51 lines
1.1 KiB
V
51 lines
1.1 KiB
V
// Copyright (c) 2019-2020 Alexander Medvednikov. All rights reserved.
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// Use of this source code is governed by an MIT license
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// that can be found in the LICENSE file.
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module rand
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const (
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max_i32 = 2147483647
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)
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fn C.rand() int
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pub fn seed(s int) {
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C.srand(s)
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}
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pub fn next(max int) int {
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return C.rand() % max
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}
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// rand_r returns a pseudo-random number;
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// writes a result value to the seed argument.
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pub fn rand_r(seed &int) int {
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ns := *seed * 1103515245 + 12345
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unsafe {
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(*seed) = ns
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}
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return ns & 0x7fffffff
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}
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// rand_f32 return a random f32 between 0 and max
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pub fn rand_f32(max f32) f32 {
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return f32(f64(C.rand()) / f64(C.RAND_MAX) * f64(max))
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}
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// rand_f32 return a random f32 in range min and max
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pub fn rand_f32_in_range(min, max f32) f32 {
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scaled_r := f32(next(max_i32)) / max_i32
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return min + scaled_r * (max - min)
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}
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// rand_f64 return a random f64 between 0 and max
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pub fn rand_f64(max f32) f32 {
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return f64(C.rand()) / f64(C.RAND_MAX) * f64(max)
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}
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// rand_f64 return a random f64 in range min and max
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pub fn rand_f64_in_range(min, max f64) f64 {
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scaled_r := f64(next(max_i32)) / max_i32
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return min + scaled_r * (max - min)
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}
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