/**************************************************************************\
|
|    Copyright (C) 2009 Marc Stevens
|
|    This program is free software: you can redistribute it and/or modify
|    it under the terms of the GNU General Public License as published by
|    the Free Software Foundation, either version 3 of the License, or
|    (at your option) any later version.
|
|    This program is distributed in the hope that it will be useful,
|    but WITHOUT ANY WARRANTY; without even the implied warranty of
|    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
|    GNU General Public License for more details.
|
|    You should have received a copy of the GNU General Public License
|    along with this program.  If not, see <http://www.gnu.org/licenses/>.
|
\**************************************************************************/

#include <time.h>
#include <iostream>
#include "rng.hpp"

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>    // open
#include <unistd.h>   // read, close
namespace hashclash {
    void getosrnd(uint32 buf[256])
    {
        int fd;
        if ((fd = open("/dev/urandom", O_RDONLY)) < 0) return;
        read(fd, reinterpret_cast<char*>(buf), 256*4);
        close(fd);
    }
}


namespace hashclash {

    void getosrnd(uint32 buf[256]);

    uint32 seedd;
    uint32 seed32_1;
    uint32 seed32_2;
    uint32 seed32_3;
    uint32 seed32_4;

    void seed(uint32 s)
    {
        seedd = 0;
        seed32_1 = s;
        seed32_2 = 2;
        seed32_3 = 3;
        seed32_4 = 4;
        for (unsigned i = 0; i < 0x1000; ++i)
            xrng128();
    }

    void seed(uint32* sbuf, unsigned len)
    {
        seedd = 0;
        seed32_1 = 1;
        seed32_2 = 2;
        seed32_3 = 3;
        seed32_4 = 4;
        for (unsigned i = 0; i < len; ++i)
        {
            seed32_1 ^= sbuf[i];
            xrng128();
        }
        for (unsigned i = 0; i < 0x1000; ++i)
            xrng128();
    }

    void addseed(uint32 s)
    {
        xrng128();
        seed32_1 ^= s;
        xrng128();
    }

    void addseed(const uint32* sbuf, unsigned len)
    {
        xrng128();
        for (unsigned i = 0; i < len; ++i)
        {
            seed32_1 ^= sbuf[i];
            xrng128();
        }
    }

    struct hashclash_rng__init {
        hashclash_rng__init()
        {
            seed(uint32(time(NULL)));
            uint32 rndbuf[256]; // uninitialized on purpose
            addseed(rndbuf, 256);
            getosrnd(rndbuf);
            addseed(rndbuf, 256);
        }
    };
    hashclash_rng__init hashclash_rng__init__now;

    void hashclash_rng_hpp_init()
    {
        hashclash_rng__init here;
    }

} // namespace hashclash