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