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/* -*- c++ -*- */
/*
* Copyright 2005,2007,2010,2013 Free Software Foundation, Inc.
*
* This file is part of GNU Radio
*
* GNU Radio is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3, or (at your option)
* any later version.
*
* GNU Radio is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with GNU Radio; see the file COPYING. If not, write to
* the Free Software Foundation, Inc., 51 Franklin Street,
* Boston, MA 02110-1301, USA.
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include "skiphead_impl.h"
#include <gr_io_signature.h>
#include <string.h>
namespace gr {
namespace blocks {
skiphead::sptr
skiphead::make(size_t itemsize, uint64_t nitems_to_skip)
{
return gnuradio::get_initial_sptr
(new skiphead_impl(itemsize, nitems_to_skip));
}
skiphead_impl::skiphead_impl(size_t itemsize, uint64_t nitems_to_skip)
: gr_block("skiphead",
gr_make_io_signature(1, 1, itemsize),
gr_make_io_signature(1, 1, itemsize)),
d_nitems_to_skip(nitems_to_skip), d_nitems(0)
{
}
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
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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