/*

 * Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved.

 *

 * Licensed under the OpenSSL license (the "License").  You may not use

 * this file except in compliance with the License.  You can obtain a copy

 * in the file LICENSE in the source distribution or at

 * https://www.openssl.org/source/license.html

 */

#include <openssl/rc2.h>

#include "rc2_local.h"

void RC2_cbc_encrypt(const unsigned char *in, unsigned char *out, long length,

                     RC2_KEY *ks, unsigned char *iv, int encrypt)

{

    register unsigned long tin0, tin1;

    register unsigned long tout0, tout1, xor0, xor1;

    register long l = length;

    unsigned long tin[2];

    if (encrypt) {

        c2l(iv, tout0);

        c2l(iv, tout1);

        iv -= 8;

        for (l -= 8; l >= 0; l -= 8) {

            c2l(in, tin0);

            c2l(in, tin1);

            tin0 ^= tout0;

            tin1 ^= tout1;

            tin[0] = tin0;

            tin[1] = tin1;

            RC2_encrypt(tin, ks);

            tout0 = tin[0];

            l2c(tout0, out);

            tout1 = tin[1];

            l2c(tout1, out);

        }

        if (l != -8) {

            c2ln(in, tin0, tin1, l + 8);

            tin0 ^= tout0;

            tin1 ^= tout1;

            tin[0] = tin0;

            tin[1] = tin1;

            RC2_encrypt(tin, ks);

            tout0 = tin[0];

            l2c(tout0, out);

            tout1 = tin[1];

            l2c(tout1, out);

        }

        l2c(tout0, iv);

        l2c(tout1, iv);

    } else {

        c2l(iv, xor0);

        c2l(iv, xor1);

        iv -= 8;

        for (l -= 8; l >= 0; l -= 8) {

            c2l(in, tin0);

            tin[0] = tin0;

            c2l(in, tin1);

            tin[1] = tin1;

            RC2_decrypt(tin, ks);

            tout0 = tin[0] ^ xor0;

            tout1 = tin[1] ^ xor1;

            l2c(tout0, out);

            l2c(tout1, out);

            xor0 = tin0;

            xor1 = tin1;

        }

        if (l != -8) {

            c2l(in, tin0);

            tin[0] = tin0;

            c2l(in, tin1);

            tin[1] = tin1;

            RC2_decrypt(tin, ks);

            tout0 = tin[0] ^ xor0;

            tout1 = tin[1] ^ xor1;

            l2cn(tout0, tout1, out, l + 8);

            xor0 = tin0;

            xor1 = tin1;

        }

        l2c(xor0, iv);

        l2c(xor1, iv);

    }

    tin0 = tin1 = tout0 = tout1 = xor0 = xor1 = 0;

    tin[0] = tin[1] = 0;

}

void RC2_encrypt(unsigned long *d, RC2_KEY *key)

{

    int i, n;

    register RC2_INT *p0, *p1;

    register RC2_INT x0, x1, x2, x3, t;

    unsigned long l;

    l = d[0];

    x0 = (RC2_INT) l & 0xffff;

    x1 = (RC2_INT) (l >> 16L);

    l = d[1];

    x2 = (RC2_INT) l & 0xffff;

    x3 = (RC2_INT) (l >> 16L);

    n = 3;

    i = 5;

    p0 = p1 = &(key->data[0]);

    for (;;) {

        t = (x0 + (x1 & ~x3) + (x2 & x3) + *(p0++)) & 0xffff;

        x0 = (t << 1) | (t >> 15);

        t = (x1 + (x2 & ~x0) + (x3 & x0) + *(p0++)) & 0xffff;

        x1 = (t << 2) | (t >> 14);

        t = (x2 + (x3 & ~x1) + (x0 & x1) + *(p0++)) & 0xffff;

        x2 = (t << 3) | (t >> 13);

        t = (x3 + (x0 & ~x2) + (x1 & x2) + *(p0++)) & 0xffff;

        x3 = (t << 5) | (t >> 11);

        if (--i == 0) {

            if (--n == 0)

                break;

            i = (n == 2) ? 6 : 5;

            x0 += p1[x3 & 0x3f];

            x1 += p1[x0 & 0x3f];

            x2 += p1[x1 & 0x3f];

            x3 += p1[x2 & 0x3f];

        }

    }

    d[0] =

        (unsigned long)(x0 & 0xffff) | ((unsigned long)(x1 & 0xffff) << 16L);

    d[1] =

        (unsigned long)(x2 & 0xffff) | ((unsigned long)(x3 & 0xffff) << 16L);

}

void RC2_decrypt(unsigned long *d, RC2_KEY *key)

{

    int i, n;

    register RC2_INT *p0, *p1;

    register RC2_INT x0, x1, x2, x3, t;

    unsigned long l;

    l = d[0];

    x0 = (RC2_INT) l & 0xffff;

    x1 = (RC2_INT) (l >> 16L);

    l = d[1];

    x2 = (RC2_INT) l & 0xffff;

    x3 = (RC2_INT) (l >> 16L);

    n = 3;

    i = 5;

    p0 = &(key->data[63]);

    p1 = &(key->data[0]);

    for (;;) {

        t = ((x3 << 11) | (x3 >> 5)) & 0xffff;

        x3 = (t - (x0 & ~x2) - (x1 & x2) - *(p0--)) & 0xffff;

        t = ((x2 << 13) | (x2 >> 3)) & 0xffff;

        x2 = (t - (x3 & ~x1) - (x0 & x1) - *(p0--)) & 0xffff;

        t = ((x1 << 14) | (x1 >> 2)) & 0xffff;

        x1 = (t - (x2 & ~x0) - (x3 & x0) - *(p0--)) & 0xffff;

        t = ((x0 << 15) | (x0 >> 1)) & 0xffff;

        x0 = (t - (x1 & ~x3) - (x2 & x3) - *(p0--)) & 0xffff;

        if (--i == 0) {

            if (--n == 0)

                break;

            i = (n == 2) ? 6 : 5;

            x3 = (x3 - p1[x2 & 0x3f]) & 0xffff;

            x2 = (x2 - p1[x1 & 0x3f]) & 0xffff;

            x1 = (x1 - p1[x0 & 0x3f]) & 0xffff;

            x0 = (x0 - p1[x3 & 0x3f]) & 0xffff;

        }

    }

    d[0] =

        (unsigned long)(x0 & 0xffff) | ((unsigned long)(x1 & 0xffff) << 16L);

    d[1] =

        (unsigned long)(x2 & 0xffff) | ((unsigned long)(x3 & 0xffff) << 16L);

}