/** * section: Parsing * synopsis: Parse an XML document chunk by chunk to a tree and free it * purpose: Demonstrate the use of xmlCreatePushParserCtxt() and *          xmlParseChunk() to read an XML file progressively *          into a tree and and xmlFreeDoc() to free the resulting tree * usage: parse4 test3.xml * test: parse4 test3.xml * author: Daniel Veillard * copy: see Copyright for the status of this software. */ #include <stdio.h>#include <libxml/parser.h>#include <libxml/tree.h> #ifdef LIBXML_PUSH_ENABLEDstatic FILE *desc; /** * readPacket: * @mem: array to store the packet * @size: the packet size * * read at most @size bytes from the document and store it in @mem * * Returns the number of bytes read */static intreadPacket(char *mem, int size) {    int res;     res = fread(mem, 1, size, desc);    return(res);} /** * example4Func: * @filename: a filename or an URL * * Parse the resource and free the resulting tree */static voidexample4Func(const char *filename) {    xmlParserCtxtPtr ctxt;    char chars[4];    xmlDocPtr doc; /* the resulting document tree */    int res;     /*     * Read a few first byte to check the input used for the     * encoding detection at the parser level.     */    res = readPacket(chars, 4);    if (res <= 0) {        fprintf(stderr, "Failed to parse %s\n", filename);	return;    }     /*     * Create a progressive parsing context, the 2 first arguments     * are not used since we want to build a tree and not use a SAX     * parsing interface. We also pass the first bytes of the document     * to allow encoding detection when creating the parser but this     * is optional.     */    ctxt = xmlCreatePushParserCtxt(NULL, NULL,                                   chars, res, filename);    if (ctxt == NULL) {        fprintf(stderr, "Failed to create parser context !\n");	return;    }     /*     * loop on the input getting the document data, of course 4 bytes     * at a time is not realistic but allows to verify testing on small     * documents.     */    while ((res = readPacket(chars, 4)) > 0) {        xmlParseChunk(ctxt, chars, res, 0);    }     /*     * there is no more input, indicate the parsing is finished.     */    xmlParseChunk(ctxt, chars, 0, 1);     /*     * collect the document back and if it was wellformed     * and destroy the parser context.     */    doc = ctxt->myDoc;    res = ctxt->wellFormed;    xmlFreeParserCtxt(ctxt);     if (!res) {        fprintf(stderr, "Failed to parse %s\n", filename);    }     /*     * since we don't use the document, destroy it now.     */    xmlFreeDoc(doc);} int main(int argc, char **argv) {    if (argc != 2)        return(1);     /*     * 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     /*     * simulate a progressive parsing using the input file.     */    desc = fopen(argv[1], "rb");    if (desc != NULL) {	example4Func(argv[1]);	fclose(desc);    } else {        fprintf(stderr, "Failed to parse %s\n", argv[1]);    }     /*     * Cleanup function for the XML library.     */    xmlCleanupParser();    /*     * this is to debug memory for regression tests     */    xmlMemoryDump();    return(0);}#else /* ! LIBXML_PUSH_ENABLED */int main(int argc, char **argv) {    fprintf(stderr, "Library not compiled with push parser support\n");    return(1);}#endif