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Corrected CRC algorithms

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This commit is contained in:
Natalia Portillo
2015-02-02 18:49:29 +00:00
parent 47eb235e1a
commit a1520d6b41
3 changed files with 20 additions and 11 deletions
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14
SharpHash/Checksums/CRC16Context.cs
View File

@@ -30,8 +30,8 @@ namespace SharpHash.Checksums
/// </summary>
public class CRC16Context
{
const UInt16 crc16Poly = 0x8408;
const UInt16 crc16Seed = 0xFFFF;
const UInt16 crc16Poly = 0xA001;
const UInt16 crc16Seed = 0x0000;
UInt16[] table;
UInt16 hashInt;
@@ -64,7 +64,7 @@ namespace SharpHash.Checksums
public void Update(byte[] data, uint len)
{
for (int i = 0; i < len; i++)
hashInt = (ushort)((hashInt >> 8) ^ table[data[i] ^ hashInt & 0xff]);
hashInt = (ushort)((hashInt >> 8) ^ table[data[i] ^ (hashInt & 0xFF)]);
}
/// <summary>
@@ -82,6 +82,7 @@ namespace SharpHash.Checksums
public byte[] Final()
{
hashInt ^= crc16Seed;
BigEndianBitConverter.IsLittleEndian = BitConverter.IsLittleEndian;
return BigEndianBitConverter.GetBytes(hashInt);
}
@@ -93,6 +94,7 @@ namespace SharpHash.Checksums
hashInt ^= crc16Seed;
StringBuilder crc16Output = new StringBuilder();
BigEndianBitConverter.IsLittleEndian = BitConverter.IsLittleEndian;
for (int i = 0; i < BigEndianBitConverter.GetBytes(hashInt).Length; i++)
{
crc16Output.Append(BigEndianBitConverter.GetBytes(hashInt)[i].ToString("x2"));
@@ -140,7 +142,8 @@ namespace SharpHash.Checksums
for (int i = 0; i < fileStream.Length; i++)
localhashInt = (ushort)((localhashInt >> 8) ^ localTable[fileStream.ReadByte() ^ localhashInt & 0xff]);
hash = BitConverter.GetBytes(localhashInt);
BigEndianBitConverter.IsLittleEndian = BitConverter.IsLittleEndian;
hash = BigEndianBitConverter.GetBytes(localhashInt);
StringBuilder crc16Output = new StringBuilder();
@@ -193,7 +196,8 @@ namespace SharpHash.Checksums
for (int i = 0; i < len; i++)
localhashInt = (ushort)((localhashInt >> 8) ^ localTable[data[i] ^ localhashInt & 0xff]);
hash = BitConverter.GetBytes(localhashInt);
BigEndianBitConverter.IsLittleEndian = BitConverter.IsLittleEndian;
hash = BigEndianBitConverter.GetBytes(localhashInt);
StringBuilder crc16Output = new StringBuilder();

12
SharpHash/Checksums/CRC32Context.cs
View File

@@ -30,12 +30,8 @@ namespace SharpHash.Checksums
/// </summary>
public class CRC32Context
{
//const UInt32 crc32Poly = 0xEDB88320;
//const UInt32 crc32Seed = 0xFFFFFFFF;
const UInt32 crc32Poly = 0xD8018001;
const UInt32 crc32Seed = 0x00000000;
const UInt32 crc32Poly = 0xEDB88320;
const UInt32 crc32Seed = 0xFFFFFFFF;
UInt32[] table;
UInt32 hashInt;
@@ -86,6 +82,7 @@ namespace SharpHash.Checksums
public byte[] Final()
{
hashInt ^= crc32Seed;
BigEndianBitConverter.IsLittleEndian = BitConverter.IsLittleEndian;
return BigEndianBitConverter.GetBytes(hashInt);
}
@@ -97,6 +94,7 @@ namespace SharpHash.Checksums
hashInt ^= crc32Seed;
StringBuilder crc32Output = new StringBuilder();
BigEndianBitConverter.IsLittleEndian = BitConverter.IsLittleEndian;
for (int i = 0; i < BigEndianBitConverter.GetBytes(hashInt).Length; i++)
{
crc32Output.Append(BigEndianBitConverter.GetBytes(hashInt)[i].ToString("x2"));
@@ -144,6 +142,7 @@ namespace SharpHash.Checksums
for (int i = 0; i < fileStream.Length; i++)
localhashInt = (localhashInt >> 8) ^ localTable[fileStream.ReadByte() ^ localhashInt & 0xff];
BigEndianBitConverter.IsLittleEndian = BitConverter.IsLittleEndian;
hash = BitConverter.GetBytes(localhashInt);
StringBuilder crc32Output = new StringBuilder();
@@ -197,6 +196,7 @@ namespace SharpHash.Checksums
for (int i = 0; i < len; i++)
localhashInt = (localhashInt >> 8) ^ localTable[data[i] ^ localhashInt & 0xff];
BigEndianBitConverter.IsLittleEndian = BitConverter.IsLittleEndian;
hash = BitConverter.GetBytes(localhashInt);
StringBuilder crc32Output = new StringBuilder();

5
SharpHash/Checksums/CRC64Context.cs
View File

@@ -65,6 +65,7 @@ namespace SharpHash.Checksums
{
for (int i = 0; i < len; i++)
hashInt = (hashInt >> 8) ^ table[data[i] ^ hashInt & 0xff];
}
/// <summary>
@@ -82,6 +83,7 @@ namespace SharpHash.Checksums
public byte[] Final()
{
hashInt ^= crc64Seed;
BigEndianBitConverter.IsLittleEndian = BigEndianBitConverter.IsLittleEndian;
return BigEndianBitConverter.GetBytes(hashInt);
}
@@ -93,6 +95,7 @@ namespace SharpHash.Checksums
hashInt ^= crc64Seed;
StringBuilder crc64Output = new StringBuilder();
BigEndianBitConverter.IsLittleEndian = BigEndianBitConverter.IsLittleEndian;
for (int i = 0; i < BigEndianBitConverter.GetBytes(hashInt).Length; i++)
{
crc64Output.Append(BigEndianBitConverter.GetBytes(hashInt)[i].ToString("x2"));
@@ -140,6 +143,7 @@ namespace SharpHash.Checksums
for (int i = 0; i < fileStream.Length; i++)
localhashInt = (localhashInt >> 8) ^ localTable[(ulong)fileStream.ReadByte() ^ localhashInt & (ulong)0xff];
BigEndianBitConverter.IsLittleEndian = BigEndianBitConverter.IsLittleEndian;
hash = BitConverter.GetBytes(localhashInt);
StringBuilder crc64Output = new StringBuilder();
@@ -193,6 +197,7 @@ namespace SharpHash.Checksums
for (int i = 0; i < len; i++)
localhashInt = (localhashInt >> 8) ^ localTable[data[i] ^ localhashInt & 0xff];
BigEndianBitConverter.IsLittleEndian = BigEndianBitConverter.IsLittleEndian;
hash = BitConverter.GetBytes(localhashInt);
StringBuilder crc64Output = new StringBuilder();