aaru-dps/Aaru.Checksums
1
0
Fork 0
mirror of https://github.com/aaru-dps/Aaru.Checksums.git synced 2025-12-16 19:24:29 +00:00
Code Issues Packages Projects Releases Wiki Activity

General cleanup and refactor.

Browse Source
This commit is contained in:
Natalia Portillo
2022-03-07 07:36:42 +00:00
parent db8c5c6a53
commit 19c7f3d4ff
22 changed files with 1076 additions and 1544 deletions
Download Patch File Download Diff File Expand all files Collapse all files

530
SpamSumContext.cs
View File

@@ -39,13 +39,13 @@
// http://www.samba.org/ftp/unpacked/junkcode/spamsum/
// http://ssdeep.sf.net/
namespace Aaru.Checksums;
using System;
using System.Runtime.CompilerServices;
using System.Text;
using Aaru.CommonTypes.Interfaces;
namespace Aaru.Checksums;
/// <inheritdoc />
/// <summary>Implements the SpamSum fuzzy hashing algorithm.</summary>
public sealed class SpamSumContext : IChecksum
@@ -56,7 +56,7 @@ public sealed class SpamSumContext : IChecksum
const uint HASH_INIT = 0x28021967;
const uint NUM_BLOCKHASHES = 31;
const uint SPAMSUM_LENGTH = 64;
const uint FUZZY_MAX_RESULT = (2 * SPAMSUM_LENGTH) + 20;
const uint FUZZY_MAX_RESULT = 2 * SPAMSUM_LENGTH + 20;
//"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
readonly byte[] _b64 =
@@ -77,7 +77,7 @@ public sealed class SpamSumContext : IChecksum
Bh = new BlockhashContext[NUM_BLOCKHASHES]
};
for(int i = 0; i < NUM_BLOCKHASHES; i++)
for(var i = 0; i < NUM_BLOCKHASHES; i++)
_self.Bh[i].Digest = new byte[SPAMSUM_LENGTH];
_self.Bhstart = 0;
@@ -99,7 +99,7 @@ public sealed class SpamSumContext : IChecksum
{
_self.TotalSize += len;
for(int i = 0; i < len; i++)
for(var i = 0; i < len; i++)
fuzzy_engine_step(data[i]);
}
@@ -232,295 +232,295 @@ public sealed class SpamSumContext : IChecksum
/* Once this condition is false for one bs, it is
* automatically false for all further bs. I.e. if
* h === -1 (mod 2*bs) then h === -1 (mod bs). */
break;
break;
/* We have hit a reset point. We now emit hashes which are
* based on all characters in the piece of the message between
* the last reset point and this one */
if(0 == _self.Bh[i].Dlen)
fuzzy_try_fork_blockhash();
/* We have hit a reset point. We now emit hashes which are
* based on all characters in the piece of the message between
* the last reset point and this one */
if(0 == _self.Bh[i].Dlen)
fuzzy_try_fork_blockhash();
_self.Bh[i].Digest[_self.Bh[i].Dlen] = _b64[_self.Bh[i].H % 64];
_self.Bh[i].Halfdigest = _b64[_self.Bh[i].Halfh % 64];
_self.Bh[i].Digest[_self.Bh[i].Dlen] = _b64[_self.Bh[i].H % 64];
_self.Bh[i].Halfdigest = _b64[_self.Bh[i].Halfh % 64];
if(_self.Bh[i].Dlen < SPAMSUM_LENGTH - 1)
if(_self.Bh[i].Dlen < SPAMSUM_LENGTH - 1)
{
/* We can have a problem with the tail overflowing. The
* easiest way to cope with this is to only reset the
* normal hash if we have room for more characters in
* our signature. This has the effect of combining the
* last few pieces of the message into a single piece
* */
_self.Bh[i].Digest[++_self.Bh[i].Dlen] = 0;
_self.Bh[i].H = HASH_INIT;
if(_self.Bh[i].Dlen >= SPAMSUM_LENGTH / 2)
continue;
_self.Bh[i].Halfh = HASH_INIT;
_self.Bh[i].Halfdigest = 0;
}
else
fuzzy_try_reduce_blockhash();
}
}
// CLAUNIA: Flags seems to never be used in ssdeep, so I just removed it for code simplicity
[MethodImpl(MethodImplOptions.AggressiveInlining)]
void FuzzyDigest(out byte[] result)
{
var sb = new StringBuilder();
uint bi = _self.Bhstart;
uint h = roll_sum();
var remain = (int)(FUZZY_MAX_RESULT - 1); /* Exclude terminating '\0'. */
result = new byte[FUZZY_MAX_RESULT];
/* Verify that our elimination was not overeager. */
if(!(bi == 0 || (ulong)SSDEEP_BS(bi) / 2 * SPAMSUM_LENGTH < _self.TotalSize))
throw new Exception("Assertion failed");
int resultOff;
/* Initial blocksize guess. */
while((ulong)SSDEEP_BS(bi) * SPAMSUM_LENGTH < _self.TotalSize)
{
++bi;
if(bi >= NUM_BLOCKHASHES)
throw new OverflowException("The input exceeds data types.");
}
/* Adapt blocksize guess to actual digest length. */
while(bi >= _self.Bhend)
--bi;
while(bi > _self.Bhstart &&
_self.Bh[bi].Dlen < SPAMSUM_LENGTH / 2)
--bi;
if(bi > 0 &&
_self.Bh[bi].Dlen < SPAMSUM_LENGTH / 2)
throw new Exception("Assertion failed");
sb.AppendFormat("{0}:", SSDEEP_BS(bi));
int i = Encoding.ASCII.GetBytes(sb.ToString()).Length;
if(i <= 0)
/* Maybe snprintf has set errno here? */
throw new OverflowException("The input exceeds data types.");
if(i >= remain)
throw new Exception("Assertion failed");
remain -= i;
Array.Copy(Encoding.ASCII.GetBytes(sb.ToString()), 0, result, 0, i);
resultOff = i;
i = (int)_self.Bh[bi].Dlen;
if(i > remain)
throw new Exception("Assertion failed");
Array.Copy(_self.Bh[bi].Digest, 0, result, resultOff, i);
resultOff += i;
remain -= i;
if(h != 0)
{
if(remain <= 0)
throw new Exception("Assertion failed");
result[resultOff] = _b64[_self.Bh[bi].H % 64];
if(i < 3 ||
result[resultOff] != result[resultOff - 1] ||
result[resultOff] != result[resultOff - 2] ||
result[resultOff] != result[resultOff - 3])
{
++resultOff;
--remain;
}
}
else if(_self.Bh[bi].Digest[i] != 0)
{
if(remain <= 0)
throw new Exception("Assertion failed");
result[resultOff] = _self.Bh[bi].Digest[i];
if(i < 3 ||
result[resultOff] != result[resultOff - 1] ||
result[resultOff] != result[resultOff - 2] ||
result[resultOff] != result[resultOff - 3])
{
++resultOff;
--remain;
}
}
if(remain <= 0)
throw new Exception("Assertion failed");
result[resultOff++] = 0x3A; // ':'
--remain;
if(bi < _self.Bhend - 1)
{
++bi;
i = (int)_self.Bh[bi].Dlen;
if(i > remain)
throw new Exception("Assertion failed");
Array.Copy(_self.Bh[bi].Digest, 0, result, resultOff, i);
resultOff += i;
remain -= i;
if(h != 0)
{
if(remain <= 0)
throw new Exception("Assertion failed");
h = _self.Bh[bi].Halfh;
result[resultOff] = _b64[h % 64];
if(i < 3 ||
result[resultOff] != result[resultOff - 1] ||
result[resultOff] != result[resultOff - 2] ||
result[resultOff] != result[resultOff - 3])
{
/* We can have a problem with the tail overflowing. The
* easiest way to cope with this is to only reset the
* normal hash if we have room for more characters in
* our signature. This has the effect of combining the
* last few pieces of the message into a single piece
* */
_self.Bh[i].Digest[++_self.Bh[i].Dlen] = 0;
_self.Bh[i].H = HASH_INIT;
if(_self.Bh[i].Dlen >= SPAMSUM_LENGTH / 2)
continue;
_self.Bh[i].Halfh = HASH_INIT;
_self.Bh[i].Halfdigest = 0;
}
else
fuzzy_try_reduce_blockhash();
}
++resultOff;
--remain;
}
}
else
{
i = _self.Bh[bi].Halfdigest;
// CLAUNIA: Flags seems to never be used in ssdeep, so I just removed it for code simplicity
[MethodImpl(MethodImplOptions.AggressiveInlining)]
void FuzzyDigest(out byte[] result)
if(i != 0)
{
var sb = new StringBuilder();
uint bi = _self.Bhstart;
uint h = roll_sum();
int remain = (int)(FUZZY_MAX_RESULT - 1); /* Exclude terminating '\0'. */
result = new byte[FUZZY_MAX_RESULT];
/* Verify that our elimination was not overeager. */
if(!(bi == 0 || (ulong)SSDEEP_BS(bi) / 2 * SPAMSUM_LENGTH < _self.TotalSize))
throw new Exception("Assertion failed");
int resultOff;
/* Initial blocksize guess. */
while((ulong)SSDEEP_BS(bi) * SPAMSUM_LENGTH < _self.TotalSize)
{
++bi;
if(bi >= NUM_BLOCKHASHES)
throw new OverflowException("The input exceeds data types.");
}
/* Adapt blocksize guess to actual digest length. */
while(bi >= _self.Bhend)
--bi;
while(bi > _self.Bhstart &&
_self.Bh[bi].Dlen < SPAMSUM_LENGTH / 2)
--bi;
if(bi > 0 &&
_self.Bh[bi].Dlen < SPAMSUM_LENGTH / 2)
throw new Exception("Assertion failed");
sb.AppendFormat("{0}:", SSDEEP_BS(bi));
int i = Encoding.ASCII.GetBytes(sb.ToString()).Length;
if(i <= 0)
/* Maybe snprintf has set errno here? */
throw new OverflowException("The input exceeds data types.");
if(i >= remain)
throw new Exception("Assertion failed");
remain -= i;
Array.Copy(Encoding.ASCII.GetBytes(sb.ToString()), 0, result, 0, i);
resultOff = i;
i = (int)_self.Bh[bi].Dlen;
if(i > remain)
throw new Exception("Assertion failed");
Array.Copy(_self.Bh[bi].Digest, 0, result, resultOff, i);
resultOff += i;
remain -= i;
if(h != 0)
{
if(remain <= 0)
throw new Exception("Assertion failed");
result[resultOff] = _b64[_self.Bh[bi].H % 64];
if(i < 3 ||
result[resultOff] != result[resultOff - 1] ||
result[resultOff] != result[resultOff - 2] ||
result[resultOff] != result[resultOff - 3])
{
++resultOff;
--remain;
}
}
else if(_self.Bh[bi].Digest[i] != 0)
{
if(remain <= 0)
throw new Exception("Assertion failed");
result[resultOff] = _self.Bh[bi].Digest[i];
if(i < 3 ||
result[resultOff] != result[resultOff - 1] ||
result[resultOff] != result[resultOff - 2] ||
result[resultOff] != result[resultOff - 3])
{
++resultOff;
--remain;
}
}
if(remain <= 0)
throw new Exception("Assertion failed");
result[resultOff++] = 0x3A; // ':'
--remain;
result[resultOff] = (byte)i;
if(bi < _self.Bhend - 1)
if(i < 3 ||
result[resultOff] != result[resultOff - 1] ||
result[resultOff] != result[resultOff - 2] ||
result[resultOff] != result[resultOff - 3])
{
++bi;
i = (int)_self.Bh[bi].Dlen;
if(i > remain)
throw new Exception("Assertion failed");
Array.Copy(_self.Bh[bi].Digest, 0, result, resultOff, i);
resultOff += i;
remain -= i;
if(h != 0)
{
if(remain <= 0)
throw new Exception("Assertion failed");
h = _self.Bh[bi].Halfh;
result[resultOff] = _b64[h % 64];
if(i < 3 ||
result[resultOff] != result[resultOff - 1] ||
result[resultOff] != result[resultOff - 2] ||
result[resultOff] != result[resultOff - 3])
{
++resultOff;
--remain;
}
}
else
{
i = _self.Bh[bi].Halfdigest;
if(i != 0)
{
if(remain <= 0)
throw new Exception("Assertion failed");
result[resultOff] = (byte)i;
if(i < 3 ||
result[resultOff] != result[resultOff - 1] ||
result[resultOff] != result[resultOff - 2] ||
result[resultOff] != result[resultOff - 3])
{
++resultOff;
--remain;
}
}
}
}
else if(h != 0)
{
if(_self.Bh[bi].Dlen != 0)
throw new Exception("Assertion failed");
if(remain <= 0)
throw new Exception("Assertion failed");
result[resultOff++] = _b64[_self.Bh[bi].H % 64];
/* No need to bother with FUZZY_FLAG_ELIMSEQ, because this
* digest has length 1. */
++resultOff;
--remain;
}
result[resultOff] = 0;
}
}
}
else if(h != 0)
{
if(_self.Bh[bi].Dlen != 0)
throw new Exception("Assertion failed");
/// <summary>Gets the hash of a file</summary>
/// <param name="filename">File path.</param>
public static byte[] File(string filename) =>
throw new NotImplementedException("SpamSum does not have a binary representation.");
if(remain <= 0)
throw new Exception("Assertion failed");
/// <summary>Gets the hash of a file in hexadecimal and as a byte array.</summary>
/// <param name="filename">File path.</param>
/// <param name="hash">Byte array of the hash value.</param>
public static string File(string filename, out byte[] hash) =>
throw new NotImplementedException("Not yet implemented.");
result[resultOff++] = _b64[_self.Bh[bi].H % 64];
/* No need to bother with FUZZY_FLAG_ELIMSEQ, because this
* digest has length 1. */
--remain;
}
/// <summary>Gets the hash of the specified data buffer.</summary>
/// <param name="data">Data buffer.</param>
/// <param name="len">Length of the data buffer to hash.</param>
/// <param name="hash">null</param>
/// <returns>Base64 representation of SpamSum $blocksize:$hash:$hash</returns>
public static string Data(byte[] data, uint len, out byte[] hash)
{
var fuzzyContext = new SpamSumContext();
result[resultOff] = 0;
}
fuzzyContext.Update(data, len);
/// <summary>Gets the hash of a file</summary>
/// <param name="filename">File path.</param>
public static byte[] File(string filename) =>
throw new NotImplementedException("SpamSum does not have a binary representation.");
hash = null;
/// <summary>Gets the hash of a file in hexadecimal and as a byte array.</summary>
/// <param name="filename">File path.</param>
/// <param name="hash">Byte array of the hash value.</param>
public static string File(string filename, out byte[] hash) =>
throw new NotImplementedException("Not yet implemented.");
return fuzzyContext.End();
}
/// <summary>Gets the hash of the specified data buffer.</summary>
/// <param name="data">Data buffer.</param>
/// <param name="len">Length of the data buffer to hash.</param>
/// <param name="hash">null</param>
/// <returns>Base64 representation of SpamSum $blocksize:$hash:$hash</returns>
public static string Data(byte[] data, uint len, out byte[] hash)
{
var fuzzyContext = new SpamSumContext();
/// <summary>Gets the hash of the specified data buffer.</summary>
/// <param name="data">Data buffer.</param>
/// <param name="hash">null</param>
/// <returns>Base64 representation of SpamSum $blocksize:$hash:$hash</returns>
public static string Data(byte[] data, out byte[] hash) => Data(data, (uint)data.Length, out hash);
fuzzyContext.Update(data, len);
// Converts an ASCII null-terminated string to .NET string
[MethodImpl(MethodImplOptions.AggressiveInlining)]
static string CToString(byte[] cString)
{
int count = 0;
hash = null;
// ReSharper disable once LoopCanBeConvertedToQuery
// LINQ is six times slower
foreach(byte c in cString)
{
if(c == 0)
break;
return fuzzyContext.End();
}
count++;
}
/// <summary>Gets the hash of the specified data buffer.</summary>
/// <param name="data">Data buffer.</param>
/// <param name="hash">null</param>
/// <returns>Base64 representation of SpamSum $blocksize:$hash:$hash</returns>
public static string Data(byte[] data, out byte[] hash) => Data(data, (uint)data.Length, out hash);
return Encoding.ASCII.GetString(cString, 0, count);
}
// Converts an ASCII null-terminated string to .NET string
[MethodImpl(MethodImplOptions.AggressiveInlining)]
static string CToString(byte[] cString)
{
var count = 0;
struct RollState
{
public byte[] Window;
// ReSharper disable once LoopCanBeConvertedToQuery
// LINQ is six times slower
foreach(byte c in cString)
{
if(c == 0)
break;
// ROLLING_WINDOW
public uint H1;
public uint H2;
public uint H3;
public uint N;
}
count++;
}
/* A blockhash contains a signature state for a specific (implicit) blocksize.
* The blocksize is given by SSDEEP_BS(index). The h and halfh members are the
* FNV hashes, where halfh stops to be reset after digest is SPAMSUM_LENGTH/2
* long. The halfh hash is needed be able to truncate digest for the second
* output hash to stay compatible with ssdeep output. */
struct BlockhashContext
{
public uint H;
public uint Halfh;
public byte[] Digest;
return Encoding.ASCII.GetString(cString, 0, count);
}
// SPAMSUM_LENGTH
public byte Halfdigest;
public uint Dlen;
}
struct RollState
{
public byte[] Window;
struct FuzzyState
{
public uint Bhstart;
public uint Bhend;
public BlockhashContext[] Bh;
// ROLLING_WINDOW
public uint H1;
public uint H2;
public uint H3;
public uint N;
}
//NUM_BLOCKHASHES
public ulong TotalSize;
public RollState Roll;
}
}
/* A blockhash contains a signature state for a specific (implicit) blocksize.
* The blocksize is given by SSDEEP_BS(index). The h and halfh members are the
* FNV hashes, where halfh stops to be reset after digest is SPAMSUM_LENGTH/2
* long. The halfh hash is needed be able to truncate digest for the second
* output hash to stay compatible with ssdeep output. */
struct BlockhashContext
{
public uint H;
public uint Halfh;
public byte[] Digest;
// SPAMSUM_LENGTH
public byte Halfdigest;
public uint Dlen;
}
struct FuzzyState
{
public uint Bhstart;
public uint Bhend;
public BlockhashContext[] Bh;
//NUM_BLOCKHASHES
public ulong TotalSize;
public RollState Roll;
}
}