Script opcode and data support

Overrides the shift-left operator for pushing opcodes onto the Script,
matching the notation used in zcashd.

zcash_primitives/src/legacy.rs

@@ -0,0 +1,105 @@
+//! Support for legacy transparent addresses and scripts.
+
+use byteorder::{ReadBytesExt, WriteBytesExt};
+use std::io::{self, Read, Write};
+use std::ops::Shl;
+
+use crate::serialize::Vector;
+
+/// Script opcodes.
+enum OpCode {
+    // push value
+    PushData1 = 0x4c,
+    PushData2 = 0x4d,
+    PushData4 = 0x4e,
+}
+
+/// A serialized script, used inside transparent inputs and outputs of a transaction.
+#[derive(Debug, Default)]
+pub struct Script(pub Vec<u8>);
+
+impl Script {
+    pub fn read<R: Read>(mut reader: R) -> io::Result<Self> {
+        let script = Vector::read(&mut reader, |r| r.read_u8())?;
+        Ok(Script(script))
+    }
+
+    pub fn write<W: Write>(&self, mut writer: W) -> io::Result<()> {
+        Vector::write(&mut writer, &self.0, |w, e| w.write_u8(*e))
+    }
+}
+
+impl Shl<OpCode> for Script {
+    type Output = Self;
+
+    fn shl(mut self, rhs: OpCode) -> Self {
+        self.0.push(rhs as u8);
+        self
+    }
+}
+
+impl Shl<&[u8]> for Script {
+    type Output = Self;
+
+    fn shl(mut self, data: &[u8]) -> Self {
+        if data.len() < OpCode::PushData1 as usize {
+            self.0.push(data.len() as u8);
+        } else if data.len() <= 0xff {
+            self.0.push(OpCode::PushData1 as u8);
+            self.0.push(data.len() as u8);
+        } else if data.len() <= 0xffff {
+            self.0.push(OpCode::PushData2 as u8);
+            self.0.extend(&(data.len() as u16).to_le_bytes());
+        } else {
+            self.0.push(OpCode::PushData4 as u8);
+            self.0.extend(&(data.len() as u32).to_le_bytes());
+        }
+        self.0.extend(data);
+        self
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::{OpCode, Script};
+
+    #[test]
+    fn script_opcode() {
+        {
+            let script = Script::default() << OpCode::PushData1;
+            assert_eq!(&script.0, &[OpCode::PushData1 as u8]);
+        }
+    }
+
+    #[test]
+    fn script_pushdata() {
+        {
+            let script = Script::default() << &[1, 2, 3, 4][..];
+            assert_eq!(&script.0, &[4, 1, 2, 3, 4]);
+        }
+
+        {
+            let short_data = vec![2; 100];
+            let script = Script::default() << &short_data[..];
+            assert_eq!(script.0[0], OpCode::PushData1 as u8);
+            assert_eq!(script.0[1] as usize, 100);
+            assert_eq!(&script.0[2..], &short_data[..]);
+        }
+
+        {
+            let medium_data = vec![7; 1024];
+            let script = Script::default() << &medium_data[..];
+            assert_eq!(script.0[0], OpCode::PushData2 as u8);
+            assert_eq!(&script.0[1..3], &[0x00, 0x04][..]);
+            assert_eq!(&script.0[3..], &medium_data[..]);
+        }
+
+        {
+            let long_data = vec![42; 1_000_000];
+            let script = Script::default() << &long_data[..];
+            assert_eq!(script.0[0], OpCode::PushData4 as u8);
+            assert_eq!(&script.0[1..5], &[0x40, 0x42, 0x0f, 0x00][..]);
+            assert_eq!(&script.0[5..], &long_data[..]);
+        }
+    }
+}

zcash_primitives/src/lib.rs

@@ -19,6 +19,7 @@ use sapling_crypto::jubjub::JubjubBls12;
 
 pub mod block;
 pub mod keys;
+pub mod legacy;
 pub mod merkle_tree;
 pub mod note_encryption;
 pub mod prover;

zcash_primitives/src/transaction/components.rs

@@ -7,7 +7,7 @@ use sapling_crypto::{
 };
 use std::io::{self, Read, Write};
 
-use serialize::Vector;
+use legacy::Script;
 use JUBJUB;
 
 // π_A + π_B + π_C
@@ -58,20 +58,6 @@ impl Amount {
     }
 }
 
-#[derive(Debug)]
-pub struct Script(pub Vec<u8>);
-
-impl Script {
-    pub fn read<R: Read>(mut reader: R) -> io::Result<Self> {
-        let script = Vector::read(&mut reader, |r| r.read_u8())?;
-        Ok(Script(script))
-    }
-
-    pub fn write<W: Write>(&self, mut writer: W) -> io::Result<()> {
-        Vector::write(&mut writer, &self.0, |w, e| w.write_u8(*e))
-    }
-}
-
 #[derive(Debug)]
 pub struct OutPoint {
     hash: [u8; 32],

zcash_primitives/src/transaction/sighash.rs

@@ -3,10 +3,11 @@ use byteorder::{LittleEndian, WriteBytesExt};
 use ff::{PrimeField, PrimeFieldRepr};
 
 use super::{
-    components::{Amount, Script, TxOut},
+    components::{Amount, TxOut},
     Transaction, TransactionData, OVERWINTER_VERSION_GROUP_ID, SAPLING_TX_VERSION,
     SAPLING_VERSION_GROUP_ID,
 };
+use legacy::Script;
 
 const ZCASH_SIGHASH_PERSONALIZATION_PREFIX: &'static [u8; 12] = b"ZcashSigHash";
 const ZCASH_PREVOUTS_HASH_PERSONALIZATION: &'static [u8; 16] = b"ZcashPrevoutHash";

zcash_primitives/src/transaction/tests.rs

@@ -6,11 +6,8 @@ use sapling_crypto::{
     redjubjub::PrivateKey,
 };
 
-use super::{
-    components::{Amount, Script},
-    sighash::signature_hash,
-    Transaction, TransactionData,
-};
+use super::{components::Amount, sighash::signature_hash, Transaction, TransactionData};
+use legacy::Script;
 use JUBJUB;
 
 #[test]