Merge pull request rust-bitcoin#569 from stevenroose/static-asm

Make Script::fmt_asm a static method and add Script::str_asm

src/blockdata/script.rs

@@ -43,6 +43,12 @@ use util::key::PublicKey;
 /// A Bitcoin script
 pub struct Script(Box<[u8]>);
 
+impl AsRef<[u8]> for Script {
+    fn as_ref(&self) -> &[u8] {
+        &self.0
+    }
+}
+
 impl fmt::Debug for Script {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         f.write_str("Script(")?;
@@ -452,43 +458,43 @@ impl Script {
         Ok(bitcoinconsensus::verify (&self.0[..], amount, spending, index)?)
     }
 
-    /// Write the assembly decoding of the script to the formatter.
-    pub fn fmt_asm(&self, f: &mut dyn fmt::Write) -> fmt::Result {
+    /// Write the assembly decoding of the script bytes to the formatter.
+    pub fn bytes_to_asm_fmt(script: &[u8], f: &mut dyn fmt::Write) -> fmt::Result {
         let mut index = 0;
-        while index < self.0.len() {
-            let opcode = opcodes::All::from(self.0[index]);
+        while index < script.len() {
+            let opcode = opcodes::All::from(script[index]);
             index += 1;
 
             let data_len = if let opcodes::Class::PushBytes(n) = opcode.classify() {
                 n as usize
             } else {
                 match opcode {
                     opcodes::all::OP_PUSHDATA1 => {
-                        if self.0.len() < index + 1 {
+                        if script.len() < index + 1 {
                             f.write_str("<unexpected end>")?;
                             break;
                         }
-                        match read_uint(&self.0[index..], 1) {
+                        match read_uint(&script[index..], 1) {
                             Ok(n) => { index += 1; n as usize }
                             Err(_) => { f.write_str("<bad length>")?; break; }
                         }
                     }
                     opcodes::all::OP_PUSHDATA2 => {
-                        if self.0.len() < index + 2 {
+                        if script.len() < index + 2 {
                             f.write_str("<unexpected end>")?;
                             break;
                         }
-                        match read_uint(&self.0[index..], 2) {
+                        match read_uint(&script[index..], 2) {
                             Ok(n) => { index += 2; n as usize }
                             Err(_) => { f.write_str("<bad length>")?; break; }
                         }
                     }
                     opcodes::all::OP_PUSHDATA4 => {
-                        if self.0.len() < index + 4 {
+                        if script.len() < index + 4 {
                             f.write_str("<unexpected end>")?;
                             break;
                         }
-                        match read_uint(&self.0[index..], 4) {
+                        match read_uint(&script[index..], 4) {
                             Ok(n) => { index += 4; n as usize }
                             Err(_) => { f.write_str("<bad length>")?; break; }
                         }
@@ -507,8 +513,8 @@ impl Script {
             // Write any pushdata
             if data_len > 0 {
                 f.write_str(" ")?;
-                if index + data_len <= self.0.len() {
-                    for ch in &self.0[index..index + data_len] {
+                if index + data_len <= script.len() {
+                    for ch in &script[index..index + data_len] {
                             write!(f, "{:02x}", ch)?;
                     }
                     index += data_len;
@@ -521,12 +527,22 @@ impl Script {
         Ok(())
     }
 
-    /// Get the assembly decoding of the script.
-    pub fn asm(&self) -> String {
+    /// Write the assembly decoding of the script to the formatter.
+    pub fn fmt_asm(&self, f: &mut dyn fmt::Write) -> fmt::Result {
+        Script::bytes_to_asm_fmt(self.as_ref(), f)
+    }
+
+    /// Create an assembly decoding of the script in the given byte slice.
+    pub fn bytes_to_asm(script: &[u8]) -> String {
         let mut buf = String::new();
-        self.fmt_asm(&mut buf).unwrap();
+        Script::bytes_to_asm_fmt(script, &mut buf).unwrap();
         buf
     }
+
+    /// Get the assembly decoding of the script.
+    pub fn asm(&self) -> String {
+        Script::bytes_to_asm(self.as_ref())
+    }
 }
 
 /// Creates a new script from an existing vector