1 // SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0-only
2 /*
3 * Copyright (c) 2016-2020, Yann Collet, Facebook, Inc.
4 * All rights reserved.
5 *
6 * This source code is licensed under both the BSD-style license (found in the
7 * LICENSE file in the root directory of this source tree) and the GPLv2 (found
8 * in the COPYING file in the root directory of this source tree).
9 * You may select, at your option, one of the above-listed licenses.
10 */
11
12 #ifndef MEM_H_MODULE
13 #define MEM_H_MODULE
14
15 #if defined (__cplusplus)
16 extern "C" {
17 #endif
18
19 /*-****************************************
20 * Dependencies
21 ******************************************/
22 #include <stddef.h> /* size_t, ptrdiff_t */
23 #include <string.h> /* memcpy */
24
25
26 /*-****************************************
27 * Compiler specifics
28 ******************************************/
29 #if defined(_MSC_VER) /* Visual Studio */
30 # include <stdlib.h> /* _byteswap_ulong */
31 # include <intrin.h> /* _byteswap_* */
32 #endif
33 #if defined(__GNUC__)
34 # define MEM_STATIC static __inline __attribute__((unused))
35 #elif defined (__cplusplus) || (defined (__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L) /* C99 */)
36 # define MEM_STATIC static inline
37 #elif defined(_MSC_VER)
38 # define MEM_STATIC static __inline
39 #else
40 # define MEM_STATIC static /* this version may generate warnings for unused static functions; disable the relevant warning */
41 #endif
42
43 #ifndef __has_builtin
44 # define __has_builtin(x) 0 /* compat. with non-clang compilers */
45 #endif
46
47 /* code only tested on 32 and 64 bits systems */
48 #define MEM_STATIC_ASSERT(c) { enum { MEM_static_assert = 1/(int)(!!(c)) }; }
MEM_check(void)49 MEM_STATIC void MEM_check(void) { MEM_STATIC_ASSERT((sizeof(size_t)==4) || (sizeof(size_t)==8)); }
50
51 /* detects whether we are being compiled under msan */
52 #if defined (__has_feature)
53 # if __has_feature(memory_sanitizer)
54 # define MEMORY_SANITIZER 1
55 # endif
56 #endif
57
58 #if defined (MEMORY_SANITIZER)
59 /* Not all platforms that support msan provide sanitizers/msan_interface.h.
60 * We therefore declare the functions we need ourselves, rather than trying to
61 * include the header file... */
62
63 #include <stdint.h> /* intptr_t */
64
65 /* Make memory region fully initialized (without changing its contents). */
66 void __msan_unpoison(const volatile void *a, size_t size);
67
68 /* Make memory region fully uninitialized (without changing its contents).
69 This is a legacy interface that does not update origin information. Use
70 __msan_allocated_memory() instead. */
71 void __msan_poison(const volatile void *a, size_t size);
72
73 /* Returns the offset of the first (at least partially) poisoned byte in the
74 memory range, or -1 if the whole range is good. */
75 intptr_t __msan_test_shadow(const volatile void *x, size_t size);
76 #endif
77
78 /* detects whether we are being compiled under asan */
79 #if defined (ZFS_ASAN_ENABLED)
80 # define ADDRESS_SANITIZER 1
81 # define ZSTD_ASAN_DONT_POISON_WORKSPACE
82 #endif
83
84 #if defined (ADDRESS_SANITIZER)
85 /* Not all platforms that support asan provide sanitizers/asan_interface.h.
86 * We therefore declare the functions we need ourselves, rather than trying to
87 * include the header file... */
88
89 /**
90 * Marks a memory region (<c>[addr, addr+size)</c>) as unaddressable.
91 *
92 * This memory must be previously allocated by your program. Instrumented
93 * code is forbidden from accessing addresses in this region until it is
94 * unpoisoned. This function is not guaranteed to poison the entire region -
95 * it could poison only a subregion of <c>[addr, addr+size)</c> due to ASan
96 * alignment restrictions.
97 *
98 * \note This function is not thread-safe because no two threads can poison or
99 * unpoison memory in the same memory region simultaneously.
100 *
101 * \param addr Start of memory region.
102 * \param size Size of memory region. */
103 void __asan_poison_memory_region(void const volatile *addr, size_t size);
104
105 /**
106 * Marks a memory region (<c>[addr, addr+size)</c>) as addressable.
107 *
108 * This memory must be previously allocated by your program. Accessing
109 * addresses in this region is allowed until this region is poisoned again.
110 * This function could unpoison a super-region of <c>[addr, addr+size)</c> due
111 * to ASan alignment restrictions.
112 *
113 * \note This function is not thread-safe because no two threads can
114 * poison or unpoison memory in the same memory region simultaneously.
115 *
116 * \param addr Start of memory region.
117 * \param size Size of memory region. */
118 void __asan_unpoison_memory_region(void const volatile *addr, size_t size);
119 #endif
120
121
122 /*-**************************************************************
123 * Basic Types
124 *****************************************************************/
125 #if !defined (__VMS) && (defined (__cplusplus) || (defined (__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L) /* C99 */) )
126 # include <stdint.h>
127 typedef uint8_t BYTE;
128 typedef uint16_t U16;
129 typedef int16_t S16;
130 typedef uint32_t U32;
131 typedef int32_t S32;
132 typedef uint64_t U64;
133 typedef int64_t S64;
134 #else
135 # include <limits.h>
136 #if CHAR_BIT != 8
137 # error "this implementation requires char to be exactly 8-bit type"
138 #endif
139 typedef unsigned char BYTE;
140 #if USHRT_MAX != 65535
141 # error "this implementation requires short to be exactly 16-bit type"
142 #endif
143 typedef unsigned short U16;
144 typedef signed short S16;
145 #if UINT_MAX != 4294967295
146 # error "this implementation requires int to be exactly 32-bit type"
147 #endif
148 typedef unsigned int U32;
149 typedef signed int S32;
150 /* note : there are no limits defined for long long type in C90.
151 * limits exist in C99, however, in such case, <stdint.h> is preferred */
152 typedef unsigned long long U64;
153 typedef signed long long S64;
154 #endif
155
156
157 /*-**************************************************************
158 * Memory I/O
159 *****************************************************************/
160 /* MEM_FORCE_MEMORY_ACCESS :
161 * By default, access to unaligned memory is controlled by `memcpy()`, which is safe and portable.
162 * Unfortunately, on some target/compiler combinations, the generated assembly is sub-optimal.
163 * The below switch allow to select different access method for improved performance.
164 * Method 0 (default) : use `memcpy()`. Safe and portable.
165 * Method 1 : `__packed` statement. It depends on compiler extension (i.e., not portable).
166 * This method is safe if your compiler supports it, and *generally* as fast or faster than `memcpy`.
167 * Method 2 : direct access. This method is portable but violate C standard.
168 * It can generate buggy code on targets depending on alignment.
169 * In some circumstances, it's the only known way to get the most performance (i.e. GCC + ARMv6)
170 * See http://fastcompression.blogspot.fr/2015/08/accessing-unaligned-memory.html for details.
171 * Prefer these methods in priority order (0 > 1 > 2)
172 */
173 #ifndef MEM_FORCE_MEMORY_ACCESS /* can be defined externally, on command line for example */
174 # 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__) )
175 # define MEM_FORCE_MEMORY_ACCESS 2
176 # elif defined(__INTEL_COMPILER) || defined(__GNUC__) || defined(__ICCARM__)
177 # define MEM_FORCE_MEMORY_ACCESS 1
178 # endif
179 #endif
180
MEM_32bits(void)181 MEM_STATIC unsigned MEM_32bits(void) { return sizeof(size_t)==4; }
MEM_64bits(void)182 MEM_STATIC unsigned MEM_64bits(void) { return sizeof(size_t)==8; }
183
MEM_isLittleEndian(void)184 MEM_STATIC unsigned MEM_isLittleEndian(void)
185 {
186 const union { U32 u; BYTE c[4]; } one = { 1 }; /* don't use static : performance detrimental */
187 return one.c[0];
188 }
189
190 #if defined(MEM_FORCE_MEMORY_ACCESS) && (MEM_FORCE_MEMORY_ACCESS==2)
191
192 /* violates C standard, by lying on structure alignment.
193 Only use if no other choice to achieve best performance on target platform */
MEM_read16(const void * memPtr)194 MEM_STATIC U16 MEM_read16(const void* memPtr) { return *(const U16*) memPtr; }
MEM_read32(const void * memPtr)195 MEM_STATIC U32 MEM_read32(const void* memPtr) { return *(const U32*) memPtr; }
MEM_read64(const void * memPtr)196 MEM_STATIC U64 MEM_read64(const void* memPtr) { return *(const U64*) memPtr; }
MEM_readST(const void * memPtr)197 MEM_STATIC size_t MEM_readST(const void* memPtr) { return *(const size_t*) memPtr; }
198
MEM_write16(void * memPtr,U16 value)199 MEM_STATIC void MEM_write16(void* memPtr, U16 value) { *(U16*)memPtr = value; }
MEM_write32(void * memPtr,U32 value)200 MEM_STATIC void MEM_write32(void* memPtr, U32 value) { *(U32*)memPtr = value; }
MEM_write64(void * memPtr,U64 value)201 MEM_STATIC void MEM_write64(void* memPtr, U64 value) { *(U64*)memPtr = value; }
202
203 #elif defined(MEM_FORCE_MEMORY_ACCESS) && (MEM_FORCE_MEMORY_ACCESS==1)
204
205 /* __pack instructions are safer, but compiler specific, hence potentially problematic for some compilers */
206 /* currently only defined for gcc and icc */
207 #if defined(_MSC_VER) || (defined(__INTEL_COMPILER) && defined(WIN32))
208 __pragma( pack(push, 1) )
209 typedef struct { U16 v; } unalign16;
210 typedef struct { U32 v; } unalign32;
211 typedef struct { U64 v; } unalign64;
212 typedef struct { size_t v; } unalignArch;
__pragma(pack (pop))213 __pragma( pack(pop) )
214 #else
215 typedef struct { U16 v; } __attribute__((packed)) unalign16;
216 typedef struct { U32 v; } __attribute__((packed)) unalign32;
217 typedef struct { U64 v; } __attribute__((packed)) unalign64;
218 typedef struct { size_t v; } __attribute__((packed)) unalignArch;
219 #endif
220
221 MEM_STATIC U16 MEM_read16(const void* ptr) { return ((const unalign16*)ptr)->v; }
MEM_read32(const void * ptr)222 MEM_STATIC U32 MEM_read32(const void* ptr) { return ((const unalign32*)ptr)->v; }
MEM_read64(const void * ptr)223 MEM_STATIC U64 MEM_read64(const void* ptr) { return ((const unalign64*)ptr)->v; }
MEM_readST(const void * ptr)224 MEM_STATIC size_t MEM_readST(const void* ptr) { return ((const unalignArch*)ptr)->v; }
225
MEM_write16(void * memPtr,U16 value)226 MEM_STATIC void MEM_write16(void* memPtr, U16 value) { ((unalign16*)memPtr)->v = value; }
MEM_write32(void * memPtr,U32 value)227 MEM_STATIC void MEM_write32(void* memPtr, U32 value) { ((unalign32*)memPtr)->v = value; }
MEM_write64(void * memPtr,U64 value)228 MEM_STATIC void MEM_write64(void* memPtr, U64 value) { ((unalign64*)memPtr)->v = value; }
229
230 #else
231
232 /* default method, safe and standard.
233 can sometimes prove slower */
234
MEM_read16(const void * memPtr)235 MEM_STATIC U16 MEM_read16(const void* memPtr)
236 {
237 U16 val; memcpy(&val, memPtr, sizeof(val)); return val;
238 }
239
MEM_read32(const void * memPtr)240 MEM_STATIC U32 MEM_read32(const void* memPtr)
241 {
242 U32 val; memcpy(&val, memPtr, sizeof(val)); return val;
243 }
244
MEM_read64(const void * memPtr)245 MEM_STATIC U64 MEM_read64(const void* memPtr)
246 {
247 U64 val; memcpy(&val, memPtr, sizeof(val)); return val;
248 }
249
MEM_readST(const void * memPtr)250 MEM_STATIC size_t MEM_readST(const void* memPtr)
251 {
252 size_t val; memcpy(&val, memPtr, sizeof(val)); return val;
253 }
254
MEM_write16(void * memPtr,U16 value)255 MEM_STATIC void MEM_write16(void* memPtr, U16 value)
256 {
257 memcpy(memPtr, &value, sizeof(value));
258 }
259
MEM_write32(void * memPtr,U32 value)260 MEM_STATIC void MEM_write32(void* memPtr, U32 value)
261 {
262 memcpy(memPtr, &value, sizeof(value));
263 }
264
MEM_write64(void * memPtr,U64 value)265 MEM_STATIC void MEM_write64(void* memPtr, U64 value)
266 {
267 memcpy(memPtr, &value, sizeof(value));
268 }
269
270 #endif /* MEM_FORCE_MEMORY_ACCESS */
271
MEM_swap32(U32 in)272 MEM_STATIC U32 MEM_swap32(U32 in)
273 {
274 #if defined(_MSC_VER) /* Visual Studio */
275 return _byteswap_ulong(in);
276 #elif (defined (__GNUC__) && (__GNUC__ * 100 + __GNUC_MINOR__ >= 403)) \
277 || (defined(__clang__) && __has_builtin(__builtin_bswap32))
278 return __builtin_bswap32(in);
279 #else
280 return ((in << 24) & 0xff000000 ) |
281 ((in << 8) & 0x00ff0000 ) |
282 ((in >> 8) & 0x0000ff00 ) |
283 ((in >> 24) & 0x000000ff );
284 #endif
285 }
286
MEM_swap64(U64 in)287 MEM_STATIC U64 MEM_swap64(U64 in)
288 {
289 #if defined(_MSC_VER) /* Visual Studio */
290 return _byteswap_uint64(in);
291 #elif (defined (__GNUC__) && (__GNUC__ * 100 + __GNUC_MINOR__ >= 403)) \
292 || (defined(__clang__) && __has_builtin(__builtin_bswap64))
293 return __builtin_bswap64(in);
294 #else
295 return ((in << 56) & 0xff00000000000000ULL) |
296 ((in << 40) & 0x00ff000000000000ULL) |
297 ((in << 24) & 0x0000ff0000000000ULL) |
298 ((in << 8) & 0x000000ff00000000ULL) |
299 ((in >> 8) & 0x00000000ff000000ULL) |
300 ((in >> 24) & 0x0000000000ff0000ULL) |
301 ((in >> 40) & 0x000000000000ff00ULL) |
302 ((in >> 56) & 0x00000000000000ffULL);
303 #endif
304 }
305
MEM_swapST(size_t in)306 MEM_STATIC size_t MEM_swapST(size_t in)
307 {
308 if (MEM_32bits())
309 return (size_t)MEM_swap32((U32)in);
310 else
311 return (size_t)MEM_swap64((U64)in);
312 }
313
314 /*=== Little endian r/w ===*/
315
MEM_readLE16(const void * memPtr)316 MEM_STATIC U16 MEM_readLE16(const void* memPtr)
317 {
318 if (MEM_isLittleEndian())
319 return MEM_read16(memPtr);
320 else {
321 const BYTE* p = (const BYTE*)memPtr;
322 return (U16)(p[0] + (p[1]<<8));
323 }
324 }
325
MEM_writeLE16(void * memPtr,U16 val)326 MEM_STATIC void MEM_writeLE16(void* memPtr, U16 val)
327 {
328 if (MEM_isLittleEndian()) {
329 MEM_write16(memPtr, val);
330 } else {
331 BYTE* p = (BYTE*)memPtr;
332 p[0] = (BYTE)val;
333 p[1] = (BYTE)(val>>8);
334 }
335 }
336
MEM_readLE24(const void * memPtr)337 MEM_STATIC U32 MEM_readLE24(const void* memPtr)
338 {
339 return MEM_readLE16(memPtr) + (((const BYTE*)memPtr)[2] << 16);
340 }
341
MEM_writeLE24(void * memPtr,U32 val)342 MEM_STATIC void MEM_writeLE24(void* memPtr, U32 val)
343 {
344 MEM_writeLE16(memPtr, (U16)val);
345 ((BYTE*)memPtr)[2] = (BYTE)(val>>16);
346 }
347
MEM_readLE32(const void * memPtr)348 MEM_STATIC U32 MEM_readLE32(const void* memPtr)
349 {
350 if (MEM_isLittleEndian())
351 return MEM_read32(memPtr);
352 else
353 return MEM_swap32(MEM_read32(memPtr));
354 }
355
MEM_writeLE32(void * memPtr,U32 val32)356 MEM_STATIC void MEM_writeLE32(void* memPtr, U32 val32)
357 {
358 if (MEM_isLittleEndian())
359 MEM_write32(memPtr, val32);
360 else
361 MEM_write32(memPtr, MEM_swap32(val32));
362 }
363
MEM_readLE64(const void * memPtr)364 MEM_STATIC U64 MEM_readLE64(const void* memPtr)
365 {
366 if (MEM_isLittleEndian())
367 return MEM_read64(memPtr);
368 else
369 return MEM_swap64(MEM_read64(memPtr));
370 }
371
MEM_writeLE64(void * memPtr,U64 val64)372 MEM_STATIC void MEM_writeLE64(void* memPtr, U64 val64)
373 {
374 if (MEM_isLittleEndian())
375 MEM_write64(memPtr, val64);
376 else
377 MEM_write64(memPtr, MEM_swap64(val64));
378 }
379
MEM_readLEST(const void * memPtr)380 MEM_STATIC size_t MEM_readLEST(const void* memPtr)
381 {
382 if (MEM_32bits())
383 return (size_t)MEM_readLE32(memPtr);
384 else
385 return (size_t)MEM_readLE64(memPtr);
386 }
387
MEM_writeLEST(void * memPtr,size_t val)388 MEM_STATIC void MEM_writeLEST(void* memPtr, size_t val)
389 {
390 if (MEM_32bits())
391 MEM_writeLE32(memPtr, (U32)val);
392 else
393 MEM_writeLE64(memPtr, (U64)val);
394 }
395
396 /*=== Big endian r/w ===*/
397
MEM_readBE32(const void * memPtr)398 MEM_STATIC U32 MEM_readBE32(const void* memPtr)
399 {
400 if (MEM_isLittleEndian())
401 return MEM_swap32(MEM_read32(memPtr));
402 else
403 return MEM_read32(memPtr);
404 }
405
MEM_writeBE32(void * memPtr,U32 val32)406 MEM_STATIC void MEM_writeBE32(void* memPtr, U32 val32)
407 {
408 if (MEM_isLittleEndian())
409 MEM_write32(memPtr, MEM_swap32(val32));
410 else
411 MEM_write32(memPtr, val32);
412 }
413
MEM_readBE64(const void * memPtr)414 MEM_STATIC U64 MEM_readBE64(const void* memPtr)
415 {
416 if (MEM_isLittleEndian())
417 return MEM_swap64(MEM_read64(memPtr));
418 else
419 return MEM_read64(memPtr);
420 }
421
MEM_writeBE64(void * memPtr,U64 val64)422 MEM_STATIC void MEM_writeBE64(void* memPtr, U64 val64)
423 {
424 if (MEM_isLittleEndian())
425 MEM_write64(memPtr, MEM_swap64(val64));
426 else
427 MEM_write64(memPtr, val64);
428 }
429
MEM_readBEST(const void * memPtr)430 MEM_STATIC size_t MEM_readBEST(const void* memPtr)
431 {
432 if (MEM_32bits())
433 return (size_t)MEM_readBE32(memPtr);
434 else
435 return (size_t)MEM_readBE64(memPtr);
436 }
437
MEM_writeBEST(void * memPtr,size_t val)438 MEM_STATIC void MEM_writeBEST(void* memPtr, size_t val)
439 {
440 if (MEM_32bits())
441 MEM_writeBE32(memPtr, (U32)val);
442 else
443 MEM_writeBE64(memPtr, (U64)val);
444 }
445
446
447 #if defined (__cplusplus)
448 }
449 #endif
450
451 #endif /* MEM_H_MODULE */
452