NotAShelf
ef0a20c1f8
Signed-off-by: NotAShelf <raf@notashelf.dev> Change-Id: I1802469f3baff4576f61accfb5a197d86a6a6964
22 lines
542 B
C
22 lines
542 B
C
#include "rng.h"
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// Linear congruential generator (LCG) state
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static unsigned int g_seed = 1;
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// LCG parameters (from numerical recipes)
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#define LCG_A 1664525
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#define LCG_C 1013904223
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#define LCG_MOD 4294967294 // 2^32 - 2 (avoid 0)
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void rng_seed(unsigned int seed) {
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// Ensure seed is never 0
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g_seed = (seed == 0) ? 1 : seed;
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}
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int rng_int(int min, int max) {
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// Generate next value
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g_seed = (LCG_A * g_seed + LCG_C) % LCG_MOD;
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// Map to [min, max] range
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return min + (int)((unsigned long long)g_seed % (max - min + 1));
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}
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