swf: Introduce ShapeRecordFlag

No functionality change.
ruffle-rs · May 2, 2023 · 182ae6c · 182ae6c
1 parent fe56f8d
commit 182ae6c
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Showing 3 changed files with 67 additions and 33 deletions.
diff --git a/swf/src/read.rs b/swf/src/read.rs
@@ -1762,49 +1762,58 @@ impl<'a> Reader<'a> {
                 })
             }
         } else {
-            let flags = bits.read_ubits(5)?;
-            if flags != 0 {
+            let flags = ShapeRecordFlag::from_bits_truncate(bits.read_ubits(5)? as u8);
+            if !flags.is_empty() {
                 // StyleChange
                 let num_fill_bits = context.num_fill_bits as u32;
                 let num_line_bits = context.num_line_bits as u32;
-                let mut new_style = StyleChangeData {
-                    move_to: None,
-                    fill_style_0: None,
-                    fill_style_1: None,
-                    line_style: None,
-                    new_styles: None,
-                };
-                if (flags & 0b1) != 0 {
-                    // move
+                let move_to = if flags.contains(ShapeRecordFlag::MOVE_TO) {
                     let num_bits = bits.read_ubits(5)?;
-                    new_style.move_to = Some((
+                    Some((
                         bits.read_sbits_twips(num_bits)?,
                         bits.read_sbits_twips(num_bits)?,
-                    ));
-                }
-                if (flags & 0b10) != 0 {
-                    new_style.fill_style_0 = Some(bits.read_ubits(num_fill_bits)?);
-                }
-                if (flags & 0b100) != 0 {
-                    new_style.fill_style_1 = Some(bits.read_ubits(num_fill_bits)?);
-                }
-                if (flags & 0b1000) != 0 {
-                    new_style.line_style = Some(bits.read_ubits(num_line_bits)?);
-                }
+                    ))
+                } else {
+                    None
+                };
+                let fill_style_0 = if flags.contains(ShapeRecordFlag::FILL_STYLE_0) {
+                    Some(bits.read_ubits(num_fill_bits)?)
+                } else {
+                    None
+                };
+                let fill_style_1 = if flags.contains(ShapeRecordFlag::FILL_STYLE_1) {
+                    Some(bits.read_ubits(num_fill_bits)?)
+                } else {
+                    None
+                };
+                let line_style = if flags.contains(ShapeRecordFlag::LINE_STYLE) {
+                    Some(bits.read_ubits(num_line_bits)?)
+                } else {
+                    None
+                };
                 // The spec says that StyleChangeRecord can only occur in DefineShape2+,
                 // but SWFs in the wild exist with them in DefineShape1 (generated by third party tools),
                 // and these run correctly in the Flash Player.
-                if (flags & 0b10000) != 0 {
+                let new_styles = if flags.contains(ShapeRecordFlag::NEW_STYLES) {
                     let mut reader = Reader::new(bits.reader(), context.swf_version);
                     let (new_styles, num_fill_bits, num_line_bits) =
                         reader.read_shape_styles(context.shape_version)?;
+                    *bits.reader() = reader.input;
                     context.num_fill_bits = num_fill_bits;
                     context.num_line_bits = num_line_bits;
-                    new_style.new_styles = Some(new_styles);
-                    *bits.reader() = reader.input;
-                }
-                Some(ShapeRecord::StyleChange(Box::new(new_style)))
+                    Some(new_styles)
+                } else {
+                    None
+                };
+                Some(ShapeRecord::StyleChange(Box::new(StyleChangeData {
+                    move_to,
+                    fill_style_0,
+                    fill_style_1,
+                    line_style,
+                    new_styles,
+                })))
             } else {
+                // EndShapeRecord
                 None
             }
         };

diff --git a/swf/src/types.rs b/swf/src/types.rs
@@ -715,6 +715,17 @@ pub enum ShapeRecord {
     },
 }
 
+bitflags! {
+    #[derive(Clone, Copy, Debug, Eq, PartialEq)]
+    pub struct ShapeRecordFlag: u8 {
+        const MOVE_TO      = 1 << 0;
+        const FILL_STYLE_0 = 1 << 1;
+        const FILL_STYLE_1 = 1 << 2;
+        const LINE_STYLE   = 1 << 3;
+        const NEW_STYLES   = 1 << 4;
+    }
+}
+
 #[derive(Clone, Debug, Eq, PartialEq)]
 pub struct StyleChangeData {
     pub move_to: Option<(Twips, Twips)>,

diff --git a/swf/src/write.rs b/swf/src/write.rs
@@ -1460,11 +1460,25 @@ impl<W: Write> Writer<W> {
                 bits.write_bit(false)?; // Style change
                 let num_fill_bits = context.num_fill_bits.into();
                 let num_line_bits = context.num_line_bits.into();
-                bits.write_bit(style_change.new_styles.is_some())?;
-                bits.write_bit(style_change.line_style.is_some())?;
-                bits.write_bit(style_change.fill_style_1.is_some())?;
-                bits.write_bit(style_change.fill_style_0.is_some())?;
-                bits.write_bit(style_change.move_to.is_some())?;
+                let mut flags = ShapeRecordFlag::empty();
+                flags.set(ShapeRecordFlag::MOVE_TO, style_change.move_to.is_some());
+                flags.set(
+                    ShapeRecordFlag::FILL_STYLE_0,
+                    style_change.fill_style_0.is_some(),
+                );
+                flags.set(
+                    ShapeRecordFlag::FILL_STYLE_1,
+                    style_change.fill_style_1.is_some(),
+                );
+                flags.set(
+                    ShapeRecordFlag::LINE_STYLE,
+                    style_change.line_style.is_some(),
+                );
+                flags.set(
+                    ShapeRecordFlag::NEW_STYLES,
+                    style_change.new_styles.is_some(),
+                );
+                bits.write_ubits(5, flags.bits().into())?;
                 if let Some((move_x, move_y)) = style_change.move_to {
                     let num_bits = max(count_sbits_twips(move_x), count_sbits_twips(move_y));
                     bits.write_ubits(5, num_bits)?;