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119 lines
3.6 KiB
C
119 lines
3.6 KiB
C
/*
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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) || defined(_WIN32)
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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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#include <stdint.h>
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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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#ifndef HAVE_FLSLL
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/* include this only if flsll() is not available */
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extern int coap_flsll(long long i);
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#else
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#define coap_flsll(i) flsll(i)
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#endif
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/**
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* @defgroup encode Encode / Decode API
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* API functions for endoding/decoding CoAP options.
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* @{
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*/
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/**
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* Decodes multiple-length byte sequences. @p buf points to an input byte
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* sequence of length @p length. Returns the up to 4 byte decoded value.
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*
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* @param buf The input byte sequence to decode from
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* @param length The length of the input byte sequence
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*
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* @return The decoded value
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*/
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unsigned int coap_decode_var_bytes(const uint8_t *buf, size_t length);
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/**
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* Decodes multiple-length byte sequences. @p buf points to an input byte
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* sequence of length @p length. Returns the up to 8 byte decoded value.
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*
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* @param buf The input byte sequence to decode from
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* @param length The length of the input byte sequence
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*
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* @return The decoded value
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*/
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uint64_t coap_decode_var_bytes8(const uint8_t *buf, size_t length);
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/**
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* Encodes multiple-length byte sequences. @p buf points to an output buffer of
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* sufficient length to store the encoded bytes. @p value is the 4 byte value
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* to encode.
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* Returns the number of bytes used to encode @p value or 0 on error.
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*
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* @param buf The output buffer to encode into
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* @param length The output buffer size to encode into (must be sufficient)
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* @param value The value to encode into the buffer
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*
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* @return The number of bytes used to encode @p value or @c 0 on error.
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*/
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unsigned int coap_encode_var_safe(uint8_t *buf,
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size_t length,
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unsigned int value);
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/**
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* Encodes multiple-length byte sequences. @p buf points to an output buffer of
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* sufficient length to store the encoded bytes. @p value is the 8 byte value
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* to encode.
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* Returns the number of bytes used to encode @p value or 0 on error.
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*
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* @param buf The output buffer to encode into
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* @param length The output buffer size to encode into (must be sufficient)
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* @param value The value to encode into the buffer
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*
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* @return The number of bytes used to encode @p value or @c 0 on error.
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*/
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unsigned int coap_encode_var_safe8(uint8_t *buf,
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size_t length,
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uint64_t value);
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/** @} */
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/**
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* @deprecated Use coap_encode_var_safe() instead.
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* Provided for backward compatibility. As @p value has a
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* maximum value of 0xffffffff, and buf is usually defined as an array, it
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* is unsafe to continue to use this variant if buf[] is less than buf[4].
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*
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* For example
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* char buf[1],oops;
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* ..
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* coap_encode_var_bytes(buf, 0xfff);
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* would cause oops to get overwritten. This error can only be found by code
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* inspection.
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* coap_encode_var_safe(buf, sizeof(buf), 0xfff);
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* would catch this error at run-time and should be used instead.
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*/
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COAP_STATIC_INLINE COAP_DEPRECATED int
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coap_encode_var_bytes(uint8_t *buf, unsigned int value
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) {
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return (int)coap_encode_var_safe(buf, sizeof(value), value);
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}
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#endif /* COAP_ENCODE_H_ */
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