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+/*
+ Copyright (C) 2014 CSP Innovazione nelle ICT s.c.a r.l. (http://www.csp.it/)
+ Copyright (C) 2016 Matthias P. Braendli (http://www.opendigitalradio.org)
+ Copyright (C) 2015 Data Path
+
+ This program 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 of the License, or
+ (at your option) any later version.
+
+ This program 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 this program. If not, see <http://www.gnu.org/licenses/>.
+
+ Authors:
+ Sergio Sagliocco <sergio.sagliocco@csp.it>
+ Matthias P. Braendli <matthias@mpb.li>
+ / | |- ')|) |-|_ _ (|,_ .| _ ,_ \
+ Data Path \(|(||_(|/_| (||_||(a)_||||(|||.(_()|||/
+
+*/
+
+#pragma once
+#include <vector>
+#include <sstream>
+#include "utils.hpp"
+
+class WatermarkDecoder
+{
+ public:
+ WatermarkDecoder() {}
+
+ void push_confind_bit(bool confind)
+ {
+ // The ConfInd of FIG 0/10 contains the CRC-DABMUX and ODR-DabMux watermark
+ m_confind_bits.push_back(confind);
+ }
+
+ std::string calculate_watermark()
+ {
+ // First try to find the 0x55 0x55 sync in the waternark data
+ size_t bit_ix;
+ int alternance_count = 0;
+ bool last_bit = 1;
+ for (bit_ix = 0; bit_ix < m_confind_bits.size(); bit_ix++) {
+ if (alternance_count == 16) {
+ break;
+ }
+ else {
+ if (last_bit != m_confind_bits[bit_ix]) {
+ last_bit = m_confind_bits[bit_ix];
+ alternance_count++;
+ }
+ else {
+ alternance_count = 0;
+ last_bit = 1;
+ }
+ }
+
+ }
+
+ printf("Found SYNC at offset %zu out of %zu\n", bit_ix - alternance_count, m_confind_bits.size());
+
+ std::stringstream watermark_ss;
+
+ uint8_t b = 0;
+ size_t i = 0;
+ while (bit_ix < m_confind_bits.size()) {
+
+ b |= m_confind_bits[bit_ix] << (7 - i);
+
+ if (i == 7) {
+ watermark_ss << (char)b;
+
+ b = 0;
+ i = 0;
+ }
+ else {
+ i++;
+ }
+
+ bit_ix += 2;
+ }
+
+ return watermark_ss.str();
+ }
+
+ private:
+ const WatermarkDecoder& operator=(const WatermarkDecoder&) = delete;
+ WatermarkDecoder(const WatermarkDecoder&) = delete;
+
+ std::vector<bool> m_confind_bits;
+};
+