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/* compress.c - compress filter
* Copyright (c) 1997 by Werner Koch (dd9jn)
*
* This file is part of G10.
*
* G10 is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* G10 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
*/
#include <config.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <assert.h>
#include <errno.h>
#include <zlib.h>
#include "util.h"
#include "memory.h"
#include "packet.h"
#include "filter.h"
#include "options.h"
static void
init_compress( compress_filter_context_t *zfx, z_stream *zs )
{
int rc;
int level;
if( opt.compress >= 0 && opt.compress <= 9 )
level = opt.compress;
else if( opt.compress == -1 )
level = Z_DEFAULT_COMPRESSION;
else if( opt.compress == 10 ) /* remove this ! */
level = 0;
else {
log_error("invalid compression level; using default level\n");
level = Z_DEFAULT_COMPRESSION;
}
if( (rc = deflateInit( zs, level )) != Z_OK ) {
log_fatal("zlib problem: %s\n", zs->msg? zs->msg :
rc == Z_MEM_ERROR ? "out of core" :
rc == Z_VERSION_ERROR ? "invalid lib version" :
"unknown error" );
}
zfx->outbufsize = 4096;
zfx->outbuf = m_alloc( zfx->outbufsize );
}
static int
do_compress( compress_filter_context_t *zfx, z_stream *zs, int flush, IOBUF a )
{
int zrc;
unsigned n;
do {
zs->next_out = zfx->outbuf;
zs->avail_out = zfx->outbufsize;
zrc = deflate( zs, flush );
if( zrc == Z_STREAM_END && flush == Z_FINISH )
;
else if( zrc != Z_OK ) {
if( zs->msg )
log_fatal("zlib deflate problem: %s\n", zs->msg );
else
log_fatal("zlib deflate problem: rc=%d\n", zrc );
}
n = zfx->outbufsize - zs->avail_out;
if( DBG_FILTER )
log_debug("deflate returned: avail_in=%u, avail_out=%u, n=%u\n",
(unsigned)zs->avail_in, (unsigned)zs->avail_out, (unsigned)n );
if( iobuf_write( a, zfx->outbuf, n ) ) {
log_debug("deflate: iobuf_write failed\n");
return G10ERR_WRITE_FILE;
}
} while( zs->avail_in || (flush == Z_FINISH && zrc != Z_STREAM_END) );
return 0;
}
static void
init_uncompress( compress_filter_context_t *zfx, z_stream *zs )
{
int rc;
/****************
* PGP uses a windowsize of 13 bits. Using a negative value for
* it forces zlib not to expect a zlib header. This is a
* undocumented feature, Peter Gutmann told me about.
*/
if( (rc = zfx->pgpmode? inflateInit2( zs, -13)
: inflateInit( zs )) != Z_OK ) {
log_fatal("zlib problem: %s\n", zs->msg? zs->msg :
rc == Z_MEM_ERROR ? "out of core" :
rc == Z_VERSION_ERROR ? "invalid lib version" :
"unknown error" );
}
zfx->inbufsize = 1024;
zfx->inbuf = m_alloc( zfx->inbufsize );
zs->avail_in = 0;
}
static int
do_uncompress( compress_filter_context_t *zfx, z_stream *zs,
IOBUF a, size_t *ret_len )
{
int zrc;
int rc=0;
size_t n;
byte *p;
int c;
if( DBG_FILTER )
log_debug("do_uncompress: avail_in=%u, avail_out=%u\n",
(unsigned)zs->avail_in, (unsigned)zs->avail_out);
do {
if( zs->avail_in < zfx->inbufsize ) {
n = zs->avail_in;
if( !n )
zs->next_in = zfx->inbuf;
for( p=zfx->inbuf+n; n < zfx->inbufsize; n++, p++ ) {
if( (c=iobuf_get(a)) == -1 )
break;
*p = c & 0xff;
}
zs->avail_in = n;
}
zrc = inflate( zs, Z_PARTIAL_FLUSH );
if( DBG_FILTER )
log_debug("inflate returned: avail_in=%u, avail_out=%u, zrc=%d\n",
(unsigned)zs->avail_in, (unsigned)zs->avail_out, zrc);
if( zrc == Z_STREAM_END )
rc = -1; /* eof FIXME: return remaining bytes until EOF */
else if( zrc != Z_OK ) {
if( zs->msg )
log_fatal("zlib inflate problem: %s\n", zs->msg );
else
log_fatal("zlib inflate problem: rc=%d\n", zrc );
}
} while( zs->avail_out && zrc != Z_STREAM_END );
*ret_len = zfx->outbufsize - zs->avail_out;
if( DBG_FILTER )
log_debug("do_uncompress: returning %u bytes\n", (unsigned)*ret_len );
return rc;
}
int
compress_filter( void *opaque, int control,
IOBUF a, byte *buf, size_t *ret_len)
{
size_t size = *ret_len;
compress_filter_context_t *zfx = opaque;
z_stream *zs = zfx->opaque;
int rc=0;
if( control == IOBUFCTRL_UNDERFLOW ) {
if( !zfx->status ) {
zs = zfx->opaque = m_alloc_clear( sizeof *zs );
init_uncompress( zfx, zs );
zfx->status = 1;
}
zs->next_out = buf;
zs->avail_out = size;
zfx->outbufsize = size; /* needed only for calculation */
rc = do_uncompress( zfx, zs, a, ret_len );
}
else if( control == IOBUFCTRL_FLUSH ) {
if( !zfx->status ) {
PACKET pkt;
PKT_compressed cd;
memset( &cd, 0, sizeof cd );
cd.len = 0;
cd.algorithm = 2; /* zlib */
init_packet( &pkt );
pkt.pkttype = PKT_COMPRESSED;
pkt.pkt.compressed = &cd;
if( build_packet( a, &pkt ))
log_bug("build_packet(PKT_COMPRESSED) failed\n");
zs = zfx->opaque = m_alloc_clear( sizeof *zs );
init_compress( zfx, zs );
zfx->status = 2;
}
zs->next_in = buf;
zs->avail_in = size;
rc = do_compress( zfx, zs, Z_NO_FLUSH, a );
}
else if( control == IOBUFCTRL_FREE ) {
if( zfx->status == 1 ) {
inflateEnd(zs);
m_free(zs);
zfx->opaque = NULL;
m_free(zfx->outbuf); zfx->outbuf = NULL;
}
else if( zfx->status == 2 ) {
zs->next_in = buf;
zs->avail_in = 0;
do_compress( zfx, zs, Z_FINISH, a );
deflateEnd(zs);
m_free(zs);
zfx->opaque = NULL;
m_free(zfx->outbuf); zfx->outbuf = NULL;
}
}
else if( control == IOBUFCTRL_DESC )
*(char**)buf = "compress_filter";
return rc;
}
/****************
* Handle a compressed packet
*/
int
handle_compressed( PKT_compressed *cd )
{
compress_filter_context_t cfx;
memset( &cfx, 0, sizeof cfx );
if( cd->algorithm == 1 )
cfx.pgpmode = 1;
else if( cd->algorithm != 2 )
return G10ERR_COMPR_ALGO;
iobuf_push_filter( cd->buf, compress_filter, &cfx );
proc_packets(cd->buf);
iobuf_pop_filter( cd->buf, compress_filter, &cfx );
#if 0
if( cd->len )
iobuf_set_limit( cd->buf, 0 ); /* disable the readlimit */
else
iobuf_clear_eof( cd->buf );
#endif
cd->buf = NULL;
return 0;
}

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Mime Type
text/x-c
Expires
Sat, May 10, 9:12 AM (7 h, 8 m)
Storage Engine
local-disk
Storage Format
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Storage Handle
25/1a/4873c7758dd2396a635673e0cc50

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