From 0945e25aff204b0f316f0e9b3aa8ac6ee6f86600 Mon Sep 17 00:00:00 2001
From: Mateusz Kowalczyk <fuuzetsu@fuuzetsu.co.uk>
Date: Mon, 4 Dec 2023 13:26:09 +0900
Subject: [PATCH] Optional support for borsh serialisation

---
 Cargo.toml |  7 ++++++-
 src/lib.rs | 30 ++++++++++++++++++++++++++++++
 2 files changed, 36 insertions(+), 1 deletion(-)

diff --git a/Cargo.toml b/Cargo.toml
index 96a8623..0ecdedb 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -14,7 +14,7 @@ exclude = ["/bors.toml", "/ci/*", "/.github/*"]
 edition = "2018"
 
 [package.metadata.docs.rs]
-features = ["std", "num-bigint-std", "serde"]
+features = ["std", "num-bigint-std", "serde", "borsh"]
 
 [dependencies]
 
@@ -38,6 +38,11 @@ optional = true
 version = "1.0.0"
 default-features = false
 
+[dependencies.borsh]
+optional = true
+version = "1.2.0"
+default-features = false
+
 [features]
 default = ["num-bigint-std", "std"]
 std = ["num-integer/std", "num-traits/std"]
diff --git a/src/lib.rs b/src/lib.rs
index 8992406..78413d7 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1166,6 +1166,36 @@ where
     }
 }
 
+#[cfg(feature = "borsh")]
+impl<T> borsh::BorshSerialize for Ratio<T>
+where
+    T: borsh::BorshSerialize,
+{
+    fn serialize<W: borsh::io::Write>(&self, writer: &mut W) -> borsh::io::Result<()> {
+        <T as borsh::BorshSerialize>::serialize(self.numer(), writer)?;
+        <T as borsh::BorshSerialize>::serialize(self.denom(), writer)
+    }
+}
+
+#[cfg(feature = "borsh")]
+impl<T> borsh::BorshDeserialize for Ratio<T>
+where
+    T: borsh::BorshDeserialize + num_traits::Zero,
+{
+    fn deserialize_reader<R: borsh::io::Read>(reader: &mut R) -> borsh::io::Result<Self> {
+        let numer = <T as borsh::BorshDeserialize>::deserialize_reader(reader)?;
+        let denom = <T as borsh::BorshDeserialize>::deserialize_reader(reader)?;
+        if denom.is_zero() {
+            Err(borsh::io::Error::new(
+                borsh::io::ErrorKind::InvalidData,
+                "expected a ratio with non-zero denominator",
+            ))
+        } else {
+            Ok(Ratio::new_raw(numer, denom))
+        }
+    }
+}
+
 // FIXME: Bubble up specific errors
 #[derive(Copy, Clone, Debug, PartialEq)]
 pub struct ParseRatioError {