move rand functions from util to new random.h/.cpp

src/random.h

@@ -0,0 +1,49 @@
+// Copyright (c) 2009-2010 Satoshi Nakamoto
+// Copyright (c) 2009-2014 The Bitcoin developers
+// Distributed under the MIT/X11 software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#ifndef BITCOIN_RANDOM_H
+#define BITCOIN_RANDOM_H
+
+#include "uint256.h"
+
+#include <stdint.h>
+
+/**
+ * Seed OpenSSL PRNG with additional entropy data
+ */
+void RandAddSeed();
+void RandAddSeedPerfmon();
+
+/**
+ * Functions to gather random data via the OpenSSL PRNG
+ */
+bool GetRandBytes(unsigned char *buf, int num);
+uint64_t GetRand(uint64_t nMax);
+int GetRandInt(int nMax);
+uint256 GetRandHash();
+
+/**
+ * Seed insecure_rand using the random pool.
+ * @param Deterministic Use a determinstic seed
+ */
+void seed_insecure_rand(bool fDeterministic = false);
+
+/**
+ * MWC RNG of George Marsaglia
+ * This is intended to be fast. It has a period of 2^59.3, though the
+ * least significant 16 bits only have a period of about 2^30.1.
+ *
+ * @return random value
+ */
+extern uint32_t insecure_rand_Rz;
+extern uint32_t insecure_rand_Rw;
+static inline uint32_t insecure_rand(void)
+{
+    insecure_rand_Rz = 36969 * (insecure_rand_Rz & 65535) + (insecure_rand_Rz >> 16);
+    insecure_rand_Rw = 18000 * (insecure_rand_Rw & 65535) + (insecure_rand_Rw >> 16);
+    return (insecure_rand_Rw << 16) + insecure_rand_Rz;
+}
+
+#endif // BITCOIN_RANDOM_H