Reorganization

code/hash.c

@@ -0,0 +1,53 @@
+#include "hash.h"
+
+// FNV HASH (1a?)
+HASH_API_FUNCTION uint64_t HashBytes(void *data, uint64_t size) {
+    uint8_t *data8 = (uint8_t *)data;
+    uint64_t hash = (uint64_t)14695981039346656037ULL;
+    for (uint64_t i = 0; i < size; i++) {
+        hash = hash ^ (uint64_t)(data8[i]);
+        hash = hash * (uint64_t)1099511628211ULL;
+    }
+    return hash;
+}
+
+HASH_API_FUNCTION RandomSeed MakeRandomSeed(uint64_t value) {
+    RandomSeed result;
+    result.a = value;
+    return result;
+}
+
+HASH_API_FUNCTION uint64_t GetRandomU64(RandomSeed *state) {
+    uint64_t x = state->a;
+    x ^= x << 13;
+    x ^= x >> 7;
+    x ^= x << 17;
+    return state->a = x;
+}
+
+HASH_API_FUNCTION int GetRandomRangeI(RandomSeed *seed, int first, int last_included) {
+    uint64_t random = GetRandomU64(seed);
+    int range = (last_included - first + 1);
+    int mapped = random % range;
+    int result = mapped + first;
+    return result;
+}
+
+HASH_API_FUNCTION double GetRandomNormal(RandomSeed *series) {
+    uint64_t rnd = GetRandomU64(series);
+    double result = (double)rnd / (double)UINT64_MAX;
+    return result;
+}
+
+HASH_API_FUNCTION double GetRandomNormalRange(RandomSeed *seed, double min, double max) {
+    double value = GetRandomNormal(seed);
+    double result = value * (max - min) + min;
+    return result;
+}
+
+HASH_API_FUNCTION uint64_t HashMix(uint64_t x, uint64_t y) {
+    x ^= y;
+    x *= 0xff51afd7ed558ccd;
+    x ^= x >> 32;
+    return x;
+}