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 /*-**************************************************************
37 *****************************************************************/
38 #if !defined (__VMS) && (defined (__cplusplus) || (defined (__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L) /* C99 */) )
40 # include <inttypes.h>
42 # include <stdint.h> /* intptr_t */
56 # error "this implementation requires char to be exactly 8-bit type"
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"
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"
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;
78 /*-**************************************************************
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);
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);
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);
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);
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);
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);
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);
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);
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
134 #ifndef MEM_FORCE_MEMORY_ACCESS /* can be defined externally, on command line for example */
136 # define MEM_FORCE_MEMORY_ACCESS 1
140 MEM_STATIC unsigned MEM_32bits(void) { return sizeof(size_t)==4; }
141 MEM_STATIC unsigned MEM_64bits(void) { return sizeof(size_t)==8; }
143 MEM_STATIC unsigned MEM_isLittleEndian(void)
145 #if defined(__BYTE_ORDER__) && defined(__ORDER_LITTLE_ENDIAN__) && (__BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__)
147 #elif defined(__BYTE_ORDER__) && defined(__ORDER_BIG_ENDIAN__) && (__BYTE_ORDER__ == __ORDER_BIG_ENDIAN__)
149 #elif defined(__clang__) && __LITTLE_ENDIAN__
151 #elif defined(__clang__) && __BIG_ENDIAN__
153 #elif defined(_MSC_VER) && (_M_AMD64 || _M_IX86)
155 #elif defined(__DMC__) && defined(_M_IX86)
158 const union { U32 u; BYTE c[4]; } one = { 1 }; /* don't use static : performance detrimental */
163 #if defined(MEM_FORCE_MEMORY_ACCESS) && (MEM_FORCE_MEMORY_ACCESS==2)
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; }
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; }
176 #elif defined(MEM_FORCE_MEMORY_ACCESS) && (MEM_FORCE_MEMORY_ACCESS==1)
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;
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; }
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; }
194 /* default method, safe and standard.
195 can sometimes prove slower */
197 MEM_STATIC U16 MEM_read16(const void* memPtr)
199 U16 val; ZSTD_memcpy(&val, memPtr, sizeof(val)); return val;
202 MEM_STATIC U32 MEM_read32(const void* memPtr)
204 U32 val; ZSTD_memcpy(&val, memPtr, sizeof(val)); return val;
207 MEM_STATIC U64 MEM_read64(const void* memPtr)
209 U64 val; ZSTD_memcpy(&val, memPtr, sizeof(val)); return val;
212 MEM_STATIC size_t MEM_readST(const void* memPtr)
214 size_t val; ZSTD_memcpy(&val, memPtr, sizeof(val)); return val;
217 MEM_STATIC void MEM_write16(void* memPtr, U16 value)
219 ZSTD_memcpy(memPtr, &value, sizeof(value));
222 MEM_STATIC void MEM_write32(void* memPtr, U32 value)
224 ZSTD_memcpy(memPtr, &value, sizeof(value));
227 MEM_STATIC void MEM_write64(void* memPtr, U64 value)
229 ZSTD_memcpy(memPtr, &value, sizeof(value));
232 #endif /* MEM_FORCE_MEMORY_ACCESS */
234 MEM_STATIC U32 MEM_swap32_fallback(U32 in)
236 return ((in << 24) & 0xff000000 ) |
237 ((in << 8) & 0x00ff0000 ) |
238 ((in >> 8) & 0x0000ff00 ) |
239 ((in >> 24) & 0x000000ff );
242 MEM_STATIC U32 MEM_swap32(U32 in)
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);
250 return MEM_swap32_fallback(in);
254 MEM_STATIC U64 MEM_swap64_fallback(U64 in)
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);
266 MEM_STATIC U64 MEM_swap64(U64 in)
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);
274 return MEM_swap64_fallback(in);
278 MEM_STATIC size_t MEM_swapST(size_t in)
281 return (size_t)MEM_swap32((U32)in);
283 return (size_t)MEM_swap64((U64)in);
286 /*=== Little endian r/w ===*/
288 MEM_STATIC U16 MEM_readLE16(const void* memPtr)
290 if (MEM_isLittleEndian())
291 return MEM_read16(memPtr);
293 const BYTE* p = (const BYTE*)memPtr;
294 return (U16)(p[0] + (p[1]<<8));
298 MEM_STATIC void MEM_writeLE16(void* memPtr, U16 val)
300 if (MEM_isLittleEndian()) {
301 MEM_write16(memPtr, val);
303 BYTE* p = (BYTE*)memPtr;
305 p[1] = (BYTE)(val>>8);
309 MEM_STATIC U32 MEM_readLE24(const void* memPtr)
311 return (U32)MEM_readLE16(memPtr) + ((U32)(((const BYTE*)memPtr)[2]) << 16);
314 MEM_STATIC void MEM_writeLE24(void* memPtr, U32 val)
316 MEM_writeLE16(memPtr, (U16)val);
317 ((BYTE*)memPtr)[2] = (BYTE)(val>>16);
320 MEM_STATIC U32 MEM_readLE32(const void* memPtr)
322 if (MEM_isLittleEndian())
323 return MEM_read32(memPtr);
325 return MEM_swap32(MEM_read32(memPtr));
328 MEM_STATIC void MEM_writeLE32(void* memPtr, U32 val32)
330 if (MEM_isLittleEndian())
331 MEM_write32(memPtr, val32);
333 MEM_write32(memPtr, MEM_swap32(val32));
336 MEM_STATIC U64 MEM_readLE64(const void* memPtr)
338 if (MEM_isLittleEndian())
339 return MEM_read64(memPtr);
341 return MEM_swap64(MEM_read64(memPtr));
344 MEM_STATIC void MEM_writeLE64(void* memPtr, U64 val64)
346 if (MEM_isLittleEndian())
347 MEM_write64(memPtr, val64);
349 MEM_write64(memPtr, MEM_swap64(val64));
352 MEM_STATIC size_t MEM_readLEST(const void* memPtr)
355 return (size_t)MEM_readLE32(memPtr);
357 return (size_t)MEM_readLE64(memPtr);
360 MEM_STATIC void MEM_writeLEST(void* memPtr, size_t val)
363 MEM_writeLE32(memPtr, (U32)val);
365 MEM_writeLE64(memPtr, (U64)val);
368 /*=== Big endian r/w ===*/
370 MEM_STATIC U32 MEM_readBE32(const void* memPtr)
372 if (MEM_isLittleEndian())
373 return MEM_swap32(MEM_read32(memPtr));
375 return MEM_read32(memPtr);
378 MEM_STATIC void MEM_writeBE32(void* memPtr, U32 val32)
380 if (MEM_isLittleEndian())
381 MEM_write32(memPtr, MEM_swap32(val32));
383 MEM_write32(memPtr, val32);
386 MEM_STATIC U64 MEM_readBE64(const void* memPtr)
388 if (MEM_isLittleEndian())
389 return MEM_swap64(MEM_read64(memPtr));
391 return MEM_read64(memPtr);
394 MEM_STATIC void MEM_writeBE64(void* memPtr, U64 val64)
396 if (MEM_isLittleEndian())
397 MEM_write64(memPtr, MEM_swap64(val64));
399 MEM_write64(memPtr, val64);
402 MEM_STATIC size_t MEM_readBEST(const void* memPtr)
405 return (size_t)MEM_readBE32(memPtr);
407 return (size_t)MEM_readBE64(memPtr);
410 MEM_STATIC void MEM_writeBEST(void* memPtr, size_t val)
413 MEM_writeBE32(memPtr, (U32)val);
415 MEM_writeBE64(memPtr, (U64)val);
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)); }
422 #if defined (__cplusplus)
426 #endif /* MEM_H_MODULE */