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