/** * 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 $(srcdir)/reader3.res * 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) && defined(LIBXML_OUTPUT_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) { /* * output 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, Pattern or output support not compiled in\n"); exit(1); } #endif