vtgl

Commit: 1eb870dd331ab9235aa1f1e79b8d947647a46b09
Parent: 74a07eb867da5ff89d82991b946540bc99610802
Author: Randy Palamar
Date:   Thu, 31 Oct 2024 07:42:53 -0600

make sure backwards tab also works across boundaries

Diffstat:
M
terminal.c
 | 
22
+++++++++++-----------
M
test.c
 | 
8
++++++++

2 files changed, 19 insertions(+), 11 deletions(-)
diff --git a/terminal.c b/terminal.c
@@ -341,18 +341,18 @@ next_tab_position(Term *t, b32 backwards)
 	u32 bit  = col % ARRAY_COUNT(t->tabs);
 	u32 mask = safe_left_shift(1, bit - backwards) - 1;
 
-	u32 result = 32 * idx, zeroes;
-	if (backwards) zeroes = 32 - _lzcnt_u32(t->tabs[idx++] & mask);
-	else           zeroes = _tzcnt_u32(t->tabs[idx++] & ~mask);
-	result += zeroes;
-
-	/* NOTE we may need to advance across idx boundaries */
-	while (idx < ARRAY_COUNT(t->tabs) && zeroes == 32) {
-		if (backwards) zeroes = 32 - _lzcnt_u32(t->tabs[idx++]);
-		else           zeroes = _tzcnt_u32(t->tabs[idx++]);
-		result += zeroes;
+	u32 result = 32 * idx;
+	if (backwards) {
+		u32 zeroes = _lzcnt_u32(t->tabs[idx--] & mask);
+		while (idx < ARRAY_COUNT(t->tabs) && zeroes == 32)
+			zeroes = _lzcnt_u32(t->tabs[idx--]);
+		result = 32 * (idx + 1) + 32 - zeroes;
+	} else {
+		u32 zeroes = _tzcnt_u32(t->tabs[idx++] & ~mask);
+		while (idx < ARRAY_COUNT(t->tabs) && zeroes == 32)
+			zeroes = _tzcnt_u32(t->tabs[idx++]);
+		result = 32 * (idx - 1) + zeroes + 1;
 	}
-	result += !backwards;
 	ASSERT(result < t->size.w);
 
 	return result;
diff --git a/test.c b/test.c
@@ -328,6 +328,14 @@ static TEST_FN(cursor_tabs_across_boundary)
 	handle_input(term, arena, raw);
 	result.status &= term->cursor.pos.x == 33;
 
+	/* NOTE: ensure backwards tab works */
+	launder_static_string(term, CSI(1;34H));
+	launder_static_string(term, ESC(0g));
+	launder_static_string(term, CSI(1;66H));
+	raw = launder_static_string(term, CSI(1Z));
+	handle_input(term, arena, raw);
+	result.status &= term->cursor.pos.x == 33;
+
 	return result;
 }