option.h

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/*
 * option.h -- helpers for handling options in CoAP PDUs
 *
 * Copyright (C) 2010-2013 Olaf Bergmann <bergmann@tzi.org>
 *
 * This file is part of the CoAP library libcoap. Please see README for terms
 * of use.
 */

#ifndef _COAP_OPTION_H_
#define _COAP_OPTION_H_

#include "bits.h"
#include "pdu.h"

typedef unsigned char coap_opt_t;
#define PCHAR(p) ((coap_opt_t *)(p))

typedef struct {
  unsigned short delta;
  size_t length;
  unsigned char *value;
} coap_option_t;

size_t coap_opt_parse(const coap_opt_t *opt,
                      size_t length,
                      coap_option_t *result);

size_t coap_opt_size(const coap_opt_t *opt);

#define COAP_OPT_SIZE(opt) coap_opt_size(opt)

coap_opt_t *options_start(coap_pdu_t *pdu);

#define options_next(opt) \
  ((coap_opt_t *)((unsigned char *)(opt) + COAP_OPT_SIZE(opt)))

#define COAP_OPT_FILTER_SHORT 6

#define COAP_OPT_FILTER_LONG  2

/* Ensure that COAP_OPT_FILTER_SHORT and COAP_OPT_FILTER_LONG are set
 * correctly. */
#if (COAP_OPT_FILTER_SHORT + COAP_OPT_FILTER_LONG > 16)
#error COAP_OPT_FILTER_SHORT + COAP_OPT_FILTER_LONG must be less or equal 16
#endif /* (COAP_OPT_FILTER_SHORT + COAP_OPT_FILTER_LONG > 16) */

#define COAP_OPT_FILTER_SIZE                    \
  (((COAP_OPT_FILTER_SHORT + 1) >> 1) + COAP_OPT_FILTER_LONG) +1

typedef uint16_t coap_opt_filter_t[COAP_OPT_FILTER_SIZE];

#define COAP_OPT_ALL NULL

static inline void
coap_option_filter_clear(coap_opt_filter_t f) {
  memset(f, 0, sizeof(coap_opt_filter_t));
}

int coap_option_filter_set(coap_opt_filter_t filter, unsigned short type);

int coap_option_filter_unset(coap_opt_filter_t filter, unsigned short type);

int coap_option_filter_get(const coap_opt_filter_t filter, unsigned short type);

inline static int
coap_option_setb(coap_opt_filter_t filter, unsigned short type) {
  return coap_option_filter_set(filter, type) ? 1 : -1;
}

inline static int
coap_option_clrb(coap_opt_filter_t filter, unsigned short type) {
  return coap_option_filter_unset(filter, type) ? 1 : -1;
}

inline static int
coap_option_getb(const coap_opt_filter_t filter, unsigned short type) {
  return coap_option_filter_get(filter, type);
}

typedef struct {
  size_t length;                
  unsigned short type;          
  unsigned int bad:1;           
  unsigned int filtered:1;      
  coap_opt_t *next_option;      
  coap_opt_filter_t filter;     
} coap_opt_iterator_t;

coap_opt_iterator_t *coap_option_iterator_init(coap_pdu_t *pdu,
                                               coap_opt_iterator_t *oi,
                                               const coap_opt_filter_t filter);

coap_opt_t *coap_option_next(coap_opt_iterator_t *oi);

coap_opt_t *coap_check_option(coap_pdu_t *pdu,
                              unsigned short type,
                              coap_opt_iterator_t *oi);

size_t coap_opt_setheader(coap_opt_t *opt,
                          size_t maxlen,
                          unsigned short delta,
                          size_t length);

size_t coap_opt_encode(coap_opt_t *opt,
                       size_t n,
                       unsigned short delta,
                       const unsigned char *val,
                       size_t length);

unsigned short coap_opt_delta(const coap_opt_t *opt);

#define COAP_OPT_DELTA(opt) coap_opt_delta(opt)

#define COAP_OPT_SETDELTA(opt,val) \
  coap_opt_encode((opt), COAP_MAX_PDU_SIZE, (val), NULL, 0)

unsigned short coap_opt_length(const coap_opt_t *opt);

#define COAP_OPT_LENGTH(opt) coap_opt_length(opt)

unsigned char *coap_opt_value(coap_opt_t *opt);

#define COAP_OPT_VALUE(opt) coap_opt_value((coap_opt_t *)opt)

#endif /* _OPTION_H_ */