parse</a></li>
73: <li><a href="#XML_ParseBuffer">XML_ParseBuffer</a></li>
74: <li><a href="#XML_GetBuffer">XML_GetBuffer</a></li>
75: <li><a href="#XML_StopParser">XML_StopParser</a></li>
76: <li><a href="#XML_ResumeParser">XML_ResumeParser</a></li>
77: <li><a href="#XML_GetParsingStatus">XML_GetParsingStatus</a></li>
78: </ul>
79: </li>
80: <li><a href="#setting">Handler Setting Functions</a>
81: <ul>
82: <li><a href="#XML_SetStartElementHandler">XML_SetStartElementHandler</a></li>
83: <li><a href="#XML_SetEndElementHandler">XML_SetEndElementHandler</a></li>
84: <li><a href="#XML_SetElementHandler">XML_SetElementHandler</a></li>
85: <li><a href="#XML_SetCharacterDataHandler">XML_SetCharacterDataHandler</a></li>
86: <li><a href="#XML_SetProcessingInstructionHandler">XML_SetProcessingInstructionHandler</a></li>
87: <li><a href="#XML_SetCommentHandler">XML_SetCommentHandler</a></li>
88: <li><a href="#XML_SetStartCdataSectionHandler">XML_SetStartCdataSectionHandler</a></li>
89: <li><a href="#XML_SetEndCdataSectionHandler">XML_SetEndCdataSectionHandler</a></li>
90: <li><a href="#XML_SetCdataSectionHandler">XML_SetCdataSectionHandler</a></li>
91: <li><a href="#XML_SetDefaultHandler">XML_SetDefaultHandler</a></li>
92: <li><a href="#XML_SetDefaultHandlerExpand">XML_SetDefaultHandlerExpand</a></li>
93: <li><a href="#XML_SetExternalEntityRefHandler">XML_SetExternalEntityRefHandler</a></li>
94: <li><a href="#XML_SetExternalEntityRefHandlerArg">XML_SetExternalEntityRefHandlerArg</a></li>
95: <li><a href="#XML_SetSkippedEntityHandler">XML_SetSkippedEntityHandler</a></li>
96: <li><a href="#XML_SetUnknownEncodingHandler">XML_SetUnknownEncodingHandler</a></li>
97: <li><a href="#XML_SetStartNamespaceDeclHandler">XML_SetStartNamespaceDeclHandler</a></li>
98: <li><a href="#XML_SetEndNamespaceDeclHandler">XML_SetEndNamespaceDeclHandler</a></li>
99: <li><a href="#XML_SetNamespaceDeclHandler">XML_SetNamespaceDeclHandler</a></li>
100: <li><a href="#XML_SetXmlDeclHandler">XML_SetXmlDeclHandler</a></li>
101: <li><a href="#XML_SetStartDoctypeDeclHandler">XML_SetStartDoctypeDeclHandler</a></li>
102: <li><a href="#XML_SetEndDoctypeDeclHandler">XML_SetEndDoctypeDeclHandler</a></li>
103: <li><a href="#XML_SetDoctypeDeclHandler">XML_SetDoctypeDeclHandler</a></li>
104: <li><a href="#XML_SetElementDeclHandler">XML_SetElementDeclHandler</a></li>
105: <li><a href="#XML_SetAttlistDeclHandler">XML_SetAttlistDeclHandler</a></li>
106: <li><a href="#XML_SetEntityDeclHandler">XML_SetEntityDeclHandler</a></li>
107: <li><a href="#XML_SetUnparsedEntityDeclHandler">XML_SetUnparsedEntityDeclHandler</a></li>
108: <li><a href="#XML_SetNotationDeclHandler">XML_SetNotationDeclHandler</a></li>
109: <li><a href="#XML_SetNotStandaloneHandler">XML_SetNotStandaloneHandler</a></li>
110: </ul>
111: </li>
112: <li><a href="#position">Parse Position and Error Reporting Functions</a>
113: <ul>
114: <li><a href="#XML_GetErrorCode">XML_GetErrorCode</a></li>
115: <li><a href="#XML_ErrorString">XML_ErrorString</a></li>
116: <li><a href="#XML_GetCurrentByteIndex">XML_GetCurrentByteIndex</a></li>
117: <li><a href="#XML_GetCurrentLineNumber">XML_GetCurrentLineNumber</a></li>
118: <li><a href="#XML_GetCurrentColumnNumber">XML_GetCurrentColumnNumber</a></li>
119: <li><a href="#XML_GetCurrentByteCount">XML_GetCurrentByteCount</a></li>
120: <li><a href="#XML_GetInputContext">XML_GetInputContext</a></li>
121: </ul>
122: </li>
123: <li><a href="#miscellaneous">Miscellaneous Functions</a>
124: <ul>
125: <li><a href="#XML_SetUserData">XML_SetUserData</a></li>
126: <li><a href="#XML_GetUserData">XML_GetUserData</a></li>
127: <li><a href="#XML_UseParserAsHandlerArg">XML_UseParserAsHandlerArg</a></li>
128: <li><a href="#XML_SetBase">XML_SetBase</a></li>
129: <li><a href="#XML_GetBase">XML_GetBase</a></li>
130: <li><a href="#XML_GetSpecifiedAttributeCount">XML_GetSpecifiedAttributeCount</a></li>
131: <li><a href="#XML_GetIdAttributeIndex">XML_GetIdAttributeIndex</a></li>
132: <li><a href="#XML_GetAttributeInfo">XML_GetAttributeInfo</a></li>
133: <li><a href="#XML_SetEncoding">XML_SetEncoding</a></li>
134: <li><a href="#XML_SetParamEntityParsing">XML_SetParamEntityParsing</a></li>
135: <li><a href="#XML_SetHashSalt">XML_SetHashSalt</a></li>
136: <li><a href="#XML_UseForeignDTD">XML_UseForeignDTD</a></li>
137: <li><a href="#XML_SetReturnNSTriplet">XML_SetReturnNSTriplet</a></li>
138: <li><a href="#XML_DefaultCurrent">XML_DefaultCurrent</a></li>
139: <li><a href="#XML_ExpatVersion">XML_ExpatVersion</a></li>
140: <li><a href="#XML_ExpatVersionInfo">XML_ExpatVersionInfo</a></li>
141: <li><a href="#XML_GetFeatureList">XML_GetFeatureList</a></li>
142: <li><a href="#XML_FreeContentModel">XML_FreeContentModel</a></li>
143: <li><a href="#XML_MemMalloc">XML_MemMalloc</a></li>
144: <li><a href="#XML_MemRealloc">XML_MemRealloc</a></li>
145: <li><a href="#XML_MemFree">XML_MemFree</a></li>
146: </ul>
147: </li>
148: </ul>
149: </li>
150: </ul>
151:
152: <hr />
153: <h2><a name="overview">Overview</a></h2>
154:
155: <p>Expat is a stream-oriented parser. You register callback (or
156: handler) functions with the parser and then start feeding it the
157: document. As the parser recognizes parts of the document, it will
158: call the appropriate handler for that part (if you've registered one.)
159: The document is fed to the parser in pieces, so you can start parsing
160: before you have all the document. This also allows you to parse really
161: huge documents that won't fit into memory.</p>
162:
163: <p>Expat can be intimidating due to the many kinds of handlers and
164: options you can set. But you only need to learn four functions in
165: order to do 90% of what you'll want to do with it:</p>
166:
167: <dl>
168:
169: <dt><code><a href= "#XML_ParserCreate"
170: >XML_ParserCreate</a></code></dt>
171: <dd>Create a new parser object.</dd>
172:
173: <dt><code><a href= "#XML_SetElementHandler"
174: >XML_SetElementHandler</a></code></dt>
175: <dd>Set handlers for start and end tags.</dd>
176:
177: <dt><code><a href= "#XML_SetCharacterDataHandler"
178: >XML_SetCharacterDataHandler</a></code></dt>
179: <dd>Set handler for text.</dd>
180:
181: <dt><code><a href= "#XML_Parse"
182: >XML_Parse</a></code></dt>
183: <dd>Pass a buffer full of document to the parser</dd>
184: </dl>
185:
186: <p>These functions and others are described in the <a
187: href="#reference">reference</a> part of this document. The reference
188: section also describes in detail the parameters passed to the
189: different types of handlers.</p>
190:
191: <p>Let's look at a very simple example program that only uses 3 of the
192: above functions (it doesn't need to set a character handler.) The
193: program <a href="../examples/outline.c">outline.c</a> prints an
194: element outline, indenting child elements to distinguish them from the
195: parent element that contains them. The start handler does all the
196: work. It prints two indenting spaces for every level of ancestor
197: elements, then it prints the element and attribute
198: information. Finally it increments the global <code>Depth</code>
199: variable.</p>
200:
201: <pre class="eg">
202: int Depth;
203:
204: void XMLCALL
205: start(void *data, const char *el, const char **attr) {
206: int i;
207:
208: for (i = 0; i < Depth; i++)
209: printf(" ");
210:
211: printf("%s", el);
212:
213: for (i = 0; attr[i]; i += 2) {
214: printf(" %s='%s'", attr[i], attr[i + 1]);
215: }
216:
217: printf("\n");
218: Depth++;
219: } /* End of start handler */
220: </pre>
221:
222: <p>The end tag simply does the bookkeeping work of decrementing
223: <code>Depth</code>.</p>
224: <pre class="eg">
225: void XMLCALL
226: end(void *data, const char *el) {
227: Depth--;
228: } /* End of end handler */
229: </pre>
230:
231: <p>Note the <code>XMLCALL</code> annotation used for the callbacks.
232: This is used to ensure that the Expat and the callbacks are using the
233: same calling convention in case the compiler options used for Expat
234: itself and the client code are different. Expat tries not to care
235: what the default calling convention is, though it may require that it
236: be compiled with a default convention of "cdecl" on some platforms.
237: For code which uses Expat, however, the calling convention is
238: specified by the <code>XMLCALL</code> annotation on most platforms;
239: callbacks should be defined using this annotation.</p>
240:
241: <p>The <code>XMLCALL</code> annotation was added in Expat 1.95.7, but
242: existing working Expat applications don't need to add it (since they
243: are already using the "cdecl" calling convention, or they wouldn't be
244: working). The annotation is only needed if the default calling
245: convention may be something other than "cdecl". To use the annotation
246: safely with older versions of Expat, you can conditionally define it
247: <em>after</em> including Expat's header file:</p>
248:
249: <pre class="eg">
250: #include <expat.h>
251:
252: #ifndef XMLCALL
253: #if defined(_MSC_EXTENSIONS) && !defined(__BEOS__) && !defined(__CYGWIN__)
254: #define XMLCALL __cdecl
255: #elif defined(__GNUC__)
256: #define XMLCALL __attribute__((cdecl))
257: #else
258: #define XMLCALL
259: #endif
260: #endif
261: </pre>
262:
263: <p>After creating the parser, the main program just has the job of
264: shoveling the document to the parser so that it can do its work.</p>
265:
266: <hr />
267: <h2><a name="building">Building and Installing Expat</a></h2>
268:
269: <p>The Expat distribution comes as a compressed (with GNU gzip) tar
270: file. You may download the latest version from <a href=
271: "http://sourceforge.net/projects/expat/" >Source Forge</a>. After
272: unpacking this, cd into the directory. Then follow either the Win32
273: directions or Unix directions below.</p>
274:
275: <h3>Building under Win32</h3>
276:
277: <p>If you're using the GNU compiler under cygwin, follow the Unix
278: directions in the next section. Otherwise if you have Microsoft's
279: Developer Studio installed, then from Windows Explorer double-click on
280: "expat.dsp" in the lib directory and build and install in the usual
281: manner.</p>
282:
283: <p>Alternatively, you may download the Win32 binary package that
284: contains the "expat.h" include file and a pre-built DLL.</p>
285:
286: <h3>Building under Unix (or GNU)</h3>
287:
288: <p>First you'll need to run the configure shell script in order to
289: configure the Makefiles and headers for your system.</p>
290:
291: <p>If you're happy with all the defaults that configure picks for you,
292: and you have permission on your system to install into /usr/local, you
293: can install Expat with this sequence of commands:</p>
294:
295: <pre class="eg">
296: ./configure
297: make
298: make install
299: </pre>
300:
301: <p>There are some options that you can provide to this script, but the
302: only one we'll mention here is the <code>--prefix</code> option. You
303: can find out all the options available by running configure with just
304: the <code>--help</code> option.</p>
305:
306: <p>By default, the configure script sets things up so that the library
307: gets installed in <code>/usr/local/lib</code> and the associated
308: header file in <code>/usr/local/include</code>. But if you were to
309: give the option, <code>--prefix=/home/me/mystuff</code>, then the
310: library and header would get installed in
311: <code>/home/me/mystuff/lib</code> and
312: <code>/home/me/mystuff/include</code> respectively.</p>
313:
314: <h3>Configuring Expat Using the Pre-Processor</h3>
315:
316: <p>Expat's feature set can be configured using a small number of
317: pre-processor definitions. The definition of this symbols does not
318: affect the set of entry points for Expat, only the behavior of the API
319: and the definition of character types in the case of
320: <code>XML_UNICODE_WCHAR_T</code>. The symbols are:</p>
321:
322: <dl class="cpp-symbols">
323: <dt>XML_DTD</dt>
324: <dd>Include support for using and reporting DTD-based content. If
325: this is defined, default attribute values from an external DTD subset
326: are reported and attribute value normalization occurs based on the
327: type of attributes defined in the external subset. Without
328: this, Expat has a smaller memory footprint and can be faster, but will
329: not load external entities or process conditional sections. This does
330: not affect the set of functions available in the API.</dd>
331:
332: <dt>XML_NS</dt>
333: <dd>When defined, support for the <cite><a href=
334: "http://www.w3.org/TR/REC-xml-names/" >Namespaces in XML</a></cite>
335: specification is included.</dd>
336:
337: <dt>XML_UNICODE</dt>
338: <dd>When defined, character data reported to the application is
339: encoded in UTF-16 using wide characters of the type
340: <code>XML_Char</code>. This is implied if
341: <code>XML_UNICODE_WCHAR_T</code> is defined.</dd>
342:
343: <dt>XML_UNICODE_WCHAR_T</dt>
344: <dd>If defined, causes the <code>XML_Char</code> character type to be
345: defined using the <code>wchar_t</code> type; otherwise, <code>unsigned
346: short</code> is used. Defining this implies
347: <code>XML_UNICODE</code>.</dd>
348:
349: <dt>XML_LARGE_SIZE</dt>
350: <dd>If defined, causes the <code>XML_Size</code> and <code>XML_Index</code>
351: integer types to be at least 64 bits in size. This is intended to support
352: processing of very large input streams, where the return values of
353: <code><a href="#XML_GetCurrentByteIndex" >XML_GetCurrentByteIndex</a></code>,
354: <code><a href="#XML_GetCurrentLineNumber" >XML_GetCurrentLineNumber</a></code> and
355: <code><a href="#XML_GetCurrentColumnNumber" >XML_GetCurrentColumnNumber</a></code>
356: could overflow. It may not be supported by all compilers, and is turned
357: off by default.</dd>
358:
359: <dt>XML_CONTEXT_BYTES</dt>
360: <dd>The number of input bytes of markup context which the parser will
361: ensure are available for reporting via <code><a href=
362: "#XML_GetInputContext" >XML_GetInputContext</a></code>. This is
363: normally set to 1024, and must be set to a positive interger. If this
364: is not defined, the input context will not be available and <code><a
365: href= "#XML_GetInputContext" >XML_GetInputContext</a></code> will
366: always report NULL. Without this, Expat has a smaller memory
367: footprint and can be faster.</dd>
368:
369: <dt>XML_STATIC</dt>
370: <dd>On Windows, this should be set if Expat is going to be linked
371: statically with the code that calls it; this is required to get all
372: the right MSVC magic annotations correct. This is ignored on other
373: platforms.</dd>
374:
375: <dt>XML_ATTR_INFO</dt>
376: <dd>If defined, makes the the additional function <code><a href=
377: "#XML_GetAttributeInfo" >XML_GetAttributeInfo</a></code> available
378: for reporting attribute byte offsets.</dd>
379: </dl>
380:
381: <hr />
382: <h2><a name="using">Using Expat</a></h2>
383:
384: <h3>Compiling and Linking Against Expat</h3>
385:
386: <p>Unless you installed Expat in a location not expected by your
387: compiler and linker, all you have to do to use Expat in your programs
388: is to include the Expat header (<code>#include <expat.h></code>)
389: in your files that make calls to it and to tell the linker that it
390: needs to link against the Expat library. On Unix systems, this would
391: usually be done with the <code>-lexpat</code> argument. Otherwise,
392: you'll need to tell the compiler where to look for the Expat header
393: and the linker where to find the Expat library. You may also need to
394: take steps to tell the operating system where to find this library at
395: run time.</p>
396:
397: <p>On a Unix-based system, here's what a Makefile might look like when
398: Expat is installed in a standard location:</p>
399:
400: <pre class="eg">
401: CC=cc
402: LDFLAGS=
403: LIBS= -lexpat
404: xmlapp: xmlapp.o
405: $(CC) $(LDFLAGS) -o xmlapp xmlapp.o $(LIBS)
406: </pre>
407:
408: <p>If you installed Expat in, say, <code>/home/me/mystuff</code>, then
409: the Makefile would look like this:</p>
410:
411: <pre class="eg">
412: CC=cc
413: CFLAGS= -I/home/me/mystuff/include
414: LDFLAGS=
415: LIBS= -L/home/me/mystuff/lib -lexpat
416: xmlapp: xmlapp.o
417: $(CC) $(LDFLAGS) -o xmlapp xmlapp.o $(LIBS)
418: </pre>
419:
420: <p>You'd also have to set the environment variable
421: <code>LD_LIBRARY_PATH</code> to <code>/home/me/mystuff/lib</code> (or
422: to <code>${LD_LIBRARY_PATH}:/home/me/mystuff/lib</code> if
423: LD_LIBRARY_PATH already has some directories in it) in order to run
424: your application.</p>
425:
426: <h3>Expat Basics</h3>
427:
428: <p>As we saw in the example in the overview, the first step in parsing
429: an XML document with Expat is to create a parser object. There are <a
430: href="#creation">three functions</a> in the Expat API for creating a
431: parser object. However, only two of these (<code><a href=
432: "#XML_ParserCreate" >XML_ParserCreate</a></code> and <code><a href=
433: "#XML_ParserCreateNS" >XML_ParserCreateNS</a></code>) can be used for
434: constructing a parser for a top-level document. The object returned
435: by these functions is an opaque pointer (i.e. "expat.h" declares it as
436: void *) to data with further internal structure. In order to free the
437: memory associated with this object you must call <code><a href=
438: "#XML_ParserFree" >XML_ParserFree</a></code>. Note that if you have
439: provided any <a href="#userdata">user data</a> that gets stored in the
440: parser, then your application is responsible for freeing it prior to
441: calling <code>XML_ParserFree</code>.</p>
442:
443: <p>The objects returned by the parser creation functions are good for
444: parsing only one XML document or external parsed entity. If your
445: application needs to parse many XML documents, then it needs to create
446: a parser object for each one. The best way to deal with this is to
447: create a higher level object that contains all the default
448: initialization you want for your parser objects.</p>
449:
450: <p>Walking through a document hierarchy with a stream oriented parser
451: will require a good stack mechanism in order to keep track of current
452: context. For instance, to answer the simple question, "What element
453: does this text belong to?" requires a stack, since the parser may have
454: descended into other elements that are children of the current one and
455: has encountered this text on the way out.</p>
456:
457: <p>The things you're likely to want to keep on a stack are the
458: currently opened element and it's attributes. You push this
459: information onto the stack in the start handler and you pop it off in
460: the end handler.</p>
461:
462: <p>For some tasks, it is sufficient to just keep information on what
463: the depth of the stack is (or would be if you had one.) The outline
464: program shown above presents one example. Another such task would be
465: skipping over a complete element. When you see the start tag for the
466: element you want to skip, you set a skip flag and record the depth at
467: which the element started. When the end tag handler encounters the
468: same depth, the skipped element has ended and the flag may be
469: cleared. If you follow the convention that the root element starts at
470: 1, then you can use the same variable for skip flag and skip
471: depth.</p>
472:
473: <pre class="eg">
474: void
475: init_info(Parseinfo *info) {
476: info->skip = 0;
477: info->depth = 1;
478: /* Other initializations here */
479: } /* End of init_info */
480:
481: void XMLCALL
482: rawstart(void *data, const char *el, const char **attr) {
483: Parseinfo *inf = (Parseinfo *) data;
484:
485: if (! inf->skip) {
486: if (should_skip(inf, el, attr)) {
487: inf->skip = inf->depth;
488: }
489: else
490: start(inf, el, attr); /* This does rest of start handling */
491: }
492:
493: inf->depth++;
494: } /* End of rawstart */
495:
496: void XMLCALL
497: rawend(void *data, const char *el) {
498: Parseinfo *inf = (Parseinfo *) data;
499:
500: inf->depth--;
501:
502: if (! inf->skip)
503: end(inf, el); /* This does rest of end handling */
504:
505: if (inf->skip == inf->depth)
506: inf->skip = 0;
507: } /* End rawend */
508: </pre>
509:
510: <p>Notice in the above example the difference in how depth is
511: manipulated in the start and end handlers. The end tag handler should
512: be the mirror image of the start tag handler. This is necessary to
513: properly model containment. Since, in the start tag handler, we
514: incremented depth <em>after</em> the main body of start tag code, then
515: in the end handler, we need to manipulate it <em>before</em> the main
516: body. If we'd decided to increment it first thing in the start
517: handler, then we'd have had to decrement it last thing in the end
518: handler.</p>
519:
520: <h3 id="userdata">Communicating between handlers</h3>
521:
522: <p>In order to be able to pass information between different handlers
523: without using globals, you'll need to define a data structure to hold
524: the shared variables. You can then tell Expat (with the <code><a href=
525: "#XML_SetUserData" >XML_SetUserData</a></code> function) to pass a
526: pointer to this structure to the handlers. This is the first
527: argument received by most handlers. In the <a href="#reference"
528: >reference section</a>, an argument to a callback function is named
529: <code>userData</code> and have type <code>void *</code> if the user
530: data is passed; it will have the type <code>XML_Parser</code> if the
531: parser itself is passed. When the parser is passed, the user data may
532: be retrieved using <code><a href="#XML_GetUserData"
533: >XML_GetUserData</a></code>.</p>
534:
535: <p>One common case where multiple calls to a single handler may need
536: to communicate using an application data structure is the case when
537: content passed to the character data handler (set by <code><a href=
538: "#XML_SetCharacterDataHandler"
539: >XML_SetCharacterDataHandler</a></code>) needs to be accumulated. A
540: common first-time mistake with any of the event-oriented interfaces to
541: an XML parser is to expect all the text contained in an element to be
542: reported by a single call to the character data handler. Expat, like
543: many other XML parsers, reports such data as a sequence of calls;
544: there's no way to know when the end of the sequence is reached until a
545: different callback is made. A buffer referenced by the user data
546: structure proves both an effective and convenient place to accumulate
547: character data.</p>
548:
549: <!-- XXX example needed here -->
550:
551:
552: <h3>XML Version</h3>
553:
554: <p>Expat is an XML 1.0 parser, and as such never complains based on
555: the value of the <code>version</code> pseudo-attribute in the XML
556: declaration, if present.</p>
557:
558: <p>If an application needs to check the version number (to support
559: alternate processing), it should use the <code><a href=
560: "#XML_SetXmlDeclHandler" >XML_SetXmlDeclHandler</a></code> function to
561: set a handler that uses the information in the XML declaration to
562: determine what to do. This example shows how to check that only a
563: version number of <code>"1.0"</code> is accepted:</p>
564:
565: <pre class="eg">
566: static int wrong_version;
567: static XML_Parser parser;
568:
569: static void XMLCALL
570: xmldecl_handler(void *userData,
571: const XML_Char *version,
572: const XML_Char *encoding,
573: int standalone)
574: {
575: static const XML_Char Version_1_0[] = {'1', '.', '0', 0};
576:
577: int i;
578:
579: for (i = 0; i < (sizeof(Version_1_0) / sizeof(Version_1_0[0])); ++i) {
580: if (version[i] != Version_1_0[i]) {
581: wrong_version = 1;
582: /* also clear all other handlers: */
583: XML_SetCharacterDataHandler(parser, NULL);
584: ...
585: return;
586: }
587: }
588: ...
589: }
590: </pre>
591:
592: <h3>Namespace Processing</h3>
593:
594: <p>When the parser is created using the <code><a href=
595: "#XML_ParserCreateNS" >XML_ParserCreateNS</a></code>, function, Expat
596: performs namespace processing. Under namespace processing, Expat
597: consumes <code>xmlns</code> and <code>xmlns:...</code> attributes,
598: which declare namespaces for the scope of the element in which they
599: occur. This means that your start handler will not see these
600: attributes. Your application can still be informed of these
601: declarations by setting namespace declaration handlers with <a href=
602: "#XML_SetNamespaceDeclHandler"
603: ><code>XML_SetNamespaceDeclHandler</code></a>.</p>
604:
605: <p>Element type and attribute names that belong to a given namespace
606: are passed to the appropriate handler in expanded form. By default
607: this expanded form is a concatenation of the namespace URI, the
608: separator character (which is the 2nd argument to <code><a href=
609: "#XML_ParserCreateNS" >XML_ParserCreateNS</a></code>), and the local
610: name (i.e. the part after the colon). Names with undeclared prefixes
611: are not well-formed when namespace processing is enabled, and will
612: trigger an error. Unprefixed attribute names are never expanded,
613: and unprefixed element names are only expanded when they are in the
614: scope of a default namespace.</p>
615:
616: <p>However if <code><a href= "#XML_SetReturnNSTriplet"
617: >XML_SetReturnNSTriplet</a></code> has been called with a non-zero
618: <code>do_nst</code> parameter, then the expanded form for names with
619: an explicit prefix is a concatenation of: URI, separator, local name,
620: separator, prefix.</p>
621:
622: <p>You can set handlers for the start of a namespace declaration and
623: for the end of a scope of a declaration with the <code><a href=
624: "#XML_SetNamespaceDeclHandler" >XML_SetNamespaceDeclHandler</a></code>
625: function. The StartNamespaceDeclHandler is called prior to the start
626: tag handler and the EndNamespaceDeclHandler is called after the
627: corresponding end tag that ends the namespace's scope. The namespace
628: start handler gets passed the prefix and URI for the namespace. For a
629: default namespace declaration (xmlns='...'), the prefix will be null.
630: The URI will be null for the case where the default namespace is being
631: unset. The namespace end handler just gets the prefix for the closing
632: scope.</p>
633:
634: <p>These handlers are called for each declaration. So if, for
635: instance, a start tag had three namespace declarations, then the
636: StartNamespaceDeclHandler would be called three times before the start
637: tag handler is called, once for each declaration.</p>
638:
639: <h3>Character Encodings</h3>
640:
641: <p>While XML is based on Unicode, and every XML processor is required
642: to recognized UTF-8 and UTF-16 (1 and 2 byte encodings of Unicode),
643: other encodings may be declared in XML documents or entities. For the
644: main document, an XML declaration may contain an encoding
645: declaration:</p>
646: <pre>
647: <?xml version="1.0" encoding="ISO-8859-2"?>
648: </pre>
649:
650: <p>External parsed entities may begin with a text declaration, which
651: looks like an XML declaration with just an encoding declaration:</p>
652: <pre>
653: <?xml encoding="Big5"?>
654: </pre>
655:
656: <p>With Expat, you may also specify an encoding at the time of
657: creating a parser. This is useful when the encoding information may
658: come from a source outside the document itself (like a higher level
659: protocol.)</p>
660:
661: <p><a name="builtin_encodings"></a>There are four built-in encodings
662: in Expat:</p>
663: <ul>
664: <li>UTF-8</li>
665: <li>UTF-16</li>
666: <li>ISO-8859-1</li>
667: <li>US-ASCII</li>
668: </ul>
669:
670: <p>Anything else discovered in an encoding declaration or in the
671: protocol encoding specified in the parser constructor, triggers a call
672: to the <code>UnknownEncodingHandler</code>. This handler gets passed
673: the encoding name and a pointer to an <code>XML_Encoding</code> data
674: structure. Your handler must fill in this structure and return
675: <code>XML_STATUS_OK</code> if it knows how to deal with the
676: encoding. Otherwise the handler should return
677: <code>XML_STATUS_ERROR</code>. The handler also gets passed a pointer
678: to an optional application data structure that you may indicate when
679: you set the handler.</p>
680:
681: <p>Expat places restrictions on character encodings that it can
682: support by filling in the <code>XML_Encoding</code> structure.
683: include file:</p>
684: <ol>
685: <li>Every ASCII character that can appear in a well-formed XML document
686: must be represented by a single byte, and that byte must correspond to
687: it's ASCII encoding (except for the characters $@\^'{}~)</li>
688: <li>Characters must be encoded in 4 bytes or less.</li>
689: <li>All characters encoded must have Unicode scalar values less than or
690: equal to 65535 (0xFFFF)<em>This does not apply to the built-in support
691: for UTF-16 and UTF-8</em></li>
692: <li>No character may be encoded by more that one distinct sequence of
693: bytes</li>
694: </ol>
695:
696: <p><code>XML_Encoding</code> contains an array of integers that
697: correspond to the 1st byte of an encoding sequence. If the value in
698: the array for a byte is zero or positive, then the byte is a single
699: byte encoding that encodes the Unicode scalar value contained in the
700: array. A -1 in this array indicates a malformed byte. If the value is
701: -2, -3, or -4, then the byte is the beginning of a 2, 3, or 4 byte
702: sequence respectively. Multi-byte sequences are sent to the convert
703: function pointed at in the <code>XML_Encoding</code> structure. This
704: function should return the Unicode scalar value for the sequence or -1
705: if the sequence is malformed.</p>
706:
707: <p>One pitfall that novice Expat users are likely to fall into is that
708: although Expat may accept input in various encodings, the strings that
709: it passes to the handlers are always encoded in UTF-8 or UTF-16
710: (depending on how Expat was compiled). Your application is responsible
711: for any translation of these strings into other encodings.</p>
712:
713: <h3>Handling External Entity References</h3>
714:
715: <p>Expat does not read or parse external entities directly. Note that
716: any external DTD is a special case of an external entity. If you've
717: set no <code>ExternalEntityRefHandler</code>, then external entity
718: references are silently ignored. Otherwise, it calls your handler with
719: the information needed to read and parse the external entity.</p>
720:
721: <p>Your handler isn't actually responsible for parsing the entity, but
722: it is responsible for creating a subsidiary parser with <code><a href=
723: "#XML_ExternalEntityParserCreate"
724: >XML_ExternalEntityParserCreate</a></code> that will do the job. This
725: returns an instance of <code>XML_Parser</code> that has handlers and
726: other data structures initialized from the parent parser. You may then
727: use <code><a href= "#XML_Parse" >XML_Parse</a></code> or <code><a
728: href= "#XML_ParseBuffer">XML_ParseBuffer</a></code> calls against this
729: parser. Since external entities my refer to other external entities,
730: your handler should be prepared to be called recursively.</p>
731:
732: <h3>Parsing DTDs</h3>
733:
734: <p>In order to parse parameter entities, before starting the parse,
735: you must call <code><a href= "#XML_SetParamEntityParsing"
736: >XML_SetParamEntityParsing</a></code> with one of the following
737: arguments:</p>
738: <dl>
739: <dt><code>XML_PARAM_ENTITY_PARSING_NEVER</code></dt>
740: <dd>Don't parse parameter entities or the external subset</dd>
741: <dt><code>XML_PARAM_ENTITY_PARSING_UNLESS_STANDALONE</code></dt>
742: <dd>Parse parameter entites and the external subset unless
743: <code>standalone</code> was set to "yes" in the XML declaration.</dd>
744: <dt><code>XML_PARAM_ENTITY_PARSING_ALWAYS</code></dt>
745: <dd>Always parse parameter entities and the external subset</dd>
746: </dl>
747:
748: <p>In order to read an external DTD, you also have to set an external
749: entity reference handler as described above.</p>
750:
751: <h3 id="stop-resume">Temporarily Stopping Parsing</h3>
752:
753: <p>Expat 1.95.8 introduces a new feature: its now possible to stop
754: parsing temporarily from within a handler function, even if more data
755: has already been passed into the parser. Applications for this
756: include</p>
757:
758: <ul>
759: <li>Supporting the <a href= "http://www.w3.org/TR/xinclude/"
760: >XInclude</a> specification.</li>
761:
762: <li>Delaying further processing until additional information is
763: available from some other source.</li>
764:
765: <li>Adjusting processor load as task priorities shift within an
766: application.</li>
767:
768: <li>Stopping parsing completely (simply free or reset the parser
769: instead of resuming in the outer parsing loop). This can be useful
770: if a application-domain error is found in the XML being parsed or if
771: the result of the parse is determined not to be useful after
772: all.</li>
773: </ul>
774:
775: <p>To take advantage of this feature, the main parsing loop of an
776: application needs to support this specifically. It cannot be
777: supported with a parsing loop compatible with Expat 1.95.7 or
778: earlier (though existing loops will continue to work without
779: supporting the stop/resume feature).</p>
780:
781: <p>An application that uses this feature for a single parser will have
782: the rough structure (in pseudo-code):</p>
783:
784: <pre class="pseudocode">
785: fd = open_input()
786: p = create_parser()
787:
788: if parse_xml(p, fd) {
789: /* suspended */
790:
791: int suspended = 1;
792:
793: while (suspended) {
794: do_something_else()
795: if ready_to_resume() {
796: suspended = continue_parsing(p, fd);
797: }
798: }
799: }
800: </pre>
801:
802: <p>An application that may resume any of several parsers based on
803: input (either from the XML being parsed or some other source) will
804: certainly have more interesting control structures.</p>
805:
806: <p>This C function could be used for the <code>parse_xml</code>
807: function mentioned in the pseudo-code above:</p>
808:
809: <pre class="eg">
810: #define BUFF_SIZE 10240
811:
812: /* Parse a document from the open file descriptor 'fd' until the parse
813: is complete (the document has been completely parsed, or there's
814: been an error), or the parse is stopped. Return non-zero when
815: the parse is merely suspended.
816: */
817: int
818: parse_xml(XML_Parser p, int fd)
819: {
820: for (;;) {
821: int last_chunk;
822: int bytes_read;
823: enum XML_Status status;
824:
825: void *buff = XML_GetBuffer(p, BUFF_SIZE);
826: if (buff == NULL) {
827: /* handle error... */
828: return 0;
829: }
830: bytes_read = read(fd, buff, BUFF_SIZE);
831: if (bytes_read < 0) {
832: /* handle error... */
833: return 0;
834: }
835: status = XML_ParseBuffer(p, bytes_read, bytes_read == 0);
836: switch (status) {
837: case XML_STATUS_ERROR:
838: /* handle error... */
839: return 0;
840: case XML_STATUS_SUSPENDED:
841: return 1;
842: }
843: if (bytes_read == 0)
844: return 0;
845: }
846: }
847: </pre>
848:
849: <p>The corresponding <code>continue_parsing</code> function is
850: somewhat simpler, since it only need deal with the return code from
851: <code><a href= "#XML_ResumeParser">XML_ResumeParser</a></code>; it can
852: delegate the input handling to the <code>parse_xml</code>
853: function:</p>
854:
855: <pre class="eg">
856: /* Continue parsing a document which had been suspended. The 'p' and
857: 'fd' arguments are the same as passed to parse_xml(). Return
858: non-zero when the parse is suspended.
859: */
860: int
861: continue_parsing(XML_Parser p, int fd)
862: {
863: enum XML_Status status = XML_ResumeParser(p);
864: switch (status) {
865: case XML_STATUS_ERROR:
866: /* handle error... */
867: return 0;
868: case XML_ERROR_NOT_SUSPENDED:
869: /* handle error... */
870: return 0;.
871: case XML_STATUS_SUSPENDED:
872: return 1;
873: }
874: return parse_xml(p, fd);
875: }
876: </pre>
877:
878: <p>Now that we've seen what a mess the top-level parsing loop can
879: become, what have we gained? Very simply, we can now use the <code><a
880: href= "#XML_StopParser" >XML_StopParser</a></code> function to stop
881: parsing, without having to go to great lengths to avoid additional
882: processing that we're expecting to ignore. As a bonus, we get to stop
883: parsing <em>temporarily</em>, and come back to it when we're
884: ready.</p>
885:
886: <p>To stop parsing from a handler function, use the <code><a href=
887: "#XML_StopParser" >XML_StopParser</a></code> function. This function
888: takes two arguments; the parser being stopped and a flag indicating
889: whether the parse can be resumed in the future.</p>
890:
891: <!-- XXX really need more here -->
892:
893:
894: <hr />
895: <!-- ================================================================ -->
896:
897: <h2><a name="reference">Expat Reference</a></h2>
898:
899: <h3><a name="creation">Parser Creation</a></h3>
900:
901: <pre class="fcndec" id="XML_ParserCreate">
902: XML_Parser XMLCALL
903: XML_ParserCreate(const XML_Char *encoding);
904: </pre>
905: <div class="fcndef">
906: Construct a new parser. If encoding is non-null, it specifies a
907: character encoding to use for the document. This overrides the document
908: encoding declaration. There are four built-in encodings:
909: <ul>
910: <li>US-ASCII</li>
911: <li>UTF-8</li>
912: <li>UTF-16</li>
913: <li>ISO-8859-1</li>
914: </ul>
915: Any other value will invoke a call to the UnknownEncodingHandler.
916: </div>
917:
918: <pre class="fcndec" id="XML_ParserCreateNS">
919: XML_Parser XMLCALL
920: XML_ParserCreateNS(const XML_Char *encoding,
921: XML_Char sep);
922: </pre>
923: <div class="fcndef">
924: Constructs a new parser that has namespace processing in effect. Namespace
925: expanded element names and attribute names are returned as a concatenation
926: of the namespace URI, <em>sep</em>, and the local part of the name. This
927: means that you should pick a character for <em>sep</em> that can't be part
928: of an URI. Since Expat does not check namespace URIs for conformance, the
929: only safe choice for a namespace separator is a character that is illegal
930: in XML. For instance, <code>'\xFF'</code> is not legal in UTF-8, and
931: <code>'\xFFFF'</code> is not legal in UTF-16. There is a special case when
932: <em>sep</em> is the null character <code>'\0'</code>: the namespace URI and
933: the local part will be concatenated without any separator - this is intended
934: to support RDF processors. It is a programming error to use the null separator
935: with <a href= "#XML_SetReturnNSTriplet">namespace triplets</a>.</div>
936:
937: <pre class="fcndec" id="XML_ParserCreate_MM">
938: XML_Parser XMLCALL
939: XML_ParserCreate_MM(const XML_Char *encoding,
940: const XML_Memory_Handling_Suite *ms,
941: const XML_Char *sep);
942: </pre>
943: <pre class="signature">
944: typedef struct {
945: void *(XMLCALL *malloc_fcn)(size_t size);
946: void *(XMLCALL *realloc_fcn)(void *ptr, size_t size);
947: void (XMLCALL *free_fcn)(void *ptr);
948: } XML_Memory_Handling_Suite;
949: </pre>
950: <div class="fcndef">
951: <p>Construct a new parser using the suite of memory handling functions
952: specified in <code>ms</code>. If <code>ms</code> is NULL, then use the
953: standard set of memory management functions. If <code>sep</code> is
954: non NULL, then namespace processing is enabled in the created parser
955: and the character pointed at by sep is used as the separator between
956: the namespace URI and the local part of the name.</p>
957: </div>
958:
959: <pre class="fcndec" id="XML_ExternalEntityParserCreate">
960: XML_Parser XMLCALL
961: XML_ExternalEntityParserCreate(XML_Parser p,
962: const XML_Char *context,
963: const XML_Char *encoding);
964: </pre>
965: <div class="fcndef">
966: Construct a new <code>XML_Parser</code> object for parsing an external
967: general entity. Context is the context argument passed in a call to a
968: ExternalEntityRefHandler. Other state information such as handlers,
969: user data, namespace processing is inherited from the parser passed as
970: the 1st argument. So you shouldn't need to call any of the behavior
971: changing functions on this parser (unless you want it to act
972: differently than the parent parser).
973: </div>
974:
975: <pre class="fcndec" id="XML_ParserFree">
976: void XMLCALL
977: XML_ParserFree(XML_Parser p);
978: </pre>
979: <div class="fcndef">
980: Free memory used by the parser. Your application is responsible for
981: freeing any memory associated with <a href="#userdata">user data</a>.
982: </div>
983:
984: <pre class="fcndec" id="XML_ParserReset">
985: XML_Bool XMLCALL
986: XML_ParserReset(XML_Parser p,
987: const XML_Char *encoding);
988: </pre>
989: <div class="fcndef">
990: Clean up the memory structures maintained by the parser so that it may
991: be used again. After this has been called, <code>parser</code> is
992: ready to start parsing a new document. All handlers are cleared from
993: the parser, except for the unknownEncodingHandler. The parser's external
994: state is re-initialized except for the values of ns and ns_triplets.
995: This function may not be used on a parser created using <code><a href=
996: "#XML_ExternalEntityParserCreate" >XML_ExternalEntityParserCreate</a
997: ></code>; it will return <code>XML_FALSE</code> in that case. Returns
998: <code>XML_TRUE</code> on success. Your application is responsible for
999: dealing with any memory associated with <a href="#userdata">user data</a>.
1000: </div>
1001:
1002: <h3><a name="parsing">Parsing</a></h3>
1003:
1004: <p>To state the obvious: the three parsing functions <code><a href=
1005: "#XML_Parse" >XML_Parse</a></code>, <code><a href= "#XML_ParseBuffer">
1006: XML_ParseBuffer</a></code> and <code><a href= "#XML_GetBuffer">
1007: XML_GetBuffer</a></code> must not be called from within a handler
1008: unless they operate on a separate parser instance, that is, one that
1009: did not call the handler. For example, it is OK to call the parsing
1010: functions from within an <code>XML_ExternalEntityRefHandler</code>,
1011: if they apply to the parser created by
1012: <code><a href= "#XML_ExternalEntityParserCreate"
1013: >XML_ExternalEntityParserCreate</a></code>.</p>
1014:
1015: <p>Note: the <code>len</code> argument passed to these functions
1016: should be considerably less than the maximum value for an integer,
1017: as it could create an integer overflow situation if the added
1018: lengths of a buffer and the unprocessed portion of the previous buffer
1019: exceed the maximum integer value. Input data at the end of a buffer
1020: will remain unprocessed if it is part of an XML token for which the
1021: end is not part of that buffer.</p>
1022:
1023: <pre class="fcndec" id="XML_Parse">
1024: enum XML_Status XMLCALL
1025: XML_Parse(XML_Parser p,
1026: const char *s,
1027: int len,
1028: int isFinal);
1029: </pre>
1030: <pre class="signature">
1031: enum XML_Status {
1032: XML_STATUS_ERROR = 0,
1033: XML_STATUS_OK = 1
1034: };
1035: </pre>
1036: <div class="fcndef">
1037: Parse some more of the document. The string <code>s</code> is a buffer
1038: containing part (or perhaps all) of the document. The number of bytes of s
1039: that are part of the document is indicated by <code>len</code>. This means
1040: that <code>s</code> doesn't have to be null terminated. It also means that
1041: if <code>len</code> is larger than the number of bytes in the block of
1042: memory that <code>s</code> points at, then a memory fault is likely. The
1043: <code>isFinal</code> parameter informs the parser that this is the last
1044: piece of the document. Frequently, the last piece is empty (i.e.
1045: <code>len</code> is zero.)
1046: If a parse error occurred, it returns <code>XML_STATUS_ERROR</code>.
1047: Otherwise it returns <code>XML_STATUS_OK</code> value.
1048: </div>
1049:
1050: <pre class="fcndec" id="XML_ParseBuffer">
1051: enum XML_Status XMLCALL
1052: XML_ParseBuffer(XML_Parser p,
1053: int len,
1054: int isFinal);
1055: </pre>
1056: <div class="fcndef">
1057: This is just like <code><a href= "#XML_Parse" >XML_Parse</a></code>,
1058: except in this case Expat provides the buffer. By obtaining the
1059: buffer from Expat with the <code><a href= "#XML_GetBuffer"
1060: >XML_GetBuffer</a></code> function, the application can avoid double
1061: copying of the input.
1062: </div>
1063:
1064: <pre class="fcndec" id="XML_GetBuffer">
1065: void * XMLCALL
1066: XML_GetBuffer(XML_Parser p,
1067: int len);
1068: </pre>
1069: <div class="fcndef">
1070: Obtain a buffer of size <code>len</code> to read a piece of the document
1071: into. A NULL value is returned if Expat can't allocate enough memory for
1072: this buffer. This has to be called prior to every call to
1073: <code><a href= "#XML_ParseBuffer" >XML_ParseBuffer</a></code>. A
1074: typical use would look like this:
1075:
1076: <pre class="eg">
1077: for (;;) {
1078: int bytes_read;
1079: void *buff = XML_GetBuffer(p, BUFF_SIZE);
1080: if (buff == NULL) {
1081: /* handle error */
1082: }
1083:
1084: bytes_read = read(docfd, buff, BUFF_SIZE);
1085: if (bytes_read < 0) {
1086: /* handle error */
1087: }
1088:
1089: if (! XML_ParseBuffer(p, bytes_read, bytes_read == 0)) {
1090: /* handle parse error */
1091: }
1092:
1093: if (bytes_read == 0)
1094: break;
1095: }
1096: </pre>
1097: </div>
1098:
1099: <pre class="fcndec" id="XML_StopParser">
1100: enum XML_Status XMLCALL
1101: XML_StopParser(XML_Parser p,
1102: XML_Bool resumable);
1103: </pre>
1104: <div class="fcndef">
1105:
1106: <p>Stops parsing, causing <code><a href= "#XML_Parse"
1107: >XML_Parse</a></code> or <code><a href= "#XML_ParseBuffer"
1108: >XML_ParseBuffer</a></code> to return. Must be called from within a
1109: call-back handler, except when aborting (when <code>resumable</code>
1110: is <code>XML_FALSE</code>) an already suspended parser. Some
1111: call-backs may still follow because they would otherwise get
1112: lost, including
1113: <ul>
1114: <li> the end element handler for empty elements when stopped in the
1115: start element handler,</li>
1116: <li> the end namespace declaration handler when stopped in the end
1117: element handler,</li>
1118: <li> the character data handler when stopped in the character data handler
1119: while making multiple call-backs on a contiguous chunk of characters,</li>
1120: </ul>
1121: and possibly others.</p>
1122:
1123: <p>This can be called from most handlers, including DTD related
1124: call-backs, except when parsing an external parameter entity and
1125: <code>resumable</code> is <code>XML_TRUE</code>. Returns
1126: <code>XML_STATUS_OK</code> when successful,
1127: <code>XML_STATUS_ERROR</code> otherwise. The possible error codes
1128: are:</p>
1129: <dl>
1130: <dt><code>XML_ERROR_SUSPENDED</code></dt>
1131: <dd>when suspending an already suspended parser.</dd>
1132: <dt><code>XML_ERROR_FINISHED</code></dt>
1133: <dd>when the parser has already finished.</dd>
1134: <dt><code>XML_ERROR_SUSPEND_PE</code></dt>
1135: <dd>when suspending while parsing an external PE.</dd>
1136: </dl>
1137:
1138: <p>Since the stop/resume feature requires application support in the
1139: outer parsing loop, it is an error to call this function for a parser
1140: not being handled appropriately; see <a href= "#stop-resume"
1141: >Temporarily Stopping Parsing</a> for more information.</p>
1142:
1143: <p>When <code>resumable</code> is <code>XML_TRUE</code> then parsing
1144: is <em>suspended</em>, that is, <code><a href= "#XML_Parse"
1145: >XML_Parse</a></code> and <code><a href= "#XML_ParseBuffer"
1146: >XML_ParseBuffer</a></code> return <code>XML_STATUS_SUSPENDED</code>.
1147: Otherwise, parsing is <em>aborted</em>, that is, <code><a href=
1148: "#XML_Parse" >XML_Parse</a></code> and <code><a href=
1149: "#XML_ParseBuffer" >XML_ParseBuffer</a></code> return
1150: <code>XML_STATUS_ERROR</code> with error code
1151: <code>XML_ERROR_ABORTED</code>.</p>
1152:
1153: <p><strong>Note:</strong>
1154: This will be applied to the current parser instance only, that is, if
1155: there is a parent parser then it will continue parsing when the
1156: external entity reference handler returns. It is up to the
1157: implementation of that handler to call <code><a href=
1158: "#XML_StopParser" >XML_StopParser</a></code> on the parent parser
1159: (recursively), if one wants to stop parsing altogether.</p>
1160:
1161: <p>When suspended, parsing can be resumed by calling <code><a href=
1162: "#XML_ResumeParser" >XML_ResumeParser</a></code>.</p>
1163:
1164: <p>New in Expat 1.95.8.</p>
1165: </div>
1166:
1167: <pre class="fcndec" id="XML_ResumeParser">
1168: enum XML_Status XMLCALL
1169: XML_ResumeParser(XML_Parser p);
1170: </pre>
1171: <div class="fcndef">
1172: <p>Resumes parsing after it has been suspended with <code><a href=
1173: "#XML_StopParser" >XML_StopParser</a></code>. Must not be called from
1174: within a handler call-back. Returns same status codes as <code><a
1175: href= "#XML_Parse">XML_Parse</a></code> or <code><a href=
1176: "#XML_ParseBuffer" >XML_ParseBuffer</a></code>. An additional error
1177: code, <code>XML_ERROR_NOT_SUSPENDED</code>, will be returned if the
1178: parser was not currently suspended.</p>
1179:
1180: <p><strong>Note:</strong>
1181: This must be called on the most deeply nested child parser instance
1182: first, and on its parent parser only after the child parser has
1183: finished, to be applied recursively until the document entity's parser
1184: is restarted. That is, the parent parser will not resume by itself
1185: and it is up to the application to call <code><a href=
1186: "#XML_ResumeParser" >XML_ResumeParser</a></code> on it at the
1187: appropriate moment.</p>
1188:
1189: <p>New in Expat 1.95.8.</p>
1190: </div>
1191:
1192: <pre class="fcndec" id="XML_GetParsingStatus">
1193: void XMLCALL
1194: XML_GetParsingStatus(XML_Parser p,
1195: XML_ParsingStatus *status);
1196: </pre>
1197: <pre class="signature">
1198: enum XML_Parsing {
1199: XML_INITIALIZED,
1200: XML_PARSING,
1201: XML_FINISHED,
1202: XML_SUSPENDED
1203: };
1204:
1205: typedef struct {
1206: enum XML_Parsing parsing;
1207: XML_Bool finalBuffer;
1208: } XML_ParsingStatus;
1209: </pre>
1210: <div class="fcndef">
1211: <p>Returns status of parser with respect to being initialized,
1212: parsing, finished, or suspended, and whether the final buffer is being
1213: processed. The <code>status</code> parameter <em>must not</em> be
1214: NULL.</p>
1215:
1216: <p>New in Expat 1.95.8.</p>
1217: </div>
1218:
1219:
1220: <h3><a name="setting">Handler Setting</a></h3>
1221:
1222: <p>Although handlers are typically set prior to parsing and left alone, an
1223: application may choose to set or change the handler for a parsing event
1224: while the parse is in progress. For instance, your application may choose
1225: to ignore all text not descended from a <code>para</code> element. One
1226: way it could do this is to set the character handler when a para start tag
1227: is seen, and unset it for the corresponding end tag.</p>
1228:
1229: <p>A handler may be <em>unset</em> by providing a NULL pointer to the
1230: appropriate handler setter. None of the handler setting functions have
1231: a return value.</p>
1232:
1233: <p>Your handlers will be receiving strings in arrays of type
1234: <code>XML_Char</code>. This type is conditionally defined in expat.h as
1235: either <code>char</code>, <code>wchar_t</code> or <code>unsigned short</code>.
1236: The former implies UTF-8 encoding, the latter two imply UTF-16 encoding.
1237: Note that you'll receive them in this form independent of the original
1238: encoding of the document.</p>
1239:
1240: <div class="handler">
1241: <pre class="setter" id="XML_SetStartElementHandler">
1242: void XMLCALL
1243: XML_SetStartElementHandler(XML_Parser p,
1244: XML_StartElementHandler start);
1245: </pre>
1246: <pre class="signature">
1247: typedef void
1248: (XMLCALL *XML_StartElementHandler)(void *userData,
1249: const XML_Char *name,
1250: const XML_Char **atts);
1251: </pre>
1252: <p>Set handler for start (and empty) tags. Attributes are passed to the start
1253: handler as a pointer to a vector of char pointers. Each attribute seen in
1254: a start (or empty) tag occupies 2 consecutive places in this vector: the
1255: attribute name followed by the attribute value. These pairs are terminated
1256: by a null pointer.</p>
1257: <p>Note that an empty tag generates a call to both start and end handlers
1258: (in that order).</p>
1259: </div>
1260:
1261: <div class="handler">
1262: <pre class="setter" id="XML_SetEndElementHandler">
1263: void XMLCALL
1264: XML_SetEndElementHandler(XML_Parser p,
1265: XML_EndElementHandler);
1266: </pre>
1267: <pre class="signature">
1268: typedef void
1269: (XMLCALL *XML_EndElementHandler)(void *userData,
1270: const XML_Char *name);
1271: </pre>
1272: <p>Set handler for end (and empty) tags. As noted above, an empty tag
1273: generates a call to both start and end handlers.</p>
1274: </div>
1275:
1276: <div class="handler">
1277: <pre class="setter" id="XML_SetElementHandler">
1278: void XMLCALL
1279: XML_SetElementHandler(XML_Parser p,
1280: XML_StartElementHandler start,
1281: XML_EndElementHandler end);
1282: </pre>
1283: <p>Set handlers for start and end tags with one call.</p>
1284: </div>
1285:
1286: <div class="handler">
1287: <pre class="setter" id="XML_SetCharacterDataHandler">
1288: void XMLCALL
1289: XML_SetCharacterDataHandler(XML_Parser p,
1290: XML_CharacterDataHandler charhndl)
1291: </pre>
1292: <pre class="signature">
1293: typedef void
1294: (XMLCALL *XML_CharacterDataHandler)(void *userData,
1295: const XML_Char *s,
1296: int len);
1297: </pre>
1298: <p>Set a text handler. The string your handler receives
1299: is <em>NOT nul-terminated</em>. You have to use the length argument
1300: to deal with the end of the string. A single block of contiguous text
1301: free of markup may still result in a sequence of calls to this handler.
1302: In other words, if you're searching for a pattern in the text, it may
1303: be split across calls to this handler. Note: Setting this handler to NULL
1304: may <em>NOT immediately</em> terminate call-backs if the parser is currently
1305: processing such a single block of contiguous markup-free text, as the parser
1306: will continue calling back until the end of the block is reached.</p>
1307: </div>
1308:
1309: <div class="handler">
1310: <pre class="setter" id="XML_SetProcessingInstructionHandler">
1311: void XMLCALL
1312: XML_SetProcessingInstructionHandler(XML_Parser p,
1313: XML_ProcessingInstructionHandler proc)
1314: </pre>
1315: <pre class="signature">
1316: typedef void
1317: (XMLCALL *XML_ProcessingInstructionHandler)(void *userData,
1318: const XML_Char *target,
1319: const XML_Char *data);
1320:
1321: </pre>
1322: <p>Set a handler for processing instructions. The target is the first word
1323: in the processing instruction. The data is the rest of the characters in
1324: it after skipping all whitespace after the initial word.</p>
1325: </div>
1326:
1327: <div class="handler">
1328: <pre class="setter" id="XML_SetCommentHandler">
1329: void XMLCALL
1330: XML_SetCommentHandler(XML_Parser p,
1331: XML_CommentHandler cmnt)
1332: </pre>
1333: <pre class="signature">
1334: typedef void
1335: (XMLCALL *XML_CommentHandler)(void *userData,
1336: const XML_Char *data);
1337: </pre>
1338: <p>Set a handler for comments. The data is all text inside the comment
1339: delimiters.</p>
1340: </div>
1341:
1342: <div class="handler">
1343: <pre class="setter" id="XML_SetStartCdataSectionHandler">
1344: void XMLCALL
1345: XML_SetStartCdataSectionHandler(XML_Parser p,
1346: XML_StartCdataSectionHandler start);
1347: </pre>
1348: <pre class="signature">
1349: typedef void
1350: (XMLCALL *XML_StartCdataSectionHandler)(void *userData);
1351: </pre>
1352: <p>Set a handler that gets called at the beginning of a CDATA section.</p>
1353: </div>
1354:
1355: <div class="handler">
1356: <pre class="setter" id="XML_SetEndCdataSectionHandler">
1357: void XMLCALL
1358: XML_SetEndCdataSectionHandler(XML_Parser p,
1359: XML_EndCdataSectionHandler end);
1360: </pre>
1361: <pre class="signature">
1362: typedef void
1363: (XMLCALL *XML_EndCdataSectionHandler)(void *userData);
1364: </pre>
1365: <p>Set a handler that gets called at the end of a CDATA section.</p>
1366: </div>
1367:
1368: <div class="handler">
1369: <pre class="setter" id="XML_SetCdataSectionHandler">
1370: void XMLCALL
1371: XML_SetCdataSectionHandler(XML_Parser p,
1372: XML_StartCdataSectionHandler start,
1373: XML_EndCdataSectionHandler end)
1374: </pre>
1375: <p>Sets both CDATA section handlers with one call.</p>
1376: </div>
1377:
1378: <div class="handler">
1379: <pre class="setter" id="XML_SetDefaultHandler">
1380: void XMLCALL
1381: XML_SetDefaultHandler(XML_Parser p,
1382: XML_DefaultHandler hndl)
1383: </pre>
1384: <pre class="signature">
1385: typedef void
1386: (XMLCALL *XML_DefaultHandler)(void *userData,
1387: const XML_Char *s,
1388: int len);
1389: </pre>
1390:
1391: <p>Sets a handler for any characters in the document which wouldn't
1392: otherwise be handled. This includes both data for which no handlers
1393: can be set (like some kinds of DTD declarations) and data which could
1394: be reported but which currently has no handler set. The characters
1395: are passed exactly as they were present in the XML document except
1396: that they will be encoded in UTF-8 or UTF-16. Line boundaries are not
1397: normalized. Note that a byte order mark character is not passed to the
1398: default handler. There are no guarantees about how characters are
1399: divided between calls to the default handler: for example, a comment
1400: might be split between multiple calls. Setting the handler with
1401: this call has the side effect of turning off expansion of references
1402: to internally defined general entities. Instead these references are
1403: passed to the default handler.</p>
1404:
1405: <p>See also <code><a
1406: href="#XML_DefaultCurrent">XML_DefaultCurrent</a></code>.</p>
1407: </div>
1408:
1409: <div class="handler">
1410: <pre class="setter" id="XML_SetDefaultHandlerExpand">
1411: void XMLCALL
1412: XML_SetDefaultHandlerExpand(XML_Parser p,
1413: XML_DefaultHandler hndl)
1414: </pre>
1415: <pre class="signature">
1416: typedef void
1417: (XMLCALL *XML_DefaultHandler)(void *userData,
1418: const XML_Char *s,
1419: int len);
1420: </pre>
1421: <p>This sets a default handler, but doesn't inhibit the expansion of
1422: internal entity references. The entity reference will not be passed
1423: to the default handler.</p>
1424:
1425: <p>See also <code><a
1426: href="#XML_DefaultCurrent">XML_DefaultCurrent</a></code>.</p>
1427: </div>
1428:
1429: <div class="handler">
1430: <pre class="setter" id="XML_SetExternalEntityRefHandler">
1431: void XMLCALL
1432: XML_SetExternalEntityRefHandler(XML_Parser p,
1433: XML_ExternalEntityRefHandler hndl)
1434: </pre>
1435: <pre class="signature">
1436: typedef int
1437: (XMLCALL *XML_ExternalEntityRefHandler)(XML_Parser p,
1438: const XML_Char *context,
1439: const XML_Char *base,
1440: const XML_Char *systemId,
1441: const XML_Char *publicId);
1442: </pre>
1443: <p>Set an external entity reference handler. This handler is also
1444: called for processing an external DTD subset if parameter entity parsing
1445: is in effect. (See <a href="#XML_SetParamEntityParsing">
1446: <code>XML_SetParamEntityParsing</code></a>.)</p>
1447:
1448: <p>The <code>context</code> parameter specifies the parsing context in
1449: the format expected by the <code>context</code> argument to <code><a
1450: href="#XML_ExternalEntityParserCreate"
1451: >XML_ExternalEntityParserCreate</a></code>. <code>code</code> is
1452: valid only until the handler returns, so if the referenced entity is
1453: to be parsed later, it must be copied. <code>context</code> is NULL
1454: only when the entity is a parameter entity, which is how one can
1455: differentiate between general and parameter entities.</p>
1456:
1457: <p>The <code>base</code> parameter is the base to use for relative
1458: system identifiers. It is set by <code><a
1459: href="#XML_SetBase">XML_SetBase</a></code> and may be NULL. The
1460: <code>publicId</code> parameter is the public id given in the entity
1461: declaration and may be NULL. <code>systemId</code> is the system
1462: identifier specified in the entity declaration and is never NULL.</p>
1463:
1464: <p>There are a couple of ways in which this handler differs from
1465: others. First, this handler returns a status indicator (an
1466: integer). <code>XML_STATUS_OK</code> should be returned for successful
1467: handling of the external entity reference. Returning
1468: <code>XML_STATUS_ERROR</code> indicates failure, and causes the
1469: calling parser to return an
1470: <code>XML_ERROR_EXTERNAL_ENTITY_HANDLING</code> error.</p>
1471:
1472: <p>Second, instead of having the user data as its first argument, it
1473: receives the parser that encountered the entity reference. This, along
1474: with the context parameter, may be used as arguments to a call to
1475: <code><a href= "#XML_ExternalEntityParserCreate"
1476: >XML_ExternalEntityParserCreate</a></code>. Using the returned
1477: parser, the body of the external entity can be recursively parsed.</p>
1478:
1479: <p>Since this handler may be called recursively, it should not be saving
1480: information into global or static variables.</p>
1481: </div>
1482:
1483: <pre class="fcndec" id="XML_SetExternalEntityRefHandlerArg">
1484: void XMLCALL
1485: XML_SetExternalEntityRefHandlerArg(XML_Parser p,
1486: void *arg)
1487: </pre>
1488: <div class="fcndef">
1489: <p>Set the argument passed to the ExternalEntityRefHandler. If
1490: <code>arg</code> is not NULL, it is the new value passed to the
1491: handler set using <code><a href="#XML_SetExternalEntityRefHandler"
1492: >XML_SetExternalEntityRefHandler</a></code>; if <code>arg</code> is
1493: NULL, the argument passed to the handler function will be the parser
1494: object itself.</p>
1495:
1496: <p><strong>Note:</strong>
1497: The type of <code>arg</code> and the type of the first argument to the
1498: ExternalEntityRefHandler do not match. This function takes a
1499: <code>void *</code> to be passed to the handler, while the handler
1500: accepts an <code>XML_Parser</code>. This is a historical accident,
1501: but will not be corrected before Expat 2.0 (at the earliest) to avoid
1502: causing compiler warnings for code that's known to work with this
1503: API. It is the responsibility of the application code to know the
1504: actual type of the argument passed to the handler and to manage it
1505: properly.</p>
1506: </div>
1507:
1508: <div class="handler">
1509: <pre class="setter" id="XML_SetSkippedEntityHandler">
1510: void XMLCALL
1511: XML_SetSkippedEntityHandler(XML_Parser p,
1512: XML_SkippedEntityHandler handler)
1513: </pre>
1514: <pre class="signature">
1515: typedef void
1516: (XMLCALL *XML_SkippedEntityHandler)(void *userData,
1517: const XML_Char *entityName,
1518: int is_parameter_entity);
1519: </pre>
1520: <p>Set a skipped entity handler. This is called in two situations:</p>
1521: <ol>
1522: <li>An entity reference is encountered for which no declaration
1523: has been read <em>and</em> this is not an error.</li>
1524: <li>An internal entity reference is read, but not expanded, because
1525: <a href="#XML_SetDefaultHandler"><code>XML_SetDefaultHandler</code></a>
1526: has been called.</li>
1527: </ol>
1528: <p>The <code>is_parameter_entity</code> argument will be non-zero for
1529: a parameter entity and zero for a general entity.</p> <p>Note: skipped
1530: parameter entities in declarations and skipped general entities in
1531: attribute values cannot be reported, because the event would be out of
1532: sync with the reporting of the declarations or attribute values</p>
1533: </div>
1534:
1535: <div class="handler">
1536: <pre class="setter" id="XML_SetUnknownEncodingHandler">
1537: void XMLCALL
1538: XML_SetUnknownEncodingHandler(XML_Parser p,
1539: XML_UnknownEncodingHandler enchandler,
1540: void *encodingHandlerData)
1541: </pre>
1542: <pre class="signature">
1543: typedef int
1544: (XMLCALL *XML_UnknownEncodingHandler)(void *encodingHandlerData,
1545: const XML_Char *name,
1546: XML_Encoding *info);
1547:
1548: typedef struct {
1549: int map[256];
1550: void *data;
1551: int (XMLCALL *convert)(void *data, const char *s);
1552: void (XMLCALL *release)(void *data);
1553: } XML_Encoding;
1554: </pre>
1555: <p>Set a handler to deal with encodings other than the <a
1556: href="#builtin_encodings">built in set</a>. This should be done before
1557: <code><a href= "#XML_Parse" >XML_Parse</a></code> or <code><a href=
1558: "#XML_ParseBuffer" >XML_ParseBuffer</a></code> have been called on the
1559: given parser.</p> <p>If the handler knows how to deal with an encoding
1560: with the given name, it should fill in the <code>info</code> data
1561: structure and return <code>XML_STATUS_OK</code>. Otherwise it
1562: should return <code>XML_STATUS_ERROR</code>. The handler will be called
1563: at most once per parsed (external) entity. The optional application
1564: data pointer <code>encodingHandlerData</code> will be passed back to
1565: the handler.</p>
1566:
1567: <p>The map array contains information for every possible possible leading
1568: byte in a byte sequence. If the corresponding value is >= 0, then it's
1569: a single byte sequence and the byte encodes that Unicode value. If the
1570: value is -1, then that byte is invalid as the initial byte in a sequence.
1571: If the value is -n, where n is an integer > 1, then n is the number of
1572: bytes in the sequence and the actual conversion is accomplished by a
1573: call to the function pointed at by convert. This function may return -1
1574: if the sequence itself is invalid. The convert pointer may be null if
1575: there are only single byte codes. The data parameter passed to the convert
1576: function is the data pointer from <code>XML_Encoding</code>. The
1577: string s is <em>NOT</em> nul-terminated and points at the sequence of
1578: bytes to be converted.</p>
1579:
1580: <p>The function pointed at by <code>release</code> is called by the
1581: parser when it is finished with the encoding. It may be NULL.</p>
1582: </div>
1583:
1584: <div class="handler">
1585: <pre class="setter" id="XML_SetStartNamespaceDeclHandler">
1586: void XMLCALL
1587: XML_SetStartNamespaceDeclHandler(XML_Parser p,
1588: XML_StartNamespaceDeclHandler start);
1589: </pre>
1590: <pre class="signature">
1591: typedef void
1592: (XMLCALL *XML_StartNamespaceDeclHandler)(void *userData,
1593: const XML_Char *prefix,
1594: const XML_Char *uri);
1595: </pre>
1596: <p>Set a handler to be called when a namespace is declared. Namespace
1597: declarations occur inside start tags. But the namespace declaration start
1598: handler is called before the start tag handler for each namespace declared
1599: in that start tag.</p>
1600: </div>
1601:
1602: <div class="handler">
1603: <pre class="setter" id="XML_SetEndNamespaceDeclHandler">
1604: void XMLCALL
1605: XML_SetEndNamespaceDeclHandler(XML_Parser p,
1606: XML_EndNamespaceDeclHandler end);
1607: </pre>
1608: <pre class="signature">
1609: typedef void
1610: (XMLCALL *XML_EndNamespaceDeclHandler)(void *userData,
1611: const XML_Char *prefix);
1612: </pre>
1613: <p>Set a handler to be called when leaving the scope of a namespace
1614: declaration. This will be called, for each namespace declaration,
1615: after the handler for the end tag of the element in which the
1616: namespace was declared.</p>
1617: </div>
1618:
1619: <div class="handler">
1620: <pre class="setter" id="XML_SetNamespaceDeclHandler">
1621: void XMLCALL
1622: XML_SetNamespaceDeclHandler(XML_Parser p,
1623: XML_StartNamespaceDeclHandler start,
1624: XML_EndNamespaceDeclHandler end)
1625: </pre>
1626: <p>Sets both namespace declaration handlers with a single call.</p>
1627: </div>
1628:
1629: <div class="handler">
1630: <pre class="setter" id="XML_SetXmlDeclHandler">
1631: void XMLCALL
1632: XML_SetXmlDeclHandler(XML_Parser p,
1633: XML_XmlDeclHandler xmldecl);
1634: </pre>
1635: <pre class="signature">
1636: typedef void
1637: (XMLCALL *XML_XmlDeclHandler)(void *userData,
1638: const XML_Char *version,
1639: const XML_Char *encoding,
1640: int standalone);
1641: </pre>
1642: <p>Sets a handler that is called for XML declarations and also for
1643: text declarations discovered in external entities. The way to
1644: distinguish is that the <code>version</code> parameter will be NULL
1645: for text declarations. The <code>encoding</code> parameter may be NULL
1646: for an XML declaration. The <code>standalone</code> argument will
1647: contain -1, 0, or 1 indicating respectively that there was no
1648: standalone parameter in the declaration, that it was given as no, or
1649: that it was given as yes.</p>
1650: </div>
1651:
1652: <div class="handler">
1653: <pre class="setter" id="XML_SetStartDoctypeDeclHandler">
1654: void XMLCALL
1655: XML_SetStartDoctypeDeclHandler(XML_Parser p,
1656: XML_StartDoctypeDeclHandler start);
1657: </pre>
1658: <pre class="signature">
1659: typedef void
1660: (XMLCALL *XML_StartDoctypeDeclHandler)(void *userData,
1661: const XML_Char *doctypeName,
1662: const XML_Char *sysid,
1663: const XML_Char *pubid,
1664: int has_internal_subset);
1665: </pre>
1666: <p>Set a handler that is called at the start of a DOCTYPE declaration,
1667: before any external or internal subset is parsed. Both <code>sysid</code>
1668: and <code>pubid</code> may be NULL. The <code>has_internal_subset</code>
1669: will be non-zero if the DOCTYPE declaration has an internal subset.</p>
1670: </div>
1671:
1672: <div class="handler">
1673: <pre class="setter" id="XML_SetEndDoctypeDeclHandler">
1674: void XMLCALL
1675: XML_SetEndDoctypeDeclHandler(XML_Parser p,
1676: XML_EndDoctypeDeclHandler end);
1677: </pre>
1678: <pre class="signature">
1679: typedef void
1680: (XMLCALL *XML_EndDoctypeDeclHandler)(void *userData);
1681: </pre>
1682: <p>Set a handler that is called at the end of a DOCTYPE declaration,
1683: after parsing any external subset.</p>
1684: </div>
1685:
1686: <div class="handler">
1687: <pre class="setter" id="XML_SetDoctypeDeclHandler">
1688: void XMLCALL
1689: XML_SetDoctypeDeclHandler(XML_Parser p,
1690: XML_StartDoctypeDeclHandler start,
1691: XML_EndDoctypeDeclHandler end);
1692: </pre>
1693: <p>Set both doctype handlers with one call.</p>
1694: </div>
1695:
1696: <div class="handler">
1697: <pre class="setter" id="XML_SetElementDeclHandler">
1698: void XMLCALL
1699: XML_SetElementDeclHandler(XML_Parser p,
1700: XML_ElementDeclHandler eldecl);
1701: </pre>
1702: <pre class="signature">
1703: typedef void
1704: (XMLCALL *XML_ElementDeclHandler)(void *userData,
1705: const XML_Char *name,
1706: XML_Content *model);
1707: </pre>
1708: <pre class="signature">
1709: enum XML_Content_Type {
1710: XML_CTYPE_EMPTY = 1,
1711: XML_CTYPE_ANY,
1712: XML_CTYPE_MIXED,
1713: XML_CTYPE_NAME,
1714: XML_CTYPE_CHOICE,
1715: XML_CTYPE_SEQ
1716: };
1717:
1718: enum XML_Content_Quant {
1719: XML_CQUANT_NONE,
1720: XML_CQUANT_OPT,
1721: XML_CQUANT_REP,
1722: XML_CQUANT_PLUS
1723: };
1724:
1725: typedef struct XML_cp XML_Content;
1726:
1727: struct XML_cp {
1728: enum XML_Content_Type type;
1729: enum XML_Content_Quant quant;
1730: const XML_Char * name;
1731: unsigned int numchildren;
1732: XML_Content * children;
1733: };
1734: </pre>
1735: <p>Sets a handler for element declarations in a DTD. The handler gets
1736: called with the name of the element in the declaration and a pointer
1737: to a structure that contains the element model. It is the
1738: application's responsibility to free this data structure using
1739: <code><a href="#XML_FreeContentModel"
1740: >XML_FreeContentModel</a></code>.</p>
1741:
1742: <p>The <code>model</code> argument is the root of a tree of
1743: <code>XML_Content</code> nodes. If <code>type</code> equals
1744: <code>XML_CTYPE_EMPTY</code> or <code>XML_CTYPE_ANY</code>, then
1745: <code>quant</code> will be <code>XML_CQUANT_NONE</code>, and the other
1746: fields will be zero or NULL. If <code>type</code> is
1747: <code>XML_CTYPE_MIXED</code>, then <code>quant</code> will be
1748: <code>XML_CQUANT_NONE</code> or <code>XML_CQUANT_REP</code> and
1749: <code>numchildren</code> will contain the number of elements that are
1750: allowed to be mixed in and <code>children</code> points to an array of
1751: <code>XML_Content</code> structures that will all have type
1752: XML_CTYPE_NAME with no quantification. Only the root node can be type
1753: <code>XML_CTYPE_EMPTY</code>, <code>XML_CTYPE_ANY</code>, or
1754: <code>XML_CTYPE_MIXED</code>.</p>
1755:
1756: <p>For type <code>XML_CTYPE_NAME</code>, the <code>name</code> field
1757: points to the name and the <code>numchildren</code> and
1758: <code>children</code> fields will be zero and NULL. The
1759: <code>quant</code> field will indicate any quantifiers placed on the
1760: name.</p>
1761:
1762: <p>Types <code>XML_CTYPE_CHOICE</code> and <code>XML_CTYPE_SEQ</code>
1763: indicate a choice or sequence respectively. The
1764: <code>numchildren</code> field indicates how many nodes in the choice
1765: or sequence and <code>children</code> points to the nodes.</p>
1766: </div>
1767:
1768: <div class="handler">
1769: <pre class="setter" id="XML_SetAttlistDeclHandler">
1770: void XMLCALL
1771: XML_SetAttlistDeclHandler(XML_Parser p,
1772: XML_AttlistDeclHandler attdecl);
1773: </pre>
1774: <pre class="signature">
1775: typedef void
1776: (XMLCALL *XML_AttlistDeclHandler)(void *userData,
1777: const XML_Char *elname,
1778: const XML_Char *attname,
1779: const XML_Char *att_type,
1780: const XML_Char *dflt,
1781: int isrequired);
1782: </pre>
1783: <p>Set a handler for attlist declarations in the DTD. This handler is
1784: called for <em>each</em> attribute. So a single attlist declaration
1785: with multiple attributes declared will generate multiple calls to this
1786: handler. The <code>elname</code> parameter returns the name of the
1787: element for which the attribute is being declared. The attribute name
1788: is in the <code>attname</code> parameter. The attribute type is in the
1789: <code>att_type</code> parameter. It is the string representing the
1790: type in the declaration with whitespace removed.</p>
1791:
1792: <p>The <code>dflt</code> parameter holds the default value. It will be
1793: NULL in the case of "#IMPLIED" or "#REQUIRED" attributes. You can
1794: distinguish these two cases by checking the <code>isrequired</code>
1795: parameter, which will be true in the case of "#REQUIRED" attributes.
1796: Attributes which are "#FIXED" will have also have a true
1797: <code>isrequired</code>, but they will have the non-NULL fixed value
1798: in the <code>dflt</code> parameter.</p>
1799: </div>
1800:
1801: <div class="handler">
1802: <pre class="setter" id="XML_SetEntityDeclHandler">
1803: void XMLCALL
1804: XML_SetEntityDeclHandler(XML_Parser p,
1805: XML_EntityDeclHandler handler);
1806: </pre>
1807: <pre class="signature">
1808: typedef void
1809: (XMLCALL *XML_EntityDeclHandler)(void *userData,
1810: const XML_Char *entityName,
1811: int is_parameter_entity,
1812: const XML_Char *value,
1813: int value_length,
1814: const XML_Char *base,
1815: const XML_Char *systemId,
1816: const XML_Char *publicId,
1817: const XML_Char *notationName);
1818: </pre>
1819: <p>Sets a handler that will be called for all entity declarations.
1820: The <code>is_parameter_entity</code> argument will be non-zero in the
1821: case of parameter entities and zero otherwise.</p>
1822:
1823: <p>For internal entities (<code><!ENTITY foo "bar"></code>),
1824: <code>value</code> will be non-NULL and <code>systemId</code>,
1825: <code>publicId</code>, and <code>notationName</code> will all be NULL.
1826: The value string is <em>not</em> NULL terminated; the length is
1827: provided in the <code>value_length</code> parameter. Do not use
1828: <code>value_length</code> to test for internal entities, since it is
1829: legal to have zero-length values. Instead check for whether or not
1830: <code>value</code> is NULL.</p> <p>The <code>notationName</code>
1831: argument will have a non-NULL value only for unparsed entity
1832: declarations.</p>
1833: </div>
1834:
1835: <div class="handler">
1836: <pre class="setter" id="XML_SetUnparsedEntityDeclHandler">
1837: void XMLCALL
1838: XML_SetUnparsedEntityDeclHandler(XML_Parser p,
1839: XML_UnparsedEntityDeclHandler h)
1840: </pre>
1841: <pre class="signature">
1842: typedef void
1843: (XMLCALL *XML_UnparsedEntityDeclHandler)(void *userData,
1844: const XML_Char *entityName,
1845: const XML_Char *base,
1846: const XML_Char *systemId,
1847: const XML_Char *publicId,
1848: const XML_Char *notationName);
1849: </pre>
1850: <p>Set a handler that receives declarations of unparsed entities. These
1851: are entity declarations that have a notation (NDATA) field:</p>
1852:
1853: <div id="eg"><pre>
1854: <!ENTITY logo SYSTEM "images/logo.gif" NDATA gif>
1855: </pre></div>
1856: <p>This handler is obsolete and is provided for backwards
1857: compatibility. Use instead <a href= "#XML_SetEntityDeclHandler"
1858: >XML_SetEntityDeclHandler</a>.</p>
1859: </div>
1860:
1861: <div class="handler">
1862: <pre class="setter" id="XML_SetNotationDeclHandler">
1863: void XMLCALL
1864: XML_SetNotationDeclHandler(XML_Parser p,
1865: XML_NotationDeclHandler h)
1866: </pre>
1867: <pre class="signature">
1868: typedef void
1869: (XMLCALL *XML_NotationDeclHandler)(void *userData,
1870: const XML_Char *notationName,
1871: const XML_Char *base,
1872: const XML_Char *systemId,
1873: const XML_Char *publicId);
1874: </pre>
1875: <p>Set a handler that receives notation declarations.</p>
1876: </div>
1877:
1878: <div class="handler">
1879: <pre class="setter" id="XML_SetNotStandaloneHandler">
1880: void XMLCALL
1881: XML_SetNotStandaloneHandler(XML_Parser p,
1882: XML_NotStandaloneHandler h)
1883: </pre>
1884: <pre class="signature">
1885: typedef int
1886: (XMLCALL *XML_NotStandaloneHandler)(void *userData);
1887: </pre>
1888: <p>Set a handler that is called if the document is not "standalone".
1889: This happens when there is an external subset or a reference to a
1890: parameter entity, but does not have standalone set to "yes" in an XML
1891: declaration. If this handler returns <code>XML_STATUS_ERROR</code>,
1892: then the parser will throw an <code>XML_ERROR_NOT_STANDALONE</code>
1893: error.</p>
1894: </div>
1895:
1896: <h3><a name="position">Parse position and error reporting functions</a></h3>
1897:
1898: <p>These are the functions you'll want to call when the parse
1899: functions return <code>XML_STATUS_ERROR</code> (a parse error has
1900: occurred), although the position reporting functions are useful outside
1901: of errors. The position reported is the byte position (in the original
1902: document or entity encoding) of the first of the sequence of
1903: characters that generated the current event (or the error that caused
1904: the parse functions to return <code>XML_STATUS_ERROR</code>.) The
1905: exceptions are callbacks trigged by declarations in the document
1906: prologue, in which case they exact position reported is somewhere in the
1907: relevant markup, but not necessarily as meaningful as for other
1908: events.</p>
1909:
1910: <p>The position reporting functions are accurate only outside of the
1911: DTD. In other words, they usually return bogus information when
1912: called from within a DTD declaration handler.</p>
1913:
1914: <pre class="fcndec" id="XML_GetErrorCode">
1915: enum XML_Error XMLCALL
1916: XML_GetErrorCode(XML_Parser p);
1917: </pre>
1918: <div class="fcndef">
1919: Return what type of error has occurred.
1920: </div>
1921:
1922: <pre class="fcndec" id="XML_ErrorString">
1923: const XML_LChar * XMLCALL
1924: XML_ErrorString(enum XML_Error code);
1925: </pre>
1926: <div class="fcndef">
1927: Return a string describing the error corresponding to code.
1928: The code should be one of the enums that can be returned from
1929: <code><a href= "#XML_GetErrorCode" >XML_GetErrorCode</a></code>.
1930: </div>
1931:
1932: <pre class="fcndec" id="XML_GetCurrentByteIndex">
1933: XML_Index XMLCALL
1934: XML_GetCurrentByteIndex(XML_Parser p);
1935: </pre>
1936: <div class="fcndef">
1937: Return the byte offset of the position. This always corresponds to
1938: the values returned by <code><a href= "#XML_GetCurrentLineNumber"
1939: >XML_GetCurrentLineNumber</a></code> and <code><a href=
1940: "#XML_GetCurrentColumnNumber" >XML_GetCurrentColumnNumber</a></code>.
1941: </div>
1942:
1943: <pre class="fcndec" id="XML_GetCurrentLineNumber">
1944: XML_Size XMLCALL
1945: XML_GetCurrentLineNumber(XML_Parser p);
1946: </pre>
1947: <div class="fcndef">
1948: Return the line number of the position. The first line is reported as
1949: <code>1</code>.
1950: </div>
1951:
1952: <pre class="fcndec" id="XML_GetCurrentColumnNumber">
1953: XML_Size XMLCALL
1954: XML_GetCurrentColumnNumber(XML_Parser p);
1955: </pre>
1956: <div class="fcndef">
1957: Return the offset, from the beginning of the current line, of
1958: the position.
1959: </div>
1960:
1961: <pre class="fcndec" id="XML_GetCurrentByteCount">
1962: int XMLCALL
1963: XML_GetCurrentByteCount(XML_Parser p);
1964: </pre>
1965: <div class="fcndef">
1966: Return the number of bytes in the current event. Returns
1967: <code>0</code> if the event is inside a reference to an internal
1968: entity and for the end-tag event for empty element tags (the later can
1969: be used to distinguish empty-element tags from empty elements using
1970: separate start and end tags).
1971: </div>
1972:
1973: <pre class="fcndec" id="XML_GetInputContext">
1974: const char * XMLCALL
1975: XML_GetInputContext(XML_Parser p,
1976: int *offset,
1977: int *size);
1978: </pre>
1979: <div class="fcndef">
1980:
1981: <p>Returns the parser's input buffer, sets the integer pointed at by
1982: <code>offset</code> to the offset within this buffer of the current
1983: parse position, and set the integer pointed at by <code>size</code> to
1984: the size of the returned buffer.</p>
1985:
1986: <p>This should only be called from within a handler during an active
1987: parse and the returned buffer should only be referred to from within
1988: the handler that made the call. This input buffer contains the
1989: untranslated bytes of the input.</p>
1990:
1991: <p>Only a limited amount of context is kept, so if the event
1992: triggering a call spans over a very large amount of input, the actual
1993: parse position may be before the beginning of the buffer.</p>
1994:
1995: <p>If <code>XML_CONTEXT_BYTES</code> is not defined, this will always
1996: return NULL.</p>
1997: </div>
1998:
1999: <h3><a name="miscellaneous">Miscellaneous functions</a></h3>
2000:
2001: <p>The functions in this section either obtain state information from
2002: the parser or can be used to dynamicly set parser options.</p>
2003:
2004: <pre class="fcndec" id="XML_SetUserData">
2005: void XMLCALL
2006: XML_SetUserData(XML_Parser p,
2007: void *userData);
2008: </pre>
2009: <div class="fcndef">
2010: This sets the user data pointer that gets passed to handlers. It
2011: overwrites any previous value for this pointer. Note that the
2012: application is responsible for freeing the memory associated with
2013: <code>userData</code> when it is finished with the parser. So if you
2014: call this when there's already a pointer there, and you haven't freed
2015: the memory associated with it, then you've probably just leaked
2016: memory.
2017: </div>
2018:
2019: <pre class="fcndec" id="XML_GetUserData">
2020: void * XMLCALL
2021: XML_GetUserData(XML_Parser p);
2022: </pre>
2023: <div class="fcndef">
2024: This returns the user data pointer that gets passed to handlers.
2025: It is actually implemented as a macro.
2026: </div>
2027:
2028: <pre class="fcndec" id="XML_UseParserAsHandlerArg">
2029: void XMLCALL
2030: XML_UseParserAsHandlerArg(XML_Parser p);
2031: </pre>
2032: <div class="fcndef">
2033: After this is called, handlers receive the parser in their
2034: <code>userData</code> arguments. The user data can still be obtained
2035: using the <code><a href= "#XML_GetUserData"
2036: >XML_GetUserData</a></code> function.
2037: </div>
2038:
2039: <pre class="fcndec" id="XML_SetBase">
2040: enum XML_Status XMLCALL
2041: XML_SetBase(XML_Parser p,
2042: const XML_Char *base);
2043: </pre>
2044: <div class="fcndef">
2045: Set the base to be used for resolving relative URIs in system
2046: identifiers. The return value is <code>XML_STATUS_ERROR</code> if
2047: there's no memory to store base, otherwise it's
2048: <code>XML_STATUS_OK</code>.
2049: </div>
2050:
2051: <pre class="fcndec" id="XML_GetBase">
2052: const XML_Char * XMLCALL
2053: XML_GetBase(XML_Parser p);
2054: </pre>
2055: <div class="fcndef">
2056: Return the base for resolving relative URIs.
2057: </div>
2058:
2059: <pre class="fcndec" id="XML_GetSpecifiedAttributeCount">
2060: int XMLCALL
2061: XML_GetSpecifiedAttributeCount(XML_Parser p);
2062: </pre>
2063: <div class="fcndef">
2064: When attributes are reported to the start handler in the atts vector,
2065: attributes that were explicitly set in the element occur before any
2066: attributes that receive their value from default information in an
2067: ATTLIST declaration. This function returns the number of attributes
2068: that were explicitly set times two, thus giving the offset in the
2069: <code>atts</code> array passed to the start tag handler of the first
2070: attribute set due to defaults. It supplies information for the last
2071: call to a start handler. If called inside a start handler, then that
2072: means the current call.
2073: </div>
2074:
2075: <pre class="fcndec" id="XML_GetIdAttributeIndex">
2076: int XMLCALL
2077: XML_GetIdAttributeIndex(XML_Parser p);
2078: </pre>
2079: <div class="fcndef">
2080: Returns the index of the ID attribute passed in the atts array in the
2081: last call to <code><a href= "#XML_StartElementHandler"
2082: >XML_StartElementHandler</a></code>, or -1 if there is no ID
2083: attribute. If called inside a start handler, then that means the
2084: current call.
2085: </div>
2086:
2087: <pre class="fcndec" id="XML_GetAttributeInfo">
2088: const XML_AttrInfo * XMLCALL
2089: XML_GetAttributeInfo(XML_Parser parser);
2090: </pre>
2091: <pre class="signature">
2092: typedef struct {
2093: XML_Index nameStart; /* Offset to beginning of the attribute name. */
2094: XML_Index nameEnd; /* Offset after the attribute name's last byte. */
2095: XML_Index valueStart; /* Offset to beginning of the attribute value. */
2096: XML_Index valueEnd; /* Offset after the attribute value's last byte. */
2097: } XML_AttrInfo;
2098: </pre>
2099: <div class="fcndef">
2100: Returns an array of <code>XML_AttrInfo</code> structures for the
2101: attribute/value pairs passed in the last call to the
2102: <code>XML_StartElementHandler</code> that were specified
2103: in the start-tag rather than defaulted. Each attribute/value pair counts
2104: as 1; thus the number of entries in the array is
2105: <code>XML_GetSpecifiedAttributeCount(parser) / 2</code>.
2106: </div>
2107:
2108: <pre class="fcndec" id="XML_SetEncoding">
2109: enum XML_Status XMLCALL
2110: XML_SetEncoding(XML_Parser p,
2111: const XML_Char *encoding);
2112: </pre>
2113: <div class="fcndef">
2114: Set the encoding to be used by the parser. It is equivalent to
2115: passing a non-null encoding argument to the parser creation functions.
2116: It must not be called after <code><a href= "#XML_Parse"
2117: >XML_Parse</a></code> or <code><a href= "#XML_ParseBuffer"
2118: >XML_ParseBuffer</a></code> have been called on the given parser.
2119: Returns <code>XML_STATUS_OK</code> on success or
2120: <code>XML_STATUS_ERROR</code> on error.
2121: </div>
2122:
2123: <pre class="fcndec" id="XML_SetParamEntityParsing">
2124: int XMLCALL
2125: XML_SetParamEntityParsing(XML_Parser p,
2126: enum XML_ParamEntityParsing code);
2127: </pre>
2128: <div class="fcndef">
2129: This enables parsing of parameter entities, including the external
2130: parameter entity that is the external DTD subset, according to
2131: <code>code</code>.
2132: The choices for <code>code</code> are:
2133: <ul>
2134: <li><code>XML_PARAM_ENTITY_PARSING_NEVER</code></li>
2135: <li><code>XML_PARAM_ENTITY_PARSING_UNLESS_STANDALONE</code></li>
2136: <li><code>XML_PARAM_ENTITY_PARSING_ALWAYS</code></li>
2137: </ul>
2138: <b>Note:</b> If <code>XML_SetParamEntityParsing</code> is called after
2139: <code>XML_Parse</code> or <code>XML_ParseBuffer</code>, then it has
2140: no effect and will always return 0.
2141: </div>
2142:
2143: <pre class="fcndec" id="XML_SetHashSalt">
2144: int XMLCALL
2145: XML_SetHashSalt(XML_Parser p,
2146: unsigned long hash_salt);
2147: </pre>
2148: <div class="fcndef">
2149: Sets the hash salt to use for internal hash calculations.
2150: Helps in preventing DoS attacks based on predicting hash
2151: function behavior. In order to have an effect this must be called
2152: before parsing has started. Returns 1 if successful, 0 when called
2153: after <code>XML_Parse</code> or <code>XML_ParseBuffer</code>.
2154: <p><b>Note:</b> This call is optional, as the parser will auto-generate a new
2155: random salt value if no value has been set at the start of parsing.</p>
2156: </div>
2157:
2158: <pre class="fcndec" id="XML_UseForeignDTD">
2159: enum XML_Error XMLCALL
2160: XML_UseForeignDTD(XML_Parser parser, XML_Bool useDTD);
2161: </pre>
2162: <div class="fcndef">
2163: <p>This function allows an application to provide an external subset
2164: for the document type declaration for documents which do not specify
2165: an external subset of their own. For documents which specify an
2166: external subset in their DOCTYPE declaration, the application-provided
2167: subset will be ignored. If the document does not contain a DOCTYPE
2168: declaration at all and <code>useDTD</code> is true, the
2169: application-provided subset will be parsed, but the
2170: <code>startDoctypeDeclHandler</code> and
2171: <code>endDoctypeDeclHandler</code> functions, if set, will not be
2172: called. The setting of parameter entity parsing, controlled using
2173: <code><a href= "#XML_SetParamEntityParsing"
2174: >XML_SetParamEntityParsing</a></code>, will be honored.</p>
2175:
2176: <p>The application-provided external subset is read by calling the
2177: external entity reference handler set via <code><a href=
2178: "#XML_SetExternalEntityRefHandler"
2179: >XML_SetExternalEntityRefHandler</a></code> with both
2180: <code>publicId</code> and <code>systemId</code> set to NULL.</p>
2181:
2182: <p>If this function is called after parsing has begun, it returns
2183: <code>XML_ERROR_CANT_CHANGE_FEATURE_ONCE_PARSING</code> and ignores
2184: <code>useDTD</code>. If called when Expat has been compiled without
2185: DTD support, it returns
2186: <code>XML_ERROR_FEATURE_REQUIRES_XML_DTD</code>. Otherwise, it
2187: returns <code>XML_ERROR_NONE</code>.</p>
2188:
2189: <p><b>Note:</b> For the purpose of checking WFC: Entity Declared, passing
2190: <code>useDTD == XML_TRUE</code> will make the parser behave as if
2191: the document had a DTD with an external subset. This holds true even if
2192: the external entity reference handler returns without action.</p>
2193: </div>
2194:
2195: <pre class="fcndec" id="XML_SetReturnNSTriplet">
2196: void XMLCALL
2197: XML_SetReturnNSTriplet(XML_Parser parser,
2198: int do_nst);
2199: </pre>
2200: <div class="fcndef">
2201: <p>
2202: This function only has an effect when using a parser created with
2203: <code><a href= "#XML_ParserCreateNS" >XML_ParserCreateNS</a></code>,
2204: i.e. when namespace processing is in effect. The <code>do_nst</code>
2205: sets whether or not prefixes are returned with names qualified with a
2206: namespace prefix. If this function is called with <code>do_nst</code>
2207: non-zero, then afterwards namespace qualified names (that is qualified
2208: with a prefix as opposed to belonging to a default namespace) are
2209: returned as a triplet with the three parts separated by the namespace
2210: separator specified when the parser was created. The order of
2211: returned parts is URI, local name, and prefix.</p> <p>If
2212: <code>do_nst</code> is zero, then namespaces are reported in the
2213: default manner, URI then local_name separated by the namespace
2214: separator.</p>
2215: </div>
2216:
2217: <pre class="fcndec" id="XML_DefaultCurrent">
2218: void XMLCALL
2219: XML_DefaultCurrent(XML_Parser parser);
2220: </pre>
2221: <div class="fcndef">
2222: This can be called within a handler for a start element, end element,
2223: processing instruction or character data. It causes the corresponding
2224: markup to be passed to the default handler set by <code><a
2225: href="#XML_SetDefaultHandler" >XML_SetDefaultHandler</a></code> or
2226: <code><a href="#XML_SetDefaultHandlerExpand"
2227: >XML_SetDefaultHandlerExpand</a></code>. It does nothing if there is
2228: not a default handler.
2229: </div>
2230:
2231: <pre class="fcndec" id="XML_ExpatVersion">
2232: XML_LChar * XMLCALL
2233: XML_ExpatVersion();
2234: </pre>
2235: <div class="fcndef">
2236: Return the library version as a string (e.g. <code>"expat_1.95.1"</code>).
2237: </div>
2238:
2239: <pre class="fcndec" id="XML_ExpatVersionInfo">
2240: struct XML_Expat_Version XMLCALL
2241: XML_ExpatVersionInfo();
2242: </pre>
2243: <pre class="signature">
2244: typedef struct {
2245: int major;
2246: int minor;
2247: int micro;
2248: } XML_Expat_Version;
2249: </pre>
2250: <div class="fcndef">
2251: Return the library version information as a structure.
2252: Some macros are also defined that support compile-time tests of the
2253: library version:
2254: <ul>
2255: <li><code>XML_MAJOR_VERSION</code></li>
2256: <li><code>XML_MINOR_VERSION</code></li>
2257: <li><code>XML_MICRO_VERSION</code></li>
2258: </ul>
2259: Testing these constants is currently the best way to determine if
2260: particular parts of the Expat API are available.
2261: </div>
2262:
2263: <pre class="fcndec" id="XML_GetFeatureList">
2264: const XML_Feature * XMLCALL
2265: XML_GetFeatureList();
2266: </pre>
2267: <pre class="signature">
2268: enum XML_FeatureEnum {
2269: XML_FEATURE_END = 0,
2270: XML_FEATURE_UNICODE,
2271: XML_FEATURE_UNICODE_WCHAR_T,
2272: XML_FEATURE_DTD,
2273: XML_FEATURE_CONTEXT_BYTES,
2274: XML_FEATURE_MIN_SIZE,
2275: XML_FEATURE_SIZEOF_XML_CHAR,
2276: XML_FEATURE_SIZEOF_XML_LCHAR,
2277: XML_FEATURE_NS,
2278: XML_FEATURE_LARGE_SIZE
2279: };
2280:
2281: typedef struct {
2282: enum XML_FeatureEnum feature;
2283: XML_LChar *name;
2284: long int value;
2285: } XML_Feature;
2286: </pre>
2287: <div class="fcndef">
2288: <p>Returns a list of "feature" records, providing details on how
2289: Expat was configured at compile time. Most applications should not
2290: need to worry about this, but this information is otherwise not
2291: available from Expat. This function allows code that does need to
2292: check these features to do so at runtime.</p>
2293:
2294: <p>The return value is an array of <code>XML_Feature</code>,
2295: terminated by a record with a <code>feature</code> of
2296: <code>XML_FEATURE_END</code> and <code>name</code> of NULL,
2297: identifying the feature-test macros Expat was compiled with. Since an
2298: application that requires this kind of information needs to determine
2299: the type of character the <code>name</code> points to, records for the
2300: <code>XML_FEATURE_SIZEOF_XML_CHAR</code> and
2301: <code>XML_FEATURE_SIZEOF_XML_LCHAR</code> will be located at the
2302: beginning of the list, followed by <code>XML_FEATURE_UNICODE</code>
2303: and <code>XML_FEATURE_UNICODE_WCHAR_T</code>, if they are present at
2304: all.</p>
2305:
2306: <p>Some features have an associated value. If there isn't an
2307: associated value, the <code>value</code> field is set to 0. At this
2308: time, the following features have been defined to have values:</p>
2309:
2310: <dl>
2311: <dt><code>XML_FEATURE_SIZEOF_XML_CHAR</code></dt>
2312: <dd>The number of bytes occupied by one <code>XML_Char</code>
2313: character.</dd>
2314: <dt><code>XML_FEATURE_SIZEOF_XML_LCHAR</code></dt>
2315: <dd>The number of bytes occupied by one <code>XML_LChar</code>
2316: character.</dd>
2317: <dt><code>XML_FEATURE_CONTEXT_BYTES</code></dt>
2318: <dd>The maximum number of characters of context which can be
2319: reported by <code><a href= "#XML_GetInputContext"
2320: >XML_GetInputContext</a></code>.</dd>
2321: </dl>
2322: </div>
2323:
2324: <pre class="fcndec" id="XML_FreeContentModel">
2325: void XMLCALL
2326: XML_FreeContentModel(XML_Parser parser, XML_Content *model);
2327: </pre>
2328: <div class="fcndef">
2329: Function to deallocate the <code>model</code> argument passed to the
2330: <code>XML_ElementDeclHandler</code> callback set using <code><a
2331: href="#XML_SetElementDeclHandler" >XML_ElementDeclHandler</a></code>.
2332: This function should not be used for any other purpose.
2333: </div>
2334:
2335: <p>The following functions allow external code to share the memory
2336: allocator an <code>XML_Parser</code> has been configured to use. This
2337: is especially useful for third-party libraries that interact with a
2338: parser object created by application code, or heavily layered
2339: applications. This can be essential when using dynamically loaded
2340: libraries which use different C standard libraries (this can happen on
2341: Windows, at least).</p>
2342:
2343: <pre class="fcndec" id="XML_MemMalloc">
2344: void * XMLCALL
2345: XML_MemMalloc(XML_Parser parser, size_t size);
2346: </pre>
2347: <div class="fcndef">
2348: Allocate <code>size</code> bytes of memory using the allocator the
2349: <code>parser</code> object has been configured to use. Returns a
2350: pointer to the memory or NULL on failure. Memory allocated in this
2351: way must be freed using <code><a href="#XML_MemFree"
2352: >XML_MemFree</a></code>.
2353: </div>
2354:
2355: <pre class="fcndec" id="XML_MemRealloc">
2356: void * XMLCALL
2357: XML_MemRealloc(XML_Parser parser, void *ptr, size_t size);
2358: </pre>
2359: <div class="fcndef">
2360: Allocate <code>size</code> bytes of memory using the allocator the
2361: <code>parser</code> object has been configured to use.
2362: <code>ptr</code> must point to a block of memory allocated by <code><a
2363: href="#XML_MemMalloc" >XML_MemMalloc</a></code> or
2364: <code>XML_MemRealloc</code>, or be NULL. This function tries to
2365: expand the block pointed to by <code>ptr</code> if possible. Returns
2366: a pointer to the memory or NULL on failure. On success, the original
2367: block has either been expanded or freed. On failure, the original
2368: block has not been freed; the caller is responsible for freeing the
2369: original block. Memory allocated in this way must be freed using
2370: <code><a href="#XML_MemFree"
2371: >XML_MemFree</a></code>.
2372: </div>
2373:
2374: <pre class="fcndec" id="XML_MemFree">
2375: void XMLCALL
2376: XML_MemFree(XML_Parser parser, void *ptr);
2377: </pre>
2378: <div class="fcndef">
2379: Free a block of memory pointed to by <code>ptr</code>. The block must
2380: have been allocated by <code><a href="#XML_MemMalloc"
2381: >XML_MemMalloc</a></code> or <code>XML_MemRealloc</code>, or be NULL.
2382: </div>
2383:
2384: <hr />
2385: <p><a href="http://validator.w3.org/check/referer"><img
2386: src="valid-xhtml10.png" alt="Valid XHTML 1.0!"
2387: height="31" width="88" class="noborder" /></a></p>
2388: </div>
2389: </body>
2390: </html>
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