add txt_range_equal()

1 files changed, 26 insertions, 0 deletions

diff --git a/txt.c b/txt.c
index 038140d..b4b4f54 100644
--- a/txt.c
+++ b/txt.c
@@ -323,6 +323,32 @@ u32 txt_read_chunk(TxtLoc *lo, TxtLoc hi, char *buf, u32 sz) {
 	return n;
 }
 
+Str txt_next_chunk(TxtLoc *l) {
+	TxtPiece *p = &l->t->ptbl.v[l->p];
+	Str s = { l->t->buf[p->buf].s + p->ofs + l->i, p->n - l->i };
+	if (l->p + 1 < l->t->ptbl.n) {
+		l->p++;
+		l->i = 0;
+	} else {
+		l->i = p->n;
+	}
+	return s;
+}
+
+int txt_range_equal(TxtLoc lo, TxtLoc hi, Str cmp) {
+	u32 i = 0;
+	while (txt_before(lo, hi)) {
+		Str s = txt_next_chunk(&lo);
+		u32 n = cmp.n - i;
+		if (s.n < n) n = s.n;
+		if (memcmp(s.s, cmp.s + i, n)) {
+			return 0;
+		}
+		i += s.n;
+	}
+	return 1;
+}
+
 /* navigation */
 
 int txt_valid_loc(TxtLoc l) {