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Side by Side Diff: base/containers/hash_tables.h

Issue 1538743002: Switch to standard integer types in base/. (Closed) Base URL: https://chromium.googlesource.com/chromium/src.git@master
Patch Set: DEPS roll too Created 4 years, 12 months ago
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1 // Copyright (c) 2011 The Chromium Authors. All rights reserved. 1 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be 2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file. 3 // found in the LICENSE file.
4 // 4 //
5 5
6 // 6 //
7 // Deal with the differences between Microsoft and GNU implemenations 7 // Deal with the differences between Microsoft and GNU implemenations
8 // of hash_map. Allows all platforms to use |base::hash_map| and 8 // of hash_map. Allows all platforms to use |base::hash_map| and
9 // |base::hash_set|. 9 // |base::hash_set|.
10 // eg: 10 // eg:
11 // base::hash_map<int> my_map; 11 // base::hash_map<int> my_map;
12 // base::hash_set<int> my_set; 12 // base::hash_set<int> my_set;
13 // 13 //
14 // NOTE: It is an explicit non-goal of this class to provide a generic hash 14 // NOTE: It is an explicit non-goal of this class to provide a generic hash
15 // function for pointers. If you want to hash a pointers to a particular class, 15 // function for pointers. If you want to hash a pointers to a particular class,
16 // please define the template specialization elsewhere (for example, in its 16 // please define the template specialization elsewhere (for example, in its
17 // header file) and keep it specific to just pointers to that class. This is 17 // header file) and keep it specific to just pointers to that class. This is
18 // because identity hashes are not desirable for all types that might show up 18 // because identity hashes are not desirable for all types that might show up
19 // in containers as pointers. 19 // in containers as pointers.
20 20
21 #ifndef BASE_CONTAINERS_HASH_TABLES_H_ 21 #ifndef BASE_CONTAINERS_HASH_TABLES_H_
22 #define BASE_CONTAINERS_HASH_TABLES_H_ 22 #define BASE_CONTAINERS_HASH_TABLES_H_
23 23
24 #include <stddef.h>
25 #include <stdint.h>
26
24 #include <utility> 27 #include <utility>
25 28
26 #include "base/basictypes.h"
27 #include "base/strings/string16.h" 29 #include "base/strings/string16.h"
28 #include "build/build_config.h" 30 #include "build/build_config.h"
29 31
30 #if defined(COMPILER_MSVC) 32 #if defined(COMPILER_MSVC)
31 #include <unordered_map> 33 #include <unordered_map>
32 #include <unordered_set> 34 #include <unordered_set>
33 35
34 #define BASE_HASH_NAMESPACE std 36 #define BASE_HASH_NAMESPACE std
35 37
36 #elif defined(COMPILER_GCC) 38 #elif defined(COMPILER_GCC)
(...skipping 152 matching lines...) Expand 10 before | Expand all | Expand 10 after
189 191
190 // Implement hashing for pairs of at-most 32 bit integer values. 192 // Implement hashing for pairs of at-most 32 bit integer values.
191 // When size_t is 32 bits, we turn the 64-bit hash code into 32 bits by using 193 // When size_t is 32 bits, we turn the 64-bit hash code into 32 bits by using
192 // multiply-add hashing. This algorithm, as described in 194 // multiply-add hashing. This algorithm, as described in
193 // Theorem 4.3.3 of the thesis "Über die Komplexität der Multiplikation in 195 // Theorem 4.3.3 of the thesis "Über die Komplexität der Multiplikation in
194 // eingeschränkten Branchingprogrammmodellen" by Woelfel, is: 196 // eingeschränkten Branchingprogrammmodellen" by Woelfel, is:
195 // 197 //
196 // h32(x32, y32) = (h64(x32, y32) * rand_odd64 + rand16 * 2^16) % 2^64 / 2^32 198 // h32(x32, y32) = (h64(x32, y32) * rand_odd64 + rand16 * 2^16) % 2^64 / 2^32
197 // 199 //
198 // Contact danakj@chromium.org for any questions. 200 // Contact danakj@chromium.org for any questions.
199 inline std::size_t HashInts32(uint32 value1, uint32 value2) { 201 inline std::size_t HashInts32(uint32_t value1, uint32_t value2) {
200 uint64 value1_64 = value1; 202 uint64_t value1_64 = value1;
201 uint64 hash64 = (value1_64 << 32) | value2; 203 uint64_t hash64 = (value1_64 << 32) | value2;
202 204
203 if (sizeof(std::size_t) >= sizeof(uint64)) 205 if (sizeof(std::size_t) >= sizeof(uint64_t))
204 return static_cast<std::size_t>(hash64); 206 return static_cast<std::size_t>(hash64);
205 207
206 uint64 odd_random = 481046412LL << 32 | 1025306955LL; 208 uint64_t odd_random = 481046412LL << 32 | 1025306955LL;
207 uint32 shift_random = 10121U << 16; 209 uint32_t shift_random = 10121U << 16;
208 210
209 hash64 = hash64 * odd_random + shift_random; 211 hash64 = hash64 * odd_random + shift_random;
210 std::size_t high_bits = static_cast<std::size_t>( 212 std::size_t high_bits = static_cast<std::size_t>(
211 hash64 >> (8 * (sizeof(uint64) - sizeof(std::size_t)))); 213 hash64 >> (8 * (sizeof(uint64_t) - sizeof(std::size_t))));
212 return high_bits; 214 return high_bits;
213 } 215 }
214 216
215 // Implement hashing for pairs of up-to 64-bit integer values. 217 // Implement hashing for pairs of up-to 64-bit integer values.
216 // We use the compound integer hash method to produce a 64-bit hash code, by 218 // We use the compound integer hash method to produce a 64-bit hash code, by
217 // breaking the two 64-bit inputs into 4 32-bit values: 219 // breaking the two 64-bit inputs into 4 32-bit values:
218 // http://opendatastructures.org/versions/edition-0.1d/ods-java/node33.html#SECT ION00832000000000000000 220 // http://opendatastructures.org/versions/edition-0.1d/ods-java/node33.html#SECT ION00832000000000000000
219 // Then we reduce our result to 32 bits if required, similar to above. 221 // Then we reduce our result to 32 bits if required, similar to above.
220 inline std::size_t HashInts64(uint64 value1, uint64 value2) { 222 inline std::size_t HashInts64(uint64_t value1, uint64_t value2) {
221 uint32 short_random1 = 842304669U; 223 uint32_t short_random1 = 842304669U;
222 uint32 short_random2 = 619063811U; 224 uint32_t short_random2 = 619063811U;
223 uint32 short_random3 = 937041849U; 225 uint32_t short_random3 = 937041849U;
224 uint32 short_random4 = 3309708029U; 226 uint32_t short_random4 = 3309708029U;
225 227
226 uint32 value1a = static_cast<uint32>(value1 & 0xffffffff); 228 uint32_t value1a = static_cast<uint32_t>(value1 & 0xffffffff);
227 uint32 value1b = static_cast<uint32>((value1 >> 32) & 0xffffffff); 229 uint32_t value1b = static_cast<uint32_t>((value1 >> 32) & 0xffffffff);
228 uint32 value2a = static_cast<uint32>(value2 & 0xffffffff); 230 uint32_t value2a = static_cast<uint32_t>(value2 & 0xffffffff);
229 uint32 value2b = static_cast<uint32>((value2 >> 32) & 0xffffffff); 231 uint32_t value2b = static_cast<uint32_t>((value2 >> 32) & 0xffffffff);
230 232
231 uint64 product1 = static_cast<uint64>(value1a) * short_random1; 233 uint64_t product1 = static_cast<uint64_t>(value1a) * short_random1;
232 uint64 product2 = static_cast<uint64>(value1b) * short_random2; 234 uint64_t product2 = static_cast<uint64_t>(value1b) * short_random2;
233 uint64 product3 = static_cast<uint64>(value2a) * short_random3; 235 uint64_t product3 = static_cast<uint64_t>(value2a) * short_random3;
234 uint64 product4 = static_cast<uint64>(value2b) * short_random4; 236 uint64_t product4 = static_cast<uint64_t>(value2b) * short_random4;
235 237
236 uint64 hash64 = product1 + product2 + product3 + product4; 238 uint64_t hash64 = product1 + product2 + product3 + product4;
237 239
238 if (sizeof(std::size_t) >= sizeof(uint64)) 240 if (sizeof(std::size_t) >= sizeof(uint64_t))
239 return static_cast<std::size_t>(hash64); 241 return static_cast<std::size_t>(hash64);
240 242
241 uint64 odd_random = 1578233944LL << 32 | 194370989LL; 243 uint64_t odd_random = 1578233944LL << 32 | 194370989LL;
242 uint32 shift_random = 20591U << 16; 244 uint32_t shift_random = 20591U << 16;
243 245
244 hash64 = hash64 * odd_random + shift_random; 246 hash64 = hash64 * odd_random + shift_random;
245 std::size_t high_bits = static_cast<std::size_t>( 247 std::size_t high_bits = static_cast<std::size_t>(
246 hash64 >> (8 * (sizeof(uint64) - sizeof(std::size_t)))); 248 hash64 >> (8 * (sizeof(uint64_t) - sizeof(std::size_t))));
247 return high_bits; 249 return high_bits;
248 } 250 }
249 251
250 template<typename T1, typename T2> 252 template<typename T1, typename T2>
251 inline std::size_t HashPair(T1 value1, T2 value2) { 253 inline std::size_t HashPair(T1 value1, T2 value2) {
252 // This condition is expected to be compile-time evaluated and optimised away 254 // This condition is expected to be compile-time evaluated and optimised away
253 // in release builds. 255 // in release builds.
254 if (sizeof(T1) > sizeof(uint32_t) || (sizeof(T2) > sizeof(uint32_t))) 256 if (sizeof(T1) > sizeof(uint32_t) || (sizeof(T2) > sizeof(uint32_t)))
255 return HashInts64(value1, value2); 257 return HashInts64(value1, value2);
256 258
(...skipping 13 matching lines...) Expand all
270 return base::HashPair(value.first, value.second); 272 return base::HashPair(value.first, value.second);
271 } 273 }
272 }; 274 };
273 275
274 } // namespace BASE_HASH_NAMESPACE 276 } // namespace BASE_HASH_NAMESPACE
275 277
276 #undef DEFINE_PAIR_HASH_FUNCTION_START 278 #undef DEFINE_PAIR_HASH_FUNCTION_START
277 #undef DEFINE_PAIR_HASH_FUNCTION_END 279 #undef DEFINE_PAIR_HASH_FUNCTION_END
278 280
279 #endif // BASE_CONTAINERS_HASH_TABLES_H_ 281 #endif // BASE_CONTAINERS_HASH_TABLES_H_
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