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authorMatthias P. Braendli <matthias.braendli@mpb.li>2019-08-21 10:11:35 +0200
committerMatthias P. Braendli <matthias.braendli@mpb.li>2019-08-21 10:11:35 +0200
commit86ea8cd8b8b5af7917db28ae30cfb2d2886868fe (patch)
tree7222d8e077dd2155eecac68b8c78330bcfe5dc80 /lib/edi/PFT.hpp
parent86fbf91f7323a2c5626a357b8414b15e20c19c9e (diff)
parent5ee85c4ac41337e383eb1a735bc05f1e5d46a98f (diff)
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Merge branch 'ediInput' into next
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+/* ------------------------------------------------------------------
+ * Copyright (C) 2017 AVT GmbH - Fabien Vercasson
+ * Copyright (C) 2017 Matthias P. Braendli
+ * matthias.braendli@mpb.li
+ *
+ * http://opendigitalradio.org
+ *
+ * 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.
+ * -------------------------------------------------------------------
+ */
+
+#pragma once
+#include <stdio.h>
+#include <vector>
+#include <map>
+#include <stdint.h>
+
+namespace EdiDecoder {
+namespace PFT {
+
+using pseq_t = uint16_t;
+using findex_t = uint32_t; // findex is a 24-bit value
+
+class Fragment
+{
+ public:
+ // Load the data for one fragment from buf into
+ // the Fragment.
+ // \returns the number of bytes of useful data found in buf
+ // A non-zero return value doesn't imply a valid fragment
+ // the isValid() method must be used to verify this.
+ size_t loadData(const std::vector<uint8_t> &buf);
+
+ bool isValid() const { return _valid; }
+ pseq_t Pseq() const { return _Pseq; }
+ findex_t Findex() const { return _Findex; }
+ findex_t Fcount() const { return _Fcount; }
+ bool FEC() const { return _FEC; }
+ uint16_t Plen() const { return _Plen; }
+ uint8_t RSk() const { return _RSk; }
+ uint8_t RSz() const { return _RSz; }
+ const std::vector<uint8_t>& payload() const
+ { return _payload; }
+
+ bool checkConsistency(const Fragment& other) const;
+
+ private:
+ std::vector<uint8_t> _payload;
+
+ pseq_t _Pseq = 0;
+ findex_t _Findex = 0;
+ findex_t _Fcount = 0;
+ bool _FEC = false;
+ bool _Addr = false;
+ uint16_t _Plen = 0;
+ uint8_t _RSk = 0;
+ uint8_t _RSz = 0;
+ uint16_t _Source = 0;
+ uint16_t _Dest = 0;
+ bool _valid = false;
+};
+
+/* The AFBuilder collects Fragments and builds an Application Frame
+ * out of them. It does error correction if necessary
+ */
+class AFBuilder
+{
+ public:
+ enum class decode_attempt_result_t {
+ yes, // The AF packet can be build because all fragments are present
+ maybe, // RS decoding may correctly decode the AF packet
+ no, // Not enough fragments present to permit RS
+ };
+
+ static std::string dar_to_string(decode_attempt_result_t dar) {
+ switch (dar) {
+ case decode_attempt_result_t::yes: return "y";
+ case decode_attempt_result_t::no: return "n";
+ case decode_attempt_result_t::maybe: return "m";
+ }
+ return "?";
+ }
+
+ AFBuilder(pseq_t Pseq, findex_t Fcount, size_t lifetime);
+
+ void pushPFTFrag(const Fragment &frag);
+
+ /* Assess if it may be possible to decode this AF packet */
+ decode_attempt_result_t canAttemptToDecode() const;
+
+ /* Try to build the AF with received fragments.
+ * Apply error correction if necessary (missing packets/CRC errors)
+ * \return an empty vector if building the AF is not possible
+ */
+ std::vector<uint8_t> extractAF(void) const;
+
+ std::pair<findex_t, findex_t>
+ numberOfFragments(void) const {
+ return {_fragments.size(), _Fcount};
+ }
+
+ std::string visualise(void) const;
+
+ /* The user of this instance can keep track of the lifetime of this
+ * builder
+ */
+ size_t lifeTime;
+
+ private:
+
+ // A map from fragment index to fragment
+ std::map<findex_t, Fragment> _fragments;
+
+ // cached version of decoded AF packet
+ mutable std::vector<uint8_t> _af_packet;
+
+ pseq_t _Pseq;
+ findex_t _Fcount;
+};
+
+class PFT
+{
+ public:
+ void pushPFTFrag(const Fragment &fragment);
+
+ /* Try to build the AF packet for the next pseq. This might
+ * skip one or more pseq according to the maximum delay setting.
+ *
+ * \return an empty vector if building the AF is not possible
+ */
+ std::vector<uint8_t> getNextAFPacket(void);
+
+ /* Set the maximum delay in number of AF Packets before we
+ * abandon decoding a given pseq.
+ */
+ void setMaxDelay(size_t num_af_packets);
+
+ /* Enable verbose fprintf */
+ void setVerbose(bool enable);
+
+ private:
+ void incrementNextPseq(void);
+
+ pseq_t m_next_pseq;
+ size_t m_max_delay = 10; // in AF packets
+
+ // Keep one AFBuilder for each Pseq
+ std::map<pseq_t, AFBuilder> m_afbuilders;
+
+ bool m_verbose = 0;
+};
+
+}
+
+}