Abdelrahman Said
98 lines
2.2 KiB
C
98 lines
2.2 KiB
C
// vim:fileencoding=utf-8:foldmethod=marker
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#include "splitmix64.h"
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#include "../../common/aliases/aliases.h"
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#include "../../common/assert/assert.h"
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#include "../../common/platform/platform.h"
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#include <stdlib.h>
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#include <time.h>
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wp_intern void seedOsGenerator(u64 seed);
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wp_intern u64 genRandomNumber(void);
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WpSplitmix64State wpPrngSplitmix64Init(void) {
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wp_persist b8 seeded = false;
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if (!seeded) {
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seeded = true;
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seedOsGenerator(0);
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}
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return (WpSplitmix64State){ .seed = genRandomNumber() };
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}
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WpSplitmix64State wpPrngSplitmix64InitWithSeed(u64 seed) {
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return (WpSplitmix64State){ .seed = seed };
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}
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u64 wpPrngSplitmix64(WpSplitmix64State *state) {
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state->seed += 0x9E3779B97f4A7C15;
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u64 result = state->seed;
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result = (result ^ (result >> 30)) * 0xBF58476D1CE4E5B9;
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result = (result ^ (result >> 27)) * 0x94D049BB133111EB;
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return result ^ (result >> 31);
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}
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u64 wpPrngSplitmix64InRange(WpSplitmix64State *state, u64 start, u64 end) {
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return wpPrngSplitmix64(state) % (end - start) + start;
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}
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u64 wpPrngSplitmix64Choice(WpSplitmix64State *state, u64 available_choices) {
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return wpPrngSplitmix64(state) % available_choices;
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}
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#if defined(WP_PLATFORM_C) && WP_PLATFORM_C_VERSION >= WP_PLATFORM_C11_VERSION
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#ifdef WP_PLATFORM_POSIX
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wp_intern void seedOsGenerator(u64 seed) {
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if (seed == 0) {
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struct timespec ts = {0};
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int result = clock_gettime(CLOCK_MONOTONIC_RAW, &ts);
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wpRuntimeAssert(result == 0, "Invalid seed value");
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seed = (u64)ts.tv_nsec;
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}
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srand48(seed);
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}
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wp_intern u64 genRandomNumber(void) {
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return lrand48();
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}
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#else
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wp_intern void seedOsGenerator(u64 seed) {
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if (seed == 0) {
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struct timespec ts = {0};
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int result = timespec_get(&ts, TIME_UTC);
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wpRuntimeAssert(result != 0, "Invalid seed value");
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seed = (u64)ts.tv_nsec;
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}
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srand(seed);
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}
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wp_intern u64 genRandomNumber(void) {
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i32 n1 = rand();
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i32 n2 = rand();
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return (((u64)n1) << 32 | (u64)n2);
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}
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#endif // !WP_PLATFORM_POSIX
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#else
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wp_intern void seedOsGenerator(u64 seed) {
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if (seed == 0) {
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time_t result = time(NULL);
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wpRuntimeAssert(result != (time_t)(-1), "Invalid seed value");
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seed = (u64)result;
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}
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srand(seed);
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}
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wp_intern u64 genRandomNumber(void) {
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i32 n1 = rand();
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i32 n2 = rand();
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return (((u64)n1) << 32 | (u64)n2);
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}
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#endif // !WP_PLATFORM_C
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