#include <stdlib.h>
#include <string.h>
#include <limits.h>
-#include "delta.h"
#include "count-delta.h"
static unsigned long get_hdr_size(const unsigned char **datap)
/*
* NOTE. We do not _interpret_ delta fully. As an approximation, we
* just count the number of bytes that are copied from the source, and
- * the number of literal data bytes that are inserted. Number of
- * bytes that are _not_ copied from the source is deletion, and number
- * of inserted literal bytes are addition, so sum of them is what we
- * return. xdelta can express an edit that copies data inside of the
- * destination which originally came from the source. We do not count
- * that in the following routine, so we are undercounting the source
- * material that remains in the final output that way.
+ * the number of literal data bytes that are inserted.
+ *
+ * Number of bytes that are _not_ copied from the source is deletion,
+ * and number of inserted literal bytes are addition, so sum of them
+ * is the extent of damage. xdelta can express an edit that copies
+ * data inside of the destination which originally came from the
+ * source. We do not count that in the following routine, so we are
+ * undercounting the source material that remains in the final output
+ * that way.
*/
-unsigned long count_delta(void *delta_buf, unsigned long delta_size)
+int count_delta(void *delta_buf, unsigned long delta_size,
+ unsigned long *src_copied, unsigned long *literal_added)
{
unsigned long copied_from_source, added_literal;
const unsigned char *data, *top;
/* the smallest delta size possible is 6 bytes */
if (delta_size < 6)
- return UINT_MAX;
+ return -1;
data = delta_buf;
top = delta_buf + delta_size;
/* sanity check */
if (data != top || out != dst_size)
- return UINT_MAX;
+ return -1;
/* delete size is what was _not_ copied from source.
* edit size is that and literal additions.
*/
- return (src_size - copied_from_source) + added_literal;
+ *src_copied = copied_from_source;
+ *literal_added = added_literal;
+ return 0;
}