dcwfilter.c

#if 0
# 
# Copyright (c) 2014 - 2015 Javier Sayago <admin@lonasdigital.com>
# Contact: javilonas@esp-desarrolladores.com
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#    http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
#endif

int32_t checksumDCW(uint8 *data)
{
	if(data[3] != (byte)((data[0] + data[1] + data[2]) & 0xFF) || data[7] != (byte)((data[4] + data[5] + data[6]) & 0xFF)) {
		return 0;
	}
	if(data[11] != (byte)((data[8] + data[9] + data[10]) & 0xFF) || data[15] != (byte)((data[12] + data[13] + data[14]) & 0xFF)) {
		return 0;
	}
	return 1;
}


int32_t isnullDCW(uint8 *data)
{
	int32_t a1 = (!data[0] && !data[1] && !data[2]) || (!data[4] && !data[5] && !data[6]);
	int32_t a2 = (!data[8] && !data[9] && !data[10]) || (!data[12] && !data[13] && !data[14]);
	return (a1 && a2);
}

int32_t isbadDCW(uint8 *data)
{
	int32_t a0 = ((data[0]&0xF0)==(data[1]&0xF0))&&((data[0]&0xF0)==(data[2]&0xF0));
	int32_t a1 = ((data[4]&0xF0)==(data[5]&0xF0))&&((data[4]&0xF0)==(data[6]&0xF0));
	int32_t a2 = ((data[8]&0xF0)==(data[9]&0xF0))&&((data[8]&0xF0)==(data[10]&0xF0));
	int32_t a3 = ((data[12]&0xF0)==(data[13]&0xF0))&&((data[12]&0xF0)==(data[14]&0xF0));
	return ( (a0&&a1)&&(a2&&a3) );
}

int32_t acceptDCW(uint8 *data)
{
	if (!checksumDCW(data)) return 0;
	if ( isnullDCW(data) ) return 0;
	if ( isbadDCW(data) ) return 0;

	struct dcw_data *dcw = cfg.bad_dcw;
	while (dcw) {
		if (!memcmp(dcw->dcw, data, 16)) return 0;
		dcw = dcw->next;
	}

	return 1;
}