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Annotation of embedaddon/libxml2/doc/examples/reader3.c, revision 1.1.1.1

1.1       misho       1: /**
                      2:  * section: xmlReader
                      3:  * synopsis: Show how to extract subdocuments with xmlReader
                      4:  * purpose: Demonstrate the use of xmlTextReaderPreservePattern() 
                      5:  *          to parse an XML file with the xmlReader while collecting
                      6:  *          only some subparts of the document.
                      7:  *          (Note that the XMLReader functions require libxml2 version later
                      8:  *          than 2.6.)
                      9:  * usage: reader3
                     10:  * test: reader3 > reader3.tmp ; diff reader3.tmp reader3.res ; rm reader3.tmp
                     11:  * author: Daniel Veillard
                     12:  * copy: see Copyright for the status of this software.
                     13:  */
                     14: 
                     15: #include <stdio.h>
                     16: #include <libxml/xmlreader.h>
                     17: 
                     18: #if defined(LIBXML_READER_ENABLED) && defined(LIBXML_PATTERN_ENABLED) && defined(LIBXML_OUTPUT_ENABLED)
                     19: 
                     20: 
                     21: /**
                     22:  * streamFile:
                     23:  * @filename: the file name to parse
                     24:  *
                     25:  * Parse and print information about an XML file.
                     26:  *
                     27:  * Returns the resulting doc with just the elements preserved.
                     28:  */
                     29: static xmlDocPtr
                     30: extractFile(const char *filename, const xmlChar *pattern) {
                     31:     xmlDocPtr doc;
                     32:     xmlTextReaderPtr reader;
                     33:     int ret;
                     34: 
                     35:     /*
                     36:      * build an xmlReader for that file
                     37:      */
                     38:     reader = xmlReaderForFile(filename, NULL, 0);
                     39:     if (reader != NULL) {
                     40:         /*
                     41:         * add the pattern to preserve
                     42:         */
                     43:         if (xmlTextReaderPreservePattern(reader, pattern, NULL) < 0) {
                     44:             fprintf(stderr, "%s : failed add preserve pattern %s\n",
                     45:                    filename, (const char *) pattern);
                     46:        }
                     47:        /*
                     48:         * Parse and traverse the tree, collecting the nodes in the process
                     49:         */
                     50:         ret = xmlTextReaderRead(reader);
                     51:         while (ret == 1) {
                     52:             ret = xmlTextReaderRead(reader);
                     53:         }
                     54:         if (ret != 0) {
                     55:             fprintf(stderr, "%s : failed to parse\n", filename);
                     56:            xmlFreeTextReader(reader);
                     57:            return(NULL);
                     58:         }
                     59:        /*
                     60:         * get the resulting nodes
                     61:         */
                     62:        doc = xmlTextReaderCurrentDoc(reader);
                     63:        /*
                     64:         * Free up the reader
                     65:         */
                     66:         xmlFreeTextReader(reader);
                     67:     } else {
                     68:         fprintf(stderr, "Unable to open %s\n", filename);
                     69:        return(NULL);
                     70:     }
                     71:     return(doc);
                     72: }
                     73: 
                     74: int main(int argc, char **argv) {
                     75:     const char *filename = "test3.xml";
                     76:     const char *pattern = "preserved";
                     77:     xmlDocPtr doc;
                     78: 
                     79:     if (argc == 3) {
                     80:         filename = argv[1];
                     81:        pattern = argv[2];
                     82:     }
                     83: 
                     84:     /*
                     85:      * this initialize the library and check potential ABI mismatches
                     86:      * between the version it was compiled for and the actual shared
                     87:      * library used.
                     88:      */
                     89:     LIBXML_TEST_VERSION
                     90: 
                     91:     doc = extractFile(filename, (const xmlChar *) pattern);
                     92:     if (doc != NULL) {
                     93:         /*
                     94:         * ouptut the result.
                     95:         */
                     96:         xmlDocDump(stdout, doc);
                     97:        /*
                     98:         * don't forget to free up the doc
                     99:         */
                    100:        xmlFreeDoc(doc);
                    101:     }
                    102: 
                    103: 
                    104:     /*
                    105:      * Cleanup function for the XML library.
                    106:      */
                    107:     xmlCleanupParser();
                    108:     /*
                    109:      * this is to debug memory for regression tests
                    110:      */
                    111:     xmlMemoryDump();
                    112:     return(0);
                    113: }
                    114: 
                    115: #else
                    116: int main(void) {
                    117:     fprintf(stderr, "Reader, Pattern or output support not compiled in\n");
                    118:     exit(1);
                    119: }
                    120: #endif