GNU Radio 3.6.0 C++ API
gr_block Class Reference

The abstract base class for all 'terminal' processing blocks.A signal processing flow is constructed by creating a tree of hierarchical blocks, which at any level may also contain terminal nodes that actually implement signal processing functions. This is the base class for all such leaf nodes. More...

#include <gr_block.h>

Inheritance diagram for gr_block:
gr_basic_block gr_msg_accepter gruel::msg_accepter atsc_bit_timing_loop atsc_field_sync_demux block_gateway digital_clock_recovery_mm_cc digital_clock_recovery_mm_ff digital_constellation_decoder_cb digital_constellation_receiver_cb digital_mpsk_receiver_cc digital_ofdm_frame_acquisition digital_ofdm_insert_preamble digital_ofdm_sampler gnuradio::extras::delay gr_align_on_samplenumbers_ss gr_block_gateway gr_copy gr_delay gr_fractional_interpolator_cc gr_fractional_interpolator_ff gr_keep_one_in_n gr_nop gr_ofdm_bpsk_demapper gr_pfb_arb_resampler_ccf gr_pfb_arb_resampler_fff gr_pfb_channelizer_ccf gr_pfb_clock_sync_ccf gr_pfb_clock_sync_fff gr_simple_correlator gr_simple_framer gr_skiphead gr_squelch_base_cc gr_squelch_base_ff gr_stream_mux gr_sync_block gr_test howto_square_ff noaa_hrpt_deframer pager_flex_sync qtgui_sink_c qtgui_sink_f trellis_constellation_metrics_cf trellis_siso_combined_f trellis_siso_f

List of all members.

Public Types

enum  { WORK_CALLED_PRODUCE = -2, WORK_DONE = -1 }
 Magic return values from general_work. More...
enum  tag_propagation_policy_t { TPP_DONT = 0, TPP_ALL_TO_ALL = 1, TPP_ONE_TO_ONE = 2 }

Public Member Functions

virtual ~gr_block ()
unsigned history () const
void set_history (unsigned history)
bool fixed_rate () const
 Return true if this block has a fixed input to output rate.
virtual void forecast (int noutput_items, gr_vector_int &ninput_items_required)
 Estimate input requirements given output request.
virtual int general_work (int noutput_items, gr_vector_int &ninput_items, gr_vector_const_void_star &input_items, gr_vector_void_star &output_items)=0
 compute output items from input items
virtual bool start ()
 Called to enable drivers, etc for i/o devices.
virtual bool stop ()
 Called to disable drivers, etc for i/o devices.
void set_output_multiple (int multiple)
 Constrain the noutput_items argument passed to forecast and general_work.
int output_multiple () const
bool output_multiple_set () const
void set_alignment (int multiple)
 Constrains buffers to work on a set item alignment (for SIMD)
int alignment () const
void set_unaligned (int na)
int unaligned () const
void set_is_unaligned (bool u)
bool is_unaligned () const
void consume (int which_input, int how_many_items)
 Tell the scheduler how_many_items of input stream which_input were consumed.
void consume_each (int how_many_items)
 Tell the scheduler how_many_items were consumed on each input stream.
void produce (int which_output, int how_many_items)
 Tell the scheduler how_many_items were produced on output stream which_output.
void set_relative_rate (double relative_rate)
 Set the approximate output rate / input rate.
double relative_rate () const
 return the approximate output rate / input rate
virtual int fixed_rate_ninput_to_noutput (int ninput)
 Given ninput samples, return number of output samples that will be produced. N.B. this is only defined if fixed_rate returns true. Generally speaking, you don't need to override this.
virtual int fixed_rate_noutput_to_ninput (int noutput)
 Given noutput samples, return number of input samples required to produce noutput. N.B. this is only defined if fixed_rate returns true. Generally speaking, you don't need to override this.
uint64_t nitems_read (unsigned int which_input)
 Return the number of items read on input stream which_input.
uint64_t nitems_written (unsigned int which_output)
 Return the number of items written on output stream which_output.
tag_propagation_policy_t tag_propagation_policy ()
 Asks for the policy used by the scheduler to moved tags downstream.
void set_tag_propagation_policy (tag_propagation_policy_t p)
 Set the policy by the scheduler to determine how tags are moved downstream.
gr_block_detail_sptr detail () const
void set_detail (gr_block_detail_sptr detail)

Protected Member Functions

 gr_block (void)
 gr_block (const std::string &name, gr_io_signature_sptr input_signature, gr_io_signature_sptr output_signature)
void set_fixed_rate (bool fixed_rate)
void add_item_tag (unsigned int which_output, uint64_t abs_offset, const pmt::pmt_t &key, const pmt::pmt_t &value, const pmt::pmt_t &srcid=pmt::PMT_F)
 Adds a new tag onto the given output buffer.
void add_item_tag (unsigned int which_output, const gr_tag_t &tag)
 Adds a new tag onto the given output buffer.
void get_tags_in_range (std::vector< gr_tag_t > &v, unsigned int which_input, uint64_t abs_start, uint64_t abs_end)
 Given a [start,end), returns a vector of all tags in the range.
void get_tags_in_range (std::vector< gr_tag_t > &v, unsigned int which_input, uint64_t abs_start, uint64_t abs_end, const pmt::pmt_t &key)
 Given a [start,end), returns a vector of all tags in the range with a given key.
void push_msg_queue (const gr_tag_t &msg)
 Enqueue a message into this block. Usually this is called internally. However, it may be useful for the block itself or an outside entity to post messages to the block. Ex: Push can be used to wake up a thread blocking on pop_msg_queue.
bool check_msg_queue (void)
 Check if a message is available to pop.
gr_tag_t pop_msg_queue (void)
 Pop a message from the front of the queue. This function will block until a message is available.
void post_msg (const std::string &group, const gr_tag_t &msg)
 Post a message to a subscriber group. All message subscribers in the group will get this message.
void post_msg (const std::string &group, const pmt::pmt_t &key, const pmt::pmt_t &value, const pmt::pmt_t &srcid=pmt::PMT_F)
 Post a message to a subscriber group.

Friends

class gr_tpb_thread_body

Detailed Description

The abstract base class for all 'terminal' processing blocks.

A signal processing flow is constructed by creating a tree of hierarchical blocks, which at any level may also contain terminal nodes that actually implement signal processing functions. This is the base class for all such leaf nodes.

Blocks have a set of input streams and output streams. The input_signature and output_signature define the number of input streams and output streams respectively, and the type of the data items in each stream.

Although blocks may consume data on each input stream at a different rate, all outputs streams must produce data at the same rate. That rate may be different from any of the input rates.

User derived blocks override two methods, forecast and general_work, to implement their signal processing behavior. forecast is called by the system scheduler to determine how many items are required on each input stream in order to produce a given number of output items.

general_work is called to perform the signal processing in the block. It reads the input items and writes the output items.


Member Enumeration Documentation

anonymous enum

Magic return values from general_work.

Enumerator:
WORK_CALLED_PRODUCE 
WORK_DONE 
Enumerator:
TPP_DONT 
TPP_ALL_TO_ALL 
TPP_ONE_TO_ONE 

Constructor & Destructor Documentation

virtual gr_block::~gr_block ( ) [virtual]
gr_block::gr_block ( void  ) [inline, protected]
gr_block::gr_block ( const std::string name,
gr_io_signature_sptr  input_signature,
gr_io_signature_sptr  output_signature 
) [protected]

Member Function Documentation

void gr_block::add_item_tag ( unsigned int  which_output,
uint64_t  abs_offset,
const pmt::pmt_t key,
const pmt::pmt_t value,
const pmt::pmt_t srcid = pmt::PMT_F 
) [inline, protected]

Adds a new tag onto the given output buffer.

Parameters:
which_outputan integer of which output stream to attach the tag
abs_offseta uint64 number of the absolute item number assicated with the tag. Can get from nitems_written.
keythe tag key as a PMT symbol
valueany PMT holding any value for the given key
srcidoptional source ID specifier; defaults to PMT_F

References gr_tag_t::offset, gr_tag_t::key, gr_tag_t::value, and gr_tag_t::srcid.

Referenced by gr_block_gateway::gr_block__add_item_tag(), block_gateway::gr_block__add_item_tag(), tag_source_demo::make_time_tag(), tag_source_demo::make_sob_tag(), and tag_source_demo::make_eob_tag().

void gr_block::add_item_tag ( unsigned int  which_output,
const gr_tag_t tag 
) [protected]

Adds a new tag onto the given output buffer.

Parameters:
which_outputan integer of which output stream to attach the tag
tagthe tag object to add
int gr_block::alignment ( ) const [inline]
bool gr_block::check_msg_queue ( void  ) [protected]

Check if a message is available to pop.

Returns:
true is a message is in the queue

Referenced by gr_block_gateway::gr_block__check_msg_queue(), and block_gateway::gr_block__check_msg_queue().

void gr_block::consume ( int  which_input,
int  how_many_items 
)

Tell the scheduler how_many_items of input stream which_input were consumed.

Referenced by gr_block_gateway::gr_block__consume(), and block_gateway::gr_block__consume().

void gr_block::consume_each ( int  how_many_items)

Tell the scheduler how_many_items were consumed on each input stream.

Referenced by gr_block_gateway::gr_block__consume_each(), and block_gateway::gr_block__consume_each().

gr_block_detail_sptr gr_block::detail ( ) const [inline]
bool gr_block::fixed_rate ( ) const [inline]

Return true if this block has a fixed input to output rate.

If true, then fixed_rate_in_to_out and fixed_rate_out_to_in may be called.

Referenced by gr_block_gateway::gr_block__fixed_rate(), and block_gateway::gr_block__fixed_rate().

virtual int gr_block::fixed_rate_ninput_to_noutput ( int  ninput) [virtual]

Given ninput samples, return number of output samples that will be produced. N.B. this is only defined if fixed_rate returns true. Generally speaking, you don't need to override this.

Reimplemented in gr_test, gr_sync_interpolator, gr_sync_decimator, and gr_sync_block.

virtual int gr_block::fixed_rate_noutput_to_ninput ( int  noutput) [virtual]

Given noutput samples, return number of input samples required to produce noutput. N.B. this is only defined if fixed_rate returns true. Generally speaking, you don't need to override this.

Reimplemented in gr_test, gr_sync_interpolator, gr_sync_decimator, and gr_sync_block.

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

Estimate input requirements given output request.

Parameters:
noutput_itemsnumber of output items to produce
ninput_items_requirednumber 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 in trellis_siso_combined_f, pager_flex_sync, trellis_siso_f, digital_mpsk_receiver_cc, gr_align_on_samplenumbers_ss, gr_stream_mux, gr_test, digital_clock_recovery_mm_cc, digital_ofdm_sampler, atsc_bit_timing_loop, digital_constellation_decoder_cb, gr_sync_interpolator, digital_clock_recovery_mm_ff, gr_sync_block, gr_sync_decimator, gr_simple_framer, atsc_equalizer, atsc_field_sync_demux, atsc_field_sync_mux, atsc_pad, gr_fractional_interpolator_cc, gr_fractional_interpolator_ff, and trellis_constellation_metrics_cf.

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

compute output items from input items

Parameters:
noutput_itemsnumber of output items to write on each output stream
ninput_itemsnumber of input items available on each input stream
input_itemsvector of pointers to the input items, one entry per input stream
output_itemsvector 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.

Implemented in gr_pfb_clock_sync_ccf, gr_pfb_clock_sync_fff, gr_pfb_channelizer_ccf, gr_pfb_arb_resampler_ccf, gr_pfb_arb_resampler_fff, qtgui_sink_c, qtgui_sink_f, digital_ofdm_frame_acquisition, trellis_siso_combined_f, gr_simple_correlator, digital_ofdm_insert_preamble, pager_flex_sync, trellis_siso_f, digital_mpsk_receiver_cc, gr_align_on_samplenumbers_ss, gr_stream_mux, digital_constellation_receiver_cb, howto_square_ff, gr_ofdm_bpsk_demapper, digital_clock_recovery_mm_cc, digital_ofdm_sampler, atsc_bit_timing_loop, gr_test, digital_constellation_decoder_cb, gr_sync_interpolator, digital_clock_recovery_mm_ff, gr_copy, gr_sync_block, gr_sync_decimator, gr_delay, gr_skiphead, gr_keep_one_in_n, gr_squelch_base_cc, gr_squelch_base_ff, gr_nop, gr_simple_framer, noaa_hrpt_deframer, atsc_field_sync_demux, gr_fractional_interpolator_cc, gr_fractional_interpolator_ff, and trellis_constellation_metrics_cf.

void gr_block::get_tags_in_range ( std::vector< gr_tag_t > &  v,
unsigned int  which_input,
uint64_t  abs_start,
uint64_t  abs_end 
) [protected]

Given a [start,end), returns a vector of all tags in the range.

Range of counts is from start to end-1.

Tags are tuples of: (item count, source id, key, value)

Parameters:
va vector reference to return tags into
which_inputan integer of which input stream to pull from
abs_starta uint64 count of the start of the range of interest
abs_enda uint64 count of the end of the range of interest

Referenced by gr_block_gateway::gr_block__get_tags_in_range(), block_gateway::gr_block__get_tags_in_range(), and tag_sink_demo::work().

void gr_block::get_tags_in_range ( std::vector< gr_tag_t > &  v,
unsigned int  which_input,
uint64_t  abs_start,
uint64_t  abs_end,
const pmt::pmt_t key 
) [protected]

Given a [start,end), returns a vector of all tags in the range with a given key.

Range of counts is from start to end-1.

Tags are tuples of: (item count, source id, key, value)

Parameters:
va vector reference to return tags into
which_inputan integer of which input stream to pull from
abs_starta uint64 count of the start of the range of interest
abs_enda uint64 count of the end of the range of interest
keya PMT symbol key to filter only tags of this key
unsigned gr_block::history ( ) const [inline]

Assume block computes y_i = f(x_i, x_i-1, x_i-2, x_i-3...) History is the number of x_i's that are examined to produce one y_i. This comes in handy for FIR filters, where we use history to ensure that our input contains the appropriate "history" for the filter. History should be equal to the number of filter taps.

Referenced by gr_block_gateway::gr_block__history(), block_gateway::gr_block__history(), gr_delay::delay(), and gr_test::forecast().

bool gr_block::is_unaligned ( ) const [inline]
uint64_t gr_block::nitems_read ( unsigned int  which_input)

Return the number of items read on input stream which_input.

Referenced by gr_block_gateway::gr_block__nitems_read(), block_gateway::gr_block__nitems_read(), and tag_sink_demo::work().

uint64_t gr_block::nitems_written ( unsigned int  which_output)

Return the number of items written on output stream which_output.

Referenced by gr_block_gateway::gr_block__nitems_written(), block_gateway::gr_block__nitems_written(), and tag_source_demo::work().

int gr_block::output_multiple ( ) const [inline]
bool gr_block::output_multiple_set ( ) const [inline]
gr_tag_t gr_block::pop_msg_queue ( void  ) [protected]

Pop a message from the front of the queue. This function will block until a message is available.

Returns:
the message as a tag type

Referenced by gr_block_gateway::gr_block__pop_msg_queue(), and block_gateway::gr_block__pop_msg_queue().

void gr_block::post_msg ( const std::string group,
const gr_tag_t msg 
) [protected]

Post a message to a subscriber group. All message subscribers in the group will get this message.

Parameters:
groupthe name of the subscriber group
msgthe message to post to all subscribers

Referenced by gr_block_gateway::gr_block__post_msg(), and block_gateway::gr_block__post_msg().

void gr_block::post_msg ( const std::string group,
const pmt::pmt_t key,
const pmt::pmt_t value,
const pmt::pmt_t srcid = pmt::PMT_F 
) [inline, protected]

Post a message to a subscriber group.

Parameters:
groupthe name of the subscriber group
keythe tag key as a PMT symbol
valueany PMT holding any value for the given key
srcidoptional source ID specifier; defaults to PMT_F

References gr_tag_t::offset, gr_tag_t::key, gr_tag_t::value, and gr_tag_t::srcid.

void gr_block::produce ( int  which_output,
int  how_many_items 
)

Tell the scheduler how_many_items were produced on output stream which_output.

If the block's general_work method calls produce, general_work must return WORK_CALLED_PRODUCE.

Referenced by gr_block_gateway::gr_block__produce(), and block_gateway::gr_block__produce().

void gr_block::push_msg_queue ( const gr_tag_t msg) [protected]

Enqueue a message into this block. Usually this is called internally. However, it may be useful for the block itself or an outside entity to post messages to the block. Ex: Push can be used to wake up a thread blocking on pop_msg_queue.

Parameters:
msgthe message to enqueue

Referenced by gr_block_gateway::gr_block__push_msg_queue(), and block_gateway::gr_block__push_msg_queue().

double gr_block::relative_rate ( ) const [inline]
void gr_block::set_alignment ( int  multiple)

Constrains buffers to work on a set item alignment (for SIMD)

set_alignment_multiple causes the scheduler to ensure that the noutput_items argument passed to forecast and general_work will be an integer multiple of

Parameters:
multipleThe default value is 1.

This control is similar to the output_multiple setting, except that if the number of items passed to the block is less than the output_multiple, this value is ignored and the block can produce like normal. The d_unaligned value is set to the number of items the block is off by. In the next call to general_work, the noutput_items is set to d_unaligned or less until d_unaligned==0. The buffers are now aligned again and the aligned calls can be performed again.

void gr_block::set_detail ( gr_block_detail_sptr  detail) [inline]
void gr_block::set_fixed_rate ( bool  fixed_rate) [inline, protected]
void gr_block::set_history ( unsigned  history) [inline]
void gr_block::set_is_unaligned ( bool  u)
void gr_block::set_output_multiple ( int  multiple)

Constrain the noutput_items argument passed to forecast and general_work.

set_output_multiple causes the scheduler to ensure that the noutput_items argument passed to forecast and general_work will be an integer multiple of

Parameters:
multipleThe default value of output multiple is 1.

Referenced by gr_block_gateway::gr_block__set_output_multiple(), block_gateway::gr_block__set_output_multiple(), and gr_sync_interpolator::set_interpolation().

void gr_block::set_relative_rate ( double  relative_rate)

Set the approximate output rate / input rate.

Provide a hint to the buffer allocator and scheduler. The default relative_rate is 1.0

decimators have relative_rates < 1.0 interpolators have relative_rates > 1.0

Referenced by gr_block_gateway::gr_block__set_relative_rate(), block_gateway::gr_block__set_relative_rate(), gr_pfb_arb_resampler_ccf::set_rate(), gr_pfb_arb_resampler_fff::set_rate(), gr_sync_decimator::set_decimation(), and gr_sync_interpolator::set_interpolation().

void gr_block::set_tag_propagation_policy ( tag_propagation_policy_t  p)

Set the policy by the scheduler to determine how tags are moved downstream.

Referenced by gr_block_gateway::gr_block__set_tag_propagation_policy(), and block_gateway::gr_block__set_tag_propagation_policy().

void gr_block::set_unaligned ( int  na)
virtual bool gr_block::start ( ) [virtual]

Called to enable drivers, etc for i/o devices.

This allows a block to enable an associated driver to begin transfering data just before we start to execute the scheduler. The end result is that this reduces latency in the pipeline when dealing with audio devices, usrps, etc.

Reimplemented in audio_osx_source, and audio_osx_sink.

virtual bool gr_block::stop ( ) [virtual]

Called to disable drivers, etc for i/o devices.

Reimplemented in audio_osx_source, and audio_osx_sink.

tag_propagation_policy_t gr_block::tag_propagation_policy ( )

Asks for the policy used by the scheduler to moved tags downstream.

Referenced by gr_block_gateway::gr_block__tag_propagation_policy(), and block_gateway::gr_block__tag_propagation_policy().

int gr_block::unaligned ( ) const [inline]

Friends And Related Function Documentation

friend class gr_tpb_thread_body [friend]

Reimplemented from gr_basic_block.


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