#include <gr_block.h>
Inheritance diagram for gr_block:
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.
Public Member Functions | |
| virtual | ~gr_block () |
| std::string | name () const |
| gr_io_signature_sptr | input_signature () const |
| gr_io_signature_sptr | output_signature () const |
| long | unique_id () const |
| 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 | check_topology (int ninputs, int noutputs) |
| Confirm that ninputs and noutputs is an acceptable combination. | |
| 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 |
| 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 | 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. | |
| gr_block_detail_sptr | detail () const |
| void | set_detail (gr_block_detail_sptr detail) |
Protected Member Functions | |
| gr_block (const std::string &name, gr_io_signature_sptr input_signature, gr_io_signature_sptr output_signature) | |
| void | set_input_signature (gr_io_signature_sptr iosig) |
| may only be called during constructor | |
| void | set_output_signature (gr_io_signature_sptr iosig) |
| may only be called during constructor | |
| void | set_fixed_rate (bool fixed_rate) |
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Confirm that ninputs and noutputs is an acceptable combination.
Reimplemented in gr_align_on_samplenumbers_ss, gr_chunks_to_symbols_bc, gr_chunks_to_symbols_bf, gr_chunks_to_symbols_ic, gr_chunks_to_symbols_if, gr_chunks_to_symbols_sc, gr_chunks_to_symbols_sf, gr_deinterleave, gr_interleave, gr_kludge_copy, gr_packed_to_unpacked_bb, gr_packed_to_unpacked_ii, gr_packed_to_unpacked_ss, gr_test, gr_unpacked_to_packed_bb, gr_unpacked_to_packed_ii, gr_unpacked_to_packed_ss, and gr_oscope_sink_f. |
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Tell the scheduler
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Tell the scheduler
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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. |
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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_sync_block, gr_sync_decimator, and gr_test. |
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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_sync_block, gr_sync_decimator, gr_sync_interpolator, and gr_test. |
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Estimate input requirements given output request.
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 gr_fractional_interpolator, gr_rational_resampler_base_ccc, gr_rational_resampler_base_ccf, gr_rational_resampler_base_fcc, gr_rational_resampler_base_fff, gr_rational_resampler_base_fsf, gr_rational_resampler_base_scc, gr_align_on_samplenumbers_ss, gr_clock_recovery_mm_cc, gr_clock_recovery_mm_ff, gr_dd_mpsk_sync_cc, gr_packed_to_unpacked_bb, gr_packed_to_unpacked_ii, gr_packed_to_unpacked_ss, gr_simple_framer, gr_sync_block, gr_sync_decimator, gr_sync_interpolator, gr_test, gr_unpacked_to_packed_bb, gr_unpacked_to_packed_ii, and gr_unpacked_to_packed_ss. |
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compute output items from input items
Implemented in gr_fractional_interpolator, gr_rational_resampler_base_ccc, gr_rational_resampler_base_ccf, gr_rational_resampler_base_fcc, gr_rational_resampler_base_fff, gr_rational_resampler_base_fsf, gr_rational_resampler_base_scc, gr_align_on_samplenumbers_ss, gr_clock_recovery_mm_cc, gr_clock_recovery_mm_ff, gr_dd_mpsk_sync_cc, gr_keep_one_in_n, gr_nop, gr_packed_to_unpacked_bb, gr_packed_to_unpacked_ii, gr_packed_to_unpacked_ss, gr_simple_correlator, gr_simple_framer, gr_squelch_base_cc, gr_squelch_base_ff, gr_sync_block, gr_sync_decimator, gr_sync_interpolator, gr_test, gr_unpacked_to_packed_bb, gr_unpacked_to_packed_ii, and gr_unpacked_to_packed_ss. |
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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. Reimplemented in gr_rational_resampler_base_ccc, gr_rational_resampler_base_ccf, gr_rational_resampler_base_fcc, gr_rational_resampler_base_fff, gr_rational_resampler_base_fsf, and gr_rational_resampler_base_scc. |
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return the approximate output rate / input rate
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may only be called during constructor
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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
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may only be called during constructor
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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 |
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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. |
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Called to disable drivers, etc for i/o devices.
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1.4.1