#include "cryptrc4.h"

void swap(RC4_INT &a, RC4_INT &b)
{
    RC4_INT tmp;

    tmp = a;
    a = b;
    b = tmp;
}

CryptRc4::CryptRc4()
{

}

void CryptRc4::rc4SetKey(QByteArray key)
{
    RC4_set_key(&m_rc4Key, key.length(), (const unsigned char *) key.data());
}

void CryptRc4::rc4SetKeyOwn(QByteArray key)
{
    m_rc4Key.x = 0;
    m_rc4Key.y = 0;

    for (int i = 0; i < 256; i++)
    {
        m_rc4Key.data[i] = i;
    }

    RC4_INT j = 0;

    for (int i = 0; i < 256; i++)
    {
        j = (j + m_rc4Key.data[i] + key[i % key.length()]) % 256;
        swap(m_rc4Key.data[i], m_rc4Key.data[j]);
    }
}

QByteArray CryptRc4::rc4Run(QByteArray clear)
{
    QByteArray crypt(clear);
    RC4(&m_rc4Key, clear.length(), (const unsigned char *) clear.data(),
        (unsigned char *) crypt.data());
    return crypt;
}

QByteArray CryptRc4::rc4RunOwn(QByteArray clear)
{
    QByteArray crypt(clear);

    RC4_INT i = 0;
    RC4_INT j = 0;

    for (int k = 0; k < crypt.length(); k++)
    {
        i = (i + 1) % 256;
        j = (j + m_rc4Key.data[i]) % 256;

        swap(m_rc4Key.data[i], m_rc4Key.data[j]);

        crypt[k] = crypt[k] ^ m_rc4Key.data[(m_rc4Key.data[i] + m_rc4Key.data[j]) %
                                            256];
    }

    return crypt;
}