Reimplement AES_ofb128_encrypt.

crypto/aes/aes_ofb.c

 /* 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
@@ -48,62 +48,6 @@
  * ====================================================================
  *
  */
-/* 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
- * 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.
- * 
- * 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
- * copied and put under another distribution licence
- * [including the GNU Public Licence.]
- */
 
 #ifndef AES_DEBUG
 # ifndef NDEBUG
@@ -115,26 +59,70 @@
 #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;
 	}