for (dst = buf; size; size--) {
const char *cp;
+ /* Fetch next source character, move the pointer on */
char ch = *src++;
+ /* Copy the current character to the destination */
*dst++ = ch;
+ /* If the current character is "$" or there are less than three
+ * remaining bytes or the two bytes following this one are not
+ * "Id", then simply read the next character */
if ((ch != '$') || (size < 3) || memcmp("Id", src, 2))
continue;
+ /*
+ * Here when
+ * - There are more than 2 bytes remaining
+ * - The current three bytes are "$Id"
+ * with
+ * - ch == "$"
+ * - src[0] == "I"
+ */
+ /*
+ * It's possible that an expanded Id has crept its way into the
+ * repository, we cope with that by stripping the expansion out
+ */
if (src[2] == ':') {
+ /* Expanded keywords have "$Id:" at the front */
+
/* discard up to but not including the closing $ */
unsigned long rem = size - 3;
+ /* Point at first byte after the ":" */
cp = src + 3;
+ /*
+ * Throw away characters until either
+ * - we reach a "$"
+ * - we run out of bytes (rem == 0)
+ */
do {
- ch = *cp++;
+ ch = *cp;
if (ch == '$')
break;
+ cp++;
rem--;
} while (rem);
+ /* If the above finished because it ran out of characters, then
+ * this is an incomplete keyword, so don't run the expansion */
if (!rem)
continue;
- size -= (cp - src);
} else if (src[2] == '$')
cp = src + 2;
else
+ /* Anything other than "$Id:XXX$" or $Id$ and we skip the
+ * expansion */
continue;
+ /* cp is now pointing at the last $ of the keyword */
+
memcpy(dst, "Id: ", 4);
dst += 4;
memcpy(dst, sha1_to_hex(sha1), 40);
dst += 40;
*dst++ = ' ';
+
+ /* Adjust for the characters we've discarded */
size -= (cp - src);
src = cp;
+
+ /* Copy the final "$" */
*dst++ = *src++;
size--;
}