1 /* 2 * Copyright (c) Meta Platforms, Inc. and affiliates. 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 35 /*-************************************************************** 36 * Basic Types 37 *****************************************************************/ 38 #if !defined (__VMS) && (defined (__cplusplus) || (defined (__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L) /* C99 */) ) 39 # if defined(_AIX) 40 # include <inttypes.h> 41 # else 42 # include <stdint.h> /* intptr_t */ 43 # endif 44 typedef uint8_t BYTE; 45 typedef uint8_t U8; 46 typedef int8_t S8; 47 typedef uint16_t U16; 48 typedef int16_t S16; 49 typedef uint32_t U32; 50 typedef int32_t S32; 51 typedef uint64_t U64; 52 typedef int64_t S64; 53 #else 54 # include <limits.h> 55 #if CHAR_BIT != 8 56 # error "this implementation requires char to be exactly 8-bit type" 57 #endif 58 typedef unsigned char BYTE; 59 typedef unsigned char U8; 60 typedef signed char S8; 61 #if USHRT_MAX != 65535 62 # error "this implementation requires short to be exactly 16-bit type" 63 #endif 64 typedef unsigned short U16; 65 typedef signed short S16; 66 #if UINT_MAX != 4294967295 67 # error "this implementation requires int to be exactly 32-bit type" 68 #endif 69 typedef unsigned int U32; 70 typedef signed int S32; 71 /* note : there are no limits defined for long long type in C90. 72 * limits exist in C99, however, in such case, <stdint.h> is preferred */ 73 typedef unsigned long long U64; 74 typedef signed long long S64; 75 #endif 76 77 78 /*-************************************************************** 79 * Memory I/O API 80 *****************************************************************/ 81 /*=== Static platform detection ===*/ 82 MEM_STATIC unsigned MEM_32bits(void); 83 MEM_STATIC unsigned MEM_64bits(void); 84 MEM_STATIC unsigned MEM_isLittleEndian(void); 85 86 /*=== Native unaligned read/write ===*/ 87 MEM_STATIC U16 MEM_read16(const void* memPtr); 88 MEM_STATIC U32 MEM_read32(const void* memPtr); 89 MEM_STATIC U64 MEM_read64(const void* memPtr); 90 MEM_STATIC size_t MEM_readST(const void* memPtr); 91 92 MEM_STATIC void MEM_write16(void* memPtr, U16 value); 93 MEM_STATIC void MEM_write32(void* memPtr, U32 value); 94 MEM_STATIC void MEM_write64(void* memPtr, U64 value); 95 96 /*=== Little endian unaligned read/write ===*/ 97 MEM_STATIC U16 MEM_readLE16(const void* memPtr); 98 MEM_STATIC U32 MEM_readLE24(const void* memPtr); 99 MEM_STATIC U32 MEM_readLE32(const void* memPtr); 100 MEM_STATIC U64 MEM_readLE64(const void* memPtr); 101 MEM_STATIC size_t MEM_readLEST(const void* memPtr); 102 103 MEM_STATIC void MEM_writeLE16(void* memPtr, U16 val); 104 MEM_STATIC void MEM_writeLE24(void* memPtr, U32 val); 105 MEM_STATIC void MEM_writeLE32(void* memPtr, U32 val32); 106 MEM_STATIC void MEM_writeLE64(void* memPtr, U64 val64); 107 MEM_STATIC void MEM_writeLEST(void* memPtr, size_t val); 108 109 /*=== Big endian unaligned read/write ===*/ 110 MEM_STATIC U32 MEM_readBE32(const void* memPtr); 111 MEM_STATIC U64 MEM_readBE64(const void* memPtr); 112 MEM_STATIC size_t MEM_readBEST(const void* memPtr); 113 114 MEM_STATIC void MEM_writeBE32(void* memPtr, U32 val32); 115 MEM_STATIC void MEM_writeBE64(void* memPtr, U64 val64); 116 MEM_STATIC void MEM_writeBEST(void* memPtr, size_t val); 117 118 /*=== Byteswap ===*/ 119 MEM_STATIC U32 MEM_swap32(U32 in); 120 MEM_STATIC U64 MEM_swap64(U64 in); 121 MEM_STATIC size_t MEM_swapST(size_t in); 122 123 124 /*-************************************************************** 125 * Memory I/O Implementation 126 *****************************************************************/ 127 /* MEM_FORCE_MEMORY_ACCESS : For accessing unaligned memory: 128 * Method 0 : always use `memcpy()`. Safe and portable. 129 * Method 1 : Use compiler extension to set unaligned access. 130 * Method 2 : direct access. This method is portable but violate C standard. 131 * It can generate buggy code on targets depending on alignment. 132 * Default : method 1 if supported, else method 0 133 */ 134 #ifndef MEM_FORCE_MEMORY_ACCESS /* can be defined externally, on command line for example */ 135 # ifdef __GNUC__ 136 # define MEM_FORCE_MEMORY_ACCESS 1 137 # endif 138 #endif 139 140 MEM_STATIC unsigned MEM_32bits(void) { return sizeof(size_t)==4; } 141 MEM_STATIC unsigned MEM_64bits(void) { return sizeof(size_t)==8; } 142 143 MEM_STATIC unsigned MEM_isLittleEndian(void) 144 { 145 #if defined(__BYTE_ORDER__) && defined(__ORDER_LITTLE_ENDIAN__) && (__BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__) 146 return 1; 147 #elif defined(__BYTE_ORDER__) && defined(__ORDER_BIG_ENDIAN__) && (__BYTE_ORDER__ == __ORDER_BIG_ENDIAN__) 148 return 0; 149 #elif defined(__clang__) && __LITTLE_ENDIAN__ 150 return 1; 151 #elif defined(__clang__) && __BIG_ENDIAN__ 152 return 0; 153 #elif defined(_MSC_VER) && (_M_AMD64 || _M_IX86) 154 return 1; 155 #elif defined(__DMC__) && defined(_M_IX86) 156 return 1; 157 #else 158 const union { U32 u; BYTE c[4]; } one = { 1 }; /* don't use static : performance detrimental */ 159 return one.c[0]; 160 #endif 161 } 162 163 #if defined(MEM_FORCE_MEMORY_ACCESS) && (MEM_FORCE_MEMORY_ACCESS==2) 164 165 /* violates C standard, by lying on structure alignment. 166 Only use if no other choice to achieve best performance on target platform */ 167 MEM_STATIC U16 MEM_read16(const void* memPtr) { return *(const U16*) memPtr; } 168 MEM_STATIC U32 MEM_read32(const void* memPtr) { return *(const U32*) memPtr; } 169 MEM_STATIC U64 MEM_read64(const void* memPtr) { return *(const U64*) memPtr; } 170 MEM_STATIC size_t MEM_readST(const void* memPtr) { return *(const size_t*) memPtr; } 171 172 MEM_STATIC void MEM_write16(void* memPtr, U16 value) { *(U16*)memPtr = value; } 173 MEM_STATIC void MEM_write32(void* memPtr, U32 value) { *(U32*)memPtr = value; } 174 MEM_STATIC void MEM_write64(void* memPtr, U64 value) { *(U64*)memPtr = value; } 175 176 #elif defined(MEM_FORCE_MEMORY_ACCESS) && (MEM_FORCE_MEMORY_ACCESS==1) 177 178 typedef __attribute__((aligned(1))) U16 unalign16; 179 typedef __attribute__((aligned(1))) U32 unalign32; 180 typedef __attribute__((aligned(1))) U64 unalign64; 181 typedef __attribute__((aligned(1))) size_t unalignArch; 182 183 MEM_STATIC U16 MEM_read16(const void* ptr) { return *(const unalign16*)ptr; } 184 MEM_STATIC U32 MEM_read32(const void* ptr) { return *(const unalign32*)ptr; } 185 MEM_STATIC U64 MEM_read64(const void* ptr) { return *(const unalign64*)ptr; } 186 MEM_STATIC size_t MEM_readST(const void* ptr) { return *(const unalignArch*)ptr; } 187 188 MEM_STATIC void MEM_write16(void* memPtr, U16 value) { *(unalign16*)memPtr = value; } 189 MEM_STATIC void MEM_write32(void* memPtr, U32 value) { *(unalign32*)memPtr = value; } 190 MEM_STATIC void MEM_write64(void* memPtr, U64 value) { *(unalign64*)memPtr = value; } 191 192 #else 193 194 /* default method, safe and standard. 195 can sometimes prove slower */ 196 197 MEM_STATIC U16 MEM_read16(const void* memPtr) 198 { 199 U16 val; ZSTD_memcpy(&val, memPtr, sizeof(val)); return val; 200 } 201 202 MEM_STATIC U32 MEM_read32(const void* memPtr) 203 { 204 U32 val; ZSTD_memcpy(&val, memPtr, sizeof(val)); return val; 205 } 206 207 MEM_STATIC U64 MEM_read64(const void* memPtr) 208 { 209 U64 val; ZSTD_memcpy(&val, memPtr, sizeof(val)); return val; 210 } 211 212 MEM_STATIC size_t MEM_readST(const void* memPtr) 213 { 214 size_t val; ZSTD_memcpy(&val, memPtr, sizeof(val)); return val; 215 } 216 217 MEM_STATIC void MEM_write16(void* memPtr, U16 value) 218 { 219 ZSTD_memcpy(memPtr, &value, sizeof(value)); 220 } 221 222 MEM_STATIC void MEM_write32(void* memPtr, U32 value) 223 { 224 ZSTD_memcpy(memPtr, &value, sizeof(value)); 225 } 226 227 MEM_STATIC void MEM_write64(void* memPtr, U64 value) 228 { 229 ZSTD_memcpy(memPtr, &value, sizeof(value)); 230 } 231 232 #endif /* MEM_FORCE_MEMORY_ACCESS */ 233 234 MEM_STATIC U32 MEM_swap32_fallback(U32 in) 235 { 236 return ((in << 24) & 0xff000000 ) | 237 ((in << 8) & 0x00ff0000 ) | 238 ((in >> 8) & 0x0000ff00 ) | 239 ((in >> 24) & 0x000000ff ); 240 } 241 242 MEM_STATIC U32 MEM_swap32(U32 in) 243 { 244 #if defined(_MSC_VER) /* Visual Studio */ 245 return _byteswap_ulong(in); 246 #elif (defined (__GNUC__) && (__GNUC__ * 100 + __GNUC_MINOR__ >= 403)) \ 247 || (defined(__clang__) && __has_builtin(__builtin_bswap32)) 248 return __builtin_bswap32(in); 249 #else 250 return MEM_swap32_fallback(in); 251 #endif 252 } 253 254 MEM_STATIC U64 MEM_swap64_fallback(U64 in) 255 { 256 return ((in << 56) & 0xff00000000000000ULL) | 257 ((in << 40) & 0x00ff000000000000ULL) | 258 ((in << 24) & 0x0000ff0000000000ULL) | 259 ((in << 8) & 0x000000ff00000000ULL) | 260 ((in >> 8) & 0x00000000ff000000ULL) | 261 ((in >> 24) & 0x0000000000ff0000ULL) | 262 ((in >> 40) & 0x000000000000ff00ULL) | 263 ((in >> 56) & 0x00000000000000ffULL); 264 } 265 266 MEM_STATIC U64 MEM_swap64(U64 in) 267 { 268 #if defined(_MSC_VER) /* Visual Studio */ 269 return _byteswap_uint64(in); 270 #elif (defined (__GNUC__) && (__GNUC__ * 100 + __GNUC_MINOR__ >= 403)) \ 271 || (defined(__clang__) && __has_builtin(__builtin_bswap64)) 272 return __builtin_bswap64(in); 273 #else 274 return MEM_swap64_fallback(in); 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 (U32)MEM_readLE16(memPtr) + ((U32)(((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