From fb470cad7c539e5a2ef1bb3c8571a73e3ec709b5 Mon Sep 17 00:00:00 2001
From: Natalia Portillo <claunia@claunia.com>
Date: Mon, 11 Feb 2019 01:39:58 +0000
Subject: [PATCH] Add ByteInputOutputTableCodingLoop class.

---
 .../ByteInputOutputTableCodingLoop.cs         | 49 +++++++++++++++++++
 .../Claunia.ReedSolomon.csproj                |  1 +
 2 files changed, 50 insertions(+)
 create mode 100644 Claunia.ReedSolomon/ByteInputOutputTableCodingLoop.cs

diff --git a/Claunia.ReedSolomon/ByteInputOutputTableCodingLoop.cs b/Claunia.ReedSolomon/ByteInputOutputTableCodingLoop.cs
new file mode 100644
index 0000000..e50c4a2
--- /dev/null
+++ b/Claunia.ReedSolomon/ByteInputOutputTableCodingLoop.cs
@@ -0,0 +1,49 @@
+/**
+ * One specific ordering/nesting of the coding loops.
+ *
+ * Copyright 2015, Backblaze, Inc.  All rights reserved.
+ * Copyright © 2019 Natalia Portillo
+ */
+
+namespace Claunia.ReedSolomon
+{
+    public class ByteInputOutputTableCodingLoop : CodingLoopBase
+    {
+        public override void CodeSomeShards(byte[][] matrixRows, byte[][] inputs, int inputCount, byte[][] outputs,
+                                            int outputCount, int offset, int byteCount)
+        {
+            byte[][] table = Galois.MULTIPLICATION_TABLE;
+
+            for(int iByte = offset; iByte < offset + byteCount; iByte++)
+            {
+                {
+                    int    iInput     = 0;
+                    byte[] inputShard = inputs[iInput];
+                    byte   inputByte  = inputShard[iByte];
+
+                    for(int iOutput = 0; iOutput < outputCount; iOutput++)
+                    {
+                        byte[] outputShard  = outputs[iOutput];
+                        byte[] matrixRow    = matrixRows[iOutput];
+                        byte[] multTableRow = table[matrixRow[iInput] & 0xFF];
+                        outputShard[iByte] = multTableRow[inputByte & 0xFF];
+                    }
+                }
+
+                for(int iInput = 1; iInput < inputCount; iInput++)
+                {
+                    byte[] inputShard = inputs[iInput];
+                    byte   inputByte  = inputShard[iByte];
+
+                    for(int iOutput = 0; iOutput < outputCount; iOutput++)
+                    {
+                        byte[] outputShard  = outputs[iOutput];
+                        byte[] matrixRow    = matrixRows[iOutput];
+                        byte[] multTableRow = table[matrixRow[iInput] & 0xFF];
+                        outputShard[iByte] ^= multTableRow[inputByte & 0xFF];
+                    }
+                }
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git a/Claunia.ReedSolomon/Claunia.ReedSolomon.csproj b/Claunia.ReedSolomon/Claunia.ReedSolomon.csproj
index 370a59c..921c6fc 100644
--- a/Claunia.ReedSolomon/Claunia.ReedSolomon.csproj
+++ b/Claunia.ReedSolomon/Claunia.ReedSolomon.csproj
@@ -39,6 +39,7 @@
     </ItemGroup>
     <ItemGroup>
         <Compile Include="ByteInputOutputExpCodingLoop.cs" />
+        <Compile Include="ByteInputOutputTableCodingLoop.cs" />
         <Compile Include="CodingLoopBase.cs" />
         <Compile Include="Galois.cs" />
         <Compile Include="ICodingLoop.cs" />