Padding fix, checksum fix

4 files changed, 145 insertions, 79 deletions

diff --git a/Crc32.cs b/Crc32.cs
new file mode 100644
index 0000000..33acf83
--- /dev/null
+++ b/Crc32.cs
@@ -0,0 +1,65 @@
+using System;
+using System.Security.Cryptography;
+
+namespace com.clusterrr.Famicom.Containers
+{
+    /// <summary>
+    /// CRC32 calculator
+    /// </summary>
+    internal class Crc32 : HashAlgorithm
+    {
+        private readonly uint[] table = new uint[256];
+        private uint crc = 0xFFFFFFFF;
+
+        public Crc32()
+        {
+            // Calculate table
+            uint poly = 0xedb88320;
+            uint temp;
+            for (uint i = 0; i < table.Length; ++i)
+            {
+                temp = i;
+                for (int j = 8; j > 0; --j)
+                {
+                    if ((temp & 1) == 1)
+                    {
+                        temp = (uint)((temp >> 1) ^ poly);
+                    }
+                    else
+                    {
+                        temp >>= 1;
+                    }
+                }
+                table[i] = temp;
+            }
+        }
+
+        public override void Initialize()
+        {
+        }
+
+        public override bool CanReuseTransform => false;
+
+        protected override void HashCore(byte[] array, int ibStart, int cbSize)
+        {
+            while (cbSize > 0)
+            {
+                var pos = ibStart;
+                byte index = (byte)(((crc) & 0xff) ^ array[pos]);
+                crc = (crc >> 8) ^ table[index];
+                ibStart++;
+                cbSize--;
+            }
+        }
+
+        protected override byte[] HashFinal()
+        {
+            return BitConverter.GetBytes(~crc);
+        }
+
+        public override bool CanTransformMultipleBlocks => true;
+        public override byte[] Hash => BitConverter.GetBytes(~crc);
+        public override int HashSize => 32;
+
+    }
+}
diff --git a/Crc32Calculator.cs b/Crc32Calculator.cs
deleted file mode 100644
index 3c6e0c7..0000000
--- a/Crc32Calculator.cs
+++ /dev/null
@@ -1,60 +0,0 @@
-namespace com.clusterrr.Famicom.Containers

-{

-    /// <summary>

-    /// CRC32 calculator

-    /// </summary>

-    internal static class Crc32Calculator

-    {

-        static readonly uint[] table = new uint[256];

-

-        static Crc32Calculator()

-        {

-            // Calculate table

-            uint poly = 0xedb88320;

-            uint temp;

-            for (uint i = 0; i < table.Length; ++i)

-            {

-                temp = i;

-                for (int j = 8; j > 0; --j)

-                {

-                    if ((temp & 1) == 1)

-                    {

-                        temp = (uint)((temp >> 1) ^ poly);

-                    }

-                    else

-                    {

-                        temp >>= 1;

-                    }

-                }

-                table[i] = temp;

-            }

-        }

-

-        /// <summary>

-        /// Calculate CRC32 checksum

-        /// </summary>

-        /// <param name="data">Input data</param>

-        /// <param name="offset">Data offset</param>

-        /// <param name="length">Length</param>

-        /// <returns>CRC32 checksum</returns>

-        public static uint CalculateCRC32(byte[] data, int offset, int length)

-        {

-            // Calculate CRC32

-            uint crc = 0xffffffff;

-            for (int i = offset; length > 0; i++, length--)

-            {

-                byte index = (byte)(((crc) & 0xff) ^ data[i]);

-                crc = (crc >> 8) ^ table[index];

-            }

-            return ~crc;

-        }

-

-        /// <summary>

-        /// Calculate CRC32 checksum

-        /// </summary>

-        /// <param name="data">Input data</param>

-        /// <returns>CRC32 checksum</returns>

-        public static uint CalculateCRC32(byte[] data)

-            => CalculateCRC32(data, 0, data.Length);

-    }

-}

diff --git a/NesFile.cs b/NesFile.cs
index 94f18b7..ad45117 100644
--- a/NesFile.cs
+++ b/NesFile.cs
@@ -752,7 +752,9 @@ namespace com.clusterrr.Famicom.Containers
                     if (trainer.Length < 512) data.AddRange(Enumerable.Repeat<byte>(0xFF, (int)512 - trainer.Length));

                 }

                 data.AddRange(prg);

+                data.AddRange(Enumerable.Repeat<byte>(byte.MaxValue, (int)prgSizePadded - prg.Length));

                 data.AddRange(chr);

+                data.AddRange(Enumerable.Repeat<byte>(byte.MaxValue, (int)chrSizePadded - chr.Length));

             }

             else if (Version == iNesVersion.NES20)

             {

@@ -846,12 +848,12 @@ namespace com.clusterrr.Famicom.Containers
                 if (trainer.Length > 0)

                 {

                     data.AddRange(trainer);

-                    if (trainer.Length < 512) data.AddRange(Enumerable.Repeat<byte>(0xFF, (int)512 - trainer.Length));

+                    if (trainer.Length < 512) data.AddRange(Enumerable.Repeat(byte.MaxValue, (int)512 - trainer.Length));

                 }

                 data.AddRange(prg);

-                data.AddRange(Enumerable.Repeat<byte>(0xFF, (int)prgSizePadded - prg.Length));

+                data.AddRange(Enumerable.Repeat(byte.MaxValue, (int)prgSizePadded - prg.Length));

                 data.AddRange(chr);

-                data.AddRange(Enumerable.Repeat<byte>(0xFF, (int)chrSizePadded - chr.Length));

+                data.AddRange(Enumerable.Repeat(byte.MaxValue, (int)chrSizePadded - chr.Length));

                 if (MiscellaneousROMsCount > 0 || miscellaneousROM.Length > 0)

                 {

                     if (MiscellaneousROMsCount == 0)

@@ -929,15 +931,46 @@ namespace com.clusterrr.Famicom.Containers
         /// <returns>MD5 checksum for all PRG and CHR data</returns>

         public byte[] CalculateMD5()

         {

-            var md5 = MD5.Create();

-            var alldata = Enumerable.Concat(prg ?? Array.Empty<byte>(), chr ?? Array.Empty<byte>()).ToArray();

-            return md5.ComputeHash(alldata);

+            int prgSizeUpPow2 = 1;

+            int chrSizeUpPow2 = 1;

+            while (prgSizeUpPow2 < PRG.Length) prgSizeUpPow2 *= 2;

+            if (CHR.Length == 0)

+                chrSizeUpPow2 = 0;

+            else

+                while (chrSizeUpPow2 < CHR.Length) chrSizeUpPow2 *= 2;

+            using (var md5 = MD5.Create())

+            {

+                md5.TransformBlock(prg, 0, prg.Length, null, 0);

+                md5.TransformBlock(Enumerable.Repeat<byte>(byte.MaxValue, prgSizeUpPow2 - prg.Length).ToArray(), 0, prgSizeUpPow2 - prg.Length, null, 0);

+                md5.TransformBlock(chr, 0, chr.Length, null, 0);

+                md5.TransformBlock(Enumerable.Repeat<byte>(byte.MaxValue, chrSizeUpPow2 - chr.Length).ToArray(), 0, chrSizeUpPow2 - chr.Length, null, 0);

+                md5.TransformFinalBlock(new byte[0], 0, 0);

+                return md5.Hash;

+            }

         }

 

         /// <summary>

         /// Calculate CRC32 checksum of ROM (CHR+PRG without header)

         /// </summary>

         /// <returns>CRC32 checksum for all PRG and CHR data</returns>

-        public uint CalculateCRC32() => Crc32Calculator.CalculateCRC32(Enumerable.Concat(prg ?? Array.Empty<byte>(), chr ?? Array.Empty<byte>()).ToArray());

+        public uint CalculateCRC32()

+        {

+            int prgSizeUpPow2 = 1;

+            int chrSizeUpPow2 = 1;

+            while (prgSizeUpPow2 < PRG.Length) prgSizeUpPow2 *= 2;

+            if (CHR.Length == 0)

+                chrSizeUpPow2 = 0;

+            else

+                while (chrSizeUpPow2 < CHR.Length) chrSizeUpPow2 *= 2;

+            using (var crc32 = new Crc32())

+            {

+                crc32.TransformBlock(prg, 0, prg.Length, null, 0);

+                crc32.TransformBlock(Enumerable.Repeat<byte>(byte.MaxValue, prgSizeUpPow2 - prg.Length).ToArray(), 0, prgSizeUpPow2 - prg.Length, null, 0);

+                crc32.TransformBlock(chr, 0, chr.Length, null, 0);

+                crc32.TransformBlock(Enumerable.Repeat<byte>(byte.MaxValue, chrSizeUpPow2 - chr.Length).ToArray(), 0, chrSizeUpPow2 - chr.Length, null, 0);

+                crc32.TransformFinalBlock(new byte[0], 0, 0);

+                return BitConverter.ToUInt32(crc32.Hash, 0);

+            }

+        }

     }

 }

diff --git a/UnifFile.cs b/UnifFile.cs
index a39e58d..0a0f33c 100644
--- a/UnifFile.cs
+++ b/UnifFile.cs
@@ -610,14 +610,16 @@ namespace com.clusterrr.Famicom.Containers
             foreach (var kv in this.Where(kv => kv.Key.StartsWith(PREFIX_PRG)))

             {

                 var num = kv.Key[3];

-                var crc32 = Crc32Calculator.CalculateCRC32(kv.Value);

-                this[$"PCK{num}"] = BitConverter.GetBytes(crc32);

+                using var crc32 = new Crc32();

+                var crc32sum = crc32.ComputeHash(kv.Value);

+                this[$"PCK{num}"] = crc32sum;

             }

             foreach (var kv in this.Where(kv => kv.Key.StartsWith(PREFIX_CHR)))

             {

                 var num = kv.Key[3];

-                var crc32 = Crc32Calculator.CalculateCRC32(kv.Value);

-                this[$"CCK{num}"] = BitConverter.GetBytes(crc32);

+                using var crc32 = new Crc32();

+                var crc32sum = crc32.ComputeHash(kv.Value);

+                this[$"CCK{num}"] = crc32sum;

             }

         }

 

@@ -627,10 +629,22 @@ namespace com.clusterrr.Famicom.Containers
         /// <returns>MD5 checksum for all PRG and CHR data</returns>

         public byte[] CalculateMD5()

         {

-            var md5 = MD5.Create();

-            var alldata = Enumerable.Concat(fields.Where(k => k.Key.StartsWith(PREFIX_PRG)).OrderBy(k => k.Key).SelectMany(i => i.Value),

-                                  fields.Where(k => k.Key.StartsWith(PREFIX_CHR)).OrderBy(k => k.Key).SelectMany(i => i.Value)).ToArray();

-            return md5.ComputeHash(alldata);

+            using var md5 = MD5.Create();

+            foreach(var kv in fields.Where(k => k.Key.StartsWith(PREFIX_PRG)).OrderBy(k => k.Key)

+                .Concat(fields.Where(k => k.Key.StartsWith(PREFIX_CHR)).OrderBy(k => k.Key)))

+            {

+                var v = kv.Value;

+                int sizeUpPow2 = 0;

+                if (v.Length > 0)

+                {

+                    sizeUpPow2 = 1;

+                    while (sizeUpPow2 < v.Length) sizeUpPow2 *= 2;

+                }

+                md5.TransformBlock(v, 0, v.Length, null, 0);

+                md5.TransformBlock(Enumerable.Repeat<byte>(byte.MaxValue, sizeUpPow2 - v.Length).ToArray(), 0, sizeUpPow2 - v.Length, null, 0);

+            }

+            md5.TransformFinalBlock(new byte[0], 0, 0);

+            return md5.Hash;

         }

 

         /// <summary>

@@ -638,10 +652,24 @@ namespace com.clusterrr.Famicom.Containers
         /// </summary>

         /// <returns>CRC32 checksum for all PRG and CHR data</returns>

         public uint CalculateCRC32()

-            => Crc32Calculator.CalculateCRC32(

-                Enumerable.Concat(fields.Where(k => k.Key.StartsWith(PREFIX_PRG)).OrderBy(k => k.Key).SelectMany(i => i.Value),

-                                  fields.Where(k => k.Key.StartsWith(PREFIX_CHR)).OrderBy(k => k.Key).SelectMany(i => i.Value)).ToArray()

-            );

+        {

+            using var crc32 = new Crc32();

+            foreach (var kv in fields.Where(k => k.Key.StartsWith(PREFIX_PRG)).OrderBy(k => k.Key)

+                .Concat(fields.Where(k => k.Key.StartsWith(PREFIX_CHR)).OrderBy(k => k.Key)))

+            {

+                var v = kv.Value;

+                int sizeUpPow2 = 0;

+                if (v.Length > 0)

+                {

+                    sizeUpPow2 = 1;

+                    while (sizeUpPow2 < v.Length) sizeUpPow2 *= 2;

+                }

+                crc32.TransformBlock(v, 0, v.Length, null, 0);

+                crc32.TransformBlock(Enumerable.Repeat<byte>(byte.MaxValue, sizeUpPow2 - v.Length).ToArray(), 0, sizeUpPow2 - v.Length, null, 0);

+            }

+            crc32.TransformFinalBlock(new byte[0], 0, 0);

+            return BitConverter.ToUInt32(crc32.Hash, 0);

+        }

 

         /// <summary>

         /// Default game controller(s)