From b043e5eb8165b5c0ed52ec3d606a88a7e9cf961a Mon Sep 17 00:00:00 2001
From: Lehonti Ramos <john@doe>
Date: Mon, 7 Aug 2023 20:59:21 +0200
Subject: [PATCH] Made `BitMask` reject negative indexing

---
 Pinta.Core/Effects/BitMask.cs         |  9 +++++-
 tests/Pinta.Core.Tests/BitMaskTest.cs | 46 +++++++++++++++++++++++++++
 2 files changed, 54 insertions(+), 1 deletion(-)

diff --git a/Pinta.Core/Effects/BitMask.cs b/Pinta.Core/Effects/BitMask.cs
index ecf8830c9..d8b1209dd 100644
--- a/Pinta.Core/Effects/BitMask.cs
+++ b/Pinta.Core/Effects/BitMask.cs
@@ -69,5 +69,12 @@ public void Set (RectangleI rect, bool newValue)
 				Set (x, y, newValue);
 	}
 
-	private int GetIndex (int x, int y) => (y * Width) + x;
+	private int GetIndex (int x, int y)
+	{
+		if (x < 0)
+			throw new ArgumentOutOfRangeException (nameof(x));
+		if (y < 0)
+			throw new ArgumentOutOfRangeException (nameof (y));
+		return (y * Width) + x;
+	}
 }
diff --git a/tests/Pinta.Core.Tests/BitMaskTest.cs b/tests/Pinta.Core.Tests/BitMaskTest.cs
index 2dda90acd..58fa731d4 100644
--- a/tests/Pinta.Core.Tests/BitMaskTest.cs
+++ b/tests/Pinta.Core.Tests/BitMaskTest.cs
@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using Gtk;
 using NUnit.Framework;
 
 namespace Pinta.Core.Tests;
@@ -103,6 +104,44 @@ public void BitGetsSetXY (int maskWidth, int maskHeight, int bitToSetX, int bitT
 		}
 	}
 
+	[TestCaseSource (nameof (invalid_indexing))]
+	public void RejectsInvalidIndexing_PairIndexer (int width, int height, int x, int y)
+	{
+		var bitmask = new BitMask (width, height);
+		Assert.Throws<ArgumentOutOfRangeException> (() => _ = bitmask[x, y]);
+	}
+
+	[TestCaseSource (nameof (invalid_indexing))]
+	public void RejectsInvalidIndexing_PointIndexer (int width, int height, int x, int y)
+	{
+		var bitmask = new BitMask (width, height);
+		var point = new PointI (x, y);
+		Assert.Throws<ArgumentOutOfRangeException> (() => _ = bitmask[point]);
+	}
+
+	[TestCaseSource (nameof (invalid_indexing))]
+	public void RejectsInvalidIndexing_GetMethod (int width, int height, int x, int y)
+	{
+		var bitmask = new BitMask (width, height);
+		Assert.Throws<ArgumentOutOfRangeException> (() => _ = bitmask.Get (x, y));
+	}
+
+	[TestCaseSource (nameof (invalid_indexing))]
+	public void RejectsInvalidIndexing_Invert (int width, int height, int x, int y)
+	{
+		var bitmask = new BitMask (width, height);
+		Assert.Throws<ArgumentOutOfRangeException> (() => bitmask.Invert (x, y));
+	}
+
+	[TestCaseSource (nameof (invalid_indexing))]
+	public void RejectsInvalidIndexing_SetPair (int width, int height, int x, int y)
+	{
+		var bitmask1 = new BitMask (width, height);
+		var bitmask2 = new BitMask (width, height);
+		Assert.Throws<ArgumentOutOfRangeException> (() => bitmask1.Set (x, y, true));
+		Assert.Throws<ArgumentOutOfRangeException> (() => bitmask2.Set (x, y, false));
+	}
+
 	static readonly IReadOnlyList<TestCaseData> out_of_bounds_access_cases = new TestCaseData[]
 	{
 		new (0, 0),
@@ -122,4 +161,11 @@ public void BitGetsSetXY (int maskWidth, int maskHeight, int bitToSetX, int bitT
 		new (DEFAULT_SIZE, DEFAULT_OFFSET),
 		new (2, 1),
 	};
+
+	static readonly IReadOnlyList<TestCaseData> invalid_indexing = new TestCaseData[]
+	{
+		new (DEFAULT_WIDTH, DEFAULT_HEIGHT, -1, 0),
+		new (DEFAULT_WIDTH, DEFAULT_HEIGHT, 0, -1),
+		new (DEFAULT_WIDTH, DEFAULT_HEIGHT, -1, -1),
+	};
 }