Add openssl sha2 impl

Cargo.toml

@@ -10,8 +10,9 @@ required-features = ["rustcrypto"]
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 [features]
-default = ["rustcrypto"]
-rustcrypto = ["sha2", "hex"]
+default = ["rustcrypto-sha2"]
+rustcrypto-sha2 = ["sha2", "hex"]
+openssl-sha2 = ["openssl", "hex"]
 
 [dependencies]
 contextual = "0.1.3"
@@ -23,6 +24,7 @@ rdf-types = "0.12.4"
 
 hex = { version = "0.4.3", optional = true }
 sha2 = { version = "0.10.6", optional = true }
+openssl = { version = "0.10.44", optional = true }
 
 [dev-dependencies]
 iref = "2.2.0"

src/lib.rs

@@ -11,9 +11,11 @@ use std::{
 
 mod input_dataset;
 mod issuer;
+#[cfg(feature = "openssl-sha2")]
+mod openssl_impls;
 mod output_dataset;
-#[cfg(feature = "rustcrypto")]
-mod sha2_impls;
+#[cfg(feature = "rustcrypto-sha2")]
+mod rustcrypto_impls;
 
 use input_dataset::{InputDataset, NormalizingQuad, Position, QuadSubject, QuadValue};
 use issuer::Issuer;

src/openssl_impls.rs

@@ -0,0 +1,13 @@
+use openssl::sha::Sha256;
+
+impl super::Sha256 for Sha256 {
+    fn update(&mut self, bytes: &[u8]) {
+        openssl::sha::Sha256::update(self, bytes)
+    }
+
+    fn finalize_hex_and_reset(&mut self) -> crate::HexHash {
+        let this = std::mem::replace(self, Sha256::default());
+
+        crate::HexHash(hex::encode(this.finish()))
+    }
+}