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/**
* section: xmlReader
* synopsis: Show how to extract subdocuments with xmlReader
* purpose: Demonstrate the use of xmlTextReaderPreservePattern()
* to parse an XML file with the xmlReader while collecting
* only some subparts of the document.
* (Note that the XMLReader functions require libxml2 version later
* than 2.6.)
* usage: reader3
* test: reader3 > reader3.tmp ; diff reader3.tmp reader3.res ; rm reader3.tmp
* author: Daniel Veillard
* copy: see Copyright for the status of this software.
*/
#include <stdio.h>
#include <libxml/xmlreader.h>
#if defined(LIBXML_READER_ENABLED) && defined(LIBXML_PATTERN_ENABLED)
/**
* streamFile:
* @filename: the file name to parse
*
* Parse and print information about an XML file.
*
* Returns the resulting doc with just the elements preserved.
*/
static xmlDocPtr
extractFile(const char *filename, const xmlChar *pattern) {
xmlDocPtr doc;
xmlTextReaderPtr reader;
int ret;
/*
* build an xmlReader for that file
*/
reader = xmlReaderForFile(filename, NULL, 0);
if (reader != NULL) {
/*
* add the pattern to preserve
*/
if (xmlTextReaderPreservePattern(reader, pattern, NULL) < 0) {
fprintf(stderr, "%s : failed add preserve pattern %s\n",
filename, (const char *) pattern);
}
/*
* Parse and traverse the tree, collecting the nodes in the process
*/
ret = xmlTextReaderRead(reader);
while (ret == 1) {
ret = xmlTextReaderRead(reader);
}
if (ret != 0) {
fprintf(stderr, "%s : failed to parse\n", filename);
xmlFreeTextReader(reader);
return(NULL);
}
/*
* get the resulting nodes
*/
doc = xmlTextReaderCurrentDoc(reader);
/*
* Free up the reader
*/
xmlFreeTextReader(reader);
} else {
fprintf(stderr, "Unable to open %s\n", filename);
return(NULL);
}
return(doc);
}
int main(int argc, char **argv) {
const char *filename = "test3.xml";
const char *pattern = "preserved";
xmlDocPtr doc;
if (argc == 3) {
filename = argv[1];
pattern = argv[2];
}
/*
* this initialize the library and check potential ABI mismatches
* between the version it was compiled for and the actual shared
* library used.
*/
LIBXML_TEST_VERSION
doc = extractFile(filename, (const xmlChar *) pattern);
if (doc != NULL) {
/*
* ouptut the result.
*/
xmlDocDump(stdout, doc);
/*
* don't forget to free up the doc
*/
xmlFreeDoc(doc);
}
/*
* Cleanup function for the XML library.
*/
xmlCleanupParser();
/*
* this is to debug memory for regression tests
*/
xmlMemoryDump();
return(0);
}
#else
int main(void) {
fprintf(stderr, "Reader or Pattern support not compiled in\n");
exit(1);
}
#endif
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