2 * Copyright (c) 2016-2020, Yann Collet, Facebook, Inc.
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 */
63 # error "this implementation requires char to be exactly 8-bit type"
65 typedef unsigned char BYTE;
66 #if USHRT_MAX != 65535
67 # error "this implementation requires short to be exactly 16-bit type"
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"
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;
83 /*-**************************************************************
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);
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);
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);
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);
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);
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);
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);
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);
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)
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
153 MEM_STATIC unsigned MEM_32bits(void) { return sizeof(size_t)==4; }
154 MEM_STATIC unsigned MEM_64bits(void) { return sizeof(size_t)==8; }
156 MEM_STATIC unsigned MEM_isLittleEndian(void)
158 const union { U32 u; BYTE c[4]; } one = { 1 }; /* don't use static : performance detrimental */
162 #if defined(MEM_FORCE_MEMORY_ACCESS) && (MEM_FORCE_MEMORY_ACCESS==2)
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; }
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; }
175 #elif defined(MEM_FORCE_MEMORY_ACCESS) && (MEM_FORCE_MEMORY_ACCESS==1)
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) )
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;
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; }
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; }
204 /* default method, safe and standard.
205 can sometimes prove slower */
207 MEM_STATIC U16 MEM_read16(const void* memPtr)
209 U16 val; ZSTD_memcpy(&val, memPtr, sizeof(val)); return val;
212 MEM_STATIC U32 MEM_read32(const void* memPtr)
214 U32 val; ZSTD_memcpy(&val, memPtr, sizeof(val)); return val;
217 MEM_STATIC U64 MEM_read64(const void* memPtr)
219 U64 val; ZSTD_memcpy(&val, memPtr, sizeof(val)); return val;
222 MEM_STATIC size_t MEM_readST(const void* memPtr)
224 size_t val; ZSTD_memcpy(&val, memPtr, sizeof(val)); return val;
227 MEM_STATIC void MEM_write16(void* memPtr, U16 value)
229 ZSTD_memcpy(memPtr, &value, sizeof(value));
232 MEM_STATIC void MEM_write32(void* memPtr, U32 value)
234 ZSTD_memcpy(memPtr, &value, sizeof(value));
237 MEM_STATIC void MEM_write64(void* memPtr, U64 value)
239 ZSTD_memcpy(memPtr, &value, sizeof(value));
242 #endif /* MEM_FORCE_MEMORY_ACCESS */
244 MEM_STATIC U32 MEM_swap32(U32 in)
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);
252 return ((in << 24) & 0xff000000 ) |
253 ((in << 8) & 0x00ff0000 ) |
254 ((in >> 8) & 0x0000ff00 ) |
255 ((in >> 24) & 0x000000ff );
259 MEM_STATIC U64 MEM_swap64(U64 in)
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);
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);
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 MEM_readLE16(memPtr) + (((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 */