Add a convinience constructor for the new BigEndianScalar

[ldk-c-bindings] / lightning-c-bindings / src / c_types / mod.rs

diff --git a/lightning-c-bindings/src/c_types/mod.rs b/lightning-c-bindings/src/c_types/mod.rs
index 3b574073fcdd23fd100e1dcf05bf7e120159098d..3f8c900be02fd4d767d37eabddb21bcb859fa016 100644 (file)
--- a/lightning-c-bindings/src/c_types/mod.rs
+++ b/lightning-c-bindings/src/c_types/mod.rs
@@ -11,6 +11,7 @@ use bitcoin::secp256k1::ecdsa::Signature as SecpSignature;
 use bitcoin::secp256k1::Error as SecpError;
 use bitcoin::secp256k1::ecdsa::RecoveryId;
 use bitcoin::secp256k1::ecdsa::RecoverableSignature as SecpRecoverableSignature;
+use bitcoin::secp256k1::Scalar as SecpScalar;
 use bitcoin::bech32;
 use bitcoin::util::address;
 
@@ -149,6 +150,28 @@ impl RecoverableSignature {
        }
 }
 
+#[repr(C)]
+#[derive(Clone)]
+/// Represents a scalar value between zero and the secp256k1 curve order, in big endian.
+pub struct BigEndianScalar {
+       /// The bytes of the scalar value.
+       pub big_endian_bytes: [u8; 32],
+}
+impl BigEndianScalar {
+       pub(crate) fn from_rust(scalar: &SecpScalar) -> Self {
+               Self { big_endian_bytes: scalar.to_be_bytes() }
+       }
+       pub(crate) fn into_rust(&self) -> SecpScalar {
+               SecpScalar::from_be_bytes(self.big_endian_bytes).expect("Scalar greater than the curve order")
+       }
+}
+
+#[no_mangle]
+/// Convenience function for constructing a new BigEndianScalar
+pub extern "C" fn BigEndianScalar_new(big_endian_bytes: ThirtyTwoBytes) -> BigEndianScalar {
+       BigEndianScalar { big_endian_bytes: big_endian_bytes.data }
+}
+
 #[repr(C)]
 #[derive(Copy, Clone)]
 /// Represents an error returned from libsecp256k1 during validation of some secp256k1 data