diff options
Diffstat (limited to 'thirdparty/zstd/common/entropy_common.c')
| -rw-r--r-- | thirdparty/zstd/common/entropy_common.c | 230 |
1 files changed, 188 insertions, 42 deletions
diff --git a/thirdparty/zstd/common/entropy_common.c b/thirdparty/zstd/common/entropy_common.c index 9d3e4e8e36..f9fcb1acfc 100644 --- a/thirdparty/zstd/common/entropy_common.c +++ b/thirdparty/zstd/common/entropy_common.c @@ -38,8 +38,31 @@ const char* HUF_getErrorName(size_t code) { return ERR_getErrorName(code); } /*-************************************************************** * FSE NCount encoding-decoding ****************************************************************/ -size_t FSE_readNCount (short* normalizedCounter, unsigned* maxSVPtr, unsigned* tableLogPtr, - const void* headerBuffer, size_t hbSize) +static U32 FSE_ctz(U32 val) +{ + assert(val != 0); + { +# if defined(_MSC_VER) /* Visual */ + unsigned long r=0; + return _BitScanForward(&r, val) ? (unsigned)r : 0; +# elif defined(__GNUC__) && (__GNUC__ >= 3) /* GCC Intrinsic */ + return __builtin_ctz(val); +# elif defined(__ICCARM__) /* IAR Intrinsic */ + return __CTZ(val); +# else /* Software version */ + U32 count = 0; + while ((val & 1) == 0) { + val >>= 1; + ++count; + } + return count; +# endif + } +} + +FORCE_INLINE_TEMPLATE +size_t FSE_readNCount_body(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; @@ -50,23 +73,23 @@ size_t FSE_readNCount (short* normalizedCounter, unsigned* maxSVPtr, unsigned* t U32 bitStream; int bitCount; unsigned charnum = 0; + unsigned const maxSV1 = *maxSVPtr + 1; int previous0 = 0; - if (hbSize < 4) { - /* This function only works when hbSize >= 4 */ - char buffer[4]; - memset(buffer, 0, sizeof(buffer)); - memcpy(buffer, headerBuffer, hbSize); + if (hbSize < 8) { + /* This function only works when hbSize >= 8 */ + char buffer[8] = {0}; + ZSTD_memcpy(buffer, headerBuffer, hbSize); { size_t const countSize = FSE_readNCount(normalizedCounter, maxSVPtr, tableLogPtr, buffer, sizeof(buffer)); if (FSE_isError(countSize)) return countSize; if (countSize > hbSize) return ERROR(corruption_detected); return countSize; } } - assert(hbSize >= 4); + assert(hbSize >= 8); /* init */ - memset(normalizedCounter, 0, (*maxSVPtr+1) * sizeof(normalizedCounter[0])); /* all symbols not present in NCount have a frequency of 0 */ + ZSTD_memset(normalizedCounter, 0, (*maxSVPtr+1) * sizeof(normalizedCounter[0])); /* all symbols not present in NCount have a frequency of 0 */ bitStream = MEM_readLE32(ip); nbBits = (bitStream & 0xF) + FSE_MIN_TABLELOG; /* extract tableLog */ if (nbBits > FSE_TABLELOG_ABSOLUTE_MAX) return ERROR(tableLog_tooLarge); @@ -77,36 +100,58 @@ size_t FSE_readNCount (short* normalizedCounter, unsigned* maxSVPtr, unsigned* t threshold = 1<<nbBits; nbBits++; - while ((remaining>1) & (charnum<=*maxSVPtr)) { + for (;;) { if (previous0) { - unsigned n0 = charnum; - while ((bitStream & 0xFFFF) == 0xFFFF) { - n0 += 24; - if (ip < iend-5) { - ip += 2; - bitStream = MEM_readLE32(ip) >> bitCount; + /* Count the number of repeats. Each time the + * 2-bit repeat code is 0b11 there is another + * repeat. + * Avoid UB by setting the high bit to 1. + */ + int repeats = FSE_ctz(~bitStream | 0x80000000) >> 1; + while (repeats >= 12) { + charnum += 3 * 12; + if (LIKELY(ip <= iend-7)) { + ip += 3; } else { - bitStream >>= 16; - bitCount += 16; - } } - while ((bitStream & 3) == 3) { - n0 += 3; - bitStream >>= 2; - bitCount += 2; + bitCount -= (int)(8 * (iend - 7 - ip)); + bitCount &= 31; + ip = iend - 4; + } + bitStream = MEM_readLE32(ip) >> bitCount; + repeats = FSE_ctz(~bitStream | 0x80000000) >> 1; } - n0 += bitStream & 3; + charnum += 3 * repeats; + bitStream >>= 2 * repeats; + bitCount += 2 * repeats; + + /* Add the final repeat which isn't 0b11. */ + assert((bitStream & 3) < 3); + charnum += 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)) { + + /* This is an error, but break and return an error + * at the end, because returning out of a loop makes + * it harder for the compiler to optimize. + */ + if (charnum >= maxSV1) break; + + /* We don't need to set the normalized count to 0 + * because we already memset the whole buffer to 0. + */ + + if (LIKELY(ip <= iend-7) || (ip + (bitCount>>3) <= iend-4)) { assert((bitCount >> 3) <= 3); /* For first condition to work */ ip += bitCount>>3; bitCount &= 7; - bitStream = MEM_readLE32(ip) >> bitCount; } else { - bitStream >>= 2; - } } - { int const max = (2*threshold-1) - remaining; + bitCount -= (int)(8 * (iend - 4 - ip)); + bitCount &= 31; + ip = iend - 4; + } + bitStream = MEM_readLE32(ip) >> bitCount; + } + { + int const max = (2*threshold-1) - remaining; int count; if ((bitStream & (threshold-1)) < (U32)max) { @@ -119,24 +164,43 @@ size_t FSE_readNCount (short* normalizedCounter, unsigned* maxSVPtr, unsigned* t } count--; /* extra accuracy */ - remaining -= count < 0 ? -count : count; /* -1 means +1 */ + /* When it matters (small blocks), this is a + * predictable branch, because we don't use -1. + */ + if (count >= 0) { + remaining -= count; + } else { + assert(count == -1); + remaining += count; + } normalizedCounter[charnum++] = (short)count; previous0 = !count; - while (remaining < threshold) { - nbBits--; - threshold >>= 1; + + assert(threshold > 1); + if (remaining < threshold) { + /* This branch can be folded into the + * threshold update condition because we + * know that threshold > 1. + */ + if (remaining <= 1) break; + nbBits = BIT_highbit32(remaining) + 1; + threshold = 1 << (nbBits - 1); } + if (charnum >= maxSV1) break; - if ((ip <= iend-7) || (ip + (bitCount>>3) <= iend-4)) { + if (LIKELY(ip <= iend-7) || (ip + (bitCount>>3) <= iend-4)) { ip += bitCount>>3; bitCount &= 7; } else { bitCount -= (int)(8 * (iend - 4 - ip)); + bitCount &= 31; ip = iend - 4; } - bitStream = MEM_readLE32(ip) >> (bitCount & 31); - } } /* while ((remaining>1) & (charnum<=*maxSVPtr)) */ + bitStream = MEM_readLE32(ip) >> bitCount; + } } if (remaining != 1) return ERROR(corruption_detected); + /* Only possible when there are too many zeros. */ + if (charnum > maxSV1) return ERROR(maxSymbolValue_tooSmall); if (bitCount > 32) return ERROR(corruption_detected); *maxSVPtr = charnum-1; @@ -144,6 +208,43 @@ size_t FSE_readNCount (short* normalizedCounter, unsigned* maxSVPtr, unsigned* t return ip-istart; } +/* Avoids the FORCE_INLINE of the _body() function. */ +static size_t FSE_readNCount_body_default( + short* normalizedCounter, unsigned* maxSVPtr, unsigned* tableLogPtr, + const void* headerBuffer, size_t hbSize) +{ + return FSE_readNCount_body(normalizedCounter, maxSVPtr, tableLogPtr, headerBuffer, hbSize); +} + +#if DYNAMIC_BMI2 +TARGET_ATTRIBUTE("bmi2") static size_t FSE_readNCount_body_bmi2( + short* normalizedCounter, unsigned* maxSVPtr, unsigned* tableLogPtr, + const void* headerBuffer, size_t hbSize) +{ + return FSE_readNCount_body(normalizedCounter, maxSVPtr, tableLogPtr, headerBuffer, hbSize); +} +#endif + +size_t FSE_readNCount_bmi2( + short* normalizedCounter, unsigned* maxSVPtr, unsigned* tableLogPtr, + const void* headerBuffer, size_t hbSize, int bmi2) +{ +#if DYNAMIC_BMI2 + if (bmi2) { + return FSE_readNCount_body_bmi2(normalizedCounter, maxSVPtr, tableLogPtr, headerBuffer, hbSize); + } +#endif + (void)bmi2; + return FSE_readNCount_body_default(normalizedCounter, maxSVPtr, tableLogPtr, headerBuffer, hbSize); +} + +size_t FSE_readNCount( + short* normalizedCounter, unsigned* maxSVPtr, unsigned* tableLogPtr, + const void* headerBuffer, size_t hbSize) +{ + return FSE_readNCount_bmi2(normalizedCounter, maxSVPtr, tableLogPtr, headerBuffer, hbSize, /* bmi2 */ 0); +} + /*! HUF_readStats() : Read compact Huffman tree, saved by HUF_writeCTable(). @@ -156,6 +257,17 @@ size_t HUF_readStats(BYTE* huffWeight, size_t hwSize, U32* rankStats, U32* nbSymbolsPtr, U32* tableLogPtr, const void* src, size_t srcSize) { + U32 wksp[HUF_READ_STATS_WORKSPACE_SIZE_U32]; + return HUF_readStats_wksp(huffWeight, hwSize, rankStats, nbSymbolsPtr, tableLogPtr, src, srcSize, wksp, sizeof(wksp), /* bmi2 */ 0); +} + +FORCE_INLINE_TEMPLATE size_t +HUF_readStats_body(BYTE* huffWeight, size_t hwSize, U32* rankStats, + U32* nbSymbolsPtr, U32* tableLogPtr, + const void* src, size_t srcSize, + void* workSpace, size_t wkspSize, + int bmi2) +{ U32 weightTotal; const BYTE* ip = (const BYTE*) src; size_t iSize; @@ -163,7 +275,7 @@ size_t HUF_readStats(BYTE* huffWeight, size_t hwSize, U32* rankStats, if (!srcSize) return ERROR(srcSize_wrong); iSize = ip[0]; - /* memset(huffWeight, 0, hwSize); *//* is not necessary, even though some analyzer complain ... */ + /* ZSTD_memset(huffWeight, 0, hwSize); *//* is not necessary, even though some analyzer complain ... */ if (iSize >= 128) { /* special header */ oSize = iSize - 127; @@ -177,14 +289,14 @@ size_t HUF_readStats(BYTE* huffWeight, size_t hwSize, U32* rankStats, huffWeight[n+1] = ip[n/2] & 15; } } } else { /* header compressed with FSE (normal case) */ - FSE_DTable fseWorkspace[FSE_DTABLE_SIZE_U32(6)]; /* 6 is max possible tableLog for HUF header (maybe even 5, to be tested) */ if (iSize+1 > srcSize) return ERROR(srcSize_wrong); - oSize = FSE_decompress_wksp(huffWeight, hwSize-1, ip+1, iSize, fseWorkspace, 6); /* max (hwSize-1) values decoded, as last one is implied */ + /* max (hwSize-1) values decoded, as last one is implied */ + oSize = FSE_decompress_wksp_bmi2(huffWeight, hwSize-1, ip+1, iSize, 6, workSpace, wkspSize, bmi2); if (FSE_isError(oSize)) return oSize; } /* collect weight stats */ - memset(rankStats, 0, (HUF_TABLELOG_MAX + 1) * sizeof(U32)); + ZSTD_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); @@ -214,3 +326,37 @@ size_t HUF_readStats(BYTE* huffWeight, size_t hwSize, U32* rankStats, *nbSymbolsPtr = (U32)(oSize+1); return iSize+1; } + +/* Avoids the FORCE_INLINE of the _body() function. */ +static size_t HUF_readStats_body_default(BYTE* huffWeight, size_t hwSize, U32* rankStats, + U32* nbSymbolsPtr, U32* tableLogPtr, + const void* src, size_t srcSize, + void* workSpace, size_t wkspSize) +{ + return HUF_readStats_body(huffWeight, hwSize, rankStats, nbSymbolsPtr, tableLogPtr, src, srcSize, workSpace, wkspSize, 0); +} + +#if DYNAMIC_BMI2 +static TARGET_ATTRIBUTE("bmi2") size_t HUF_readStats_body_bmi2(BYTE* huffWeight, size_t hwSize, U32* rankStats, + U32* nbSymbolsPtr, U32* tableLogPtr, + const void* src, size_t srcSize, + void* workSpace, size_t wkspSize) +{ + return HUF_readStats_body(huffWeight, hwSize, rankStats, nbSymbolsPtr, tableLogPtr, src, srcSize, workSpace, wkspSize, 1); +} +#endif + +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 wkspSize, + int bmi2) +{ +#if DYNAMIC_BMI2 + if (bmi2) { + return HUF_readStats_body_bmi2(huffWeight, hwSize, rankStats, nbSymbolsPtr, tableLogPtr, src, srcSize, workSpace, wkspSize); + } +#endif + (void)bmi2; + return HUF_readStats_body_default(huffWeight, hwSize, rankStats, nbSymbolsPtr, tableLogPtr, src, srcSize, workSpace, wkspSize); +} |