1 /* 2 * encode.h -- encoding and decoding of CoAP data types 3 * 4 * Copyright (C) 2010-2012 Olaf Bergmann <bergmann@tzi.org> 5 * 6 * This file is part of the CoAP library libcoap. Please see README for terms 7 * of use. 8 */ 9 10 #ifndef _COAP_ENCODE_H_ 11 #define _COAP_ENCODE_H_ 12 13 #if (BSD >= 199103) || defined(WITH_CONTIKI) 14 # include <string.h> 15 #else 16 # include <strings.h> 17 #endif 18 19 #define Nn 8 /* duplicate definition of N if built on sky motes */ 20 #define E 4 21 #define HIBIT (1 << (Nn - 1)) 22 #define EMASK ((1 << E) - 1) 23 #define MMASK ((1 << Nn) - 1 - EMASK) 24 #define MAX_VALUE ( (1 << Nn) - (1 << E) ) * (1 << ((1 << E) - 1)) 25 26 #define COAP_PSEUDOFP_DECODE_8_4(r) (r < HIBIT ? r : (r & MMASK) << (r & EMASK)) 27 28 #ifndef HAVE_FLS 29 /* include this only if fls() is not available */ 30 extern int coap_fls(unsigned int i); 31 #else 32 #define coap_fls(i) fls(i) 33 #endif 34 35 /* ls and s must be integer variables */ 36 #define COAP_PSEUDOFP_ENCODE_8_4_DOWN(v,ls) (v < HIBIT ? v : (ls = coap_fls(v) - Nn, (v >> ls) & MMASK) + ls) 37 #define COAP_PSEUDOFP_ENCODE_8_4_UP(v,ls,s) (v < HIBIT ? v : (ls = coap_fls(v) - Nn, (s = (((v + ((1<<E<<ls)-1)) >> ls) & MMASK)), s == 0 ? HIBIT + ls + 1 : s + ls)) 38 39 /** 40 * Decodes multiple-length byte sequences. buf points to an input byte sequence 41 * of length len. Returns the decoded value. 42 */ 43 unsigned int coap_decode_var_bytes(unsigned char *buf,unsigned int len); 44 45 /** 46 * Encodes multiple-length byte sequences. buf points to an output buffer of 47 * sufficient length to store the encoded bytes. val is the value to encode. 48 * Returns the number of bytes used to encode val or 0 on error. 49 */ 50 unsigned int coap_encode_var_bytes(unsigned char *buf, unsigned int val); 51 52 #endif /* _COAP_ENCODE_H_ */ 53
