1 files changed, 62 insertions, 13 deletions

diff --git a/linden/indra/llmath/lluuid.cpp b/linden/indra/llmath/lluuid.cpp
index 216dac9..3fb31a6 100644
--- a/linden/indra/llmath/lluuid.cpp
+++ b/linden/indra/llmath/lluuid.cpp
@@ -110,6 +110,40 @@ unsigned int decode( char const * fiveChars ) throw( bad_input_data )
 } 
 */
 
+#define LL_USE_JANKY_RANDOM_NUMBER_GENERATOR 0
+#if LL_USE_JANKY_RANDOM_NUMBER_GENERATOR
+/**
+ * @brief a global for
+ */
+static U64 sJankyRandomSeed(LLUUID::getRandomSeed());
+
+/**
+ * @brief generate a random U32.
+ */
+U32 janky_fast_random_bytes()
+{
+        sJankyRandomSeed = U64L(1664525) * sJankyRandomSeed + U64L(1013904223); 
+        return (U32)sJankyRandomSeed;
+}
+
+/**
+ * @brief generate a random U32 from [0, val)
+ */
+U32 janky_fast_random_byes_range(U32 val)
+{
+        sJankyRandomSeed = U64L(1664525) * sJankyRandomSeed + U64L(1013904223); 
+        return (U32)(sJankyRandomSeed) % val; 
+}
+
+/**
+ * @brief generate a random U32 from [0, val)
+ */
+U32 janky_fast_random_seeded_bytes(U32 seed, U32 val)
+{
+        seed = U64L(1664525) * (U64)(seed) + U64L(1013904223); 
+        return (U32)(seed) % val; 
+}
+#endif
 
 // Common to all UUID implementations
 void LLUUID::toString(char *out) const
@@ -395,8 +429,16 @@ static void get_random_bytes(void *buf, int nbytes)
         int i;
         char *cp = (char *) buf;
 
+        // *NOTE: If we are not using the janky generator ll_rand()
+        // generates at least 3 good bytes of data since it is 0 to
+        // RAND_MAX. This could be made more efficient by copying all the
+        // bytes.
         for (i=0; i < nbytes; i++)
-                *cp++ = gLindenLabRandomNumber.llrand() & 0xFF;
+#if LL_USE_JANKY_RANDOM_NUMBER_GENERATOR
+                *cp++ = janky_fast_random_bytes() & 0xFF;
+#else
+                *cp++ = ll_rand() & 0xFF;
+#endif
         return; 
 }
 
@@ -738,18 +780,18 @@ void LLUUID::getCurrentTime(uuid_time_t *timestamp)
 
 void LLUUID::generate()
 {
-   // Create a UUID.
-
-
-   uuid_time_t timestamp;
+        // Create a UUID.
+        uuid_time_t timestamp;
 
-   static unsigned char node_id[6];
-   static int has_init = 0;
+        static unsigned char node_id[6];
+        static int has_init = 0;
    
-   // Create a UUID.
-   static uuid_time_t time_last = {0,0};
-   static U16 clock_seq = 0;
-   static LLRand random_generator(0);  // dummy seed.  reset it below
+        // Create a UUID.
+        static uuid_time_t time_last = {0,0};
+        static U16 clock_seq = 0;
+#if LL_USE_JANKY_RANDOM_NUMBER_GENERATOR
+        static U32 seed = 0L; // dummy seed.  reset it below
+#endif
         if (!has_init) 
         {
                 if (getNodeID(node_id) <= 0) 
@@ -764,8 +806,15 @@ void LLUUID::generate()
                 }
 
                 getCurrentTime(&time_last);
-                random_generator.seed(time_last.low);
-                clock_seq = (U16) random_generator.llrand(65536);
+#if LL_USE_JANKY_RANDOM_NUMBER_GENERATOR
+                seed = time_last.low;
+#endif
+
+#if LL_USE_JANKY_RANDOM_NUMBER_GENERATOR
+                clock_seq = (U16)janky_fast_random_seeded_bytes(seed, 65536);
+#else
+                clock_seq = (U16)ll_rand(65536);
+#endif
                 has_init = 1;
         }