deduplicate reinserted buffer text somewhat

1 files changed, 41 insertions, 17 deletions

diff --git a/txt.c b/txt.c
index 9d5be97..7092964 100644
--- a/txt.c
+++ b/txt.c
@@ -56,6 +56,15 @@ static void txt_buf_append(Txt *b, TxtBufIdx bi, const char *s, u32 n) {
 	buf->n += n;
 }
 
+static isize txt_buf_dedup(Txt *b, TxtBufIdx bi, const char *s, u32 n) {
+	TxtBuf *buf = &b->buf[bi];
+	if (buf->n >= n && !memcmp(buf->s + (buf->n - n), s, n)) {
+		return buf->n - n;
+	} else {
+		return -1;
+	}
+}
+
 TxtLoc txt_add_piece(Txt *b, TxtLoc l) {
 	if (l.p > 0 && !l.i) {
 		l.p--;
@@ -79,23 +88,6 @@ insert:
 	return l;
 }
 
-TxtLoc txt_insert(TxtLoc l, const char *s, u32 n) {
-	l = txt_add_piece(l.t, l);
-	TxtPiece *p = &l.t->ptbl.v[l.p];
-	txt_buf_append(l.t, p->buf, s, n);
-	p->n += n;
-	l.t->len += n;
-	l.i = p->n;
-	return l;
-}
-
-TxtLoc txt_insert_c(TxtLoc l, u32 ch) {
-	char buf[6];
-	u32 n = utf8_encode_len(&ch, 1);
-	utf8_encode(buf, &ch, 1);
-	return txt_insert(l, buf, n);
-}
-
 static int txt_are_pieces_adjacent(Txt *t, u32 a, u32 b) {
 	TxtPiece *pa = &t->ptbl.v[a];
 	TxtPiece *pb = &t->ptbl.v[b];
@@ -136,6 +128,30 @@ static TxtLoc txt_join_or_kill(TxtLoc l) {
 	return l;
 }
 
+TxtLoc txt_insert(TxtLoc l, const char *s, u32 n) {
+	l = txt_add_piece(l.t, l);
+	TxtPiece *p = &l.t->ptbl.v[l.p];
+	isize ext = txt_buf_dedup(l.t, p->buf, s, n);
+	if (p->n > 0 || ext == -1) {
+		txt_buf_append(l.t, p->buf, s, n);
+	} else {
+		p->ofs = ext;
+	}
+	p->n += n;
+	l.t->len += n;
+	l.i = p->n;
+	l = txt_join_or_kill(l);
+	l.i = l.t->ptbl.v[l.p].n;
+	return l;
+}
+
+TxtLoc txt_insert_c(TxtLoc l, u32 ch) {
+	char buf[6];
+	u32 n = utf8_encode_len(&ch, 1);
+	utf8_encode(buf, &ch, 1);
+	return txt_insert(l, buf, n);
+}
+
 TxtLoc txt_delete(TxtLoc l, u32 n) {
 	u32 pi = txt_split_piece(l.t, l.p, l.i);
 	if (pi > 0) pi--;
@@ -160,6 +176,14 @@ TxtLoc txt_delete(TxtLoc l, u32 n) {
 	return txt_join_or_kill(l);
 }
 
+TxtLoc txt_delete_range(TxtLoc lo, TxtLoc hi) {
+	/* TODO: figure out nr. of chars, then delete all at once */
+	while (txt_before(lo, hi)) {
+		hi = txt_delete(hi, 1);
+	}
+	return lo;
+}
+
 TxtLoc txt_delete_c(TxtLoc l) {
 	while (!at_start(l) && (txt_byte(bprev(l)) & 0xc0) == 0x80) 
 		l = txt_delete(l, 1);