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parser: add conversion from a parsed Cea608 value into the relevant Code/s #13

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merged 3 commits into from
Nov 28, 2024
Merged

parser: add conversion from a parsed Cea608 value into the relevant Code/s #13

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b020712
tables: fix tab offset construction
ystreet Nov 28, 2024
4c7e55f
cea608: add conversion into Code values
ystreet Nov 28, 2024
30b39f4
writer: ignore NUL padding data when pushing data for writing
ystreet Nov 28, 2024
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218 changes: 218 additions & 0 deletions src/lib.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -154,6 +154,113 @@ impl Cea608 {
Self::DeleteToEndOfRow(chan) => *chan,
}
}

/// Convert into one or two [`Code`] values.
pub fn into_code(&self, field: Field) -> [Code; 2] {
match self {
Self::Text(text) => {
let mut ret = [Code::NUL, Code::NUL];
if let Some(char1) = text.char1 {
ret[0] = Code::from_char(char1, text.channel).unwrap();
}
if let Some(char2) = text.char2 {
ret[1] = Code::from_char(char2, text.channel).unwrap();
}
ret
}
Self::NewMode(chan, mode) => [
Code::Control(tables::ControlCode {
field: Some(field),
channel: *chan,
control: match mode {
Mode::RollUp2 => tables::Control::RollUp2,
Mode::RollUp3 => tables::Control::RollUp3,
Mode::RollUp4 => tables::Control::RollUp4,
Mode::PaintOn => tables::Control::ResumeDirectionCaptioning,
Mode::PopOn => tables::Control::ResumeCaptionLoading,
},
}),
Code::NUL,
],
Self::EraseDisplay(chan) => [
Code::Control(tables::ControlCode {
field: Some(field),
channel: *chan,
control: tables::Control::EraseDisplayedMemory,
}),
Code::NUL,
],
Self::EraseNonDisplay(chan) => [
Code::Control(tables::ControlCode {
field: Some(field),
channel: *chan,
control: tables::Control::EraseNonDisplayedMemory,
}),
Code::NUL,
],
Self::CarriageReturn(chan) => [
Code::Control(tables::ControlCode {
field: Some(field),
channel: *chan,
control: tables::Control::CarriageReturn,
}),
Code::NUL,
],
Self::Backspace(chan) => [
Code::Control(tables::ControlCode {
field: Some(field),
channel: *chan,
control: tables::Control::Backspace,
}),
Code::NUL,
],
Self::EndOfCaption(chan) => [
Code::Control(tables::ControlCode {
field: Some(field),
channel: *chan,
control: tables::Control::EndOfCaption,
}),
Code::NUL,
],
Self::TabOffset(chan, count) => [
Code::Control(tables::ControlCode {
field: Some(field),
channel: *chan,
control: match count {
1 => tables::Control::TabOffset1,
2 => tables::Control::TabOffset2,
3 => tables::Control::TabOffset3,
_ => unreachable!(),
},
}),
Code::NUL,
],
Self::Preamble(chan, preamble) => [
Code::Control(tables::ControlCode {
field: Some(field),
channel: *chan,
control: tables::Control::PreambleAddress(*preamble),
}),
Code::NUL,
],
Self::MidRowChange(chan, midrow) => [
Code::Control(tables::ControlCode {
field: Some(field),
channel: *chan,
control: tables::Control::MidRow(*midrow),
}),
Code::NUL,
],
Self::DeleteToEndOfRow(chan) => [
Code::Control(tables::ControlCode {
field: Some(field),
channel: *chan,
control: tables::Control::DeleteToEndOfRow,
}),
Code::NUL,
],
}
}
}

/// Helper struct that has two purposes:
Expand Down Expand Up @@ -181,6 +288,7 @@ impl Cea608State {
}
}
self.last_data = Some(data);
trace!("decoded into codes {code:x?}");

// TODO: handle xds and text mode

Expand Down Expand Up @@ -269,6 +377,9 @@ pub struct Cea608Writer {
impl Cea608Writer {
/// Push a [`Code`] into this writer
pub fn push(&mut self, code: Code) {
if code == Code::NUL {
return;
}
self.pending.push_front(code)
}

Expand All @@ -278,43 +389,51 @@ impl Cea608Writer {
let mut prev = None::<Code>;

if let Some(code) = self.pending_code.take() {
trace!("returning pending code {code:?}");
code.write_into(&mut ret);
return ret;
}

while let Some(code) = self.pending.pop_back() {
if let Some(prev) = prev {
trace!("have prev {prev:?}");
if code.byte_len() == 1 {
let mut data = [0; 2];
prev.write_into(&mut ret);
code.write_into(&mut data);
ret[1] = data[0];
trace!("have 1 byte code {code:?}, returning {ret:x?}");
return ret;
} else if code.needs_backspace() {
self.pending_code = Some(code);
let mut data = [0; 2];
prev.write_into(&mut ret);
Code::Space.write_into(&mut data);
ret[1] = data[0];
trace!("have backspace needing code {code:?} stored as pending, pushing space with previous code {prev:?}");
return ret;
} else {
self.pending_code = Some(code);
prev.write_into(&mut ret);
trace!("have two byte code {code:?} stored as pending, pushing space");
return ret;
}
} else if code.needs_backspace() {
// all back space needing codes are 2 byte commands
self.pending_code = Some(code);
Code::Space.write_into(&mut ret);
trace!("have backspace needing code {code:?} stored as pending, pushing space");
return ret;
} else if code.byte_len() == 1 {
prev = Some(code);
} else {
trace!("have standalone 2 byte code {code:?}");
code.write_into(&mut ret);
return ret;
}
}
if let Some(prev) = prev {
trace!("have no more pending codes, writing prev {prev:?}");
prev.write_into(&mut ret);
}
ret
Expand Down Expand Up @@ -553,6 +672,105 @@ mod test {
assert_eq!(writer.pop(), [0x91, 0x31]);
assert_eq!(writer.pop(), [0x80, 0x80]);
}

#[test]
fn state_into_writer() {
test_init_log();
let stream = [[0x20, 0x80], [0x13, 0x2f], [0x80, 0x80]];
let mut state = Cea608State::default();
let mut writer = Cea608Writer::default();
for pair in stream {
let Some(cea608) = state.decode(pair).unwrap() else {
continue;
};
for code in cea608.into_code(Field::ONE) {
writer.push(code);
}
}
assert_eq!(writer.pop(), [0x20, 0x80]);
assert_eq!(writer.pop(), [0x13, 0x2f]);
assert_eq!(writer.pop(), [0x80, 0x80]);
}

#[test]
fn cea608_to_from_code() {
test_init_log();

let controls = [
tables::Control::ResumeCaptionLoading,
tables::Control::RollUp2,
tables::Control::RollUp3,
tables::Control::RollUp4,
tables::Control::EndOfCaption,
tables::Control::ResumeDirectionCaptioning,
tables::Control::tab_offset(1).unwrap(),
tables::Control::tab_offset(2).unwrap(),
tables::Control::tab_offset(3).unwrap(),
tables::Control::PreambleAddress(PreambleAddressCode::new(
3,
true,
tables::PreambleType::Indent4,
)),
tables::Control::EraseDisplayedMemory,
tables::Control::EraseNonDisplayedMemory,
tables::Control::CarriageReturn,
tables::Control::Backspace,
tables::Control::DeleteToEndOfRow,
];
let controls_with_preceding_overwritten_char = [tables::Control::MidRow(
MidRow::new_color(tables::Color::Green, true),
)];

let codes = [Code::PercentSign, Code::LatinLowerA];

let mut writer = Cea608Writer::default();

let mut state = Cea608State::default();

for field in [Field::ONE, Field::TWO] {
for channel in [Channel::ONE, Channel::TWO] {
for control in controls {
let code = Code::Control(ControlCode {
field: Some(field),
channel,
control,
});
writer.push(code);
let cea608 = state.decode(writer.pop()).unwrap().unwrap();
assert_eq!(cea608.into_code(field)[0], code);
}
for control in controls_with_preceding_overwritten_char {
let code = Code::Control(ControlCode {
field: Some(field),
channel,
control,
});
writer.push(code);
writer.pop(); // eat the preceding char
let cea608 = state.decode(writer.pop()).unwrap().unwrap();
assert_eq!(cea608.into_code(field)[0], code);
}
}
}

for code in codes {
debug!("pushing {code:?}");
writer.push(code);
let data = writer.pop();
let cea608 = state.decode(data).unwrap().unwrap();
assert_eq!(cea608.into_code(Field::ONE)[0], code);
}
}

#[test]
fn writer_ignore_padding() {
test_init_log();

let mut writer = Cea608Writer::default();
writer.push(Code::NUL);
writer.push(Code::LatinLowerA);
assert_eq!(writer.pop(), [0x61, 0x80]);
}
}

#[cfg(test)]
Expand Down
4 changes: 2 additions & 2 deletions src/tables.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -442,8 +442,8 @@ impl Control {
pub fn tab_offset(offset: u8) -> Option<Control> {
match offset {
1 => Some(Control::TabOffset1),
2 => Some(Control::TabOffset1),
3 => Some(Control::TabOffset1),
2 => Some(Control::TabOffset2),
3 => Some(Control::TabOffset3),
_ => None,
}
}
Expand Down
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