//------------------------------------------------------------------------------
/*
	Copyright (c) 2011-2013, OpenCoin, Inc.

	Permission to use, copy, modify, and/or distribute this software for any
	purpose with  or without fee is hereby granted,  provided that the above
	copyright notice and this permission notice appear in all copies.

	THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
	WITH  REGARD  TO  THIS  SOFTWARE  INCLUDING  ALL  IMPLIED  WARRANTIES OF
	MERCHANTABILITY  AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
	ANY SPECIAL,  DIRECT, INDIRECT,  OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
	WHATSOEVER  RESULTING  FROM LOSS OF USE, DATA OR PROFITS,  WHETHER IN AN
	ACTION OF CONTRACT, NEGLIGENCE  OR OTHER TORTIOUS ACTION, ARISING OUT OF
	OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
//==============================================================================

#ifndef RIPPLE_RANDOMNUMBERS_H
#define RIPPLE_RANDOMNUMBERS_H

/** Cryptographically secure random number source.
*/
class RandomNumbers
{
public:
    /** Retrieve the instance of the generator.
    */
    static RandomNumbers& getInstance ();

    /** Initialize the generator.

        If the generator is not manually initialized, it will be
        automatically initialized on first use. If automatic initialization
        fails, an exception is thrown.

        @return `true` if enough entropy could be retrieved.
    */
    bool initialize ();

    /** Generate secure random numbers.

        The generated data is suitable for cryptography.

        @invariant The destination buffer must be large enough or
                   undefined behavior results.

        @param destinationBuffer The place to store the bytes.
        @param numberOfBytes The number of bytes to generate.
    */
    void fillBytes (void* destinationBuffer, int numberOfBytes);

    /** Generate secure random numbers.

        The generated data is suitable for cryptography.

        Fills the memory for the object with random numbers.
        This is a type-safe alternative to the function above.

        @param object A pointer to the object to fill.

        @tparam T The type of `object`

        @note Undefined behavior results if `T` is not a POD type.
    */
    template <class T>
    void fill (T* object)
    {
        fillBytes (object, sizeof (T));
    }

private:
    RandomNumbers ();

    ~RandomNumbers ();

    bool platformAddEntropy ();

    void platformAddPerformanceMonitorEntropy ();

private:
    bool m_initialized;
};

#endif