Implements ToCanonicalJson for protocol parameters

pallas-applying/Cargo.toml

@@ -20,6 +20,8 @@ pallas-primitives = { version = "=0.25.0", path = "../pallas-primitives" }
 pallas-traverse = { version = "=0.25.0", path = "../pallas-traverse" }
 rand = "0.8"
 hex = "0.4"
+serde = { version = "1.0.136", optional = true, features = ["derive"] }
+serde_json = { version = "1.0.79", optional = true }
 
 [dev-dependencies]
 hex = "0.4"

pallas-applying/src/utils.rs

@@ -3,6 +3,9 @@
 pub mod environment;
 pub mod validation;
 
+#[cfg(feature = "json")]
+mod json;
+
 pub use environment::*;
 use pallas_addresses::{Address, ShelleyAddress, ShelleyPaymentPart};
 use pallas_codec::{
@@ -342,3 +345,70 @@ pub fn compute_plutus_v2_script_hash(script: &PlutusV2Script) -> PolicyId {
     payload.insert(0, 2);
     pallas_crypto::hash::Hasher::<224>::hash(&payload)
 }
+
+/// Computes the greatest common divisor of two integers using Euclid's algorithm
+/// (https://en.wikipedia.org/wiki/Euclidean_algorithm).
+/// (Taken from: https://gist.github.com/victor-iyi/8a84185c1d52419b0d4915a648d5e3e1)
+///
+/// # Example
+///
+/// ```rust
+/// assert_eq!(gcd(3, 5), 1);
+///
+/// assert_eq!(gcd(2 * 3 * 5 * 11 * 17, 3 * 7 * 11 * 13 * 19), 3 * 11);
+/// ```
+///
+/// ## List of numbers.
+///
+/// ```rust
+/// // Compute divisor one after the other.
+/// let numbers: [u64; 4] = [3, 9, 21, 81];
+///
+/// // Method 1: Using for-loop.
+/// let mut divisor: u64 = numbers[0];
+/// for no in &numbers[1..] {
+///     divisor = gcd(divisor, *no);
+/// }
+/// assert_eq!(divisor, 3);
+///
+/// // Method 2: Using iterator & fold.
+/// let divisor: u64 = numbers.iter().fold(numbers[0], |acc, &x| gcd(acc, x));
+/// assert_eq!(divisor, 3);
+/// ```
+pub fn gcd(mut n: u64, mut m: u64) -> u64 {
+    assert!(n != 0 && m != 0);
+    while m != 0 {
+        if m < n {
+            std::mem::swap(&mut m, &mut n);
+        }
+        m %= n;
+    }
+    n
+}
+
+#[test]
+fn test_gcd() {
+    // Simple greatest common divisor.
+    assert_eq!(gcd(3, 5), 1);
+    assert_eq!(gcd(14, 15), 1);
+
+    // More complex greatest common divisor.
+    assert_eq!(gcd(2 * 3 * 5 * 11 * 17, 3 * 7 * 11 * 13 * 19), 3 * 11);
+}
+
+#[test]
+fn test_multiple_gcd() {
+    // List of numbers.
+    let numbers: [u64; 4] = [3, 9, 21, 81];
+    // Compute divisor one after the other.
+    // Method 1: Using for-loop.
+    let mut divisor = numbers[0];
+    for no in &numbers[1..] {
+        divisor = gcd(divisor, *no);
+    }
+    assert_eq!(divisor, 3);
+
+    // Method 2: Using iterator & fold.
+    let divisor: u64 = numbers.iter().fold(numbers[0], |acc, &x| gcd(acc, x));
+    assert_eq!(divisor, 3);
+}