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Diffstat (limited to 'lib/random/random.tm')
| -rw-r--r-- | lib/random/random.tm | 233 |
1 files changed, 233 insertions, 0 deletions
diff --git a/lib/random/random.tm b/lib/random/random.tm new file mode 100644 index 00000000..14b68d7f --- /dev/null +++ b/lib/random/random.tm @@ -0,0 +1,233 @@ +# 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); + (List_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); + List_t new_bytes = (List_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]((List_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) |