diff options
Diffstat (limited to 'indra/llcommon/llrand.cpp')
-rw-r--r-- | indra/llcommon/llrand.cpp | 104 |
1 files changed, 39 insertions, 65 deletions
diff --git a/indra/llcommon/llrand.cpp b/indra/llcommon/llrand.cpp index 1b6963a9dd..33afc50cf7 100644 --- a/indra/llcommon/llrand.cpp +++ b/indra/llcommon/llrand.cpp @@ -58,46 +58,14 @@ * to restore uniform distribution. */ -// *NOTE: The system rand implementation is probably not correct. -#define LL_USE_SYSTEM_RAND 0 +static LLRandLagFib2281 gRandomGenerator(LLUUID::getRandomSeed()); -#if LL_USE_SYSTEM_RAND -#include <cstdlib> -#endif +// no default implementation, only specific F64 and F32 specializations +template <typename REAL> +inline REAL ll_internal_random(); -#if LL_USE_SYSTEM_RAND -class LLSeedRand -{ -public: - LLSeedRand() - { -#if LL_WINDOWS - srand(LLUUID::getRandomSeed()); -#else - srand48(LLUUID::getRandomSeed()); -#endif - } -}; -static LLSeedRand sRandomSeeder; -inline F64 ll_internal_random_double() -{ -#if LL_WINDOWS - return (F64)rand() / (F64)(RAND_MAX+1); -#else - return drand48(); -#endif -} -inline F32 ll_internal_random_float() -{ -#if LL_WINDOWS - return (F32)rand() / (F32)(RAND_MAX+1); -#else - return (F32)drand48(); -#endif -} -#else -static LLRandLagFib2281 gRandomGenerator(LLUUID::getRandomSeed()); -inline F64 ll_internal_random_double() +template <> +inline F64 ll_internal_random<F64>() { // *HACK: Through experimentation, we have found that dual core // CPUs (or at least multi-threaded processes) seem to @@ -108,15 +76,35 @@ inline F64 ll_internal_random_double() return rv; } +template <> +inline F32 ll_internal_random<F32>() +{ + return F32(ll_internal_random<F64>()); +} + +/*------------------------------ F64 aliases -------------------------------*/ +inline F64 ll_internal_random_double() +{ + return ll_internal_random<F64>(); +} + +F64 ll_drand() +{ + return ll_internal_random_double(); +} + +/*------------------------------ F32 aliases -------------------------------*/ inline F32 ll_internal_random_float() { - // The clamping rules are described above. - F32 rv = (F32)gRandomGenerator(); - if(!((rv >= 0.0f) && (rv < 1.0f))) return fmod(rv, 1.f); - return rv; + return ll_internal_random<F32>(); +} + +F32 ll_frand() +{ + return ll_internal_random_float(); } -#endif +/*-------------------------- clamped random range --------------------------*/ S32 ll_rand() { return ll_rand(RAND_MAX); @@ -130,42 +118,28 @@ S32 ll_rand(S32 val) return rv; } -F32 ll_frand() -{ - return ll_internal_random_float(); -} - -F32 ll_frand(F32 val) +template <typename REAL> +REAL ll_grand(REAL val) { // The clamping rules are described above. - F32 rv = ll_internal_random_float() * val; + REAL rv = ll_internal_random<REAL>() * val; if(val > 0) { - if(rv >= val) return 0.0f; + if(rv >= val) return REAL(); } else { - if(rv <= val) return 0.0f; + if(rv <= val) return REAL(); } return rv; } -F64 ll_drand() +F32 ll_frand(F32 val) { - return ll_internal_random_double(); + return ll_grand<F32>(val); } F64 ll_drand(F64 val) { - // The clamping rules are described above. - F64 rv = ll_internal_random_double() * val; - if(val > 0) - { - if(rv >= val) return 0.0; - } - else - { - if(rv <= val) return 0.0; - } - return rv; + return ll_grand<F64>(val); } |