+ const char *pgm = external_diff();
+ if (!pgm &&
+ DIFF_FILE_VALID(one) && DIFF_FILE_VALID(two) &&
+ (S_IFMT & one->mode) != (S_IFMT & two->mode)) {
+ /* a filepair that changes between file and symlink
+ * needs to be split into deletion and creation.
+ */
+ struct diff_filespec *null = alloc_filespec(two->path);
+ run_external_diff(NULL, name, other, one, null, xfrm_msg);
+ free(null);
+ null = alloc_filespec(one->path);
+ run_external_diff(NULL, name, other, null, two, xfrm_msg);
+ free(null);
+ }
+ else
+ run_external_diff(pgm, name, other, one, two, xfrm_msg);
+}
+
+void diff_setup(int flags)
+{
+ if (flags & DIFF_SETUP_REVERSE)
+ reverse_diff = 1;
+ if (flags & DIFF_SETUP_USE_CACHE) {
+ if (!active_cache)
+ /* read-cache does not die even when it fails
+ * so it is safe for us to do this here. Also
+ * it does not smudge active_cache or active_nr
+ * when it fails, so we do not have to worry about
+ * cleaning it up oufselves either.
+ */
+ read_cache();
+ }
+ if (flags & DIFF_SETUP_USE_SIZE_CACHE)
+ use_size_cache = 1;
+
+}
+
+static int parse_num(const char **cp_p)
+{
+ int num, scale, ch, cnt;
+ const char *cp = *cp_p;
+
+ cnt = num = 0;
+ scale = 1;
+ while ('0' <= (ch = *cp) && ch <= '9') {
+ if (cnt++ < 5) {
+ /* We simply ignore more than 5 digits precision. */
+ scale *= 10;
+ num = num * 10 + ch - '0';
+ }
+ *cp++;
+ }
+ *cp_p = cp;
+
+ /* user says num divided by scale and we say internally that
+ * is MAX_SCORE * num / scale.
+ */
+ return (MAX_SCORE * num / scale);
+}
+
+int diff_scoreopt_parse(const char *opt)
+{
+ int opt1, opt2, cmd;
+
+ if (*opt++ != '-')
+ return -1;
+ cmd = *opt++;
+ if (cmd != 'M' && cmd != 'C' && cmd != 'B')
+ return -1; /* that is not a -M, -C nor -B option */
+
+ opt1 = parse_num(&opt);
+ if (cmd != 'B')
+ opt2 = 0;
+ else {
+ if (*opt == 0)
+ opt2 = 0;
+ else if (*opt != '/')
+ return -1; /* we expect -B80/99 or -B80 */
+ else {
+ opt++;
+ opt2 = parse_num(&opt);
+ }
+ }
+ if (*opt != 0)
+ return -1;
+ return opt1 | (opt2 << 16);