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Re: [Discuss-gnuradio] gnuradio block for boolean operations
From: |
Ed Criscuolo |
Subject: |
Re: [Discuss-gnuradio] gnuradio block for boolean operations |
Date: |
Mon, 18 Feb 2008 10:43:04 -0500 |
User-agent: |
Thunderbird 2.0.0.9 (Macintosh/20071031) |
Tim Meehan wrote:
Hello all,
I want to perform some simple boolean operations on a stream of data.
For example invert the bits from the output of the demodulators or convert
from NRZ to NRZI
I was thinking something like
1) gr_xor_bb, gr_and_bb, gr_or_bb, br_not_bb ...
or
2) maybe gr_boolean("xor") , gr_boolean("and") ...
Is this something someone has started?
I have written both xor_bb and nrzi_to_nrz_bb and used them
on 2 different projects.
Is there another way I should go about this?
If this is something that should be done can someone give me an idea of
the desired format (1 or 2 or something else)
Purely from the point of view of "cohesion" I would recommend
the "gr_xor_bb" form instead of passing in a selector that
determines the behavior. Although I must admit, I wrestled
for quite a while with writing so much infrastructure code
for something as simple an an "xor".
Here's the code for gr_nrzi_to_nrz_bb. The code for xor
is similar.
@(^.^)@ Ed
/* -*- c++ -*- */
/*
* Copyright 2006 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 2, 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 <gr_nrzi_to_nrz_bb.h>
#include <gr_io_signature.h>
#include <stdexcept>
gr_nrzi_to_nrz_bb_sptr
gr_make_nrzi_to_nrz_bb (bool preload)
{
return gr_nrzi_to_nrz_bb_sptr (new gr_nrzi_to_nrz_bb (preload));
}
gr_nrzi_to_nrz_bb::gr_nrzi_to_nrz_bb (bool preload)
: gr_sync_block ("nrzi_to_nrz_bb",
gr_make_io_signature (1, 1, sizeof (unsigned char)),
gr_make_io_signature (1, 1, sizeof (unsigned char))),
d_prev_nrzi_bit(preload)
{
}
int
gr_nrzi_to_nrz_bb::work (int noutput_items,
gr_vector_const_void_star &input_items,
gr_vector_void_star &output_items)
{
const unsigned char* in = (const unsigned char *) input_items[0];
unsigned char* out = (unsigned char *) output_items[0];
unsigned char nrzi_bit;
unsigned char nrz_bit;
for (int i = 0; i < noutput_items; i++)
{
nrzi_bit = in[i];
// Convert NRZI to NRZ.
if(nrzi_bit != d_prev_nrzi_bit)
{
nrz_bit = 0;
}
else
{
nrz_bit = 1;
}
out[i] = nrz_bit;
d_prev_nrzi_bit = nrzi_bit;
}
return noutput_items;
}