199 lines
7.2 KiB
C
199 lines
7.2 KiB
C
/* crypto/des/cfb_enc.c */
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/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
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* All rights reserved.
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*
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* This package is an SSL implementation written
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* by Eric Young (eay@cryptsoft.com).
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* The implementation was written so as to conform with Netscapes SSL.
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*
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* This library is free for commercial and non-commercial use as long as
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* the following conditions are aheared to. The following conditions
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* apply to all code found in this distribution, be it the RC4, RSA,
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* lhash, DES, etc., code; not just the SSL code. The SSL documentation
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* included with this distribution is covered by the same copyright terms
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* except that the holder is Tim Hudson (tjh@cryptsoft.com).
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*
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* Copyright remains Eric Young's, and as such any Copyright notices in
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* the code are not to be removed.
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* If this package is used in a product, Eric Young should be given attribution
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* as the author of the parts of the library used.
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* This can be in the form of a textual message at program startup or
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* in documentation (online or textual) provided with the package.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* "This product includes cryptographic software written by
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* Eric Young (eay@cryptsoft.com)"
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* The word 'cryptographic' can be left out if the rouines from the library
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* being used are not cryptographic related :-).
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* 4. If you include any Windows specific code (or a derivative thereof) from
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* the apps directory (application code) you must include an acknowledgement:
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* "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
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*
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* THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* The licence and distribution terms for any publically available version or
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* derivative of this code cannot be changed. i.e. this code cannot simply be
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* copied and put under another distribution licence
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* [including the GNU Public Licence.]
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*/
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#include "e_os.h"
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#include "des_locl.h"
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#include <assert.h>
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/*
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* The input and output are loaded in multiples of 8 bits. What this means is
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* that if you hame numbits=12 and length=2 the first 12 bits will be
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* retrieved from the first byte and half the second. The second 12 bits
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* will come from the 3rd and half the 4th byte.
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*/
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/*
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* Until Aug 1 2003 this function did not correctly implement CFB-r, so it
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* will not be compatible with any encryption prior to that date. Ben.
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*/
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void DES_cfb_encrypt(const unsigned char *in, unsigned char *out, int numbits,
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long length, DES_key_schedule *schedule,
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DES_cblock *ivec, int enc)
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{
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register DES_LONG d0, d1, v0, v1;
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register unsigned long l = length;
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register int num = numbits / 8, n = (numbits + 7) / 8, i, rem =
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numbits % 8;
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DES_LONG ti[2];
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unsigned char *iv;
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#ifndef L_ENDIAN
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unsigned char ovec[16];
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#else
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unsigned int sh[4];
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unsigned char *ovec = (unsigned char *)sh;
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/* I kind of count that compiler optimizes away this assertioni, */
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assert(sizeof(sh[0]) == 4); /* as this holds true for all, */
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/* but 16-bit platforms... */
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#endif
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if (numbits <= 0 || numbits > 64)
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return;
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iv = &(*ivec)[0];
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c2l(iv, v0);
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c2l(iv, v1);
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if (enc) {
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while (l >= (unsigned long)n) {
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l -= n;
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ti[0] = v0;
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ti[1] = v1;
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DES_encrypt1((DES_LONG *)ti, schedule, DES_ENCRYPT);
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c2ln(in, d0, d1, n);
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in += n;
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d0 ^= ti[0];
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d1 ^= ti[1];
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l2cn(d0, d1, out, n);
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out += n;
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/*
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* 30-08-94 - eay - changed because l>>32 and l<<32 are bad under
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* gcc :-(
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*/
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if (numbits == 32) {
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v0 = v1;
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v1 = d0;
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} else if (numbits == 64) {
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v0 = d0;
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v1 = d1;
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} else {
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#ifndef L_ENDIAN
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iv = &ovec[0];
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l2c(v0, iv);
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l2c(v1, iv);
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l2c(d0, iv);
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l2c(d1, iv);
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#else
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sh[0] = v0, sh[1] = v1, sh[2] = d0, sh[3] = d1;
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#endif
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if (rem == 0)
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memmove(ovec, ovec + num, 8);
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else
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for (i = 0; i < 8; ++i)
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ovec[i] = ovec[i + num] << rem |
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ovec[i + num + 1] >> (8 - rem);
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#ifdef L_ENDIAN
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v0 = sh[0], v1 = sh[1];
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#else
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iv = &ovec[0];
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c2l(iv, v0);
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c2l(iv, v1);
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#endif
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}
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}
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} else {
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while (l >= (unsigned long)n) {
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l -= n;
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ti[0] = v0;
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ti[1] = v1;
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DES_encrypt1((DES_LONG *)ti, schedule, DES_ENCRYPT);
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c2ln(in, d0, d1, n);
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in += n;
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/*
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* 30-08-94 - eay - changed because l>>32 and l<<32 are bad under
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* gcc :-(
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*/
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if (numbits == 32) {
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v0 = v1;
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v1 = d0;
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} else if (numbits == 64) {
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v0 = d0;
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v1 = d1;
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} else {
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#ifndef L_ENDIAN
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iv = &ovec[0];
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l2c(v0, iv);
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l2c(v1, iv);
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l2c(d0, iv);
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l2c(d1, iv);
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#else
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sh[0] = v0, sh[1] = v1, sh[2] = d0, sh[3] = d1;
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#endif
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if (rem == 0)
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memmove(ovec, ovec + num, 8);
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else
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for (i = 0; i < 8; ++i)
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ovec[i] = ovec[i + num] << rem |
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ovec[i + num + 1] >> (8 - rem);
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#ifdef L_ENDIAN
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v0 = sh[0], v1 = sh[1];
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#else
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iv = &ovec[0];
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c2l(iv, v0);
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c2l(iv, v1);
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#endif
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}
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d0 ^= ti[0];
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d1 ^= ti[1];
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l2cn(d0, d1, out, n);
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out += n;
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}
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}
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iv = &(*ivec)[0];
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l2c(v0, iv);
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l2c(v1, iv);
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v0 = v1 = d0 = d1 = ti[0] = ti[1] = 0;
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}
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