aboutsummaryrefslogtreecommitdiff
path: root/Src/Winamp/rand.cpp
blob: 8bdea897e2bb36f8f92ff73e88fdf40cbc4f2e8f (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
/** (c) Nullsoft, Inc.         C O N F I D E N T I A L
 ** Filename: 
 ** Project:
 ** Description:
 ** Author: Ben Allison benski@nullsoft.com
 ** Created:
 **/
#include "main.h"
#include "random.h"
#include <wincrypt.h>
/* Period parameters */
#define N 624
#define M 397
#define MATRIX_A 0x9908b0dfUL   /* constant vector a */
#define UPPER_MASK 0x80000000UL /* most significant w-r bits */
#define LOWER_MASK 0x7fffffffUL /* least significant r bits */

static unsigned long mt[N]; /* the array for the state vector  */
static int mti = N + 1; /* mti==N+1 means mt[N] is not initialized */

static CRITICAL_SECTION randCS;
/* initializes mt[N] with a seed */
void init_genrand(unsigned long s)
{
	mt[0] = s & 0xffffffffUL;
	for (mti = 1; mti < N; mti++)
	{
		mt[mti] =
		    (1812433253UL * (mt[mti - 1] ^ (mt[mti - 1] >> 30)) + mti);
		mt[mti] &= 0xffffffffUL;
	}
}

/* initialize by an array with array-length */
/* init_key is the array for initializing keys */
/* key_length is its length */
/* slight change for C++, 2004/2/26 */
void init_by_array(unsigned long init_key[], int key_length)
{
    int i, j, k;
    init_genrand(19650218UL);
    i=1; j=0;
    k = (N>key_length ? N : key_length);
    for (; k; k--) {
        mt[i] = (mt[i] ^ ((mt[i-1] ^ (mt[i-1] >> 30)) * 1664525UL))
          + init_key[j] + j; /* non linear */
        mt[i] &= 0xffffffffUL; /* for WORDSIZE > 32 machines */
        i++; j++;
        if (i>=N) { mt[0] = mt[N-1]; i=1; }
        if (j>=key_length) j=0;
    }
    for (k=N-1; k; k--) {
        mt[i] = (mt[i] ^ ((mt[i-1] ^ (mt[i-1] >> 30)) * 1566083941UL))
          - i; /* non linear */
        mt[i] &= 0xffffffffUL; /* for WORDSIZE > 32 machines */
        i++;
        if (i>=N) { mt[0] = mt[N-1]; i=1; }
    }

    mt[0] = 0x80000000UL; /* MSB is 1; assuring non-zero initial array */ 
}

static const unsigned long mag01[2] = {0x0UL, MATRIX_A};
/* mag01[x] = x * MATRIX_A  for x=0,1 */

/* generates a random number on [0,0xffffffff]-interval */
unsigned long genrand_int32(void)
{
	EnterCriticalSection(&randCS);
	unsigned long y;

	if (mti >= N)
	{ /* generate N words at one time */
		int kk;
		// benski> CUT - because we call init_genrand() as the first thing in WinMain
		//if (mti == N+1)   /* if init_genrand() has not been called, */
		// benski> CUT init_genrand(5489UL); /* a default initial seed is used */

		for (kk = 0;kk < N - M;kk++)
		{
			y = (mt[kk] & UPPER_MASK) | (mt[kk + 1] & LOWER_MASK);
			mt[kk] = mt[kk + M] ^ (y >> 1) ^ mag01[y & 0x1UL];
		}
		for (;kk < N - 1;kk++)
		{
			y = (mt[kk] & UPPER_MASK) | (mt[kk + 1] & LOWER_MASK);
			mt[kk] = mt[kk + (M - N)] ^ (y >> 1) ^ mag01[y & 0x1UL];
		}
		y = (mt[N - 1] & UPPER_MASK) | (mt[0] & LOWER_MASK);
		mt[N - 1] = mt[M - 1] ^ (y >> 1) ^ mag01[y & 0x1UL];

		mti = 0;
	}

	y = mt[mti++];

	LeaveCriticalSection(&randCS);

	/* Tempering */
	y ^= (y >> 11);
	y ^= (y << 7) & 0x9d2c5680UL;
	y ^= (y << 15) & 0xefc60000UL;
	y ^= (y >> 18);
	
	return y;
}

/* generates a random number on [0,0x7fffffff]-interval */
long genrand_int31(void)
{
	return (long)(genrand_int32() >> 1);
}

static HCRYPTPROV GetKeySet()
{
	HCRYPTPROV   hCryptProv;
	LPCSTR UserName = "WinampKeyContainer";  // name of the key container

	if(CryptAcquireContextA(&hCryptProv, UserName, NULL, PROV_RSA_FULL, 0))
	{
		return hCryptProv;
	} 
	else if(CryptAcquireContextA(&hCryptProv, UserName, NULL, PROV_RSA_FULL, CRYPT_NEWKEYSET)) 
	{
		return hCryptProv;
	}
	else
		return 0;
}

Random::Random()
{
	InitializeCriticalSectionAndSpinCount(&randCS, 1000);

	HCRYPTPROV hCryptProv = GetKeySet();
	if (hCryptProv)
	{
		unsigned long seed_data[8];
		if (CryptGenRandom(hCryptProv, sizeof(seed_data), (PBYTE)seed_data)) 
		{
			init_by_array(seed_data, 8);
		}
		CryptReleaseContext(hCryptProv,0);
	}
	else
	{
		LARGE_INTEGER performance_counter;
		QueryPerformanceCounter(&performance_counter);

		unsigned long seed_data[4] = {(unsigned long)performance_counter.HighPart, (unsigned long)performance_counter.LowPart, (unsigned long)GetTickCount64(), (unsigned long)GetCurrentProcessId()};
		init_by_array(seed_data, 4);
	}
}

int warand()
{
	return genrand_int31();
}

float warandf()
{
	return genrand_int32()*(1.0f / 4294967295.0f);
}


RandomGenerator Random::GetFunction()
{
	return warand;
}

UnsignedRandomGenerator Random::GetUnsignedFunction()
{
	return genrand_int32;
}

int Random::GetNumber()
{
	return genrand_int32();
}

int Random::GetPositiveNumber()
{
	return genrand_int31();
}

/* generates a random number on [0,1]-real-interval */
float Random::GetFloat()
{
	return genrand_int32()*(1.0f / 4294967295.0f);
	/* divided by 2^32-1 */
}

/* generates a random number on [0,1)-real-interval */
float Random::GetFloat_LessThanOne()
{
	return genrand_int32()*(1.0f / 4294967296.0f);
	/* divided by 2^32 */
}
/* generates a random number on (0,1)-real-interval */
float Random::GetFloat_LessThanOne_NotZero()
{
	return (((float)genrand_int32()) + 0.5f)*(1.0f / 4294967296.0f);
} // (0-1)

/* generates a random number on [0,1) with 53-bit resolution*/
double Random::GetDouble()
{
	unsigned long a = genrand_int32() >> 5, b = genrand_int32() >> 6;
	return (a*67108864.0 + b)*(1.0 / 9007199254740992.0);
}

#ifdef CBCLASS
#undef CBCLASS
#endif

#define CBCLASS Random
START_DISPATCH;
CB(API_RANDOM_GETFUNCTION, GetFunction)
CB(API_RANDOM_GETFUNCTION_UNSIGNED, GetUnsignedFunction)
CB(API_RANDOM_GETNUMBER, GetNumber)
CB(API_RANDOM_GETPOSITIVENUMBER, GetPositiveNumber)
CB(API_RANDOM_GETFLOAT, GetFloat)
CB(API_RANDOM_GETFLOAT2, GetFloat_LessThanOne)
CB(API_RANDOM_GETFLOAT3, GetFloat_LessThanOne_NotZero)
CB(API_RANDOM_GETDOUBLE, GetDouble)
END_DISPATCH