Add FIG2 options for character field and text control

6 files changed, 155 insertions, 64 deletions

diff --git a/doc/example.mux b/doc/example.mux
index caa4d2d..76d6828 100644
--- a/doc/example.mux
+++ b/doc/example.mux
@@ -124,7 +124,19 @@ ensemble {
     ; The FIG2 label can be up to 16 characters long, and is in UTF-8.
     ;fig2_label "ÓpêñÐigıtålRadiō"
 
-    ; There is no FIG2 short label for the moment.
+    ; FIG2 labels can either be sent with a character field (old spec)
+    ; or with a text control (new draftETSI TS 103 176 v2.2.1).
+    ; If unspecified, defaults to setting the text control with the values
+    ; shown in the example below.
+    ;
+    ;fig2_label_character_flag "0xFF00"
+    ;
+    ;fig2_label_text_control {
+    ; bidi false
+    ; base_direction "LTR"
+    ; contextual false
+    ; combining false
+    ;}
 }
 
 ; Definition of DAB services
diff --git a/src/ConfigParser.cpp b/src/ConfigParser.cpp
index 62d81c7..fb49efc 100644
--- a/src/ConfigParser.cpp
+++ b/src/ConfigParser.cpp
@@ -81,13 +81,42 @@ static uint16_t get_announcement_flag_from_ptree(ptree& pt)
     return flags;
 }
 
+static void parse_fig2_label(ptree& pt, DabLabel& label) {
+    label.setFIG2Label(pt.get<string>("fig2_label", ""));
+
+    uint16_t character_field = hexparse(pt.get("fig2_label_character_flag", "0"));
+    if (character_field) {
+        label.setFIG2CharacterField(character_field);
+    }
+
+    auto pt_tc = pt.get_child_optional("fig2_label_text_control");
+    if (pt_tc) {
+        FIG2TextControl tc;
+        tc.bidi_flag = pt_tc->get<bool>("bidi", tc.bidi_flag);
+        auto base_direction = pt_tc->get<string>("bidi", "LTR");
+
+        if (not(base_direction == "LTR" or base_direction == "RTL")) {
+            tc.base_direction_is_rtl = (base_direction == "RTL");
+        }
+        else {
+            etiLog.level(error) << "Invalid value " << base_direction <<
+                " for fig2 text control base direction";
+            throw runtime_error("Invalid FIG2 text control definition");
+        }
+
+        tc.contextual_flag = pt_tc->get<bool>("contextual", tc.contextual_flag);
+        tc.combining_flag = pt_tc->get<bool>("combining", tc.combining_flag);
+
+        label.setFIG2TextControl(tc);
+    }
+}
+
 // Parse the linkage section
 static void parse_linkage(ptree& pt,
         std::shared_ptr<dabEnsemble> ensemble)
 {
     auto pt_linking = pt.get_child_optional("linking");
-    if (pt_linking)
-    {
+    if (pt_linking) {
         for (const auto& it : *pt_linking) {
             const string setuid = it.first;
             const ptree pt_set = it.second;
@@ -447,7 +476,7 @@ static void parse_general(ptree& pt,
             abort();
     }
 
-    ensemble->label.setFIG2Label(pt_ensemble.get<string>("fig2_label", ""));
+    parse_fig2_label(pt_ensemble, ensemble->label);
 
     try {
         ptree pt_announcements = pt_ensemble.get_child("announcements");
@@ -586,7 +615,7 @@ void parse_ptree(
                 abort();
         }
 
-        service->label.setFIG2Label(pt_service.get<string>("fig2_label", ""));
+        parse_fig2_label(pt_service, service->label);
 
         service->id = new_service_id;
         service->ecc = hexparse(pt_service.get("ecc", "0"));
@@ -748,7 +777,7 @@ void parse_ptree(
                 abort();
         }
 
-        component->label.setFIG2Label(pt_comp.get<string>("fig2_label", ""));
+        parse_fig2_label(pt_comp, component->label);
 
         if (component->SCIdS == 0 and not component->label.long_label().empty()) {
             etiLog.level(warn) << "Primary component " << component->uid <<
diff --git a/src/MuxElements.cpp b/src/MuxElements.cpp
index b7536b6..8c14d9a 100644
--- a/src/MuxElements.cpp
+++ b/src/MuxElements.cpp
@@ -347,6 +347,18 @@ int DabLabel::setFIG2Label(const std::string& label)
     return 0;
 }
 
+void DabLabel::setFIG2CharacterField(uint16_t character_field)
+{
+    m_fig2_use_text_control = false;
+    m_fig2_character_field = character_field;
+}
+
+void DabLabel::setFIG2TextControl(FIG2TextControl tc)
+{
+    m_fig2_use_text_control = true;
+    m_fig2_text_control = tc;
+}
+
 void DabLabel::writeLabel(uint8_t* buf) const
 {
     memset(buf, ' ', DABLABEL_LENGTH);
diff --git a/src/MuxElements.h b/src/MuxElements.h
index 2e35e6a..9107a41 100644
--- a/src/MuxElements.h
+++ b/src/MuxElements.h
@@ -143,6 +143,13 @@ struct dabOutput {
 
 #define DABLABEL_LENGTH 16
 
+struct FIG2TextControl {
+    bool bidi_flag = false;
+    bool base_direction_is_rtl = false;
+    bool contextual_flag = false;
+    bool combining_flag = false;
+};
+
 class DabLabel
 {
     public:
@@ -172,20 +179,34 @@ class DabLabel
          */
         int setFIG2Label(const std::string& label);
 
+        /* FIG2 can either be sent with a character field (old spec)
+         * or with a text control (draftETSI TS 103 176 v2.2.1).
+         *
+         * Setting one clears the other, and selects the value of the
+         * Rfu bit in the FIG 2 Data Field
+         */
+        void setFIG2CharacterField(uint16_t character_field);
+        void setFIG2TextControl(FIG2TextControl tc);
+
+        // For FIG 1
+
         /* Write the label to the 16-byte buffer given in buf
          * In the DAB standard, the label is 16 bytes long, and is
          * padded using spaces.
          */
         void writeLabel(uint8_t* buf) const;
 
-        // For FIG 1
-        bool has_fig1_label() const { return not m_fig1_label.empty(); };
+        bool has_fig1_label() const { return not m_fig1_label.empty(); }
         uint16_t flag() const { return m_fig1_flag; }
         const std::string long_label() const;
         const std::string short_label() const;
 
         // For FIG 2
-        bool has_fig2_label() const { return not m_fig2_label.empty(); };
+        bool has_fig2_label() const { return not m_fig2_label.empty(); }
+        bool fig2_uses_text_control() const { return m_fig2_use_text_control; }
+        FIG2TextControl fig2_text_control() const { return m_fig2_text_control; }
+        uint16_t fig2_character_field() const { return m_fig2_character_field; }
+
         const std::string fig2_label() const;
 
         /* FIG 2 labels are either in UCS-2 or in UTF-8. Because there are upcoming
@@ -208,6 +229,10 @@ class DabLabel
         /* FIG2 label, stored in UTF-8. TODO: support UCS-2 */
         std::string m_fig2_label;
 
+        bool m_fig2_use_text_control = true; // Default to the new variant
+        uint16_t m_fig2_character_field = 0xFF00;
+        FIG2TextControl m_fig2_text_control;
+
         /* Checks and calculates the flag. slabel must be EBU Latin Charset */
         int setFIG1ShortLabel(const std::string& slabel);
 };
diff --git a/src/fig/FIG2.cpp b/src/fig/FIG2.cpp
index b88814c..7aecbe8 100644
--- a/src/fig/FIG2.cpp
+++ b/src/fig/FIG2.cpp
@@ -34,6 +34,44 @@ namespace FIC {
 
 using namespace std;
 
+static void write_fig2_segment_field(
+        uint8_t *buf, ssize_t& remaining, FIG2_Segments& segments, const DabLabel& label)
+{
+    if (segments.current_segment_index() == 0) {
+        // EN 300 401 5.2.2.3.3 "The second segment shall be carried in a following
+        // FIG type 2 data field ...", i.e. do not insert the header anymore.
+        if (label.fig2_uses_text_control()) {
+            auto ext = (FIG2_Extended_Label_WithTextControl*)buf;
+            auto tc = label.fig2_text_control();
+            ext->TextControl =
+                (tc.bidi_flag ? 0x8 : 0) |
+                (tc.base_direction_is_rtl ? 0x4 : 0) |
+                (tc.contextual_flag ? 0x2 : 0) |
+                (tc.combining_flag ? 0x1 : 0);
+            ext->SegmentCount = segments.segment_count();
+            ext->EncodingFlag = 0; // UTF-8
+
+            buf += sizeof(FIG2_Extended_Label_WithTextControl);
+            remaining -= sizeof(FIG2_Extended_Label_WithTextControl);
+        }
+        else {
+            auto ext = (FIG2_Extended_Label_WithCharacterFlag*)buf;
+            ext->Rfa = 0;
+            ext->SegmentCount = segments.segment_count();
+            ext->EncodingFlag = 0; // UTF-8
+            ext->CharacterFlag = htons(label.fig2_character_field());
+
+            buf += sizeof(FIG2_Extended_Label_WithCharacterFlag);
+            remaining -= sizeof(FIG2_Extended_Label_WithCharacterFlag);
+        }
+    }
+
+    const auto character_field = segments.advance_segment();
+    copy(character_field.begin(), character_field.end(), buf);
+    buf += character_field.size();
+    remaining -= character_field.size();
+}
+
 void FIG2_Segments::clear()
 {
     segments.clear();
@@ -132,8 +170,12 @@ FillStatus FIG2_0::fill(uint8_t *buf, size_t max_size)
         }
     }
 
+    const size_t segment_header_length = ensemble->label.fig2_uses_text_control() ?
+        sizeof(FIG2_Extended_Label_WithTextControl) :
+        sizeof(FIG2_Extended_Label_WithCharacterFlag);
+
     const ssize_t required_bytes = (m_segments.current_segment_index() == 0) ?
-        sizeof(FIGtype2) + 2 + sizeof(FIG2_Extended_Label) + m_segments.current_segment_length() :
+        sizeof(FIGtype2) + 2 + segment_header_length + m_segments.current_segment_length() :
         sizeof(FIGtype2) + 2 + m_segments.current_segment_length();
 
     if (remaining < required_bytes) {
@@ -147,7 +189,7 @@ FillStatus FIG2_0::fill(uint8_t *buf, size_t max_size)
     fig2->FIGtypeNumber = 2;
 
     fig2->Extension = 0;
-    fig2->Rfu = 0;
+    fig2->Rfu = ensemble->label.fig2_uses_text_control() ? 1 : 0;
     fig2->SegmentIndex = m_segments.current_segment_index();
     fig2->ToggleFlag = m_segments.toggle_flag();
 
@@ -160,23 +202,7 @@ FillStatus FIG2_0::fill(uint8_t *buf, size_t max_size)
     buf += 2;
     remaining -= 2;
 
-    if (m_segments.current_segment_index() == 0) {
-        // EN 300 401 5.2.2.3.3 "The second segment shall be carried in a following
-        // FIG type 2 data field ...", i.e. do not insert the header anymore.
-        auto ext = (FIG2_Extended_Label*)buf;
-        ext->Rfa = 0;
-        ext->SegmentCount = m_segments.segment_count();
-        ext->EncodingFlag = 0; // UTF-8
-        ext->CharacterFlag = htons(0xFF00); // Short label always truncation
-
-        buf += sizeof(FIG2_Extended_Label);
-        remaining -= sizeof(FIG2_Extended_Label);
-    }
-
-    const auto character_field = m_segments.advance_segment();
-    copy(character_field.begin(), character_field.end(), buf);
-    buf += character_field.size();
-    remaining -= character_field.size();
+    write_fig2_segment_field(buf, remaining, m_segments, ensemble->label);
 
     if (m_segments.complete()) {
         fs.complete_fig_transmitted = true;
@@ -218,8 +244,13 @@ FillStatus FIG2_1_and_5::fill(uint8_t *buf, size_t max_size)
 
             const size_t id_length = (is_programme ? 2 : 4);
 
-            const ssize_t required_bytes = sizeof(FIGtype2) + id_length + segments.current_segment_length() +
-                ((segments.current_segment_index() == 0) ? sizeof(FIG2_Extended_Label) : 0);
+            const size_t segment_header_length = ensemble->label.fig2_uses_text_control() ?
+                sizeof(FIG2_Extended_Label_WithTextControl) :
+                sizeof(FIG2_Extended_Label_WithCharacterFlag);
+
+            const ssize_t required_bytes = sizeof(FIGtype2) + id_length +
+                segments.current_segment_length() +
+                ((segments.current_segment_index() == 0) ? segment_header_length : 0);
 
             if (remaining < required_bytes) {
                 break;
@@ -231,7 +262,7 @@ FillStatus FIG2_1_and_5::fill(uint8_t *buf, size_t max_size)
             fig2->FIGtypeNumber = 2;
 
             fig2->Extension = figextension();
-            fig2->Rfu = 0;
+            fig2->Rfu = (*service)->label.fig2_uses_text_control() ? 1 : 0;
             fig2->SegmentIndex = segments.current_segment_index();
             fig2->ToggleFlag = segments.toggle_flag();
 
@@ -252,21 +283,7 @@ FillStatus FIG2_1_and_5::fill(uint8_t *buf, size_t max_size)
             buf += id_length;
             remaining -= id_length;
 
-            if (segments.current_segment_index() == 0) {
-                auto ext = (FIG2_Extended_Label*)buf;
-                ext->Rfa = 0;
-                ext->SegmentCount = segments.segment_count();
-                ext->EncodingFlag = 0; // UTF-8
-                ext->CharacterFlag = htons(0xFF00); // Short label always truncation
-
-                buf += sizeof(FIG2_Extended_Label);
-                remaining -= sizeof(FIG2_Extended_Label);
-            }
-
-            const auto character_field = segments.advance_segment();
-            copy(character_field.begin(), character_field.end(), buf);
-            buf += character_field.size();
-            remaining -= character_field.size();
+            write_fig2_segment_field(buf, remaining, segments, (*service)->label);
 
             if (segments.complete()) {
                 segments.clear();
@@ -321,8 +338,12 @@ FillStatus FIG2_4::fill(uint8_t *buf, size_t max_size)
                 sizeof(FIGtype2_4_Programme_Identifier) :
                 sizeof(FIGtype2_4_Data_Identifier);
 
+            const size_t segment_header_length = (*component)->label.fig2_uses_text_control() ?
+                    sizeof(FIG2_Extended_Label_WithTextControl) :
+                    sizeof(FIG2_Extended_Label_WithCharacterFlag);
+
             const ssize_t required_bytes = sizeof(FIGtype2) + id_length + segments.current_segment_length() +
-                ((segments.current_segment_index() == 0) ? sizeof(FIG2_Extended_Label) : 0);
+                ((segments.current_segment_index() == 0) ? segment_header_length : 0);
 
             if (remaining < required_bytes) {
                 break;
@@ -334,7 +355,7 @@ FillStatus FIG2_4::fill(uint8_t *buf, size_t max_size)
             fig2->FIGtypeNumber = 2;
 
             fig2->Extension = 4;
-            fig2->Rfu = 0;
+            fig2->Rfu = (*component)->label.fig2_uses_text_control() ? 1 : 0;
             fig2->SegmentIndex = segments.current_segment_index();
             fig2->ToggleFlag = segments.toggle_flag();
 
@@ -365,21 +386,7 @@ FillStatus FIG2_4::fill(uint8_t *buf, size_t max_size)
                 remaining -= sizeof(FIGtype2_4_Data_Identifier);
             }
 
-            if (segments.current_segment_index() == 0) {
-                auto ext = (FIG2_Extended_Label*)buf;
-                ext->Rfa = 0;
-                ext->SegmentCount = segments.segment_count();
-                ext->EncodingFlag = 0; // UTF-8
-                ext->CharacterFlag = htons(0xFF00); // Short label always truncation
-
-                buf += sizeof(FIG2_Extended_Label);
-                remaining -= sizeof(FIG2_Extended_Label);
-            }
-
-            const auto character_field = segments.advance_segment();
-            copy(character_field.begin(), character_field.end(), buf);
-            buf += character_field.size();
-            remaining -= character_field.size();
+            write_fig2_segment_field(buf, remaining, segments, (*component)->label);
 
             if (segments.complete()) {
                 segments.clear();
diff --git a/src/fig/FIG2.h b/src/fig/FIG2.h
index 6fad658..ee3fed9 100644
--- a/src/fig/FIG2.h
+++ b/src/fig/FIG2.h
@@ -145,7 +145,7 @@ struct FIGtype2_4_Data_Identifier {
     uint32_t SId;
 } PACKED;
 
-struct FIG2_Extended_Label {
+struct FIG2_Extended_Label_WithCharacterFlag {
     uint8_t Rfa:4;
     uint8_t SegmentCount:3;
     uint8_t EncodingFlag:1;
@@ -153,6 +153,12 @@ struct FIG2_Extended_Label {
     uint16_t CharacterFlag;
 } PACKED;
 
+struct FIG2_Extended_Label_WithTextControl {
+    uint8_t TextControl:4;
+    uint8_t SegmentCount:3;
+    uint8_t EncodingFlag:1;
+} PACKED;
+
 #ifdef _WIN32
 #   pragma pack(pop)
 #endif