cea608tocea708: create service's as requested

Allows the ability to push multiple Service blocks of the same service
into the same packet if necessary (unlikely but possible).

Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-rs/-/merge_requests/1398>

video/closedcaption/src/cea608tocea708/imp.rs

@@ -101,11 +101,11 @@ impl Cea708ServiceState {
             0
         };
         match cea608_mode {
-            Cea608Mode::PopOn => self.writer.popon_preamble().unwrap(),
+            Cea608Mode::PopOn => self.writer.popon_preamble(),
-            Cea608Mode::PaintOn => self.writer.paint_on_preamble().unwrap(),
+            Cea608Mode::PaintOn => self.writer.paint_on_preamble(),
-            Cea608Mode::RollUp2 => self.writer.rollup_preamble(2, base_row).unwrap(),
+            Cea608Mode::RollUp2 => self.writer.rollup_preamble(2, base_row),
-            Cea608Mode::RollUp3 => self.writer.rollup_preamble(3, base_row).unwrap(),
+            Cea608Mode::RollUp3 => self.writer.rollup_preamble(3, base_row),
-            Cea608Mode::RollUp4 => self.writer.rollup_preamble(4, base_row).unwrap(),
+            Cea608Mode::RollUp4 => self.writer.rollup_preamble(4, base_row),
         };
         // we have redefined then window so all the attributes have been reset
         self.pen_location.row = new_row;
@@ -117,20 +117,20 @@ impl Cea708ServiceState {
 
     fn handle_text(&mut self, text: Cea608Text) {
         if text.code_space == CodeSpace::WestEU {
-            self.writer.push_codes(&[Code::BS]).unwrap();
+            self.writer.push_codes(&[Code::BS]);
         }
         if let Some(c) = text.char1 {
             if self.pen_location.column > 31 {
-                self.writer.push_codes(&[Code::BS]).unwrap();
+                self.writer.push_codes(&[Code::BS]);
             }
-            self.writer.write_char(c).unwrap();
+            self.writer.write_char(c);
             self.pen_location.column = std::cmp::min(self.pen_location.column + 1, 32);
         }
         if let Some(c) = text.char2 {
             if self.pen_location.column > 31 {
-                self.writer.push_codes(&[Code::BS]).unwrap();
+                self.writer.push_codes(&[Code::BS]);
             }
-            self.writer.write_char(c).unwrap();
+            self.writer.write_char(c);
             self.pen_location.column = std::cmp::min(self.pen_location.column + 1, 32);
         }
     }
@@ -150,7 +150,7 @@ impl Cea708ServiceState {
         }
 
         if need_pen_location {
-            self.writer.set_pen_location(self.pen_location).unwrap();
+            self.writer.set_pen_location(self.pen_location);
         }
 
         let mut need_pen_attributes = false;
@@ -165,20 +165,20 @@ impl Cea708ServiceState {
         }
 
         if need_pen_attributes {
-            self.writer.set_pen_attributes(self.pen_attributes).unwrap();
+            self.writer.set_pen_attributes(self.pen_attributes);
         }
 
         if self.pen_color.foreground_color != textstyle_foreground_color(preamble.style) {
             self.pen_color.foreground_color = textstyle_foreground_color(preamble.style);
-            self.writer.set_pen_color(self.pen_color).unwrap();
+            self.writer.set_pen_color(self.pen_color);
         }
     }
 
     fn handle_midrowchange(&mut self, midrowchange: MidRowChange) {
-        self.writer.write_char(' ').unwrap();
+        self.writer.write_char(' ');
         if self.pen_color.foreground_color != textstyle_foreground_color(midrowchange.style) {
             self.pen_color.foreground_color = textstyle_foreground_color(midrowchange.style);
-            self.writer.set_pen_color(self.pen_color).unwrap();
+            self.writer.set_pen_color(self.pen_color);
         }
 
         let mut need_pen_attributes = false;
@@ -214,7 +214,7 @@ impl Cea708State {
         self.packet_counter &= 0x3;
 
         for state in self.service_state.iter_mut() {
-            if let Some(service) = state.writer.take_service() {
+            while let Some(service) = state.writer.take_service(packet.free_space()) {
                 if let Err(e) = packet.push_service(service.clone()) {
                     gst::warning!(
                         CAT,
@@ -307,14 +307,8 @@ impl State {
             {
                 // https://www.law.cornell.edu/cfr/text/47/79.101 (f)(1)(x)
                 gst::trace!(CAT, "change to rollup from pop/paint-on");
-                self.cea708.service_state[idx]
+                self.cea708.service_state[idx].writer.clear_hidden_window();
-                    .writer
+                self.cea708.service_state[idx].writer.clear_current_window();
-                    .clear_hidden_window()
-                    .unwrap();
-                self.cea708.service_state[idx]
-                    .writer
-                    .clear_current_window()
-                    .unwrap();
                 self.cea608.service[idx].base_row = 15;
             }
             if old_mode.is_rollup() && cea608_mode.is_rollup() {
@@ -331,8 +325,7 @@ impl State {
                     for _ in new_count..old_count {
                         self.cea708.service_state[idx]
                             .writer
-                            .push_codes(&[Code::CR])
+                            .push_codes(&[Code::CR]);
-                            .unwrap();
                     }
                 }
             }
@@ -371,8 +364,8 @@ impl State {
                 }
                 Cea608::EndOfCaption(chan) => {
                     let state = self.service_state_from_608_field_channel(field, chan);
-                    state.writer.end_of_caption().unwrap();
+                    state.writer.end_of_caption();
-                    state.writer.etx().unwrap();
+                    state.writer.etx();
                 }
                 Cea608::Preamble(mut preamble) => {
                     let idx = self.field_channel_to_index(field, preamble.chan);
@@ -394,8 +387,7 @@ impl State {
                         if old_base_row != preamble.row as u8 {
                             state
                                 .writer
-                                .rollup_preamble(rollup_count, preamble.row as u8)
+                                .rollup_preamble(rollup_count, preamble.row as u8);
-                                .unwrap();
                         }
                         state.pen_location.row = rollup_count - 1;
                         preamble.row = rollup_count as i32 - 1;
@@ -411,10 +403,7 @@ impl State {
                     let state = self.service_state_from_608_field_channel(field, chan);
                     // TODO: handle removing a midrowchange
                     state.pen_location.column = std::cmp::max(state.pen_location.column - 1, 0);
-                    state
+                    state.writer.push_codes(&[cea708_types::tables::Code::BS]);
-                        .writer
-                        .push_codes(&[cea708_types::tables::Code::BS])
-                        .unwrap();
                 }
                 Cea608::CarriageReturn(chan) => {
                     if let Some(mode) =
@@ -428,11 +417,11 @@ impl State {
                 }
                 Cea608::EraseDisplay(chan) => {
                     let state = self.service_state_from_608_field_channel(field, chan);
-                    state.writer.clear_current_window().unwrap();
+                    state.writer.clear_current_window();
                 }
                 Cea608::EraseNonDisplay(chan) => {
                     let state = self.service_state_from_608_field_channel(field, chan);
-                    state.writer.clear_hidden_window().unwrap();
+                    state.writer.clear_hidden_window();
                 }
                 Cea608::TabOffset(chan, count) => {
                     let state = self.service_state_from_608_field_channel(field, chan);
@@ -453,8 +442,7 @@ impl State {
                     // and we need to send ETX
                     self.cea708.service_state[idx]
                         .writer
-                        .push_codes(&[cea708_types::tables::Code::ETX])
+                        .push_codes(&[cea708_types::tables::Code::ETX]);
-                        .unwrap();
                 }
             }
         }

video/closedcaption/src/cea708utils.rs

@@ -88,14 +88,8 @@ pub fn textstyle_to_pen_color(style: TextStyle) -> SetPenColorArgs {
     }
 }
 
-#[derive(Debug)]
-pub enum WriteError {
-    // returns the number of characters/bytes written
-    WouldOverflow(usize),
-}
-
 pub(crate) struct Cea708ServiceWriter {
-    service: Option<Service>,
+    codes: Vec<Code>,
     service_no: u8,
     active_window: WindowBits,
     hidden_window: WindowBits,
@@ -104,24 +98,44 @@ pub(crate) struct Cea708ServiceWriter {
 impl Cea708ServiceWriter {
     pub fn new(service_no: u8) -> Self {
         Self {
-            service: None,
+            codes: vec![],
             service_no,
             active_window: WindowBits::ZERO,
             hidden_window: WindowBits::ONE,
         }
     }
 
-    fn ensure_service(&mut self) {
+    pub fn take_service(&mut self, available_bytes: usize) -> Option<Service> {
-        if self.service.is_none() {
+        if self.codes.is_empty() {
-            self.service = Some(Service::new(self.service_no));
+            return None;
         }
+
+        gst::trace!(CAT, "New service block {}", self.service_no);
+        let mut service = Service::new(self.service_no);
+        let mut i = 0;
+        for code in self.codes.iter() {
+            if code.byte_len() > service.free_space() {
+                gst::trace!(CAT, "service is full");
+                break;
+            }
+            if service.len() + code.byte_len() > available_bytes {
+                gst::trace!(CAT, "packet is full");
+                break;
+            }
+            gst::trace!(CAT, "Adding code {code:?} to service");
+            match service.push_code(code) {
+                Ok(_) => i += 1,
+                Err(_) => break,
+            }
+        }
+        if i == 0 {
+            return None;
+        }
+        self.codes = self.codes.split_off(i);
+        Some(service)
     }
 
-    pub fn take_service(&mut self) -> Option<Service> {
+    pub fn popon_preamble(&mut self) {
-        self.service.take()
-    }
-
-    pub fn popon_preamble(&mut self) -> Result<usize, WriteError> {
         gst::trace!(CAT, "popon_preamble");
         let window = match self.hidden_window {
             // switch up the newly defined window
@@ -152,26 +166,24 @@ impl Cea708ServiceWriter {
         self.push_codes(&codes)
     }
 
-    pub fn clear_current_window(&mut self) -> Result<usize, WriteError> {
+    pub fn clear_current_window(&mut self) {
         gst::trace!(CAT, "clear_current_window {:?}", self.active_window);
         self.push_codes(&[Code::ClearWindows(self.active_window)])
     }
 
-    pub fn clear_hidden_window(&mut self) -> Result<usize, WriteError> {
+    pub fn clear_hidden_window(&mut self) {
         gst::trace!(CAT, "clear_hidden_window");
         self.push_codes(&[Code::ClearWindows(self.hidden_window)])
     }
 
-    pub fn end_of_caption(&mut self) -> Result<usize, WriteError> {
+    pub fn end_of_caption(&mut self) {
         gst::trace!(CAT, "end_of_caption");
-        let ret =
+        self.push_codes(&[Code::ToggleWindows(self.active_window | self.hidden_window)]);
-            self.push_codes(&[Code::ToggleWindows(self.active_window | self.hidden_window)])?;
         std::mem::swap(&mut self.active_window, &mut self.hidden_window);
         gst::trace!(CAT, "active window {:?}", self.active_window);
-        Ok(ret)
     }
 
-    pub fn paint_on_preamble(&mut self) -> Result<usize, WriteError> {
+    pub fn paint_on_preamble(&mut self) {
         gst::trace!(CAT, "paint_on_preamble");
         let window = match self.active_window {
             WindowBits::ZERO => 0,
@@ -198,7 +210,7 @@ impl Cea708ServiceWriter {
         ])
     }
 
-    pub fn rollup_preamble(&mut self, rollup_count: u8, base_row: u8) -> Result<usize, WriteError> {
+    pub fn rollup_preamble(&mut self, rollup_count: u8, base_row: u8) {
         let base_row = std::cmp::max(rollup_count, base_row);
         let anchor_vertical = (base_row as u32 * 100 / 15) as u8;
         gst::trace!(
@@ -229,49 +241,34 @@ impl Cea708ServiceWriter {
         self.push_codes(&codes)
     }
 
-    pub fn write_char(&mut self, c: char) -> Result<usize, WriteError> {
+    pub fn write_char(&mut self, c: char) {
         if let Some(code) = Code::from_char(c) {
             self.push_codes(&[code])
-        } else {
-            Ok(0)
         }
     }
 
-    pub fn push_codes(&mut self, codes: &[Code]) -> Result<usize, WriteError> {
+    pub fn push_codes(&mut self, codes: &[Code]) {
-        self.ensure_service();
+        gst::log!(CAT, "pushing codes: {codes:?}");
-        let service = self.service.as_mut().unwrap();
+        self.codes.extend(codes.iter().cloned());
-        let start_len = service.len();
-        if service.free_space() < codes.iter().map(|c| c.byte_len()).sum::<usize>() {
-            return Err(WriteError::WouldOverflow(0));
-        }
-        for code in codes.iter() {
-            gst::trace!(
-                CAT,
-                "pushing for service:{} code: {code:?}",
-                service.number()
-            );
-            service.push_code(code).unwrap();
-        }
-        Ok(service.len() - start_len)
     }
 
-    pub fn etx(&mut self) -> Result<usize, WriteError> {
+    pub fn etx(&mut self) {
         self.push_codes(&[Code::ETX])
     }
 
-    pub fn carriage_return(&mut self) -> Result<usize, WriteError> {
+    pub fn carriage_return(&mut self) {
         self.push_codes(&[Code::CR])
     }
 
-    pub fn set_pen_attributes(&mut self, args: SetPenAttributesArgs) -> Result<usize, WriteError> {
+    pub fn set_pen_attributes(&mut self, args: SetPenAttributesArgs) {
         self.push_codes(&[Code::SetPenAttributes(args)])
     }
 
-    pub fn set_pen_location(&mut self, args: SetPenLocationArgs) -> Result<usize, WriteError> {
+    pub fn set_pen_location(&mut self, args: SetPenLocationArgs) {
         self.push_codes(&[Code::SetPenLocation(args)])
     }
 
-    pub fn set_pen_color(&mut self, args: SetPenColorArgs) -> Result<usize, WriteError> {
+    pub fn set_pen_color(&mut self, args: SetPenColorArgs) {
         self.push_codes(&[Code::SetPenColor(args)])
     }
 }