Expat is a library, written in C, for parsing XML documents. It's
-the underlying XML parser for the open source Mozilla project, Perl's
-XML::Parser, Python's xml.parsers.expat, and
-other open-source XML parsers.
This library is the creation of James Clark, who's also given us -groff (an nroff look-alike), Jade (an implemention of ISO's DSSSL -stylesheet language for SGML), XP (a Java XML parser package), XT (a -Java XSL engine). James was also the technical lead on the XML -Working Group at W3C that produced the XML specification.
- -This is free software, licensed under the MIT/X Consortium license. You may download it -from the Expat home page. -
- -The bulk of this document was originally commissioned as an article -by XML.com. They graciously allowed -Clark Cooper to retain copyright and to distribute it with Expat. -This version has been substantially extended to include documentation -on features which have been added since the original article was -published, and additional information on using the original -interface.
- --
Table of Contents
--
-
- Overview -
- Building and Installing -
- Using Expat -
- Reference
-
-
-
- Parser Creation Functions - - -
- Parsing Functions - - -
- Handler Setting Functions
-
-
-
- XML_SetStartElementHandler -
- XML_SetEndElementHandler -
- XML_SetElementHandler -
- XML_SetCharacterDataHandler -
- XML_SetProcessingInstructionHandler -
- XML_SetCommentHandler -
- XML_SetStartCdataSectionHandler -
- XML_SetEndCdataSectionHandler -
- XML_SetCdataSectionHandler -
- XML_SetDefaultHandler -
- XML_SetDefaultHandlerExpand -
- XML_SetExternalEntityRefHandler -
- XML_SetExternalEntityRefHandlerArg -
- XML_SetSkippedEntityHandler -
- XML_SetUnknownEncodingHandler -
- XML_SetStartNamespaceDeclHandler -
- XML_SetEndNamespaceDeclHandler -
- XML_SetNamespaceDeclHandler -
- XML_SetXmlDeclHandler -
- XML_SetStartDoctypeDeclHandler -
- XML_SetEndDoctypeDeclHandler -
- XML_SetDoctypeDeclHandler -
- XML_SetElementDeclHandler -
- XML_SetAttlistDeclHandler -
- XML_SetEntityDeclHandler -
- XML_SetUnparsedEntityDeclHandler -
- XML_SetNotationDeclHandler -
- XML_SetNotStandaloneHandler -
- - Parse Position and Error Reporting Functions - - -
- Miscellaneous Functions
-
-
-
- XML_SetUserData -
- XML_GetUserData -
- XML_UseParserAsHandlerArg -
- XML_SetBase -
- XML_GetBase -
- XML_GetSpecifiedAttributeCount -
- XML_GetIdAttributeIndex -
- XML_GetAttributeInfo -
- XML_SetEncoding -
- XML_SetParamEntityParsing -
- XML_SetHashSalt -
- XML_UseForeignDTD -
- XML_SetReturnNSTriplet -
- XML_DefaultCurrent -
- XML_ExpatVersion -
- XML_ExpatVersionInfo -
- XML_GetFeatureList -
- XML_FreeContentModel -
- XML_MemMalloc -
- XML_MemRealloc -
- XML_MemFree -
-
-
-
Overview
- -Expat is a stream-oriented parser. You register callback (or -handler) functions with the parser and then start feeding it the -document. As the parser recognizes parts of the document, it will -call the appropriate handler for that part (if you've registered one.) -The document is fed to the parser in pieces, so you can start parsing -before you have all the document. This also allows you to parse really -huge documents that won't fit into memory.
- -Expat can be intimidating due to the many kinds of handlers and -options you can set. But you only need to learn four functions in -order to do 90% of what you'll want to do with it:
- --
-
-
XML_ParserCreate
- - Create a new parser object. - -
XML_SetElementHandler
- - Set handlers for start and end tags. - -
XML_SetCharacterDataHandler
- - Set handler for text. - -
XML_Parse
- - Pass a buffer full of document to the parser -
These functions and others are described in the reference part of this document. The reference -section also describes in detail the parameters passed to the -different types of handlers.
- -Let's look at a very simple example program that only uses 3 of the
-above functions (it doesn't need to set a character handler.) The
-program outline.c prints an
-element outline, indenting child elements to distinguish them from the
-parent element that contains them. The start handler does all the
-work. It prints two indenting spaces for every level of ancestor
-elements, then it prints the element and attribute
-information. Finally it increments the global Depth
-variable.
-int Depth;
-
-void XMLCALL
-start(void *data, const char *el, const char **attr) {
- int i;
-
- for (i = 0; i < Depth; i++)
- printf(" ");
-
- printf("%s", el);
-
- for (i = 0; attr[i]; i += 2) {
- printf(" %s='%s'", attr[i], attr[i + 1]);
- }
-
- printf("\n");
- Depth++;
-} /* End of start handler */
-
-
-The end tag simply does the bookkeeping work of decrementing
-Depth.
-void XMLCALL
-end(void *data, const char *el) {
- Depth--;
-} /* End of end handler */
-
-
-Note the XMLCALL annotation used for the callbacks.
-This is used to ensure that the Expat and the callbacks are using the
-same calling convention in case the compiler options used for Expat
-itself and the client code are different. Expat tries not to care
-what the default calling convention is, though it may require that it
-be compiled with a default convention of "cdecl" on some platforms.
-For code which uses Expat, however, the calling convention is
-specified by the XMLCALL annotation on most platforms;
-callbacks should be defined using this annotation.
The XMLCALL annotation was added in Expat 1.95.7, but
-existing working Expat applications don't need to add it (since they
-are already using the "cdecl" calling convention, or they wouldn't be
-working). The annotation is only needed if the default calling
-convention may be something other than "cdecl". To use the annotation
-safely with older versions of Expat, you can conditionally define it
-after including Expat's header file:
-#include <expat.h> - -#ifndef XMLCALL -#if defined(_MSC_EXTENSIONS) && !defined(__BEOS__) && !defined(__CYGWIN__) -#define XMLCALL __cdecl -#elif defined(__GNUC__) -#define XMLCALL __attribute__((cdecl)) -#else -#define XMLCALL -#endif -#endif -- -
After creating the parser, the main program just has the job of -shoveling the document to the parser so that it can do its work.
- --
Building and Installing Expat
- -The Expat distribution comes as a compressed (with GNU gzip) tar -file. You may download the latest version from Source Forge. After -unpacking this, cd into the directory. Then follow either the Win32 -directions or Unix directions below.
- -Building under Win32
- -If you're using the GNU compiler under cygwin, follow the Unix -directions in the next section. Otherwise if you have Microsoft's -Developer Studio installed, then from Windows Explorer double-click on -"expat.vcxproj" in the lib directory and build and install in the usual -manner.
- -Alternatively, you may download the Win32 binary package that -contains the "expat.h" include file and a pre-built DLL.
- -Building under Unix (or GNU)
- -First you'll need to run the configure shell script in order to -configure the Makefiles and headers for your system.
- -If you're happy with all the defaults that configure picks for you, -and you have permission on your system to install into /usr/local, you -can install Expat with this sequence of commands:
- --./configure -make -make install -- -
There are some options that you can provide to this script, but the
-only one we'll mention here is the --prefix option. You
-can find out all the options available by running configure with just
-the --help option.
By default, the configure script sets things up so that the library
-gets installed in /usr/local/lib and the associated
-header file in /usr/local/include. But if you were to
-give the option, --prefix=/home/me/mystuff, then the
-library and header would get installed in
-/home/me/mystuff/lib and
-/home/me/mystuff/include respectively.
Configuring Expat Using the Pre-Processor
- -Expat's feature set can be configured using a small number of
-pre-processor definitions. The definition of this symbols does not
-affect the set of entry points for Expat, only the behavior of the API
-and the definition of character types in the case of
-XML_UNICODE_WCHAR_T. The symbols are:
-
-
- XML_DTD -
- Include support for using and reporting DTD-based content. If -this is defined, default attribute values from an external DTD subset -are reported and attribute value normalization occurs based on the -type of attributes defined in the external subset. Without -this, Expat has a smaller memory footprint and can be faster, but will -not load external entities or process conditional sections. This does -not affect the set of functions available in the API. - -
- XML_NS -
- When defined, support for the Namespaces in XML -specification is included. - -
- XML_UNICODE -
- When defined, character data reported to the application is
-encoded in UTF-16 using wide characters of the type
-
XML_Char. This is implied if -XML_UNICODE_WCHAR_Tis defined.
-
- - XML_UNICODE_WCHAR_T -
- If defined, causes the
XML_Charcharacter type to be -defined using thewchar_ttype; otherwise,unsigned -shortis used. Defining this implies -XML_UNICODE.
-
- - XML_LARGE_SIZE -
- If defined, causes the
XML_SizeandXML_Index-integer types to be at least 64 bits in size. This is intended to support -processing of very large input streams, where the return values of -XML_GetCurrentByteIndex, -XML_GetCurrentLineNumberand -XML_GetCurrentColumnNumber-could overflow. It may not be supported by all compilers, and is turned -off by default.
-
- - XML_CONTEXT_BYTES -
- The number of input bytes of markup context which the parser will
-ensure are available for reporting via
XML_GetInputContext. This is -normally set to 1024, and must be set to a positive interger. If this -is not defined, the input context will not be available andXML_GetInputContextwill -always report NULL. Without this, Expat has a smaller memory -footprint and can be faster.
-
- - XML_STATIC -
- On Windows, this should be set if Expat is going to be linked -statically with the code that calls it; this is required to get all -the right MSVC magic annotations correct. This is ignored on other -platforms. - -
- XML_ATTR_INFO -
- If defined, makes the the additional function
XML_GetAttributeInfoavailable -for reporting attribute byte offsets.
-
-
Using Expat
- -Compiling and Linking Against Expat
- -Unless you installed Expat in a location not expected by your
-compiler and linker, all you have to do to use Expat in your programs
-is to include the Expat header (#include <expat.h>)
-in your files that make calls to it and to tell the linker that it
-needs to link against the Expat library. On Unix systems, this would
-usually be done with the -lexpat argument. Otherwise,
-you'll need to tell the compiler where to look for the Expat header
-and the linker where to find the Expat library. You may also need to
-take steps to tell the operating system where to find this library at
-run time.
On a Unix-based system, here's what a Makefile might look like when -Expat is installed in a standard location:
- --CC=cc -LDFLAGS= -LIBS= -lexpat -xmlapp: xmlapp.o - $(CC) $(LDFLAGS) -o xmlapp xmlapp.o $(LIBS) -- -
If you installed Expat in, say, /home/me/mystuff, then
-the Makefile would look like this:
-CC=cc -CFLAGS= -I/home/me/mystuff/include -LDFLAGS= -LIBS= -L/home/me/mystuff/lib -lexpat -xmlapp: xmlapp.o - $(CC) $(LDFLAGS) -o xmlapp xmlapp.o $(LIBS) -- -
You'd also have to set the environment variable
-LD_LIBRARY_PATH to /home/me/mystuff/lib (or
-to ${LD_LIBRARY_PATH}:/home/me/mystuff/lib if
-LD_LIBRARY_PATH already has some directories in it) in order to run
-your application.
Expat Basics
- -As we saw in the example in the overview, the first step in parsing
-an XML document with Expat is to create a parser object. There are three functions in the Expat API for creating a
-parser object. However, only two of these (XML_ParserCreate and XML_ParserCreateNS) can be used for
-constructing a parser for a top-level document. The object returned
-by these functions is an opaque pointer (i.e. "expat.h" declares it as
-void *) to data with further internal structure. In order to free the
-memory associated with this object you must call XML_ParserFree. Note that if you have
-provided any user data that gets stored in the
-parser, then your application is responsible for freeing it prior to
-calling XML_ParserFree.
The objects returned by the parser creation functions are good for -parsing only one XML document or external parsed entity. If your -application needs to parse many XML documents, then it needs to create -a parser object for each one. The best way to deal with this is to -create a higher level object that contains all the default -initialization you want for your parser objects.
- -Walking through a document hierarchy with a stream oriented parser -will require a good stack mechanism in order to keep track of current -context. For instance, to answer the simple question, "What element -does this text belong to?" requires a stack, since the parser may have -descended into other elements that are children of the current one and -has encountered this text on the way out.
- -The things you're likely to want to keep on a stack are the -currently opened element and it's attributes. You push this -information onto the stack in the start handler and you pop it off in -the end handler.
- -For some tasks, it is sufficient to just keep information on what -the depth of the stack is (or would be if you had one.) The outline -program shown above presents one example. Another such task would be -skipping over a complete element. When you see the start tag for the -element you want to skip, you set a skip flag and record the depth at -which the element started. When the end tag handler encounters the -same depth, the skipped element has ended and the flag may be -cleared. If you follow the convention that the root element starts at -1, then you can use the same variable for skip flag and skip -depth.
- -
-void
-init_info(Parseinfo *info) {
- info->skip = 0;
- info->depth = 1;
- /* Other initializations here */
-} /* End of init_info */
-
-void XMLCALL
-rawstart(void *data, const char *el, const char **attr) {
- Parseinfo *inf = (Parseinfo *) data;
-
- if (! inf->skip) {
- if (should_skip(inf, el, attr)) {
- inf->skip = inf->depth;
- }
- else
- start(inf, el, attr); /* This does rest of start handling */
- }
-
- inf->depth++;
-} /* End of rawstart */
-
-void XMLCALL
-rawend(void *data, const char *el) {
- Parseinfo *inf = (Parseinfo *) data;
-
- inf->depth--;
-
- if (! inf->skip)
- end(inf, el); /* This does rest of end handling */
-
- if (inf->skip == inf->depth)
- inf->skip = 0;
-} /* End rawend */
-
-
-Notice in the above example the difference in how depth is -manipulated in the start and end handlers. The end tag handler should -be the mirror image of the start tag handler. This is necessary to -properly model containment. Since, in the start tag handler, we -incremented depth after the main body of start tag code, then -in the end handler, we need to manipulate it before the main -body. If we'd decided to increment it first thing in the start -handler, then we'd have had to decrement it last thing in the end -handler.
- -Communicating between handlers
- -In order to be able to pass information between different handlers
-without using globals, you'll need to define a data structure to hold
-the shared variables. You can then tell Expat (with the XML_SetUserData function) to pass a
-pointer to this structure to the handlers. This is the first
-argument received by most handlers. In the reference section, an argument to a callback function is named
-userData and have type void * if the user
-data is passed; it will have the type XML_Parser if the
-parser itself is passed. When the parser is passed, the user data may
-be retrieved using XML_GetUserData.
One common case where multiple calls to a single handler may need
-to communicate using an application data structure is the case when
-content passed to the character data handler (set by XML_SetCharacterDataHandler) needs to be accumulated. A
-common first-time mistake with any of the event-oriented interfaces to
-an XML parser is to expect all the text contained in an element to be
-reported by a single call to the character data handler. Expat, like
-many other XML parsers, reports such data as a sequence of calls;
-there's no way to know when the end of the sequence is reached until a
-different callback is made. A buffer referenced by the user data
-structure proves both an effective and convenient place to accumulate
-character data.
XML Version
- -Expat is an XML 1.0 parser, and as such never complains based on
-the value of the version pseudo-attribute in the XML
-declaration, if present.
If an application needs to check the version number (to support
-alternate processing), it should use the XML_SetXmlDeclHandler function to
-set a handler that uses the information in the XML declaration to
-determine what to do. This example shows how to check that only a
-version number of "1.0" is accepted:
-static int wrong_version;
-static XML_Parser parser;
-
-static void XMLCALL
-xmldecl_handler(void *userData,
- const XML_Char *version,
- const XML_Char *encoding,
- int standalone)
-{
- static const XML_Char Version_1_0[] = {'1', '.', '0', 0};
-
- int i;
-
- for (i = 0; i < (sizeof(Version_1_0) / sizeof(Version_1_0[0])); ++i) {
- if (version[i] != Version_1_0[i]) {
- wrong_version = 1;
- /* also clear all other handlers: */
- XML_SetCharacterDataHandler(parser, NULL);
- ...
- return;
- }
- }
- ...
-}
-
-
-Namespace Processing
- -When the parser is created using the XML_ParserCreateNS, function, Expat
-performs namespace processing. Under namespace processing, Expat
-consumes xmlns and xmlns:... attributes,
-which declare namespaces for the scope of the element in which they
-occur. This means that your start handler will not see these
-attributes. Your application can still be informed of these
-declarations by setting namespace declaration handlers with XML_SetNamespaceDeclHandler.
Element type and attribute names that belong to a given namespace
-are passed to the appropriate handler in expanded form. By default
-this expanded form is a concatenation of the namespace URI, the
-separator character (which is the 2nd argument to XML_ParserCreateNS), and the local
-name (i.e. the part after the colon). Names with undeclared prefixes
-are not well-formed when namespace processing is enabled, and will
-trigger an error. Unprefixed attribute names are never expanded,
-and unprefixed element names are only expanded when they are in the
-scope of a default namespace.
However if XML_SetReturnNSTriplet has been called with a non-zero
-do_nst parameter, then the expanded form for names with
-an explicit prefix is a concatenation of: URI, separator, local name,
-separator, prefix.
You can set handlers for the start of a namespace declaration and
-for the end of a scope of a declaration with the XML_SetNamespaceDeclHandler
-function. The StartNamespaceDeclHandler is called prior to the start
-tag handler and the EndNamespaceDeclHandler is called after the
-corresponding end tag that ends the namespace's scope. The namespace
-start handler gets passed the prefix and URI for the namespace. For a
-default namespace declaration (xmlns='...'), the prefix will be null.
-The URI will be null for the case where the default namespace is being
-unset. The namespace end handler just gets the prefix for the closing
-scope.
These handlers are called for each declaration. So if, for -instance, a start tag had three namespace declarations, then the -StartNamespaceDeclHandler would be called three times before the start -tag handler is called, once for each declaration.
- -Character Encodings
- -While XML is based on Unicode, and every XML processor is required -to recognized UTF-8 and UTF-16 (1 and 2 byte encodings of Unicode), -other encodings may be declared in XML documents or entities. For the -main document, an XML declaration may contain an encoding -declaration:
--<?xml version="1.0" encoding="ISO-8859-2"?> -- -
External parsed entities may begin with a text declaration, which -looks like an XML declaration with just an encoding declaration:
--<?xml encoding="Big5"?> -- -
With Expat, you may also specify an encoding at the time of -creating a parser. This is useful when the encoding information may -come from a source outside the document itself (like a higher level -protocol.)
- -There are four built-in encodings -in Expat:
--
-
- UTF-8 -
- UTF-16 -
- ISO-8859-1 -
- US-ASCII -
Anything else discovered in an encoding declaration or in the
-protocol encoding specified in the parser constructor, triggers a call
-to the UnknownEncodingHandler. This handler gets passed
-the encoding name and a pointer to an XML_Encoding data
-structure. Your handler must fill in this structure and return
-XML_STATUS_OK if it knows how to deal with the
-encoding. Otherwise the handler should return
-XML_STATUS_ERROR. The handler also gets passed a pointer
-to an optional application data structure that you may indicate when
-you set the handler.
Expat places restrictions on character encodings that it can
-support by filling in the XML_Encoding structure.
-include file:
-
-
- Every ASCII character that can appear in a well-formed XML document -must be represented by a single byte, and that byte must correspond to -it's ASCII encoding (except for the characters $@\^'{}~) -
- Characters must be encoded in 4 bytes or less. -
- All characters encoded must have Unicode scalar values less than or -equal to 65535 (0xFFFF)This does not apply to the built-in support -for UTF-16 and UTF-8 -
- No character may be encoded by more that one distinct sequence of -bytes -
XML_Encoding contains an array of integers that
-correspond to the 1st byte of an encoding sequence. If the value in
-the array for a byte is zero or positive, then the byte is a single
-byte encoding that encodes the Unicode scalar value contained in the
-array. A -1 in this array indicates a malformed byte. If the value is
--2, -3, or -4, then the byte is the beginning of a 2, 3, or 4 byte
-sequence respectively. Multi-byte sequences are sent to the convert
-function pointed at in the XML_Encoding structure. This
-function should return the Unicode scalar value for the sequence or -1
-if the sequence is malformed.
One pitfall that novice Expat users are likely to fall into is that -although Expat may accept input in various encodings, the strings that -it passes to the handlers are always encoded in UTF-8 or UTF-16 -(depending on how Expat was compiled). Your application is responsible -for any translation of these strings into other encodings.
- -Handling External Entity References
- -Expat does not read or parse external entities directly. Note that
-any external DTD is a special case of an external entity. If you've
-set no ExternalEntityRefHandler, then external entity
-references are silently ignored. Otherwise, it calls your handler with
-the information needed to read and parse the external entity.
Your handler isn't actually responsible for parsing the entity, but
-it is responsible for creating a subsidiary parser with XML_ExternalEntityParserCreate that will do the job. This
-returns an instance of XML_Parser that has handlers and
-other data structures initialized from the parent parser. You may then
-use XML_Parse or XML_ParseBuffer calls against this
-parser. Since external entities my refer to other external entities,
-your handler should be prepared to be called recursively.
Parsing DTDs
- -In order to parse parameter entities, before starting the parse,
-you must call XML_SetParamEntityParsing with one of the following
-arguments:
-
-
XML_PARAM_ENTITY_PARSING_NEVER
-- Don't parse parameter entities or the external subset -
XML_PARAM_ENTITY_PARSING_UNLESS_STANDALONE
-- Parse parameter entites and the external subset unless
-
standalonewas set to "yes" in the XML declaration.
- XML_PARAM_ENTITY_PARSING_ALWAYS
-- Always parse parameter entities and the external subset -
In order to read an external DTD, you also have to set an external -entity reference handler as described above.
- -Temporarily Stopping Parsing
- -Expat 1.95.8 introduces a new feature: its now possible to stop -parsing temporarily from within a handler function, even if more data -has already been passed into the parser. Applications for this -include
- --
-
- Supporting the XInclude specification. - -
- Delaying further processing until additional information is - available from some other source. - -
- Adjusting processor load as task priorities shift within an - application. - -
- Stopping parsing completely (simply free or reset the parser - instead of resuming in the outer parsing loop). This can be useful - if a application-domain error is found in the XML being parsed or if - the result of the parse is determined not to be useful after - all. -
To take advantage of this feature, the main parsing loop of an -application needs to support this specifically. It cannot be -supported with a parsing loop compatible with Expat 1.95.7 or -earlier (though existing loops will continue to work without -supporting the stop/resume feature).
- -An application that uses this feature for a single parser will have -the rough structure (in pseudo-code):
- -
-fd = open_input()
-p = create_parser()
-
-if parse_xml(p, fd) {
- /* suspended */
-
- int suspended = 1;
-
- while (suspended) {
- do_something_else()
- if ready_to_resume() {
- suspended = continue_parsing(p, fd);
- }
- }
-}
-
-
-An application that may resume any of several parsers based on -input (either from the XML being parsed or some other source) will -certainly have more interesting control structures.
- -This C function could be used for the parse_xml
-function mentioned in the pseudo-code above:
-#define BUFF_SIZE 10240
-
-/* Parse a document from the open file descriptor 'fd' until the parse
- is complete (the document has been completely parsed, or there's
- been an error), or the parse is stopped. Return non-zero when
- the parse is merely suspended.
-*/
-int
-parse_xml(XML_Parser p, int fd)
-{
- for (;;) {
- int last_chunk;
- int bytes_read;
- enum XML_Status status;
-
- void *buff = XML_GetBuffer(p, BUFF_SIZE);
- if (buff == NULL) {
- /* handle error... */
- return 0;
- }
- bytes_read = read(fd, buff, BUFF_SIZE);
- if (bytes_read < 0) {
- /* handle error... */
- return 0;
- }
- status = XML_ParseBuffer(p, bytes_read, bytes_read == 0);
- switch (status) {
- case XML_STATUS_ERROR:
- /* handle error... */
- return 0;
- case XML_STATUS_SUSPENDED:
- return 1;
- }
- if (bytes_read == 0)
- return 0;
- }
-}
-
-
-The corresponding continue_parsing function is
-somewhat simpler, since it only need deal with the return code from
-XML_ResumeParser; it can
-delegate the input handling to the parse_xml
-function:
-/* Continue parsing a document which had been suspended. The 'p' and
- 'fd' arguments are the same as passed to parse_xml(). Return
- non-zero when the parse is suspended.
-*/
-int
-continue_parsing(XML_Parser p, int fd)
-{
- enum XML_Status status = XML_ResumeParser(p);
- switch (status) {
- case XML_STATUS_ERROR:
- /* handle error... */
- return 0;
- case XML_ERROR_NOT_SUSPENDED:
- /* handle error... */
- return 0;.
- case XML_STATUS_SUSPENDED:
- return 1;
- }
- return parse_xml(p, fd);
-}
-
-
-Now that we've seen what a mess the top-level parsing loop can
-become, what have we gained? Very simply, we can now use the XML_StopParser function to stop
-parsing, without having to go to great lengths to avoid additional
-processing that we're expecting to ignore. As a bonus, we get to stop
-parsing temporarily, and come back to it when we're
-ready.
To stop parsing from a handler function, use the XML_StopParser function. This function
-takes two arguments; the parser being stopped and a flag indicating
-whether the parse can be resumed in the future.
- - -
Expat Reference
- -Parser Creation
- --XML_Parser XMLCALL -XML_ParserCreate(const XML_Char *encoding); --
-
-
- US-ASCII -
- UTF-8 -
- UTF-16 -
- ISO-8859-1 -
-XML_Parser XMLCALL -XML_ParserCreateNS(const XML_Char *encoding, - XML_Char sep); --
'\xFF' is not legal in UTF-8, and
-'\xFFFF' is not legal in UTF-16. There is a special case when
-sep is the null character '\0': the namespace URI and
-the local part will be concatenated without any separator - this is intended
-to support RDF processors. It is a programming error to use the null separator
-with namespace triplets.-XML_Parser XMLCALL -XML_ParserCreate_MM(const XML_Char *encoding, - const XML_Memory_Handling_Suite *ms, - const XML_Char *sep); --
-typedef struct {
- void *(XMLCALL *malloc_fcn)(size_t size);
- void *(XMLCALL *realloc_fcn)(void *ptr, size_t size);
- void (XMLCALL *free_fcn)(void *ptr);
-} XML_Memory_Handling_Suite;
-
-Construct a new parser using the suite of memory handling functions
-specified in ms. If ms is NULL, then use the
-standard set of memory management functions. If sep is
-non NULL, then namespace processing is enabled in the created parser
-and the character pointed at by sep is used as the separator between
-the namespace URI and the local part of the name.
-XML_Parser XMLCALL -XML_ExternalEntityParserCreate(XML_Parser p, - const XML_Char *context, - const XML_Char *encoding); --
XML_Parser object for parsing an external
-general entity. Context is the context argument passed in a call to a
-ExternalEntityRefHandler. Other state information such as handlers,
-user data, namespace processing is inherited from the parser passed as
-the 1st argument. So you shouldn't need to call any of the behavior
-changing functions on this parser (unless you want it to act
-differently than the parent parser).
--void XMLCALL -XML_ParserFree(XML_Parser p); --
-XML_Bool XMLCALL -XML_ParserReset(XML_Parser p, - const XML_Char *encoding); --
parser is
-ready to start parsing a new document. All handlers are cleared from
-the parser, except for the unknownEncodingHandler. The parser's external
-state is re-initialized except for the values of ns and ns_triplets.
-This function may not be used on a parser created using XML_ExternalEntityParserCreate; it will return XML_FALSE in that case. Returns
-XML_TRUE on success. Your application is responsible for
-dealing with any memory associated with user data.
-Parsing
- -To state the obvious: the three parsing functions XML_Parse,
-XML_ParseBuffer and
-XML_GetBuffer must not be called from within a handler
-unless they operate on a separate parser instance, that is, one that
-did not call the handler. For example, it is OK to call the parsing
-functions from within an XML_ExternalEntityRefHandler,
-if they apply to the parser created by
-XML_ExternalEntityParserCreate.
Note: the len argument passed to these functions
-should be considerably less than the maximum value for an integer,
-as it could create an integer overflow situation if the added
-lengths of a buffer and the unprocessed portion of the previous buffer
-exceed the maximum integer value. Input data at the end of a buffer
-will remain unprocessed if it is part of an XML token for which the
-end is not part of that buffer.
-enum XML_Status XMLCALL -XML_Parse(XML_Parser p, - const char *s, - int len, - int isFinal); --
-enum XML_Status {
- XML_STATUS_ERROR = 0,
- XML_STATUS_OK = 1
-};
-
-s is a buffer
-containing part (or perhaps all) of the document. The number of bytes of s
-that are part of the document is indicated by len. This means
-that s doesn't have to be null terminated. It also means that
-if len is larger than the number of bytes in the block of
-memory that s points at, then a memory fault is likely. The
-isFinal parameter informs the parser that this is the last
-piece of the document. Frequently, the last piece is empty (i.e.
-len is zero.)
-If a parse error occurred, it returns XML_STATUS_ERROR.
-Otherwise it returns XML_STATUS_OK value.
--enum XML_Status XMLCALL -XML_ParseBuffer(XML_Parser p, - int len, - int isFinal); --
XML_Parse,
-except in this case Expat provides the buffer. By obtaining the
-buffer from Expat with the XML_GetBuffer function, the application can avoid double
-copying of the input.
--void * XMLCALL -XML_GetBuffer(XML_Parser p, - int len); --
len to read a piece of the document
-into. A NULL value is returned if Expat can't allocate enough memory for
-this buffer. This has to be called prior to every call to
-XML_ParseBuffer. A
-typical use would look like this:
-
-
-for (;;) {
- int bytes_read;
- void *buff = XML_GetBuffer(p, BUFF_SIZE);
- if (buff == NULL) {
- /* handle error */
- }
-
- bytes_read = read(docfd, buff, BUFF_SIZE);
- if (bytes_read < 0) {
- /* handle error */
- }
-
- if (! XML_ParseBuffer(p, bytes_read, bytes_read == 0)) {
- /* handle parse error */
- }
-
- if (bytes_read == 0)
- break;
-}
-
--enum XML_Status XMLCALL -XML_StopParser(XML_Parser p, - XML_Bool resumable); --
Stops parsing, causing XML_Parse or XML_ParseBuffer to return. Must be called from within a
-call-back handler, except when aborting (when resumable
-is XML_FALSE) an already suspended parser. Some
-call-backs may still follow because they would otherwise get
-lost, including
-
-
-
- the end element handler for empty elements when stopped in the - start element handler, -
- the end namespace declaration handler when stopped in the end - element handler, -
- the character data handler when stopped in the character data handler - while making multiple call-backs on a contiguous chunk of characters, -
This can be called from most handlers, including DTD related
-call-backs, except when parsing an external parameter entity and
-resumable is XML_TRUE. Returns
-XML_STATUS_OK when successful,
-XML_STATUS_ERROR otherwise. The possible error codes
-are:
-
-
XML_ERROR_SUSPENDED
- - when suspending an already suspended parser. -
XML_ERROR_FINISHED
- - when the parser has already finished. -
XML_ERROR_SUSPEND_PE
- - when suspending while parsing an external PE. -
Since the stop/resume feature requires application support in the -outer parsing loop, it is an error to call this function for a parser -not being handled appropriately; see Temporarily Stopping Parsing for more information.
- -When resumable is XML_TRUE then parsing
-is suspended, that is, XML_Parse and XML_ParseBuffer return XML_STATUS_SUSPENDED.
-Otherwise, parsing is aborted, that is, XML_Parse and XML_ParseBuffer return
-XML_STATUS_ERROR with error code
-XML_ERROR_ABORTED.
Note:
-This will be applied to the current parser instance only, that is, if
-there is a parent parser then it will continue parsing when the
-external entity reference handler returns. It is up to the
-implementation of that handler to call XML_StopParser on the parent parser
-(recursively), if one wants to stop parsing altogether.
When suspended, parsing can be resumed by calling XML_ResumeParser.
New in Expat 1.95.8.
--enum XML_Status XMLCALL -XML_ResumeParser(XML_Parser p); --
Resumes parsing after it has been suspended with XML_StopParser. Must not be called from
-within a handler call-back. Returns same status codes as XML_Parse or XML_ParseBuffer. An additional error
-code, XML_ERROR_NOT_SUSPENDED, will be returned if the
-parser was not currently suspended.
Note:
-This must be called on the most deeply nested child parser instance
-first, and on its parent parser only after the child parser has
-finished, to be applied recursively until the document entity's parser
-is restarted. That is, the parent parser will not resume by itself
-and it is up to the application to call XML_ResumeParser on it at the
-appropriate moment.
New in Expat 1.95.8.
--void XMLCALL -XML_GetParsingStatus(XML_Parser p, - XML_ParsingStatus *status); --
-enum XML_Parsing {
- XML_INITIALIZED,
- XML_PARSING,
- XML_FINISHED,
- XML_SUSPENDED
-};
-
-typedef struct {
- enum XML_Parsing parsing;
- XML_Bool finalBuffer;
-} XML_ParsingStatus;
-
-Returns status of parser with respect to being initialized,
-parsing, finished, or suspended, and whether the final buffer is being
-processed. The status parameter must not be
-NULL.
New in Expat 1.95.8.
-Handler Setting
- -Although handlers are typically set prior to parsing and left alone, an
-application may choose to set or change the handler for a parsing event
-while the parse is in progress. For instance, your application may choose
-to ignore all text not descended from a para element. One
-way it could do this is to set the character handler when a para start tag
-is seen, and unset it for the corresponding end tag.
A handler may be unset by providing a NULL pointer to the -appropriate handler setter. None of the handler setting functions have -a return value.
- -Your handlers will be receiving strings in arrays of type
-XML_Char. This type is conditionally defined in expat.h as
-either char, wchar_t or unsigned short.
-The former implies UTF-8 encoding, the latter two imply UTF-16 encoding.
-Note that you'll receive them in this form independent of the original
-encoding of the document.
-void XMLCALL -XML_SetStartElementHandler(XML_Parser p, - XML_StartElementHandler start); --
-typedef void -(XMLCALL *XML_StartElementHandler)(void *userData, - const XML_Char *name, - const XML_Char **atts); --
Set handler for start (and empty) tags. Attributes are passed to the start -handler as a pointer to a vector of char pointers. Each attribute seen in -a start (or empty) tag occupies 2 consecutive places in this vector: the -attribute name followed by the attribute value. These pairs are terminated -by a null pointer.
-Note that an empty tag generates a call to both start and end handlers -(in that order).
--void XMLCALL -XML_SetEndElementHandler(XML_Parser p, - XML_EndElementHandler); --
-typedef void -(XMLCALL *XML_EndElementHandler)(void *userData, - const XML_Char *name); --
Set handler for end (and empty) tags. As noted above, an empty tag -generates a call to both start and end handlers.
--void XMLCALL -XML_SetElementHandler(XML_Parser p, - XML_StartElementHandler start, - XML_EndElementHandler end); --
Set handlers for start and end tags with one call.
--void XMLCALL -XML_SetCharacterDataHandler(XML_Parser p, - XML_CharacterDataHandler charhndl) --
-typedef void -(XMLCALL *XML_CharacterDataHandler)(void *userData, - const XML_Char *s, - int len); --
Set a text handler. The string your handler receives -is NOT nul-terminated. You have to use the length argument -to deal with the end of the string. A single block of contiguous text -free of markup may still result in a sequence of calls to this handler. -In other words, if you're searching for a pattern in the text, it may -be split across calls to this handler. Note: Setting this handler to NULL -may NOT immediately terminate call-backs if the parser is currently -processing such a single block of contiguous markup-free text, as the parser -will continue calling back until the end of the block is reached.
--void XMLCALL -XML_SetProcessingInstructionHandler(XML_Parser p, - XML_ProcessingInstructionHandler proc) --
-typedef void -(XMLCALL *XML_ProcessingInstructionHandler)(void *userData, - const XML_Char *target, - const XML_Char *data); - --
Set a handler for processing instructions. The target is the first word -in the processing instruction. The data is the rest of the characters in -it after skipping all whitespace after the initial word.
--void XMLCALL -XML_SetCommentHandler(XML_Parser p, - XML_CommentHandler cmnt) --
-typedef void -(XMLCALL *XML_CommentHandler)(void *userData, - const XML_Char *data); --
Set a handler for comments. The data is all text inside the comment -delimiters.
--void XMLCALL -XML_SetStartCdataSectionHandler(XML_Parser p, - XML_StartCdataSectionHandler start); --
-typedef void -(XMLCALL *XML_StartCdataSectionHandler)(void *userData); --
Set a handler that gets called at the beginning of a CDATA section.
--void XMLCALL -XML_SetEndCdataSectionHandler(XML_Parser p, - XML_EndCdataSectionHandler end); --
-typedef void -(XMLCALL *XML_EndCdataSectionHandler)(void *userData); --
Set a handler that gets called at the end of a CDATA section.
--void XMLCALL -XML_SetCdataSectionHandler(XML_Parser p, - XML_StartCdataSectionHandler start, - XML_EndCdataSectionHandler end) --
Sets both CDATA section handlers with one call.
--void XMLCALL -XML_SetDefaultHandler(XML_Parser p, - XML_DefaultHandler hndl) --
-typedef void -(XMLCALL *XML_DefaultHandler)(void *userData, - const XML_Char *s, - int len); -- -
Sets a handler for any characters in the document which wouldn't -otherwise be handled. This includes both data for which no handlers -can be set (like some kinds of DTD declarations) and data which could -be reported but which currently has no handler set. The characters -are passed exactly as they were present in the XML document except -that they will be encoded in UTF-8 or UTF-16. Line boundaries are not -normalized. Note that a byte order mark character is not passed to the -default handler. There are no guarantees about how characters are -divided between calls to the default handler: for example, a comment -might be split between multiple calls. Setting the handler with -this call has the side effect of turning off expansion of references -to internally defined general entities. Instead these references are -passed to the default handler.
- -See also XML_DefaultCurrent.
-void XMLCALL -XML_SetDefaultHandlerExpand(XML_Parser p, - XML_DefaultHandler hndl) --
-typedef void -(XMLCALL *XML_DefaultHandler)(void *userData, - const XML_Char *s, - int len); --
This sets a default handler, but doesn't inhibit the expansion of -internal entity references. The entity reference will not be passed -to the default handler.
- -See also XML_DefaultCurrent.
-void XMLCALL -XML_SetExternalEntityRefHandler(XML_Parser p, - XML_ExternalEntityRefHandler hndl) --
-typedef int -(XMLCALL *XML_ExternalEntityRefHandler)(XML_Parser p, - const XML_Char *context, - const XML_Char *base, - const XML_Char *systemId, - const XML_Char *publicId); --
Set an external entity reference handler. This handler is also
-called for processing an external DTD subset if parameter entity parsing
-is in effect. (See
-XML_SetParamEntityParsing.)
The context parameter specifies the parsing context in
-the format expected by the context argument to XML_ExternalEntityParserCreate. code is
-valid only until the handler returns, so if the referenced entity is
-to be parsed later, it must be copied. context is NULL
-only when the entity is a parameter entity, which is how one can
-differentiate between general and parameter entities.
The base parameter is the base to use for relative
-system identifiers. It is set by XML_SetBase and may be NULL. The
-publicId parameter is the public id given in the entity
-declaration and may be NULL. systemId is the system
-identifier specified in the entity declaration and is never NULL.
There are a couple of ways in which this handler differs from
-others. First, this handler returns a status indicator (an
-integer). XML_STATUS_OK should be returned for successful
-handling of the external entity reference. Returning
-XML_STATUS_ERROR indicates failure, and causes the
-calling parser to return an
-XML_ERROR_EXTERNAL_ENTITY_HANDLING error.
Second, instead of having the user data as its first argument, it
-receives the parser that encountered the entity reference. This, along
-with the context parameter, may be used as arguments to a call to
-XML_ExternalEntityParserCreate. Using the returned
-parser, the body of the external entity can be recursively parsed.
Since this handler may be called recursively, it should not be saving -information into global or static variables.
--void XMLCALL -XML_SetExternalEntityRefHandlerArg(XML_Parser p, - void *arg) --
Set the argument passed to the ExternalEntityRefHandler. If
-arg is not NULL, it is the new value passed to the
-handler set using XML_SetExternalEntityRefHandler; if arg is
-NULL, the argument passed to the handler function will be the parser
-object itself.
Note:
-The type of arg and the type of the first argument to the
-ExternalEntityRefHandler do not match. This function takes a
-void * to be passed to the handler, while the handler
-accepts an XML_Parser. This is a historical accident,
-but will not be corrected before Expat 2.0 (at the earliest) to avoid
-causing compiler warnings for code that's known to work with this
-API. It is the responsibility of the application code to know the
-actual type of the argument passed to the handler and to manage it
-properly.
-void XMLCALL -XML_SetSkippedEntityHandler(XML_Parser p, - XML_SkippedEntityHandler handler) --
-typedef void -(XMLCALL *XML_SkippedEntityHandler)(void *userData, - const XML_Char *entityName, - int is_parameter_entity); --
Set a skipped entity handler. This is called in two situations:
--
-
- An entity reference is encountered for which no declaration - has been read and this is not an error. -
- An internal entity reference is read, but not expanded, because
-
XML_SetDefaultHandler- has been called.
-
The is_parameter_entity argument will be non-zero for
-a parameter entity and zero for a general entity.
Note: skipped -parameter entities in declarations and skipped general entities in -attribute values cannot be reported, because the event would be out of -sync with the reporting of the declarations or attribute values
--void XMLCALL -XML_SetUnknownEncodingHandler(XML_Parser p, - XML_UnknownEncodingHandler enchandler, - void *encodingHandlerData) --
-typedef int
-(XMLCALL *XML_UnknownEncodingHandler)(void *encodingHandlerData,
- const XML_Char *name,
- XML_Encoding *info);
-
-typedef struct {
- int map[256];
- void *data;
- int (XMLCALL *convert)(void *data, const char *s);
- void (XMLCALL *release)(void *data);
-} XML_Encoding;
-
-Set a handler to deal with encodings other than the built in set. This should be done before
-XML_Parse or XML_ParseBuffer have been called on the
-given parser.
If the handler knows how to deal with an encoding
-with the given name, it should fill in the info data
-structure and return XML_STATUS_OK. Otherwise it
-should return XML_STATUS_ERROR. The handler will be called
-at most once per parsed (external) entity. The optional application
-data pointer encodingHandlerData will be passed back to
-the handler.
The map array contains information for every possible possible leading
-byte in a byte sequence. If the corresponding value is >= 0, then it's
-a single byte sequence and the byte encodes that Unicode value. If the
-value is -1, then that byte is invalid as the initial byte in a sequence.
-If the value is -n, where n is an integer > 1, then n is the number of
-bytes in the sequence and the actual conversion is accomplished by a
-call to the function pointed at by convert. This function may return -1
-if the sequence itself is invalid. The convert pointer may be null if
-there are only single byte codes. The data parameter passed to the convert
-function is the data pointer from XML_Encoding. The
-string s is NOT nul-terminated and points at the sequence of
-bytes to be converted.
The function pointed at by release is called by the
-parser when it is finished with the encoding. It may be NULL.
-void XMLCALL -XML_SetStartNamespaceDeclHandler(XML_Parser p, - XML_StartNamespaceDeclHandler start); --
-typedef void -(XMLCALL *XML_StartNamespaceDeclHandler)(void *userData, - const XML_Char *prefix, - const XML_Char *uri); --
Set a handler to be called when a namespace is declared. Namespace -declarations occur inside start tags. But the namespace declaration start -handler is called before the start tag handler for each namespace declared -in that start tag.
--void XMLCALL -XML_SetEndNamespaceDeclHandler(XML_Parser p, - XML_EndNamespaceDeclHandler end); --
-typedef void -(XMLCALL *XML_EndNamespaceDeclHandler)(void *userData, - const XML_Char *prefix); --
Set a handler to be called when leaving the scope of a namespace -declaration. This will be called, for each namespace declaration, -after the handler for the end tag of the element in which the -namespace was declared.
--void XMLCALL -XML_SetNamespaceDeclHandler(XML_Parser p, - XML_StartNamespaceDeclHandler start, - XML_EndNamespaceDeclHandler end) --
Sets both namespace declaration handlers with a single call.
--void XMLCALL -XML_SetXmlDeclHandler(XML_Parser p, - XML_XmlDeclHandler xmldecl); --
-typedef void -(XMLCALL *XML_XmlDeclHandler)(void *userData, - const XML_Char *version, - const XML_Char *encoding, - int standalone); --
Sets a handler that is called for XML declarations and also for
-text declarations discovered in external entities. The way to
-distinguish is that the version parameter will be NULL
-for text declarations. The encoding parameter may be NULL
-for an XML declaration. The standalone argument will
-contain -1, 0, or 1 indicating respectively that there was no
-standalone parameter in the declaration, that it was given as no, or
-that it was given as yes.
-void XMLCALL -XML_SetStartDoctypeDeclHandler(XML_Parser p, - XML_StartDoctypeDeclHandler start); --
-typedef void -(XMLCALL *XML_StartDoctypeDeclHandler)(void *userData, - const XML_Char *doctypeName, - const XML_Char *sysid, - const XML_Char *pubid, - int has_internal_subset); --
Set a handler that is called at the start of a DOCTYPE declaration,
-before any external or internal subset is parsed. Both sysid
-and pubid may be NULL. The has_internal_subset
-will be non-zero if the DOCTYPE declaration has an internal subset.
-void XMLCALL -XML_SetEndDoctypeDeclHandler(XML_Parser p, - XML_EndDoctypeDeclHandler end); --
-typedef void -(XMLCALL *XML_EndDoctypeDeclHandler)(void *userData); --
Set a handler that is called at the end of a DOCTYPE declaration, -after parsing any external subset.
--void XMLCALL -XML_SetDoctypeDeclHandler(XML_Parser p, - XML_StartDoctypeDeclHandler start, - XML_EndDoctypeDeclHandler end); --
Set both doctype handlers with one call.
--void XMLCALL -XML_SetElementDeclHandler(XML_Parser p, - XML_ElementDeclHandler eldecl); --
-typedef void -(XMLCALL *XML_ElementDeclHandler)(void *userData, - const XML_Char *name, - XML_Content *model); --
-enum XML_Content_Type {
- XML_CTYPE_EMPTY = 1,
- XML_CTYPE_ANY,
- XML_CTYPE_MIXED,
- XML_CTYPE_NAME,
- XML_CTYPE_CHOICE,
- XML_CTYPE_SEQ
-};
-
-enum XML_Content_Quant {
- XML_CQUANT_NONE,
- XML_CQUANT_OPT,
- XML_CQUANT_REP,
- XML_CQUANT_PLUS
-};
-
-typedef struct XML_cp XML_Content;
-
-struct XML_cp {
- enum XML_Content_Type type;
- enum XML_Content_Quant quant;
- const XML_Char * name;
- unsigned int numchildren;
- XML_Content * children;
-};
-
-Sets a handler for element declarations in a DTD. The handler gets
-called with the name of the element in the declaration and a pointer
-to a structure that contains the element model. It is the
-application's responsibility to free this data structure using
-XML_FreeContentModel.
The model argument is the root of a tree of
-XML_Content nodes. If type equals
-XML_CTYPE_EMPTY or XML_CTYPE_ANY, then
-quant will be XML_CQUANT_NONE, and the other
-fields will be zero or NULL. If type is
-XML_CTYPE_MIXED, then quant will be
-XML_CQUANT_NONE or XML_CQUANT_REP and
-numchildren will contain the number of elements that are
-allowed to be mixed in and children points to an array of
-XML_Content structures that will all have type
-XML_CTYPE_NAME with no quantification. Only the root node can be type
-XML_CTYPE_EMPTY, XML_CTYPE_ANY, or
-XML_CTYPE_MIXED.
For type XML_CTYPE_NAME, the name field
-points to the name and the numchildren and
-children fields will be zero and NULL. The
-quant field will indicate any quantifiers placed on the
-name.
Types XML_CTYPE_CHOICE and XML_CTYPE_SEQ
-indicate a choice or sequence respectively. The
-numchildren field indicates how many nodes in the choice
-or sequence and children points to the nodes.
-void XMLCALL -XML_SetAttlistDeclHandler(XML_Parser p, - XML_AttlistDeclHandler attdecl); --
-typedef void -(XMLCALL *XML_AttlistDeclHandler)(void *userData, - const XML_Char *elname, - const XML_Char *attname, - const XML_Char *att_type, - const XML_Char *dflt, - int isrequired); --
Set a handler for attlist declarations in the DTD. This handler is
-called for each attribute. So a single attlist declaration
-with multiple attributes declared will generate multiple calls to this
-handler. The elname parameter returns the name of the
-element for which the attribute is being declared. The attribute name
-is in the attname parameter. The attribute type is in the
-att_type parameter. It is the string representing the
-type in the declaration with whitespace removed.
The dflt parameter holds the default value. It will be
-NULL in the case of "#IMPLIED" or "#REQUIRED" attributes. You can
-distinguish these two cases by checking the isrequired
-parameter, which will be true in the case of "#REQUIRED" attributes.
-Attributes which are "#FIXED" will have also have a true
-isrequired, but they will have the non-NULL fixed value
-in the dflt parameter.
-void XMLCALL -XML_SetEntityDeclHandler(XML_Parser p, - XML_EntityDeclHandler handler); --
-typedef void -(XMLCALL *XML_EntityDeclHandler)(void *userData, - const XML_Char *entityName, - int is_parameter_entity, - const XML_Char *value, - int value_length, - const XML_Char *base, - const XML_Char *systemId, - const XML_Char *publicId, - const XML_Char *notationName); --
Sets a handler that will be called for all entity declarations.
-The is_parameter_entity argument will be non-zero in the
-case of parameter entities and zero otherwise.
For internal entities (<!ENTITY foo "bar">),
-value will be non-NULL and systemId,
-publicId, and notationName will all be NULL.
-The value string is not NULL terminated; the length is
-provided in the value_length parameter. Do not use
-value_length to test for internal entities, since it is
-legal to have zero-length values. Instead check for whether or not
-value is NULL.
The notationName
-argument will have a non-NULL value only for unparsed entity
-declarations.
-void XMLCALL -XML_SetUnparsedEntityDeclHandler(XML_Parser p, - XML_UnparsedEntityDeclHandler h) --
-typedef void -(XMLCALL *XML_UnparsedEntityDeclHandler)(void *userData, - const XML_Char *entityName, - const XML_Char *base, - const XML_Char *systemId, - const XML_Char *publicId, - const XML_Char *notationName); --
Set a handler that receives declarations of unparsed entities. These -are entity declarations that have a notation (NDATA) field:
- --<!ENTITY logo SYSTEM "images/logo.gif" NDATA gif> -
This handler is obsolete and is provided for backwards -compatibility. Use instead XML_SetEntityDeclHandler.
--void XMLCALL -XML_SetNotationDeclHandler(XML_Parser p, - XML_NotationDeclHandler h) --
-typedef void -(XMLCALL *XML_NotationDeclHandler)(void *userData, - const XML_Char *notationName, - const XML_Char *base, - const XML_Char *systemId, - const XML_Char *publicId); --
Set a handler that receives notation declarations.
--void XMLCALL -XML_SetNotStandaloneHandler(XML_Parser p, - XML_NotStandaloneHandler h) --
-typedef int -(XMLCALL *XML_NotStandaloneHandler)(void *userData); --
Set a handler that is called if the document is not "standalone".
-This happens when there is an external subset or a reference to a
-parameter entity, but does not have standalone set to "yes" in an XML
-declaration. If this handler returns XML_STATUS_ERROR,
-then the parser will throw an XML_ERROR_NOT_STANDALONE
-error.
Parse position and error reporting functions
- -These are the functions you'll want to call when the parse
-functions return XML_STATUS_ERROR (a parse error has
-occurred), although the position reporting functions are useful outside
-of errors. The position reported is the byte position (in the original
-document or entity encoding) of the first of the sequence of
-characters that generated the current event (or the error that caused
-the parse functions to return XML_STATUS_ERROR.) The
-exceptions are callbacks trigged by declarations in the document
-prologue, in which case they exact position reported is somewhere in the
-relevant markup, but not necessarily as meaningful as for other
-events.
The position reporting functions are accurate only outside of the -DTD. In other words, they usually return bogus information when -called from within a DTD declaration handler.
- --enum XML_Error XMLCALL -XML_GetErrorCode(XML_Parser p); --
-const XML_LChar * XMLCALL -XML_ErrorString(enum XML_Error code); --
XML_GetErrorCode.
--XML_Index XMLCALL -XML_GetCurrentByteIndex(XML_Parser p); --
XML_GetCurrentLineNumber and XML_GetCurrentColumnNumber.
--XML_Size XMLCALL -XML_GetCurrentLineNumber(XML_Parser p); --
1.
--XML_Size XMLCALL -XML_GetCurrentColumnNumber(XML_Parser p); --
-int XMLCALL -XML_GetCurrentByteCount(XML_Parser p); --
0 if the event is inside a reference to an internal
-entity and for the end-tag event for empty element tags (the later can
-be used to distinguish empty-element tags from empty elements using
-separate start and end tags).
--const char * XMLCALL -XML_GetInputContext(XML_Parser p, - int *offset, - int *size); --
Returns the parser's input buffer, sets the integer pointed at by
-offset to the offset within this buffer of the current
-parse position, and set the integer pointed at by size to
-the size of the returned buffer.
This should only be called from within a handler during an active -parse and the returned buffer should only be referred to from within -the handler that made the call. This input buffer contains the -untranslated bytes of the input.
- -Only a limited amount of context is kept, so if the event -triggering a call spans over a very large amount of input, the actual -parse position may be before the beginning of the buffer.
- -If XML_CONTEXT_BYTES is not defined, this will always
-return NULL.
Miscellaneous functions
- -The functions in this section either obtain state information from -the parser or can be used to dynamicly set parser options.
- --void XMLCALL -XML_SetUserData(XML_Parser p, - void *userData); --
userData when it is finished with the parser. So if you
-call this when there's already a pointer there, and you haven't freed
-the memory associated with it, then you've probably just leaked
-memory.
--void * XMLCALL -XML_GetUserData(XML_Parser p); --
-void XMLCALL -XML_UseParserAsHandlerArg(XML_Parser p); --
userData arguments. The user data can still be obtained
-using the XML_GetUserData function.
--enum XML_Status XMLCALL -XML_SetBase(XML_Parser p, - const XML_Char *base); --
XML_STATUS_ERROR if
-there's no memory to store base, otherwise it's
-XML_STATUS_OK.
--const XML_Char * XMLCALL -XML_GetBase(XML_Parser p); --
-int XMLCALL -XML_GetSpecifiedAttributeCount(XML_Parser p); --
atts array passed to the start tag handler of the first
-attribute set due to defaults. It supplies information for the last
-call to a start handler. If called inside a start handler, then that
-means the current call.
--int XMLCALL -XML_GetIdAttributeIndex(XML_Parser p); --
XML_StartElementHandler, or -1 if there is no ID
-attribute. If called inside a start handler, then that means the
-current call.
--const XML_AttrInfo * XMLCALL -XML_GetAttributeInfo(XML_Parser parser); --
-typedef struct {
- XML_Index nameStart; /* Offset to beginning of the attribute name. */
- XML_Index nameEnd; /* Offset after the attribute name's last byte. */
- XML_Index valueStart; /* Offset to beginning of the attribute value. */
- XML_Index valueEnd; /* Offset after the attribute value's last byte. */
-} XML_AttrInfo;
-
-XML_AttrInfo structures for the
-attribute/value pairs passed in the last call to the
-XML_StartElementHandler that were specified
-in the start-tag rather than defaulted. Each attribute/value pair counts
-as 1; thus the number of entries in the array is
-XML_GetSpecifiedAttributeCount(parser) / 2.
--enum XML_Status XMLCALL -XML_SetEncoding(XML_Parser p, - const XML_Char *encoding); --
XML_Parse or XML_ParseBuffer have been called on the given parser.
-Returns XML_STATUS_OK on success or
-XML_STATUS_ERROR on error.
--int XMLCALL -XML_SetParamEntityParsing(XML_Parser p, - enum XML_ParamEntityParsing code); --
code.
-The choices for code are:
--
-
XML_PARAM_ENTITY_PARSING_NEVER
-XML_PARAM_ENTITY_PARSING_UNLESS_STANDALONE
-XML_PARAM_ENTITY_PARSING_ALWAYS
-
XML_SetParamEntityParsing is called after
-XML_Parse or XML_ParseBuffer, then it has
-no effect and will always return 0.
--int XMLCALL -XML_SetHashSalt(XML_Parser p, - unsigned long hash_salt); --
XML_Parse or XML_ParseBuffer.
-Note:This call is optional, as the parser will auto-generate -a new random salt value if no value has been set at the start of parsing. -
Note:One should not call XML_SetHashSalt with a
-hash salt value of 0, as this value is used as sentinel value to indicate
-that XML_SetHashSalt has not been called. Consequently
-such a call will have no effect, even if it returns 1.
-enum XML_Error XMLCALL -XML_UseForeignDTD(XML_Parser parser, XML_Bool useDTD); --
This function allows an application to provide an external subset
-for the document type declaration for documents which do not specify
-an external subset of their own. For documents which specify an
-external subset in their DOCTYPE declaration, the application-provided
-subset will be ignored. If the document does not contain a DOCTYPE
-declaration at all and useDTD is true, the
-application-provided subset will be parsed, but the
-startDoctypeDeclHandler and
-endDoctypeDeclHandler functions, if set, will not be
-called. The setting of parameter entity parsing, controlled using
-XML_SetParamEntityParsing, will be honored.
The application-provided external subset is read by calling the
-external entity reference handler set via XML_SetExternalEntityRefHandler with both
-publicId and systemId set to NULL.
If this function is called after parsing has begun, it returns
-XML_ERROR_CANT_CHANGE_FEATURE_ONCE_PARSING and ignores
-useDTD. If called when Expat has been compiled without
-DTD support, it returns
-XML_ERROR_FEATURE_REQUIRES_XML_DTD. Otherwise, it
-returns XML_ERROR_NONE.
Note: For the purpose of checking WFC: Entity Declared, passing
-useDTD == XML_TRUE will make the parser behave as if
-the document had a DTD with an external subset. This holds true even if
-the external entity reference handler returns without action.
-void XMLCALL -XML_SetReturnNSTriplet(XML_Parser parser, - int do_nst); --
-This function only has an effect when using a parser created with
-XML_ParserCreateNS,
-i.e. when namespace processing is in effect. The do_nst
-sets whether or not prefixes are returned with names qualified with a
-namespace prefix. If this function is called with do_nst
-non-zero, then afterwards namespace qualified names (that is qualified
-with a prefix as opposed to belonging to a default namespace) are
-returned as a triplet with the three parts separated by the namespace
-separator specified when the parser was created. The order of
-returned parts is URI, local name, and prefix.
If
-do_nst is zero, then namespaces are reported in the
-default manner, URI then local_name separated by the namespace
-separator.
-void XMLCALL -XML_DefaultCurrent(XML_Parser parser); --
XML_SetDefaultHandler or
-XML_SetDefaultHandlerExpand. It does nothing if there is
-not a default handler.
--XML_LChar * XMLCALL -XML_ExpatVersion(); --
"expat_1.95.1").
--struct XML_Expat_Version XMLCALL -XML_ExpatVersionInfo(); --
-typedef struct {
- int major;
- int minor;
- int micro;
-} XML_Expat_Version;
-
--
-
XML_MAJOR_VERSION
-XML_MINOR_VERSION
-XML_MICRO_VERSION
-
-const XML_Feature * XMLCALL -XML_GetFeatureList(); --
-enum XML_FeatureEnum {
- XML_FEATURE_END = 0,
- XML_FEATURE_UNICODE,
- XML_FEATURE_UNICODE_WCHAR_T,
- XML_FEATURE_DTD,
- XML_FEATURE_CONTEXT_BYTES,
- XML_FEATURE_MIN_SIZE,
- XML_FEATURE_SIZEOF_XML_CHAR,
- XML_FEATURE_SIZEOF_XML_LCHAR,
- XML_FEATURE_NS,
- XML_FEATURE_LARGE_SIZE
-};
-
-typedef struct {
- enum XML_FeatureEnum feature;
- XML_LChar *name;
- long int value;
-} XML_Feature;
-
-Returns a list of "feature" records, providing details on how -Expat was configured at compile time. Most applications should not -need to worry about this, but this information is otherwise not -available from Expat. This function allows code that does need to -check these features to do so at runtime.
- -The return value is an array of XML_Feature,
-terminated by a record with a feature of
-XML_FEATURE_END and name of NULL,
-identifying the feature-test macros Expat was compiled with. Since an
-application that requires this kind of information needs to determine
-the type of character the name points to, records for the
-XML_FEATURE_SIZEOF_XML_CHAR and
-XML_FEATURE_SIZEOF_XML_LCHAR will be located at the
-beginning of the list, followed by XML_FEATURE_UNICODE
-and XML_FEATURE_UNICODE_WCHAR_T, if they are present at
-all.
Some features have an associated value. If there isn't an
-associated value, the value field is set to 0. At this
-time, the following features have been defined to have values:
-
-
XML_FEATURE_SIZEOF_XML_CHAR
- - The number of bytes occupied by one
XML_Char- character.
- XML_FEATURE_SIZEOF_XML_LCHAR
- - The number of bytes occupied by one
XML_LChar- character.
- XML_FEATURE_CONTEXT_BYTES
- - The maximum number of characters of context which can be
- reported by
XML_GetInputContext.
-
-void XMLCALL -XML_FreeContentModel(XML_Parser parser, XML_Content *model); --
model argument passed to the
-XML_ElementDeclHandler callback set using XML_ElementDeclHandler.
-This function should not be used for any other purpose.
-The following functions allow external code to share the memory
-allocator an XML_Parser has been configured to use. This
-is especially useful for third-party libraries that interact with a
-parser object created by application code, or heavily layered
-applications. This can be essential when using dynamically loaded
-libraries which use different C standard libraries (this can happen on
-Windows, at least).
-void * XMLCALL -XML_MemMalloc(XML_Parser parser, size_t size); --
size bytes of memory using the allocator the
-parser object has been configured to use. Returns a
-pointer to the memory or NULL on failure. Memory allocated in this
-way must be freed using XML_MemFree.
--void * XMLCALL -XML_MemRealloc(XML_Parser parser, void *ptr, size_t size); --
size bytes of memory using the allocator the
-parser object has been configured to use.
-ptr must point to a block of memory allocated by XML_MemMalloc or
-XML_MemRealloc, or be NULL. This function tries to
-expand the block pointed to by ptr if possible. Returns
-a pointer to the memory or NULL on failure. On success, the original
-block has either been expanded or freed. On failure, the original
-block has not been freed; the caller is responsible for freeing the
-original block. Memory allocated in this way must be freed using
-XML_MemFree.
--void XMLCALL -XML_MemFree(XML_Parser parser, void *ptr); --
ptr. The block must
-have been allocated by XML_MemMalloc or XML_MemRealloc, or be NULL.
--
