| /* ****************************************************************** |
| mem.h |
| low-level memory access routines |
| Copyright (C) 2013-2015, 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 : |
| - FSE source repository : https://github.com/Cyan4973/FiniteStateEntropy |
| - Public forum : https://groups.google.com/forum/#!forum/lz4c |
| ****************************************************************** */ |
| #ifndef MEM_H_MODULE |
| #define MEM_H_MODULE |
| |
| #if defined (__cplusplus) |
| extern "C" { |
| #endif |
| |
| /****************************************** |
| * Includes |
| ******************************************/ |
| #include <stddef.h> /* size_t, ptrdiff_t */ |
| #include <string.h> /* memcpy */ |
| |
| |
| /****************************************** |
| * Compiler-specific |
| ******************************************/ |
| #if defined(__GNUC__) |
| # define MEM_STATIC static __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 |
| |
| |
| /**************************************************************** |
| * Basic Types |
| *****************************************************************/ |
| #if 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; |
| #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; |
| #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 (ie, 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 generating assembly depending on alignment. |
| * But in some circumstances, it's the only known way to get the most performance (ie 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__) && ( defined(__ARM_ARCH_7__) || defined(__ARM_ARCH_7A__) || defined(__ARM_ARCH_7R__) || defined(__ARM_ARCH_7M__) || defined(__ARM_ARCH_7S__) )) |
| # define MEM_FORCE_MEMORY_ACCESS 1 |
| # endif |
| #endif |
| |
| MEM_STATIC unsigned MEM_32bits(void) { return sizeof(void*)==4; } |
| MEM_STATIC unsigned MEM_64bits(void) { return sizeof(void*)==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 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 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 */ |
| typedef union { U16 u16; U32 u32; U64 u64; } __attribute__((packed)) unalign; |
| |
| 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 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 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 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_readLE32(const void* memPtr) |
| { |
| if (MEM_isLittleEndian()) |
| return MEM_read32(memPtr); |
| else |
| { |
| const BYTE* p = (const BYTE*)memPtr; |
| return (U32)((U32)p[0] + ((U32)p[1]<<8) + ((U32)p[2]<<16) + ((U32)p[3]<<24)); |
| } |
| } |
| |
| MEM_STATIC void MEM_writeLE32(void* memPtr, U32 val32) |
| { |
| if (MEM_isLittleEndian()) |
| { |
| MEM_write32(memPtr, val32); |
| } |
| else |
| { |
| BYTE* p = (BYTE*)memPtr; |
| p[0] = (BYTE)val32; |
| p[1] = (BYTE)(val32>>8); |
| p[2] = (BYTE)(val32>>16); |
| p[3] = (BYTE)(val32>>24); |
| } |
| } |
| |
| MEM_STATIC U64 MEM_readLE64(const void* memPtr) |
| { |
| if (MEM_isLittleEndian()) |
| return MEM_read64(memPtr); |
| else |
| { |
| const BYTE* p = (const BYTE*)memPtr; |
| return (U64)((U64)p[0] + ((U64)p[1]<<8) + ((U64)p[2]<<16) + ((U64)p[3]<<24) |
| + ((U64)p[4]<<32) + ((U64)p[5]<<40) + ((U64)p[6]<<48) + ((U64)p[7]<<56)); |
| } |
| } |
| |
| MEM_STATIC void MEM_writeLE64(void* memPtr, U64 val64) |
| { |
| if (MEM_isLittleEndian()) |
| { |
| MEM_write64(memPtr, val64); |
| } |
| else |
| { |
| BYTE* p = (BYTE*)memPtr; |
| p[0] = (BYTE)val64; |
| p[1] = (BYTE)(val64>>8); |
| p[2] = (BYTE)(val64>>16); |
| p[3] = (BYTE)(val64>>24); |
| p[4] = (BYTE)(val64>>32); |
| p[5] = (BYTE)(val64>>40); |
| p[6] = (BYTE)(val64>>48); |
| p[7] = (BYTE)(val64>>56); |
| } |
| } |
| |
| 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); |
| } |
| |
| #if defined (__cplusplus) |
| } |
| #endif |
| |
| #endif /* MEM_H_MODULE */ |
| |