moved the BitArray::fillBitsRandomly() and BitArray::createRandomNumber() methods across to the Random class.

juce_amalgamated.cpp

@@ -804,7 +804,7 @@ void Random::setSeedRandomly()
     Random r3 (Time::getHighResolutionTicksPerSecond());
     Random r4 (Time::currentTimeMillis());
 
-    setSeed (r1.nextInt64() ^ r2.nextInt64()
+    setSeed (nextInt64() ^ r1.nextInt64() ^ r2.nextInt64()
                ^ r3.nextInt64() ^ r4.nextInt64());
 }
 
@@ -841,10 +841,43 @@ double Random::nextDouble() throw()
     return ((uint32) nextInt()) / (double) 0xffffffff;
 }
 
-static Random sysRand (1);
+const BitArray Random::nextLargeNumber (const BitArray& maximumValue) throw()
+{
+    BitArray n;
+
+    do
+    {
+        fillBitsRandomly (n, 0, maximumValue.getHighestBit() + 1);
+    }
+    while (n.compare (maximumValue) >= 0);
+
+    return n;
+}
+
+void Random::fillBitsRandomly (BitArray& arrayToChange, int startBit, int numBits) throw()
+{
+    arrayToChange.setBit (startBit + numBits - 1, true);  // to force the array to pre-allocate space
+
+    while ((startBit & 31) != 0 && numBits > 0)
+    {
+        arrayToChange.setBit (startBit++, nextBool());
+        --numBits;
+    }
+
+    while (numBits >= 32)
+    {
+        arrayToChange.setBitRangeAsInt (startBit, 32, (unsigned int) nextInt());
+        startBit += 32;
+        numBits -= 32;
+    }
+
+    while (--numBits >= 0)
+        arrayToChange.setBit (startBit + numBits, nextBool());
+}
 
 Random& Random::getSystemRandom() throw()
 {
+    static Random sysRand (1);
     return sysRand;
 }
 
@@ -1123,9 +1156,10 @@ void JUCE_PUBLIC_FUNCTION initialiseJuce_NonGUI()
         juceInitialisedNonGUI = true;
 
         DBG (SystemStats::getJUCEVersion());
+        Random::getSystemRandom().setSeedRandomly(); // (calling this more than once improves its randomness)
         juce_initialiseStrings();
         SystemStats::initialiseStats();
-        Random::getSystemRandom().setSeedRandomly();
+        Random::getSystemRandom().setSeedRandomly(); // (calling this more than once improves its randomness)
     }
 }
 
@@ -2395,45 +2429,6 @@ void BitArray::setBitRangeAsInt (const int startBit, int numBits, unsigned int v
     }
 }
 
-void BitArray::fillBitsRandomly (int startBit, int numBits) throw()
-{
-    highestBit = jmax (highestBit, startBit + numBits);
-    ensureSize (((startBit + numBits) >> 5) + 1);
-
-    while ((startBit & 31) != 0 && numBits > 0)
-    {
-        setBit (startBit++, Random::getSystemRandom().nextBool());
-
-        --numBits;
-    }
-
-    while (numBits >= 32)
-    {
-        values [startBit >> 5] = (unsigned int) Random::getSystemRandom().nextInt();
-
-        startBit += 32;
-        numBits -= 32;
-    }
-
-    while (--numBits >= 0)
-    {
-        setBit (startBit + numBits, Random::getSystemRandom().nextBool());
-    }
-
-    highestBit = getHighestBit();
-}
-
-void BitArray::createRandomNumber (const BitArray& maximumValue) throw()
-{
-    clear();
-
-    do
-    {
-        fillBitsRandomly (0, maximumValue.getHighestBit() + 1);
-    }
-    while (compare (maximumValue) >= 0);
-}
-
 bool BitArray::isNegative() const throw()
 {
     return negative && ! isEmpty();
@@ -4076,16 +4071,16 @@ const BitArray Primes::createProbablePrime (const int bitLength,
                                             const int* randomSeeds,
                                             int numRandomSeeds) throw()
 {
-    int defaultSeeds[8];
+    int defaultSeeds [16];
 
     if (numRandomSeeds <= 0)
     {
         randomSeeds = defaultSeeds;
-        numRandomSeeds = 8;
+        numRandomSeeds = numElementsInArray (defaultSeeds);
+        Random r (0);
 
         for (int j = 10; --j >= 0;)
         {
-            Random r (0);
             r.setSeedRandomly();
 
             for (int i = numRandomSeeds; --i >= 0;)
@@ -4101,15 +4096,14 @@ const BitArray Primes::createProbablePrime (const int bitLength,
 
     for (int i = numRandomSeeds; --i >= 0;)
     {
-        Random::getSystemRandom().setSeed (randomSeeds[i]);
-
         BitArray p2;
-        p2.fillBitsRandomly (0, bitLength);
+
+        Random r (randomSeeds[i]);
+        r.fillBitsRandomly (p2, 0, bitLength);
+
         p.xorWith (p2);
     }
 
-    Random::getSystemRandom().setSeedRandomly();
-
     p.setBit (bitLength - 1);
     p.clearBit (0);
 

src/juce_core/basics/juce_Random.cpp

@@ -34,8 +34,8 @@
 BEGIN_JUCE_NAMESPACE
 
 #include "juce_Random.h"
-#include "../basics/juce_Time.h"
-#include "../basics/juce_SystemStats.h"
+#include "juce_Time.h"
+#include "juce_SystemStats.h"
 
 
 //==============================================================================
@@ -60,7 +60,7 @@ void Random::setSeedRandomly()
     Random r3 (Time::getHighResolutionTicksPerSecond());
     Random r4 (Time::currentTimeMillis());
 
-    setSeed (r1.nextInt64() ^ r2.nextInt64()
+    setSeed (nextInt64() ^ r1.nextInt64() ^ r2.nextInt64()
                ^ r3.nextInt64() ^ r4.nextInt64());
 }
 
@@ -98,11 +98,44 @@ double Random::nextDouble() throw()
     return ((uint32) nextInt()) / (double) 0xffffffff;
 }
 
-//==============================================================================
-static Random sysRand (1);
+const BitArray Random::nextLargeNumber (const BitArray& maximumValue) throw()
+{
+    BitArray n;
+
+    do
+    {
+        fillBitsRandomly (n, 0, maximumValue.getHighestBit() + 1);
+    }
+    while (n.compare (maximumValue) >= 0);
+
+    return n;
+}
 
+void Random::fillBitsRandomly (BitArray& arrayToChange, int startBit, int numBits) throw()
+{
+    arrayToChange.setBit (startBit + numBits - 1, true);  // to force the array to pre-allocate space
+
+    while ((startBit & 31) != 0 && numBits > 0)
+    {
+        arrayToChange.setBit (startBit++, nextBool());
+        --numBits;
+    }
+
+    while (numBits >= 32)
+    {
+        arrayToChange.setBitRangeAsInt (startBit, 32, (unsigned int) nextInt());
+        startBit += 32;
+        numBits -= 32;
+    }
+
+    while (--numBits >= 0)
+        arrayToChange.setBit (startBit + numBits, nextBool());
+}
+
+//==============================================================================
 Random& Random::getSystemRandom() throw()
 {
+    static Random sysRand (1);
     return sysRand;
 }
 

src/juce_core/basics/juce_Random.h

@@ -32,6 +32,8 @@
 #ifndef __JUCE_RANDOM_JUCEHEADER__
 #define __JUCE_RANDOM_JUCEHEADER__
 
+#include "../containers/juce_BitArray.h"
+
 
 //==============================================================================
 /**
@@ -88,6 +90,15 @@ public:
     */
     bool nextBool() throw();
 
+    /** Returns a BitArray containing a random number.
+
+        @returns a random value in the range 0 to (maximumValue - 1).
+    */
+    const BitArray nextLargeNumber (const BitArray& maximumValue) throw();
+
+    /** Sets a range of bits in a BitArray to random values. */
+    void fillBitsRandomly (BitArray& arrayToChange, int startBit, int numBits) throw();
+
     //==============================================================================
     /** To avoid the overhead of having to create a new Random object whenever
         you need a number, this is a shared application-wide object that
@@ -100,8 +111,11 @@ public:
     /** Resets this Random object to a given seed value. */
     void setSeed (const int64 newSeed) throw();
 
-    /** Reseeds this generator using a value generated from various semi-random system 
+    /** Reseeds this generator using a value generated from various semi-random system
         properties like the current time, etc.
+
+        Because this function convolves the time with the last seed value, calling
+        it repeatedly will increase the randomness of the final result.
     */
     void setSeedRandomly();
 

src/juce_core/basics/juce_SystemStats.cpp

@@ -84,9 +84,10 @@ void JUCE_PUBLIC_FUNCTION initialiseJuce_NonGUI()
         juceInitialisedNonGUI = true;
 
         DBG (SystemStats::getJUCEVersion());
+        Random::getSystemRandom().setSeedRandomly(); // (calling this more than once improves its randomness)
         juce_initialiseStrings();
         SystemStats::initialiseStats();
-        Random::getSystemRandom().setSeedRandomly();
+        Random::getSystemRandom().setSeedRandomly(); // (calling this more than once improves its randomness)
     }
 }
 

src/juce_core/containers/juce_BitArray.cpp

@@ -736,46 +736,6 @@ void BitArray::setBitRangeAsInt (const int startBit, int numBits, unsigned int v
     }
 }
 
-//==============================================================================
-void BitArray::fillBitsRandomly (int startBit, int numBits) throw()
-{
-    highestBit = jmax (highestBit, startBit + numBits);
-    ensureSize (((startBit + numBits) >> 5) + 1);
-
-    while ((startBit & 31) != 0 && numBits > 0)
-    {
-        setBit (startBit++, Random::getSystemRandom().nextBool());
-
-        --numBits;
-    }
-
-    while (numBits >= 32)
-    {
-        values [startBit >> 5] = (unsigned int) Random::getSystemRandom().nextInt();
-
-        startBit += 32;
-        numBits -= 32;
-    }
-
-    while (--numBits >= 0)
-    {
-        setBit (startBit + numBits, Random::getSystemRandom().nextBool());
-    }
-
-    highestBit = getHighestBit();
-}
-
-void BitArray::createRandomNumber (const BitArray& maximumValue) throw()
-{
-    clear();
-
-    do
-    {
-        fillBitsRandomly (0, maximumValue.getHighestBit() + 1);
-    }
-    while (compare (maximumValue) >= 0);
-}
-
 //==============================================================================
 bool BitArray::isNegative() const throw()
 {

src/juce_core/containers/juce_BitArray.h

@@ -289,13 +289,6 @@ public:
     */
     int getHighestBit() const throw();
 
-    //==============================================================================
-    /** Sets a range of bits to random values. */
-    void fillBitsRandomly (int startBit, int numBits) throw();
-
-    /** Turns this value into a random number less than the given value. */
-    void createRandomNumber (const BitArray& maximumValue) throw();
-
     //==============================================================================
     /** Converts the array to a number string.
 

src/juce_core/cryptography/juce_Primes.cpp

@@ -126,16 +126,16 @@ const BitArray Primes::createProbablePrime (const int bitLength,
                                             const int* randomSeeds,
                                             int numRandomSeeds) throw()
 {
-    int defaultSeeds[8];
+    int defaultSeeds [16];
 
     if (numRandomSeeds <= 0)
     {
         randomSeeds = defaultSeeds;
-        numRandomSeeds = 8;
+        numRandomSeeds = numElementsInArray (defaultSeeds);
+        Random r (0);
 
         for (int j = 10; --j >= 0;)
         {
-            Random r (0);
             r.setSeedRandomly();
 
             for (int i = numRandomSeeds; --i >= 0;)
@@ -151,15 +151,14 @@ const BitArray Primes::createProbablePrime (const int bitLength,
 
     for (int i = numRandomSeeds; --i >= 0;)
     {
-        Random::getSystemRandom().setSeed (randomSeeds[i]);
-
         BitArray p2;
-        p2.fillBitsRandomly (0, bitLength);
+
+        Random r (randomSeeds[i]);
+        r.fillBitsRandomly (p2, 0, bitLength);
+
         p.xorWith (p2);
     }
 
-    Random::getSystemRandom().setSeedRandomly();
-
     p.setBit (bitLength - 1);
     p.clearBit (0);