1 /*
2 * Copyright (c) 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 uint8_t U8;
55 typedef int8_t S8;
56 typedef uint16_t U16;
57 typedef int16_t S16;
58 typedef uint32_t U32;
59 typedef int32_t S32;
60 typedef uint64_t U64;
61 typedef int64_t S64;
62 #else
63 # include <limits.h>
64 #if CHAR_BIT != 8
65 # error "this implementation requires char to be exactly 8-bit type"
66 #endif
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"
72 #endif
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"
77 #endif
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;
84 #endif
85
86
87 /*-**************************************************************
88 * Memory I/O API
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);
94
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);
100
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);
104
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);
111
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);
117
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);
122
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);
126
127 /*=== Byteswap ===*/
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);
131
132
133 /*-**************************************************************
134 * Memory I/O Implementation
135 *****************************************************************/
136 /* MEM_FORCE_MEMORY_ACCESS :
137 * By default, access to unaligned memory is controlled by `memcpy()`, which is safe and portable.
138 * Unfortunately, on some target/compiler combinations, the generated assembly is sub-optimal.
139 * The below switch allow to select different access method for improved performance.
140 * Method 0 (default) : use `memcpy()`. Safe and portable.
141 * Method 1 : `__packed` statement. It depends on compiler extension (i.e., not portable).
142 * This method is safe if your compiler supports it, and *generally* as fast or faster than `memcpy`.
143 * Method 2 : direct access. This method is portable but violate C standard.
144 * It can generate buggy code on targets depending on alignment.
145 * In some circumstances, it's the only known way to get the most performance (i.e. GCC + ARMv6)
146 * See http://fastcompression.blogspot.fr/2015/08/accessing-unaligned-memory.html for details.
147 * Prefer these methods in priority order (0 > 1 > 2)
148 */
149 #ifndef MEM_FORCE_MEMORY_ACCESS /* can be defined externally, on command line for example */
150 # if defined(__INTEL_COMPILER) || defined(__GNUC__) || defined(__ICCARM__)
151 # define MEM_FORCE_MEMORY_ACCESS 1
152 # endif
153 #endif
154
MEM_32bits(void)155 MEM_STATIC unsigned MEM_32bits(void) { return sizeof(size_t)==4; }
MEM_64bits(void)156 MEM_STATIC unsigned MEM_64bits(void) { return sizeof(size_t)==8; }
157
MEM_isLittleEndian(void)158 MEM_STATIC unsigned MEM_isLittleEndian(void)
159 {
160 #if defined(__BYTE_ORDER__) && defined(__ORDER_LITTLE_ENDIAN__) && (__BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__)
161 return 1;
162 #elif defined(__BYTE_ORDER__) && defined(__ORDER_BIG_ENDIAN__) && (__BYTE_ORDER__ == __ORDER_BIG_ENDIAN__)
163 return 0;
164 #elif defined(__clang__) && __LITTLE_ENDIAN__
165 return 1;
166 #elif defined(__clang__) && __BIG_ENDIAN__
167 return 0;
168 #elif defined(_MSC_VER) && (_M_AMD64 || _M_IX86)
169 return 1;
170 #elif defined(__DMC__) && defined(_M_IX86)
171 return 1;
172 #else
173 const union { U32 u; BYTE c[4]; } one = { 1 }; /* don't use static : performance detrimental */
174 return one.c[0];
175 #endif
176 }
177
178 #if defined(MEM_FORCE_MEMORY_ACCESS) && (MEM_FORCE_MEMORY_ACCESS==2)
179
180 /* violates C standard, by lying on structure alignment.
181 Only use if no other choice to achieve best performance on target platform */
MEM_read16(const void * memPtr)182 MEM_STATIC U16 MEM_read16(const void* memPtr) { return *(const U16*) memPtr; }
MEM_read32(const void * memPtr)183 MEM_STATIC U32 MEM_read32(const void* memPtr) { return *(const U32*) memPtr; }
MEM_read64(const void * memPtr)184 MEM_STATIC U64 MEM_read64(const void* memPtr) { return *(const U64*) memPtr; }
MEM_readST(const void * memPtr)185 MEM_STATIC size_t MEM_readST(const void* memPtr) { return *(const size_t*) memPtr; }
186
MEM_write16(void * memPtr,U16 value)187 MEM_STATIC void MEM_write16(void* memPtr, U16 value) { *(U16*)memPtr = value; }
MEM_write32(void * memPtr,U32 value)188 MEM_STATIC void MEM_write32(void* memPtr, U32 value) { *(U32*)memPtr = value; }
MEM_write64(void * memPtr,U64 value)189 MEM_STATIC void MEM_write64(void* memPtr, U64 value) { *(U64*)memPtr = value; }
190
191 #elif defined(MEM_FORCE_MEMORY_ACCESS) && (MEM_FORCE_MEMORY_ACCESS==1)
192
193 /* __pack instructions are safer, but compiler specific, hence potentially problematic for some compilers */
194 /* currently only defined for gcc and icc */
195 #if defined(_MSC_VER) || (defined(__INTEL_COMPILER) && defined(WIN32))
196 __pragma( pack(push, 1) )
197 typedef struct { U16 v; } unalign16;
198 typedef struct { U32 v; } unalign32;
199 typedef struct { U64 v; } unalign64;
200 typedef struct { size_t v; } unalignArch;
__pragma(pack (pop))201 __pragma( pack(pop) )
202 #else
203 typedef struct { U16 v; } __attribute__((packed)) unalign16;
204 typedef struct { U32 v; } __attribute__((packed)) unalign32;
205 typedef struct { U64 v; } __attribute__((packed)) unalign64;
206 typedef struct { size_t v; } __attribute__((packed)) unalignArch;
207 #endif
208
209 MEM_STATIC U16 MEM_read16(const void* ptr) { return ((const unalign16*)ptr)->v; }
MEM_read32(const void * ptr)210 MEM_STATIC U32 MEM_read32(const void* ptr) { return ((const unalign32*)ptr)->v; }
MEM_read64(const void * ptr)211 MEM_STATIC U64 MEM_read64(const void* ptr) { return ((const unalign64*)ptr)->v; }
MEM_readST(const void * ptr)212 MEM_STATIC size_t MEM_readST(const void* ptr) { return ((const unalignArch*)ptr)->v; }
213
MEM_write16(void * memPtr,U16 value)214 MEM_STATIC void MEM_write16(void* memPtr, U16 value) { ((unalign16*)memPtr)->v = value; }
MEM_write32(void * memPtr,U32 value)215 MEM_STATIC void MEM_write32(void* memPtr, U32 value) { ((unalign32*)memPtr)->v = value; }
MEM_write64(void * memPtr,U64 value)216 MEM_STATIC void MEM_write64(void* memPtr, U64 value) { ((unalign64*)memPtr)->v = value; }
217
218 #else
219
220 /* default method, safe and standard.
221 can sometimes prove slower */
222
MEM_read16(const void * memPtr)223 MEM_STATIC U16 MEM_read16(const void* memPtr)
224 {
225 U16 val; ZSTD_memcpy(&val, memPtr, sizeof(val)); return val;
226 }
227
MEM_read32(const void * memPtr)228 MEM_STATIC U32 MEM_read32(const void* memPtr)
229 {
230 U32 val; ZSTD_memcpy(&val, memPtr, sizeof(val)); return val;
231 }
232
MEM_read64(const void * memPtr)233 MEM_STATIC U64 MEM_read64(const void* memPtr)
234 {
235 U64 val; ZSTD_memcpy(&val, memPtr, sizeof(val)); return val;
236 }
237
MEM_readST(const void * memPtr)238 MEM_STATIC size_t MEM_readST(const void* memPtr)
239 {
240 size_t val; ZSTD_memcpy(&val, memPtr, sizeof(val)); return val;
241 }
242
MEM_write16(void * memPtr,U16 value)243 MEM_STATIC void MEM_write16(void* memPtr, U16 value)
244 {
245 ZSTD_memcpy(memPtr, &value, sizeof(value));
246 }
247
MEM_write32(void * memPtr,U32 value)248 MEM_STATIC void MEM_write32(void* memPtr, U32 value)
249 {
250 ZSTD_memcpy(memPtr, &value, sizeof(value));
251 }
252
MEM_write64(void * memPtr,U64 value)253 MEM_STATIC void MEM_write64(void* memPtr, U64 value)
254 {
255 ZSTD_memcpy(memPtr, &value, sizeof(value));
256 }
257
258 #endif /* MEM_FORCE_MEMORY_ACCESS */
259
MEM_swap32(U32 in)260 MEM_STATIC U32 MEM_swap32(U32 in)
261 {
262 #if defined(_MSC_VER) /* Visual Studio */
263 return _byteswap_ulong(in);
264 #elif (defined (__GNUC__) && (__GNUC__ * 100 + __GNUC_MINOR__ >= 403)) \
265 || (defined(__clang__) && __has_builtin(__builtin_bswap32))
266 return __builtin_bswap32(in);
267 #else
268 return ((in << 24) & 0xff000000 ) |
269 ((in << 8) & 0x00ff0000 ) |
270 ((in >> 8) & 0x0000ff00 ) |
271 ((in >> 24) & 0x000000ff );
272 #endif
273 }
274
MEM_swap64(U64 in)275 MEM_STATIC U64 MEM_swap64(U64 in)
276 {
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);
282 #else
283 return ((in << 56) & 0xff00000000000000ULL) |
284 ((in << 40) & 0x00ff000000000000ULL) |
285 ((in << 24) & 0x0000ff0000000000ULL) |
286 ((in << 8) & 0x000000ff00000000ULL) |
287 ((in >> 8) & 0x00000000ff000000ULL) |
288 ((in >> 24) & 0x0000000000ff0000ULL) |
289 ((in >> 40) & 0x000000000000ff00ULL) |
290 ((in >> 56) & 0x00000000000000ffULL);
291 #endif
292 }
293
MEM_swapST(size_t in)294 MEM_STATIC size_t MEM_swapST(size_t in)
295 {
296 if (MEM_32bits())
297 return (size_t)MEM_swap32((U32)in);
298 else
299 return (size_t)MEM_swap64((U64)in);
300 }
301
302 /*=== Little endian r/w ===*/
303
MEM_readLE16(const void * memPtr)304 MEM_STATIC U16 MEM_readLE16(const void* memPtr)
305 {
306 if (MEM_isLittleEndian())
307 return MEM_read16(memPtr);
308 else {
309 const BYTE* p = (const BYTE*)memPtr;
310 return (U16)(p[0] + (p[1]<<8));
311 }
312 }
313
MEM_writeLE16(void * memPtr,U16 val)314 MEM_STATIC void MEM_writeLE16(void* memPtr, U16 val)
315 {
316 if (MEM_isLittleEndian()) {
317 MEM_write16(memPtr, val);
318 } else {
319 BYTE* p = (BYTE*)memPtr;
320 p[0] = (BYTE)val;
321 p[1] = (BYTE)(val>>8);
322 }
323 }
324
MEM_readLE24(const void * memPtr)325 MEM_STATIC U32 MEM_readLE24(const void* memPtr)
326 {
327 return (U32)MEM_readLE16(memPtr) + ((U32)(((const BYTE*)memPtr)[2]) << 16);
328 }
329
MEM_writeLE24(void * memPtr,U32 val)330 MEM_STATIC void MEM_writeLE24(void* memPtr, U32 val)
331 {
332 MEM_writeLE16(memPtr, (U16)val);
333 ((BYTE*)memPtr)[2] = (BYTE)(val>>16);
334 }
335
MEM_readLE32(const void * memPtr)336 MEM_STATIC U32 MEM_readLE32(const void* memPtr)
337 {
338 if (MEM_isLittleEndian())
339 return MEM_read32(memPtr);
340 else
341 return MEM_swap32(MEM_read32(memPtr));
342 }
343
MEM_writeLE32(void * memPtr,U32 val32)344 MEM_STATIC void MEM_writeLE32(void* memPtr, U32 val32)
345 {
346 if (MEM_isLittleEndian())
347 MEM_write32(memPtr, val32);
348 else
349 MEM_write32(memPtr, MEM_swap32(val32));
350 }
351
MEM_readLE64(const void * memPtr)352 MEM_STATIC U64 MEM_readLE64(const void* memPtr)
353 {
354 if (MEM_isLittleEndian())
355 return MEM_read64(memPtr);
356 else
357 return MEM_swap64(MEM_read64(memPtr));
358 }
359
MEM_writeLE64(void * memPtr,U64 val64)360 MEM_STATIC void MEM_writeLE64(void* memPtr, U64 val64)
361 {
362 if (MEM_isLittleEndian())
363 MEM_write64(memPtr, val64);
364 else
365 MEM_write64(memPtr, MEM_swap64(val64));
366 }
367
MEM_readLEST(const void * memPtr)368 MEM_STATIC size_t MEM_readLEST(const void* memPtr)
369 {
370 if (MEM_32bits())
371 return (size_t)MEM_readLE32(memPtr);
372 else
373 return (size_t)MEM_readLE64(memPtr);
374 }
375
MEM_writeLEST(void * memPtr,size_t val)376 MEM_STATIC void MEM_writeLEST(void* memPtr, size_t val)
377 {
378 if (MEM_32bits())
379 MEM_writeLE32(memPtr, (U32)val);
380 else
381 MEM_writeLE64(memPtr, (U64)val);
382 }
383
384 /*=== Big endian r/w ===*/
385
MEM_readBE32(const void * memPtr)386 MEM_STATIC U32 MEM_readBE32(const void* memPtr)
387 {
388 if (MEM_isLittleEndian())
389 return MEM_swap32(MEM_read32(memPtr));
390 else
391 return MEM_read32(memPtr);
392 }
393
MEM_writeBE32(void * memPtr,U32 val32)394 MEM_STATIC void MEM_writeBE32(void* memPtr, U32 val32)
395 {
396 if (MEM_isLittleEndian())
397 MEM_write32(memPtr, MEM_swap32(val32));
398 else
399 MEM_write32(memPtr, val32);
400 }
401
MEM_readBE64(const void * memPtr)402 MEM_STATIC U64 MEM_readBE64(const void* memPtr)
403 {
404 if (MEM_isLittleEndian())
405 return MEM_swap64(MEM_read64(memPtr));
406 else
407 return MEM_read64(memPtr);
408 }
409
MEM_writeBE64(void * memPtr,U64 val64)410 MEM_STATIC void MEM_writeBE64(void* memPtr, U64 val64)
411 {
412 if (MEM_isLittleEndian())
413 MEM_write64(memPtr, MEM_swap64(val64));
414 else
415 MEM_write64(memPtr, val64);
416 }
417
MEM_readBEST(const void * memPtr)418 MEM_STATIC size_t MEM_readBEST(const void* memPtr)
419 {
420 if (MEM_32bits())
421 return (size_t)MEM_readBE32(memPtr);
422 else
423 return (size_t)MEM_readBE64(memPtr);
424 }
425
MEM_writeBEST(void * memPtr,size_t val)426 MEM_STATIC void MEM_writeBEST(void* memPtr, size_t val)
427 {
428 if (MEM_32bits())
429 MEM_writeBE32(memPtr, (U32)val);
430 else
431 MEM_writeBE64(memPtr, (U64)val);
432 }
433
434 /* code only tested on 32 and 64 bits systems */
MEM_check(void)435 MEM_STATIC void MEM_check(void) { DEBUG_STATIC_ASSERT((sizeof(size_t)==4) || (sizeof(size_t)==8)); }
436
437
438 #if defined (__cplusplus)
439 }
440 #endif
441
442 #endif /* MEM_H_MODULE */
443