From 03967733d70220e2de7af3cdad320aec5c82ede1 Mon Sep 17 00:00:00 2001
From: "Matthias P. Braendli" <matthias.braendli@mpb.li>
Date: Tue, 25 Jun 2019 10:50:23 +0200
Subject: Add more EDI input improvements

---
 lib/edi/PFT.hpp | 166 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 166 insertions(+)
 create mode 100644 lib/edi/PFT.hpp

(limited to 'lib/edi/PFT.hpp')

diff --git a/lib/edi/PFT.hpp b/lib/edi/PFT.hpp
new file mode 100644
index 0000000..779509b
--- /dev/null
+++ b/lib/edi/PFT.hpp
@@ -0,0 +1,166 @@
+/* ------------------------------------------------------------------
+ * 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;
+};
+
+}
+
+}
-- 
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