text: /*
   * encode.h -- encoding and decoding of CoAP data types
   *
   * Copyright (C) 2010-2012 Olaf Bergmann <bergmann@tzi.org>
   *
   * This file is part of the CoAP library libcoap. Please see README for terms
   * of use.
   */
  
  #ifndef _COAP_ENCODE_H_
  #define _COAP_ENCODE_H_
  
  #if 1//(BSD >= 199103) || defined(WITH_CONTIKI)
  # include <string.h>
  #else
  # include <strings.h>
  #endif
  
  #define Nn 8  /* duplicate definition of N if built on sky motes */
  #define ENCODE_HEADER_SIZE 4
  #define HIBIT (1 << (Nn - 1))
  #define EMASK ((1 << ENCODE_HEADER_SIZE) - 1)
  #define MMASK ((1 << Nn) - 1 - EMASK)
  #define MAX_VALUE ( (1 << Nn) - (1 << ENCODE_HEADER_SIZE) ) * (1 << ((1 << ENCODE_HEADER_SIZE) - 1))
  
  #define COAP_PSEUDOFP_DECODE_8_4(r) (r < HIBIT ? r : (r & MMASK) << (r & EMASK))
  
  #ifndef HAVE_FLS
  /* include this only if fls() is not available */
  extern int coap_fls(unsigned int i);
  #else
  #define coap_fls(i) fls(i)
  #endif
  
  /* ls and s must be integer variables */
  #define COAP_PSEUDOFP_ENCODE_8_4_DOWN(v,ls) (v < HIBIT ? v : (ls = coap_fls(v) - Nn, (v >> ls) & MMASK) + ls)
  #define COAP_PSEUDOFP_ENCODE_8_4_UP(v,ls,s) (v < HIBIT ? v : (ls = coap_fls(v) - Nn, (s = (((v + ((1<<ENCODE_HEADER_SIZE<<ls)-1)) >> ls) & MMASK)), s == 0 ? HIBIT + ls + 1 : s + ls))
  
  /**
   * Decodes multiple-length byte sequences. buf points to an input byte sequence
   * of length len. Returns the decoded value.
   */
  unsigned int coap_decode_var_bytes(unsigned char *buf,unsigned int len);
  
  /**
   * Encodes multiple-length byte sequences. buf points to an output buffer of
   * sufficient length to store the encoded bytes. val is the value to encode.
   * Returns the number of bytes used to encode val or 0 on error.
   */
  unsigned int coap_encode_var_bytes(unsigned char *buf, unsigned int val);
  
  #endif /* _COAP_ENCODE_H_ */
  