forked from Minki/linux
244 lines
7.6 KiB
C
244 lines
7.6 KiB
C
|
/*
|
||
|
* Common functions of New Generation Entropy library
|
||
|
* Copyright (C) 2016, 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.
|
||
|
*
|
||
|
* This program is free software; you can redistribute it and/or modify it under
|
||
|
* the terms of the GNU General Public License version 2 as published by the
|
||
|
* Free Software Foundation. This program is dual-licensed; you may select
|
||
|
* either version 2 of the GNU General Public License ("GPL") or BSD license
|
||
|
* ("BSD").
|
||
|
*
|
||
|
* You can contact the author at :
|
||
|
* - Source repository : https://github.com/Cyan4973/FiniteStateEntropy
|
||
|
*/
|
||
|
|
||
|
/* *************************************
|
||
|
* Dependencies
|
||
|
***************************************/
|
||
|
#include "error_private.h" /* ERR_*, ERROR */
|
||
|
#include "fse.h"
|
||
|
#include "huf.h"
|
||
|
#include "mem.h"
|
||
|
|
||
|
/*=== Version ===*/
|
||
|
unsigned FSE_versionNumber(void) { return FSE_VERSION_NUMBER; }
|
||
|
|
||
|
/*=== Error Management ===*/
|
||
|
unsigned FSE_isError(size_t code) { return ERR_isError(code); }
|
||
|
|
||
|
unsigned HUF_isError(size_t code) { return ERR_isError(code); }
|
||
|
|
||
|
/*-**************************************************************
|
||
|
* FSE NCount encoding-decoding
|
||
|
****************************************************************/
|
||
|
size_t FSE_readNCount(short *normalizedCounter, unsigned *maxSVPtr, unsigned *tableLogPtr, const void *headerBuffer, size_t hbSize)
|
||
|
{
|
||
|
const BYTE *const istart = (const BYTE *)headerBuffer;
|
||
|
const BYTE *const iend = istart + hbSize;
|
||
|
const BYTE *ip = istart;
|
||
|
int nbBits;
|
||
|
int remaining;
|
||
|
int threshold;
|
||
|
U32 bitStream;
|
||
|
int bitCount;
|
||
|
unsigned charnum = 0;
|
||
|
int previous0 = 0;
|
||
|
|
||
|
if (hbSize < 4)
|
||
|
return ERROR(srcSize_wrong);
|
||
|
bitStream = ZSTD_readLE32(ip);
|
||
|
nbBits = (bitStream & 0xF) + FSE_MIN_TABLELOG; /* extract tableLog */
|
||
|
if (nbBits > FSE_TABLELOG_ABSOLUTE_MAX)
|
||
|
return ERROR(tableLog_tooLarge);
|
||
|
bitStream >>= 4;
|
||
|
bitCount = 4;
|
||
|
*tableLogPtr = nbBits;
|
||
|
remaining = (1 << nbBits) + 1;
|
||
|
threshold = 1 << nbBits;
|
||
|
nbBits++;
|
||
|
|
||
|
while ((remaining > 1) & (charnum <= *maxSVPtr)) {
|
||
|
if (previous0) {
|
||
|
unsigned n0 = charnum;
|
||
|
while ((bitStream & 0xFFFF) == 0xFFFF) {
|
||
|
n0 += 24;
|
||
|
if (ip < iend - 5) {
|
||
|
ip += 2;
|
||
|
bitStream = ZSTD_readLE32(ip) >> bitCount;
|
||
|
} else {
|
||
|
bitStream >>= 16;
|
||
|
bitCount += 16;
|
||
|
}
|
||
|
}
|
||
|
while ((bitStream & 3) == 3) {
|
||
|
n0 += 3;
|
||
|
bitStream >>= 2;
|
||
|
bitCount += 2;
|
||
|
}
|
||
|
n0 += bitStream & 3;
|
||
|
bitCount += 2;
|
||
|
if (n0 > *maxSVPtr)
|
||
|
return ERROR(maxSymbolValue_tooSmall);
|
||
|
while (charnum < n0)
|
||
|
normalizedCounter[charnum++] = 0;
|
||
|
if ((ip <= iend - 7) || (ip + (bitCount >> 3) <= iend - 4)) {
|
||
|
ip += bitCount >> 3;
|
||
|
bitCount &= 7;
|
||
|
bitStream = ZSTD_readLE32(ip) >> bitCount;
|
||
|
} else {
|
||
|
bitStream >>= 2;
|
||
|
}
|
||
|
}
|
||
|
{
|
||
|
int const max = (2 * threshold - 1) - remaining;
|
||
|
int count;
|
||
|
|
||
|
if ((bitStream & (threshold - 1)) < (U32)max) {
|
||
|
count = bitStream & (threshold - 1);
|
||
|
bitCount += nbBits - 1;
|
||
|
} else {
|
||
|
count = bitStream & (2 * threshold - 1);
|
||
|
if (count >= threshold)
|
||
|
count -= max;
|
||
|
bitCount += nbBits;
|
||
|
}
|
||
|
|
||
|
count--; /* extra accuracy */
|
||
|
remaining -= count < 0 ? -count : count; /* -1 means +1 */
|
||
|
normalizedCounter[charnum++] = (short)count;
|
||
|
previous0 = !count;
|
||
|
while (remaining < threshold) {
|
||
|
nbBits--;
|
||
|
threshold >>= 1;
|
||
|
}
|
||
|
|
||
|
if ((ip <= iend - 7) || (ip + (bitCount >> 3) <= iend - 4)) {
|
||
|
ip += bitCount >> 3;
|
||
|
bitCount &= 7;
|
||
|
} else {
|
||
|
bitCount -= (int)(8 * (iend - 4 - ip));
|
||
|
ip = iend - 4;
|
||
|
}
|
||
|
bitStream = ZSTD_readLE32(ip) >> (bitCount & 31);
|
||
|
}
|
||
|
} /* while ((remaining>1) & (charnum<=*maxSVPtr)) */
|
||
|
if (remaining != 1)
|
||
|
return ERROR(corruption_detected);
|
||
|
if (bitCount > 32)
|
||
|
return ERROR(corruption_detected);
|
||
|
*maxSVPtr = charnum - 1;
|
||
|
|
||
|
ip += (bitCount + 7) >> 3;
|
||
|
return ip - istart;
|
||
|
}
|
||
|
|
||
|
/*! HUF_readStats() :
|
||
|
Read compact Huffman tree, saved by HUF_writeCTable().
|
||
|
`huffWeight` is destination buffer.
|
||
|
`rankStats` is assumed to be a table of at least HUF_TABLELOG_MAX U32.
|
||
|
@return : size read from `src` , or an error Code .
|
||
|
Note : Needed by HUF_readCTable() and HUF_readDTableX?() .
|
||
|
*/
|
||
|
size_t HUF_readStats_wksp(BYTE *huffWeight, size_t hwSize, U32 *rankStats, U32 *nbSymbolsPtr, U32 *tableLogPtr, const void *src, size_t srcSize, void *workspace, size_t workspaceSize)
|
||
|
{
|
||
|
U32 weightTotal;
|
||
|
const BYTE *ip = (const BYTE *)src;
|
||
|
size_t iSize;
|
||
|
size_t oSize;
|
||
|
|
||
|
if (!srcSize)
|
||
|
return ERROR(srcSize_wrong);
|
||
|
iSize = ip[0];
|
||
|
/* memset(huffWeight, 0, hwSize); */ /* is not necessary, even though some analyzer complain ... */
|
||
|
|
||
|
if (iSize >= 128) { /* special header */
|
||
|
oSize = iSize - 127;
|
||
|
iSize = ((oSize + 1) / 2);
|
||
|
if (iSize + 1 > srcSize)
|
||
|
return ERROR(srcSize_wrong);
|
||
|
if (oSize >= hwSize)
|
||
|
return ERROR(corruption_detected);
|
||
|
ip += 1;
|
||
|
{
|
||
|
U32 n;
|
||
|
for (n = 0; n < oSize; n += 2) {
|
||
|
huffWeight[n] = ip[n / 2] >> 4;
|
||
|
huffWeight[n + 1] = ip[n / 2] & 15;
|
||
|
}
|
||
|
}
|
||
|
} else { /* header compressed with FSE (normal case) */
|
||
|
if (iSize + 1 > srcSize)
|
||
|
return ERROR(srcSize_wrong);
|
||
|
oSize = FSE_decompress_wksp(huffWeight, hwSize - 1, ip + 1, iSize, 6, workspace, workspaceSize); /* max (hwSize-1) values decoded, as last one is implied */
|
||
|
if (FSE_isError(oSize))
|
||
|
return oSize;
|
||
|
}
|
||
|
|
||
|
/* collect weight stats */
|
||
|
memset(rankStats, 0, (HUF_TABLELOG_MAX + 1) * sizeof(U32));
|
||
|
weightTotal = 0;
|
||
|
{
|
||
|
U32 n;
|
||
|
for (n = 0; n < oSize; n++) {
|
||
|
if (huffWeight[n] >= HUF_TABLELOG_MAX)
|
||
|
return ERROR(corruption_detected);
|
||
|
rankStats[huffWeight[n]]++;
|
||
|
weightTotal += (1 << huffWeight[n]) >> 1;
|
||
|
}
|
||
|
}
|
||
|
if (weightTotal == 0)
|
||
|
return ERROR(corruption_detected);
|
||
|
|
||
|
/* get last non-null symbol weight (implied, total must be 2^n) */
|
||
|
{
|
||
|
U32 const tableLog = BIT_highbit32(weightTotal) + 1;
|
||
|
if (tableLog > HUF_TABLELOG_MAX)
|
||
|
return ERROR(corruption_detected);
|
||
|
*tableLogPtr = tableLog;
|
||
|
/* determine last weight */
|
||
|
{
|
||
|
U32 const total = 1 << tableLog;
|
||
|
U32 const rest = total - weightTotal;
|
||
|
U32 const verif = 1 << BIT_highbit32(rest);
|
||
|
U32 const lastWeight = BIT_highbit32(rest) + 1;
|
||
|
if (verif != rest)
|
||
|
return ERROR(corruption_detected); /* last value must be a clean power of 2 */
|
||
|
huffWeight[oSize] = (BYTE)lastWeight;
|
||
|
rankStats[lastWeight]++;
|
||
|
}
|
||
|
}
|
||
|
|
||
|
/* check tree construction validity */
|
||
|
if ((rankStats[1] < 2) || (rankStats[1] & 1))
|
||
|
return ERROR(corruption_detected); /* by construction : at least 2 elts of rank 1, must be even */
|
||
|
|
||
|
/* results */
|
||
|
*nbSymbolsPtr = (U32)(oSize + 1);
|
||
|
return iSize + 1;
|
||
|
}
|