lazy block flags parsing

1 files changed, 29 insertions, 35 deletions

diff --git a/matroska/src/block.rs b/matroska/src/block.rs
index 51bea84..54d9de5 100644
--- a/matroska/src/block.rs
+++ b/matroska/src/block.rs
@@ -12,6 +12,7 @@ use std::io::{Cursor, Write};
 
 #[derive(Debug, PartialEq, Clone, Copy)]
 pub enum LacingType {
+    None,
     Xiph,
     FixedSize,
     Ebml,
@@ -20,39 +21,46 @@ pub enum LacingType {
 #[derive(Debug, PartialEq, Clone)]
 pub struct Block {
     pub track: u64,
-    pub keyframe: bool,
-    pub discardable: bool,
+    pub flags: Flags,
     pub timestamp_off: i16,
-    pub invisible: bool,
-    pub lacing: Option<LacingType>,
     pub data: Vec<u8>,
 }
 
+#[derive(Debug, PartialEq, Clone)]
+pub struct Flags(u8);
+
+impl Flags {
+    pub fn keyframe(&self) -> bool {
+        self.0 & 0b10000000 != 0
+    }
+    pub fn lacing(&self) -> LacingType {
+        match self.0 & 0b00000110 {
+            0b000 => LacingType::None,
+            0b010 => LacingType::Xiph,
+            0b100 => LacingType::FixedSize,
+            0b110 => LacingType::Ebml,
+            _ => unreachable!(),
+        }
+    }
+    pub fn discardable(&self) -> bool {
+        self.0 & 0b00000001 != 0
+    }
+    pub fn invisible(&self) -> bool {
+        self.0 & 0b00001000 != 0
+    }
+}
+
 impl ReadValue for Block {
     fn from_buf(buf: &[u8]) -> Result<Self> {
         let (track, c) = Cursor::new(buf).read_vint_len()?;
         let timestamp_off = i16::from_be_bytes(buf[c..c + 2].try_into().unwrap());
-        let flags = buf[c + 2];
+        let flags = Flags(buf[c + 2]);
         let data = Vec::from(&buf[c + 3..]);
 
-        let invisible = (flags & 0b1000) == 0b1000;
-        let lacing = match flags & 0b110 {
-            0b000 => None,
-            0b010 => Some(LacingType::Xiph),
-            0b100 => Some(LacingType::FixedSize),
-            0b110 => Some(LacingType::Ebml),
-            _ => unreachable!(),
-        };
-        let keyframe = (flags & 0b10000000) == 0b10000000;
-        let discardable = (flags & 0b1) == 0b1;
-
         Ok(Self {
-            keyframe,
-            discardable,
             track,
             data,
-            invisible,
-            lacing,
+            flags,
             timestamp_off,
         })
     }
@@ -63,21 +71,7 @@ impl WriteValue for Block {
         write_vint(w, self.inner_len() as u64)?;
         write_vint(w, self.track)?;
         w.write_all(&self.timestamp_off.to_be_bytes())?;
-        w.write_all(&[match self.discardable {
-            true => 0b1,
-            false => 0b0,
-        } | match self.keyframe {
-            true => 0b10000000,
-            false => 0b00000000,
-        } | match self.invisible {
-            true => 0b1000,
-            false => 0b0000,
-        } | match self.lacing {
-            Some(LacingType::Xiph) => 0b010,
-            Some(LacingType::Ebml) => 0b100,
-            Some(LacingType::FixedSize) => 0b110,
-            None => 0b0000,
-        }])?;
+        w.write_all(&[self.flags.0])?;
         w.write_all(&self.data)?;
         Ok(())
     }