add (hacky and slow) reverse regex search

1 files changed, 18 insertions, 7 deletions

diff --git a/regex.c b/regex.c
index 710593f..6a362e4 100644
--- a/regex.c
+++ b/regex.c
@@ -846,18 +846,13 @@ void re_search_last_chunk(ReSearch *s) {
  * check s->flags to find if the match is done yet
  */
 
-int re_search_match(ReSearch *s, ReMatch *m) {
+int re_search_match_at_start(ReSearch *s, ReMatch *m) {
 	size_t i = s->buf_idx;
 	size_t n = s->buf_len;
 	while (i < n) {
-		if (s->re->first_byte && (~s->flags & RE_SEARCH_MID_MATCH)) {
-			const char *p = memchr(s->buf + i, s->re->first_byte, n - i);
-			if (!p) break;
-			i = p - s->buf;
-		}
 		isize r = re_search_try_match(s, i, n);
 		if (r < 0) {
-			i++;
+			return 0;
 		} else {
 			if (i == (usize)r) r++;
 			if (s->flags & RE_SEARCH_MID_MATCH) {
@@ -877,6 +872,22 @@ int re_search_match(ReSearch *s, ReMatch *m) {
 	return 0;
 }
 
+int re_search_match(ReSearch *s, ReMatch *m) {
+	u32 i = s->buf_idx;
+	u32 n = s->buf_len;
+	while (i < n) {
+		if (s->re->first_byte && (~s->flags & RE_SEARCH_MID_MATCH)) {
+			const char *p = memchr(s->buf + i, s->re->first_byte, n - i);
+			if (!p) break;
+			i = p - s->buf;
+		}
+		s->buf_idx = i++;
+		if (re_search_match_at_start(s, m)) return 1;
+	}
+	s->buf_idx = n;
+	return 0;
+}
+
 /* convenience wrappers */
 
 ReMatchList re_match_all(RegEx *re, Str s, Arena *a) {