[libxml2]Add libxml2 library

libxml2/example/parse4.c

@@ -0,0 +1,135 @@
+/**
+ * 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]);
+    }
+
+    return(0);
+}
+#else /* ! LIBXML_PUSH_ENABLED */
+int main(void) {
+    fprintf(stderr, "Library not compiled with push parser support\n");
+    return(0);
+}
+#endif