Export dives in UDDF format

Implement exporting in UDDF format as was done in Gtk version. File menu
exports all the dives, right click on selection exports the selected
ones.

Signed-off-by: Miika Turkia <miika.turkia@gmail.com>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

save-xml.c

@@ -4,6 +4,7 @@
 #include <stdlib.h>
 #include <errno.h>
 #include <time.h>
+#include <unistd.h>
 
 #include "dive.h"
 #include "device.h"
@@ -601,3 +602,62 @@ void save_dives_logic(const char *filename, const bool select_only)
 	fprintf(f, "</dives>\n</divelog>\n");
 	fclose(f);
 }
+
+void export_dives_uddf(const char *filename, const bool selected)
+{
+	FILE *f;
+	size_t streamsize;
+	char *membuf;
+	xmlDoc *doc;
+	xsltStylesheetPtr xslt = NULL;
+	xmlDoc *transformed;
+
+	if (!filename)
+		return;
+
+	/* Save XML to file and convert it into a memory buffer */
+	save_dives_logic(filename, selected);
+	f = fopen(filename, "r");
+	fseek(f, 0, SEEK_END);
+	streamsize = ftell(f);
+	rewind(f);
+
+	membuf = malloc(streamsize + 1);
+	if (!membuf || !fread(membuf, streamsize, 1, f)) {
+		fprintf(stderr, "Failed to read memory buffer\n");
+		return;
+	}
+	membuf[streamsize] = 0;
+	fclose(f);
+	unlink(filename);
+
+	/*
+	 * Parse the memory buffer into XML document and
+	 * transform it to UDDF format, finally dumping
+	 * the XML into a character buffer.
+	 */
+	doc = xmlReadMemory(membuf, strlen(membuf), "divelog", NULL, 0);
+	if (!doc) {
+		fprintf(stderr, "Failed to read XML memory\n");
+		return;
+	}
+	free((void *)membuf);
+
+	/* Convert to UDDF format */
+	xslt = get_stylesheet("uddf-export.xslt");
+
+	if (!xslt) {
+		fprintf(stderr, "Failed to open UDDF conversion stylesheet\n");
+		return;
+	}
+	transformed = xsltApplyStylesheet(xslt, doc, NULL);
+	xsltFreeStylesheet(xslt);
+	xmlFreeDoc(doc);
+
+	/* Write the transformed XML to file */
+	f = fopen(filename, "w");
+	xmlDocFormatDump(f, transformed, 1);
+	xmlFreeDoc(transformed);
+
+	fclose(f);
+}