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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 #include "base/rand_util.h" | 5 #include "base/rand_util.h" |
6 | 6 |
7 #include <math.h> | 7 #include <math.h> |
8 | 8 |
9 #include <limits> | 9 #include <limits> |
10 | 10 |
11 #include "base/basictypes.h" | 11 #include "base/basictypes.h" |
12 #include "base/logging.h" | 12 #include "base/logging.h" |
13 #include "base/string_util.h" | |
13 | 14 |
14 namespace base { | 15 namespace base { |
15 | 16 |
16 int RandInt(int min, int max) { | 17 int RandInt(int min, int max) { |
17 DCHECK_LE(min, max); | 18 DCHECK_LE(min, max); |
18 | 19 |
19 uint64 range = static_cast<uint64>(max) - min + 1; | 20 uint64 range = static_cast<uint64>(max) - min + 1; |
20 int result = min + static_cast<int>(base::RandGenerator(range)); | 21 int result = min + static_cast<int>(base::RandGenerator(range)); |
21 DCHECK(result >= min && result <= max); | 22 DCHECK(result >= min && result <= max); |
22 return result; | 23 return result; |
(...skipping 11 matching lines...) Expand all Loading... | |
34 double result = ldexp(static_cast<double>(random_bits), -1 * kBits); | 35 double result = ldexp(static_cast<double>(random_bits), -1 * kBits); |
35 DCHECK(result >= 0.0 && result < 1.0); | 36 DCHECK(result >= 0.0 && result < 1.0); |
36 return result; | 37 return result; |
37 } | 38 } |
38 | 39 |
39 uint64 RandGenerator(uint64 max) { | 40 uint64 RandGenerator(uint64 max) { |
40 DCHECK_GT(max, 0ULL); | 41 DCHECK_GT(max, 0ULL); |
41 return base::RandUint64() % max; | 42 return base::RandUint64() % max; |
42 } | 43 } |
43 | 44 |
45 void RandBytes(void* output, size_t output_length) { | |
46 uint64 random_int; | |
47 const char* random_int_bytes = reinterpret_cast<const char*>(&random_int); | |
agl
2011/05/03 14:53:40
nit: you don't need this. memcpy takes a const voi
| |
48 size_t random_int_size = sizeof(random_int); | |
49 for (size_t i = 0; i < output_length; i += random_int_size) { | |
50 random_int = base::RandUint64(); | |
51 size_t copy_count = std::min(output_length - i, random_int_size); | |
52 memcpy(((uint8*)output) + i, random_int_bytes, copy_count); | |
53 } | |
54 } | |
55 | |
44 std::string RandBytesAsString(size_t length) { | 56 std::string RandBytesAsString(size_t length) { |
45 const size_t kBitsPerChar = 8; | 57 std::string result; |
46 const int kCharsPerInt64 = sizeof(uint64)/sizeof(char); | 58 RandBytes(WriteInto(&result, length + 1), length); |
47 | |
48 std::string result(length, '\0'); | |
49 uint64 entropy = 0; | |
50 for (size_t i = 0; i < result.size(); ++i) { | |
51 if (i % kCharsPerInt64 == 0) | |
52 entropy = RandUint64(); | |
53 result[i] = static_cast<char>(entropy); | |
54 entropy >>= kBitsPerChar; | |
55 } | |
56 | |
57 return result; | 59 return result; |
58 } | 60 } |
59 | 61 |
60 } // namespace base | 62 } // namespace base |
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