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1 // Copyright 2013 the V8 project authors. All rights reserved. | 1 // Copyright 2013 the V8 project 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 #ifndef V8_BASE_UTILS_RANDOM_NUMBER_GENERATOR_H_ | 5 #ifndef V8_BASE_UTILS_RANDOM_NUMBER_GENERATOR_H_ |
6 #define V8_BASE_UTILS_RANDOM_NUMBER_GENERATOR_H_ | 6 #define V8_BASE_UTILS_RANDOM_NUMBER_GENERATOR_H_ |
7 | 7 |
8 #include "src/base/macros.h" | 8 #include "src/base/macros.h" |
9 | 9 |
10 namespace v8 { | 10 namespace v8 { |
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67 // (approximately) uniformly from the range 0.0 (inclusive) to 1.0 | 67 // (approximately) uniformly from the range 0.0 (inclusive) to 1.0 |
68 // (exclusive), is pseudorandomly generated and returned. | 68 // (exclusive), is pseudorandomly generated and returned. |
69 double NextDouble() WARN_UNUSED_RESULT; | 69 double NextDouble() WARN_UNUSED_RESULT; |
70 | 70 |
71 // Fills the elements of a specified array of bytes with random numbers. | 71 // Fills the elements of a specified array of bytes with random numbers. |
72 void NextBytes(void* buffer, size_t buflen); | 72 void NextBytes(void* buffer, size_t buflen); |
73 | 73 |
74 // Override the current ssed. | 74 // Override the current ssed. |
75 void SetSeed(int64_t seed); | 75 void SetSeed(int64_t seed); |
76 | 76 |
77 int64_t initial_seed() const { return initial_seed_; } | |
78 | |
79 private: | 77 private: |
80 static const int64_t kMultiplier = V8_2PART_UINT64_C(0x5, deece66d); | 78 static const int64_t kMultiplier = V8_2PART_UINT64_C(0x5, deece66d); |
81 static const int64_t kAddend = 0xb; | 79 static const int64_t kAddend = 0xb; |
82 static const int64_t kMask = V8_2PART_UINT64_C(0xffff, ffffffff); | 80 static const int64_t kMask = V8_2PART_UINT64_C(0xffff, ffffffff); |
83 | 81 |
84 int Next(int bits) WARN_UNUSED_RESULT; | 82 int Next(int bits) WARN_UNUSED_RESULT; |
85 | 83 |
86 int64_t initial_seed_; | |
87 int64_t seed_; | 84 int64_t seed_; |
88 }; | 85 }; |
89 | 86 |
90 } } // namespace v8::base | 87 } } // namespace v8::base |
91 | 88 |
92 #endif // V8_BASE_UTILS_RANDOM_NUMBER_GENERATOR_H_ | 89 #endif // V8_BASE_UTILS_RANDOM_NUMBER_GENERATOR_H_ |
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