remove most explicit Txt* params, fix some utf-8 problems

1 files changed, 144 insertions, 82 deletions

diff --git a/txt.c b/txt.c
index 38f34c4..b2dc2d8 100644
--- a/txt.c
+++ b/txt.c
@@ -56,7 +56,7 @@ static void txt_buf_append(Txt *b, TxtBufIdx bi, const char *s, u32 n) {
 	buf->n += n;
 }
 
-u32 txt_add_piece(Txt *b, TxtLoc l) {
+TxtLoc txt_add_piece(Txt *b, TxtLoc l) {
 	if (l.p > 0 && !l.i) {
 		l.p--;
 		l.i = b->ptbl.v[l.p].n;
@@ -76,24 +76,24 @@ insert:
 			txt_insert_piece(b, l.p, TXT_ADD, b->buf[TXT_ADD].n, 0);
 		}
 	}
-	return l.p;
+	return l;
 }
 
-u32 txt_insert(Txt *b, u32 cur, const char *s, u32 n) {
-	TxtLoc l = txt_at(b, cur);
-	l.p = txt_add_piece(b, l);
-	TxtPiece *p = &b->ptbl.v[l.p];
-	txt_buf_append(b, p->buf, s, n);
+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;
-	b->len += n;
-	return cur + n;
+	l.t->len += n;
+	l.i = p->n;
+	return l;
 }
 
-u32 txt_insert_c(Txt *b, u32 cur, u32 ch) {
+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(b, cur, buf, n);
+	return txt_insert(l, buf, n);
 }
 
 static int txt_are_pieces_adjacent(Txt *t, u32 a, u32 b) {
@@ -102,46 +102,46 @@ static int txt_are_pieces_adjacent(Txt *t, u32 a, u32 b) {
 	return pa->buf == pb->buf && pa->ofs + pa->n == pb->ofs;
 }
 
-static void txt_join_or_kill(Txt *b, u32 pi) {
-	if (b->ptbl.v[pi].n == 0 && !(pi == 0 && b->ptbl.n == 1)) {
-		txt_remove_piece(b, pi);
+static TxtLoc txt_join_or_kill(TxtLoc l) {
+	Txt *b = l.t;
+	if (l.t->ptbl.v[l.p].n == 0 && !(l.p == 0 && b->ptbl.n == 1)) {
+		txt_remove_piece(b, l.p);
 	}
-	if (pi + 1 < b->ptbl.n && txt_are_pieces_adjacent(b, pi, pi + 1)) {
-		b->ptbl.v[pi].n += b->ptbl.v[pi+1].n;
-		txt_remove_piece(b, pi + 1);
+	if (l.p + 1 < b->ptbl.n && txt_are_pieces_adjacent(b, l.p, l.p + 1)) {
+		b->ptbl.v[l.p].n += b->ptbl.v[l.p+1].n;
+		txt_remove_piece(b, l.p + 1);
 	}
+	return l;
 }
 
-u32 txt_delete(Txt *b, u32 cur, u32 n) {
-	TxtLoc l = txt_at(b, cur);
-	u32 pi = txt_split_piece(b, l.p, l.i);
+TxtLoc txt_delete(TxtLoc l, u32 n) {
+	u32 pi = txt_split_piece(l.t, l.p, l.i);
 	if (pi > 0) pi--;
-	if (n > cur) n = cur;
-	cur -= n;
-	b->len -= n;
+	l.p = pi;
+	l.i = l.t->ptbl.v[l.p].n;
 	for (;;) {
-		TxtPiece *p = &b->ptbl.v[pi];
-		if (n >= p->n) {
-			n -= p->n;
-			p->n = 0;
-			if (pi > 0 || b->ptbl.n > 1) txt_remove_piece(b, pi);
-		} else {
-			p->n -= n;
-			n = 0;
+		ASSERT(l.i == l.t->ptbl.v[l.p].n);
+		if (l.i >= n) {
+			l.i -= n;
+			l.t->ptbl.v[l.p].n -= n;
 			break;
+		} else {
+			l.t->ptbl.v[l.p].n -= l.i;
+			n -= l.i;
+			l.i = 0;
+			if (l.p == 0) break;
+			l.p = l.p - 1;
+			l.i = l.t->ptbl.v[l.p].n;
 		}
-		if (pi == 0) break;
-		pi--;
 	}
-	txt_join_or_kill(b, pi);
-	return cur;
+	return txt_join_or_kill(l);
 }
 
-u32 txt_delete_c(Txt *b, u32 cur) {
-	while (cur > 0 && (txt_byte(b, txt_at(b, cur-1)) & 0xc0) == 0x80) 
-		cur = txt_delete(b, cur, 1);
-	cur = txt_delete(b, cur, 1);
-	return cur;
+TxtLoc txt_delete_c(TxtLoc l) {
+	while (!at_start(l) && (txt_byte(l) & 0xc0) == 0x80) 
+		l = txt_delete(l, 1);
+	l = txt_delete(l, 1);
+	return l;
 }
 
 int txt_load(Txt *b, const char *path) {
@@ -195,44 +195,37 @@ void txt_free(Txt *t) {
 	free(t->ptbl.v);
 }
 
-/* reading individual chars */
+/* navigation */
 
-u8 txt_byte(Txt *t, TxtLoc l) {
-	TxtPiece *p = &t->ptbl.v[l.p];
-	TxtBuf *b = &t->buf[p->buf];
-	if (l.i >= p->n) return 0;
-	return b->s[p->ofs + l.i];
-}
-
-u32 txt_chr(Txt *t, TxtLoc l) {
-	TxtPiece *p = &t->ptbl.v[l.p];
-	TxtBuf *b = &t->buf[p->buf];
-	return utf8_decode_at(b->s, p->ofs + l.i, p->ofs + p->n);
-}
-
-/* cursor manipulation */
-
-TxtLoc txt_at(Txt *b, u32 cur) {
+TxtLoc txt_at(Txt *b, u32 ofs) {
 	for (u32 i = 0; i < b->ptbl.n; i++) {
-		if (cur < b->ptbl.v[i].n) {
-			return (TxtLoc) { b, i, cur };
+		if (ofs < b->ptbl.v[i].n) {
+			return (TxtLoc) { b, i, ofs };
 		}
-		cur -= b->ptbl.v[i].n;
+		ofs -= b->ptbl.v[i].n;
 	}
 	return (TxtLoc) { b, b->ptbl.n - 1, b->ptbl.v[b->ptbl.n - 1].n };
 }
 
-u32 txt_ofs(Txt *b, TxtLoc l) {
+u32 txt_ofs(TxtLoc l) {
 	u32 r = 0;
 	for (u32 i = 0; i < l.p; i++) {
-		r += b->ptbl.v[i].n;
+		r += l.t->ptbl.v[i].n;
 	}
 	return r + l.i;
 }
 
-TxtLoc txt_next(Txt *b, TxtLoc l) {
-	TxtPiece *p = &b->ptbl.v[l.p];
-	if (l.p + 1 < b->ptbl.n) {
+int txt_before(TxtLoc a, TxtLoc b) {
+	return a.p < b.p || (a.p == b.p && a.i < b.i);
+}
+
+int txt_after(TxtLoc a, TxtLoc b) {
+	return a.p > b.p || (a.p == b.p && a.i > b.i);
+}
+
+TxtLoc bnext(TxtLoc l) {
+	TxtPiece *p = &l.t->ptbl.v[l.p];
+	if (l.p + 1 < l.t->ptbl.n) {
 		if (l.i + 1 < p->n) l.i++;
 		else l.p++, l.i = 0;
 	} else {
@@ -242,37 +235,106 @@ TxtLoc txt_next(Txt *b, TxtLoc l) {
 	return l;
 }
 
-TxtLoc txt_prev(Txt *b, TxtLoc l) {
+TxtLoc bprev(TxtLoc l) {
 	if (l.i > 0) {
-		return (TxtLoc) { b, l.p, l.i - 1 };
-	} else if (l.p > 0) {
-		return (TxtLoc) { b, l.p - 1, b->ptbl.v[l.p - 1].n - 1 };
+		return (TxtLoc) { l.t, l.p, l.i - 1 };
+	} else if (l.p > 0 && l.t->ptbl.v[l.p - 1].n > 0) {
+		return (TxtLoc) { l.t, l.p - 1, l.t->ptbl.v[l.p - 1].n - 1 };
 	} else {
-		return (TxtLoc) { b, 0, 0 };
+		return (TxtLoc) { l.t, 0, 0 };
 	}
 }
 
-int txt_at_start(Txt *b, TxtLoc l) {
-	(void)b;
+TxtLoc cnext(TxtLoc l) {
+	l = bnext(l);
+	while ((txt_byte(l) & 0xc0) == 0x80) l = bnext(l);
+	return l;
+}
+
+TxtLoc cprev(TxtLoc l) {
+	l = bprev(l);
+	while ((txt_byte(l) & 0xc0) == 0x80) l = bprev(l);
+	return l;
+}
+
+int at_start(TxtLoc l) {
 	return l.p == 0 && l.i == 0;
 }
 
-int txt_at_end(Txt *b, TxtLoc l) {
-	return l.p + 1 == b->ptbl.n && l.i == b->ptbl.v[l.p].n;
+int at_end(TxtLoc l) {
+	return l.p + 1 == l.t->ptbl.n && l.i == l.t->ptbl.v[l.p].n;
 }
 
-int txt_before(TxtLoc a, TxtLoc b) {
-	return a.p < b.p || (a.p == b.p && a.i < b.i);
+TxtLoc next_newline(TxtLoc l) {
+	do l = cnext(l);
+	while (!at_end(l) && txt_byte(l) != '\n');
+	return l;
 }
 
-int txt_after(TxtLoc a, TxtLoc b) {
-	return a.p > b.p || (a.p == b.p && a.i > b.i);
+TxtLoc prev_newline(TxtLoc l) {
+	do l = cprev(l);
+	while (!at_start(l) && txt_byte(l) != '\n');
+	return l;
+}
+
+TxtLoc start_of_line(TxtLoc l) {
+	l = prev_newline(l);
+	if (!at_start(l) && txt_byte(l) == '\n') l = cnext(l);
+	return l;
+}
+
+TxtLoc end_of_line(TxtLoc l) {
+	TxtLoc start = start_of_line(l);
+	return txt_byte(start) == '\n' ? start : next_newline(start);
+}
+
+u32 get_col(TxtLoc l) {
+	u32 n = 0;
+	for (TxtLoc tmp = start_of_line(l); txt_before(tmp, l); txt_chr_next(&tmp)) n++;
+	return n;
+}
+
+TxtLoc at_col(TxtLoc l, u32 col) {
+	l = start_of_line(l);
+	while (col--) {
+		if (txt_chr_next(&l) == '\n') {
+			l = bprev(l);
+			break;
+		}
+	}
+	return l;
+}
+
+TxtLoc prev_line(TxtLoc l) {
+	TxtLoc start = start_of_line(l);
+	return at_col(cprev(start), get_col(l));
+}
+
+TxtLoc next_line(TxtLoc l) {
+	TxtLoc end = end_of_line(l);
+	if (at_end(end)) return end;
+	return at_col(cnext(end), get_col(l));
+}
+
+/* reading chars */
+
+u32 txt_chr(TxtLoc l) {
+	TxtPiece *p = &l.t->ptbl.v[l.p];
+	TxtBuf *b = &l.t->buf[p->buf];
+	return utf8_decode_at(b->s, p->ofs + l.i, p->ofs + p->n);
+}
+
+u8 txt_byte(TxtLoc l) {
+	TxtPiece *p = &l.t->ptbl.v[l.p];
+	TxtBuf *b = &l.t->buf[p->buf];
+	if (l.i >= p->n) return 0;
+	return b->s[p->ofs + l.i];
 }
 
-u32 txt_chr_next(Txt *t, TxtLoc *l) {
-	if (txt_at_end(t, *l)) return 0;
-	u32 c = txt_chr(t, *l);
+u32 txt_chr_next(TxtLoc *l) {
+	if (at_end(*l)) return 0;
+	u32 c = txt_chr(*l);
 	u32 n = UTF8_CP_LEN(c);
-	for (u32 i = 0; i < n; i++) *l = txt_next(t, *l);
+	for (u32 i = 0; i < n; i++) *l = bnext(*l);
 	return c;
 }