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/* parse.c */
/* nettle, low-level cryptographics library
*
* Copyright (C) 2002, 2003 Niels Möller
*
* The nettle library 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 2.1 of the License, or (at your
* option) any later version.
*
* The nettle library 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 the nettle library; see the file COPYING.LIB. If not, write to
* the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
* MA 02111-1307, USA.
*/
#if HAVE_CONFIG_H
# include "config.h"
#endif
#include <assert.h>
#include <stdlib.h>
#include "parse.h"
#include "input.h"
void
sexp_compound_token_init(struct sexp_compound_token *token)
{
token->type = 0;
nettle_buffer_init(&token->display);
nettle_buffer_init(&token->string);
}
void
sexp_compound_token_clear(struct sexp_compound_token *token)
{
nettle_buffer_clear(&token->display);
nettle_buffer_clear(&token->string);
}
void
sexp_parse_init(struct sexp_parser *parser,
struct sexp_input *input,
enum sexp_mode mode)
{
parser->input = input;
parser->mode = mode;
/* Start counting with 1 for the top level, to make comparisons
* between transport and level simpler.
*
* FIXME: Is that trick ugly? */
parser->level = 1;
parser->transport = 0;
}
/* Get next token, and check that it is of the expected kind. */
static void
sexp_check_token(struct sexp_parser *parser,
enum sexp_token token,
struct nettle_buffer *string)
{
sexp_get_token(parser->input,
parser->transport ? SEXP_CANONICAL : parser->mode,
string);
if (parser->input->token != token)
die("Syntax error.\n");
}
/* Performs further processing of the input, in particular display
* types and transport decoding.
*
* This is complicated a little by the requirement that a
* transport-encoded block, {xxxxx}, must include exactly one
* expression. We check at the end of strings and list whether or not
* we should expect a SEXP_CODING_END as the next token. */
void
sexp_parse(struct sexp_parser *parser,
struct sexp_compound_token *token)
{
for (;;)
{
sexp_get_token(parser->input,
parser->transport ? SEXP_CANONICAL : parser->mode,
&token->string);
switch(parser->input->token)
{
case SEXP_LIST_END:
if (parser->level == parser->transport)
die("Unmatched end of list in transport encoded data.\n");
parser->level--;
if (!parser->level)
die("Unmatched end of list.\n");
token->type = SEXP_LIST_END;
check_transport_end:
if (parser->level == parser->transport)
{
sexp_check_token(parser, SEXP_CODING_END, &token->string);
assert(parser->transport);
assert(parser->level == parser->transport);
parser->level--;
parser->transport = 0;
}
return;
case SEXP_EOF:
if (parser->level > 1)
die("Unexpected end of file.\n");
token->type = SEXP_EOF;
return;
case SEXP_LIST_START:
parser->level++;
token->type = SEXP_LIST_START;
return;
case SEXP_DISPLAY_START:
sexp_check_token(parser, SEXP_STRING, &token->display);
sexp_check_token(parser, SEXP_DISPLAY_END, &token->display);
sexp_check_token(parser, SEXP_STRING, &token->string);
token->type = SEXP_DISPLAY;
goto check_transport_end;
case SEXP_STRING:
token->type = SEXP_STRING;
goto check_transport_end;
case SEXP_COMMENT:
token->type = SEXP_COMMENT;
return;
case SEXP_TRANSPORT_START:
if (parser->mode == SEXP_CANONICAL)
die("Base64 not allowed in canonical mode.\n");
parser->level++;
parser->transport = parser->level;
continue;
case SEXP_CODING_END:
die("Unexpected end of transport encoding.\n");
default:
/* Internal error. */
abort();
}
}
}
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