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/* textfilter.c
* Copyright (C) 1998,1999 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, 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"
#include "i18n.h"
#define MAX_LINELEN 19995 /* a little bit smaller than in armor.c */
/* to make sure that a warning is displayed while */
/* creating a message */
unsigned
len_without_trailing_ws( byte *line, unsigned len )
{
byte *p, *mark;
unsigned n;
for(mark=NULL, p=line, n=0; n < len; n++, p++ ) {
if( strchr(" \t\r\n", *p ) ) {
if( !mark )
mark = p;
}
else
mark = NULL;
}
return mark? (mark - line) : len;
}
static int
standard( text_filter_context_t *tfx, IOBUF a,
byte *buf, size_t size, size_t *ret_len)
{
int rc=0;
size_t len = 0;
unsigned maxlen;
assert( size > 10 );
size -= 2; /* reserve 2 bytes to append CR,LF */
while( !rc && len < size ) {
int lf_seen;
while( len < size && tfx->buffer_pos < tfx->buffer_len )
buf[len++] = tfx->buffer[tfx->buffer_pos++];
if( len >= size )
continue;
/* read the next line */
maxlen = MAX_LINELEN;
tfx->buffer_pos = 0;
tfx->buffer_len = iobuf_read_line( a, &tfx->buffer,
&tfx->buffer_size, &maxlen );
if( !maxlen )
tfx->truncated++;
if( !tfx->buffer_len ) {
if( !len )
rc = -1; /* eof */
break;
}
lf_seen = tfx->buffer[tfx->buffer_len-1] == '\n';
tfx->buffer_len = trim_trailing_ws( tfx->buffer, tfx->buffer_len );
if( lf_seen ) {
tfx->buffer[tfx->buffer_len++] = '\r';
tfx->buffer[tfx->buffer_len++] = '\n';
}
}
*ret_len = len;
return rc;
}
static int
clearsign( text_filter_context_t *tfx, IOBUF a,
byte *buf, size_t size, size_t *ret_len)
{
int rc=0;
size_t len = 0;
unsigned maxlen;
assert( size > 2 );
size -= 3; /* reserve for dash escaping and extra LF */
while( !rc && len < size ) {
unsigned n;
byte *p;
if( tfx->pending_esc ) {
buf[len++] = '-';
buf[len++] = ' ';
tfx->pending_esc = 0;
}
while( len < size && tfx->buffer_pos < tfx->buffer_len )
buf[len++] = tfx->buffer[tfx->buffer_pos++];
if( len >= size )
continue;
/* read the next line */
maxlen = MAX_LINELEN;
tfx->buffer_pos = 0;
tfx->buffer_len = iobuf_read_line( a, &tfx->buffer,
&tfx->buffer_size, &maxlen );
p = tfx->buffer;
n = tfx->buffer_len;
if( !maxlen )
tfx->truncated++;
if( !n ) { /* readline has returned eof */
/* don't hash a pending lf here because the last one is
* not part of the signed material. OpenPGP does not
* hash the last LF because it may have to add an
* extra one in case that the original material
* does not end with one. The clear signed text
* must end in a LF, so that the following armor
* line can be detected by the parser
*/
if( !tfx->pending_lf ) {
/* make sure that the file ends with a LF */
buf[len++] = '\n';
if( tfx->not_dash_escaped )
md_putc(tfx->md, '\n' );
tfx->pending_lf = 1;
}
if( !len )
rc = -1; /* eof */
break;
}
if( tfx->md ) {
if( tfx->not_dash_escaped )
md_write( tfx->md, p, n );
else {
if( tfx->pending_lf ) {
md_putc(tfx->md, '\r' );
md_putc(tfx->md, '\n' );
}
md_write( tfx->md, p, len_without_trailing_ws( p, n ) );
}
}
tfx->pending_lf = p[n-1] == '\n';
if( tfx->not_dash_escaped )
;
else if( *p == '-' )
tfx->pending_esc = 1;
else if( tfx->escape_from && n > 4 && !memcmp(p, "From ", 5 ) )
tfx->pending_esc = 1;
}
*ret_len = len;
return rc;
}
/****************
* The filter is used to make canonical text: Lines are terminated by
* CR, LF, trailing white spaces are removed.
*/
int
text_filter( void *opaque, int control,
IOBUF a, byte *buf, size_t *ret_len)
{
size_t size = *ret_len;
text_filter_context_t *tfx = opaque;
int rc=0;
if( control == IOBUFCTRL_UNDERFLOW ) {
if( tfx->clearsign )
rc = clearsign( tfx, a, buf, size, ret_len );
else
rc = standard( tfx, a, buf, size, ret_len );
}
else if( control == IOBUFCTRL_FREE ) {
if( tfx->truncated )
log_error(_("can't handle text lines longer than %d characters\n"),
MAX_LINELEN );
m_free( tfx->buffer );
tfx->buffer = NULL;
}
else if( control == IOBUFCTRL_DESC )
*(char**)buf = "text_filter";
return rc;
}
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