swf: Number enum FontThickness

swf/src/read.rs

@@ -1164,12 +1164,8 @@ impl<'a> Reader<'a> {
 
     fn read_define_font_align_zones(&mut self) -> Result<Tag<'a>> {
         let id = self.read_character_id()?;
-        let thickness = match self.read_u8()? {
-            0b00_000000 => FontThickness::Thin,
-            0b01_000000 => FontThickness::Medium,
-            0b10_000000 => FontThickness::Thick,
-            _ => return Err(Error::invalid_data("Invalid font thickness type.")),
-        };
+        let thickness = FontThickness::from_u8(self.read_u8()? >> 6)
+            .ok_or_else(|| Error::invalid_data("Invalid font thickness type."))?;
         let mut zones = vec![];
         while let Ok(zone) = self.read_font_align_zone() {
             zones.push(zone);

swf/src/types.rs

@@ -1398,11 +1398,21 @@ pub struct FontAlignZone {
     pub height: i16,
 }
 
-#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+#[derive(Clone, Copy, Debug, PartialEq, Eq, FromPrimitive, ToPrimitive)]
 pub enum FontThickness {
-    Thin,
-    Medium,
-    Thick,
+    Thin = 0,
+    Medium = 1,
+    Thick = 2,
+}
+
+impl FontThickness {
+    pub fn from_u8(n: u8) -> Option<Self> {
+        num_traits::FromPrimitive::from_u8(n)
+    }
+
+    pub fn to_u8(self) -> u8 {
+        num_traits::ToPrimitive::to_u8(&self).unwrap()
+    }
 }
 
 #[derive(Clone, Debug, PartialEq)]

swf/src/write.rs

@@ -685,11 +685,7 @@ impl<W: Write> Writer<W> {
             } => {
                 self.write_tag_header(TagCode::DefineFontAlignZones, 3 + 10 * zones.len() as u32)?;
                 self.write_character_id(id)?;
-                self.write_u8(match thickness {
-                    FontThickness::Thin => 0b00_000000,
-                    FontThickness::Medium => 0b01_000000,
-                    FontThickness::Thick => 0b10_000000,
-                })?;
+                self.write_u8(thickness.to_u8() << 6)?;
                 for zone in zones {
                     self.write_u8(2)?; // Always 2 dimensions.
                     self.write_i16(zone.left)?;