pcompress/bsdiff/bspatch.c

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2013-03-07 14:56:48 +00:00
/*
* This file is a part of Pcompress, a chunked parallel multi-
* algorithm lossless compression and decompression program.
*
* Copyright (C) 2012-2013 Moinak Ghosh. All rights reserved.
* Use is subject to license terms.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 3 of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this program.
* If not, see <http://www.gnu.org/licenses/>.
*
* moinakg@belenix.org, http://moinakg.wordpress.com/
*
*/
/*-
* Copyright 2003-2005 Colin Percival
* All rights reserved
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted providing 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 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.
*/
#if 0
__FBSDID("$FreeBSD: src/usr.bin/bsdiff/bspatch/bspatch.c,v 1.1 2005/08/06 01:59:06 cperciva Exp $");
#endif
#include <bzlib.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <err.h>
#include <unistd.h>
#include <fcntl.h>
#include <allocator.h>
#include <utils.h>
#define __IN_BSPATCH__
#include "bscommon.h"
static int32_t
valini32(u_char *buf)
{
return ntohl(I32_P(buf));
}
bsize_t
get_bsdiff_sz(u_char *pbuf) {
bsize_t newsize;
bsize_t lzctrllen, ctrllen, lzdatalen, datalen, lzextralen, extralen;
int hdrsz;
hdrsz = 4*7;
lzctrllen = valini32(pbuf);
ctrllen = valini32(pbuf+4);
lzdatalen = valini32(pbuf+4*2);
datalen = valini32(pbuf+4*3);
lzextralen = valini32(pbuf+4*4);
extralen = valini32(pbuf+4*5);
newsize = valini32(pbuf+4*6);
return (lzctrllen + lzdatalen + lzextralen + hdrsz);
}
int
bspatch(u_char *pbuf, u_char *oldbuf, bsize_t oldsize, u_char *newbuf, bsize_t *_newsize)
{
bsize_t newsize;
bsize_t lzctrllen, ctrllen, lzdatalen, datalen, lzextralen, extralen;
u_char buf[8];
u_char *diffdata, *extradata, *ctrldata;
bsize_t oldpos,newpos;
bsize_t ctrl[3];
bsize_t lenread;
bsize_t i;
bufio_t cpf, dpf, epf;
int hdrsz, rv;
unsigned int len;
/*
File format:
0 4 compressed length of ctrl block (X)
4 4 actual length of ctrl block (X)
8 4 compressed length of diff block (Y)
12 4 actual length of diff block
16 4 compressed length of extra block (Z)
20 4 actual length of extra block
24 4 length of new file
28 X ZRLE?(control block)
28+X Y ZRLE(diff block)
28+X+Y Z ZRLE(extra block)
with control block a set of triples (x,y,z) meaning "add x bytes
from oldfile to x bytes from the diff block; copy y bytes from the
extra block; seek forwards in oldfile by z bytes".
*/
hdrsz = 4*7;
rv = 1;
/* Read lengths from header first. */
lzctrllen = valini32(pbuf);
ctrllen = valini32(pbuf+4);
lzdatalen = valini32(pbuf+4*2);
datalen = valini32(pbuf+4*3);
lzextralen = valini32(pbuf+4*4);
extralen = valini32(pbuf+4*5);
newsize = valini32(pbuf+4*6);
if((ctrllen<0) || (lzdatalen<0) || (newsize<0) || (lzextralen<0)) {
log_msg(LOG_ERR, 0, "1: Corrupt patch\n");
return (0);
}
if (newsize > *_newsize) {
log_msg(LOG_ERR, 0, "Output buffer too small.\n");
return (0);
}
*_newsize = newsize;
/* Allocate buffers. */
diffdata = (u_char *)slab_alloc(NULL, datalen);
extradata = (u_char *)slab_alloc(NULL, extralen);
if (diffdata == NULL || extradata == NULL) {
log_msg(LOG_ERR, 0, "bspatch: Out of memory.\n");
if (diffdata) slab_free(NULL, diffdata);
if (extradata) slab_free(NULL, extradata);
return (0);
}
/* Decompress ctrldata, diffdata and extradata. */
if (lzctrllen < ctrllen) {
/* Ctrl data will be RLE-d if RLE size is less. */
ctrldata = (u_char *)slab_alloc(NULL, ctrllen);
if (ctrldata == NULL) {
log_msg(LOG_ERR, 0, "bspatch: Out of memory.\n");
slab_free(NULL, diffdata);
slab_free(NULL, extradata);
return (0);
}
len = ctrllen;
if (zero_rle_decode(pbuf + hdrsz, lzctrllen, ctrldata, &len) == -1 ||
len != ctrllen) {
log_msg(LOG_ERR, 0, "bspatch: Failed to decompress control data.\n");
rv = 0;
goto out;
}
} else {
ctrldata = pbuf + hdrsz;
}
len = datalen;
if (zero_rle_decode(pbuf + hdrsz + lzctrllen, lzdatalen, diffdata, &len) == -1 ||
len != datalen) {
log_msg(LOG_ERR, 0, "bspatch: Failed to decompress diff data.\n");
rv = 0;
goto out;
}
datalen = len;
len = extralen;
if (len > 0) {
if (extralen == lzextralen) {
memcpy(extradata, pbuf + hdrsz + lzctrllen + lzdatalen, lzextralen);
} else if (zero_rle_decode(pbuf + hdrsz + lzctrllen + lzdatalen, lzextralen, extradata, &len) == -1 ||
len != extralen) {
log_msg(LOG_ERR, 0, "bspatch: Failed to decompress extra data.\n");
rv = 0;
goto out;
}
}
extralen = len;
BUFOPEN(&cpf, ctrldata, ctrllen);
BUFOPEN(&dpf, diffdata, datalen);
BUFOPEN(&epf, extradata, extralen);
oldpos=0;newpos=0;
while(newpos<newsize) {
/* Read control data */
for(i=0;i<=2;i++) {
lenread = BUFREAD(&cpf, buf, 4);
if (lenread < 4) {
log_msg(LOG_ERR, 0, "2: Corrupt diff data\n");
rv = 0;
goto out;
}
ctrl[i]=valini32(buf);
};
/* Sanity-check */
if(newpos+ctrl[0]>newsize) {
log_msg(LOG_ERR, 0, "3: Corrupt diff data\n");
rv = 0;
goto out;
}
/* Read diff string */
lenread = BUFREAD(&dpf, newbuf + newpos, ctrl[0]);
if (lenread < ctrl[0]) {
log_msg(LOG_ERR, 0, "4: Corrupt diff data\n");
rv = 0;
goto out;
}
/* Add old data to diff string */
for(i=0;i<ctrl[0];i++)
if((oldpos+i>=0) && (oldpos+i<oldsize))
newbuf[newpos+i]+=oldbuf[oldpos+i];
/* Adjust pointers */
newpos+=ctrl[0];
oldpos+=ctrl[0];
/* Sanity-check */
if(newpos+ctrl[1]>newsize) {
log_msg(LOG_ERR, 0, "5: Corrupt diff data\n");
rv = 0;
goto out;
}
/* Read extra string */
lenread = BUFREAD(&epf, newbuf + newpos, ctrl[1]);
if (lenread < ctrl[1]) {
log_msg(LOG_ERR, 0, "6: Corrupt diff data\n");
rv = 0;
goto out;
}
/* Adjust pointers */
newpos+=ctrl[1];
oldpos+=ctrl[2];
};
out:
if (lzctrllen < ctrllen)
slab_free(NULL, ctrldata);
slab_free(NULL, diffdata);
slab_free(NULL, extradata);
return (rv);
}