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50 lines
1.5 KiB
C
50 lines
1.5 KiB
C
/* encode.h -- encoding and decoding of CoAP data types
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*
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* (c) 2010 Olaf Bergmann <bergmann@tzi.org>, Carsten Bormann
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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)
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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 N 8
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#define E 4
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#define HIBIT (1 << (N - 1))
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#define EMASK ((1 << E) - 1)
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#define MMASK ((1 << N) - 1 - EMASK)
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#define MAX_VALUE ( (1 << N) - (1 << E) ) * (1 << ((1 << E) - 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) - N, (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) - N, (s = (((v + ((1<<E<<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
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* sequence 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
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* buffer of sufficient length to store the encoded bytes. val is
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* the value to encode. Returns the number of bytes used to encode
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* 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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