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authorIndrajith K L2022-12-03 17:00:20 +0530
committerIndrajith K L2022-12-03 17:00:20 +0530
commitf5c4671bfbad96bf346bd7e9a21fc4317b4959df (patch)
tree2764fc62da58f2ba8da7ed341643fc359873142f /v_windows/v/vlib/rand/wyrand/wyrand.v
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Adds most of the toolsHEADmaster
Diffstat (limited to 'v_windows/v/vlib/rand/wyrand/wyrand.v')
-rw-r--r--v_windows/v/vlib/rand/wyrand/wyrand.v252
1 files changed, 252 insertions, 0 deletions
diff --git a/v_windows/v/vlib/rand/wyrand/wyrand.v b/v_windows/v/vlib/rand/wyrand/wyrand.v
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+++ b/v_windows/v/vlib/rand/wyrand/wyrand.v
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+// 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 wyrand
+
+import math.bits
+import rand.seed
+import rand.constants
+import hash
+
+// Redefinition of some constants that we will need for pseudorandom number generation.
+const (
+ wyp0 = u64(0xa0761d6478bd642f)
+ wyp1 = u64(0xe7037ed1a0b428db)
+)
+
+// WyRandRNG is a RNG based on the WyHash hashing algorithm.
+pub struct WyRandRNG {
+mut:
+ state u64 = seed.time_seed_64()
+ has_extra bool
+ extra u32
+}
+
+// seed sets the seed, needs only two `u32`s in little-endian format as [lower, higher].
+pub fn (mut rng WyRandRNG) seed(seed_data []u32) {
+ if seed_data.len != 2 {
+ eprintln('WyRandRNG needs 2 32-bit unsigned integers as the seed.')
+ exit(1)
+ }
+ rng.state = seed_data[0] | (u64(seed_data[1]) << 32)
+ rng.has_extra = false
+}
+
+// u32 updates the PRNG state and returns the next pseudorandom `u32`.
+[inline]
+pub fn (mut rng WyRandRNG) u32() u32 {
+ if rng.has_extra {
+ rng.has_extra = false
+ return rng.extra
+ }
+ full_value := rng.u64()
+ lower := u32(full_value & constants.lower_mask)
+ upper := u32(full_value >> 32)
+ rng.extra = upper
+ rng.has_extra = true
+ return lower
+}
+
+// u64 updates the PRNG state and returns the next pseudorandom `u64`.
+[inline]
+pub fn (mut rng WyRandRNG) u64() u64 {
+ unsafe {
+ mut seed1 := rng.state
+ seed1 += wyrand.wyp0
+ rng.state = seed1
+ return hash.wymum(seed1 ^ wyrand.wyp1, seed1)
+ }
+ return 0
+}
+
+// u32n returns a pseudorandom `u32` less than `max`.
+[inline]
+pub fn (mut rng WyRandRNG) u32n(max u32) u32 {
+ if max == 0 {
+ eprintln('max must be positive integer')
+ exit(1)
+ }
+ // Check SysRNG in system_rng.c.v for explanation
+ bit_len := bits.len_32(max)
+ if bit_len == 32 {
+ for {
+ value := rng.u32()
+ if value < max {
+ return value
+ }
+ }
+ } else {
+ mask := (u32(1) << (bit_len + 1)) - 1
+ for {
+ value := rng.u32() & mask
+ if value < max {
+ return value
+ }
+ }
+ }
+ return u32(0)
+}
+
+// u64n returns a pseudorandom `u64` less than `max`.
+[inline]
+pub fn (mut rng WyRandRNG) u64n(max u64) u64 {
+ if max == 0 {
+ eprintln('max must be positive integer')
+ exit(1)
+ }
+ bit_len := bits.len_64(max)
+ if bit_len == 64 {
+ for {
+ value := rng.u64()
+ if value < max {
+ return value
+ }
+ }
+ } else {
+ mask := (u64(1) << (bit_len + 1)) - 1
+ for {
+ value := rng.u64() & mask
+ if value < max {
+ return value
+ }
+ }
+ }
+ return u64(0)
+}
+
+// u32n returns a pseudorandom `u32` value that is guaranteed to be in range `[min, max)`.
+[inline]
+pub fn (mut rng WyRandRNG) u32_in_range(min u32, max u32) u32 {
+ if max <= min {
+ eprintln('max must be greater than min')
+ exit(1)
+ }
+ return min + rng.u32n(max - min)
+}
+
+// u64n returns a pseudorandom `u64` value that is guaranteed to be in range `[min, max)`.
+[inline]
+pub fn (mut rng WyRandRNG) u64_in_range(min u64, max u64) u64 {
+ if max <= min {
+ eprintln('max must be greater than min')
+ exit(1)
+ }
+ return min + rng.u64n(max - min)
+}
+
+// int returns a (possibly negative) pseudorandom 32-bit `int`.
+[inline]
+pub fn (mut rng WyRandRNG) int() int {
+ return int(rng.u32())
+}
+
+// i64 returns a (possibly negative) pseudorandom 64-bit `i64`.
+[inline]
+pub fn (mut rng WyRandRNG) i64() i64 {
+ return i64(rng.u64())
+}
+
+// int31 returns a positive pseudorandom 31-bit `int`.
+[inline]
+pub fn (mut rng WyRandRNG) int31() int {
+ return int(rng.u32() & constants.u31_mask) // Set the 32nd bit to 0.
+}
+
+// int63 returns a positive pseudorandom 63-bit `i64`.
+[inline]
+pub fn (mut rng WyRandRNG) int63() i64 {
+ return i64(rng.u64() & constants.u63_mask) // Set the 64th bit to 0.
+}
+
+// intn returns a pseudorandom `int` in range `[0, max)`.
+[inline]
+pub fn (mut rng WyRandRNG) intn(max int) int {
+ if max <= 0 {
+ eprintln('max has to be positive.')
+ exit(1)
+ }
+ return int(rng.u32n(u32(max)))
+}
+
+// i64n returns a pseudorandom int that lies in `[0, max)`.
+[inline]
+pub fn (mut rng WyRandRNG) i64n(max i64) i64 {
+ if max <= 0 {
+ eprintln('max has to be positive.')
+ exit(1)
+ }
+ return i64(rng.u64n(u64(max)))
+}
+
+// int_in_range returns a pseudorandom `int` in range `[min, max)`.
+[inline]
+pub fn (mut rng WyRandRNG) 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 + rng.intn(max - min)
+}
+
+// i64_in_range returns a pseudorandom `i64` in range `[min, max)`.
+[inline]
+pub fn (mut rng WyRandRNG) i64_in_range(min i64, max i64) i64 {
+ if max <= min {
+ eprintln('max must be greater than min')
+ exit(1)
+ }
+ return min + rng.i64n(max - min)
+}
+
+// f32 returns a pseudorandom `f32` value in range `[0, 1)`.
+[inline]
+pub fn (mut rng WyRandRNG) f32() f32 {
+ return f32(rng.u32()) / constants.max_u32_as_f32
+}
+
+// f64 returns a pseudorandom `f64` value in range `[0, 1)`.
+[inline]
+pub fn (mut rng WyRandRNG) f64() f64 {
+ return f64(rng.u64()) / constants.max_u64_as_f64
+}
+
+// f32n returns a pseudorandom `f32` value in range `[0, max)`.
+[inline]
+pub fn (mut rng WyRandRNG) f32n(max f32) f32 {
+ if max <= 0 {
+ eprintln('max has to be positive.')
+ exit(1)
+ }
+ return rng.f32() * max
+}
+
+// f64n returns a pseudorandom `f64` value in range `[0, max)`.
+[inline]
+pub fn (mut rng WyRandRNG) f64n(max f64) f64 {
+ if max <= 0 {
+ eprintln('max has to be positive.')
+ exit(1)
+ }
+ return rng.f64() * max
+}
+
+// f32_in_range returns a pseudorandom `f32` in range `[min, max)`.
+[inline]
+pub fn (mut rng WyRandRNG) f32_in_range(min f32, max f32) f32 {
+ if max <= min {
+ eprintln('max must be greater than min')
+ exit(1)
+ }
+ return min + rng.f32n(max - min)
+}
+
+// i64_in_range returns a pseudorandom `i64` in range `[min, max)`.
+[inline]
+pub fn (mut rng WyRandRNG) f64_in_range(min f64, max f64) f64 {
+ if max <= min {
+ eprintln('max must be greater than min')
+ exit(1)
+ }
+ return min + rng.f64n(max - min)
+}