diff options
Diffstat (limited to 'v_windows/v/old/vlib/rand/sys')
| -rw-r--r-- | v_windows/v/old/vlib/rand/sys/system_rng.c.v | 275 | ||||
| -rw-r--r-- | v_windows/v/old/vlib/rand/sys/system_rng.js.v | 15 | ||||
| -rw-r--r-- | v_windows/v/old/vlib/rand/sys/system_rng_test.v | 354 |
3 files changed, 644 insertions, 0 deletions
diff --git a/v_windows/v/old/vlib/rand/sys/system_rng.c.v b/v_windows/v/old/vlib/rand/sys/system_rng.c.v new file mode 100644 index 0000000..f1c701d --- /dev/null +++ b/v_windows/v/old/vlib/rand/sys/system_rng.c.v @@ -0,0 +1,275 @@ +// Copyright (c) 2019-2021 Alexander Medvednikov. All rights reserved. +// Use of this source code is governed by an MIT license +// that can be found in the LICENSE file. +module sys + +import math.bits +import rand.seed +import rand.constants + +// Implementation note: +// ==================== +// C.rand returns a pseudorandom integer from 0 (inclusive) to C.RAND_MAX (exclusive) +// C.rand() is okay to use within its defined range. +// (See: https://web.archive.org/web/20180801210127/http://eternallyconfuzzled.com/arts/jsw_art_rand.aspx) +// The problem is, this value varies with the libc implementation. On windows, +// for example, RAND_MAX is usually a measly 32767, whereas on (newer) linux it's generally +// 2147483647. The repetition period also varies wildly. In order to provide more entropy +// without altering the underlying algorithm too much, this implementation simply +// requests for more random bits until the necessary width for the integers is achieved. +const ( + rand_limit = u64(C.RAND_MAX) + rand_bitsize = bits.len_64(rand_limit) + u32_iter_count = calculate_iterations_for(32) + u64_iter_count = calculate_iterations_for(64) +) + +fn calculate_iterations_for(bits int) int { + base := bits / sys.rand_bitsize + extra := if bits % sys.rand_bitsize == 0 { 0 } else { 1 } + return base + extra +} + +// SysRNG is the PRNG provided by default in the libc implementiation that V uses. +pub struct SysRNG { +mut: + seed u32 = seed.time_seed_32() +} + +// r.seed() sets the seed of the accepting SysRNG to the given data. +pub fn (mut r SysRNG) seed(seed_data []u32) { + if seed_data.len != 1 { + eprintln('SysRNG needs one 32-bit unsigned integer as the seed.') + exit(1) + } + r.seed = seed_data[0] + C.srand(r.seed) +} + +// r.default_rand() exposes the default behavior of the system's RNG +// (equivalent to calling C.rand()). Recommended for testing/comparison +// b/w V and other languages using libc and not for regular use. +// This is also a one-off feature of SysRNG, similar to the global seed +// situation. Other generators will not have this. +[inline] +pub fn (r SysRNG) default_rand() int { + return C.rand() +} + +// r.u32() returns a pseudorandom u32 value less than 2^32 +[inline] +pub fn (r SysRNG) u32() u32 { + mut result := u32(C.rand()) + for i in 1 .. sys.u32_iter_count { + result = result ^ (u32(C.rand()) << (sys.rand_bitsize * i)) + } + return result +} + +// r.u64() returns a pseudorandom u64 value less than 2^64 +[inline] +pub fn (r SysRNG) u64() u64 { + mut result := u64(C.rand()) + for i in 1 .. sys.u64_iter_count { + result = result ^ (u64(C.rand()) << (sys.rand_bitsize * i)) + } + return result +} + +// r.u32n(max) returns a pseudorandom u32 value that is guaranteed to be less than max +[inline] +pub fn (r SysRNG) u32n(max u32) u32 { + if max == 0 { + eprintln('max must be positive integer') + exit(1) + } + // Owing to the pigeon-hole principle, we can't simply do + // val := rng.u32() % max. + // It'll wreck the properties of the distribution unless + // max evenly divides 2^32. So we divide evenly to + // the closest power of two. Then we loop until we find + // an int in the required range + bit_len := bits.len_32(max) + if bit_len == 32 { + for { + value := r.u32() + if value < max { + return value + } + } + } else { + mask := (u32(1) << (bit_len + 1)) - 1 + for { + value := r.u32() & mask + if value < max { + return value + } + } + } + return u32(0) +} + +// r.u64n(max) returns a pseudorandom u64 value that is guaranteed to be less than max +[inline] +pub fn (r SysRNG) u64n(max u64) u64 { + if max == 0 { + eprintln('max must be positive integer') + exit(1) + } + // Similar procedure for u64s + bit_len := bits.len_64(max) + if bit_len == 64 { + for { + value := r.u64() + if value < max { + return value + } + } + } else { + mask := (u64(1) << (bit_len + 1)) - 1 + for { + value := r.u64() & mask + if value < max { + return value + } + } + } + return u64(0) +} + +// r.u32n(min, max) returns a pseudorandom u32 value that is guaranteed to be in [min, max) +[inline] +pub fn (r SysRNG) u32_in_range(min u32, max u32) u32 { + if max <= min { + eprintln('max must be greater than min') + exit(1) + } + return min + r.u32n(max - min) +} + +// r.u64n(min, max) returns a pseudorandom u64 value that is guaranteed to be in [min, max) +[inline] +pub fn (r SysRNG) u64_in_range(min u64, max u64) u64 { + if max <= min { + eprintln('max must be greater than min') + exit(1) + } + return min + r.u64n(max - min) +} + +// r.int() returns a pseudorandom 32-bit int (which may be negative) +[inline] +pub fn (r SysRNG) int() int { + return int(r.u32()) +} + +// r.i64() returns a pseudorandom 64-bit i64 (which may be negative) +[inline] +pub fn (r SysRNG) i64() i64 { + return i64(r.u64()) +} + +// r.int31() returns a pseudorandom 31-bit int which is non-negative +[inline] +pub fn (r SysRNG) int31() int { + return int(r.u32() & constants.u31_mask) // Set the 32nd bit to 0. +} + +// r.int63() returns a pseudorandom 63-bit int which is non-negative +[inline] +pub fn (r SysRNG) int63() i64 { + return i64(r.u64() & constants.u63_mask) // Set the 64th bit to 0. +} + +// r.intn(max) returns a pseudorandom int that lies in [0, max) +[inline] +pub fn (r SysRNG) intn(max int) int { + if max <= 0 { + eprintln('max has to be positive.') + exit(1) + } + return int(r.u32n(u32(max))) +} + +// r.i64n(max) returns a pseudorandom i64 that lies in [0, max) +[inline] +pub fn (r SysRNG) i64n(max i64) i64 { + if max <= 0 { + eprintln('max has to be positive.') + exit(1) + } + return i64(r.u64n(u64(max))) +} + +// r.int_in_range(min, max) returns a pseudorandom int that lies in [min, max) +[inline] +pub fn (r SysRNG) int_in_range(min int, max int) int { + if max <= min { + eprintln('max must be greater than min') + exit(1) + } + // This supports negative ranges like [-10, -5) because the difference is positive + return min + r.intn(max - min) +} + +// r.i64_in_range(min, max) returns a pseudorandom i64 that lies in [min, max) +[inline] +pub fn (r SysRNG) i64_in_range(min i64, max i64) i64 { + if max <= min { + eprintln('max must be greater than min') + exit(1) + } + return min + r.i64n(max - min) +} + +// r.f32() returns a pseudorandom f32 value between 0.0 (inclusive) and 1.0 (exclusive) i.e [0, 1) +[inline] +pub fn (r SysRNG) f32() f32 { + return f32(r.u32()) / constants.max_u32_as_f32 +} + +// r.f64() returns a pseudorandom f64 value between 0.0 (inclusive) and 1.0 (exclusive) i.e [0, 1) +[inline] +pub fn (r SysRNG) f64() f64 { + return f64(r.u64()) / constants.max_u64_as_f64 +} + +// r.f32n() returns a pseudorandom f32 value in [0, max) +[inline] +pub fn (r SysRNG) f32n(max f32) f32 { + if max <= 0 { + eprintln('max has to be positive.') + exit(1) + } + return r.f32() * max +} + +// r.f64n() returns a pseudorandom f64 value in [0, max) +[inline] +pub fn (r SysRNG) f64n(max f64) f64 { + if max <= 0 { + eprintln('max has to be positive.') + exit(1) + } + return r.f64() * max +} + +// r.f32_in_range(min, max) returns a pseudorandom f32 that lies in [min, max) +[inline] +pub fn (r SysRNG) f32_in_range(min f32, max f32) f32 { + if max <= min { + eprintln('max must be greater than min') + exit(1) + } + return min + r.f32n(max - min) +} + +// r.i64_in_range(min, max) returns a pseudorandom i64 that lies in [min, max) +[inline] +pub fn (r SysRNG) f64_in_range(min f64, max f64) f64 { + if max <= min { + eprintln('max must be greater than min') + exit(1) + } + return min + r.f64n(max - min) +} diff --git a/v_windows/v/old/vlib/rand/sys/system_rng.js.v b/v_windows/v/old/vlib/rand/sys/system_rng.js.v new file mode 100644 index 0000000..496794d --- /dev/null +++ b/v_windows/v/old/vlib/rand/sys/system_rng.js.v @@ -0,0 +1,15 @@ +// Copyright (c) 2019-2021 Alexander Medvednikov. All rights reserved. +// Use of this source code is governed by an MIT license +// that can be found in the LICENSE file. +module sys + +// Until there's a portable, JS has a seeded way to produce random numbers +// and not just Math.random(), use any of the existing implementations +// as the System's RNG +type SysRNG = WyRandRNG + +// In the JS version, we simply return the same int as is normally generated. +[inline] +pub fn (r SysRNG) default_rand() int { + return r.int() +} diff --git a/v_windows/v/old/vlib/rand/sys/system_rng_test.v b/v_windows/v/old/vlib/rand/sys/system_rng_test.v new file mode 100644 index 0000000..638ed10 --- /dev/null +++ b/v_windows/v/old/vlib/rand/sys/system_rng_test.v @@ -0,0 +1,354 @@ +import math +import rand.sys + +const ( + range_limit = 40 + value_count = 1000 + seeds = [u32(42), 256] +) + +const ( + sample_size = 1000 + stats_epsilon = 0.05 + inv_sqrt_12 = 1.0 / math.sqrt(12) +) + +fn get_n_randoms(n int, r sys.SysRNG) []int { + mut ints := []int{cap: n} + for _ in 0 .. n { + ints << r.int() + } + return ints +} + +fn test_sys_rng_reproducibility() { + // Note that C.srand() sets the seed globally. + // So the order of seeding matters. It is recommended + // to obtain all necessary data first, then set the + // seed for another batch of data. + for seed in seeds { + seed_data := [seed] + mut r1 := sys.SysRNG{} + mut r2 := sys.SysRNG{} + r1.seed(seed_data) + ints1 := get_n_randoms(value_count, r1) + r2.seed(seed_data) + ints2 := get_n_randoms(value_count, r2) + assert ints1 == ints2 + } +} + +// TODO: use the `in` syntax and remove this function +// after generics has been completely implemented +fn found(value u64, arr []u64) bool { + for item in arr { + if value == item { + return true + } + } + return false +} + +fn test_sys_rng_variability() { + // If this test fails and if it is certainly not the implementation + // at fault, try changing the seed values. Repeated values are + // improbable but not impossible. + for seed in seeds { + seed_data := [seed] + mut rng := sys.SysRNG{} + rng.seed(seed_data) + mut values := []u64{cap: value_count} + for i in 0 .. value_count { + value := rng.u64() + assert !found(value, values) + assert values.len == i + values << value + } + } +} + +fn check_uniformity_u64(rng sys.SysRNG, range u64) { + range_f64 := f64(range) + expected_mean := range_f64 / 2.0 + mut variance := 0.0 + for _ in 0 .. sample_size { + diff := f64(rng.u64n(range)) - expected_mean + variance += diff * diff + } + variance /= sample_size - 1 + sigma := math.sqrt(variance) + expected_sigma := range_f64 * inv_sqrt_12 + error := (sigma - expected_sigma) / expected_sigma + assert math.abs(error) < stats_epsilon +} + +fn test_sys_rng_uniformity_u64() { + // This assumes that C.rand() produces uniform results to begin with. + // If the failure persists, report an issue on GitHub + ranges := [14019545, 80240, 130] + for seed in seeds { + seed_data := [seed] + mut rng := sys.SysRNG{} + rng.seed(seed_data) + for range in ranges { + check_uniformity_u64(rng, u64(range)) + } + } +} + +fn check_uniformity_f64(rng sys.SysRNG) { + expected_mean := 0.5 + mut variance := 0.0 + for _ in 0 .. sample_size { + diff := rng.f64() - expected_mean + variance += diff * diff + } + variance /= sample_size - 1 + sigma := math.sqrt(variance) + expected_sigma := inv_sqrt_12 + error := (sigma - expected_sigma) / expected_sigma + assert math.abs(error) < stats_epsilon +} + +fn test_sys_rng_uniformity_f64() { + // The f64 version + for seed in seeds { + seed_data := [seed] + mut rng := sys.SysRNG{} + rng.seed(seed_data) + check_uniformity_f64(rng) + } +} + +fn test_sys_rng_u32n() { + max := u32(16384) + for seed in seeds { + seed_data := [seed] + mut rng := sys.SysRNG{} + rng.seed(seed_data) + for _ in 0 .. range_limit { + value := rng.u32n(max) + assert value >= 0 + assert value < max + } + } +} + +fn test_sys_rng_u64n() { + max := u64(379091181005) + for seed in seeds { + seed_data := [seed] + mut rng := sys.SysRNG{} + rng.seed(seed_data) + for _ in 0 .. range_limit { + value := rng.u64n(max) + assert value >= 0 + assert value < max + } + } +} + +fn test_sys_rng_u32_in_range() { + max := u32(484468466) + min := u32(316846) + for seed in seeds { + seed_data := [seed] + mut rng := sys.SysRNG{} + rng.seed(seed_data) + for _ in 0 .. range_limit { + value := rng.u32_in_range(min, max) + assert value >= min + assert value < max + } + } +} + +fn test_sys_rng_u64_in_range() { + max := u64(216468454685163) + min := u64(6848646868) + for seed in seeds { + seed_data := [seed] + mut rng := sys.SysRNG{} + rng.seed(seed_data) + for _ in 0 .. range_limit { + value := rng.u64_in_range(min, max) + assert value >= min + assert value < max + } + } +} + +fn test_sys_rng_intn() { + max := 2525642 + for seed in seeds { + seed_data := [seed] + mut rng := sys.SysRNG{} + rng.seed(seed_data) + for _ in 0 .. range_limit { + value := rng.intn(max) + assert value >= 0 + assert value < max + } + } +} + +fn test_sys_rng_i64n() { + max := i64(3246727724653636) + for seed in seeds { + seed_data := [seed] + mut rng := sys.SysRNG{} + rng.seed(seed_data) + for _ in 0 .. range_limit { + value := rng.i64n(max) + assert value >= 0 + assert value < max + } + } +} + +fn test_sys_rng_int_in_range() { + min := -4252 + max := 23054962 + for seed in seeds { + seed_data := [seed] + mut rng := sys.SysRNG{} + rng.seed(seed_data) + for _ in 0 .. range_limit { + value := rng.int_in_range(min, max) + assert value >= min + assert value < max + } + } +} + +fn test_sys_rng_i64_in_range() { + min := i64(-24095) + max := i64(324058) + for seed in seeds { + seed_data := [seed] + mut rng := sys.SysRNG{} + rng.seed(seed_data) + for _ in 0 .. range_limit { + value := rng.i64_in_range(min, max) + assert value >= min + assert value < max + } + } +} + +fn test_sys_rng_int31() { + max_u31 := int(0x7FFFFFFF) + sign_mask := int(0x80000000) + for seed in seeds { + seed_data := [seed] + mut rng := sys.SysRNG{} + rng.seed(seed_data) + for _ in 0 .. range_limit { + value := rng.int31() + assert value >= 0 + assert value <= max_u31 + // This statement ensures that the sign bit is zero + assert (value & sign_mask) == 0 + } + } +} + +fn test_sys_rng_int63() { + max_u63 := i64(0x7FFFFFFFFFFFFFFF) + sign_mask := i64(0x8000000000000000) + for seed in seeds { + seed_data := [seed] + mut rng := sys.SysRNG{} + rng.seed(seed_data) + for _ in 0 .. range_limit { + value := rng.int63() + assert value >= 0 + assert value <= max_u63 + assert (value & sign_mask) == 0 + } + } +} + +fn test_sys_rng_f32() { + for seed in seeds { + seed_data := [seed] + mut rng := sys.SysRNG{} + rng.seed(seed_data) + for _ in 0 .. range_limit { + value := rng.f32() + assert value >= 0.0 + assert value < 1.0 + } + } +} + +fn test_sys_rng_f64() { + for seed in seeds { + seed_data := [seed] + mut rng := sys.SysRNG{} + rng.seed(seed_data) + for _ in 0 .. range_limit { + value := rng.f64() + assert value >= 0.0 + assert value < 1.0 + } + } +} + +fn test_sys_rng_f32n() { + max := f32(357.0) + for seed in seeds { + seed_data := [seed] + mut rng := sys.SysRNG{} + rng.seed(seed_data) + for _ in 0 .. range_limit { + value := rng.f32n(max) + assert value >= 0.0 + assert value < max + } + } +} + +fn test_sys_rng_f64n() { + max := 1.52e6 + for seed in seeds { + seed_data := [seed] + mut rng := sys.SysRNG{} + rng.seed(seed_data) + for _ in 0 .. range_limit { + value := rng.f64n(max) + assert value >= 0.0 + assert value < max + } + } +} + +fn test_sys_rng_f32_in_range() { + min := f32(-24.0) + max := f32(125.0) + for seed in seeds { + seed_data := [seed] + mut rng := sys.SysRNG{} + rng.seed(seed_data) + for _ in 0 .. range_limit { + value := rng.f32_in_range(min, max) + assert value >= min + assert value < max + } + } +} + +fn test_sys_rng_f64_in_range() { + min := -548.7 + max := 5015.2 + for seed in seeds { + seed_data := [seed] + mut rng := sys.SysRNG{} + rng.seed(seed_data) + for _ in 0 .. range_limit { + value := rng.f64_in_range(min, max) + assert value >= min + assert value < max + } + } +} |