From f98b551ba26de9a0e1a4d555dcf0de780b59800b Mon Sep 17 00:00:00 2001
From: Sasha Koshka <sashakoshka@tebibyte.media>
Date: Sun, 6 Nov 2022 15:25:55 -0500
Subject: [PATCH] Added bounds checking to buffer

---
 buffer.go | 27 ++++++++++++++++++++++++---
 1 file changed, 24 insertions(+), 3 deletions(-)

diff --git a/buffer.go b/buffer.go
index 9bf6dec..abc9593 100644
--- a/buffer.go
+++ b/buffer.go
@@ -49,6 +49,15 @@ type Buffer struct {
 	}
 }
 
+func (buffer *Buffer) isOutOfBounds (x, y int) (outOfBounds bool) {
+	outOfBounds =
+		x < 0 ||
+		y < 0 ||
+		x >= buffer.width ||
+		y >= buffer.height
+	return
+}
+
 func (buffer *Buffer) Size () (width, height int) {
 	width  = buffer.width
 	height = buffer.height
@@ -62,19 +71,23 @@ func (buffer *Buffer) SetSize (width, height int) {
 }
 
 func (buffer *Buffer) Cell (x, y int) (cell Cell) {
+	if buffer.isOutOfBounds(x, y) { return }
 	cell = buffer.content[x + y * buffer.width]
 	return
 }
 
 func (buffer *Buffer) SetColor (x, y int, color Color) {
+	if buffer.isOutOfBounds(x, y) { return }
 	buffer.content[x + y * buffer.width].color = color
 }
 
 func (buffer *Buffer) SetStyle (x, y int, style Style) {
+	if buffer.isOutOfBounds(x, y) { return }
 	buffer.content[x + y * buffer.width].style = style
 }
 
 func (buffer *Buffer) SetRune (x, y int, content rune) {
+	if buffer.isOutOfBounds(x, y) { return }
 	buffer.content[x + y * buffer.width].content = content
 }
 
@@ -110,18 +123,24 @@ func (buffer *DamageBuffer) SetSize (width, height int) {
 }
 
 func (buffer *DamageBuffer) SetColor (x, y int, color Color) {
+	if buffer.isOutOfBounds(x, y) { return }
+	index := x + y * buffer.width
+	buffer.clean[index] = buffer.content[index].color == color
 	buffer.Buffer.SetColor(x, y, color)
-	buffer.clean[x + y * buffer.width] = false
 }
 
 func (buffer *DamageBuffer) SetStyle (x, y int, style Style) {
+	if buffer.isOutOfBounds(x, y) { return }
+	index := x + y * buffer.width
+	buffer.clean[index] = buffer.content[index].style == style
 	buffer.Buffer.SetStyle(x, y, style)
-	buffer.clean[x + y * buffer.width] = false
 }
 
 func (buffer *DamageBuffer) SetRune (x, y int, content rune) {
+	if buffer.isOutOfBounds(x, y) { return }
+	index := x + y * buffer.width
+	buffer.clean[index] = buffer.content[index].content == content
 	buffer.Buffer.SetRune(x, y, content)
-	buffer.clean[x + y * buffer.width] = false
 }
 
 func (buffer *DamageBuffer) Write (bytes []byte) (bytesWritten int, err error) {
@@ -141,10 +160,12 @@ func (buffer *DamageBuffer) Write (bytes []byte) (bytesWritten int, err error) {
 }
 
 func (buffer *DamageBuffer) Clean (x, y int) (clean bool) {
+	if buffer.isOutOfBounds(x, y) { return }
 	clean = buffer.clean[x + y * buffer.width]
 	return
 }
 
 func (buffer *DamageBuffer) MarkClean (x, y int) {
+	if buffer.isOutOfBounds(x, y) { return }
 	buffer.clean[x + y * buffer.width] = true
 }