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+/**
+ * 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 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_ENABLED
+static 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 int
+readPacket(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 void
+example4Func(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