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window(fill): bounds check the memcpy op

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Bounds check our window before performing any direct buffer access. This
affects clear and fill, and allows a window to technically be out of
bounds, but only the visual portion of the window will be filled.
This commit is contained in:
Tim Culverhouse 2024-05-11 06:38:08 -05:00
parent cce22e8850
commit f7f4606f1d
1 changed files with 3 additions and 2 deletions
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5
src/Window.zig
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@ -221,9 +221,10 @@ pub fn fill(self: Window, cell: Cell) void {
} else { } else {
// Non-contiguous. Iterate over rows an memset // Non-contiguous. Iterate over rows an memset
var row: usize = self.y_off; var row: usize = self.y_off;
while (row < (self.height + self.y_off)) : (row += 1) { const last_row = @min(self.height + self.y_off, self.screen.height - self.y_off);
while (row < last_row) : (row += 1) {
const start = self.x_off + (row * self.screen.width); const start = self.x_off + (row * self.screen.width);
const end = start + self.width; const end = @min(start + self.width, start + (self.screen.width - self.x_off));
@memset(self.screen.buf[start..end], cell); @memset(self.screen.buf[start..end], cell);
} }
} }