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RIOT/sys/include/cbor.h

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/*
* Copyright (C) 2014 Freie Universität Berlin
* Copyright (C) 2014 Kevin Funk <kfunk@kde.org>
* Copyright (C) 2014 Jana Cavojska <jana.cavojska9@gmail.com>
*
* This file is subject to the terms and conditions of the GNU Lesser
* General Public License v2.1. See the file LICENSE in the top level
* directory for more details.
*/
/**
* @defgroup sys_cbor CBOR
* @ingroup sys
*
* @brief CBOR serializer/deserializer
*
* This is an implementation suited for constrained devices
* Characteristics:
* - No dynamic memory allocation (i.e. no calls to `malloc()`, `free()`) used
* throughout the implementation
* - User may allocate static buffers, this implementation uses the space
* provided by them (cf. @ref cbor_stream_t)
*
* # Supported types (categorized by major type (MT))
*
* - Major type 0 (unsigned integer): Full support. Relevant functions:
* - cbor_serialize_int(), cbor_deserialize_int()
* - cbor_serialize_uint64_t(), cbor_deserialize_uint64_t()
*
* - Major type 1 (negative integer): Full support. Relevant functions:
* - cbor_serialize_int(), cbor_deserialize_int()
* - cbor_serialize_int64_t(), cbor_deserialize_int64_t()
*
* - Major type 2 (byte string): Full support. Relevant functions:
* - cbor_serialize_byte_string(), cbor_deserialize_byte_string()
*
* - Major type 3 (unicode string): Basic support (see below). Relevant functions:
* - cbor_serialize_unicode_string(), cbor_deserialize_unicode_string()
*
* - Major type 4 (array of data items): Full support. Relevant functions:
* - cbor_serialize_array(), cbor_deserialize_array()
* - cbor_serialize_array_indefinite(), cbor_deserialize_array_indefinite(),
* cbor_at_break()
*
* - Major type 5 (map of pairs of data items): Full support. Relevant functions:
* - cbor_serialize_map(), cbor_deserialize_map()
* - cbor_serialize_map_indefinite(), cbor_deserialize_map_indefinite(),
* cbor_at_break()
*
* - Major type 6 (optional semantic tagging of other major types): Basic
* support (see below). Relevant functions:
* - cbor_write_tag()
* - cbor_deserialize_date_time()
* - cbor_serialize_date_time()
*
* - Major type 7 (floating-point numbers and values with no content): Basic
* support (see below). Relevant functions:
* - cbor_serialize_float_half(), cbor_deserialize_float_half()
* - cbor_serialize_float(), cbor_deserialize_float()
* - cbor_serialize_double(), cbor_deserialize_double()
* - cbor_serialize_bool(), cbor_deserialize_bool()
*
* ## Notes about major type 3
* Since we do not have a standardised C type for representing Unicode code
* points, we just provide API to serialize/deserialize `char` arrays. The
* user then has to transform that into a meaningful representation
*
* ## Notes about major type 6
* Encoding date and time: date/time strings that follow the standard format
* described in
* [RFC3339, section 5.6](https://tools.ietf.org/html/rfc3339#section-5.6):
*
* | Date/Time string | Support |
* | ---------------------------: | :------------ |
* | 2003-12-13T18:30:02Z | supported |
* | 2003-12-13T18:30:02.25Z | not supported |
* | 2003-12-13T18:30:02+01:00 | not supported |
* | 2003-12-13T18:30:02.25+01:00 | not supported |
*
* Since we do not have C types for representing
* bignums/bigfloats/decimal-fraction we do not provide API to
* serialize/deserialize them at all. You can still read out the actual data
* item behind the tag (via cbor_deserialize_byte_string()) and interpret it
* yourself.
*
* @see [RFC7049, section 2.4](https://tools.ietf.org/html/rfc7049#section-2.4)
*
* # Notes about major type 7 and simple values
* Simple values:
*
* | Simple value types | Support |
* | :---------------------- | :------------------------------------------------------------- |
* | 0-19: (Unassigned) | not supported |
* | 20,21: True, False | supported (see cbor_serialize_bool(), cbor_deserialize_bool()) |
* | 22,23: Null, Undefined | not supported (what's the use-case?) |
* | 24-31: (Reserved) | not supported |
* | 32-255: (Unassigned) | not supported |
*
* @see [RFC7049, section 2.4](https://tools.ietf.org/html/rfc7049#section-2.3)
*
* @todo API for Indefinite-Length Byte Strings and Text Strings
* (see https://tools.ietf.org/html/rfc7049#section-2.2.2)
* @{
*/
/**
* @file
* @brief CBOR definitions
*
* @author Kevin Funk <kfunk@kde.org>
* @author Jana Cavojska <jana.cavojska9@gmail.com>
* @author Oliver Hahm <oliver.hahm@inria.fr>
*
*/
#ifndef CBOR_H
#define CBOR_H
#include <stdbool.h>
#include <stdint.h>
#include <stdlib.h>
#ifdef MODULE_CBOR_CTIME
#include <time.h>
#endif /* MODULE_CBOR_CTIME */
#ifdef __cplusplus
extern "C" {
#endif
/**
* @brief Struct containing CBOR-encoded data
*
* A typical usage of CBOR looks like:
*
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~ {.c}
* unsigned char data[1024];
* cbor_stream_t stream;
* cbor_init(&stream, data, sizeof(data));
*
* cbor_serialize_int(&stream, 5);
* // (...)
* // <data contains CBOR encoded items now>
*
* cbor_destroy(&stream);
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~
*
* @see cbor_init
* @see cbor_clear
* @see cbor_destroy
*/
typedef struct {
unsigned char *data; /**< Array containing CBOR encoded data */
size_t size; /**< Size of the array */
size_t pos; /**< Index to the next free byte */
} cbor_stream_t;
/**
* @brief Initialize cbor struct
*
* @note Does *not* take ownership of @p buffer
* @param[in] stream The cbor struct to initialize
* @param[in] buffer The buffer used for storing CBOR-encoded data
* @param[in] size The size of buffer @p buffer
*/
void cbor_init(cbor_stream_t *stream, unsigned char *buffer, size_t size);
/**
* @brief Clear cbor struct
*
* Sets pos to zero
*
* @param[in, out] stream Pointer to the cbor struct
*/
void cbor_clear(cbor_stream_t *stream);
/**
* @brief Destroy the cbor struct
*
* @note Does *not* free data
*
* @param[in, out] stream Pointer to the cbor struct
*/
void cbor_destroy(cbor_stream_t *stream);
/**
* @brief Print @p stream in hex representation
*
* @param[in] stream Pointer to the cbor struct
*/
void cbor_stream_print(const cbor_stream_t *stream);
/**
* @brief Decode CBOR from @p stream
*
* This method interprets the data and prints each item in its natural
* representation
*
* Example output:
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ {.c}
* Data:
* (int, 1)
* (bool, 1)
* (float, 1.099609)
* (tag: 0, date/time string: "Mon Jul 14 19:07:40 2014")
* (tag: 1, date/time epoch: 1405357660)
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*
* @param[in] stream Pointer to the cbor struct
*/
void cbor_stream_decode(cbor_stream_t *stream);
/**
* @brief Serializes an integer
*
* @param[out] stream The destination stream for serializing the array
* @param[in] val The integer to serialize
*
* @return Number of bytes written to stream @p stream
*/
size_t cbor_serialize_int(cbor_stream_t *stream, int val);
/**
* @brief Deserialize integers from @p stream to @p val
*
* @param[in] stream The stream to deserialize
* @param[in] offset The offset within the stream where to start deserializing
* @param[out] val Pointer to destination array
*
* @return Number of bytes read from @p stream
*/
size_t cbor_deserialize_int(const cbor_stream_t *stream, size_t offset,
int *val);
/**
* @brief Serializes an unsigned 64 bit value
*
* @param[out] stream The destination stream for serializing the array
* @param[in] val The 64 bit integer to serialize
*
* @return Number of bytes written to stream @p stream
*/
size_t cbor_serialize_uint64_t(cbor_stream_t *stream, uint64_t val);
/**
* @brief Deserialize unsigned 64 bit values from @p stream to @p val
*
* @param[in] stream The stream to deserialize
* @param[in] offset The offset within the stream where to start deserializing
* @param[out] val Pointer to destination array
*
* @return Number of bytes read from @p stream
*/
size_t cbor_deserialize_uint64_t(const cbor_stream_t *stream, size_t offset,
uint64_t *val);
/**
* @brief Serializes a signed 64 bit value
*
* @param[out] stream The destination stream for serializing the array
* @param[in] val The 64 bit integer to serialize
*
* @return Number of bytes written to stream @p stream
*/
size_t cbor_serialize_int64_t(cbor_stream_t *stream, int64_t val);
/**
* @brief Deserialize signed 64 bit values from @p stream to @p val
*
* @param[in] stream The stream to deserialize
* @param[in] offset The offset within the stream where to start deserializing
* @param[out] val Pointer to destination array
*
* @return Number of bytes read from @p stream
*/
size_t cbor_deserialize_int64_t(const cbor_stream_t *stream, size_t offset,
int64_t *val);
/**
* @brief Serializes a boolean value
*
* @param[out] stream The destination stream for serializing the array
* @param[in] val The boolean value to serialize
*
* @return Number of bytes written to stream @p stream
*/
size_t cbor_serialize_bool(cbor_stream_t *stream, bool val);
/**
* @brief Deserialize boolean values from @p stream to @p val
*
* @param[in] stream The stream to deserialize
* @param[in] offset The offset within the stream where to start deserializing
* @param[out] val Pointer to destination array
*
* @return Number of bytes read from @p stream
*/
size_t cbor_deserialize_bool(const cbor_stream_t *stream, size_t offset,
bool *val);
#ifdef MODULE_CBOR_FLOAT
/**
* @brief Serializes a half-width floating point value
*
* @param[out] stream The destination stream for serializing the array
* @param[in] val The half-width floating point value to serialize
*
* @return Number of bytes written to stream @p stream
*/
size_t cbor_serialize_float_half(cbor_stream_t *stream, float val);
/**
* @brief Deserialize half-width floating point values values from @p stream to
* @p val
*
* @param[in] stream The stream to deserialize
* @param[in] offset The offset within the stream where to start deserializing
* @param[out] val Pointer to destination array
*
* @return Number of bytes read from @p stream
*/
size_t cbor_deserialize_float_half(const cbor_stream_t *stream, size_t offset,
float *val);
/**
* @brief Serializes a floating point value
*
* @param[out] stream The destination stream for serializing the array
* @param[in] val The float to serialize
*
* @return Number of bytes written to stream @p stream
*/
size_t cbor_serialize_float(cbor_stream_t *stream, float val);
/**
* @brief Deserialize floating point values values from @p stream to @p val
*
* @param[in] stream The stream to deserialize
* @param[in] offset The offset within the stream where to start deserializing
* @param[out] val Pointer to destination array
*
* @return Number of bytes read from @p stream
*/
size_t cbor_deserialize_float(const cbor_stream_t *stream, size_t offset,
float *val);
/**
* @brief Serializes a double precision floating point value
*
* @param[out] stream The destination stream for serializing the array
* @param[in] val The double to serialize
*
* @return Number of bytes written to stream @p stream
*/
size_t cbor_serialize_double(cbor_stream_t *stream, double val);
/**
* @brief Deserialize double precision floating point valeus from @p stream to
* @p val
*
* @param[in] stream The stream to deserialize
* @param[in] offset The offset within the stream where to start deserializing
* @param[out] val Pointer to destination array
*
* @return Number of bytes read from @p stream
*/
size_t cbor_deserialize_double(const cbor_stream_t *stream, size_t offset,
double *val);
#endif /* MODULE_CBOR_FLOAT */
/**
* @brief Serializes a signed 64 bit value
*
* @param[out] stream The destination stream for serializing the array
* @param[in] val The 64 bit integer to serialize
*
* @return Number of bytes written to stream @p stream
*/
size_t cbor_serialize_byte_string(cbor_stream_t *stream, const char *val);
/**
* @brief Serializes an arbitrary byte string
*
* @param[out] stream The destination stream for serializing the byte stream
* @param[in] val The arbitrary byte string which may include null bytes
* @param[in] length The size of the byte string in bytes
*
* @return Number of bytes written to stream @p stream
*/
size_t cbor_serialize_byte_stringl(cbor_stream_t *stream, const char *val, size_t length);
/**
* @brief Deserialize bytes from @p stream to @p val
*
* @param[in] stream The stream to deserialize
* @param[in] offset The offset within the stream where to start deserializing
* @param[out] val Pointer to destination array
* @param[in] length Length of destination array
*
* @return Number of bytes read from @p stream
*/
size_t cbor_deserialize_byte_string(const cbor_stream_t *stream, size_t offset,
char *val, size_t length);
/**
* @brief Serializes a unicode string.
*
* @param[out] stream The destination stream for serializing the unicode
* string
* @param[out] val The zero-terminated unicode string to serialize.
*
* @return Number of bytes written to stream @p stream
*/
size_t cbor_serialize_unicode_string(cbor_stream_t *stream, const char *val);
/**
* @brief Deserialize bytes from @p stream to @p val (without copy)
*
* @param[in] stream The stream to deserialize
* @param[in] offset The offset within the stream where to start deserializing
* @param[out] val Pointer to a char *
* @param[out] length Pointer to a size_t to store the size of the string
*
* @return Number of bytes written into @p val
*/
size_t cbor_deserialize_byte_string_no_copy(const cbor_stream_t *stream, size_t offset,
unsigned char **val, size_t *length);
/**
* @brief Deserialize unicode string from @p stream to @p val (without copy)
*
* @param[in] stream The stream to deserialize
* @param[in] offset The offset within the stream where to start deserializing
* @param[out] val Pointer to a char *
* @param[out] length Pointer to a size_t to store the size of the string
*
* @return Number of bytes written into @p val
*/
size_t cbor_deserialize_unicode_string_no_copy(const cbor_stream_t *stream, size_t offset,
unsigned char **val, size_t *length);
/**
* @brief Deserialize unicode string from @p stream to @p val
*
* @param[in] stream The stream to deserialize
* @param[in] offset The offset within the stream where to start deserializing
* @param[out] val Pointer to destination array
* @param[in] length Length of destination array
*
* @return Number of bytes read from @p stream
*/
size_t cbor_deserialize_unicode_string(const cbor_stream_t *stream,
size_t offset, char *val, size_t length);
/**
* @brief Serialize array of length @p array_length
*
* Basic usage:
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ {.c}
* cbor_serialize_array(&stream, 2); // array of length 2 follows
* cbor_serialize_int(&stream, 1)); // write item 1
* cbor_serialize_int(&stream, 2)); // write item 2
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*
* @note You have to make sure to serialize the correct amount of items.
* If you exceed the length @p array_length, items will just be appened as normal
*
* @param[out] stream The destination stream for serializing the array
* @param[in] array_length Length of the array of items which follows
*
* @return Number of bytes written to stream @p stream
*/
size_t cbor_serialize_array(cbor_stream_t *stream, size_t array_length);
/**
* @brief Deserialize array of items
*
* Basic usage:
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~ {.c}
* size_t array_length;
* // read out length of the array
* size_t offset = cbor_deserialize_array(&stream, 0, &array_length);
* int i1, i2;
* offset += cbor_deserialize_int(&stream, offset, &i1); // read item 1
* offset += cbor_deserialize_int(&stream, offset, &i2); // read item 2
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~
*
* @param[in] stream The stream to deserialize
* @param[in] offset The offset within the stream
* @param[in] array_length Where the array length is stored
*
* @return Number of deserialized bytes from stream
*/
size_t cbor_deserialize_array(const cbor_stream_t *stream, size_t offset,
size_t *array_length);
/**
* @brief Serialize array of infite length
*
* @param[out] stream The destination stream for serializing the array
*
* @return Number of bytes written to stream @p stream
*/
size_t cbor_serialize_array_indefinite(cbor_stream_t *stream);
/**
* @brief Deserialize array of items
*
* @param[in] stream The stream to deserialize
* @param[in] offset The offset within the stream
*
* @return Number of deserialized bytes from stream
*/
size_t cbor_deserialize_array_indefinite(const cbor_stream_t *stream, size_t offset);
/**
* @brief Serialize map of length @p map_length
*
* Basic usage:
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ {.c}
* cbor_serialize_map(&stream, 2); // map of length 2 follows
* cbor_serialize_int(&stream, 1)); // write key 1
* cbor_serialize_byte_string(&stream, "1")); // write value 1
* cbor_serialize_int(&stream, 2)); // write key 2
* cbor_serialize_byte_string(&stream, "2")); // write value 2
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*
* @param[out] stream The destination stream for serializing the map
* @param map_length Length of the map of items which follows
*
* @return Number of bytes written to stream @p stream
*/
size_t cbor_serialize_map(cbor_stream_t *stream, size_t map_length);
/**
* @brief Deserialize map of items
*
* Basic usage:
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ {.c}
* size_t map_length;
* // read out length of the map
* size_t offset = cbor_deserialize_map(&stream, 0, &map_length);
* int key1, key1;
* char value1[8], value2[8];
* // read key 1
* offset += cbor_deserialize_int(&stream, offset, &key1);
* // read value 1
* offset += cbor_deserialize_byte_string(&stream, offset, value1, sizeof(value));
* // read key 2
* offset += cbor_deserialize_int(&stream, offset, &key2);
* // read value 2
* offset += cbor_deserialize_byte_string(&stream, offset, value2, sizeof(value));
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*
* @param[in] stream The stream to deserialize
* @param[in] offset The offset within the stream where to start deserializing
* @param[in] map_length Where the array length is stored
*
* @return Number of deserialized bytes from @p stream
*/
size_t cbor_deserialize_map(const cbor_stream_t *stream, size_t offset,
size_t *map_length);
/**
* @brief Serialize map of infite length
*
* @param[out] stream The destination stream for serializing the map
*
* @return Number of bytes written to stream @p stream
*/
size_t cbor_serialize_map_indefinite(cbor_stream_t *stream);
/**
* @brief Deserialize map of items
*
* @param[in] stream The stream to deserialize
* @param[in] offset The offset within the stream
*
* @return Number of deserialized bytes from stream
*/
size_t cbor_deserialize_map_indefinite(const cbor_stream_t *stream, size_t offset);
#ifdef MODULE_CBOR_SEMANTIC_TAGGING
#ifdef MODULE_CBOR_CTIME
/**
* @brief Serialize date and time
*
* Basic usage:
* ~~~~~~~~~~~~~~~~~~~~~~~~ {.c}
* struct tm val;
* val.tm_year = 114;
* val.tm_mon = 6;
* val.tm_mday = 1;
* val.tm_hour = 15;
* val.tm_min = 0;
* val.tm_sec = 0;
* mktime(&val);
* cbor_serialize_date_time(&stream, &val);
* ~~~~~~~~~~~~~~~~~~~~~~~~
*
* @param[out] stream The destination stream for serializing the date_time
* @param[in] val tm struct containing the date/time info to be encoded
*
* @return Number of bytes written to stream @p stream
*/
size_t cbor_serialize_date_time(cbor_stream_t *stream, struct tm *val);
/**
* @brief Deserialize date and time
*
* Basic usage:
* ~~~~~~~~~~~~~~~~~~~~~~~~ {.c}
* struct tm val;
* cbor_deserialize_date_time(&stream, 0, &val);
* ~~~~~~~~~~~~~~~~~~~~~~~~
*
* @param[in] stream The stream to deserialize
* @param[in] offset The offset within the stream where to start deserializing
* @param[out] val tm struct where the decoded date/time will be stored
*
* @return The number of deserialized bytes
*/
size_t cbor_deserialize_date_time(const cbor_stream_t *stream, size_t offset, struct tm *val);
/**
* @brief Serialize seconds since UNIX epoch
*
* @param[out] stream The destination stream for serializing the date_time
* @param[in] val Time in seconds since UNIX epoch
*
* @return Number of bytes written to stream @p stream
*/
size_t cbor_serialize_date_time_epoch(cbor_stream_t *stream, time_t val);
/**
* @brief Deserialize seconds since UNIX epoch
*
* @param[in] stream The stream to deserialize
* @param[in] offset The offset within the stream where to start deserializing
* @param[out] val `time_t` variable where the decoded date/time will be stored
*
* @return The number of deserialized bytes
*/
size_t cbor_deserialize_date_time_epoch(const cbor_stream_t *stream, size_t offset, time_t *val);
#endif /* MODULE_CBOR_CTIME */
/**
* @brief Write a tag to give the next CBOR item additional semantics
*
* Also see https://tools.ietf.org/html/rfc7049#section-2.4 (Optional Tagging of Items)
*
* @param[in, out] stream Pointer to the cbor struct
* @param[in] tag The tag to write
*
* @return Always 1
*/
size_t cbor_write_tag(cbor_stream_t *stream, unsigned char tag);
/**
* @brief Whether we are at a tag symbol in stream @p stream at offset @p offset
*
* @param[in] stream Pointer to the cbor struct
* @param[in] offset The offset within @p stream
*
* @return True in case there is a tag symbol at the current offset
*/
bool cbor_at_tag(const cbor_stream_t *stream, size_t offset);
#endif /* MODULE_CBOR_SEMANTIC_TAGGING */
/**
* @brief Write a break symbol at the current offset in stream @p stream
*
* Used for marking the end of indefinite length CBOR items
*
* @param[in] stream Pointer to the cbor struct
*
* @return Always 1
*/
size_t cbor_write_break(cbor_stream_t *stream);
/**
* @brief Whether we are at a break symbol in stream @p stream at offset @p offset
*
* @param[in] stream Pointer to the cbor struct
* @param[in] offset The offset within @p stream
*
* @return True in case the there is a break symbol at the current offset
*/
bool cbor_at_break(const cbor_stream_t *stream, size_t offset);
/**
* @brief Whether we are at the end of the stream @p stream at offset @p offset
*
* Useful for abort conditions in loops while deserializing CBOR items
*
* @param[in] stream Pointer to the cbor struct
* @param[in] offset The offset within @p stream
*
* @return True in case @p offset marks the end of the stream
*/
bool cbor_at_end(const cbor_stream_t *stream, size_t offset);
#ifdef __cplusplus
}
#endif
#endif /* CBOR_H */
/** @} */