Reimplement AES_ofb128_encrypt.

/* crypto/aes/aes_ofb.c -*- mode:C; c-file-style: "eay" -*- */

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

 * Copyright (c) 1998-2002 The OpenSSL Project.  All rights reserved.

 * Copyright (c) 2002-2006 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

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

 *

 */

/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)

 * All rights reserved.

 *

 * This package is an SSL implementation written

 * by Eric Young (eay@cryptsoft.com).

 * The implementation was written so as to conform with Netscapes SSL.

 * 

 * This library is free for commercial and non-commercial use as long as

 * the following conditions are aheared to.  The following conditions

 * apply to all code found in this distribution, be it the RC4, RSA,

 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation

 * included with this distribution is covered by the same copyright terms

 * except that the holder is Tim Hudson (tjh@cryptsoft.com).

 * 

 * Copyright remains Eric Young's, and as such any Copyright notices in

 * the code are not to be removed.

 * If this package is used in a product, Eric Young should be given attribution

 * as the author of the parts of the library used.

 * This can be in the form of a textual message at program startup or

 * in documentation (online or textual) provided with the package.

 * 

 * 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 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 acknowledgement:

 *    "This product includes cryptographic software written by

 *     Eric Young (eay@cryptsoft.com)"

 *    The word 'cryptographic' can be left out if the rouines from the library

 *    being used are not cryptographic related :-).

 * 4. If you include any Windows specific code (or a derivative thereof) from 

 *    the apps directory (application code) you must include an acknowledgement:

 *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"

 * 

 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND

 * ANY EXPRESS 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 AUTHOR OR 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

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 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF

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 * The licence and distribution terms for any publically available version or

 * derivative of this code cannot be changed.  i.e. this code cannot simply be

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 * [including the GNU Public Licence.]

 */

#ifndef AES_DEBUG

# ifndef NDEBUG

#include <openssl/aes.h>

#include "aes_locl.h"

#define STRICT_ALIGNMENT

#if defined(__i386) || defined(__i386__) || \

    defined(__x86_64) || defined(__x86_64__) || \

    defined(_M_IX86) || defined(_M_AMD64) || defined(_M_X64)

#  undef STRICT_ALIGNMENT

#endif

/* 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 AES_ofb128_encrypt(const unsigned char *in, unsigned char *out,

	const unsigned long length, const AES_KEY *key,

	unsigned long length, const AES_KEY *key,

	unsigned char *ivec, int *num) {

	unsigned int n;

	unsigned long l=length;

	unsigned long l=0;

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

	n = *num;

	while (l--) {

#if !defined(OPENSSL_SMALL_FOOTPRINT)

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

		if (n) {

			while (length) {

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

				length--;

				if(!(n = (n + 1) % AES_BLOCK_SIZE))

					break;

			}

		}

#if defined(STRICT_ALIGNMENT)

		if (((size_t)in|(size_t)out|(size_t)ivec)%sizeof(size_t) != 0)

			break;

#endif

		while ((l + AES_BLOCK_SIZE) <= length) {

			unsigned int i;

			AES_encrypt(ivec, ivec, key);

			for (i=0;i<AES_BLOCK_SIZE;i+=sizeof(size_t)) {

				*(size_t*)(out+l+i) =

				*(size_t*)(ivec+i) ^ *(size_t*)(in+l+i);

			}

			l += AES_BLOCK_SIZE;

		}

		if (l < length) {

			AES_encrypt(ivec, ivec, key);

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

				l++; n++;

			} while (l < length);

		}

		*num = n;

		return;

	} while(0);

#endif

	/* this code would be commonly eliminated by x86* compiler */

	while (l<length) {

		if (n == 0) {

			AES_encrypt(ivec, ivec, key);

		}

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

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

		l++;

		n = (n+1) % AES_BLOCK_SIZE;

	}