/* ====================================================================

 * Copyright (c) 2008 The OpenSSL Project.  All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 *

 * 1. Redistributions of source code must retain the above copyright

 *    notice, this list of conditions and the following disclaimer.

 *

 * 2. Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer in

 *    the documentation and/or other materials provided with the

 *    distribution.

 *

 * 3. All advertising materials mentioning features or use of this

 *    software must display the following acknowledgment:

 *    "This product includes software developed by the OpenSSL Project

 *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"

 *

 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to

 *    endorse or promote products derived from this software without

 *    prior written permission. For written permission, please contact

 *    openssl-core@openssl.org.

 *

 * 5. Products derived from this software may not be called "OpenSSL"

 *    nor may "OpenSSL" appear in their names without prior written

 *    permission of the OpenSSL Project.

 *

 * 6. Redistributions of any form whatsoever must retain the following

 *    acknowledgment:

 *    "This product includes software developed by the OpenSSL Project

 *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"

 *

 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY

 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR

 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR

 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,

 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT

 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;

 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)

 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,

 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)

 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED

 * OF THE POSSIBILITY OF SUCH DAMAGE.

 * ====================================================================

 *

 */

#include <openssl/crypto.h>

#include "modes_lcl.h"

#include <string.h>

#ifndef MODES_DEBUG

# ifndef NDEBUG

#  define NDEBUG

# endif

#endif

#include <assert.h>

/*

 * The input and output encrypted as though 128bit ofb mode is being used.

 * The extra state information to record how much of the 128bit block we have

 * used is contained in *num;

 */

void CRYPTO_ofb128_encrypt(const unsigned char *in, unsigned char *out,

                           size_t len, const void *key,

                           unsigned char ivec[16], int *num, block128_f block)

{

    unsigned int n;

    size_t l = 0;

    assert(in && out && key && ivec && num);

    n = *num;

#if !defined(OPENSSL_SMALL_FOOTPRINT)

    if (16 % sizeof(size_t) == 0) { /* always true actually */

        do {

            while (n && len) {

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

                --len;

                n = (n + 1) % 16;

            }

# if defined(STRICT_ALIGNMENT)

            if (((size_t)in | (size_t)out | (size_t)ivec) % sizeof(size_t) !=

                0)

                break;

# endif

            while (len >= 16) {

                (*block) (ivec, ivec, key);

                for (; n < 16; n += sizeof(size_t))

                    *(size_t *)(out + n) =

                        *(size_t *)(in + n) ^ *(size_t *)(ivec + n);

                len -= 16;

                out += 16;

                in += 16;

                n = 0;

            }

            if (len) {

                (*block) (ivec, ivec, key);

                while (len--) {

                    out[n] = in[n] ^ ivec[n];

                    ++n;

                }

            }

            *num = n;

            return;

        } while (0);

    }

    /* the rest would be commonly eliminated by x86* compiler */

#endif

    while (l < len) {

        if (n == 0) {

            (*block) (ivec, ivec, key);

        }

        out[l] = in[l] ^ ivec[n];

        ++l;

        n = (n + 1) % 16;

    }

    *num = n;

}