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 /*-****************************************
15 * Dependencies
16 ******************************************/
17 #include <stddef.h> /* size_t, ptrdiff_t */
18 #include "compiler.h" /* __has_builtin */
19 #include "debug.h" /* DEBUG_STATIC_ASSERT */
20 #include "zstd_deps.h" /* ZSTD_memcpy */
21
22
23 /*-****************************************
24 * Compiler specifics
25 ******************************************/
26 #if defined(_MSC_VER) /* Visual Studio */
27 # include <stdlib.h> /* _byteswap_ulong */
28 # include <intrin.h> /* _byteswap_* */
29 #elif defined(__ICCARM__)
30 # include <intrinsics.h>
31 #endif
32
33 /*-**************************************************************
34 * Basic Types
35 *****************************************************************/
36 #if !defined (__VMS) && (defined (__cplusplus) || (defined (__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L) /* C99 */) )
37 # if defined(_AIX)
38 # include <inttypes.h>
39 # else
40 # include <stdint.h> /* intptr_t */
41 # endif
42 typedef uint8_t BYTE;
43 typedef uint8_t U8;
44 typedef int8_t S8;
45 typedef uint16_t U16;
46 typedef int16_t S16;
47 typedef uint32_t U32;
48 typedef int32_t S32;
49 typedef uint64_t U64;
50 typedef int64_t S64;
51 #else
52 # include <limits.h>
53 #if CHAR_BIT != 8
54 # error "this implementation requires char to be exactly 8-bit type"
55 #endif
56 typedef unsigned char BYTE;
57 typedef unsigned char U8;
58 typedef signed char S8;
59 #if USHRT_MAX != 65535
60 # error "this implementation requires short to be exactly 16-bit type"
61 #endif
62 typedef unsigned short U16;
63 typedef signed short S16;
64 #if UINT_MAX != 4294967295
65 # error "this implementation requires int to be exactly 32-bit type"
66 #endif
67 typedef unsigned int U32;
68 typedef signed int S32;
69 /* note : there are no limits defined for long long type in C90.
70 * limits exist in C99, however, in such case, <stdint.h> is preferred */
71 typedef unsigned long long U64;
72 typedef signed long long S64;
73 #endif
74
75 /*-**************************************************************
76 * Memory I/O API
77 *****************************************************************/
78 /*=== Static platform detection ===*/
79 MEM_STATIC unsigned MEM_32bits(void);
80 MEM_STATIC unsigned MEM_64bits(void);
81 MEM_STATIC unsigned MEM_isLittleEndian(void);
82
83 /*=== Native unaligned read/write ===*/
84 MEM_STATIC U16 MEM_read16(const void* memPtr);
85 MEM_STATIC U32 MEM_read32(const void* memPtr);
86 MEM_STATIC U64 MEM_read64(const void* memPtr);
87 MEM_STATIC size_t MEM_readST(const void* memPtr);
88
89 MEM_STATIC void MEM_write16(void* memPtr, U16 value);
90 MEM_STATIC void MEM_write32(void* memPtr, U32 value);
91 MEM_STATIC void MEM_write64(void* memPtr, U64 value);
92
93 /*=== Little endian unaligned read/write ===*/
94 MEM_STATIC U16 MEM_readLE16(const void* memPtr);
95 MEM_STATIC U32 MEM_readLE24(const void* memPtr);
96 MEM_STATIC U32 MEM_readLE32(const void* memPtr);
97 MEM_STATIC U64 MEM_readLE64(const void* memPtr);
98 MEM_STATIC size_t MEM_readLEST(const void* memPtr);
99
100 MEM_STATIC void MEM_writeLE16(void* memPtr, U16 val);
101 MEM_STATIC void MEM_writeLE24(void* memPtr, U32 val);
102 MEM_STATIC void MEM_writeLE32(void* memPtr, U32 val32);
103 MEM_STATIC void MEM_writeLE64(void* memPtr, U64 val64);
104 MEM_STATIC void MEM_writeLEST(void* memPtr, size_t val);
105
106 /*=== Big endian unaligned read/write ===*/
107 MEM_STATIC U32 MEM_readBE32(const void* memPtr);
108 MEM_STATIC U64 MEM_readBE64(const void* memPtr);
109 MEM_STATIC size_t MEM_readBEST(const void* memPtr);
110
111 MEM_STATIC void MEM_writeBE32(void* memPtr, U32 val32);
112 MEM_STATIC void MEM_writeBE64(void* memPtr, U64 val64);
113 MEM_STATIC void MEM_writeBEST(void* memPtr, size_t val);
114
115 /*=== Byteswap ===*/
116 MEM_STATIC U32 MEM_swap32(U32 in);
117 MEM_STATIC U64 MEM_swap64(U64 in);
118 MEM_STATIC size_t MEM_swapST(size_t in);
119
120
121 /*-**************************************************************
122 * Memory I/O Implementation
123 *****************************************************************/
124 /* MEM_FORCE_MEMORY_ACCESS : For accessing unaligned memory:
125 * Method 0 : always use `memcpy()`. Safe and portable.
126 * Method 1 : Use compiler extension to set unaligned access.
127 * Method 2 : direct access. This method is portable but violate C standard.
128 * It can generate buggy code on targets depending on alignment.
129 * Default : method 1 if supported, else method 0
130 */
131 #ifndef MEM_FORCE_MEMORY_ACCESS /* can be defined externally, on command line for example */
132 # ifdef __GNUC__
133 # define MEM_FORCE_MEMORY_ACCESS 1
134 # endif
135 #endif
136
MEM_32bits(void)137 MEM_STATIC unsigned MEM_32bits(void) { return sizeof(size_t)==4; }
MEM_64bits(void)138 MEM_STATIC unsigned MEM_64bits(void) { return sizeof(size_t)==8; }
139
MEM_isLittleEndian(void)140 MEM_STATIC unsigned MEM_isLittleEndian(void)
141 {
142 #if defined(__BYTE_ORDER__) && defined(__ORDER_LITTLE_ENDIAN__) && (__BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__)
143 return 1;
144 #elif defined(__BYTE_ORDER__) && defined(__ORDER_BIG_ENDIAN__) && (__BYTE_ORDER__ == __ORDER_BIG_ENDIAN__)
145 return 0;
146 #elif defined(__clang__) && __LITTLE_ENDIAN__
147 return 1;
148 #elif defined(__clang__) && __BIG_ENDIAN__
149 return 0;
150 #elif defined(_MSC_VER) && (_M_X64 || _M_IX86)
151 return 1;
152 #elif defined(__DMC__) && defined(_M_IX86)
153 return 1;
154 #elif defined(__IAR_SYSTEMS_ICC__) && __LITTLE_ENDIAN__
155 return 1;
156 #else
157 const union { U32 u; BYTE c[4]; } one = { 1 }; /* don't use static : performance detrimental */
158 return one.c[0];
159 #endif
160 }
161
162 #if defined(MEM_FORCE_MEMORY_ACCESS) && (MEM_FORCE_MEMORY_ACCESS==2)
163
164 /* violates C standard, by lying on structure alignment.
165 Only use if no other choice to achieve best performance on target platform */
MEM_read16(const void * memPtr)166 MEM_STATIC U16 MEM_read16(const void* memPtr) { return *(const U16*) memPtr; }
MEM_read32(const void * memPtr)167 MEM_STATIC U32 MEM_read32(const void* memPtr) { return *(const U32*) memPtr; }
MEM_read64(const void * memPtr)168 MEM_STATIC U64 MEM_read64(const void* memPtr) { return *(const U64*) memPtr; }
MEM_readST(const void * memPtr)169 MEM_STATIC size_t MEM_readST(const void* memPtr) { return *(const size_t*) memPtr; }
170
MEM_write16(void * memPtr,U16 value)171 MEM_STATIC void MEM_write16(void* memPtr, U16 value) { *(U16*)memPtr = value; }
MEM_write32(void * memPtr,U32 value)172 MEM_STATIC void MEM_write32(void* memPtr, U32 value) { *(U32*)memPtr = value; }
MEM_write64(void * memPtr,U64 value)173 MEM_STATIC void MEM_write64(void* memPtr, U64 value) { *(U64*)memPtr = value; }
174
175 #elif defined(MEM_FORCE_MEMORY_ACCESS) && (MEM_FORCE_MEMORY_ACCESS==1)
176
177 typedef __attribute__((aligned(1))) U16 unalign16;
178 typedef __attribute__((aligned(1))) U32 unalign32;
179 typedef __attribute__((aligned(1))) U64 unalign64;
180 typedef __attribute__((aligned(1))) size_t unalignArch;
181
MEM_read16(const void * ptr)182 MEM_STATIC U16 MEM_read16(const void* ptr) { return *(const unalign16*)ptr; }
MEM_read32(const void * ptr)183 MEM_STATIC U32 MEM_read32(const void* ptr) { return *(const unalign32*)ptr; }
MEM_read64(const void * ptr)184 MEM_STATIC U64 MEM_read64(const void* ptr) { return *(const unalign64*)ptr; }
MEM_readST(const void * ptr)185 MEM_STATIC size_t MEM_readST(const void* ptr) { return *(const unalignArch*)ptr; }
186
MEM_write16(void * memPtr,U16 value)187 MEM_STATIC void MEM_write16(void* memPtr, U16 value) { *(unalign16*)memPtr = value; }
MEM_write32(void * memPtr,U32 value)188 MEM_STATIC void MEM_write32(void* memPtr, U32 value) { *(unalign32*)memPtr = value; }
MEM_write64(void * memPtr,U64 value)189 MEM_STATIC void MEM_write64(void* memPtr, U64 value) { *(unalign64*)memPtr = value; }
190
191 #else
192
193 /* default method, safe and standard.
194 can sometimes prove slower */
195
MEM_read16(const void * memPtr)196 MEM_STATIC U16 MEM_read16(const void* memPtr)
197 {
198 U16 val; ZSTD_memcpy(&val, memPtr, sizeof(val)); return val;
199 }
200
MEM_read32(const void * memPtr)201 MEM_STATIC U32 MEM_read32(const void* memPtr)
202 {
203 U32 val; ZSTD_memcpy(&val, memPtr, sizeof(val)); return val;
204 }
205
MEM_read64(const void * memPtr)206 MEM_STATIC U64 MEM_read64(const void* memPtr)
207 {
208 U64 val; ZSTD_memcpy(&val, memPtr, sizeof(val)); return val;
209 }
210
MEM_readST(const void * memPtr)211 MEM_STATIC size_t MEM_readST(const void* memPtr)
212 {
213 size_t val; ZSTD_memcpy(&val, memPtr, sizeof(val)); return val;
214 }
215
MEM_write16(void * memPtr,U16 value)216 MEM_STATIC void MEM_write16(void* memPtr, U16 value)
217 {
218 ZSTD_memcpy(memPtr, &value, sizeof(value));
219 }
220
MEM_write32(void * memPtr,U32 value)221 MEM_STATIC void MEM_write32(void* memPtr, U32 value)
222 {
223 ZSTD_memcpy(memPtr, &value, sizeof(value));
224 }
225
MEM_write64(void * memPtr,U64 value)226 MEM_STATIC void MEM_write64(void* memPtr, U64 value)
227 {
228 ZSTD_memcpy(memPtr, &value, sizeof(value));
229 }
230
231 #endif /* MEM_FORCE_MEMORY_ACCESS */
232
MEM_swap32_fallback(U32 in)233 MEM_STATIC U32 MEM_swap32_fallback(U32 in)
234 {
235 return ((in << 24) & 0xff000000 ) |
236 ((in << 8) & 0x00ff0000 ) |
237 ((in >> 8) & 0x0000ff00 ) |
238 ((in >> 24) & 0x000000ff );
239 }
240
MEM_swap32(U32 in)241 MEM_STATIC U32 MEM_swap32(U32 in)
242 {
243 #if defined(_MSC_VER) /* Visual Studio */
244 return _byteswap_ulong(in);
245 #elif (defined (__GNUC__) && (__GNUC__ * 100 + __GNUC_MINOR__ >= 403)) \
246 || (defined(__clang__) && __has_builtin(__builtin_bswap32))
247 return __builtin_bswap32(in);
248 #elif defined(__ICCARM__)
249 return __REV(in);
250 #else
251 return MEM_swap32_fallback(in);
252 #endif
253 }
254
MEM_swap64_fallback(U64 in)255 MEM_STATIC U64 MEM_swap64_fallback(U64 in)
256 {
257 return ((in << 56) & 0xff00000000000000ULL) |
258 ((in << 40) & 0x00ff000000000000ULL) |
259 ((in << 24) & 0x0000ff0000000000ULL) |
260 ((in << 8) & 0x000000ff00000000ULL) |
261 ((in >> 8) & 0x00000000ff000000ULL) |
262 ((in >> 24) & 0x0000000000ff0000ULL) |
263 ((in >> 40) & 0x000000000000ff00ULL) |
264 ((in >> 56) & 0x00000000000000ffULL);
265 }
266
MEM_swap64(U64 in)267 MEM_STATIC U64 MEM_swap64(U64 in)
268 {
269 #if defined(_MSC_VER) /* Visual Studio */
270 return _byteswap_uint64(in);
271 #elif (defined (__GNUC__) && (__GNUC__ * 100 + __GNUC_MINOR__ >= 403)) \
272 || (defined(__clang__) && __has_builtin(__builtin_bswap64))
273 return __builtin_bswap64(in);
274 #else
275 return MEM_swap64_fallback(in);
276 #endif
277 }
278
MEM_swapST(size_t in)279 MEM_STATIC size_t MEM_swapST(size_t in)
280 {
281 if (MEM_32bits())
282 return (size_t)MEM_swap32((U32)in);
283 else
284 return (size_t)MEM_swap64((U64)in);
285 }
286
287 /*=== Little endian r/w ===*/
288
MEM_readLE16(const void * memPtr)289 MEM_STATIC U16 MEM_readLE16(const void* memPtr)
290 {
291 if (MEM_isLittleEndian())
292 return MEM_read16(memPtr);
293 else {
294 const BYTE* p = (const BYTE*)memPtr;
295 return (U16)(p[0] + (p[1]<<8));
296 }
297 }
298
MEM_writeLE16(void * memPtr,U16 val)299 MEM_STATIC void MEM_writeLE16(void* memPtr, U16 val)
300 {
301 if (MEM_isLittleEndian()) {
302 MEM_write16(memPtr, val);
303 } else {
304 BYTE* p = (BYTE*)memPtr;
305 p[0] = (BYTE)val;
306 p[1] = (BYTE)(val>>8);
307 }
308 }
309
MEM_readLE24(const void * memPtr)310 MEM_STATIC U32 MEM_readLE24(const void* memPtr)
311 {
312 return (U32)MEM_readLE16(memPtr) + ((U32)(((const BYTE*)memPtr)[2]) << 16);
313 }
314
MEM_writeLE24(void * memPtr,U32 val)315 MEM_STATIC void MEM_writeLE24(void* memPtr, U32 val)
316 {
317 MEM_writeLE16(memPtr, (U16)val);
318 ((BYTE*)memPtr)[2] = (BYTE)(val>>16);
319 }
320
MEM_readLE32(const void * memPtr)321 MEM_STATIC U32 MEM_readLE32(const void* memPtr)
322 {
323 if (MEM_isLittleEndian())
324 return MEM_read32(memPtr);
325 else
326 return MEM_swap32(MEM_read32(memPtr));
327 }
328
MEM_writeLE32(void * memPtr,U32 val32)329 MEM_STATIC void MEM_writeLE32(void* memPtr, U32 val32)
330 {
331 if (MEM_isLittleEndian())
332 MEM_write32(memPtr, val32);
333 else
334 MEM_write32(memPtr, MEM_swap32(val32));
335 }
336
MEM_readLE64(const void * memPtr)337 MEM_STATIC U64 MEM_readLE64(const void* memPtr)
338 {
339 if (MEM_isLittleEndian())
340 return MEM_read64(memPtr);
341 else
342 return MEM_swap64(MEM_read64(memPtr));
343 }
344
MEM_writeLE64(void * memPtr,U64 val64)345 MEM_STATIC void MEM_writeLE64(void* memPtr, U64 val64)
346 {
347 if (MEM_isLittleEndian())
348 MEM_write64(memPtr, val64);
349 else
350 MEM_write64(memPtr, MEM_swap64(val64));
351 }
352
MEM_readLEST(const void * memPtr)353 MEM_STATIC size_t MEM_readLEST(const void* memPtr)
354 {
355 if (MEM_32bits())
356 return (size_t)MEM_readLE32(memPtr);
357 else
358 return (size_t)MEM_readLE64(memPtr);
359 }
360
MEM_writeLEST(void * memPtr,size_t val)361 MEM_STATIC void MEM_writeLEST(void* memPtr, size_t val)
362 {
363 if (MEM_32bits())
364 MEM_writeLE32(memPtr, (U32)val);
365 else
366 MEM_writeLE64(memPtr, (U64)val);
367 }
368
369 /*=== Big endian r/w ===*/
370
MEM_readBE32(const void * memPtr)371 MEM_STATIC U32 MEM_readBE32(const void* memPtr)
372 {
373 if (MEM_isLittleEndian())
374 return MEM_swap32(MEM_read32(memPtr));
375 else
376 return MEM_read32(memPtr);
377 }
378
MEM_writeBE32(void * memPtr,U32 val32)379 MEM_STATIC void MEM_writeBE32(void* memPtr, U32 val32)
380 {
381 if (MEM_isLittleEndian())
382 MEM_write32(memPtr, MEM_swap32(val32));
383 else
384 MEM_write32(memPtr, val32);
385 }
386
MEM_readBE64(const void * memPtr)387 MEM_STATIC U64 MEM_readBE64(const void* memPtr)
388 {
389 if (MEM_isLittleEndian())
390 return MEM_swap64(MEM_read64(memPtr));
391 else
392 return MEM_read64(memPtr);
393 }
394
MEM_writeBE64(void * memPtr,U64 val64)395 MEM_STATIC void MEM_writeBE64(void* memPtr, U64 val64)
396 {
397 if (MEM_isLittleEndian())
398 MEM_write64(memPtr, MEM_swap64(val64));
399 else
400 MEM_write64(memPtr, val64);
401 }
402
MEM_readBEST(const void * memPtr)403 MEM_STATIC size_t MEM_readBEST(const void* memPtr)
404 {
405 if (MEM_32bits())
406 return (size_t)MEM_readBE32(memPtr);
407 else
408 return (size_t)MEM_readBE64(memPtr);
409 }
410
MEM_writeBEST(void * memPtr,size_t val)411 MEM_STATIC void MEM_writeBEST(void* memPtr, size_t val)
412 {
413 if (MEM_32bits())
414 MEM_writeBE32(memPtr, (U32)val);
415 else
416 MEM_writeBE64(memPtr, (U64)val);
417 }
418
419 /* code only tested on 32 and 64 bits systems */
MEM_check(void)420 MEM_STATIC void MEM_check(void) { DEBUG_STATIC_ASSERT((sizeof(size_t)==4) || (sizeof(size_t)==8)); }
421
422 #endif /* MEM_H_MODULE */
423