Detailed Description

A FieldDescriptor that consists of a group of FieldDescriptors. Groups can vary in size two ways. First, the group may contain a field which itself is of variable size (i.e. a string or another group). This type of message structure requires some other data in the message itself to indicate the field/group length and as such isn't supported.

An example of this type of group would be:

* +----------------+
* |    bool (1)    |
* +----------------+
* | string (0, 32) |
* +----------------+
*

This could hold data like: (true, "foo"), (false, "bar)

The second (and simpler) type is where the group size is fixed (i.e. contains only fixed length fields) and the number of times the group appears in the message varies. By knowing the length of the message we can work out the number of times a group occurs (see VariableFieldSizeCalculator.h which does this).

An example of this type of group would be:

* +----------------+
* |    bool (1)    |
* +----------------+
* |   uint16 (2)   |
* +----------------+
*

This could hold data like: (true, 1000), (false, 34)

DescriptorConsistencyChecker.h checks that a descriptor is the second type, that is contains at most one variable-sized field.

We refer to the datatypes within a group as fields, the actual instantiations of a group as blocks. In the examples above, bool, string and uint16 are the fields (represented by FieldDescriptorInterface objects) and (true, "foo") & (true, 1000) are the blocks.

Inheritance diagram for ola::messaging::FieldDescriptorGroup:

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Collaboration diagram for ola::messaging::FieldDescriptorGroup:

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Public Member Functions
	FieldDescriptorGroup (const std::string &name, const std::vector< const FieldDescriptor *> &fields, uint16_t min_blocks, int16_t max_blocks)

bool	FixedSize () const

bool	LimitedSize () const

unsigned int	MaxSize () const

unsigned int	FieldCount () const

bool	FixedBlockSize () const

unsigned int	BlockSize () const

unsigned int	MaxBlockSize () const

uint16_t	MinBlocks () const

int16_t	MaxBlocks () const

bool	FixedBlockCount () const

const class FieldDescriptor *	GetField (unsigned int index) const

virtual void	Accept (FieldDescriptorVisitor *visitor) const

Public Member Functions inherited from ola::messaging::FieldDescriptor
	FieldDescriptor (const std::string &name)

const std::string &	Name () const

Static Public Attributes
static const int16_t	UNLIMITED_BLOCKS = -1

Protected Attributes
std::vector< const class FieldDescriptor * >	m_fields

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

include/ola/messaging/Descriptor.h
common/messaging/Descriptor.cpp

Detailed Description

Public Member Functions

Static Public Attributes

Protected Attributes