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
227
228
229
230
231
232
233
|
# Random Number Generator (RNG) implementation based on ChaCha
use ./sysrandom.h
use ./chacha.h
struct chacha_ctx(j0,j1,j2,j3,j4,j5,j6,j7,j8,j9,j10,j11,j12,j13,j14,j15:Int32; extern, secret)
func from_seed(seed:[Byte]=[] -> chacha_ctx)
return C_code:chacha_ctx(
chacha_ctx ctx;
uint8_t seed_bytes[KEYSZ + IVSZ] = {};
for (int64_t i = 0; i < (int64_t)sizeof(seed_bytes); i++)
seed_bytes[i] = i < @seed.length ? *(uint8_t*)(@seed.data + i*@seed.stride) : 0;
chacha_keysetup(&ctx, seed_bytes);
chacha_ivsetup(&ctx, seed_bytes + KEYSZ);
ctx
)
random := RandomNumberGenerator.new()
func _os_random_bytes(count:Int64 -> [Byte])
return C_code:[Byte](
uint8_t *random_bytes = GC_MALLOC_ATOMIC(@count);
getrandom(random_bytes, @count, 0);
(Array_t){.length=@count, .data=random_bytes, .stride=1, .atomic=1}
)
struct RandomNumberGenerator(_chacha:chacha_ctx, _random_bytes:[Byte]=[]; secret)
func new(seed:[Byte]?=none, -> @RandomNumberGenerator)
ctx := chacha_ctx.from_seed(seed or _os_random_bytes(40))
return @RandomNumberGenerator(ctx, [])
func _rekey(rng:&RandomNumberGenerator)
rng._random_bytes = C_code:[Byte](
Byte_t new_keystream[KEYSZ + IVSZ] = {};
// Fill the buffer with the keystream
chacha_encrypt_bytes(&@rng->_chacha, new_keystream, new_keystream, sizeof(new_keystream));
// Immediately reinitialize for backtracking resistance
chacha_keysetup(&@rng->_chacha, new_keystream);
chacha_ivsetup(&@rng->_chacha, new_keystream + KEYSZ);
Array_t new_bytes = (Array_t){.data=GC_MALLOC_ATOMIC(1024), .length=1024, .stride=1, .atomic=1};
memset(new_bytes.data, 0, new_bytes.length);
chacha_encrypt_bytes(&@rng->_chacha, new_bytes.data, new_bytes.data, new_bytes.length);
new_bytes
)
func _fill_bytes(rng:&RandomNumberGenerator, dest:&Memory, needed:Int64)
C_code {
while (@needed > 0) {
if (@rng->_random_bytes.length == 0)
@(rng._rekey());
assert(@rng->_random_bytes.stride == 1);
int64_t batch_size = MIN(@needed, @rng->_random_bytes.length);
uint8_t *batch_src = @rng->_random_bytes.data;
memcpy(@dest, batch_src, batch_size);
memset(batch_src, 0, batch_size);
@rng->_random_bytes.data += batch_size;
@rng->_random_bytes.length -= batch_size;
@dest += batch_size;
@needed -= batch_size;
}
}
func bytes(rng:&RandomNumberGenerator, count:Int -> [Byte])
count64 := Int64(count)
buf := C_code:@Memory(GC_MALLOC_ATOMIC(@count64))
rng._fill_bytes(buf, count64)
return C_code:[Byte]((Array_t){.data=@buf, .stride=1, .atomic=1, .length=@count64})
func byte(rng:&RandomNumberGenerator -> Byte)
byte : &Byte
rng._fill_bytes(byte, 1)
return byte[]
func bool(rng:&RandomNumberGenerator, probability=0.5 -> Bool)
if probability == 0.5
return rng.byte() < 0x80
else
return rng.num(0., 1.) < 0.5
func int64(rng:&RandomNumberGenerator, min=Int64.min, max=Int64.max -> Int64)
fail("Random minimum value $min is larger than the maximum value $max") if min > max
return min if min == max
random_int64 : &Int64
rng._fill_bytes(random_int64, 8)
if min == Int64.min and max == Int64.max
return random_int64
return C_code:Int64(
uint64_t range = (uint64_t)@max - (uint64_t)@min + 1;
uint64_t min_r = -range % range;
uint64_t r;
@random_int64 = &r;
for (;;) {
@(rng._fill_bytes(random_int64, 8));
if (r >= min_r) break;
}
(int64_t)((uint64_t)@min + (r % range))
)
func int32(rng:&RandomNumberGenerator, min=Int32.min, max=Int32.max -> Int32)
fail("Random minimum value $min is larger than the maximum value $max") if min > max
return min if min == max
random_int32 : &Int32
rng._fill_bytes(random_int32, 8)
if min == Int32.min and max == Int32.max
return random_int32
return C_code:Int32(
uint32_t range = (uint32_t)@max - (uint32_t)@min + 1;
uint32_t min_r = -range % range;
uint32_t r;
@random_int32 = &r;
for (;;) {
@(rng._fill_bytes(random_int32, 8));
if (r >= min_r) break;
}
(int32_t)((uint32_t)@min + (r % range))
)
func int16(rng:&RandomNumberGenerator, min=Int16.min, max=Int16.max -> Int16)
fail("Random minimum value $min is larger than the maximum value $max") if min > max
return min if min == max
random_int16 : &Int16
rng._fill_bytes(random_int16, 8)
if min == Int16.min and max == Int16.max
return random_int16
return C_code:Int16(
uint16_t range = (uint16_t)@max - (uint16_t)@min + 1;
uint16_t min_r = -range % range;
uint16_t r;
@random_int16 = &r;
for (;;) {
@(rng._fill_bytes(random_int16, 8));
if (r >= min_r) break;
}
(int16_t)((uint16_t)@min + (r % range))
)
func int8(rng:&RandomNumberGenerator, min=Int8.min, max=Int8.max -> Int8)
fail("Random minimum value $min is larger than the maximum value $max") if min > max
return min if min == max
random_int8 : &Int8
rng._fill_bytes(random_int8, 8)
if min == Int8.min and max == Int8.max
return random_int8
return C_code:Int8(
uint8_t range = (uint8_t)@max - (uint8_t)@min + 1;
uint8_t min_r = -range % range;
uint8_t r;
@random_int8 = &r;
for (;;) {
@(rng._fill_bytes(random_int8, 8));
if (r >= min_r) break;
}
(int8_t)((uint8_t)@min + (r % range))
)
func num(rng:&RandomNumberGenerator, min=0., max=1. -> Num)
num_buf : &Num
return C_code:Num(
if (@min > @max) fail("Random minimum value (", @min, ") is larger than the maximum value (", @max, ")");
if (@min == @max) return @min;
union {
Num_t num;
uint64_t bits;
} r = {.bits=0}, one = {.num=1.0};
@num_buf = &r.num;
@(rng._fill_bytes(num_buf, 8));
// Set r.num to 1.<random-bits>
r.bits &= ~(0xFFFULL << 52);
r.bits |= (one.bits & (0xFFFULL << 52));
r.num -= 1.0;
(@min == 0.0 && @max == 1.0) ? r.num : ((1.0-r.num)*@min + r.num*@max)
)
func num32(rng:&RandomNumberGenerator, min=Num32(0.), max=Num32(1.) -> Num32)
return Num32(rng.num(Num(min), Num(max)))
func int(rng:&RandomNumberGenerator, min:Int, max:Int -> Int)
return C_code:Int(
if (likely(((@min.small & @max.small) & 1) != 0)) {
int32_t r = @(rng.int32(Int32(min), Int32(max)));
return I_small(r);
}
int32_t cmp = @(min <> max);
if (cmp > 0)
fail("Random minimum value (", @min, ") is larger than the maximum value (", @max, ")");
if (cmp == 0) return @min;
mpz_t range_size;
mpz_init_set_int(range_size, @max);
if (@min.small & 1) {
mpz_t min_mpz;
mpz_init_set_si(min_mpz, @min.small >> 2);
mpz_sub(range_size, range_size, min_mpz);
} else {
mpz_sub(range_size, range_size, *@min.big);
}
gmp_randstate_t gmp_rng;
gmp_randinit_default(gmp_rng);
int64_t seed = @(rng.int64());
gmp_randseed_ui(gmp_rng, (unsigned long)seed);
mpz_t r;
mpz_init(r);
mpz_urandomm(r, gmp_rng, range_size);
gmp_randclear(gmp_rng);
Int$plus(@min, Int$from_mpz(r))
)
func main()
>> rng := RandomNumberGenerator.new()
>> rng.num()
>> rng.num()
>> rng.num()
>> rng.num(0, 100)
>> rng.byte()
>> rng.bytes(20)
# >> rng.int(1, 100)
# >> rng.int(1, 100)
# >> rng.int(1, 100)
# >> rng.int(1, 100)
|
