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LZ4Codec.Unsafe64HC.Dirty.cs
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#region LZ4 original
/*
LZ4 - Fast LZ compression algorithm
Copyright (C) 2011-2012, Yann Collet.
BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:
* Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above
copyright notice, this list of conditions and the following disclaimer
in the documentation and/or other materials provided with the
distribution.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
You can contact the author at :
- LZ4 homepage : http://fastcompression.blogspot.com/p/lz4.html
- LZ4 source repository : http://code.google.com/p/lz4/
*/
#endregion
#region LZ4 port
/*
Copyright (c) 2013, Milosz Krajewski
All rights reserved.
Redistribution and use in source and binary forms, with or without modification, are permitted provided
that the following conditions are met:
* Redistributions of source code must retain the above copyright notice, this list of conditions
and the following disclaimer.
* Redistributions in binary form must reproduce the above copyright notice, this list of conditions
and the following disclaimer in the documentation and/or other materials provided with the distribution.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED
WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#endregion
// ReSharper disable InconsistentNaming
namespace LZ4PCL
{
#if INCLUDE_UNSAFE
public static partial class LZ4Codec
{
// Update chains up to ip (excluded)
private static unsafe void LZ4HC_Insert_64(LZ4HC_Data_Structure hc4, byte* src_p)
{
fixed (ushort* chainTable = hc4.chainTable) {
fixed (int* hashTable = hc4.hashTable) {
byte* src_base = hc4.src_base;
while (hc4.nextToUpdate < src_p) {
byte* p = hc4.nextToUpdate;
var delta =
(int) ((p) - (hashTable[((((*(uint*) (p))) * 2654435761u) >> HASHHC_ADJUST)] + src_base));
if (delta > MAX_DISTANCE) {
delta = MAX_DISTANCE;
}
chainTable[((int) p) & MAXD_MASK] = (ushort) delta;
hashTable[((((*(uint*) (p))) * 2654435761u) >> HASHHC_ADJUST)] = (int) (p - src_base);
hc4.nextToUpdate++;
}
}
}
}
private static unsafe int LZ4HC_CommonLength_64(byte* p1, byte* p2, byte* src_LASTLITERALS)
{
fixed (int* debruijn64 = DEBRUIJN_TABLE_64) {
byte* p1t = p1;
while (p1t < src_LASTLITERALS - (STEPSIZE_64 - 1)) {
long diff = (*(long*) (p2)) ^ (*(long*) (p1t));
if (diff == 0) {
p1t += STEPSIZE_64;
p2 += STEPSIZE_64;
continue;
}
p1t += debruijn64[(((ulong) ((diff) & -(diff)) * 0x0218A392CDABBD3FL)) >> 58];
return (int) (p1t - p1);
}
if ((p1t < (src_LASTLITERALS - 3)) && ((*(uint*) (p2)) == (*(uint*) (p1t)))) {
p1t += 4;
p2 += 4;
}
if ((p1t < (src_LASTLITERALS - 1)) && ((*(ushort*) (p2)) == (*(ushort*) (p1t)))) {
p1t += 2;
p2 += 2;
}
if ((p1t < src_LASTLITERALS) && (*p2 == *p1t)) {
p1t++;
}
return (int) (p1t - p1);
}
}
private static unsafe int LZ4HC_InsertAndFindBestMatch_64(
LZ4HC_Data_Structure hc4, byte* src_p, byte* src_LASTLITERALS, ref byte* matchpos)
{
fixed (ushort* chainTable = hc4.chainTable) {
fixed (int* hashTable = hc4.hashTable) {
byte* src_base = hc4.src_base;
int nbAttempts = MAX_NB_ATTEMPTS;
int repl = 0, ml = 0;
ushort delta = 0;
// HC4 match finder
LZ4HC_Insert_64(hc4, src_p);
byte* src_ref = (hashTable[((((*(uint*) (src_p))) * 2654435761u) >> HASHHC_ADJUST)] + src_base);
// Detect repetitive sequences of length <= 4
if (src_ref >= src_p - 4) // potential repetition
{
if ((*(uint*) (src_ref)) == (*(uint*) (src_p))) // confirmed
{
delta = (ushort) (src_p - src_ref);
repl =
ml =
LZ4HC_CommonLength_64(src_p + MINMATCH, src_ref + MINMATCH, src_LASTLITERALS) +
MINMATCH;
matchpos = src_ref;
}
src_ref = ((src_ref) - chainTable[((int) src_ref) & MAXD_MASK]);
}
while ((src_ref >= src_p - MAX_DISTANCE) && (nbAttempts != 0)) {
nbAttempts--;
if (*(src_ref + ml) == *(src_p + ml)) {
if ((*(uint*) (src_ref)) == (*(uint*) (src_p))) {
int mlt =
LZ4HC_CommonLength_64(src_p + MINMATCH, src_ref + MINMATCH, src_LASTLITERALS) +
MINMATCH;
if (mlt > ml) {
ml = mlt;
matchpos = src_ref;
}
}
}
src_ref = ((src_ref) - chainTable[((int) src_ref) & MAXD_MASK]);
}
// Complete table
if (repl != 0) {
byte* ptr = src_p;
byte* end = src_p + repl - (MINMATCH - 1);
while (ptr < end - delta) {
chainTable[((int) ptr) & MAXD_MASK] = delta; // Pre-Load
ptr++;
}
do {
chainTable[((int) ptr) & MAXD_MASK] = delta;
hashTable[((((*(uint*) (ptr))) * 2654435761u) >> HASHHC_ADJUST)] = (int) (ptr - src_base);
// Head of chain
ptr++;
} while (ptr < end);
hc4.nextToUpdate = end;
}
return ml;
}
}
}
private static unsafe int LZ4HC_InsertAndGetWiderMatch_64(
LZ4HC_Data_Structure hc4, byte* src_p, byte* startLimit, byte* src_LASTLITERALS, int longest,
ref byte* matchpos, ref byte* startpos)
{
fixed (ushort* chainTable = hc4.chainTable) {
fixed (int* hashTable = hc4.hashTable) {
fixed (int* debruijn64 = DEBRUIJN_TABLE_64) {
byte* src_base = hc4.src_base;
int nbAttempts = MAX_NB_ATTEMPTS;
var delta = (int) (src_p - startLimit);
// First Match
LZ4HC_Insert_64(hc4, src_p);
byte* src_ref = (hashTable[((((*(uint*) (src_p))) * 2654435761u) >> HASHHC_ADJUST)] + src_base);
while ((src_ref >= src_p - MAX_DISTANCE) && (nbAttempts != 0)) {
nbAttempts--;
if (*(startLimit + longest) == *(src_ref - delta + longest)) {
if ((*(uint*) (src_ref)) == (*(uint*) (src_p))) {
byte* reft = src_ref + MINMATCH;
byte* ipt = src_p + MINMATCH;
byte* startt = src_p;
while (ipt < src_LASTLITERALS - (STEPSIZE_64 - 1)) {
long diff = (*(long*) (reft)) ^ (*(long*) (ipt));
if (diff == 0) {
ipt += STEPSIZE_64;
reft += STEPSIZE_64;
continue;
}
ipt += debruijn64[(((ulong) ((diff) & -(diff)) * 0x0218A392CDABBD3FL)) >> 58];
goto _endCount;
}
if ((ipt < (src_LASTLITERALS - 3)) && ((*(uint*) (reft)) == (*(uint*) (ipt)))) {
ipt += 4;
reft += 4;
}
if ((ipt < (src_LASTLITERALS - 1)) && ((*(ushort*) (reft)) == (*(ushort*) (ipt)))) {
ipt += 2;
reft += 2;
}
if ((ipt < src_LASTLITERALS) && (*reft == *ipt)) {
ipt++;
}
_endCount:
reft = src_ref;
while ((startt > startLimit) && (reft > hc4.src_base) && (startt[-1] == reft[-1])) {
startt--;
reft--;
}
if ((ipt - startt) > longest) {
longest = (int) (ipt - startt);
matchpos = reft;
startpos = startt;
}
}
}
src_ref = ((src_ref) - chainTable[((int) src_ref) & MAXD_MASK]);
}
return longest;
}
}
}
}
private static unsafe int LZ4_encodeSequence_64(
ref byte* src_p, ref byte* dst_p, ref byte* src_anchor, int matchLength, byte* src_ref, byte* dst_end)
{
int len;
byte* dst_token = (dst_p)++;
// Encode Literal length
var length = (int) (src_p - src_anchor);
if ((dst_p + length + (2 + 1 + LASTLITERALS) + (length >> 8)) > dst_end) {
return 1; // Check output limit
}
if (length >= RUN_MASK) {
*dst_token = (RUN_MASK << ML_BITS);
len = length - RUN_MASK;
for (; len > 254; len -= 255) {
*(dst_p)++ = 255;
}
*(dst_p)++ = (byte) len;
} else {
*dst_token = (byte) (length << ML_BITS);
}
// Copy Literals
byte* _p = dst_p + (length);
do {
*(ulong*) dst_p = *(ulong*) src_anchor;
dst_p += 8;
src_anchor += 8;
} while (dst_p < _p);
dst_p = _p;
// Encode Offset
*(ushort*) dst_p = (ushort) (src_p - src_ref);
dst_p += 2;
// Encode MatchLength
len = (matchLength - MINMATCH);
if (dst_p + (1 + LASTLITERALS) + (length >> 8) > dst_end) {
return 1; // Check output limit
}
if (len >= ML_MASK) {
*dst_token += ML_MASK;
len -= ML_MASK;
for (; len > 509; len -= 510) {
*(dst_p)++ = 255;
*(dst_p)++ = 255;
}
if (len > 254) {
len -= 255;
*(dst_p)++ = 255;
}
*(dst_p)++ = (byte) len;
} else {
*dst_token += (byte) len;
}
// Prepare next loop
src_p += matchLength;
src_anchor = src_p;
return 0;
}
private static unsafe int LZ4_compressHCCtx_64(
LZ4HC_Data_Structure ctx,
byte* src,
byte* dst,
int src_len,
int dst_maxlen)
{
byte* src_p = src;
byte* src_anchor = src_p;
byte* src_end = src_p + src_len;
byte* src_mflimit = src_end - MFLIMIT;
byte* src_LASTLITERALS = (src_end - LASTLITERALS);
byte* dst_p = dst;
byte* dst_end = dst_p + dst_maxlen;
byte* src_ref = null;
byte* start2 = null;
byte* ref2 = null;
byte* start3 = null;
byte* ref3 = null;
src_p++;
// Main Loop
while (src_p < src_mflimit) {
int ml = LZ4HC_InsertAndFindBestMatch_64(ctx, src_p, src_LASTLITERALS, ref src_ref);
if (ml == 0) {
src_p++;
continue;
}
// saved, in case we would skip too much
byte* start0 = src_p;
byte* ref0 = src_ref;
int ml0 = ml;
_Search2:
int ml2 = src_p + ml < src_mflimit
? LZ4HC_InsertAndGetWiderMatch_64(ctx, src_p + ml - 2, src_p + 1, src_LASTLITERALS, ml, ref ref2,
ref start2)
: ml;
if (ml2 == ml) // No better match
{
if (LZ4_encodeSequence_64(ref src_p, ref dst_p, ref src_anchor, ml, src_ref, dst_end) != 0) {
return 0;
}
continue;
}
if (start0 < src_p && start2 < src_p + ml0) {
src_p = start0;
src_ref = ref0;
ml = ml0;
}
// Here, start0==ip
if ((start2 - src_p) < 3) // First Match too small : removed
{
ml = ml2;
src_p = start2;
src_ref = ref2;
goto _Search2;
}
_Search3:
// Currently we have :
// ml2 > ml1, and
// ip1+3 <= ip2 (usually < ip1+ml1)
if ((start2 - src_p) < OPTIMAL_ML) {
int new_ml = ml;
if (new_ml > OPTIMAL_ML) {
new_ml = OPTIMAL_ML;
}
if (src_p + new_ml > start2 + ml2 - MINMATCH) {
new_ml = (int) (start2 - src_p) + ml2 - MINMATCH;
}
int correction = new_ml - (int) (start2 - src_p);
if (correction > 0) {
start2 += correction;
ref2 += correction;
ml2 -= correction;
}
}
// Now, we have start2 = ip+new_ml, with new_ml=min(ml, OPTIMAL_ML=18)
int ml3 = start2 + ml2 < src_mflimit
? LZ4HC_InsertAndGetWiderMatch_64(ctx, start2 + ml2 - 3, start2, src_LASTLITERALS, ml2, ref ref3,
ref start3)
: ml2;
if (ml3 == ml2) // No better match : 2 sequences to encode
{
// ip & ref are known; Now for ml
if (start2 < src_p + ml) {
ml = (int) (start2 - src_p);
}
// Now, encode 2 sequences
if (LZ4_encodeSequence_64(ref src_p, ref dst_p, ref src_anchor, ml, src_ref, dst_end) != 0) {
return 0;
}
src_p = start2;
if (LZ4_encodeSequence_64(ref src_p, ref dst_p, ref src_anchor, ml2, ref2, dst_end) != 0) {
return 0;
}
continue;
}
if (start3 < src_p + ml + 3) // Not enough space for match 2 : remove it
{
if (start3 >= src_p + ml) // can write Seq1 immediately ==> Seq2 is removed, so Seq3 becomes Seq1
{
if (start2 < src_p + ml) {
var correction = (int) (src_p + ml - start2);
start2 += correction;
ref2 += correction;
ml2 -= correction;
if (ml2 < MINMATCH) {
start2 = start3;
ref2 = ref3;
ml2 = ml3;
}
}
if (LZ4_encodeSequence_64(ref src_p, ref dst_p, ref src_anchor, ml, src_ref, dst_end) != 0) {
return 0;
}
src_p = start3;
src_ref = ref3;
ml = ml3;
start0 = start2;
ref0 = ref2;
ml0 = ml2;
goto _Search2;
}
start2 = start3;
ref2 = ref3;
ml2 = ml3;
goto _Search3;
}
// OK, now we have 3 ascending matches; let's write at least the first one
// ip & ref are known; Now for ml
if (start2 < src_p + ml) {
if (start2 - src_p < ML_MASK) {
if (ml > OPTIMAL_ML) {
ml = OPTIMAL_ML;
}
if (src_p + ml > start2 + ml2 - MINMATCH) {
ml = (int) (start2 - src_p) + ml2 - MINMATCH;
}
int correction = ml - (int) (start2 - src_p);
if (correction > 0) {
start2 += correction;
ref2 += correction;
ml2 -= correction;
}
} else {
ml = (int) (start2 - src_p);
}
}
if (LZ4_encodeSequence_64(ref src_p, ref dst_p, ref src_anchor, ml, src_ref, dst_end) != 0) {
return 0;
}
src_p = start2;
src_ref = ref2;
ml = ml2;
start2 = start3;
ref2 = ref3;
ml2 = ml3;
goto _Search3;
}
// Encode Last Literals
var lastRun = (int) (src_end - src_anchor);
if ((dst_p - dst) + lastRun + 1 + ((lastRun + 255 - RUN_MASK) / 255) > (uint) dst_maxlen) {
return 0; // Check output limit
}
if (lastRun >= RUN_MASK) {
*dst_p++ = (RUN_MASK << ML_BITS);
lastRun -= RUN_MASK;
for (; lastRun > 254; lastRun -= 255) {
*dst_p++ = 255;
}
*dst_p++ = (byte) lastRun;
} else {
*dst_p++ = (byte) (lastRun << ML_BITS);
}
BlockCopy(src_anchor, dst_p, (int) (src_end - src_anchor));
dst_p += src_end - src_anchor;
// End
return (int) ((dst_p) - dst);
}
}
#endif
}
// ReSharper restore InconsistentNaming