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diff --git a/lib/zstd/bitstream.h b/lib/zstd/bitstream.h
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+/*
+ * 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);
+ /* 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;
+ 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 */
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