1 /* 2 * Copyright (c) 2016-2020, Yann Collet, Facebook, Inc. 3 * All rights reserved. 4 * 5 * This source code is licensed under both the BSD-style license (found in the 6 * LICENSE file in the root directory of this source tree) and the GPLv2 (found 7 * in the COPYING file in the root directory of this source tree). 8 * You may select, at your option, one of the above-listed licenses. 9 */ 10 11 #ifndef MEM_H_MODULE 12 #define MEM_H_MODULE 13 14 #if defined (__cplusplus) 15 extern "C" { 16 #endif 17 18 /*-**************************************** 19 * Dependencies 20 ******************************************/ 21 #include <stddef.h> /* size_t, ptrdiff_t */ 22 #include "compiler.h" /* __has_builtin */ 23 #include "debug.h" /* DEBUG_STATIC_ASSERT */ 24 #include "zstd_deps.h" /* ZSTD_memcpy */ 25 26 27 /*-**************************************** 28 * Compiler specifics 29 ******************************************/ 30 #if defined(_MSC_VER) /* Visual Studio */ 31 # include <stdlib.h> /* _byteswap_ulong */ 32 # include <intrin.h> /* _byteswap_* */ 33 #endif 34 #if defined(__GNUC__) 35 # define MEM_STATIC static __inline __attribute__((unused)) 36 #elif defined (__cplusplus) || (defined (__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L) /* C99 */) 37 # define MEM_STATIC static inline 38 #elif defined(_MSC_VER) 39 # define MEM_STATIC static __inline 40 #else 41 # define MEM_STATIC static /* this version may generate warnings for unused static functions; disable the relevant warning */ 42 #endif 43 44 /*-************************************************************** 45 * Basic Types 46 *****************************************************************/ 47 #if !defined (__VMS) && (defined (__cplusplus) || (defined (__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L) /* C99 */) ) 48 # if defined(_AIX) 49 # include <inttypes.h> 50 # else 51 # include <stdint.h> /* intptr_t */ 52 # endif 53 typedef uint8_t BYTE; 54 typedef uint16_t U16; 55 typedef int16_t S16; 56 typedef uint32_t U32; 57 typedef int32_t S32; 58 typedef uint64_t U64; 59 typedef int64_t S64; 60 #else 61 # include <limits.h> 62 #if CHAR_BIT != 8 63 # error "this implementation requires char to be exactly 8-bit type" 64 #endif 65 typedef unsigned char BYTE; 66 #if USHRT_MAX != 65535 67 # error "this implementation requires short to be exactly 16-bit type" 68 #endif 69 typedef unsigned short U16; 70 typedef signed short S16; 71 #if UINT_MAX != 4294967295 72 # error "this implementation requires int to be exactly 32-bit type" 73 #endif 74 typedef unsigned int U32; 75 typedef signed int S32; 76 /* note : there are no limits defined for long long type in C90. 77 * limits exist in C99, however, in such case, <stdint.h> is preferred */ 78 typedef unsigned long long U64; 79 typedef signed long long S64; 80 #endif 81 82 83 /*-************************************************************** 84 * Memory I/O API 85 *****************************************************************/ 86 /*=== Static platform detection ===*/ 87 MEM_STATIC unsigned MEM_32bits(void); 88 MEM_STATIC unsigned MEM_64bits(void); 89 MEM_STATIC unsigned MEM_isLittleEndian(void); 90 91 /*=== Native unaligned read/write ===*/ 92 MEM_STATIC U16 MEM_read16(const void* memPtr); 93 MEM_STATIC U32 MEM_read32(const void* memPtr); 94 MEM_STATIC U64 MEM_read64(const void* memPtr); 95 MEM_STATIC size_t MEM_readST(const void* memPtr); 96 97 MEM_STATIC void MEM_write16(void* memPtr, U16 value); 98 MEM_STATIC void MEM_write32(void* memPtr, U32 value); 99 MEM_STATIC void MEM_write64(void* memPtr, U64 value); 100 101 /*=== Little endian unaligned read/write ===*/ 102 MEM_STATIC U16 MEM_readLE16(const void* memPtr); 103 MEM_STATIC U32 MEM_readLE24(const void* memPtr); 104 MEM_STATIC U32 MEM_readLE32(const void* memPtr); 105 MEM_STATIC U64 MEM_readLE64(const void* memPtr); 106 MEM_STATIC size_t MEM_readLEST(const void* memPtr); 107 108 MEM_STATIC void MEM_writeLE16(void* memPtr, U16 val); 109 MEM_STATIC void MEM_writeLE24(void* memPtr, U32 val); 110 MEM_STATIC void MEM_writeLE32(void* memPtr, U32 val32); 111 MEM_STATIC void MEM_writeLE64(void* memPtr, U64 val64); 112 MEM_STATIC void MEM_writeLEST(void* memPtr, size_t val); 113 114 /*=== Big endian unaligned read/write ===*/ 115 MEM_STATIC U32 MEM_readBE32(const void* memPtr); 116 MEM_STATIC U64 MEM_readBE64(const void* memPtr); 117 MEM_STATIC size_t MEM_readBEST(const void* memPtr); 118 119 MEM_STATIC void MEM_writeBE32(void* memPtr, U32 val32); 120 MEM_STATIC void MEM_writeBE64(void* memPtr, U64 val64); 121 MEM_STATIC void MEM_writeBEST(void* memPtr, size_t val); 122 123 /*=== Byteswap ===*/ 124 MEM_STATIC U32 MEM_swap32(U32 in); 125 MEM_STATIC U64 MEM_swap64(U64 in); 126 MEM_STATIC size_t MEM_swapST(size_t in); 127 128 129 /*-************************************************************** 130 * Memory I/O Implementation 131 *****************************************************************/ 132 /* MEM_FORCE_MEMORY_ACCESS : 133 * By default, access to unaligned memory is controlled by `memcpy()`, which is safe and portable. 134 * Unfortunately, on some target/compiler combinations, the generated assembly is sub-optimal. 135 * The below switch allow to select different access method for improved performance. 136 * Method 0 (default) : use `memcpy()`. Safe and portable. 137 * Method 1 : `__packed` statement. It depends on compiler extension (i.e., not portable). 138 * This method is safe if your compiler supports it, and *generally* as fast or faster than `memcpy`. 139 * Method 2 : direct access. This method is portable but violate C standard. 140 * It can generate buggy code on targets depending on alignment. 141 * In some circumstances, it's the only known way to get the most performance (i.e. GCC + ARMv6) 142 * See http://fastcompression.blogspot.fr/2015/08/accessing-unaligned-memory.html for details. 143 * Prefer these methods in priority order (0 > 1 > 2) 144 */ 145 #ifndef MEM_FORCE_MEMORY_ACCESS /* can be defined externally, on command line for example */ 146 # 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__) ) 147 # define MEM_FORCE_MEMORY_ACCESS 2 148 # elif defined(__INTEL_COMPILER) || defined(__GNUC__) || defined(__ICCARM__) 149 # define MEM_FORCE_MEMORY_ACCESS 1 150 # endif 151 #endif 152 153 MEM_STATIC unsigned MEM_32bits(void) { return sizeof(size_t)==4; } 154 MEM_STATIC unsigned MEM_64bits(void) { return sizeof(size_t)==8; } 155 156 MEM_STATIC unsigned MEM_isLittleEndian(void) 157 { 158 const union { U32 u; BYTE c[4]; } one = { 1 }; /* don't use static : performance detrimental */ 159 return one.c[0]; 160 } 161 162 #if defined(MEM_FORCE_MEMORY_ACCESS) && (MEM_FORCE_MEMORY_ACCESS==2) 163 164 /* violates C standard, by lying on structure alignment. 165 Only use if no other choice to achieve best performance on target platform */ 166 MEM_STATIC U16 MEM_read16(const void* memPtr) { return *(const U16*) memPtr; } 167 MEM_STATIC U32 MEM_read32(const void* memPtr) { return *(const U32*) memPtr; } 168 MEM_STATIC U64 MEM_read64(const void* memPtr) { return *(const U64*) memPtr; } 169 MEM_STATIC size_t MEM_readST(const void* memPtr) { return *(const size_t*) memPtr; } 170 171 MEM_STATIC void MEM_write16(void* memPtr, U16 value) { *(U16*)memPtr = value; } 172 MEM_STATIC void MEM_write32(void* memPtr, U32 value) { *(U32*)memPtr = value; } 173 MEM_STATIC void MEM_write64(void* memPtr, U64 value) { *(U64*)memPtr = value; } 174 175 #elif defined(MEM_FORCE_MEMORY_ACCESS) && (MEM_FORCE_MEMORY_ACCESS==1) 176 177 /* __pack instructions are safer, but compiler specific, hence potentially problematic for some compilers */ 178 /* currently only defined for gcc and icc */ 179 #if defined(_MSC_VER) || (defined(__INTEL_COMPILER) && defined(WIN32)) 180 __pragma( pack(push, 1) ) 181 typedef struct { U16 v; } unalign16; 182 typedef struct { U32 v; } unalign32; 183 typedef struct { U64 v; } unalign64; 184 typedef struct { size_t v; } unalignArch; 185 __pragma( pack(pop) ) 186 #else 187 typedef struct { U16 v; } __attribute__((packed)) unalign16; 188 typedef struct { U32 v; } __attribute__((packed)) unalign32; 189 typedef struct { U64 v; } __attribute__((packed)) unalign64; 190 typedef struct { size_t v; } __attribute__((packed)) unalignArch; 191 #endif 192 193 MEM_STATIC U16 MEM_read16(const void* ptr) { return ((const unalign16*)ptr)->v; } 194 MEM_STATIC U32 MEM_read32(const void* ptr) { return ((const unalign32*)ptr)->v; } 195 MEM_STATIC U64 MEM_read64(const void* ptr) { return ((const unalign64*)ptr)->v; } 196 MEM_STATIC size_t MEM_readST(const void* ptr) { return ((const unalignArch*)ptr)->v; } 197 198 MEM_STATIC void MEM_write16(void* memPtr, U16 value) { ((unalign16*)memPtr)->v = value; } 199 MEM_STATIC void MEM_write32(void* memPtr, U32 value) { ((unalign32*)memPtr)->v = value; } 200 MEM_STATIC void MEM_write64(void* memPtr, U64 value) { ((unalign64*)memPtr)->v = value; } 201 202 #else 203 204 /* default method, safe and standard. 205 can sometimes prove slower */ 206 207 MEM_STATIC U16 MEM_read16(const void* memPtr) 208 { 209 U16 val; ZSTD_memcpy(&val, memPtr, sizeof(val)); return val; 210 } 211 212 MEM_STATIC U32 MEM_read32(const void* memPtr) 213 { 214 U32 val; ZSTD_memcpy(&val, memPtr, sizeof(val)); return val; 215 } 216 217 MEM_STATIC U64 MEM_read64(const void* memPtr) 218 { 219 U64 val; ZSTD_memcpy(&val, memPtr, sizeof(val)); return val; 220 } 221 222 MEM_STATIC size_t MEM_readST(const void* memPtr) 223 { 224 size_t val; ZSTD_memcpy(&val, memPtr, sizeof(val)); return val; 225 } 226 227 MEM_STATIC void MEM_write16(void* memPtr, U16 value) 228 { 229 ZSTD_memcpy(memPtr, &value, sizeof(value)); 230 } 231 232 MEM_STATIC void MEM_write32(void* memPtr, U32 value) 233 { 234 ZSTD_memcpy(memPtr, &value, sizeof(value)); 235 } 236 237 MEM_STATIC void MEM_write64(void* memPtr, U64 value) 238 { 239 ZSTD_memcpy(memPtr, &value, sizeof(value)); 240 } 241 242 #endif /* MEM_FORCE_MEMORY_ACCESS */ 243 244 MEM_STATIC U32 MEM_swap32(U32 in) 245 { 246 #if defined(_MSC_VER) /* Visual Studio */ 247 return _byteswap_ulong(in); 248 #elif (defined (__GNUC__) && (__GNUC__ * 100 + __GNUC_MINOR__ >= 403)) \ 249 || (defined(__clang__) && __has_builtin(__builtin_bswap32)) 250 return __builtin_bswap32(in); 251 #else 252 return ((in << 24) & 0xff000000 ) | 253 ((in << 8) & 0x00ff0000 ) | 254 ((in >> 8) & 0x0000ff00 ) | 255 ((in >> 24) & 0x000000ff ); 256 #endif 257 } 258 259 MEM_STATIC U64 MEM_swap64(U64 in) 260 { 261 #if defined(_MSC_VER) /* Visual Studio */ 262 return _byteswap_uint64(in); 263 #elif (defined (__GNUC__) && (__GNUC__ * 100 + __GNUC_MINOR__ >= 403)) \ 264 || (defined(__clang__) && __has_builtin(__builtin_bswap64)) 265 return __builtin_bswap64(in); 266 #else 267 return ((in << 56) & 0xff00000000000000ULL) | 268 ((in << 40) & 0x00ff000000000000ULL) | 269 ((in << 24) & 0x0000ff0000000000ULL) | 270 ((in << 8) & 0x000000ff00000000ULL) | 271 ((in >> 8) & 0x00000000ff000000ULL) | 272 ((in >> 24) & 0x0000000000ff0000ULL) | 273 ((in >> 40) & 0x000000000000ff00ULL) | 274 ((in >> 56) & 0x00000000000000ffULL); 275 #endif 276 } 277 278 MEM_STATIC size_t MEM_swapST(size_t in) 279 { 280 if (MEM_32bits()) 281 return (size_t)MEM_swap32((U32)in); 282 else 283 return (size_t)MEM_swap64((U64)in); 284 } 285 286 /*=== Little endian r/w ===*/ 287 288 MEM_STATIC U16 MEM_readLE16(const void* memPtr) 289 { 290 if (MEM_isLittleEndian()) 291 return MEM_read16(memPtr); 292 else { 293 const BYTE* p = (const BYTE*)memPtr; 294 return (U16)(p[0] + (p[1]<<8)); 295 } 296 } 297 298 MEM_STATIC void MEM_writeLE16(void* memPtr, U16 val) 299 { 300 if (MEM_isLittleEndian()) { 301 MEM_write16(memPtr, val); 302 } else { 303 BYTE* p = (BYTE*)memPtr; 304 p[0] = (BYTE)val; 305 p[1] = (BYTE)(val>>8); 306 } 307 } 308 309 MEM_STATIC U32 MEM_readLE24(const void* memPtr) 310 { 311 return MEM_readLE16(memPtr) + (((const BYTE*)memPtr)[2] << 16); 312 } 313 314 MEM_STATIC void MEM_writeLE24(void* memPtr, U32 val) 315 { 316 MEM_writeLE16(memPtr, (U16)val); 317 ((BYTE*)memPtr)[2] = (BYTE)(val>>16); 318 } 319 320 MEM_STATIC U32 MEM_readLE32(const void* memPtr) 321 { 322 if (MEM_isLittleEndian()) 323 return MEM_read32(memPtr); 324 else 325 return MEM_swap32(MEM_read32(memPtr)); 326 } 327 328 MEM_STATIC void MEM_writeLE32(void* memPtr, U32 val32) 329 { 330 if (MEM_isLittleEndian()) 331 MEM_write32(memPtr, val32); 332 else 333 MEM_write32(memPtr, MEM_swap32(val32)); 334 } 335 336 MEM_STATIC U64 MEM_readLE64(const void* memPtr) 337 { 338 if (MEM_isLittleEndian()) 339 return MEM_read64(memPtr); 340 else 341 return MEM_swap64(MEM_read64(memPtr)); 342 } 343 344 MEM_STATIC void MEM_writeLE64(void* memPtr, U64 val64) 345 { 346 if (MEM_isLittleEndian()) 347 MEM_write64(memPtr, val64); 348 else 349 MEM_write64(memPtr, MEM_swap64(val64)); 350 } 351 352 MEM_STATIC size_t MEM_readLEST(const void* memPtr) 353 { 354 if (MEM_32bits()) 355 return (size_t)MEM_readLE32(memPtr); 356 else 357 return (size_t)MEM_readLE64(memPtr); 358 } 359 360 MEM_STATIC void MEM_writeLEST(void* memPtr, size_t val) 361 { 362 if (MEM_32bits()) 363 MEM_writeLE32(memPtr, (U32)val); 364 else 365 MEM_writeLE64(memPtr, (U64)val); 366 } 367 368 /*=== Big endian r/w ===*/ 369 370 MEM_STATIC U32 MEM_readBE32(const void* memPtr) 371 { 372 if (MEM_isLittleEndian()) 373 return MEM_swap32(MEM_read32(memPtr)); 374 else 375 return MEM_read32(memPtr); 376 } 377 378 MEM_STATIC void MEM_writeBE32(void* memPtr, U32 val32) 379 { 380 if (MEM_isLittleEndian()) 381 MEM_write32(memPtr, MEM_swap32(val32)); 382 else 383 MEM_write32(memPtr, val32); 384 } 385 386 MEM_STATIC U64 MEM_readBE64(const void* memPtr) 387 { 388 if (MEM_isLittleEndian()) 389 return MEM_swap64(MEM_read64(memPtr)); 390 else 391 return MEM_read64(memPtr); 392 } 393 394 MEM_STATIC void MEM_writeBE64(void* memPtr, U64 val64) 395 { 396 if (MEM_isLittleEndian()) 397 MEM_write64(memPtr, MEM_swap64(val64)); 398 else 399 MEM_write64(memPtr, val64); 400 } 401 402 MEM_STATIC size_t MEM_readBEST(const void* memPtr) 403 { 404 if (MEM_32bits()) 405 return (size_t)MEM_readBE32(memPtr); 406 else 407 return (size_t)MEM_readBE64(memPtr); 408 } 409 410 MEM_STATIC void MEM_writeBEST(void* memPtr, size_t val) 411 { 412 if (MEM_32bits()) 413 MEM_writeBE32(memPtr, (U32)val); 414 else 415 MEM_writeBE64(memPtr, (U64)val); 416 } 417 418 /* code only tested on 32 and 64 bits systems */ 419 MEM_STATIC void MEM_check(void) { DEBUG_STATIC_ASSERT((sizeof(size_t)==4) || (sizeof(size_t)==8)); } 420 421 422 #if defined (__cplusplus) 423 } 424 #endif 425 426 #endif /* MEM_H_MODULE */ 427