2 * Copyright (c) Meta Platforms, Inc. and affiliates.
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.
14 #if defined (__cplusplus)
18 /*-****************************************
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 */
27 /*-****************************************
29 ******************************************/
30 #if defined(_MSC_VER) /* Visual Studio */
31 # include <stdlib.h> /* _byteswap_ulong */
32 # include <intrin.h> /* _byteswap_* */
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
41 # define MEM_STATIC static /* this version may generate warnings for unused static functions; disable the relevant warning */
44 /*-**************************************************************
46 *****************************************************************/
47 #if !defined (__VMS) && (defined (__cplusplus) || (defined (__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L) /* C99 */) )
49 # include <inttypes.h>
51 # include <stdint.h> /* intptr_t */
65 # error "this implementation requires char to be exactly 8-bit type"
67 typedef unsigned char BYTE;
68 typedef unsigned char U8;
69 typedef signed char S8;
70 #if USHRT_MAX != 65535
71 # error "this implementation requires short to be exactly 16-bit type"
73 typedef unsigned short U16;
74 typedef signed short S16;
75 #if UINT_MAX != 4294967295
76 # error "this implementation requires int to be exactly 32-bit type"
78 typedef unsigned int U32;
79 typedef signed int S32;
80 /* note : there are no limits defined for long long type in C90.
81 * limits exist in C99, however, in such case, <stdint.h> is preferred */
82 typedef unsigned long long U64;
83 typedef signed long long S64;
87 /*-**************************************************************
89 *****************************************************************/
90 /*=== Static platform detection ===*/
91 MEM_STATIC unsigned MEM_32bits(void);
92 MEM_STATIC unsigned MEM_64bits(void);
93 MEM_STATIC unsigned MEM_isLittleEndian(void);
95 /*=== Native unaligned read/write ===*/
96 MEM_STATIC U16 MEM_read16(const void* memPtr);
97 MEM_STATIC U32 MEM_read32(const void* memPtr);
98 MEM_STATIC U64 MEM_read64(const void* memPtr);
99 MEM_STATIC size_t MEM_readST(const void* memPtr);
101 MEM_STATIC void MEM_write16(void* memPtr, U16 value);
102 MEM_STATIC void MEM_write32(void* memPtr, U32 value);
103 MEM_STATIC void MEM_write64(void* memPtr, U64 value);
105 /*=== Little endian unaligned read/write ===*/
106 MEM_STATIC U16 MEM_readLE16(const void* memPtr);
107 MEM_STATIC U32 MEM_readLE24(const void* memPtr);
108 MEM_STATIC U32 MEM_readLE32(const void* memPtr);
109 MEM_STATIC U64 MEM_readLE64(const void* memPtr);
110 MEM_STATIC size_t MEM_readLEST(const void* memPtr);
112 MEM_STATIC void MEM_writeLE16(void* memPtr, U16 val);
113 MEM_STATIC void MEM_writeLE24(void* memPtr, U32 val);
114 MEM_STATIC void MEM_writeLE32(void* memPtr, U32 val32);
115 MEM_STATIC void MEM_writeLE64(void* memPtr, U64 val64);
116 MEM_STATIC void MEM_writeLEST(void* memPtr, size_t val);
118 /*=== Big endian unaligned read/write ===*/
119 MEM_STATIC U32 MEM_readBE32(const void* memPtr);
120 MEM_STATIC U64 MEM_readBE64(const void* memPtr);
121 MEM_STATIC size_t MEM_readBEST(const void* memPtr);
123 MEM_STATIC void MEM_writeBE32(void* memPtr, U32 val32);
124 MEM_STATIC void MEM_writeBE64(void* memPtr, U64 val64);
125 MEM_STATIC void MEM_writeBEST(void* memPtr, size_t val);
128 MEM_STATIC U32 MEM_swap32(U32 in);
129 MEM_STATIC U64 MEM_swap64(U64 in);
130 MEM_STATIC size_t MEM_swapST(size_t in);
133 /*-**************************************************************
134 * Memory I/O Implementation
135 *****************************************************************/
136 /* MEM_FORCE_MEMORY_ACCESS : For accessing unaligned memory:
137 * Method 0 : always use `memcpy()`. Safe and portable.
138 * Method 1 : Use compiler extension to set unaligned access.
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 * Default : method 1 if supported, else method 0
143 #ifndef MEM_FORCE_MEMORY_ACCESS /* can be defined externally, on command line for example */
145 # define MEM_FORCE_MEMORY_ACCESS 1
149 MEM_STATIC unsigned MEM_32bits(void) { return sizeof(size_t)==4; }
150 MEM_STATIC unsigned MEM_64bits(void) { return sizeof(size_t)==8; }
152 MEM_STATIC unsigned MEM_isLittleEndian(void)
154 #if defined(__BYTE_ORDER__) && defined(__ORDER_LITTLE_ENDIAN__) && (__BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__)
156 #elif defined(__BYTE_ORDER__) && defined(__ORDER_BIG_ENDIAN__) && (__BYTE_ORDER__ == __ORDER_BIG_ENDIAN__)
158 #elif defined(__clang__) && __LITTLE_ENDIAN__
160 #elif defined(__clang__) && __BIG_ENDIAN__
162 #elif defined(_MSC_VER) && (_M_AMD64 || _M_IX86)
164 #elif defined(__DMC__) && defined(_M_IX86)
167 const union { U32 u; BYTE c[4]; } one = { 1 }; /* don't use static : performance detrimental */
172 #if defined(MEM_FORCE_MEMORY_ACCESS) && (MEM_FORCE_MEMORY_ACCESS==2)
174 /* violates C standard, by lying on structure alignment.
175 Only use if no other choice to achieve best performance on target platform */
176 MEM_STATIC U16 MEM_read16(const void* memPtr) { return *(const U16*) memPtr; }
177 MEM_STATIC U32 MEM_read32(const void* memPtr) { return *(const U32*) memPtr; }
178 MEM_STATIC U64 MEM_read64(const void* memPtr) { return *(const U64*) memPtr; }
179 MEM_STATIC size_t MEM_readST(const void* memPtr) { return *(const size_t*) memPtr; }
181 MEM_STATIC void MEM_write16(void* memPtr, U16 value) { *(U16*)memPtr = value; }
182 MEM_STATIC void MEM_write32(void* memPtr, U32 value) { *(U32*)memPtr = value; }
183 MEM_STATIC void MEM_write64(void* memPtr, U64 value) { *(U64*)memPtr = value; }
185 #elif defined(MEM_FORCE_MEMORY_ACCESS) && (MEM_FORCE_MEMORY_ACCESS==1)
187 typedef __attribute__((aligned(1))) U16 unalign16;
188 typedef __attribute__((aligned(1))) U32 unalign32;
189 typedef __attribute__((aligned(1))) U64 unalign64;
190 typedef __attribute__((aligned(1))) size_t unalignArch;
192 MEM_STATIC U16 MEM_read16(const void* ptr) { return *(const unalign16*)ptr; }
193 MEM_STATIC U32 MEM_read32(const void* ptr) { return *(const unalign32*)ptr; }
194 MEM_STATIC U64 MEM_read64(const void* ptr) { return *(const unalign64*)ptr; }
195 MEM_STATIC size_t MEM_readST(const void* ptr) { return *(const unalignArch*)ptr; }
197 MEM_STATIC void MEM_write16(void* memPtr, U16 value) { *(unalign16*)memPtr = value; }
198 MEM_STATIC void MEM_write32(void* memPtr, U32 value) { *(unalign32*)memPtr = value; }
199 MEM_STATIC void MEM_write64(void* memPtr, U64 value) { *(unalign64*)memPtr = value; }
203 /* default method, safe and standard.
204 can sometimes prove slower */
206 MEM_STATIC U16 MEM_read16(const void* memPtr)
208 U16 val; ZSTD_memcpy(&val, memPtr, sizeof(val)); return val;
211 MEM_STATIC U32 MEM_read32(const void* memPtr)
213 U32 val; ZSTD_memcpy(&val, memPtr, sizeof(val)); return val;
216 MEM_STATIC U64 MEM_read64(const void* memPtr)
218 U64 val; ZSTD_memcpy(&val, memPtr, sizeof(val)); return val;
221 MEM_STATIC size_t MEM_readST(const void* memPtr)
223 size_t val; ZSTD_memcpy(&val, memPtr, sizeof(val)); return val;
226 MEM_STATIC void MEM_write16(void* memPtr, U16 value)
228 ZSTD_memcpy(memPtr, &value, sizeof(value));
231 MEM_STATIC void MEM_write32(void* memPtr, U32 value)
233 ZSTD_memcpy(memPtr, &value, sizeof(value));
236 MEM_STATIC void MEM_write64(void* memPtr, U64 value)
238 ZSTD_memcpy(memPtr, &value, sizeof(value));
241 #endif /* MEM_FORCE_MEMORY_ACCESS */
243 MEM_STATIC U32 MEM_swap32_fallback(U32 in)
245 return ((in << 24) & 0xff000000 ) |
246 ((in << 8) & 0x00ff0000 ) |
247 ((in >> 8) & 0x0000ff00 ) |
248 ((in >> 24) & 0x000000ff );
251 MEM_STATIC U32 MEM_swap32(U32 in)
253 #if defined(_MSC_VER) /* Visual Studio */
254 return _byteswap_ulong(in);
255 #elif (defined (__GNUC__) && (__GNUC__ * 100 + __GNUC_MINOR__ >= 403)) \
256 || (defined(__clang__) && __has_builtin(__builtin_bswap32))
257 return __builtin_bswap32(in);
259 return MEM_swap32_fallback(in);
263 MEM_STATIC U64 MEM_swap64_fallback(U64 in)
265 return ((in << 56) & 0xff00000000000000ULL) |
266 ((in << 40) & 0x00ff000000000000ULL) |
267 ((in << 24) & 0x0000ff0000000000ULL) |
268 ((in << 8) & 0x000000ff00000000ULL) |
269 ((in >> 8) & 0x00000000ff000000ULL) |
270 ((in >> 24) & 0x0000000000ff0000ULL) |
271 ((in >> 40) & 0x000000000000ff00ULL) |
272 ((in >> 56) & 0x00000000000000ffULL);
275 MEM_STATIC U64 MEM_swap64(U64 in)
277 #if defined(_MSC_VER) /* Visual Studio */
278 return _byteswap_uint64(in);
279 #elif (defined (__GNUC__) && (__GNUC__ * 100 + __GNUC_MINOR__ >= 403)) \
280 || (defined(__clang__) && __has_builtin(__builtin_bswap64))
281 return __builtin_bswap64(in);
283 return MEM_swap64_fallback(in);
287 MEM_STATIC size_t MEM_swapST(size_t in)
290 return (size_t)MEM_swap32((U32)in);
292 return (size_t)MEM_swap64((U64)in);
295 /*=== Little endian r/w ===*/
297 MEM_STATIC U16 MEM_readLE16(const void* memPtr)
299 if (MEM_isLittleEndian())
300 return MEM_read16(memPtr);
302 const BYTE* p = (const BYTE*)memPtr;
303 return (U16)(p[0] + (p[1]<<8));
307 MEM_STATIC void MEM_writeLE16(void* memPtr, U16 val)
309 if (MEM_isLittleEndian()) {
310 MEM_write16(memPtr, val);
312 BYTE* p = (BYTE*)memPtr;
314 p[1] = (BYTE)(val>>8);
318 MEM_STATIC U32 MEM_readLE24(const void* memPtr)
320 return (U32)MEM_readLE16(memPtr) + ((U32)(((const BYTE*)memPtr)[2]) << 16);
323 MEM_STATIC void MEM_writeLE24(void* memPtr, U32 val)
325 MEM_writeLE16(memPtr, (U16)val);
326 ((BYTE*)memPtr)[2] = (BYTE)(val>>16);
329 MEM_STATIC U32 MEM_readLE32(const void* memPtr)
331 if (MEM_isLittleEndian())
332 return MEM_read32(memPtr);
334 return MEM_swap32(MEM_read32(memPtr));
337 MEM_STATIC void MEM_writeLE32(void* memPtr, U32 val32)
339 if (MEM_isLittleEndian())
340 MEM_write32(memPtr, val32);
342 MEM_write32(memPtr, MEM_swap32(val32));
345 MEM_STATIC U64 MEM_readLE64(const void* memPtr)
347 if (MEM_isLittleEndian())
348 return MEM_read64(memPtr);
350 return MEM_swap64(MEM_read64(memPtr));
353 MEM_STATIC void MEM_writeLE64(void* memPtr, U64 val64)
355 if (MEM_isLittleEndian())
356 MEM_write64(memPtr, val64);
358 MEM_write64(memPtr, MEM_swap64(val64));
361 MEM_STATIC size_t MEM_readLEST(const void* memPtr)
364 return (size_t)MEM_readLE32(memPtr);
366 return (size_t)MEM_readLE64(memPtr);
369 MEM_STATIC void MEM_writeLEST(void* memPtr, size_t val)
372 MEM_writeLE32(memPtr, (U32)val);
374 MEM_writeLE64(memPtr, (U64)val);
377 /*=== Big endian r/w ===*/
379 MEM_STATIC U32 MEM_readBE32(const void* memPtr)
381 if (MEM_isLittleEndian())
382 return MEM_swap32(MEM_read32(memPtr));
384 return MEM_read32(memPtr);
387 MEM_STATIC void MEM_writeBE32(void* memPtr, U32 val32)
389 if (MEM_isLittleEndian())
390 MEM_write32(memPtr, MEM_swap32(val32));
392 MEM_write32(memPtr, val32);
395 MEM_STATIC U64 MEM_readBE64(const void* memPtr)
397 if (MEM_isLittleEndian())
398 return MEM_swap64(MEM_read64(memPtr));
400 return MEM_read64(memPtr);
403 MEM_STATIC void MEM_writeBE64(void* memPtr, U64 val64)
405 if (MEM_isLittleEndian())
406 MEM_write64(memPtr, MEM_swap64(val64));
408 MEM_write64(memPtr, val64);
411 MEM_STATIC size_t MEM_readBEST(const void* memPtr)
414 return (size_t)MEM_readBE32(memPtr);
416 return (size_t)MEM_readBE64(memPtr);
419 MEM_STATIC void MEM_writeBEST(void* memPtr, size_t val)
422 MEM_writeBE32(memPtr, (U32)val);
424 MEM_writeBE64(memPtr, (U64)val);
427 /* code only tested on 32 and 64 bits systems */
428 MEM_STATIC void MEM_check(void) { DEBUG_STATIC_ASSERT((sizeof(size_t)==4) || (sizeof(size_t)==8)); }
431 #if defined (__cplusplus)
435 #endif /* MEM_H_MODULE */