1 // SPDX-License-Identifier: 0BSD
2
3 ///////////////////////////////////////////////////////////////////////////////
4 //
5 /// \file crc64.c
6 /// \brief CRC64 calculation
7 //
8 // Authors: Lasse Collin
9 // Ilya Kurdyukov
10 //
11 ///////////////////////////////////////////////////////////////////////////////
12
13 #include "check.h"
14 #include "crc_common.h"
15
16 #if defined(CRC_X86_CLMUL)
17 # define BUILDING_CRC64_CLMUL
18 # include "crc_x86_clmul.h"
19 #endif
20
21
22 #ifdef CRC64_GENERIC
23
24 /////////////////////////////////
25 // Generic slice-by-four CRC64 //
26 /////////////////////////////////
27
28 #ifdef WORDS_BIGENDIAN
29 # define A1(x) ((x) >> 56)
30 #else
31 # define A1 A
32 #endif
33
34
35 // See the comments in crc32_fast.c. They aren't duplicated here.
36 static uint64_t
crc64_generic(const uint8_t * buf,size_t size,uint64_t crc)37 crc64_generic(const uint8_t *buf, size_t size, uint64_t crc)
38 {
39 crc = ~crc;
40
41 #ifdef WORDS_BIGENDIAN
42 crc = byteswap64(crc);
43 #endif
44
45 if (size > 4) {
46 while ((uintptr_t)(buf) & 3) {
47 crc = lzma_crc64_table[0][*buf++ ^ A1(crc)] ^ S8(crc);
48 --size;
49 }
50
51 const uint8_t *const limit = buf + (size & ~(size_t)(3));
52 size &= (size_t)(3);
53
54 while (buf < limit) {
55 #ifdef WORDS_BIGENDIAN
56 const uint32_t tmp = (uint32_t)(crc >> 32)
57 ^ aligned_read32ne(buf);
58 #else
59 const uint32_t tmp = (uint32_t)crc
60 ^ aligned_read32ne(buf);
61 #endif
62 buf += 4;
63
64 crc = lzma_crc64_table[3][A(tmp)]
65 ^ lzma_crc64_table[2][B(tmp)]
66 ^ S32(crc)
67 ^ lzma_crc64_table[1][C(tmp)]
68 ^ lzma_crc64_table[0][D(tmp)];
69 }
70 }
71
72 while (size-- != 0)
73 crc = lzma_crc64_table[0][*buf++ ^ A1(crc)] ^ S8(crc);
74
75 #ifdef WORDS_BIGENDIAN
76 crc = byteswap64(crc);
77 #endif
78
79 return ~crc;
80 }
81 #endif
82
83
84 #if defined(CRC64_GENERIC) && defined(CRC64_ARCH_OPTIMIZED)
85
86 //////////////////////////
87 // Function dispatching //
88 //////////////////////////
89
90 // If both the generic and arch-optimized implementations are usable, then
91 // the function that is used is selected at runtime. See crc32_fast.c.
92
93 typedef uint64_t (*crc64_func_type)(
94 const uint8_t *buf, size_t size, uint64_t crc);
95
96 static crc64_func_type
crc64_resolve(void)97 crc64_resolve(void)
98 {
99 return is_arch_extension_supported()
100 ? &crc64_arch_optimized : &crc64_generic;
101 }
102
103 #ifdef HAVE_FUNC_ATTRIBUTE_CONSTRUCTOR
104 # define CRC64_SET_FUNC_ATTR __attribute__((__constructor__))
105 static crc64_func_type crc64_func;
106 #else
107 # define CRC64_SET_FUNC_ATTR
108 static uint64_t crc64_dispatch(const uint8_t *buf, size_t size, uint64_t crc);
109 static crc64_func_type crc64_func = &crc64_dispatch;
110 #endif
111
112
113 CRC64_SET_FUNC_ATTR
114 static void
crc64_set_func(void)115 crc64_set_func(void)
116 {
117 crc64_func = crc64_resolve();
118 return;
119 }
120
121
122 #ifndef HAVE_FUNC_ATTRIBUTE_CONSTRUCTOR
123 static uint64_t
crc64_dispatch(const uint8_t * buf,size_t size,uint64_t crc)124 crc64_dispatch(const uint8_t *buf, size_t size, uint64_t crc)
125 {
126 crc64_set_func();
127 return crc64_func(buf, size, crc);
128 }
129 #endif
130 #endif
131
132
133 extern LZMA_API(uint64_t)
lzma_crc64(const uint8_t * buf,size_t size,uint64_t crc)134 lzma_crc64(const uint8_t *buf, size_t size, uint64_t crc)
135 {
136 #if defined(CRC64_GENERIC) && defined(CRC64_ARCH_OPTIMIZED)
137
138 #ifdef CRC_USE_GENERIC_FOR_SMALL_INPUTS
139 if (size <= 16)
140 return crc64_generic(buf, size, crc);
141 #endif
142 return crc64_func(buf, size, crc);
143
144 #elif defined(CRC64_ARCH_OPTIMIZED)
145 // If arch-optimized version is used unconditionally without runtime
146 // CPU detection then omitting the generic version and its 8 KiB
147 // lookup table makes the library smaller.
148 //
149 // FIXME: Lookup table isn't currently omitted on 32-bit x86,
150 // see crc64_table.c.
151 return crc64_arch_optimized(buf, size, crc);
152
153 #else
154 return crc64_generic(buf, size, crc);
155 #endif
156 }
157