- this_version = version_number (file, dp->d_name, file_name_length);
- if (this_version > highest_version)
- highest_version = this_version;
+ p = dp->d_name + baselen + 2;
+
+ /* Check whether this file has a version number and if so,
+ whether it is larger. Use string operations rather than
+ integer arithmetic, to avoid problems with integer overflow. */
+
+ if (! ('1' <= *p && *p <= '9'))
+ continue;
+ all_9s = (*p == '9');
+ for (versionlen = 1; ISDIGIT (p[versionlen]); versionlen++)
+ all_9s &= (p[versionlen] == '9');
+
+ if (! (p[versionlen] == '~' && !p[versionlen + 1]
+ && (versionlenmax < versionlen
+ || (versionlenmax == versionlen
+ && memcmp (buf + filelen + 2, p, versionlen) <= 0))))
+ continue;
+
+ /* This directory has the largest version number seen so far.
+ Append this highest numbered extension to the file name,
+ prepending '0' to the number if it is all 9s. */
+
+ versionlenmax = all_9s + versionlen;
+ result = (all_9s ? BACKUP_IS_LONGER : BACKUP_IS_SAME_LENGTH);
+ new_buflen = filelen + 2 + versionlenmax + 1;
+ if (buffer_size <= new_buflen)
+ {
+ buf = xnrealloc (buf, 2, new_buflen);
+ buffer_size = new_buflen * 2;
+ }
+ q = buf + filelen;
+ *q++ = '.';
+ *q++ = '~';
+ *q = '0';
+ q += all_9s;
+ memcpy (q, p, versionlen + 2);
+
+ /* Add 1 to the version number. */
+
+ q += versionlen;
+ while (*--q == '9')
+ *q = '0';
+ ++*q;