doc: Move doc/examples to example

example/reader3.c

@@ -0,0 +1,111 @@
+/**
+ * section: xmlReader
+ * synopsis: Show how to extract subdocuments with xmlReader
+ * purpose: Demonstrate the use of xmlTextReaderPreservePattern() 
+ *          to parse an XML file with the xmlReader while collecting
+ *          only some subparts of the document.
+ *          (Note that the XMLReader functions require libxml2 version later
+ *          than 2.6.)
+ * usage: reader3
+ * test: reader3 > reader3.tmp && diff reader3.tmp $(srcdir)/reader3.res
+ * author: Daniel Veillard
+ * copy: see Copyright for the status of this software.
+ */
+
+#include <stdio.h>
+#include <libxml/xmlreader.h>
+
+#if defined(LIBXML_READER_ENABLED) && defined(LIBXML_PATTERN_ENABLED) && defined(LIBXML_OUTPUT_ENABLED)
+
+
+/**
+ * streamFile:
+ * @filename: the file name to parse
+ *
+ * Parse and print information about an XML file.
+ *
+ * Returns the resulting doc with just the elements preserved.
+ */
+static xmlDocPtr
+extractFile(const char *filename, const xmlChar *pattern) {
+    xmlDocPtr doc;
+    xmlTextReaderPtr reader;
+    int ret;
+
+    /*
+     * build an xmlReader for that file
+     */
+    reader = xmlReaderForFile(filename, NULL, 0);
+    if (reader != NULL) {
+        /*
+	 * add the pattern to preserve
+	 */
+        if (xmlTextReaderPreservePattern(reader, pattern, NULL) < 0) {
+            fprintf(stderr, "%s : failed add preserve pattern %s\n",
+	            filename, (const char *) pattern);
+	}
+	/*
+	 * Parse and traverse the tree, collecting the nodes in the process
+	 */
+        ret = xmlTextReaderRead(reader);
+        while (ret == 1) {
+            ret = xmlTextReaderRead(reader);
+        }
+        if (ret != 0) {
+            fprintf(stderr, "%s : failed to parse\n", filename);
+	    xmlFreeTextReader(reader);
+	    return(NULL);
+        }
+	/*
+	 * get the resulting nodes
+	 */
+	doc = xmlTextReaderCurrentDoc(reader);
+	/*
+	 * Free up the reader
+	 */
+        xmlFreeTextReader(reader);
+    } else {
+        fprintf(stderr, "Unable to open %s\n", filename);
+	return(NULL);
+    }
+    return(doc);
+}
+
+int main(int argc, char **argv) {
+    const char *filename = "test3.xml";
+    const char *pattern = "preserved";
+    xmlDocPtr doc;
+
+    if (argc == 3) {
+        filename = argv[1];
+	pattern = argv[2];
+    }
+
+    /*
+     * 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
+
+    doc = extractFile(filename, (const xmlChar *) pattern);
+    if (doc != NULL) {
+        /*
+	 * output the result.
+	 */
+        xmlDocDump(stdout, doc);
+	/*
+	 * don't forget to free up the doc
+	 */
+	xmlFreeDoc(doc);
+    }
+
+    return(0);
+}
+
+#else
+int main(void) {
+    fprintf(stderr, "Reader, Pattern or output support not compiled in\n");
+    return(0);
+}
+#endif