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/* sexp.h
*
* Parsing s-expressions.
*/
/* nettle, low-level cryptographics library
*
* Copyright (C) 2002 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.
*/
#ifndef NETTLE_SEXP_H_INCLUDED
#define NETTLE_SEXP_H_INCLUDED
#include <inttypes.h>
#include <stdarg.h>
enum sexp_type
{ SEXP_ATOM, SEXP_LIST, SEXP_END };
struct sexp_iterator
{
unsigned length;
const uint8_t *buffer;
/* Points at the start of the current sub expression. */
unsigned start;
/* If type is SEXP_LIST, pos points at the start of the current
* element. Otherwise, it points at the end. */
unsigned pos;
unsigned level;
enum sexp_type type;
unsigned display_length;
const uint8_t *display;
unsigned atom_length;
const uint8_t *atom;
};
/* All these functions return 1 on success, 0 on failure */
/* Initializes the iterator. */
int
sexp_iterator_first(struct sexp_iterator *iterator,
unsigned length, const uint8_t *input);
/* NOTE: Decodes the input string in place */
int
sexp_transport_iterator_first(struct sexp_iterator *iterator,
unsigned length, uint8_t *input);
int
sexp_iterator_next(struct sexp_iterator *iterator);
/* Current element must be a list. */
int
sexp_iterator_enter_list(struct sexp_iterator *iterator);
/* Skips the rest of the current list */
int
sexp_iterator_exit_list(struct sexp_iterator *iterator);
#if 0
/* Skips out of as many lists as necessary to get back to the given
* level. */
int
sexp_iterator_exit_lists(struct sexp_iterator *iterator,
unsigned level);
#endif
/* Gets start and length of the current subexpression. Implies
* sexp_iterator_next. */
const uint8_t *
sexp_iterator_subexpr(struct sexp_iterator *iterator,
unsigned *length);
int
sexp_iterator_get_uint32(struct sexp_iterator *iterator,
uint32_t *x);
/* Checks the type of the current expression, which should be a list
*
* (<type> ...)
*/
int
sexp_iterator_check_type(struct sexp_iterator *iterator,
const uint8_t *type);
const uint8_t *
sexp_iterator_check_types(struct sexp_iterator *iterator,
unsigned ntypes,
const uint8_t **types);
/* Current element must be a list. Looks up element of type
*
* (key rest...)
*
* For a matching key, the corresponding iterator is initialized
* pointing at the start of REST.
*
* On success, exits the current list.
*/
int
sexp_iterator_assoc(struct sexp_iterator *iterator,
unsigned nkeys,
const uint8_t **keys,
struct sexp_iterator *values);
/* Output functions. What is a reasonable API for this? It seems
* ugly to have to reimplement string streams. */
/* Declared for real in buffer.h */
struct nettle_buffer;
/* Returns the number of output characters, or 0 on out of memory. If
* buffer == NULL, just compute length.
*
* Format strings can contained matched parentheses, and the following
* formatting specifiers:
*
* %s String represented as unsigned length, const uint8_t *data.
*
* %t Optional display type, represented as
* unsigned display_length, const uint8_t *display,
* display == NULL means no display type.
*
* %i Non-negative small integer, uint32_t.
*
* %b Non-negative bignum, mpz_t.
*
* %l Literal string (no length added), typically a balanced
* subexpression. Represented as unsigned length, const uint8_t
* *data.
*
* Modifiers:
*
* %0 For %s, %t and %l, says that there's no length argument,
* instead the string is NUL-terminated, and there's only one
* const uint8_t * argument.
*
* FIXME: Allow literals, like "(x%b)". Allow "%(" for unbalanced
* parenthesis. */
unsigned
sexp_format(struct nettle_buffer *buffer,
const char *format, ...);
unsigned
sexp_vformat(struct nettle_buffer *buffer,
const char *format, va_list args);
/* FIXME: Add argument LINE_WIDTH. If non-zero, break lines to at most
* that width. */
unsigned
sexp_transport_format(struct nettle_buffer *buffer,
const char *format, ...);
unsigned
sexp_transport_vformat(struct nettle_buffer *buffer,
const char *format, va_list args);
#endif /* NETTLE_SEXP_H_INCLUDED */
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