gr_unpacked_to_packed_bb Class Reference

Convert a stream of unpacked bytes or shorts into a stream of packed bytes or shorts.input: stream of unsigned char; output: stream of unsigned char. More...

#include <gr_unpacked_to_packed_bb.h>

Inheritance diagram for gr_unpacked_to_packed_bb:

List of all members.

Public Member Functions
void	forecast (int noutput_items, gr_vector_int &ninput_items_required)
	Estimate input requirements given output request.
int	general_work (int noutput_items, gr_vector_int &ninput_items, gr_vector_const_void_star &input_items, gr_vector_void_star &output_items)
	compute output items from input items
bool	check_topology (int ninputs, int noutputs)
	Confirm that ninputs and noutputs is an acceptable combination.
Friends
GR_CORE_API gr_unpacked_to_packed_bb_sptr	gr_make_unpacked_to_packed_bb (unsigned int bits_per_chunk, gr_endianness_t endianness)

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Detailed Description

Convert a stream of unpacked bytes or shorts into a stream of packed bytes or shorts.

input: stream of unsigned char; output: stream of unsigned char.

This is the inverse of gr_packed_to_unpacked_XX.

The low bits_per_chunk bits are extracted from each input byte or short. These bits are then packed densely into the output bytes or shorts, such that all 8 or 16 bits of the output bytes or shorts are filled with valid input bits. The right thing is done if bits_per_chunk is not a power of two.

The combination of gr_packed_to_unpacked_XX followed by gr_chunks_to_symbols_Xf or gr_chunks_to_symbols_Xc handles the general case of mapping from a stream of bytes or shorts into arbitrary float or complex symbols.

See also:

gr_packed_to_unpacked_bb, gr_unpacked_to_packed_bb,

gr_packed_to_unpacked_ss, gr_unpacked_to_packed_ss,

gr_chunks_to_symbols_bf, gr_chunks_to_symbols_bc.

gr_chunks_to_symbols_sf, gr_chunks_to_symbols_sc.

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Member Function Documentation

bool gr_unpacked_to_packed_bb::check_topology	(	int	ninputs,
		int	noutputs
	)		[inline, virtual]

Confirm that ninputs and noutputs is an acceptable combination.

Parameters:

ninputs	number of input streams connected
noutputs	number of output streams connected

Returns:

true if this is a valid configuration for this block.

This function is called by the runtime system whenever the topology changes. Most classes do not need to override this. This check is in addition to the constraints specified by the input and output gr_io_signatures.

Reimplemented from gr_basic_block.

void gr_unpacked_to_packed_bb::forecast	(	int	noutput_items,
		gr_vector_int &	ninput_items_required
	)		[virtual]

Estimate input requirements given output request.

Parameters:

noutput_items	number of output items to produce
ninput_items_required	number of input items required on each input stream

Given a request to product noutput_items, estimate the number of data items required on each input stream. The estimate doesn't have to be exact, but should be close.

Reimplemented from gr_block.

int gr_unpacked_to_packed_bb::general_work	(	int	noutput_items,
		gr_vector_int &	ninput_items,
		gr_vector_const_void_star &	input_items,
		gr_vector_void_star &	output_items
	)		[virtual]

compute output items from input items

Parameters:

noutput_items	number of output items to write on each output stream
ninput_items	number of input items available on each input stream
input_items	vector of pointers to the input items, one entry per input stream
output_items	vector of pointers to the output items, one entry per output stream

Returns:

number of items actually written to each output stream, or -1 on EOF. It is OK to return a value less than noutput_items. -1 <= return value <= noutput_items

general_work must call consume or consume_each to indicate how many items were consumed on each input stream.

Reimplemented from gr_block.

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Friends And Related Function Documentation

GR_CORE_API gr_unpacked_to_packed_bb_sptr gr_make_unpacked_to_packed_bb	(	unsigned int	bits_per_chunk,
		gr_endianness_t	endianness
	)		[friend]

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

• gr_unpacked_to_packed_bb.h