Add option to pad TAGPacket in different ways

5 files changed, 55 insertions, 4 deletions

diff --git a/src/dabOutput/dabOutput.h b/src/dabOutput/dabOutput.h
index c8ce9f2..cd48790 100644
--- a/src/dabOutput/dabOutput.h
+++ b/src/dabOutput/dabOutput.h
@@ -64,6 +64,7 @@ struct edi_configuration_t {
     bool enable_pft;
     std::string dest_addr;
     unsigned int dest_port;
+    unsigned int tagpacket_alignment;
 };
 
 
diff --git a/src/dabOutput/edi/TagItems.cpp b/src/dabOutput/edi/TagItems.cpp
index 2cae7d1..b97721a 100644
--- a/src/dabOutput/edi/TagItems.cpp
+++ b/src/dabOutput/edi/TagItems.cpp
@@ -171,5 +171,25 @@ std::vector<uint8_t> TagESTn::Assemble()
     */
     return packet;
 }
+
+std::vector<uint8_t> TagStarDMY::Assemble()
+{
+    std::string pack_data("*dmy");
+    std::vector<uint8_t> packet(pack_data.begin(), pack_data.end());
+
+    packet.resize(4 + 4 + length_);
+
+    const uint32_t length_bits = length_ * 8;
+
+    packet[4] = (length_bits >> 24) & 0xFF;
+    packet[5] = (length_bits >> 16) & 0xFF;
+    packet[6] = (length_bits >> 8) & 0xFF;
+    packet[7] = length_bits & 0xFF;
+
+    // The remaining bytes in the packet are "undefined data"
+
+    return packet;
+}
+
 #endif
 
diff --git a/src/dabOutput/edi/TagItems.h b/src/dabOutput/edi/TagItems.h
index fccea2d..e75d241 100644
--- a/src/dabOutput/edi/TagItems.h
+++ b/src/dabOutput/edi/TagItems.h
@@ -111,5 +111,18 @@ class TagESTn : public TagItem
     private:
         uint8_t id_;
 };
+
+// ETSI TS 102 821, 5.2.2.2 Dummy padding
+class TagStarDMY : public TagItem
+{
+    public:
+        /* length is the TAG value length in bytes */
+        TagStarDMY(uint32_t length) : length_(length) {}
+        std::vector<uint8_t> Assemble();
+
+    private:
+        uint32_t length_;
+};
+
 #endif
 
diff --git a/src/dabOutput/edi/TagPacket.cpp b/src/dabOutput/edi/TagPacket.cpp
index aa4f23b..435c071 100644
--- a/src/dabOutput/edi/TagPacket.cpp
+++ b/src/dabOutput/edi/TagPacket.cpp
@@ -33,6 +33,8 @@
 #include <stdint.h>
 #include <cassert>
 
+TagPacket::TagPacket(unsigned int alignment) : m_alignment(alignment)
+{ }
 
 std::vector<uint8_t> TagPacket::Assemble()
 {
@@ -49,10 +51,21 @@ std::vector<uint8_t> TagPacket::Assemble()
         //std::cerr << "     Add TAGItem of length " << tag_data.size() << std::endl;
     }
 
-    // Add padding
-    while (packet.size() % 8 > 0)
-    {
-        packet.push_back(0); // TS 102 821, 5.1, "padding shall be undefined"
+    if (m_alignment == 0) { /* no padding */ }
+    else if (m_alignment == 8) {
+        // Add padding inside TAG packet
+        while (packet.size() % 8 > 0) {
+            packet.push_back(0); // TS 102 821, 5.1, "padding shall be undefined"
+        }
+    }
+    else if (m_alignment > 8) {
+        TagStarDMY dmy(m_alignment - 8);
+        auto dmy_data = dmy.Assemble();
+        packet.insert(packet.end(), dmy_data.begin(), dmy_data.end());
+    }
+    else {
+        std::cerr << "Invalid alignment requirement " << m_alignment <<
+            " defined in TagPacket" << std::endl;
     }
 
     return packet;
diff --git a/src/dabOutput/edi/TagPacket.h b/src/dabOutput/edi/TagPacket.h
index 9d69226..5ad1904 100644
--- a/src/dabOutput/edi/TagPacket.h
+++ b/src/dabOutput/edi/TagPacket.h
@@ -42,9 +42,13 @@
 class TagPacket
 {
     public:
+        TagPacket(unsigned int alignment);
         std::vector<uint8_t> Assemble();
 
         std::list<TagItem*> tag_items;
+
+    private:
+        unsigned int m_alignment;
 };
 
 #endif