From b1d95652eaa10959bb7f2f0dc0b2c3a4abe3a322 Mon Sep 17 00:00:00 2001
From: Matt Nadareski <mnadareski@outlook.com>
Date: Mon, 25 Nov 2024 12:27:16 -0500
Subject: [PATCH] Implement EqualsExactly extension

---
 SabreTools.Matching.Test/ExtensionsTests.cs | 52 +++++++++++++++++++++
 SabreTools.Matching/Extensions.cs           | 30 +++++++++++-
 2 files changed, 81 insertions(+), 1 deletion(-)

diff --git a/SabreTools.Matching.Test/ExtensionsTests.cs b/SabreTools.Matching.Test/ExtensionsTests.cs
index b964529..da9b4c4 100644
--- a/SabreTools.Matching.Test/ExtensionsTests.cs
+++ b/SabreTools.Matching.Test/ExtensionsTests.cs
@@ -237,6 +237,58 @@ namespace SabreTools.Matching.Test
 
         #endregion
 
+        #region Equals Exactly
+
+        [Fact]
+        public void EqualsExactly_EmptyStack_NoMatches()
+        {
+            byte[] stack = [];
+            bool found = stack.EqualsExactly([0x01]);
+            Assert.False(found);
+        }
+
+        [Fact]
+        public void EqualsExactly_EmptyNeedle_NoMatches()
+        {
+            byte[] stack = [0x01];
+            bool found = stack.EqualsExactly(Array.Empty<byte>());
+            Assert.False(found);
+        }
+
+        [Fact]
+        public void EqualsExactly_ShorterNeedle_NoMatches()
+        {
+            byte[] stack = [0x01, 0x02];
+            bool found = stack.EqualsExactly([0x01]);
+            Assert.False(found);
+        }
+
+        [Fact]
+        public void EqualsExactly_LongerNeedle_NoMatches()
+        {
+            byte[] stack = [0x01];
+            bool found = stack.EqualsExactly([0x01, 0x02]);
+            Assert.False(found);
+        }
+
+        [Fact]
+        public void EqualsExactly_Matching_Matches()
+        {
+            byte[] stack = [0x01, 0x02];
+            bool found = stack.EqualsExactly([0x01, 0x02]);
+            Assert.True(found);
+        }
+
+        [Fact]
+        public void EqualsExactly_Mismatch_NoMatches()
+        {
+            byte[] stack = [0x01, 0x03];
+            bool found = stack.EqualsExactly([0x01, 0x02]);
+            Assert.False(found);
+        }
+
+        #endregion
+
         #region Starts With
 
         [Fact]
diff --git a/SabreTools.Matching/Extensions.cs b/SabreTools.Matching/Extensions.cs
index 0504518..1bc91b7 100644
--- a/SabreTools.Matching/Extensions.cs
+++ b/SabreTools.Matching/Extensions.cs
@@ -4,7 +4,6 @@ using SabreTools.Matching.Content;
 
 namespace SabreTools.Matching
 {
-    // TODO: Write SequenceEqual equivilent: EqualsExactly
     public static class Extensions
     {
         /// <summary>
@@ -137,6 +136,35 @@ namespace SabreTools.Matching
             return matcher.Match(stack, reverse: true);
         }
 
+        /// <summary>
+        /// Check if a byte array exactly matches another
+        /// </summary>
+        /// <param name="stack">Byte array to search within</param>
+        /// <param name="needle">Byte array representing the search value</param>
+        public static bool EqualsExactly(this byte[] stack, byte[] needle)
+        {
+            byte?[] nullableNeedle = Array.ConvertAll(needle, b => (byte?)b);
+            return EqualsExactly(stack, nullableNeedle);
+        }
+
+        /// <summary>
+        /// Check if a byte array exactly matches another
+        /// </summary>
+        /// <param name="stack">Byte array to search within</param>
+        /// <param name="needle">Byte array representing the search value</param>
+        public static bool EqualsExactly(this byte[] stack, byte?[] needle)
+        {
+            // If either set is null or empty
+            if (stack.Length == 0 || needle.Length == 0)
+                return false;
+
+            // If the needle is not the exact length of the stack
+            if (needle.Length != stack.Length)
+                return false;
+
+            return FirstPosition(stack, needle, start: 0, end: 1) == 0;
+        }
+
         /// <summary>
         /// Check if a byte array starts with another
         /// </summary>