Detailed Description

Creates an ephemeral reader for the Concise Binary Object Representation (CBOR, IETF RFC8949), holding underlying objects and providing more concise member functions.

This reader wraps the QCBOR library into a more familiar interface that performs stack buffer allocation and io::Readable handling automatically. QCBOR decode requires a working buffer to hold the in-progress object, which should be allocated by a child class, typically cbor::ListReaderStatic or cbor::MapReaderStatic.

Most users should be able to hit target functionality with usage of cbor::ListReader cbor::MapReader or other future wrappers. However, the QCBOR decode context cbor is a public member variable that may be used for calls to QCBORDecode_* functions for complex use-cases outside the scope of provided wrapper classes.

Usage:

Create a CborReader object, which copies from any io::Readable sink and calls read_finalize(). If no io::Readable is passed, the given buffer is assumed to be populated with a CBOR payload.
Use member functions of a child class such as cbor::ListReader or cbor::MapReader to read a valid CBOR list or map, respectively.
For any edge cases, use QCBORDecode_* functions with the given QCBOR context cbor.

Most users should instantiate ListReaderStatic or MapReaderStatic instead of this to perform all stack buffer allocation.

See also: satcat5::cbor::ListReader, satcat5::cbor::MapReader

Definition at line 465 of file io_cbor.h.

#include <io_cbor.h>

Inheritance diagram for satcat5::cbor::CborReader:

[legend]

Public Member Functions
bool	ok () const
	Check if any errors have been encountered yet during decoding.

QCBORError	get_error () const
	Get the QCBOR decoding error, if any.

void	close_list () const
	Resume parsing at the end of a nested list. More...

void	close_map () const
	Resume parsing at the end of a nested dictionary. More...

bool	copy_item (QCBOREncodeContext *dst)
	Copy the next CBOR item to the specified destination. More...

unsigned	copy_all (QCBOREncodeContext *dst)
	Copy all remaining CBOR item(s) to the specified destination. More...

Public Attributes
QCBORDecodeContext *const	cbor
	QCBOR context pointer.

Static Public Attributes
static const int	ERR_NOT_FOUND = -1
	Key not found.

static const int	ERR_OVERFLOW = -2
	Overflowed user array.

static const int	ERR_BAD_TYPE = -3
	Non-matching type.

static const int	ERR_QCBOR_INT = -4
	Misc QCBOR error.

Protected Member Functions
	CborReader (satcat5::io::Readable src, QCBORDecodeContext decode, u8 *buff, unsigned size)
	Opens a QCBOR Decode Context from an io::Readable. More...

constexpr	CborReader (QCBORDecodeContext *decode)
	Create a CborReader from an existing decoder context.

	CborReader (const CborReader &other)=delete

CborReader &	operator= (const CborReader &other)=delete

int	get_array_internal (satcat5::io::Writeable &dst, u8 qcbor_type, u8 type_size) const
	Internal function for shared array logic. More...

unsigned	peek_integer_len (const u8 *rdptr) const
	Predict the length of the next integer value. More...

Protected Attributes
QCBORItem	m_item
	QCBOR Decoder item.

Constructor & Destructor Documentation

◆ CborReader()

satcat5::cbor::CborReader::CborReader	(	satcat5::io::Readable *	src,
		QCBORDecodeContext *	decode,
		u8 *	buff,
		unsigned	size
	)

protected

Opens a QCBOR Decode Context from an io::Readable.

Constructor requires child class to provide a working buffer.

Parameters

src	Readable source to decode, or NULL if buffers are already populated.
decode	Pointer to an uninitialized QCBOR encoder object.
buff	Backing buffer for QCBOR.
size	Backing buffer size for QCBOR.

Definition at line 179 of file io_cbor.cc.

Member Function Documentation

◆ close_list()

void satcat5::cbor::CborReader::close_list ( ) const

inline

Resume parsing at the end of a nested list.

See also: ListReader::open_list, MapReader::open_list.

Definition at line 477 of file io_cbor.h.

◆ close_map()

void satcat5::cbor::CborReader::close_map ( ) const

inline

Resume parsing at the end of a nested dictionary.

See also: ListReader::open_map, MapReader::open_map.

Definition at line 482 of file io_cbor.h.

◆ copy_all()

unsigned satcat5::cbor::CborReader::copy_all ( QCBOREncodeContext * dst )

Copy all remaining CBOR item(s) to the specified destination.

Returns: The number of items copied.

Definition at line 227 of file io_cbor.cc.

◆ copy_item()

bool satcat5::cbor::CborReader::copy_item ( QCBOREncodeContext * dst )

Copy the next CBOR item to the specified destination.

If the next item is a nested data structure, this copies the entire data structure to the destination object.

Returns: True if an item was copied successfully.

Definition at line 194 of file io_cbor.cc.

◆ get_array_internal()

int satcat5::cbor::CborReader::get_array_internal	(	satcat5::io::Writeable &	dst,
		u8	qcbor_type,
		u8	type_size
	)		const

protected

Internal function for shared array logic.

This function is called by all other "get_array" variants.

Definition at line 520 of file io_cbor.cc.

◆ peek_integer_len()

unsigned satcat5::cbor::CborReader::peek_integer_len ( const u8 * rdptr ) const

protected

Predict the length of the next integer value.

Standard integers may be 1, 2, 3, 5, or 9 bytes.

Returns: Length in bytes, or zero on error.

Definition at line 237 of file io_cbor.cc.

The documentation for this class was generated from the following files:

Detailed Description

Public Member Functions

Public Attributes

Static Public Attributes

Protected Member Functions

Protected Attributes

Constructor & Destructor Documentation

◆ CborReader()

Member Function Documentation

◆ close_list()

◆ close_map()

◆ copy_all()

◆ copy_item()

◆ get_array_internal()

◆ peek_integer_len()