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feat(tariscript)!: use varints in tari script (de)serialization (#4460)
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Description
---
Use varint for op codes that use 64bit numbers but in general will be low.

Motivation and Context
---
#4108

How Has This Been Tested?
---
Unit tests.
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Cifko committed Aug 17, 2022
1 parent ca604c2 commit a0403e5
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Showing 3 changed files with 26 additions and 77 deletions.
1 change: 1 addition & 0 deletions Cargo.lock

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1 change: 1 addition & 0 deletions infrastructure/tari_script/Cargo.toml
Expand Up @@ -18,6 +18,7 @@ tari_utilities = { git = "https://github.com/tari-project/tari_utilities.git", t

blake2 = "0.9"
digest = "0.9.0"
integer-encoding = "3.0.2"
serde = "1.0.136"
sha2 = "0.9"
sha3 = "0.9"
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101 changes: 24 additions & 77 deletions infrastructure/tari_script/src/op_codes.rs
Expand Up @@ -17,6 +17,7 @@

use std::{fmt, ops::Deref};

use integer_encoding::VarInt;
use tari_crypto::ristretto::RistrettoPublicKey;
use tari_utilities::{hex::Hex, ByteArray, ByteArrayError};

Expand Down Expand Up @@ -76,28 +77,6 @@ pub fn slice_to_vec_pubkeys(slice: &[u8], num: usize) -> Result<Vec<RistrettoPub
Ok(public_keys)
}

/// Convert a slice of little endian bytes into a u64.
///
/// # Panics
///
/// The function does not check slice for length at all. You need to check this / guarantee it yourself.
fn slice_to_u64(slice: &[u8]) -> u64 {
let mut num = [0u8; 8];
num.copy_from_slice(slice);
u64::from_le_bytes(num)
}

/// Convert a slice of little endian bytes into an i64.
///
/// # Panics
///
/// The function does not check slice for length at all. You need to check this / guarantee it yourself.
fn slice_to_i64(slice: &[u8]) -> i64 {
let mut num = [0u8; 8];
num.copy_from_slice(slice);
i64::from_le_bytes(num)
}

// Opcode constants: Block Height Checks
pub const OP_CHECK_HEIGHT_VERIFY: u8 = 0x66;
pub const OP_CHECK_HEIGHT: u8 = 0x67;
Expand Down Expand Up @@ -291,18 +270,12 @@ impl Opcode {
use Opcode::*;
match *code {
OP_CHECK_HEIGHT_VERIFY => {
if bytes.len() < 9 {
return Err(ScriptError::InvalidData);
}
let height = slice_to_u64(&bytes[1..9]);
Ok((CheckHeightVerify(height), &bytes[9..]))
let (height, size) = u64::decode_var(&bytes[1..]).ok_or(ScriptError::InvalidData)?;
Ok((CheckHeightVerify(height), &bytes[size + 1..]))
},
OP_CHECK_HEIGHT => {
if bytes.len() < 9 {
return Err(ScriptError::InvalidData);
}
let height = slice_to_u64(&bytes[1..9]);
Ok((CheckHeight(height), &bytes[9..]))
let (height, size) = u64::decode_var(&bytes[1..]).ok_or(ScriptError::InvalidData)?;
Ok((CheckHeight(height), &bytes[size + 1..]))
},
OP_COMPARE_HEIGHT_VERIFY => Ok((CompareHeightVerify, &bytes[1..])),
OP_COMPARE_HEIGHT => Ok((CompareHeight, &bytes[1..])),
Expand All @@ -317,11 +290,8 @@ impl Opcode {
Ok((PushHash(hash), &bytes[33..]))
},
OP_PUSH_INT => {
if bytes.len() < 9 {
return Err(ScriptError::InvalidData);
}
let n = slice_to_i64(&bytes[1..9]);
Ok((PushInt(n), &bytes[9..]))
let (n, size) = i64::decode_var(&bytes[1..]).ok_or(ScriptError::InvalidData)?;
Ok((PushInt(n), &bytes[size + 1..]))
},
OP_PUSH_PUBKEY => {
if bytes.len() < 33 {
Expand Down Expand Up @@ -415,11 +385,15 @@ impl Opcode {
match self {
CheckHeightVerify(height) => {
array.push(OP_CHECK_HEIGHT_VERIFY);
array.extend_from_slice(&height.to_le_bytes());
let mut buf = [0u8; 10];
let used = height.encode_var(&mut buf[..]);
array.extend_from_slice(&buf[0..used]);
},
CheckHeight(height) => {
array.push(OP_CHECK_HEIGHT);
array.extend_from_slice(&height.to_le_bytes());
let mut buf = [0u8; 10];
let used = height.encode_var(&mut buf[..]);
array.extend_from_slice(&buf[0..used]);
},
CompareHeightVerify => array.push(OP_COMPARE_HEIGHT_VERIFY),
CompareHeight => array.push(OP_COMPARE_HEIGHT),
Expand All @@ -432,7 +406,9 @@ impl Opcode {
},
PushInt(n) => {
array.push(OP_PUSH_INT);
array.extend_from_slice(&n.to_le_bytes());
let mut buf = [0u8; 10];
let used = n.encode_var(&mut buf[..]);
array.extend_from_slice(&buf[0..used]);
},
PushPubKey(p) => {
array.push(OP_PUSH_PUBKEY);
Expand Down Expand Up @@ -591,50 +567,19 @@ mod test {
assert!(b.is_empty());
}

#[test]
fn slice_to_u64_tests() {
// Zero
let val = slice_to_u64(&[0, 0, 0, 0, 0, 0, 0, 0]);
assert_eq!(val, 0);
// Little-endian one-byte
let val = slice_to_u64(&[63, 0, 0, 0, 0, 0, 0, 0]);
assert_eq!(val, 63);
// A large number
let val = slice_to_u64(&[0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0x7F]);
assert_eq!(val, 9_223_372_036_854_775_807);
}

#[test]
fn slice_to_i64_tests() {
// Zero
let val = slice_to_i64(&[0, 0, 0, 0, 0, 0, 0, 0]);
assert_eq!(val, 0);
// Little-endian one-byte
let val = slice_to_i64(&[63, 0, 0, 0, 0, 0, 0, 0]);
assert_eq!(val, 63);
let val = slice_to_i64(&[63, 0, 0, 0, 0, 0, 0, 128]);
assert_eq!(val, -9_223_372_036_854_775_745);
// A large negative number
let val = slice_to_i64(&[0x00, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0x80]);
assert_eq!(val, -9_151_314_442_816_848_128);
}

#[test]
fn check_height() {
fn test_check_height(op: &Opcode, val: u8, display: &str) {
// Serialize
assert!(matches!(
Opcode::read_next(&[val, 1, 2, 3]),
Err(ScriptError::InvalidData)
));
let s = &[val, 63, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3];
assert!(matches!(Opcode::read_next(&[val, 255]), Err(ScriptError::InvalidData)));
let s = &[val, 63, 1, 2, 3];
let (opcode, rem) = Opcode::read_next(s).unwrap();
assert_eq!(opcode, *op);
assert_eq!(rem, &[1, 2, 3]);
// Deserialise
let mut arr = vec![1, 2, 3];
op.to_bytes(&mut arr);
assert_eq!(&arr, &[1, 2, 3, val, 63, 0, 0, 0, 0, 0, 0, 0]);
assert_eq!(&arr, &[1, 2, 3, val, 63]);
// Format
assert_eq!(format!("{}", op).as_str(), display);
}
Expand All @@ -645,16 +590,18 @@ mod test {
#[test]
fn push_int() {
// Serialise
assert!(matches!(Opcode::read_next(b"\x7dshort"), Err(ScriptError::InvalidData)));
let s = &[OP_PUSH_INT, 1, 1, 0, 0, 0, 0, 0, 0];
assert!(matches!(Opcode::read_next(&[0x7d, 255]), Err(ScriptError::InvalidData)));
let s = &[OP_PUSH_INT, 130, 4];
let (opcode, rem) = Opcode::read_next(s).unwrap();
let mut arr = vec![];
Opcode::PushInt(257).to_bytes(&mut arr);
assert!(matches!(opcode, Opcode::PushInt(257)));
assert!(rem.is_empty());
// Deserialise
let op = Opcode::PushInt(257);
let mut arr = vec![];
op.to_bytes(&mut arr);
assert_eq!(&arr, &[OP_PUSH_INT, 1, 1, 0, 0, 0, 0, 0, 0]);
assert_eq!(&arr, &[OP_PUSH_INT, 130, 4]);
// Format
assert_eq!(format!("{}", op).as_str(), "PushInt(257)");
}
Expand Down

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