swf: Extract `Opcode::format` and `TagCode::format`

swf/src/avm1/opcode.rs

@@ -1,4 +1,3 @@
-#[allow(dead_code, clippy::useless_attribute)]
 #[derive(Debug, PartialEq, Clone, Copy, FromPrimitive)]
 pub enum OpCode {
     End = 0x00,
@@ -116,3 +115,17 @@ pub enum OpCode {
     Call = 0x9E,
     GotoFrame2 = 0x9F,
 }
+
+impl OpCode {
+    pub fn from_u8(n: u8) -> Option<Self> {
+        num_traits::FromPrimitive::from_u8(n)
+    }
+
+    pub fn format(opcode: u8) -> String {
+        if let Some(op) = Self::from_u8(opcode) {
+            format!("{:?}", op)
+        } else {
+            format!("Unknown({})", opcode)
+        }
+    }
+}

swf/src/avm1/read.rs

@@ -87,7 +87,6 @@ impl<'a> Reader<'a> {
     /// The final `length` returned will be total length of the action, including sub-blocks.
     #[inline]
     fn read_op(&mut self, opcode: u8, length: &mut usize) -> Result<Option<Action<'a>>> {
-        use num_traits::FromPrimitive;
         let action = if let Some(op) = OpCode::from_u8(opcode) {
             match op {
                 OpCode::End => return Ok(None),

swf/src/error.rs

@@ -1,3 +1,4 @@
+use crate::avm1::opcode::OpCode;
 use crate::tag_code::TagCode;
 use std::{borrow, error, fmt, io};
 
@@ -73,30 +74,21 @@ impl Error {
 
 impl fmt::Display for Error {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        use crate::num_traits::FromPrimitive;
         match self {
             Self::Avm1ParseError { opcode, source } => {
-                let op = crate::avm1::opcode::OpCode::from_u8(*opcode);
-                "Error parsing AVM1 action ".fmt(f)?;
-                if let Some(op) = op {
-                    write!(f, "{:?}", op)?;
-                } else {
-                    write!(f, "Unknown({})", opcode)?;
-                };
+                write!(f, "Error parsing AVM1 action {}", OpCode::format(*opcode))?;
                 if let Some(source) = source {
                     write!(f, ": {}", source)?;
                 }
                 Ok(())
             }
             Self::SwfParseError { tag_code, source } => {
-                "Error parsing SWF tag ".fmt(f)?;
-                if let Some(tag_code) = TagCode::from_u16(*tag_code) {
-                    write!(f, "{:?}", tag_code)?;
-                } else {
-                    write!(f, "Unknown({})", tag_code)?;
-                };
-                write!(f, ": {}", source)?;
-                Ok(())
+                write!(
+                    f,
+                    "Error parsing SWF tag {}: {}",
+                    TagCode::format(*tag_code),
+                    source
+                )
             }
             Self::IoError(e) => e.fmt(f),
             Self::InvalidData(message) => write!(f, "Invalid data: {}", message),

swf/src/tag_code.rs

@@ -1,6 +1,3 @@
-#![allow(clippy::useless_attribute)]
-
-#[allow(dead_code)]
 #[derive(Debug, PartialEq, Clone, Copy, FromPrimitive)]
 pub enum TagCode {
     End = 0,
@@ -95,4 +92,12 @@ impl TagCode {
     pub fn from_u16(n: u16) -> Option<Self> {
         num_traits::FromPrimitive::from_u16(n)
     }
+
+    pub fn format(tag_code: u16) -> String {
+        if let Some(tag_code) = TagCode::from_u16(tag_code) {
+            format!("{:?}", tag_code)
+        } else {
+            format!("Unknown({})", tag_code)
+        }
+    }
 }