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diff --git a/vendor/github.com/DataDog/zstd/bitstream.h b/vendor/github.com/DataDog/zstd/bitstream.h
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-/* ******************************************************************
- bitstream
- Part of FSE library
- Copyright (C) 2013-present, 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 :
- - Source repository : https://github.com/Cyan4973/FiniteStateEntropy
-****************************************************************** */
-#ifndef BITSTREAM_H_MODULE
-#define BITSTREAM_H_MODULE
-
-#if defined (__cplusplus)
-extern "C" {
-#endif
-
-/*
-* 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 "mem.h" /* unaligned access routines */
-#include "debug.h" /* assert(), DEBUGLOG(), RAWLOG() */
-#include "error_private.h" /* error codes and messages */
-
-
-/*=========================================
-* Target specific
-=========================================*/
-#if defined(__BMI__) && defined(__GNUC__)
-# include <immintrin.h> /* support for bextr (experimental) */
-#endif
-
-#define STREAM_ACCUMULATOR_MIN_32 25
-#define STREAM_ACCUMULATOR_MIN_64 57
-#define STREAM_ACCUMULATOR_MIN ((U32)(MEM_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;
- unsigned bitPos;
- char* startPtr;
- char* ptr;
- char* endPtr;
-} BIT_CStream_t;
-
-MEM_STATIC size_t BIT_initCStream(BIT_CStream_t* bitC, void* dstBuffer, size_t dstCapacity);
-MEM_STATIC void BIT_addBits(BIT_CStream_t* bitC, size_t value, unsigned nbBits);
-MEM_STATIC void BIT_flushBits(BIT_CStream_t* bitC);
-MEM_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;
- const char* limitPtr;
-} 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 ... :( */
-
-MEM_STATIC size_t BIT_initDStream(BIT_DStream_t* bitD, const void* srcBuffer, size_t srcSize);
-MEM_STATIC size_t BIT_readBits(BIT_DStream_t* bitD, unsigned nbBits);
-MEM_STATIC BIT_DStream_status BIT_reloadDStream(BIT_DStream_t* bitD);
-MEM_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
-******************************************/
-MEM_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 */
-
-MEM_STATIC void BIT_flushBitsFast(BIT_CStream_t* bitC);
-/* unsafe version; does not check buffer overflow */
-
-MEM_STATIC size_t BIT_readBitsFast(BIT_DStream_t* bitD, unsigned nbBits);
-/* faster, but works only if nbBits >= 1 */
-
-
-
-/*-**************************************************************
-* Internal functions
-****************************************************************/
-MEM_STATIC unsigned BIT_highbit32 (U32 val)
-{
- assert(val != 0);
- {
-# if defined(_MSC_VER) /* Visual */
- unsigned long r=0;
- _BitScanReverse ( &r, val );
- return (unsigned) r;
-# elif defined(__GNUC__) && (__GNUC__ >= 3) /* Use GCC Intrinsic */
- return 31 - __builtin_clz (val);
-# else /* Software version */
- static const unsigned DeBruijnClz[32] = { 0, 9, 1, 10, 13, 21, 2, 29,
- 11, 14, 16, 18, 22, 25, 3, 30,
- 8, 12, 20, 28, 15, 17, 24, 7,
- 19, 27, 23, 6, 26, 5, 4, 31 };
- U32 v = val;
- v |= v >> 1;
- v |= v >> 2;
- v |= v >> 4;
- v |= v >> 8;
- v |= v >> 16;
- return DeBruijnClz[ (U32) (v * 0x07C4ACDDU) >> 27];
-# endif
- }
-}
-
-/*===== 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, 0x7FFFFFF, 0xFFFFFFF, 0x1FFFFFFF,
- 0x3FFFFFFF, 0x7FFFFFFF}; /* up to 31 bits */
-#define BIT_MASK_SIZE (sizeof(BIT_mask) / sizeof(BIT_mask[0]))
-
-/*-**************************************************************
-* bitStream encoding
-****************************************************************/
-/*! BIT_initCStream() :
- * `dstCapacity` must be > sizeof(size_t)
- * @return : 0 if success,
- * otherwise an error code (can be tested using ERR_isError()) */
-MEM_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->bitContainer);
- if (dstCapacity <= sizeof(bitC->bitContainer)) return ERROR(dstSize_tooSmall);
- return 0;
-}
-
-/*! BIT_addBits() :
- * can add up to 31 bits into `bitC`.
- * Note : does not check for register overflow ! */
-MEM_STATIC void BIT_addBits(BIT_CStream_t* bitC,
- size_t value, unsigned nbBits)
-{
- MEM_STATIC_ASSERT(BIT_MASK_SIZE == 32);
- assert(nbBits < BIT_MASK_SIZE);
- assert(nbBits + bitC->bitPos < sizeof(bitC->bitContainer) * 8);
- 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 */
-MEM_STATIC void BIT_addBitsFast(BIT_CStream_t* bitC,
- size_t value, unsigned nbBits)
-{
- assert((value>>nbBits) == 0);
- assert(nbBits + bitC->bitPos < sizeof(bitC->bitContainer) * 8);
- bitC->bitContainer |= value << bitC->bitPos;
- bitC->bitPos += nbBits;
-}
-
-/*! BIT_flushBitsFast() :
- * assumption : bitContainer has not overflowed
- * unsafe version; does not check buffer overflow */
-MEM_STATIC void BIT_flushBitsFast(BIT_CStream_t* bitC)
-{
- size_t const nbBytes = bitC->bitPos >> 3;
- assert(bitC->bitPos < sizeof(bitC->bitContainer) * 8);
- MEM_writeLEST(bitC->ptr, bitC->bitContainer);
- bitC->ptr += nbBytes;
- assert(bitC->ptr <= bitC->endPtr);
- bitC->bitPos &= 7;
- bitC->bitContainer >>= nbBytes*8;
-}
-
-/*! BIT_flushBits() :
- * assumption : bitContainer has not overflowed
- * safe version; check for buffer overflow, and prevents it.
- * note : does not signal buffer overflow.
- * overflow will be revealed later on using BIT_closeCStream() */
-MEM_STATIC void BIT_flushBits(BIT_CStream_t* bitC)
-{
- size_t const nbBytes = bitC->bitPos >> 3;
- assert(bitC->bitPos < sizeof(bitC->bitContainer) * 8);
- MEM_writeLEST(bitC->ptr, bitC->bitContainer);
- bitC->ptr += nbBytes;
- if (bitC->ptr > bitC->endPtr) bitC->ptr = bitC->endPtr;
- bitC->bitPos &= 7;
- bitC->bitContainer >>= nbBytes*8;
-}
-
-/*! BIT_closeCStream() :
- * @return : size of CStream, in bytes,
- * or 0 if it could not fit into dstBuffer */
-MEM_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; /* overflow detected */
- 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
- */
-MEM_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); }
-
- bitD->start = (const char*)srcBuffer;
- bitD->limitPtr = bitD->start + sizeof(bitD->bitContainer);
-
- if (srcSize >= sizeof(bitD->bitContainer)) { /* normal case */
- bitD->ptr = (const char*)srcBuffer + srcSize - sizeof(bitD->bitContainer);
- bitD->bitContainer = MEM_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->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);
- /* fall-through */
-
- case 6: bitD->bitContainer += (size_t)(((const BYTE*)(srcBuffer))[5]) << (sizeof(bitD->bitContainer)*8 - 24);
- /* fall-through */
-
- case 5: bitD->bitContainer += (size_t)(((const BYTE*)(srcBuffer))[4]) << (sizeof(bitD->bitContainer)*8 - 32);
- /* fall-through */
-
- case 4: bitD->bitContainer += (size_t)(((const BYTE*)(srcBuffer))[3]) << 24;
- /* fall-through */
-
- case 3: bitD->bitContainer += (size_t)(((const BYTE*)(srcBuffer))[2]) << 16;
- /* fall-through */
-
- case 2: bitD->bitContainer += (size_t)(((const BYTE*)(srcBuffer))[1]) << 8;
- /* fall-through */
-
- default: break;
- }
- { BYTE const lastByte = ((const BYTE*)srcBuffer)[srcSize-1];
- bitD->bitsConsumed = lastByte ? 8 - BIT_highbit32(lastByte) : 0;
- if (lastByte == 0) return ERROR(corruption_detected); /* endMark not present */
- }
- bitD->bitsConsumed += (U32)(sizeof(bitD->bitContainer) - srcSize)*8;
- }
-
- return srcSize;
-}
-
-MEM_STATIC size_t BIT_getUpperBits(size_t bitContainer, U32 const start)
-{
- return bitContainer >> start;
-}
-
-MEM_STATIC size_t BIT_getMiddleBits(size_t bitContainer, U32 const start, U32 const nbBits)
-{
- U32 const regMask = sizeof(bitContainer)*8 - 1;
- /* if start > regMask, bitstream is corrupted, and result is undefined */
- assert(nbBits < BIT_MASK_SIZE);
- return (bitContainer >> (start & regMask)) & BIT_mask[nbBits];
-}
-
-MEM_STATIC size_t BIT_getLowerBits(size_t bitContainer, U32 const nbBits)
-{
- assert(nbBits < BIT_MASK_SIZE);
- 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 */
-MEM_STATIC size_t BIT_lookBits(const BIT_DStream_t* bitD, U32 nbBits)
-{
- /* arbitrate between double-shift and shift+mask */
-#if 1
- /* if bitD->bitsConsumed + nbBits > sizeof(bitD->bitContainer)*8,
- * bitstream is likely corrupted, and result is undefined */
- return BIT_getMiddleBits(bitD->bitContainer, (sizeof(bitD->bitContainer)*8) - bitD->bitsConsumed - nbBits, nbBits);
-#else
- /* this code path is slower on my os-x laptop */
- U32 const regMask = sizeof(bitD->bitContainer)*8 - 1;
- return ((bitD->bitContainer << (bitD->bitsConsumed & regMask)) >> 1) >> ((regMask-nbBits) & regMask);
-#endif
-}
-
-/*! BIT_lookBitsFast() :
- * unsafe version; only works if nbBits >= 1 */
-MEM_STATIC size_t BIT_lookBitsFast(const BIT_DStream_t* bitD, U32 nbBits)
-{
- U32 const regMask = sizeof(bitD->bitContainer)*8 - 1;
- assert(nbBits >= 1);
- return (bitD->bitContainer << (bitD->bitsConsumed & regMask)) >> (((regMask+1)-nbBits) & regMask);
-}
-
-MEM_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. */
-MEM_STATIC size_t BIT_readBits(BIT_DStream_t* bitD, unsigned 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 */
-MEM_STATIC size_t BIT_readBitsFast(BIT_DStream_t* bitD, unsigned nbBits)
-{
- size_t const value = BIT_lookBitsFast(bitD, nbBits);
- assert(nbBits >= 1);
- 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.
- * when status == BIT_DStream_unfinished, internal register is filled with at least 25 or 57 bits */
-MEM_STATIC BIT_DStream_status BIT_reloadDStream(BIT_DStream_t* bitD)
-{
- if (bitD->bitsConsumed > (sizeof(bitD->bitContainer)*8)) /* overflow detected, like end of stream */
- return BIT_DStream_overflow;
-
- if (bitD->ptr >= bitD->limitPtr) {
- bitD->ptr -= bitD->bitsConsumed >> 3;
- bitD->bitsConsumed &= 7;
- bitD->bitContainer = MEM_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;
- }
- /* start < ptr < limitPtr */
- { 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 = MEM_readLEST(bitD->ptr); /* reminder : srcSize > sizeof(bitD->bitContainer), otherwise bitD->ptr == bitD->start */
- return result;
- }
-}
-
-/*! BIT_endOfDStream() :
- * @return : 1 if DStream has _exactly_ reached its end (all bits consumed).
- */
-MEM_STATIC unsigned BIT_endOfDStream(const BIT_DStream_t* DStream)
-{
- return ((DStream->ptr == DStream->start) && (DStream->bitsConsumed == sizeof(DStream->bitContainer)*8));
-}
-
-#if defined (__cplusplus)
-}
-#endif
-
-#endif /* BITSTREAM_H_MODULE */