1 files changed, 117 insertions, 0 deletions
diff --git a/Random.h b/Random.h
new file mode 100644
index 0000000..7e0df3f
--- /dev/null
+++ b/Random.h
@@ -0,0 +1,117 @@
+#pragma once
+
+#include "Types.h"
+
+//-----------------------------------------------------------------------------
+// Xorshift RNG based on code by George Marsaglia
+// http://en.wikipedia.org/wiki/Xorshift
+
+struct Rand
+{
+  uint32_t x;
+  uint32_t y;
+  uint32_t z;
+  uint32_t w;
+
+  Rand()
+  {
+    reseed(uint32_t(0));
+  }
+
+  Rand( uint32_t seed )
+  {
+    reseed(seed);
+  }
+
+  void reseed ( uint32_t seed )
+  {
+    x = 0x498b3bc5 ^ seed;
+    y = 0;
+    z = 0;
+    w = 0;
+
+    for(int i = 0; i < 10; i++) mix();
+  }
+
+  void reseed ( uint64_t seed )
+  {
+    x = 0x498b3bc5 ^ (uint32_t)(seed >>  0);
+    y = 0x5a05089a ^ (uint32_t)(seed >> 32);
+    z = 0;
+    w = 0;
+
+    for(int i = 0; i < 10; i++) mix();
+  }
+
+  //-----------------------------------------------------------------------------
+
+  void mix ( void )
+  {
+    uint32_t t = x ^ (x << 11);
+    x = y; y = z; z = w;
+    w = w ^ (w >> 19) ^ t ^ (t >> 8); 
+  }
+
+  uint32_t rand_u32 ( void )
+  {
+    mix();
+
+    return x;
+  }
+
+  uint64_t rand_u64 ( void ) 
+  {
+    mix();
+
+    uint64_t a = x;
+    uint64_t b = y;
+
+    return (a << 32) | b;
+  }
+
+  void rand_p ( void * blob, int bytes )
+  {
+    uint32_t * blocks = reinterpret_cast<uint32_t*>(blob);
+
+    while(bytes >= 4)
+    {
+      blocks[0] = rand_u32();
+      blocks++;
+      bytes -= 4;
+    }
+
+    uint8_t * tail = reinterpret_cast<uint8_t*>(blocks);
+
+    for(int i = 0; i < bytes; i++)
+    {
+      tail[i] = (uint8_t)rand_u32();
+    }
+  }
+};
+
+//-----------------------------------------------------------------------------
+
+extern Rand g_rand1;
+
+inline uint32_t rand_u32 ( void ) { return g_rand1.rand_u32(); }
+inline uint64_t rand_u64 ( void ) { return g_rand1.rand_u64(); }
+
+inline void rand_p ( void * blob, int bytes )
+{
+  uint32_t * blocks = (uint32_t*)blob;
+
+  while(bytes >= 4)
+  {
+    *blocks++ = rand_u32();
+    bytes -= 4;
+  }
+
+  uint8_t * tail = (uint8_t*)blocks;
+
+  for(int i = 0; i < bytes; i++)
+  {
+    tail[i] = (uint8_t)rand_u32();
+  }
+}
+
+//-----------------------------------------------------------------------------