Commit fd6af34b authored by Niels Möller's avatar Niels Möller

New file, implementing an sexp canonical syntax

formatter.

Rev: src/nettle/sexp_format.c:1.1
parent e2953184
/* sexp-output.c
*
* Writing s-expressions.
*/
/* nettle, low-level cryptographics library
*
* Copyright (C) 2002 Niels Mller
*
* 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 "sexp.h"
#include "buffer.h"
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#if HAVE_LIBGMP
# include "bignum.h"
#endif
static int
format_prefix(struct nettle_buffer *output,
unsigned length)
{
unsigned prefix_length;
char prefix[10];
/* NOTE: Using the return value of sprintf is not entirely
* portable. */
prefix_length = snprintf(prefix, sizeof(prefix), "%u:", length);
if (prefix_length >= sizeof(prefix))
return 0;
return nettle_buffer_write(buffer, prefix_length, prefix);
}
static int
format_length_string(struct nettle_buffer *buffer,
unsigned length, const char *s)
{
return format_prefix(buffer, length)
&& nettle_buffer_write(buffer, length, s);
}
static uint8_t *
format_space(struct nettle_buffer *buffer,
unsigned length)
{
return format_prefix(output, length)
? nettle_buffer_space(output, length) : NULL;
}
static int
format_string(struct nettle_buffer *buffer,
const char *s)
{
return format_length_string(buffer, strlen(s), s);
}
int
sexp_format(struct nettle_buffer *buffer, const char *format, ...)
{
va_list args;
va_start(args, format);
unsigned nesting = 0;
for (;;)
switch (*format++)
{
case '\0':
if (nesting)
{
fail:
va_end(args);
return 0;
}
else
{
va_end(args);
return 1;
}
case '(':
if (!NETTLE_BUFFER_PUTC(buffer, '('))
goto fail;
nesting++;
break;
case ')':
if (!nesting)
abort();
if (!NETTLE_BUFFER_PUTC(buffer, ')'))
goto fail;
nesting--;
break;
case '%':
switch (*format++)
{
case 's':
{
const char *s = va_arg(args, const char *);
format_string(buffer, s);
break;
}
case 'b':
{
#if HAVE_LIBGMP
const MP_INT *n = va_arg(args, const MP_INT *);
uint8_t *space;
unsigned length;
if (mpz_sgn(n) < 0)
goto fail;
length = nettle_mpz_sizeinbase_256(n);
space = format_space(buffer, length);
if (!space)
goto fail;
nettle_mpz_get_str_256(length, space, n);
#else /* ! HAVE_LIBGMP */
abort();
#endif /* ! HAVE_LIBGMP */
break;
}
default:
abort();
}
}
}
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