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Diffstat (limited to 'src/zstd/lib/common/mem.h')
| -rw-r--r-- | src/zstd/lib/common/mem.h | 360 |
1 files changed, 360 insertions, 0 deletions
diff --git a/src/zstd/lib/common/mem.h b/src/zstd/lib/common/mem.h new file mode 100644 index 00000000..23335c31 --- /dev/null +++ b/src/zstd/lib/common/mem.h @@ -0,0 +1,360 @@ +/* + * Copyright (c) 2016-present, Yann Collet, Facebook, Inc. + * All rights reserved. + * + * This source code is licensed under both the BSD-style license (found in the + * LICENSE file in the root directory of this source tree) and the GPLv2 (found + * in the COPYING file in the root directory of this source tree). + * You may select, at your option, one of the above-listed licenses. + */ + +#ifndef MEM_H_MODULE +#define MEM_H_MODULE + +#if defined (__cplusplus) +extern "C" { +#endif + +/*-**************************************** +* Dependencies +******************************************/ +#include <stddef.h> /* size_t, ptrdiff_t */ +#include <string.h> /* memcpy */ + + +/*-**************************************** +* Compiler specifics +******************************************/ +#if defined(_MSC_VER) /* Visual Studio */ +# include <stdlib.h> /* _byteswap_ulong */ +# include <intrin.h> /* _byteswap_* */ +#endif +#if defined(__GNUC__) +# define MEM_STATIC static __inline __attribute__((unused)) +#elif defined (__cplusplus) || (defined (__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L) /* C99 */) +# define MEM_STATIC static inline +#elif defined(_MSC_VER) +# define MEM_STATIC static __inline +#else +# define MEM_STATIC static /* this version may generate warnings for unused static functions; disable the relevant warning */ +#endif + +/* code only tested on 32 and 64 bits systems */ +#define MEM_STATIC_ASSERT(c) { enum { MEM_static_assert = 1/(int)(!!(c)) }; } +MEM_STATIC void MEM_check(void) { MEM_STATIC_ASSERT((sizeof(size_t)==4) || (sizeof(size_t)==8)); } + + +/*-************************************************************** +* Basic Types +*****************************************************************/ +#if !defined (__VMS) && (defined (__cplusplus) || (defined (__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L) /* C99 */) ) +# include <stdint.h> + typedef uint8_t BYTE; + typedef uint16_t U16; + typedef int16_t S16; + typedef uint32_t U32; + typedef int32_t S32; + typedef uint64_t U64; + typedef int64_t S64; + typedef intptr_t iPtrDiff; + typedef uintptr_t uPtrDiff; +#else + typedef unsigned char BYTE; + typedef unsigned short U16; + typedef signed short S16; + typedef unsigned int U32; + typedef signed int S32; + typedef unsigned long long U64; + typedef signed long long S64; + typedef ptrdiff_t iPtrDiff; + typedef size_t uPtrDiff; +#endif + + +/*-************************************************************** +* Memory I/O +*****************************************************************/ +/* MEM_FORCE_MEMORY_ACCESS : + * By default, access to unaligned memory is controlled by `memcpy()`, which is safe and portable. + * Unfortunately, on some target/compiler combinations, the generated assembly is sub-optimal. + * The below switch allow to select different access method for improved performance. + * Method 0 (default) : use `memcpy()`. Safe and portable. + * Method 1 : `__packed` statement. It depends on compiler extension (i.e., not portable). + * This method is safe if your compiler supports it, and *generally* as fast or faster than `memcpy`. + * Method 2 : direct access. This method is portable but violate C standard. + * It can generate buggy code on targets depending on alignment. + * In some circumstances, it's the only known way to get the most performance (i.e. GCC + ARMv6) + * See http://fastcompression.blogspot.fr/2015/08/accessing-unaligned-memory.html for details. + * Prefer these methods in priority order (0 > 1 > 2) + */ +#ifndef MEM_FORCE_MEMORY_ACCESS /* can be defined externally, on command line for example */ +# if defined(__GNUC__) && ( defined(__ARM_ARCH_6__) || defined(__ARM_ARCH_6J__) || defined(__ARM_ARCH_6K__) || defined(__ARM_ARCH_6Z__) || defined(__ARM_ARCH_6ZK__) || defined(__ARM_ARCH_6T2__) ) +# define MEM_FORCE_MEMORY_ACCESS 2 +# elif defined(__INTEL_COMPILER) || defined(__GNUC__) +# define MEM_FORCE_MEMORY_ACCESS 1 +# endif +#endif + +MEM_STATIC unsigned MEM_32bits(void) { return sizeof(size_t)==4; } +MEM_STATIC unsigned MEM_64bits(void) { return sizeof(size_t)==8; } + +MEM_STATIC unsigned MEM_isLittleEndian(void) +{ + const union { U32 u; BYTE c[4]; } one = { 1 }; /* don't use static : performance detrimental */ + return one.c[0]; +} + +#if defined(MEM_FORCE_MEMORY_ACCESS) && (MEM_FORCE_MEMORY_ACCESS==2) + +/* violates C standard, by lying on structure alignment. +Only use if no other choice to achieve best performance on target platform */ +MEM_STATIC U16 MEM_read16(const void* memPtr) { return *(const U16*) memPtr; } +MEM_STATIC U32 MEM_read32(const void* memPtr) { return *(const U32*) memPtr; } +MEM_STATIC U64 MEM_read64(const void* memPtr) { return *(const U64*) memPtr; } +MEM_STATIC size_t MEM_readST(const void* memPtr) { return *(const size_t*) memPtr; } + +MEM_STATIC void MEM_write16(void* memPtr, U16 value) { *(U16*)memPtr = value; } +MEM_STATIC void MEM_write32(void* memPtr, U32 value) { *(U32*)memPtr = value; } +MEM_STATIC void MEM_write64(void* memPtr, U64 value) { *(U64*)memPtr = value; } + +#elif defined(MEM_FORCE_MEMORY_ACCESS) && (MEM_FORCE_MEMORY_ACCESS==1) + +/* __pack instructions are safer, but compiler specific, hence potentially problematic for some compilers */ +/* currently only defined for gcc and icc */ +#if defined(_MSC_VER) || (defined(__INTEL_COMPILER) && defined(WIN32)) + __pragma( pack(push, 1) ) + typedef union { U16 u16; U32 u32; U64 u64; size_t st; } unalign; + __pragma( pack(pop) ) +#else + typedef union { U16 u16; U32 u32; U64 u64; size_t st; } __attribute__((packed)) unalign; +#endif + +MEM_STATIC U16 MEM_read16(const void* ptr) { return ((const unalign*)ptr)->u16; } +MEM_STATIC U32 MEM_read32(const void* ptr) { return ((const unalign*)ptr)->u32; } +MEM_STATIC U64 MEM_read64(const void* ptr) { return ((const unalign*)ptr)->u64; } +MEM_STATIC size_t MEM_readST(const void* ptr) { return ((const unalign*)ptr)->st; } + +MEM_STATIC void MEM_write16(void* memPtr, U16 value) { ((unalign*)memPtr)->u16 = value; } +MEM_STATIC void MEM_write32(void* memPtr, U32 value) { ((unalign*)memPtr)->u32 = value; } +MEM_STATIC void MEM_write64(void* memPtr, U64 value) { ((unalign*)memPtr)->u64 = value; } + +#else + +/* default method, safe and standard. + can sometimes prove slower */ + +MEM_STATIC U16 MEM_read16(const void* memPtr) +{ + U16 val; memcpy(&val, memPtr, sizeof(val)); return val; +} + +MEM_STATIC U32 MEM_read32(const void* memPtr) +{ + U32 val; memcpy(&val, memPtr, sizeof(val)); return val; +} + +MEM_STATIC U64 MEM_read64(const void* memPtr) +{ + U64 val; memcpy(&val, memPtr, sizeof(val)); return val; +} + +MEM_STATIC size_t MEM_readST(const void* memPtr) +{ + size_t val; memcpy(&val, memPtr, sizeof(val)); return val; +} + +MEM_STATIC void MEM_write16(void* memPtr, U16 value) +{ + memcpy(memPtr, &value, sizeof(value)); +} + +MEM_STATIC void MEM_write32(void* memPtr, U32 value) +{ + memcpy(memPtr, &value, sizeof(value)); +} + +MEM_STATIC void MEM_write64(void* memPtr, U64 value) +{ + memcpy(memPtr, &value, sizeof(value)); +} + +#endif /* MEM_FORCE_MEMORY_ACCESS */ + +MEM_STATIC U32 MEM_swap32(U32 in) +{ +#if defined(_MSC_VER) /* Visual Studio */ + return _byteswap_ulong(in); +#elif defined (__GNUC__) && (__GNUC__ * 100 + __GNUC_MINOR__ >= 403) + return __builtin_bswap32(in); +#else + return ((in << 24) & 0xff000000 ) | + ((in << 8) & 0x00ff0000 ) | + ((in >> 8) & 0x0000ff00 ) | + ((in >> 24) & 0x000000ff ); +#endif +} + +MEM_STATIC U64 MEM_swap64(U64 in) +{ +#if defined(_MSC_VER) /* Visual Studio */ + return _byteswap_uint64(in); +#elif defined (__GNUC__) && (__GNUC__ * 100 + __GNUC_MINOR__ >= 403) + return __builtin_bswap64(in); +#else + return ((in << 56) & 0xff00000000000000ULL) | + ((in << 40) & 0x00ff000000000000ULL) | + ((in << 24) & 0x0000ff0000000000ULL) | + ((in << 8) & 0x000000ff00000000ULL) | + ((in >> 8) & 0x00000000ff000000ULL) | + ((in >> 24) & 0x0000000000ff0000ULL) | + ((in >> 40) & 0x000000000000ff00ULL) | + ((in >> 56) & 0x00000000000000ffULL); +#endif +} + +MEM_STATIC size_t MEM_swapST(size_t in) +{ + if (MEM_32bits()) + return (size_t)MEM_swap32((U32)in); + else + return (size_t)MEM_swap64((U64)in); +} + +/*=== Little endian r/w ===*/ + +MEM_STATIC U16 MEM_readLE16(const void* memPtr) +{ + if (MEM_isLittleEndian()) + return MEM_read16(memPtr); + else { + const BYTE* p = (const BYTE*)memPtr; + return (U16)(p[0] + (p[1]<<8)); + } +} + +MEM_STATIC void MEM_writeLE16(void* memPtr, U16 val) +{ + if (MEM_isLittleEndian()) { + MEM_write16(memPtr, val); + } else { + BYTE* p = (BYTE*)memPtr; + p[0] = (BYTE)val; + p[1] = (BYTE)(val>>8); + } +} + +MEM_STATIC U32 MEM_readLE24(const void* memPtr) +{ + return MEM_readLE16(memPtr) + (((const BYTE*)memPtr)[2] << 16); +} + +MEM_STATIC void MEM_writeLE24(void* memPtr, U32 val) +{ + MEM_writeLE16(memPtr, (U16)val); + ((BYTE*)memPtr)[2] = (BYTE)(val>>16); +} + +MEM_STATIC U32 MEM_readLE32(const void* memPtr) +{ + if (MEM_isLittleEndian()) + return MEM_read32(memPtr); + else + return MEM_swap32(MEM_read32(memPtr)); +} + +MEM_STATIC void MEM_writeLE32(void* memPtr, U32 val32) +{ + if (MEM_isLittleEndian()) + MEM_write32(memPtr, val32); + else + MEM_write32(memPtr, MEM_swap32(val32)); +} + +MEM_STATIC U64 MEM_readLE64(const void* memPtr) +{ + if (MEM_isLittleEndian()) + return MEM_read64(memPtr); + else + return MEM_swap64(MEM_read64(memPtr)); +} + +MEM_STATIC void MEM_writeLE64(void* memPtr, U64 val64) +{ + if (MEM_isLittleEndian()) + MEM_write64(memPtr, val64); + else + MEM_write64(memPtr, MEM_swap64(val64)); +} + +MEM_STATIC size_t MEM_readLEST(const void* memPtr) +{ + if (MEM_32bits()) + return (size_t)MEM_readLE32(memPtr); + else + return (size_t)MEM_readLE64(memPtr); +} + +MEM_STATIC void MEM_writeLEST(void* memPtr, size_t val) +{ + if (MEM_32bits()) + MEM_writeLE32(memPtr, (U32)val); + else + MEM_writeLE64(memPtr, (U64)val); +} + +/*=== Big endian r/w ===*/ + +MEM_STATIC U32 MEM_readBE32(const void* memPtr) +{ + if (MEM_isLittleEndian()) + return MEM_swap32(MEM_read32(memPtr)); + else + return MEM_read32(memPtr); +} + +MEM_STATIC void MEM_writeBE32(void* memPtr, U32 val32) +{ + if (MEM_isLittleEndian()) + MEM_write32(memPtr, MEM_swap32(val32)); + else + MEM_write32(memPtr, val32); +} + +MEM_STATIC U64 MEM_readBE64(const void* memPtr) +{ + if (MEM_isLittleEndian()) + return MEM_swap64(MEM_read64(memPtr)); + else + return MEM_read64(memPtr); +} + +MEM_STATIC void MEM_writeBE64(void* memPtr, U64 val64) +{ + if (MEM_isLittleEndian()) + MEM_write64(memPtr, MEM_swap64(val64)); + else + MEM_write64(memPtr, val64); +} + +MEM_STATIC size_t MEM_readBEST(const void* memPtr) +{ + if (MEM_32bits()) + return (size_t)MEM_readBE32(memPtr); + else + return (size_t)MEM_readBE64(memPtr); +} + +MEM_STATIC void MEM_writeBEST(void* memPtr, size_t val) +{ + if (MEM_32bits()) + MEM_writeBE32(memPtr, (U32)val); + else + MEM_writeBE64(memPtr, (U64)val); +} + + +#if defined (__cplusplus) +} +#endif + +#endif /* MEM_H_MODULE */ |