From b0fdff2d6e3a1b269f3575c4c7c32ea249fabdfa Mon Sep 17 00:00:00 2001
From: Matt Nadareski <mnadareski@outlook.com>
Date: Sat, 26 Oct 2024 00:14:29 -0400
Subject: [PATCH] Find and fix equal size issue in streams

---
 SabreTools.Matching.Test/MatchUtilTests.cs  | 23 ++++++++++++++++++---
 SabreTools.Matching/Content/ContentMatch.cs |  4 ++++
 2 files changed, 24 insertions(+), 3 deletions(-)

diff --git a/SabreTools.Matching.Test/MatchUtilTests.cs b/SabreTools.Matching.Test/MatchUtilTests.cs
index e629784..b4a1d45 100644
--- a/SabreTools.Matching.Test/MatchUtilTests.cs
+++ b/SabreTools.Matching.Test/MatchUtilTests.cs
@@ -1,6 +1,5 @@
-using System;
 using System.Collections.Generic;
-using System.Linq;
+using System.IO;
 using SabreTools.Matching.Content;
 using Xunit;
 
@@ -9,7 +8,7 @@ namespace SabreTools.Matching.Test
     public class MatchUtilTests
     {
         [Fact]
-        public void ExactSizeMatch()
+        public void ExactSizeArrayMatch()
         {
             byte[] source = [0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07];
             byte?[] check = [0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07];
@@ -23,5 +22,23 @@ namespace SabreTools.Matching.Test
             string? actual = MatchUtil.GetFirstMatch("testfile", source, matchers);
             Assert.Equal(expected, actual);
         }
+
+        [Fact]
+        public void ExactSizeStreamMatch()
+        {
+            byte[] source = [0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07];
+            var stream = new MemoryStream(source);
+
+            byte?[] check = [0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07];
+            string expected = "match";
+
+            var matchers = new List<ContentMatchSet>
+            {
+                new(check, expected),
+            };
+            
+            string? actual = MatchUtil.GetFirstMatch("testfile", stream, matchers);
+            Assert.Equal(expected, actual);
+        }
     }
 }
\ No newline at end of file
diff --git a/SabreTools.Matching/Content/ContentMatch.cs b/SabreTools.Matching/Content/ContentMatch.cs
index 1adc2ee..9cc8ccf 100644
--- a/SabreTools.Matching/Content/ContentMatch.cs
+++ b/SabreTools.Matching/Content/ContentMatch.cs
@@ -134,6 +134,10 @@ namespace SabreTools.Matching.Content
             if (Needle.Length > stack.Length)
                 return -1;
 
+            // If the needle and stack are identically sized, short-circuit
+            if (Needle.Length == stack.Length)
+                return EqualAt(stack, 0) ? 0 : -1;
+
             // Set the default start and end values
             int start = Start;
             int end = End;