Function lookup_prefix

mailmap.c:250–294

* Look for an entry in map that match string[0:len]; string[len] * does not have to be NUL (but it could be). */

 * does not have to be NUL (but it could be).
 */
static struct string_list_item *lookup_prefix(struct string_list *map,
					      const char *string, size_t len)
{
	bool exact_match;
	size_t i = string_list_find_insert_index(map, string, &exact_match);
	if (exact_match) {
		if (!string[len])
			return &map->items[i];
		/*
		 * that map entry matches exactly to the string, including
		 * the cruft at the end beyond "len".  That is not a match
		 * with string[0:len] that we are looking for.
		 */
	} else if (!string[len]) {
		/*
		 * asked with the whole string, and got nothing.  No
		 * matching entry can exist in the map.
		 */
		return NULL;
	}

	/*
	 * i is at the exact match to an overlong key, or location the
	 * overlong key would be inserted, which must come after the
	 * real location of the key if one exists.
	 */
	while (i-- && i < map->nr) {
		int cmp = strncasecmp(map->items[i].string, string, len);
		if (cmp < 0)
			/*
			 * "i" points at a key definitely below the prefix;
			 * the map does not have string[0:len] in it.
			 */
			break;
		else if (!cmp && !map->items[i].string[len])
			/* found it */
			return &map->items[i];
		/*
		 * otherwise, the string at "i" may be string[0:len]
		 * followed by a string that sorts later than string[len:];
		 * keep trying.
		 */
	}
	return NULL;
}

int map_user(struct string_list *map,
	     const char **email, size_t *emaillen,