Add SCP control support

Modern usage of this control function comes from the BiDi draft
proposal:

https://terminal-wg.pages.freedesktop.org/bidi/recommendation/escape-sequences.html

The draft slightly extends the definition in ECMA-48.

Signed-off-by: Mohammad AlSaleh <CE.Mohammad.AlSaleh@gmail.com>

1 files changed, 53 insertions, 0 deletions

diff --git a/src/ansi.rs b/src/ansi.rs
index e5011e9..59b17e6 100644
--- a/src/ansi.rs
+++ b/src/ansi.rs
@@ -677,6 +677,9 @@ pub trait Handler {
     ///
     /// The output is of form `CSI > 4 ; mode m`.
     fn report_modify_other_keys(&mut self) {}
+
+    // Set SCP control.
+    fn set_scp(&mut self, _char_path: ScpCharPath, _update_mode: ScpUpdateMode) {}
 }
 
 bitflags! {
@@ -1195,6 +1198,32 @@ impl StandardCharset {
     }
 }
 
+/// SCP control's first parameter which determines character path.
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+pub enum ScpCharPath {
+    /// SCP's first parameter value of 0. Behavior is implementation defined.
+    Default,
+    /// SCP's first parameter value of 1 which sets character path to LEFT-TO-RIGHT.
+    LTR,
+    /// SCP's first parameter value of 2 which sets character path to RIGHT-TO-LEFT.
+    RTL,
+}
+
+/// SCP control's second parameter which determines update mode/direction between components.
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+pub enum ScpUpdateMode {
+    /// SCP's second parameter value of 0 (the default). Implementation dependant update.
+    ImplementationDependant,
+    /// SCP's second parameter value of 1.
+    ///
+    /// Reflect data component changes in the presentation component.
+    DataToPresentation,
+    /// SCP's second parameter value of 2.
+    ///
+    /// Reflect presentation component changes in the data component.
+    PresentationToData,
+}
+
 impl<'a, H, T> crate::Perform for Performer<'a, H, T>
 where
     H: Handler + 'a,
@@ -1551,6 +1580,30 @@ where
 
                 handler.clear_line(mode);
             },
+            ('k', [b' ']) => {
+                // SCP control.
+                let char_path = match next_param_or(0) {
+                    0 => ScpCharPath::Default,
+                    1 => ScpCharPath::LTR,
+                    2 => ScpCharPath::RTL,
+                    _ => {
+                        unhandled!();
+                        return;
+                    },
+                };
+
+                let update_mode = match next_param_or(0) {
+                    0 => ScpUpdateMode::ImplementationDependant,
+                    1 => ScpUpdateMode::DataToPresentation,
+                    2 => ScpUpdateMode::PresentationToData,
+                    _ => {
+                        unhandled!();
+                        return;
+                    },
+                };
+
+                handler.set_scp(char_path, update_mode);
+            },
             ('L', []) => handler.insert_blank_lines(next_param_or(1) as usize),
             ('l', []) => {
                 for param in params_iter.map(|param| param[0]) {