Extract splitmix64 PRNG

CHANGELOG.md

@@ -17,6 +17,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Add `wpU8Const`, `wpU16Const`, `wpU32Const`, `wpU64Const`, `wpI8Const`, `wpI16Const`, `wpI32Const`, and `wpI64Const`
 - `wpPrngXorshiftInitWithSeed` to allow for user control with PRNG
 - `wpPrngXorshift256InRange`, `wpPrngXorshift256ssInRange`, `wpPrngXorshift256pInRange`, `wpPrngXorshift256Choice`, `wpPrngXorshift256ssChoice` and `wpPrngXorshift256pChoice` utilities
+- `WpSplitmix64State`
+- `wpPrngSplitmix64Init`, `wpPrngSplitmix64InitWithSeed`, `wpPrngSplitmix64`, `wpPrngSplitmix64InRange`, `wpPrngSplitmix64Choice`
 - `wpStr8Clear`
 
 ### Changed

src/prng/splitmix64/splitmix64.c

@@ -0,0 +1,97 @@
+// vim:fileencoding=utf-8:foldmethod=marker
+
+#include "splitmix64.h"
+#include "../../common/aliases/aliases.h"
+#include "../../common/assert/assert.h"
+#include "../../common/platform/platform.h"
+#include <stdlib.h>
+#include <time.h>
+
+wp_intern void seedOsGenerator(u64 seed);
+wp_intern u64 genRandomNumber(void);
+
+WpSplitmix64State wpPrngSplitmix64Init(void) {
+	wp_persist b8 seeded = false;
+	if (!seeded) {
+		seeded = true;
+		seedOsGenerator(0);
+	}
+
+	return (WpSplitmix64State){ .seed = genRandomNumber() };
+}
+
+WpSplitmix64State wpPrngSplitmix64InitWithSeed(u64 seed) {
+	return (WpSplitmix64State){ .seed = seed };
+}
+
+u64 wpPrngSplitmix64(WpSplitmix64State *state) {
+	state->seed += 0x9E3779B97f4A7C15;
+
+	u64 result = state->seed;
+	result = (result ^ (result >> 30)) * 0xBF58476D1CE4E5B9;
+	result = (result ^ (result >> 27)) * 0x94D049BB133111EB;
+
+	return result ^ (result >> 31);
+}
+
+u64 wpPrngSplitmix64InRange(WpSplitmix64State *state, u64 start, u64 end) {
+	return wpPrngSplitmix64(state) % (end - start) + start;
+}
+
+u64 wpPrngSplitmix64Choice(WpSplitmix64State *state, u64 available_choices) {
+	return wpPrngSplitmix64(state) % available_choices;
+}
+
+#if defined(WP_PLATFORM_C) && WP_PLATFORM_C_VERSION >= WP_PLATFORM_C11_VERSION
+#ifdef WP_PLATFORM_POSIX
+wp_intern void seedOsGenerator(u64 seed) {
+	if (seed == 0) {
+		struct timespec ts = {0};
+		int result = clock_gettime(CLOCK_MONOTONIC_RAW, &ts);
+		wpRuntimeAssert(result == 0, "Invalid seed value");
+		seed = (u64)ts.tv_nsec;
+	}
+
+	srand48(seed);
+}
+
+wp_intern u64 genRandomNumber(void) {
+	return lrand48();
+}
+#else
+wp_intern void seedOsGenerator(u64 seed) {
+	if (seed == 0) {
+		struct timespec ts = {0};
+		int result = timespec_get(&ts, TIME_UTC);
+		wpRuntimeAssert(result != 0, "Invalid seed value");
+		seed = (u64)ts.tv_nsec;
+	}
+
+	srand(seed);
+}
+
+wp_intern u64 genRandomNumber(void) {
+	i32 n1 = rand();
+	i32 n2 = rand();
+
+	return (((u64)n1) << 32 | (u64)n2);
+}
+#endif // !WP_PLATFORM_POSIX
+#else
+wp_intern void seedOsGenerator(u64 seed) {
+	if (seed == 0) {
+		time_t result = time(NULL);
+		wpRuntimeAssert(result != (time_t)(-1), "Invalid seed value");
+		seed = (u64)result;
+	}
+
+	srand(seed);
+}
+
+wp_intern u64 genRandomNumber(void) {
+	i32 n1 = rand();
+	i32 n2 = rand();
+
+	return (((u64)n1) << 32 | (u64)n2);
+}
+#endif // !WP_PLATFORM_C

src/prng/splitmix64/splitmix64.h

@@ -0,0 +1,18 @@
+// vim:fileencoding=utf-8:foldmethod=marker
+
+#ifndef SPLITMIX64_H
+#define SPLITMIX64_H
+
+#include "../../common/aliases/aliases.h"
+
+typedef struct WpSplitmix64State {
+	u64 seed;
+} WpSplitmix64State;
+
+WpSplitmix64State wpPrngSplitmix64Init(void);
+WpSplitmix64State wpPrngSplitmix64InitWithSeed(u64 seed);
+u64               wpPrngSplitmix64(WpSplitmix64State *state);
+u64               wpPrngSplitmix64InRange(WpSplitmix64State *state, u64 start, u64 end);
+u64               wpPrngSplitmix64Choice(WpSplitmix64State *state, u64 available_choices);
+
+#endif // !SPLITMIX64_H

src/prng/wapp_prng.c

@@ -3,6 +3,7 @@
 #ifndef WAPP_PRNG_C
 #define WAPP_PRNG_C
 
+#include "splitmix64/splitmix64.c"
 #include "xorshift/xorshift.c"
 
 #endif // !WAPP_PRNG_C

src/prng/wapp_prng.h

@@ -3,6 +3,7 @@
 #ifndef WAPP_PRNG_H
 #define WAPP_PRNG_H
 
+#include "splitmix64/splitmix64.h"
 #include "xorshift/xorshift.h"
 #include "../common/wapp_common.h"
 

src/prng/xorshift/xorshift.c

@@ -1,40 +1,29 @@
 // vim:fileencoding=utf-8:foldmethod=marker
 
 #include "xorshift.h"
+#include "../splitmix64/splitmix64.h"
 #include "../../common/aliases/aliases.h"
-#include "../../common/assert/assert.h"
-#include "../../common/platform/platform.h"
 #include "../../common/misc/misc_utils.h"
 #include <stdlib.h>
 #include <time.h>
 
-typedef struct SplitMix64State SplitMix64State;
-struct SplitMix64State {
-	u64 seed;
-};
-
-wp_intern u64 splitMix64(SplitMix64State *state);
-wp_intern void seedOsGenerator(u64 seed);
-wp_intern u64 genRandomNumber(void);
-
 WpXor256State wpPrngXorshiftInit(void) {
 	return wpPrngXorshiftInitWithSeed(0);
 }
 
 WpXor256State wpPrngXorshiftInitWithSeed(u64 seed) {
-	wp_persist b8 seeded = false;
-	if (!seeded) {
-		seeded = true;
-		seedOsGenerator(seed);
+	WpSplitmix64State sm64;
+	if (seed > 0) {
+		sm64 = wpPrngSplitmix64InitWithSeed(seed);
+	} else {
+		sm64 = wpPrngSplitmix64Init();
 	}
 
-	SplitMix64State sm64 = {.seed = genRandomNumber()};
-
 	return (WpXor256State){
-		.x = splitMix64(&sm64),
-		.y = splitMix64(&sm64),
-		.z = splitMix64(&sm64),
-		.w = splitMix64(&sm64),
+		.x = wpPrngSplitmix64(&sm64),
+		.y = wpPrngSplitmix64(&sm64),
+		.z = wpPrngSplitmix64(&sm64),
+		.w = wpPrngSplitmix64(&sm64),
 	};
 }
 
@@ -102,67 +91,3 @@ u64 wpPrngXorshift256ssChoice(WpXor256State *state, u64 available_choices) {
 u64 wpPrngXorshift256pChoice(WpXor256State *state, u64 available_choices) {
 	return wpPrngXorshift256p(state) % available_choices;
 }
-
-wp_intern u64 splitMix64(SplitMix64State *state) {
-	state->seed += 0x9E3779B97f4A7C15;
-
-	u64 result = state->seed;
-	result = (result ^ (result >> 30)) * 0xBF58476D1CE4E5B9;
-	result = (result ^ (result >> 27)) * 0x94D049BB133111EB;
-
-	return result ^ (result >> 31);
-}
-
-#if defined(WP_PLATFORM_C) && WP_PLATFORM_C_VERSION >= WP_PLATFORM_C11_VERSION
-#ifdef WP_PLATFORM_POSIX
-wp_intern void seedOsGenerator(u64 seed) {
-	if (seed == 0) {
-		struct timespec ts = {0};
-		int result = clock_gettime(CLOCK_MONOTONIC_RAW, &ts);
-		wpRuntimeAssert(result == 0, "Invalid seed value");
-		seed = (u64)ts.tv_nsec;
-	}
-
-	srand48(seed);
-}
-
-wp_intern u64 genRandomNumber(void) {
-	return lrand48();
-}
-#else
-wp_intern void seedOsGenerator(u64 seed) {
-	if (seed == 0) {
-		struct timespec ts = {0};
-		int result = timespec_get(&ts, TIME_UTC);
-		wpRuntimeAssert(result != 0, "Invalid seed value");
-		seed = (u64)ts.tv_nsec;
-	}
-
-	srand(seed);
-}
-
-wp_intern u64 genRandomNumber(void) {
-	i32 n1 = rand();
-	i32 n2 = rand();
-
-	return (((u64)n1) << 32 | (u64)n2);
-}
-#endif // !WP_PLATFORM_POSIX
-#else
-wp_intern void seedOsGenerator(u64 seed) {
-	if (seed == 0) {
-		time_t result = time(NULL);
-		wpRuntimeAssert(result != (time_t)(-1), "Invalid seed value");
-		seed = (u64)result;
-	}
-
-	srand(seed);
-}
-
-wp_intern u64 genRandomNumber(void) {
-	i32 n1 = rand();
-	i32 n2 = rand();
-
-	return (((u64)n1) << 32 | (u64)n2);
-}
-#endif // !WP_PLATFORM_C