/usr/include/crcutil/crc32c_sse4.h is in libcrcutil-dev 1.0-3.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 | // Copyright 2010 Google Inc. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// Implements CRC32C using Intel's SSE4 crc32 instruction.
// Uses _mm_crc32_u64/32/8 intrinsics if CRCUTIL_USE_MM_CRC32 is not zero,
// emilates intrinsics via CRC_WORD/CRC_BYTE otherwise.
#ifndef CRCUTIL_CRC32C_SSE4_H_
#define CRCUTIL_CRC32C_SSE4_H_
#include "gf_util.h" // base types, gf_util class, etc.
#include "crc32c_sse4_intrin.h" // _mm_crc32_u* intrinsics
#if HAVE_I386 || HAVE_AMD64
#if CRCUTIL_USE_MM_CRC32
#if HAVE_I386
#define CRC_UPDATE_WORD(crc, value) (crc = _mm_crc32_u32(crc, (value)))
#else
#define CRC_UPDATE_WORD(crc, value) (crc = _mm_crc32_u64(crc, (value)))
#endif // HAVE_I386
#define CRC_UPDATE_BYTE(crc, value) \
(crc = _mm_crc32_u8(static_cast<uint32>(crc), static_cast<uint8>(value)))
#else
#include "generic_crc.h"
#define CRC_UPDATE_WORD(crc, value) do { \
size_t buf = (value); \
CRC_WORD(this, crc, buf); \
} while (0)
#define CRC_UPDATE_BYTE(crc, value) do { \
CRC_BYTE(this, crc, (value)); \
} while (0)
#endif // CRCUTIL_USE_MM_CRC32
namespace crcutil {
#pragma pack(push, 16)
// Since the same pieces should be parameterized in many different places
// and we do not want to introduce a mistake which is rather hard to find,
// use a macro to enumerate all block sizes.
//
// Block sizes and number of stripes were tuned for best performance.
//
// All constants should be literal constants (too lazy to fix the macro).
//
// The use of different "macro_first", "macro", and "macro_last"
// allows generation of different code for smallest, in between,
// and largest block sizes.
//
// This macro shall be kept in sync with
// CRC32C_SSE4_ENUMERATE_ALL_BLOCKS_DESCENDING.
// Failure to do so will cause compile-time error.
#define CRC32C_SSE4_ENUMERATE_ALL_BLOCKS_ASCENDING( \
macro_smallest, macro, macro_largest) \
macro_smallest(512, 3); \
macro(1024, 3); \
macro(4096, 3); \
macro_largest(32768, 3)
// This macro shall be kept in sync with
// CRC32C_SSE4_ENUMERATE_ALL_BLOCKS_ASCENDING.
// Failure to do so will cause compile-time error.
#define CRC32C_SSE4_ENUMERATE_ALL_BLOCKS_DESCENDING( \
macro_smallest, macro, macro_largest) \
macro_largest(32768, 3); \
macro(4096, 3); \
macro(1024, 3); \
macro_smallest(512, 3)
// Enumerates all block sizes.
#define CRC32C_SSE4_ENUMERATE_ALL_BLOCKS(macro) \
CRC32C_SSE4_ENUMERATE_ALL_BLOCKS_ASCENDING(macro, macro, macro)
#define CRC32C_SSE4_STRIPE_SIZE(block_size, num_stripes) \
(((block_size) / (num_stripes)) & ~(sizeof(size_t) - 1))
#define CRC32C_SSE4_BLOCK_SIZE(block_size, num_stripes) \
(CRC32C_SSE4_STRIPE_SIZE(block_size, num_stripes) * (num_stripes))
#define CRC32C_SSE4_MUL_TABLE(block_size, num_stripes) \
mul_table_##block_size##_##num_blocks##_
class RollingCrc32cSSE4;
class Crc32cSSE4 {
public:
// Exports Crc, TableEntry, and Word (needed by RollingCrc).
typedef size_t Crc;
typedef Crc Word;
typedef Crc TableEntry;
Crc32cSSE4() {}
// Initializes the tables given generating polynomial of degree (degree).
// If "canonical" is true, crc value will be XOR'ed with (-1) before and
// after actual CRC computation.
explicit Crc32cSSE4(bool canonical) {
Init(canonical);
}
void Init(bool canonical);
// Initializes the tables given generating polynomial of degree.
// If "canonical" is true, crc value will be XOR'ed with (-1) before and
// after actual CRC computation.
// Provided for compatibility with GenericCrc.
Crc32cSSE4(const Crc &generating_polynomial,
size_t degree,
bool canonical) {
Init(generating_polynomial, degree, canonical);
}
void Init(const Crc &generating_polynomial,
size_t degree,
bool canonical) {
if (generating_polynomial == FixedGeneratingPolynomial() &&
degree == FixedDegree()) {
Init(canonical);
}
}
// Returns fixed generating polymonial the class implements.
static Crc FixedGeneratingPolynomial() {
return 0x82f63b78;
}
// Returns degree of fixed generating polymonial the class implements.
static Crc FixedDegree() {
return 32;
}
// Returns base class.
const GfUtil<Crc> &Base() const { return base_; }
// Computes CRC32.
size_t CrcDefault(const void *data, size_t bytes, const Crc &crc) const {
return Crc32c(data, bytes, crc);
}
// Returns true iff crc32 instruction is available.
static bool IsSSE42Available();
protected:
// Actual implementation.
size_t Crc32c(const void *data, size_t bytes, Crc crc) const;
enum {
kTableEntryBits = 8,
kTableEntries = 1 << kTableEntryBits,
kNumTables = (32 + kTableEntryBits - 1) / kTableEntryBits,
kNumTablesHalfLo = kNumTables / 2,
kNumTablesHalfHi = (kNumTables + 1) / 2,
kUnrolledLoopCount = 8,
kUnrolledLoopBytes = kUnrolledLoopCount * sizeof(size_t),
};
// May be set to size_t or uint32, whichever is faster.
typedef uint32 Entry;
#define DECLARE_MUL_TABLE(block_size, num_stripes) \
Entry CRC32C_SSE4_MUL_TABLE(block_size, num_stripes) \
[kNumTables][kTableEntries]
CRC32C_SSE4_ENUMERATE_ALL_BLOCKS(DECLARE_MUL_TABLE);
#undef DECLARE_MUL_TABLE
GfUtil<Crc> base_;
#if !CRCUTIL_USE_MM_CRC32
TableEntry crc_word_[sizeof(Word)][256];
friend class RollingCrc32cSSE4;
#endif // !CRCUTIL_USE_MM_CRC32
} GCC_ALIGN_ATTRIBUTE(16);
class RollingCrc32cSSE4 {
public:
typedef Crc32cSSE4::Crc Crc;
typedef Crc32cSSE4::TableEntry TableEntry;
typedef Crc32cSSE4::Word Word;
RollingCrc32cSSE4() {}
// Initializes internal data structures.
// Retains reference to "crc" instance -- it is used by Start().
RollingCrc32cSSE4(const Crc32cSSE4 &crc,
size_t roll_window_bytes,
const Crc &start_value) {
Init(crc, roll_window_bytes, start_value);
}
void Init(const Crc32cSSE4 &crc,
size_t roll_window_bytes,
const Crc &start_value);
// Computes crc of "roll_window_bytes" using
// "start_value" of "crc" (see Init()).
Crc Start(const void *data) const {
return crc_->CrcDefault(data, roll_window_bytes_, start_value_);
}
// Computes CRC of "roll_window_bytes" starting in next position.
Crc Roll(const Crc &old_crc, size_t byte_out, size_t byte_in) const {
Crc crc = old_crc;
CRC_UPDATE_BYTE(crc, byte_in);
crc ^= out_[byte_out];
return crc;
}
// Returns start value.
Crc StartValue() const { return start_value_; }
// Returns length of roll window.
size_t WindowBytes() const { return roll_window_bytes_; }
protected:
typedef Crc Entry;
Entry out_[256];
// Used only by Start().
Crc start_value_;
const Crc32cSSE4 *crc_;
size_t roll_window_bytes_;
#if !CRCUTIL_USE_MM_CRC32
TableEntry crc_word_[sizeof(Word)][256];
#endif // !CRCUTIL_USE_MM_CRC32
} GCC_ALIGN_ATTRIBUTE(16);
#pragma pack(pop)
} // namespace crcutil
#endif // HAVE_I386 || HAVE_AMD64
#endif // CRCUTIL_CRC32C_SSE4_H_
|