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