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gnupg/g10/mdfilter.c

78 lines
1.9 KiB
C

/* mdfilter.c - filter data and calculate a message digest
* Copyright (C) 1998, 1999, 2000, 2001 Free Software Foundation, Inc.
*
* This file is part of GnuPG.
*
* GnuPG 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.
*
* GnuPG 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
* USA.
*/
#include <config.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <assert.h>
#include "errors.h"
#include "iobuf.h"
#include "memory.h"
#include "util.h"
#include "filter.h"
/****************
* This filter is used to collect a message digest
*/
int
md_filter( void *opaque, int control,
IOBUF a, byte *buf, size_t *ret_len)
{
size_t size = *ret_len;
md_filter_context_t *mfx = opaque;
int i, rc=0;
if( control == IOBUFCTRL_UNDERFLOW ) {
if( mfx->maxbuf_size && size > mfx->maxbuf_size )
size = mfx->maxbuf_size;
i = iobuf_read( a, buf, size );
if( i == -1 ) i = 0;
if( i ) {
md_write(mfx->md, buf, i );
if( mfx->md2 )
md_write(mfx->md2, buf, i );
}
else
rc = -1; /* eof */
*ret_len = i;
}
else if( control == IOBUFCTRL_DESC )
*(char**)buf = "md_filter";
return rc;
}
void
free_md_filter_context( md_filter_context_t *mfx )
{
md_close(mfx->md);
md_close(mfx->md2);
mfx->md = NULL;
mfx->md2 = NULL;
mfx->maxbuf_size = 0;
}