5414dd7978
* When dynamic dispatching to bmi2 add lzcnt and bmi to the TARGET_ATTRIBUTE. * Centralize the bmi2 TARGET_ATTRIBUTE definition to BMI2_TARGET_ATTRIBUTE so we can change it in the future. * Only enable bmi2 when both bmi1 & bmi2 are supported. There shouldn't be any cases where bmi2 is supported but bmi1 isn't. But, since we are using the instruction we should check bmi1 as well.
369 lines
14 KiB
C
369 lines
14 KiB
C
/* ******************************************************************
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* Common functions of New Generation Entropy library
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* Copyright (c) Yann Collet, Facebook, Inc.
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*
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* You can contact the author at :
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* - FSE+HUF source repository : https://github.com/Cyan4973/FiniteStateEntropy
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* - Public forum : https://groups.google.com/forum/#!forum/lz4c
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*
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* This source code is licensed under both the BSD-style license (found in the
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* LICENSE file in the root directory of this source tree) and the GPLv2 (found
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* in the COPYING file in the root directory of this source tree).
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* You may select, at your option, one of the above-listed licenses.
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****************************************************************** */
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/* *************************************
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* Dependencies
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***************************************/
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#include "mem.h"
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#include "error_private.h" /* ERR_*, ERROR */
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#define FSE_STATIC_LINKING_ONLY /* FSE_MIN_TABLELOG */
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#include "fse.h"
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#define HUF_STATIC_LINKING_ONLY /* HUF_TABLELOG_ABSOLUTEMAX */
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#include "huf.h"
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/*=== Version ===*/
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unsigned FSE_versionNumber(void) { return FSE_VERSION_NUMBER; }
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/*=== Error Management ===*/
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unsigned FSE_isError(size_t code) { return ERR_isError(code); }
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const char* FSE_getErrorName(size_t code) { return ERR_getErrorName(code); }
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unsigned HUF_isError(size_t code) { return ERR_isError(code); }
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const char* HUF_getErrorName(size_t code) { return ERR_getErrorName(code); }
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/*-**************************************************************
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* FSE NCount encoding-decoding
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****************************************************************/
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static U32 FSE_ctz(U32 val)
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{
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assert(val != 0);
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{
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# if defined(_MSC_VER) /* Visual */
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if (val != 0) {
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unsigned long r;
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_BitScanForward(&r, val);
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return (unsigned)r;
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} else {
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/* Should not reach this code path */
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__assume(0);
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}
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# elif defined(__GNUC__) && (__GNUC__ >= 3) /* GCC Intrinsic */
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return __builtin_ctz(val);
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# elif defined(__ICCARM__) /* IAR Intrinsic */
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return __CTZ(val);
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# else /* Software version */
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U32 count = 0;
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while ((val & 1) == 0) {
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val >>= 1;
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++count;
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}
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return count;
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# endif
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}
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}
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FORCE_INLINE_TEMPLATE
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size_t FSE_readNCount_body(short* normalizedCounter, unsigned* maxSVPtr, unsigned* tableLogPtr,
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const void* headerBuffer, size_t hbSize)
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{
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const BYTE* const istart = (const BYTE*) headerBuffer;
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const BYTE* const iend = istart + hbSize;
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const BYTE* ip = istart;
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int nbBits;
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int remaining;
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int threshold;
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U32 bitStream;
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int bitCount;
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unsigned charnum = 0;
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unsigned const maxSV1 = *maxSVPtr + 1;
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int previous0 = 0;
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if (hbSize < 8) {
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/* This function only works when hbSize >= 8 */
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char buffer[8] = {0};
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ZSTD_memcpy(buffer, headerBuffer, hbSize);
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{ size_t const countSize = FSE_readNCount(normalizedCounter, maxSVPtr, tableLogPtr,
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buffer, sizeof(buffer));
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if (FSE_isError(countSize)) return countSize;
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if (countSize > hbSize) return ERROR(corruption_detected);
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return countSize;
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} }
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assert(hbSize >= 8);
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/* init */
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ZSTD_memset(normalizedCounter, 0, (*maxSVPtr+1) * sizeof(normalizedCounter[0])); /* all symbols not present in NCount have a frequency of 0 */
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bitStream = MEM_readLE32(ip);
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nbBits = (bitStream & 0xF) + FSE_MIN_TABLELOG; /* extract tableLog */
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if (nbBits > FSE_TABLELOG_ABSOLUTE_MAX) return ERROR(tableLog_tooLarge);
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bitStream >>= 4;
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bitCount = 4;
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*tableLogPtr = nbBits;
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remaining = (1<<nbBits)+1;
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threshold = 1<<nbBits;
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nbBits++;
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for (;;) {
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if (previous0) {
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/* Count the number of repeats. Each time the
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* 2-bit repeat code is 0b11 there is another
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* repeat.
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* Avoid UB by setting the high bit to 1.
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*/
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int repeats = FSE_ctz(~bitStream | 0x80000000) >> 1;
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while (repeats >= 12) {
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charnum += 3 * 12;
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if (LIKELY(ip <= iend-7)) {
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ip += 3;
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} else {
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bitCount -= (int)(8 * (iend - 7 - ip));
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bitCount &= 31;
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ip = iend - 4;
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}
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bitStream = MEM_readLE32(ip) >> bitCount;
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repeats = FSE_ctz(~bitStream | 0x80000000) >> 1;
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}
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charnum += 3 * repeats;
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bitStream >>= 2 * repeats;
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bitCount += 2 * repeats;
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/* Add the final repeat which isn't 0b11. */
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assert((bitStream & 3) < 3);
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charnum += bitStream & 3;
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bitCount += 2;
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/* This is an error, but break and return an error
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* at the end, because returning out of a loop makes
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* it harder for the compiler to optimize.
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*/
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if (charnum >= maxSV1) break;
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/* We don't need to set the normalized count to 0
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* because we already memset the whole buffer to 0.
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*/
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if (LIKELY(ip <= iend-7) || (ip + (bitCount>>3) <= iend-4)) {
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assert((bitCount >> 3) <= 3); /* For first condition to work */
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ip += bitCount>>3;
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bitCount &= 7;
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} else {
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bitCount -= (int)(8 * (iend - 4 - ip));
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bitCount &= 31;
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ip = iend - 4;
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}
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bitStream = MEM_readLE32(ip) >> bitCount;
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}
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{
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int const max = (2*threshold-1) - remaining;
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int count;
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if ((bitStream & (threshold-1)) < (U32)max) {
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count = bitStream & (threshold-1);
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bitCount += nbBits-1;
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} else {
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count = bitStream & (2*threshold-1);
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if (count >= threshold) count -= max;
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bitCount += nbBits;
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}
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count--; /* extra accuracy */
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/* When it matters (small blocks), this is a
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* predictable branch, because we don't use -1.
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*/
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if (count >= 0) {
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remaining -= count;
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} else {
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assert(count == -1);
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remaining += count;
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}
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normalizedCounter[charnum++] = (short)count;
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previous0 = !count;
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assert(threshold > 1);
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if (remaining < threshold) {
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/* This branch can be folded into the
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* threshold update condition because we
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* know that threshold > 1.
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*/
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if (remaining <= 1) break;
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nbBits = BIT_highbit32(remaining) + 1;
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threshold = 1 << (nbBits - 1);
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}
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if (charnum >= maxSV1) break;
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if (LIKELY(ip <= iend-7) || (ip + (bitCount>>3) <= iend-4)) {
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ip += bitCount>>3;
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bitCount &= 7;
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} else {
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bitCount -= (int)(8 * (iend - 4 - ip));
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bitCount &= 31;
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ip = iend - 4;
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}
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bitStream = MEM_readLE32(ip) >> bitCount;
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} }
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if (remaining != 1) return ERROR(corruption_detected);
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/* Only possible when there are too many zeros. */
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if (charnum > maxSV1) return ERROR(maxSymbolValue_tooSmall);
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if (bitCount > 32) return ERROR(corruption_detected);
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*maxSVPtr = charnum-1;
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ip += (bitCount+7)>>3;
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return ip-istart;
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}
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/* Avoids the FORCE_INLINE of the _body() function. */
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static size_t FSE_readNCount_body_default(
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short* normalizedCounter, unsigned* maxSVPtr, unsigned* tableLogPtr,
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const void* headerBuffer, size_t hbSize)
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{
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return FSE_readNCount_body(normalizedCounter, maxSVPtr, tableLogPtr, headerBuffer, hbSize);
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}
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#if DYNAMIC_BMI2
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BMI2_TARGET_ATTRIBUTE static size_t FSE_readNCount_body_bmi2(
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short* normalizedCounter, unsigned* maxSVPtr, unsigned* tableLogPtr,
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const void* headerBuffer, size_t hbSize)
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{
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return FSE_readNCount_body(normalizedCounter, maxSVPtr, tableLogPtr, headerBuffer, hbSize);
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}
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#endif
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size_t FSE_readNCount_bmi2(
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short* normalizedCounter, unsigned* maxSVPtr, unsigned* tableLogPtr,
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const void* headerBuffer, size_t hbSize, int bmi2)
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{
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#if DYNAMIC_BMI2
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if (bmi2) {
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return FSE_readNCount_body_bmi2(normalizedCounter, maxSVPtr, tableLogPtr, headerBuffer, hbSize);
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}
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#endif
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(void)bmi2;
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return FSE_readNCount_body_default(normalizedCounter, maxSVPtr, tableLogPtr, headerBuffer, hbSize);
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}
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size_t FSE_readNCount(
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short* normalizedCounter, unsigned* maxSVPtr, unsigned* tableLogPtr,
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const void* headerBuffer, size_t hbSize)
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{
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return FSE_readNCount_bmi2(normalizedCounter, maxSVPtr, tableLogPtr, headerBuffer, hbSize, /* bmi2 */ 0);
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}
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/*! HUF_readStats() :
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Read compact Huffman tree, saved by HUF_writeCTable().
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`huffWeight` is destination buffer.
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`rankStats` is assumed to be a table of at least HUF_TABLELOG_MAX U32.
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@return : size read from `src` , or an error Code .
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Note : Needed by HUF_readCTable() and HUF_readDTableX?() .
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*/
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size_t HUF_readStats(BYTE* huffWeight, size_t hwSize, U32* rankStats,
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U32* nbSymbolsPtr, U32* tableLogPtr,
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const void* src, size_t srcSize)
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{
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U32 wksp[HUF_READ_STATS_WORKSPACE_SIZE_U32];
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return HUF_readStats_wksp(huffWeight, hwSize, rankStats, nbSymbolsPtr, tableLogPtr, src, srcSize, wksp, sizeof(wksp), /* bmi2 */ 0);
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}
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FORCE_INLINE_TEMPLATE size_t
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HUF_readStats_body(BYTE* huffWeight, size_t hwSize, U32* rankStats,
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U32* nbSymbolsPtr, U32* tableLogPtr,
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const void* src, size_t srcSize,
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void* workSpace, size_t wkspSize,
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int bmi2)
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{
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U32 weightTotal;
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const BYTE* ip = (const BYTE*) src;
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size_t iSize;
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size_t oSize;
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if (!srcSize) return ERROR(srcSize_wrong);
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iSize = ip[0];
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/* ZSTD_memset(huffWeight, 0, hwSize); *//* is not necessary, even though some analyzer complain ... */
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if (iSize >= 128) { /* special header */
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oSize = iSize - 127;
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iSize = ((oSize+1)/2);
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if (iSize+1 > srcSize) return ERROR(srcSize_wrong);
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if (oSize >= hwSize) return ERROR(corruption_detected);
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ip += 1;
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{ U32 n;
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for (n=0; n<oSize; n+=2) {
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huffWeight[n] = ip[n/2] >> 4;
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huffWeight[n+1] = ip[n/2] & 15;
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} } }
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else { /* header compressed with FSE (normal case) */
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if (iSize+1 > srcSize) return ERROR(srcSize_wrong);
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/* max (hwSize-1) values decoded, as last one is implied */
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oSize = FSE_decompress_wksp_bmi2(huffWeight, hwSize-1, ip+1, iSize, 6, workSpace, wkspSize, bmi2);
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if (FSE_isError(oSize)) return oSize;
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}
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/* collect weight stats */
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ZSTD_memset(rankStats, 0, (HUF_TABLELOG_MAX + 1) * sizeof(U32));
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weightTotal = 0;
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{ U32 n; for (n=0; n<oSize; n++) {
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if (huffWeight[n] > HUF_TABLELOG_MAX) return ERROR(corruption_detected);
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rankStats[huffWeight[n]]++;
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weightTotal += (1 << huffWeight[n]) >> 1;
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} }
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if (weightTotal == 0) return ERROR(corruption_detected);
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/* get last non-null symbol weight (implied, total must be 2^n) */
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{ U32 const tableLog = BIT_highbit32(weightTotal) + 1;
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if (tableLog > HUF_TABLELOG_MAX) return ERROR(corruption_detected);
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*tableLogPtr = tableLog;
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/* determine last weight */
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{ U32 const total = 1 << tableLog;
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U32 const rest = total - weightTotal;
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U32 const verif = 1 << BIT_highbit32(rest);
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U32 const lastWeight = BIT_highbit32(rest) + 1;
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if (verif != rest) return ERROR(corruption_detected); /* last value must be a clean power of 2 */
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huffWeight[oSize] = (BYTE)lastWeight;
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rankStats[lastWeight]++;
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} }
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/* check tree construction validity */
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if ((rankStats[1] < 2) || (rankStats[1] & 1)) return ERROR(corruption_detected); /* by construction : at least 2 elts of rank 1, must be even */
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/* results */
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*nbSymbolsPtr = (U32)(oSize+1);
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return iSize+1;
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}
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/* Avoids the FORCE_INLINE of the _body() function. */
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static size_t HUF_readStats_body_default(BYTE* huffWeight, size_t hwSize, U32* rankStats,
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U32* nbSymbolsPtr, U32* tableLogPtr,
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const void* src, size_t srcSize,
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void* workSpace, size_t wkspSize)
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{
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return HUF_readStats_body(huffWeight, hwSize, rankStats, nbSymbolsPtr, tableLogPtr, src, srcSize, workSpace, wkspSize, 0);
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}
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#if DYNAMIC_BMI2
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static BMI2_TARGET_ATTRIBUTE size_t HUF_readStats_body_bmi2(BYTE* huffWeight, size_t hwSize, U32* rankStats,
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U32* nbSymbolsPtr, U32* tableLogPtr,
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const void* src, size_t srcSize,
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void* workSpace, size_t wkspSize)
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{
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return HUF_readStats_body(huffWeight, hwSize, rankStats, nbSymbolsPtr, tableLogPtr, src, srcSize, workSpace, wkspSize, 1);
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}
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#endif
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size_t HUF_readStats_wksp(BYTE* huffWeight, size_t hwSize, U32* rankStats,
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U32* nbSymbolsPtr, U32* tableLogPtr,
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const void* src, size_t srcSize,
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void* workSpace, size_t wkspSize,
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int bmi2)
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{
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#if DYNAMIC_BMI2
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if (bmi2) {
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return HUF_readStats_body_bmi2(huffWeight, hwSize, rankStats, nbSymbolsPtr, tableLogPtr, src, srcSize, workSpace, wkspSize);
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}
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#endif
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(void)bmi2;
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return HUF_readStats_body_default(huffWeight, hwSize, rankStats, nbSymbolsPtr, tableLogPtr, src, srcSize, workSpace, wkspSize);
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}
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