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Add Random::fillBitsRandomly

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This commit is contained in:
Vinnie Falco
2013-08-02 01:19:23 -07:00
parent 6d8a34540c
commit be3f19c811
2 changed files with 17 additions and 21 deletions
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31
Subtrees/beast/modules/beast_core/maths/beast_Random.cpp
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@@ -103,23 +103,6 @@ double Random::nextDouble() noexcept
return static_cast <uint32> (nextInt()) / (double) 0xffffffff;
}
void Random::nextBlob (void* buffer, size_t bytes)
{
int const remainder = bytes % sizeof (int64);
{
int64* dest = static_cast <int64*> (buffer);
for (int i = bytes / sizeof (int64); i > 0; --i)
*dest++ = nextInt64 ();
buffer = dest;
}
{
int64 const val = nextInt64 ();
memcpy (buffer, &val, remainder);
}
}
BigInteger Random::nextLargeNumber (const BigInteger& maximumValue)
{
BigInteger n;
@@ -133,6 +116,20 @@ BigInteger Random::nextLargeNumber (const BigInteger& maximumValue)
return n;
}
void Random::fillBitsRandomly (void* const buffer, size_t bytes)
{
int* d = static_cast<int*> (buffer);
for (; bytes >= sizeof (int); bytes -= sizeof (int))
*d++ = nextInt();
if (bytes > 0)
{
const int lastBytes = nextInt();
memcpy (d, &lastBytes, bytes);
}
}
void Random::fillBitsRandomly (BigInteger& arrayToChange, int startBit, int numBits)
{
arrayToChange.setBit (startBit + numBits - 1, true); // to force the array to pre-allocate space

7
Subtrees/beast/modules/beast_core/maths/beast_Random.h
View File

@@ -89,16 +89,15 @@ public:
*/
bool nextBool() noexcept;
/** Fills a piece of memory with random data.
*/
void nextBlob (void* buffer, size_t bytes);
/** Returns a BigInteger containing a random number.
@returns a random value in the range 0 to (maximumValue - 1).
*/
BigInteger nextLargeNumber (const BigInteger& maximumValue);
/** Fills a block of memory with random values. */
void fillBitsRandomly (void* bufferToFill, size_t sizeInBytes);
/** Sets a range of bits in a BigInteger to random values. */
void fillBitsRandomly (BigInteger& arrayToChange, int startBit, int numBits);