1 files changed, 300 insertions, 0 deletions
diff --git a/lib/edi/common.cpp b/lib/edi/common.cpp
new file mode 100644
index 0000000..bc0fa1b
--- /dev/null
+++ b/lib/edi/common.cpp
@@ -0,0 +1,300 @@
+/*
+   Copyright (C) 2019
+   Matthias P. Braendli, matthias.braendli@mpb.li
+
+   http://opendigitalradio.org
+
+    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 2 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, write to the Free Software Foundation, Inc.,
+    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+#include "common.hpp"
+#include "buffer_unpack.hpp"
+#include "Log.h"
+#include "crc.h"
+#include <iomanip>
+#include <sstream>
+#include <cassert>
+#include <cstdio>
+
+namespace EdiDecoder {
+
+using namespace std;
+
+string frame_timestamp_t::to_string() const
+{
+    const time_t seconds_in_unix_epoch = to_unix_epoch();
+
+    stringstream ss;
+    ss << "Timestamp: " << std::put_time(std::gmtime(&seconds_in_unix_epoch), "%c %Z");
+    return ss.str();
+}
+
+time_t frame_timestamp_t::to_unix_epoch() const
+{
+    // EDI epoch: 2000-01-01T00:00:00Z
+    // Convert using
+    // TZ=UTC python -c 'import datetime; print(datetime.datetime(2000,1,1,0,0,0,0).strftime("%s"))'
+    return 946684800 + seconds - utco;
+}
+
+
+TagDispatcher::TagDispatcher(
+        std::function<void()>&& af_packet_completed, bool verbose) :
+    m_af_packet_completed(move(af_packet_completed))
+{
+    m_pft.setVerbose(verbose);
+}
+
+void TagDispatcher::push_bytes(const vector<uint8_t> &buf)
+{
+    copy(buf.begin(), buf.end(), back_inserter(m_input_data));
+
+    while (m_input_data.size() > 2) {
+        if (m_input_data[0] == 'A' and m_input_data[1] == 'F') {
+            const decode_state_t st = decode_afpacket(m_input_data);
+
+            if (st.num_bytes_consumed == 0 and not st.complete) {
+                // We need to refill our buffer
+                break;
+            }
+
+            if (st.num_bytes_consumed) {
+                vector<uint8_t> remaining_data;
+                copy(m_input_data.begin() + st.num_bytes_consumed,
+                        m_input_data.end(),
+                        back_inserter(remaining_data));
+                m_input_data = remaining_data;
+            }
+
+            if (st.complete) {
+                m_af_packet_completed();
+            }
+        }
+        else if (m_input_data[0] == 'P' and m_input_data[1] == 'F') {
+            PFT::Fragment fragment;
+            const size_t fragment_bytes = fragment.loadData(m_input_data);
+
+            if (fragment_bytes == 0) {
+                // We need to refill our buffer
+                break;
+            }
+
+            vector<uint8_t> remaining_data;
+            copy(m_input_data.begin() + fragment_bytes,
+                    m_input_data.end(),
+                    back_inserter(remaining_data));
+            m_input_data = remaining_data;
+
+            if (fragment.isValid()) {
+                m_pft.pushPFTFrag(fragment);
+            }
+
+            auto af = m_pft.getNextAFPacket();
+            if (not af.empty()) {
+                decode_state_t st = decode_afpacket(af);
+
+                if (st.complete) {
+                    m_af_packet_completed();
+                }
+            }
+        }
+        else {
+            etiLog.log(warn,"Unknown %c!", *m_input_data.data());
+            m_input_data.erase(m_input_data.begin());
+        }
+    }
+}
+
+void TagDispatcher::push_packet(const vector<uint8_t> &buf)
+{
+    if (buf.size() < 2) {
+        throw std::invalid_argument("Not enough bytes to read EDI packet header");
+    }
+
+    if (buf[0] == 'A' and buf[1] == 'F') {
+        const decode_state_t st = decode_afpacket(buf);
+
+        if (st.complete) {
+            m_af_packet_completed();
+        }
+
+    }
+    else if (buf[0] == 'P' and buf[1] == 'F') {
+        PFT::Fragment fragment;
+        fragment.loadData(buf);
+
+        if (fragment.isValid()) {
+            m_pft.pushPFTFrag(fragment);
+        }
+
+        auto af = m_pft.getNextAFPacket();
+        if (not af.empty()) {
+            const decode_state_t st = decode_afpacket(af);
+
+            if (st.complete) {
+                m_af_packet_completed();
+            }
+        }
+    }
+    else {
+        const char packettype[3] = {(char)buf[0], (char)buf[1], '\0'};
+        std::stringstream ss;
+        ss << "Unknown EDI packet ";
+        ss << packettype;
+        throw std::invalid_argument(ss.str());
+    }
+}
+
+void TagDispatcher::setMaxDelay(int num_af_packets)
+{
+    m_pft.setMaxDelay(num_af_packets);
+}
+
+
+#define AFPACKET_HEADER_LEN 10 // includes SYNC
+decode_state_t TagDispatcher::decode_afpacket(
+        const std::vector<uint8_t> &input_data)
+{
+    if (input_data.size() < AFPACKET_HEADER_LEN) {
+        return {false, 0};
+    }
+
+    // read length from packet
+    uint32_t taglength = read_32b(input_data.begin() + 2);
+    uint16_t seq = read_16b(input_data.begin() + 6);
+
+    const size_t crclength = 2;
+    if (input_data.size() < AFPACKET_HEADER_LEN + taglength + crclength) {
+        return {false, 0};
+    }
+
+    if (m_last_seq + 1 != seq) {
+        etiLog.level(warn) << "EDI AF Packet sequence error, " << seq;
+    }
+    m_last_seq = seq;
+
+    bool has_crc = (input_data[8] & 0x80) ? true : false;
+    uint8_t major_revision = (input_data[8] & 0x70) >> 4;
+    uint8_t minor_revision = input_data[8] & 0x0F;
+    if (major_revision != 1 or minor_revision != 0) {
+        throw invalid_argument("EDI AF Packet has wrong revision " +
+                to_string(major_revision) + "." + to_string(minor_revision));
+    }
+    uint8_t pt = input_data[9];
+    if (pt != 'T') {
+        // only support Tag
+        return {false, 0};
+    }
+
+
+    if (not has_crc) {
+        throw invalid_argument("AF packet not supported, has no CRC");
+    }
+
+    uint16_t crc = 0xffff;
+    for (size_t i = 0; i < AFPACKET_HEADER_LEN + taglength; i++) {
+        crc = crc16(crc, &input_data[i], 1);
+    }
+    crc ^= 0xffff;
+
+    uint16_t packet_crc = read_16b(input_data.begin() + AFPACKET_HEADER_LEN + taglength);
+
+    if (packet_crc != crc) {
+        throw invalid_argument(
+                "AF Packet crc wrong");
+    }
+    else {
+        vector<uint8_t> payload(taglength);
+        copy(input_data.begin() + AFPACKET_HEADER_LEN,
+                input_data.begin() + AFPACKET_HEADER_LEN + taglength,
+                payload.begin());
+
+        return {decode_tagpacket(payload),
+            AFPACKET_HEADER_LEN + taglength + 2};
+    }
+}
+
+void TagDispatcher::register_tag(const std::string& tag, tag_handler&& h)
+{
+    m_handlers[tag] = move(h);
+}
+
+
+bool TagDispatcher::decode_tagpacket(const vector<uint8_t> &payload)
+{
+    size_t length = 0;
+
+    bool success = true;
+
+    for (size_t i = 0; i + 8 < payload.size(); i += 8 + length) {
+        char tag_sz[5];
+        tag_sz[4] = '\0';
+        copy(payload.begin() + i, payload.begin() + i + 4, tag_sz);
+
+        string tag(tag_sz);
+
+        uint32_t taglength = read_32b(payload.begin() + i + 4);
+
+        if (taglength % 8 != 0) {
+            etiLog.log(warn, "Invalid tag length!");
+            break;
+        }
+        taglength /= 8;
+
+        length = taglength;
+
+        vector<uint8_t> tag_value(taglength);
+        copy(   payload.begin() + i+8,
+                payload.begin() + i+8+taglength,
+                tag_value.begin());
+
+        bool tagsuccess = false;
+        bool found = false;
+        for (auto tag_handler : m_handlers) {
+            if (tag_handler.first.size() == 4 and tag_handler.first == tag) {
+                found = true;
+                tagsuccess = tag_handler.second(tag_value, 0);
+            }
+            else if (tag_handler.first.size() == 3 and
+                    tag.substr(0, 3) == tag_handler.first) {
+                found = true;
+                uint8_t n = tag_sz[3];
+                tagsuccess = tag_handler.second(tag_value, n);
+            }
+            else if (tag_handler.first.size() == 2 and
+                    tag.substr(0, 2) == tag_handler.first) {
+                found = true;
+                uint16_t n = 0;
+                n = (uint16_t)(tag_sz[2]) << 8;
+                n |= (uint16_t)(tag_sz[3]);
+                tagsuccess = tag_handler.second(tag_value, n);
+            }
+        }
+
+        if (not found) {
+            etiLog.log(warn, "Ignoring unknown TAG %s", tag.c_str());
+            break;
+        }
+
+        if (not tagsuccess) {
+            etiLog.log(warn, "Error decoding TAG %s", tag.c_str());
+            success = tagsuccess;
+            break;
+        }
+    }
+
+    return success;
+}
+
+}