#!/usr/bin/env python

#

# Copyright 2007,2010 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.

# 

from gnuradio import gr, gr_unittest

class test_glfsr_source(gr_unittest.TestCase):

    def setUp (self):

        self.tb = gr.top_block ()

    def tearDown (self):

        self.tb = None

    def test_000_make_b(self):

        src = gr.glfsr_source_b(16)

        self.assertEquals(src.mask(), 0x8016)

        self.assertEquals(src.period(), 2**16-1)

    def test_001_degree_b(self):

        self.assertRaises(RuntimeError,

                          lambda: gr.glfsr_source_b(0))

        self.assertRaises(RuntimeError,

                          lambda: gr.glfsr_source_b(33))

    def test_002_correlation_b(self):

        for degree in range(1,11):                # Higher degrees take too long to correlate

            src = gr.glfsr_source_b(degree, False)

            b2f = gr.chunks_to_symbols_bf((-1.0,1.0), 1)

            dst = gr.vector_sink_f()

            del self.tb # Discard existing top block

            self.tb = gr.top_block()

            self.tb.connect(src, b2f, dst)

            self.tb.run()

            self.tb.disconnect_all()

            actual_result = dst.data()

            R = auto_correlate(actual_result)

            self.assertEqual(R[0], float(len(R))) # Auto-correlation peak at origin

            for i in range(len(R)-1):

                self.assertEqual(R[i+1], -1.0)    # Auto-correlation minimum everywhere else

    def test_003_make_f(self):

        src = gr.glfsr_source_f(16)

        self.assertEquals(src.mask(), 0x8016)

        self.assertEquals(src.period(), 2**16-1)

    def test_004_degree_f(self):

        self.assertRaises(RuntimeError,

                          lambda: gr.glfsr_source_f(0))

        self.assertRaises(RuntimeError,

                          lambda: gr.glfsr_source_f(33))

    def test_005_correlation_f(self):

        for degree in range(1,11):                # Higher degrees take too long to correlate

            src = gr.glfsr_source_f(degree, False)

            dst = gr.vector_sink_f()

            del self.tb # Discard existing top block

            self.tb = gr.top_block()

            self.tb.connect(src, dst)

            self.tb.run()

            actual_result = dst.data()

            R = auto_correlate(actual_result)

            self.assertEqual(R[0], float(len(R))) # Auto-correlation peak at origin

            for i in range(len(R)-1):

                self.assertEqual(R[i+1], -1.0)    # Auto-correlation minimum everywhere else

def auto_correlate(data):

    l = len(data)

    R = [0,]*l

    for lag in range(l):

        for i in range(l):

            R[lag] += data[i]*data[i-lag]

    return R

if __name__ == '__main__':

    gr_unittest.run(test_glfsr_source, "test_glfsr_source.xml")