OpenShot Audio Library | OpenShotAudio 0.4.0
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juce_Random.cpp
1/*
2 ==============================================================================
3
4 This file is part of the JUCE library.
5 Copyright (c) 2022 - Raw Material Software Limited
6
7 JUCE is an open source library subject to commercial or open-source
8 licensing.
9
10 The code included in this file is provided under the terms of the ISC license
11 http://www.isc.org/downloads/software-support-policy/isc-license. Permission
12 To use, copy, modify, and/or distribute this software for any purpose with or
13 without fee is hereby granted provided that the above copyright notice and
14 this permission notice appear in all copies.
15
16 JUCE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES, WHETHER
17 EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR PURPOSE, ARE
18 DISCLAIMED.
19
20 ==============================================================================
21*/
22
23namespace juce
24{
25
26Random::Random (int64 seedValue) noexcept : seed (seedValue)
27{
28}
29
30Random::Random() : seed (1)
31{
33}
34
35void Random::setSeed (const int64 newSeed) noexcept
36{
37 if (this == &getSystemRandom())
38 {
39 // Resetting the system Random risks messing up
40 // JUCE's internal state. If you need a predictable
41 // stream of random numbers you should use a local
42 // Random object.
43 jassertfalse;
44 return;
45 }
46
47 seed = newSeed;
48}
49
50void Random::combineSeed (const int64 seedValue) noexcept
51{
52 seed ^= nextInt64() ^ seedValue;
53}
54
56{
57 static std::atomic<int64> globalSeed { 0 };
58
59 combineSeed (globalSeed ^ (int64) (pointer_sized_int) this);
64 globalSeed ^= seed;
65}
66
68{
69 static Random sysRand;
70 return sysRand;
71}
72
73//==============================================================================
74int Random::nextInt() noexcept
75{
76 seed = (int64) (((((uint64) seed) * 0x5deece66dLL) + 11) & 0xffffffffffffLL);
77
78 return (int) (seed >> 16);
79}
80
81int Random::nextInt (const int maxValue) noexcept
82{
83 jassert (maxValue > 0);
84 return (int) ((((unsigned int) nextInt()) * (uint64) maxValue) >> 32);
85}
86
87int Random::nextInt (Range<int> range) noexcept
88{
89 return range.getStart() + nextInt (range.getLength());
90}
91
92int64 Random::nextInt64() noexcept
93{
94 return (int64) ((((uint64) (unsigned int) nextInt()) << 32) | (uint64) (unsigned int) nextInt());
95}
96
97bool Random::nextBool() noexcept
98{
99 return (nextInt() & 0x40000000) != 0;
100}
101
102float Random::nextFloat() noexcept
103{
104 auto result = static_cast<float> (static_cast<uint32> (nextInt()))
105 / (static_cast<float> (std::numeric_limits<uint32>::max()) + 1.0f);
106 return jmin (result, 1.0f - std::numeric_limits<float>::epsilon());
107}
108
109double Random::nextDouble() noexcept
110{
111 return static_cast<uint32> (nextInt()) / (std::numeric_limits<uint32>::max() + 1.0);
112}
113
115{
116 BigInteger n;
117
118 do
119 {
120 fillBitsRandomly (n, 0, maximumValue.getHighestBit() + 1);
121 }
122 while (n >= maximumValue);
123
124 return n;
125}
126
127void Random::fillBitsRandomly (void* const buffer, size_t bytes)
128{
129 int* d = static_cast<int*> (buffer);
130
131 for (; bytes >= sizeof (int); bytes -= sizeof (int))
132 *d++ = nextInt();
133
134 if (bytes > 0)
135 {
136 const int lastBytes = nextInt();
137 memcpy (d, &lastBytes, bytes);
138 }
139}
140
141void Random::fillBitsRandomly (BigInteger& arrayToChange, int startBit, int numBits)
142{
143 arrayToChange.setBit (startBit + numBits - 1, true); // to force the array to pre-allocate space
144
145 while ((startBit & 31) != 0 && numBits > 0)
146 {
147 arrayToChange.setBit (startBit++, nextBool());
148 --numBits;
149 }
150
151 while (numBits >= 32)
152 {
153 arrayToChange.setBitRangeAsInt (startBit, 32, (unsigned int) nextInt());
154 startBit += 32;
155 numBits -= 32;
156 }
157
158 while (--numBits >= 0)
159 arrayToChange.setBit (startBit + numBits, nextBool());
160}
161
162
163//==============================================================================
164//==============================================================================
165#if JUCE_UNIT_TESTS
166
167class RandomTests final : public UnitTest
168{
169public:
170 RandomTests()
171 : UnitTest ("Random", UnitTestCategories::maths)
172 {}
173
174 void runTest() override
175 {
176 beginTest ("Random");
177
178 Random r = getRandom();
179
180 for (int i = 2000; --i >= 0;)
181 {
182 expect (r.nextDouble() >= 0.0 && r.nextDouble() < 1.0);
183 expect (r.nextFloat() >= 0.0f && r.nextFloat() < 1.0f);
184 expect (r.nextInt (5) >= 0 && r.nextInt (5) < 5);
185 expect (r.nextInt (1) == 0);
186
187 int n = r.nextInt (50) + 1;
188 expect (r.nextInt (n) >= 0 && r.nextInt (n) < n);
189
190 n = r.nextInt (0x7ffffffe) + 1;
191 expect (r.nextInt (n) >= 0 && r.nextInt (n) < n);
192 }
193 }
194};
195
196static RandomTests randomTests;
197
198#endif
199
200} // namespace juce
int getHighestBit() const noexcept
BigInteger & setBitRangeAsInt(int startBit, int numBits, uint32 valueToSet)
BigInteger & setBit(int bitNumber)
float nextFloat() noexcept
void fillBitsRandomly(void *bufferToFill, size_t sizeInBytes)
bool nextBool() noexcept
void setSeedRandomly()
void combineSeed(int64 seedValue) noexcept
int nextInt() noexcept
int64 nextInt64() noexcept
void setSeed(int64 newSeed) noexcept
double nextDouble() noexcept
BigInteger nextLargeNumber(const BigInteger &maximumValue)
static Random & getSystemRandom() noexcept
static int64 getHighResolutionTicks() noexcept
static int64 currentTimeMillis() noexcept
static int64 getHighResolutionTicksPerSecond() noexcept
static uint32 getMillisecondCounter() noexcept