Chromium Code Reviews
chromiumcodereview-hr@appspot.gserviceaccount.com (chromiumcodereview-hr) | Please choose your nickname with Settings | Help | Chromium Project | Gerrit Changes | Sign out
(169)

Side by Side Diff: webrtc/base/random.h

Issue 2877023002: Move webrtc/{base => rtc_base} (Closed)
Patch Set: update presubmit.py and DEPS include rules Created 3 years, 5 months ago
Use n/p to move between diff chunks; N/P to move between comments. Draft comments are only viewable by you.
Jump to:
View unified diff | Download patch
« no previous file with comments | « webrtc/base/race_checker.cc ('k') | webrtc/base/random.cc » ('j') | no next file with comments »
Toggle Intra-line Diffs ('i') | Expand Comments ('e') | Collapse Comments ('c') | Show Comments Hide Comments ('s')
OLDNEW
1 /* 1 /*
2 * Copyright (c) 2015 The WebRTC project authors. All Rights Reserved. 2 * Copyright (c) 2015 The WebRTC project authors. All Rights Reserved.
3 * 3 *
4 * Use of this source code is governed by a BSD-style license 4 * Use of this source code is governed by a BSD-style license
5 * that can be found in the LICENSE file in the root of the source 5 * that can be found in the LICENSE file in the root of the source
6 * tree. An additional intellectual property rights grant can be found 6 * tree. An additional intellectual property rights grant can be found
7 * in the file PATENTS. All contributing project authors may 7 * in the file PATENTS. All contributing project authors may
8 * be found in the AUTHORS file in the root of the source tree. 8 * be found in the AUTHORS file in the root of the source tree.
9 */ 9 */
10 10
11 #ifndef WEBRTC_BASE_RANDOM_H_ 11 #ifndef WEBRTC_BASE_RANDOM_H_
12 #define WEBRTC_BASE_RANDOM_H_ 12 #define WEBRTC_BASE_RANDOM_H_
13 13
14 #include <limits>
15 14
16 #include "webrtc/typedefs.h" 15 // This header is deprecated and is just left here temporarily during
17 #include "webrtc/base/constructormagic.h" 16 // refactoring. See https://bugs.webrtc.org/7634 for more details.
18 #include "webrtc/base/checks.h" 17 #include "webrtc/rtc_base/random.h"
19
20 namespace webrtc {
21
22 class Random {
23 public:
24 // TODO(tommi): Change this so that the seed can be initialized internally,
25 // e.g. by offering two ways of constructing or offer a static method that
26 // returns a seed that's suitable for initialization.
27 // The problem now is that callers are calling clock_->TimeInMicroseconds()
28 // which calls TickTime::Now().Ticks(), which can return a very low value on
29 // Mac and can result in a seed of 0 after conversion to microseconds.
30 // Besides the quality of the random seed being poor, this also requires
31 // the client to take on extra dependencies to generate a seed.
32 // If we go for a static seed generator in Random, we can use something from
33 // webrtc/base and make sure that it works the same way across platforms.
34 // See also discussion here: https://codereview.webrtc.org/1623543002/
35 explicit Random(uint64_t seed);
36
37 // Return pseudo-random integer of the specified type.
38 // We need to limit the size to 32 bits to keep the output close to uniform.
39 template <typename T>
40 T Rand() {
41 static_assert(std::numeric_limits<T>::is_integer &&
42 std::numeric_limits<T>::radix == 2 &&
43 std::numeric_limits<T>::digits <= 32,
44 "Rand is only supported for built-in integer types that are "
45 "32 bits or smaller.");
46 return static_cast<T>(NextOutput());
47 }
48
49 // Uniformly distributed pseudo-random number in the interval [0, t].
50 uint32_t Rand(uint32_t t);
51
52 // Uniformly distributed pseudo-random number in the interval [low, high].
53 uint32_t Rand(uint32_t low, uint32_t high);
54
55 // Uniformly distributed pseudo-random number in the interval [low, high].
56 int32_t Rand(int32_t low, int32_t high);
57
58 // Normal Distribution.
59 double Gaussian(double mean, double standard_deviation);
60
61 // Exponential Distribution.
62 double Exponential(double lambda);
63
64 private:
65 // Outputs a nonzero 64-bit random number.
66 uint64_t NextOutput() {
67 state_ ^= state_ >> 12;
68 state_ ^= state_ << 25;
69 state_ ^= state_ >> 27;
70 RTC_DCHECK(state_ != 0x0ULL);
71 return state_ * 2685821657736338717ull;
72 }
73
74 uint64_t state_;
75
76 RTC_DISALLOW_IMPLICIT_CONSTRUCTORS(Random);
77 };
78
79 // Return pseudo-random number in the interval [0.0, 1.0).
80 template <>
81 float Random::Rand<float>();
82
83 // Return pseudo-random number in the interval [0.0, 1.0).
84 template <>
85 double Random::Rand<double>();
86
87 // Return pseudo-random boolean value.
88 template <>
89 bool Random::Rand<bool>();
90
91 } // namespace webrtc
92 18
93 #endif // WEBRTC_BASE_RANDOM_H_ 19 #endif // WEBRTC_BASE_RANDOM_H_
OLDNEW
« no previous file with comments | « webrtc/base/race_checker.cc ('k') | webrtc/base/random.cc » ('j') | no next file with comments »

Powered by Google App Engine
This is Rietveld 408576698