/*

 * 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/cast.h>

#include "cast_lcl.h"

/*

 * The input and output encrypted as though 64bit ofb mode is being used.

 * The extra state information to record how much of the 64bit block we have

 * used is contained in *num;

 */

void CAST_ofb64_encrypt(const unsigned char *in, unsigned char *out,

                        long length, const CAST_KEY *schedule,

                        unsigned char *ivec, int *num)

{

    register CAST_LONG v0, v1, t;

    register int n = *num;

    register long l = length;

    unsigned char d[8];

    register char *dp;

    CAST_LONG ti[2];

    unsigned char *iv;

    int save = 0;

    iv = ivec;

    n2l(iv, v0);

    n2l(iv, v1);

    ti[0] = v0;

    ti[1] = v1;

    dp = (char *)d;

    l2n(v0, dp);

    l2n(v1, dp);

    while (l--) {

        if (n == 0) {

            CAST_encrypt((CAST_LONG *)ti, schedule);

            dp = (char *)d;

            t = ti[0];

            l2n(t, dp);

            t = ti[1];

            l2n(t, dp);

            save++;

        }

        *(out++) = *(in++) ^ d[n];

        n = (n + 1) & 0x07;

    }

    if (save) {

        v0 = ti[0];

        v1 = ti[1];

        iv = ivec;

        l2n(v0, iv);

        l2n(v1, iv);

    }

    t = v0 = v1 = ti[0] = ti[1] = 0;

    *num = n;

}