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Diffstat (limited to 'lib/zstd/bitstream.h')
| -rw-r--r-- | lib/zstd/bitstream.h | 380 |
1 files changed, 0 insertions, 380 deletions
diff --git a/lib/zstd/bitstream.h b/lib/zstd/bitstream.h deleted file mode 100644 index 5d6343c1a909..000000000000 --- a/lib/zstd/bitstream.h +++ /dev/null @@ -1,380 +0,0 @@ -/* - * bitstream - * Part of FSE library - * header file (to include) - * Copyright (C) 2013-2016, 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 - */ -#ifndef BITSTREAM_H_MODULE -#define BITSTREAM_H_MODULE - -/* -* This API consists of small unitary functions, which must be inlined for best performance. -* Since link-time-optimization is not available for all compilers, -* these functions are defined into a .h to be included. -*/ - -/*-**************************************** -* Dependencies -******************************************/ -#include "error_private.h" /* error codes and messages */ -#include "mem.h" /* unaligned access routines */ - -/*========================================= -* Target specific -=========================================*/ -#define STREAM_ACCUMULATOR_MIN_32 25 -#define STREAM_ACCUMULATOR_MIN_64 57 -#define STREAM_ACCUMULATOR_MIN ((U32)(ZSTD_32bits() ? STREAM_ACCUMULATOR_MIN_32 : STREAM_ACCUMULATOR_MIN_64)) - -/*-****************************************** -* bitStream encoding API (write forward) -********************************************/ -/* bitStream can mix input from multiple sources. -* A critical property of these streams is that they encode and decode in **reverse** direction. -* So the first bit sequence you add will be the last to be read, like a LIFO stack. -*/ -typedef struct { - size_t bitContainer; - int bitPos; - char *startPtr; - char *ptr; - char *endPtr; -} BIT_CStream_t; - -ZSTD_STATIC size_t BIT_initCStream(BIT_CStream_t *bitC, void *dstBuffer, size_t dstCapacity); -ZSTD_STATIC void BIT_addBits(BIT_CStream_t *bitC, size_t value, unsigned nbBits); -ZSTD_STATIC void BIT_flushBits(BIT_CStream_t *bitC); -ZSTD_STATIC size_t BIT_closeCStream(BIT_CStream_t *bitC); - -/* Start with initCStream, providing the size of buffer to write into. -* bitStream will never write outside of this buffer. -* `dstCapacity` must be >= sizeof(bitD->bitContainer), otherwise @return will be an error code. -* -* bits are first added to a local register. -* Local register is size_t, hence 64-bits on 64-bits systems, or 32-bits on 32-bits systems. -* Writing data into memory is an explicit operation, performed by the flushBits function. -* Hence keep track how many bits are potentially stored into local register to avoid register overflow. -* After a flushBits, a maximum of 7 bits might still be stored into local register. -* -* Avoid storing elements of more than 24 bits if you want compatibility with 32-bits bitstream readers. -* -* Last operation is to close the bitStream. -* The function returns the final size of CStream in bytes. -* If data couldn't fit into `dstBuffer`, it will return a 0 ( == not storable) -*/ - -/*-******************************************** -* bitStream decoding API (read backward) -**********************************************/ -typedef struct { - size_t bitContainer; - unsigned bitsConsumed; - const char *ptr; - const char *start; -} BIT_DStream_t; - -typedef enum { - BIT_DStream_unfinished = 0, - BIT_DStream_endOfBuffer = 1, - BIT_DStream_completed = 2, - BIT_DStream_overflow = 3 -} BIT_DStream_status; /* result of BIT_reloadDStream() */ -/* 1,2,4,8 would be better for bitmap combinations, but slows down performance a bit ... :( */ - -ZSTD_STATIC size_t BIT_initDStream(BIT_DStream_t *bitD, const void *srcBuffer, size_t srcSize); -ZSTD_STATIC size_t BIT_readBits(BIT_DStream_t *bitD, unsigned nbBits); -ZSTD_STATIC BIT_DStream_status BIT_reloadDStream(BIT_DStream_t *bitD); -ZSTD_STATIC unsigned BIT_endOfDStream(const BIT_DStream_t *bitD); - -/* Start by invoking BIT_initDStream(). -* A chunk of the bitStream is then stored into a local register. -* Local register size is 64-bits on 64-bits systems, 32-bits on 32-bits systems (size_t). -* You can then retrieve bitFields stored into the local register, **in reverse order**. -* Local register is explicitly reloaded from memory by the BIT_reloadDStream() method. -* A reload guarantee a minimum of ((8*sizeof(bitD->bitContainer))-7) bits when its result is BIT_DStream_unfinished. -* Otherwise, it can be less than that, so proceed accordingly. -* Checking if DStream has reached its end can be performed with BIT_endOfDStream(). -*/ - -/*-**************************************** -* unsafe API -******************************************/ -ZSTD_STATIC void BIT_addBitsFast(BIT_CStream_t *bitC, size_t value, unsigned nbBits); -/* faster, but works only if value is "clean", meaning all high bits above nbBits are 0 */ - -ZSTD_STATIC void BIT_flushBitsFast(BIT_CStream_t *bitC); -/* unsafe version; does not check buffer overflow */ - -ZSTD_STATIC size_t BIT_readBitsFast(BIT_DStream_t *bitD, unsigned nbBits); -/* faster, but works only if nbBits >= 1 */ - -/*-************************************************************** -* Internal functions -****************************************************************/ -ZSTD_STATIC unsigned BIT_highbit32(register U32 val) { return 31 - __builtin_clz(val); } - -/*===== Local Constants =====*/ -static const unsigned BIT_mask[] = {0, 1, 3, 7, 0xF, 0x1F, 0x3F, 0x7F, 0xFF, - 0x1FF, 0x3FF, 0x7FF, 0xFFF, 0x1FFF, 0x3FFF, 0x7FFF, 0xFFFF, 0x1FFFF, - 0x3FFFF, 0x7FFFF, 0xFFFFF, 0x1FFFFF, 0x3FFFFF, 0x7FFFFF, 0xFFFFFF, 0x1FFFFFF, 0x3FFFFFF}; /* up to 26 bits */ - -/*-************************************************************** -* bitStream encoding -****************************************************************/ -/*! BIT_initCStream() : - * `dstCapacity` must be > sizeof(void*) - * @return : 0 if success, - otherwise an error code (can be tested using ERR_isError() ) */ -ZSTD_STATIC size_t BIT_initCStream(BIT_CStream_t *bitC, void *startPtr, size_t dstCapacity) -{ - bitC->bitContainer = 0; - bitC->bitPos = 0; - bitC->startPtr = (char *)startPtr; - bitC->ptr = bitC->startPtr; - bitC->endPtr = bitC->startPtr + dstCapacity - sizeof(bitC->ptr); - if (dstCapacity <= sizeof(bitC->ptr)) - return ERROR(dstSize_tooSmall); - return 0; -} - -/*! BIT_addBits() : - can add up to 26 bits into `bitC`. - Does not check for register overflow ! */ -ZSTD_STATIC void BIT_addBits(BIT_CStream_t *bitC, size_t value, unsigned nbBits) -{ - bitC->bitContainer |= (value & BIT_mask[nbBits]) << bitC->bitPos; - bitC->bitPos += nbBits; -} - -/*! BIT_addBitsFast() : - * works only if `value` is _clean_, meaning all high bits above nbBits are 0 */ -ZSTD_STATIC void BIT_addBitsFast(BIT_CStream_t *bitC, size_t value, unsigned nbBits) -{ - bitC->bitContainer |= value << bitC->bitPos; - bitC->bitPos += nbBits; -} - -/*! BIT_flushBitsFast() : - * unsafe version; does not check buffer overflow */ -ZSTD_STATIC void BIT_flushBitsFast(BIT_CStream_t *bitC) -{ - size_t const nbBytes = bitC->bitPos >> 3; - ZSTD_writeLEST(bitC->ptr, bitC->bitContainer); - bitC->ptr += nbBytes; - bitC->bitPos &= 7; - bitC->bitContainer >>= nbBytes * 8; /* if bitPos >= sizeof(bitContainer)*8 --> undefined behavior */ -} - -/*! BIT_flushBits() : - * safe version; check for buffer overflow, and prevents it. - * note : does not signal buffer overflow. This will be revealed later on using BIT_closeCStream() */ -ZSTD_STATIC void BIT_flushBits(BIT_CStream_t *bitC) -{ - size_t const nbBytes = bitC->bitPos >> 3; - ZSTD_writeLEST(bitC->ptr, bitC->bitContainer); - bitC->ptr += nbBytes; - if (bitC->ptr > bitC->endPtr) - bitC->ptr = bitC->endPtr; - bitC->bitPos &= 7; - bitC->bitContainer >>= nbBytes * 8; /* if bitPos >= sizeof(bitContainer)*8 --> undefined behavior */ -} - -/*! BIT_closeCStream() : - * @return : size of CStream, in bytes, - or 0 if it could not fit into dstBuffer */ -ZSTD_STATIC size_t BIT_closeCStream(BIT_CStream_t *bitC) -{ - BIT_addBitsFast(bitC, 1, 1); /* endMark */ - BIT_flushBits(bitC); - - if (bitC->ptr >= bitC->endPtr) - return 0; /* doesn't fit within authorized budget : cancel */ - - return (bitC->ptr - bitC->startPtr) + (bitC->bitPos > 0); -} - -/*-******************************************************** -* bitStream decoding -**********************************************************/ -/*! BIT_initDStream() : -* Initialize a BIT_DStream_t. -* `bitD` : a pointer to an already allocated BIT_DStream_t structure. -* `srcSize` must be the *exact* size of the bitStream, in bytes. -* @return : size of stream (== srcSize) or an errorCode if a problem is detected -*/ -ZSTD_STATIC size_t BIT_initDStream(BIT_DStream_t *bitD, const void *srcBuffer, size_t srcSize) -{ - if (srcSize < 1) { - memset(bitD, 0, sizeof(*bitD)); - return ERROR(srcSize_wrong); - } - - if (srcSize >= sizeof(bitD->bitContainer)) { /* normal case */ - bitD->start = (const char *)srcBuffer; - bitD->ptr = (const char *)srcBuffer + srcSize - sizeof(bitD->bitContainer); - bitD->bitContainer = ZSTD_readLEST(bitD->ptr); - { - BYTE const lastByte = ((const BYTE *)srcBuffer)[srcSize - 1]; - bitD->bitsConsumed = lastByte ? 8 - BIT_highbit32(lastByte) : 0; /* ensures bitsConsumed is always set */ - if (lastByte == 0) - return ERROR(GENERIC); /* endMark not present */ - } - } else { - bitD->start = (const char *)srcBuffer; - bitD->ptr = bitD->start; - bitD->bitContainer = *(const BYTE *)(bitD->start); - switch (srcSize) { - case 7: bitD->bitContainer += (size_t)(((const BYTE *)(srcBuffer))[6]) << (sizeof(bitD->bitContainer) * 8 - 16); - fallthrough; - case 6: bitD->bitContainer += (size_t)(((const BYTE *)(srcBuffer))[5]) << (sizeof(bitD->bitContainer) * 8 - 24); - fallthrough; - case 5: bitD->bitContainer += (size_t)(((const BYTE *)(srcBuffer))[4]) << (sizeof(bitD->bitContainer) * 8 - 32); - fallthrough; - case 4: bitD->bitContainer += (size_t)(((const BYTE *)(srcBuffer))[3]) << 24; - fallthrough; - case 3: bitD->bitContainer += (size_t)(((const BYTE *)(srcBuffer))[2]) << 16; - fallthrough; - case 2: bitD->bitContainer += (size_t)(((const BYTE *)(srcBuffer))[1]) << 8; - fallthrough; - default:; - } - { - BYTE const lastByte = ((const BYTE *)srcBuffer)[srcSize - 1]; - bitD->bitsConsumed = lastByte ? 8 - BIT_highbit32(lastByte) : 0; - if (lastByte == 0) - return ERROR(GENERIC); /* endMark not present */ - } - bitD->bitsConsumed += (U32)(sizeof(bitD->bitContainer) - srcSize) * 8; - } - - return srcSize; -} - -ZSTD_STATIC size_t BIT_getUpperBits(size_t bitContainer, U32 const start) { return bitContainer >> start; } - -ZSTD_STATIC size_t BIT_getMiddleBits(size_t bitContainer, U32 const start, U32 const nbBits) { return (bitContainer >> start) & BIT_mask[nbBits]; } - -ZSTD_STATIC size_t BIT_getLowerBits(size_t bitContainer, U32 const nbBits) { return bitContainer & BIT_mask[nbBits]; } - -/*! BIT_lookBits() : - * Provides next n bits from local register. - * local register is not modified. - * On 32-bits, maxNbBits==24. - * On 64-bits, maxNbBits==56. - * @return : value extracted - */ -ZSTD_STATIC size_t BIT_lookBits(const BIT_DStream_t *bitD, U32 nbBits) -{ - U32 const bitMask = sizeof(bitD->bitContainer) * 8 - 1; - return ((bitD->bitContainer << (bitD->bitsConsumed & bitMask)) >> 1) >> ((bitMask - nbBits) & bitMask); -} - -/*! BIT_lookBitsFast() : -* unsafe version; only works only if nbBits >= 1 */ -ZSTD_STATIC size_t BIT_lookBitsFast(const BIT_DStream_t *bitD, U32 nbBits) -{ - U32 const bitMask = sizeof(bitD->bitContainer) * 8 - 1; - return (bitD->bitContainer << (bitD->bitsConsumed & bitMask)) >> (((bitMask + 1) - nbBits) & bitMask); -} - -ZSTD_STATIC void BIT_skipBits(BIT_DStream_t *bitD, U32 nbBits) { bitD->bitsConsumed += nbBits; } - -/*! BIT_readBits() : - * Read (consume) next n bits from local register and update. - * Pay attention to not read more than nbBits contained into local register. - * @return : extracted value. - */ -ZSTD_STATIC size_t BIT_readBits(BIT_DStream_t *bitD, U32 nbBits) -{ - size_t const value = BIT_lookBits(bitD, nbBits); - BIT_skipBits(bitD, nbBits); - return value; -} - -/*! BIT_readBitsFast() : -* unsafe version; only works only if nbBits >= 1 */ -ZSTD_STATIC size_t BIT_readBitsFast(BIT_DStream_t *bitD, U32 nbBits) -{ - size_t const value = BIT_lookBitsFast(bitD, nbBits); - BIT_skipBits(bitD, nbBits); - return value; -} - -/*! BIT_reloadDStream() : -* Refill `bitD` from buffer previously set in BIT_initDStream() . -* This function is safe, it guarantees it will not read beyond src buffer. -* @return : status of `BIT_DStream_t` internal register. - if status == BIT_DStream_unfinished, internal register is filled with >= (sizeof(bitD->bitContainer)*8 - 7) bits */ -ZSTD_STATIC BIT_DStream_status BIT_reloadDStream(BIT_DStream_t *bitD) -{ - if (bitD->bitsConsumed > (sizeof(bitD->bitContainer) * 8)) /* should not happen => corruption detected */ - return BIT_DStream_overflow; - - if (bitD->ptr >= bitD->start + sizeof(bitD->bitContainer)) { - bitD->ptr -= bitD->bitsConsumed >> 3; - bitD->bitsConsumed &= 7; - bitD->bitContainer = ZSTD_readLEST(bitD->ptr); - return BIT_DStream_unfinished; - } - if (bitD->ptr == bitD->start) { - if (bitD->bitsConsumed < sizeof(bitD->bitContainer) * 8) - return BIT_DStream_endOfBuffer; - return BIT_DStream_completed; - } - { - U32 nbBytes = bitD->bitsConsumed >> 3; - BIT_DStream_status result = BIT_DStream_unfinished; - if (bitD->ptr - nbBytes < bitD->start) { - nbBytes = (U32)(bitD->ptr - bitD->start); /* ptr > start */ - result = BIT_DStream_endOfBuffer; - } - bitD->ptr -= nbBytes; - bitD->bitsConsumed -= nbBytes * 8; - bitD->bitContainer = ZSTD_readLEST(bitD->ptr); /* reminder : srcSize > sizeof(bitD) */ - return result; - } -} - -/*! BIT_endOfDStream() : -* @return Tells if DStream has exactly reached its end (all bits consumed). -*/ -ZSTD_STATIC unsigned BIT_endOfDStream(const BIT_DStream_t *DStream) -{ - return ((DStream->ptr == DStream->start) && (DStream->bitsConsumed == sizeof(DStream->bitContainer) * 8)); -} - -#endif /* BITSTREAM_H_MODULE */ |