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[FileTools] Switch external CRC32 algorithm class

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This commit is contained in:
Matt Nadareski
2016-09-01 21:17:51 -07:00
parent 6192242d5e
commit f83d0e6750
4 changed files with 152 additions and 125 deletions
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119
SabreTools.Helper/Tools/CRC32.cs
View File

@@ -1,119 +0,0 @@
// Copyright (c) Damien Guard. All rights reserved.
// Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License.
// You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0
// Originally published at http://damieng.com/blog/2006/08/08/calculating_crc32_in_c_and_net
using System;
using System.Collections.Generic;
using System.Security.Cryptography;
namespace DamienG.Security.Cryptography
{
/// <summary>
/// Implements a 32-bit CRC hash algorithm compatible with Zip etc.
/// </summary>
/// <remarks>
/// Crc32 should only be used for backward compatibility with older file formats
/// and algorithms. It is not secure enough for new applications.
/// If you need to call multiple times for the same data either use the HashAlgorithm
/// interface or remember that the result of one Compute call needs to be ~ (XOR) before
/// being passed in as the seed for the next Compute call.
/// </remarks>
public sealed class Crc32 : HashAlgorithm
{
public const UInt32 DefaultPolynomial = 0xedb88320u;
public const UInt32 DefaultSeed = 0xffffffffu;
static UInt32[] defaultTable;
readonly UInt32 seed;
readonly UInt32[] table;
UInt32 hash;
public Crc32()
: this(DefaultPolynomial, DefaultSeed)
{
}
public Crc32(UInt32 polynomial, UInt32 seed)
{
table = InitializeTable(polynomial);
this.seed = hash = seed;
}
public override void Initialize()
{
hash = seed;
}
protected override void HashCore(byte[] array, int ibStart, int cbSize)
{
hash = CalculateHash(table, hash, array, ibStart, cbSize);
}
protected override byte[] HashFinal()
{
var hashBuffer = UInt32ToBigEndianBytes(~hash);
HashValue = hashBuffer;
return hashBuffer;
}
public override int HashSize { get { return 32; } }
public static UInt32 Compute(byte[] buffer)
{
return Compute(DefaultSeed, buffer);
}
public static UInt32 Compute(UInt32 seed, byte[] buffer)
{
return Compute(DefaultPolynomial, seed, buffer);
}
public static UInt32 Compute(UInt32 polynomial, UInt32 seed, byte[] buffer)
{
return ~CalculateHash(InitializeTable(polynomial), seed, buffer, 0, buffer.Length);
}
static UInt32[] InitializeTable(UInt32 polynomial)
{
if (polynomial == DefaultPolynomial && defaultTable != null)
return defaultTable;
var createTable = new UInt32[256];
for (var i = 0; i < 256; i++)
{
var entry = (UInt32)i;
for (var j = 0; j < 8; j++)
if ((entry & 1) == 1)
entry = (entry >> 1) ^ polynomial;
else
entry = entry >> 1;
createTable[i] = entry;
}
if (polynomial == DefaultPolynomial)
defaultTable = createTable;
return createTable;
}
static UInt32 CalculateHash(UInt32[] table, UInt32 seed, IList<byte> buffer, int start, int size)
{
var crc = seed;
for (var i = start; i < size - start; i++)
crc = (crc >> 8) ^ table[buffer[i] ^ crc & 0xff];
return crc;
}
static byte[] UInt32ToBigEndianBytes(UInt32 uint32)
{
var result = BitConverter.GetBytes(uint32);
if (BitConverter.IsLittleEndian)
Array.Reverse(result);
return result;
}
}
}

10
SabreTools.Helper/Tools/FileTools.cs
View File

@@ -1,4 +1,4 @@
using DamienG.Security.Cryptography;
using CRC32;
using SharpCompress.Archive;
using SharpCompress.Archive.SevenZip;
using SharpCompress.Common;
@@ -608,7 +608,7 @@ namespace SabreTools.Helper
try
{
using (Crc32 crc = new Crc32())
using (OptimizedCRC crc = new OptimizedCRC())
using (MD5 md5 = MD5.Create())
using (SHA1 sha1 = SHA1.Create())
using (FileStream fs = File.OpenRead(input))
@@ -623,7 +623,7 @@ namespace SabreTools.Helper
int read;
while ((read = fs.Read(buffer, 0, buffer.Length)) > 0)
{
crc.TransformBlock(buffer, 0, read, buffer, 0);
crc.Update(buffer, 0, read);
if (!noMD5)
{
md5.TransformBlock(buffer, 0, read, buffer, 0);
@@ -634,8 +634,8 @@ namespace SabreTools.Helper
}
}
crc.TransformFinalBlock(buffer, 0, 0);
rom.HashData.CRC = BitConverter.ToString(crc.Hash).Replace("-", "").ToLowerInvariant();
crc.Update(buffer, 0, 0);
rom.HashData.CRC = crc.Value.ToString("X8").ToLowerInvariant();
if (!noMD5)
{