Merging branches/v0.5-peernet/libbitdht (Merging r4237 through r4353 into '.')

There are many significant improvements to the DHT here. 
See commit logs on v0.5-peernet branch for details.

This is not the final merge, but brings over the majority of expected v0.5-peernet/libbitdht changes 




git-svn-id: http://svn.code.sf.net/p/retroshare/code/trunk@4354 b45a01b8-16f6-495d-af2f-9b41ad6348cc

libbitdht/src/util/bdrandom.cc

@@ -0,0 +1,93 @@
+#include <stdlib.h>
+#include <string>
+#include <unistd.h>
+#include "util/bdrandom.h"
+
+uint32_t bdRandom::index = 0 ;
+std::vector<uint32_t> bdRandom::MT(bdRandom::N,0u) ;
+bdMutex bdRandom::rndMtx ;
+
+#if defined(_WIN32) || defined(__MINGW32__)
+static bool auto_seed = bdRandom::seed( (time(NULL) + ((uint32_t) pthread_self().p)*0x1293fe)^0x18e34a12 ) ;
+#else
+  #ifdef __APPLE__
+	static bool auto_seed = bdRandom::seed( (time(NULL) + pthread_mach_thread_np(pthread_self())*0x1293fe + (getpid()^0x113ef76b))^0x18e34a12 ) ;
+  #else
+    static bool auto_seed = bdRandom::seed( (time(NULL) + pthread_self()*0x1293fe + (getpid()^0x113ef76b))^0x18e34a12 ) ;
+  #endif
+#endif
+bool bdRandom::seed(uint32_t s) 
+{
+	bdStackMutex mtx(rndMtx) ;
+
+	MT.resize(N,0) ;	// because MT might not be already resized
+
+	uint32_t j ;
+	MT[0]= s & 0xffffffffUL;
+	for (j=1; j<N; j++) 
+		MT[j] = (1812433253UL * (MT[j-1] ^ (MT[j-1] >> 30)) + j) & 0xffffffffUL ;
+
+	return true ;
+}
+
+void bdRandom::locked_next_state() 
+{
+	for(uint32_t i=0;i<N;++i)
+	{
+		uint32_t y = ((MT[i]) & UMASK) | ((MT[(i+1)%(int)N]) & LMASK) ;
+
+		MT[i] = MT[(i + M) % (int)N] ^ (y >> 1) ;
+
+		if((y & 1) == 1) 
+			MT[i] = MT[i] ^ 0x9908b0df ;
+	}
+	index = 0 ;
+}
+
+uint32_t bdRandom::random_u32() 
+{
+	uint32_t y;
+
+	{
+		bdStackMutex mtx(rndMtx) ;
+
+		y = MT[index++] ;
+
+		if(index == N)
+			locked_next_state();
+	}
+
+	// Tempering
+	y ^= (y >> 11);
+	y ^= (y << 7 ) & 0x9d2c5680UL;
+	y ^= (y << 15) & 0xefc60000UL;
+	y ^= (y >> 18);
+
+	return y;
+}
+
+uint64_t bdRandom::random_u64() 
+{
+	return ((uint64_t)random_u32() << 32ul) + random_u32() ;
+}
+
+float bdRandom::random_f32() 
+{
+	return random_u32() / (float)(~(uint32_t)0) ;
+}
+
+double bdRandom::random_f64() 
+{
+	return random_u64() / (double)(~(uint64_t)0) ;
+}
+
+std::string bdRandom::random_alphaNumericString(uint32_t len)
+{
+	std::string s = "" ;
+
+	for(uint32_t i=0;i<len;++i)
+		s += (char)( (random_u32()%94) + 33) ;
+
+	return s ;
+}
+