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/* -*- c++ -*- */
/*
* Copyright 2005,2007,2010,2013 Free Software Foundation, Inc.
*
* This file is part of GNU Radio
*
* SPDX-License-Identifier: GPL-3.0-or-later
*
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include "skiphead_impl.h"
#include <gnuradio/io_signature.h>
#include <cstring>
namespace gr {
namespace blocks {
skiphead::sptr skiphead::make(size_t itemsize, uint64_t nitems_to_skip)
{
return gnuradio::make_block_sptr<skiphead_impl>(itemsize, nitems_to_skip);
}
skiphead_impl::skiphead_impl(size_t itemsize, uint64_t nitems_to_skip)
: block("skiphead",
io_signature::make(1, 1, itemsize),
io_signature::make(1, 1, itemsize)),
d_nitems_to_skip(nitems_to_skip),
d_nitems(0)
{
// Reserve space for a few tags to avoid constant re-allocation
// in the call to get_tags_in_window
d_tags.reserve(8);
// We'll handle propagating tags our selves to handle shifting offsets of tags
set_tag_propagation_policy(TPP_DONT);
}
skiphead_impl::~skiphead_impl() {}
int skiphead_impl::general_work(int noutput_items,
gr_vector_int& ninput_items_,
gr_vector_const_void_star& input_items,
gr_vector_void_star& output_items)
{
const char* in = (const char*)input_items[0];
char* out = (char*)output_items[0];
int ninput_items = std::min(ninput_items_[0], noutput_items);
int ii = 0; // input index
while (ii < ninput_items) {
uint64_t ni_total = ii + d_nitems; // total items processed so far
if (ni_total < d_nitems_to_skip) { // need to skip some more
int n_to_skip =
(int)std::min(d_nitems_to_skip - ni_total, (uint64_t)(ninput_items - ii));
ii += n_to_skip;
}
else { // nothing left to skip. copy away
// Grab all tags in the window and shift their offsets appropriately
get_tags_in_window(d_tags, 0, ii, ninput_items);
for (auto& tag : d_tags) {
tag.offset -= d_nitems_to_skip;
add_item_tag(0, tag);
}
int n_to_copy = ninput_items - ii;
if (n_to_copy > 0) {
size_t itemsize = output_signature()->sizeof_stream_item(0);
memcpy(out, in + (ii * itemsize), n_to_copy * itemsize);
}
d_nitems += ninput_items;
consume_each(ninput_items);
return n_to_copy;
}
}
d_nitems += ninput_items;
consume_each(ninput_items);
return 0;
}
} /* namespace blocks */
} /* namespace gr */
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