diff options
| author | Marcus Müller <mmueller@gnuradio.org> | 2021-06-20 18:44:37 +0200 |
|---|---|---|
| committer | mormj <34754695+mormj@users.noreply.github.com> | 2021-06-28 10:19:20 -0400 |
| commit | a695142b33199de25327709d4983592d96e20414 (patch) | |
| tree | 135068aeef5b447b30ae2a20e252f0a3f0520430 /gr-blocks | |
| parent | 5463e741ef6714854e4623288eb74e21eb1cca90 (diff) | |
blocks: zero-output, zero-copy Head mode
If you don't want to test a stream with an exact number of input, but
just want your flow graph to terminate after a given number of items,
having a head block without an output enables you to do that without
copying the data from Head's in- to its output.
Signed-off-by: Marcus Müller <mmueller@gnuradio.org>
Diffstat (limited to 'gr-blocks')
| -rw-r--r-- | gr-blocks/grc/blocks_head.block.yml | 1 | ||||
| -rw-r--r-- | gr-blocks/include/gnuradio/blocks/head.h | 11 | ||||
| -rw-r--r-- | gr-blocks/lib/head_impl.cc | 10 | ||||
| -rw-r--r-- | gr-blocks/python/blocks/bindings/head_python.cc | 2 |
4 files changed, 19 insertions, 5 deletions
diff --git a/gr-blocks/grc/blocks_head.block.yml b/gr-blocks/grc/blocks_head.block.yml index 6f8d1787eb..2a3e5d9de3 100644 --- a/gr-blocks/grc/blocks_head.block.yml +++ b/gr-blocks/grc/blocks_head.block.yml @@ -30,6 +30,7 @@ outputs: - domain: stream dtype: ${ type } vlen: ${ vlen } + optional: true asserts: - ${ vlen > 0 } diff --git a/gr-blocks/include/gnuradio/blocks/head.h b/gr-blocks/include/gnuradio/blocks/head.h index 0e28c6d3b1..d8a34bf502 100644 --- a/gr-blocks/include/gnuradio/blocks/head.h +++ b/gr-blocks/include/gnuradio/blocks/head.h @@ -1,6 +1,7 @@ /* -*- c++ -*- */ /* * Copyright 2004,2009,2012,2013 Free Software Foundation, Inc. + * Copyright 2021 Marcus Müller * * This file is part of GNU Radio * @@ -19,11 +20,17 @@ namespace gr { namespace blocks { /*! - * \brief copies the first N items to the output then signals done + * \brief stop after processing the first N items * \ingroup misc_blk * * \details - * Useful for building test cases + * Useful for building test cases, this block consumes only N items from its input, and + * copies them to its output, if that is connected. + * + * You can hence use this block in series with your sample flow if you want a block + * downstream of it to be tested with an exact number of input items; or you can put it in + * parallel to your data path, so that it stops at most one buffer size after the + * specified number of items has been produced upstream. */ class BLOCKS_API head : virtual public sync_block { diff --git a/gr-blocks/lib/head_impl.cc b/gr-blocks/lib/head_impl.cc index 0ee22682d0..567a12d1df 100644 --- a/gr-blocks/lib/head_impl.cc +++ b/gr-blocks/lib/head_impl.cc @@ -1,6 +1,7 @@ /* -*- c++ -*- */ /* * Copyright 2004,2009,2013 Free Software Foundation, Inc. + * Copyright 2021 Marcus Müller * * This file is part of GNU Radio * @@ -27,7 +28,7 @@ head::sptr head::make(size_t sizeof_stream_item, uint64_t nitems) head_impl::head_impl(size_t sizeof_stream_item, uint64_t nitems) : sync_block("head", io_signature::make(1, 1, sizeof_stream_item), - io_signature::make(1, 1, sizeof_stream_item)), + io_signature::make(0, 1, sizeof_stream_item)), d_nitems(nitems), d_ncopied_items(0) { @@ -47,7 +48,12 @@ int head_impl::work(int noutput_items, if (n == 0) return 0; - memcpy(output_items[0], input_items[0], n * input_signature()->sizeof_stream_item(0)); + // can have zero or one output port, if zero, don't copy + if (!output_items.empty()) { + memcpy(output_items[0], + input_items[0], + n * input_signature()->sizeof_stream_item(0)); + } d_ncopied_items += n; return n; diff --git a/gr-blocks/python/blocks/bindings/head_python.cc b/gr-blocks/python/blocks/bindings/head_python.cc index bc02a00a9b..33ba41cb3e 100644 --- a/gr-blocks/python/blocks/bindings/head_python.cc +++ b/gr-blocks/python/blocks/bindings/head_python.cc @@ -14,7 +14,7 @@ /* BINDTOOL_GEN_AUTOMATIC(0) */ /* BINDTOOL_USE_PYGCCXML(0) */ /* BINDTOOL_HEADER_FILE(head.h) */ -/* BINDTOOL_HEADER_FILE_HASH(d0c0087ad00f1b1d3f09273ba0dcb7d6) */ +/* BINDTOOL_HEADER_FILE_HASH(eef877add2d06c4e1e1a3ba48f498ad3) */ /***********************************************************************************/ #include <pybind11/complex.h> |