diff options
| -rw-r--r-- | indra/llcommon/llrand.cpp | 96 |
1 files changed, 55 insertions, 41 deletions
diff --git a/indra/llcommon/llrand.cpp b/indra/llcommon/llrand.cpp index cb28a8f5c3..4e4345f37a 100644 --- a/indra/llcommon/llrand.cpp +++ b/indra/llcommon/llrand.cpp @@ -58,14 +58,18 @@ * to restore uniform distribution. */ +template <typename REAL> +inline REAL ll_internal_random(); + // *NOTE: The system rand implementation is probably not correct. #define LL_USE_SYSTEM_RAND 0 +/***************************************************************************** +* The LL_USE_SYSTEM_RAND implementation has been disabled since June 2008. +*****************************************************************************/ #if LL_USE_SYSTEM_RAND #include <cstdlib> -#endif -#if LL_USE_SYSTEM_RAND class LLSeedRand { public: @@ -79,25 +83,25 @@ public: } }; static LLSeedRand sRandomSeeder; -inline F64 ll_internal_random_double() + +template <> +inline F64 ll_internal_random<F64>() { #if LL_WINDOWS - return (F64)rand() / (F64)RAND_MAX; + 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; -#else - return (F32)drand48(); -#endif -} -#else + +/***************************************************************************** +* This is the implementation we've been using. +*****************************************************************************/ +#else // LL_USE_SYSTEM_RAND 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 @@ -107,16 +111,40 @@ inline F64 ll_internal_random_double() if(!((rv >= 0.0) && (rv < 1.0))) return fmod(rv, 1.0); return rv; } +#endif // LL_USE_SYSTEM_RAND + +/***************************************************************************** +* Functions common to both implementations +*****************************************************************************/ +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>(); } -#endif +F32 ll_frand() +{ + return ll_internal_random_float(); +} + +/*-------------------------- clamped random range --------------------------*/ S32 ll_rand() { return ll_rand(RAND_MAX); @@ -130,42 +158,28 @@ 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); } |