Make it easy to access the contents of any hash (newtype)

src/hash160.rs

@@ -42,6 +42,7 @@ hex_fmt_impl!(LowerHex, Hash);
 index_impl!(Hash);
 serde_impl!(Hash, 20);
 borrow_slice_impl!(Hash);
+from_hash_for_inner_impl!(Hash);
 
 impl str::FromStr for Hash {
     type Err = ::hex::Error;

src/lib.rs

@@ -181,6 +181,12 @@ macro_rules! hash_newtype {
             }
         }
 
+        impl ::std::convert::From<$newtype> for <$hash as $crate::Hash>::Inner {
+            fn from(hashtype: $newtype) -> <$hash as $crate::Hash>::Inner {
+                hashtype.0.into_inner()
+            }
+        }
+
         impl $crate::Hash for $newtype {
             type Engine = <$hash as $crate::Hash>::Engine;
             type Inner = <$hash as $crate::Hash>::Inner;
@@ -242,5 +248,16 @@ mod test {
         let h2: TestNewtype = h.to_string().parse().unwrap();
         assert_eq!(h2.as_hash(), h);
     }
+
+    #[test]
+    fn convert_using_std_into() {
+        fn i_accept_plain_arrays<T: Into<[u8; 32]>>(whatever: T) {
+            let _x = whatever.into();
+        }
+
+        let h1 = TestNewtype::hash(&[]);
+
+        i_accept_plain_arrays(h1);
+    }
 }
 

src/ripemd160.rs

@@ -88,6 +88,7 @@ hex_fmt_impl!(LowerHex, Hash);
 index_impl!(Hash);
 serde_impl!(Hash, 20);
 borrow_slice_impl!(Hash);
+from_hash_for_inner_impl!(Hash);
 
 impl str::FromStr for Hash {
     type Err = ::hex::Error;

src/sha1.rs

@@ -83,6 +83,7 @@ hex_fmt_impl!(LowerHex, Hash);
 index_impl!(Hash);
 serde_impl!(Hash, 20);
 borrow_slice_impl!(Hash);
+from_hash_for_inner_impl!(Hash);
 
 impl str::FromStr for Hash {
     type Err = ::hex::Error;

src/sha256.rs

@@ -91,6 +91,7 @@ hex_fmt_impl!(LowerHex, Hash);
 index_impl!(Hash);
 serde_impl!(Hash, 32);
 borrow_slice_impl!(Hash);
+from_hash_for_inner_impl!(Hash);
 
 impl HashTrait for Hash {
     type Engine = HashEngine;

src/sha256d.rs

@@ -34,6 +34,7 @@ hex_fmt_impl!(LowerHex, Hash);
 index_impl!(Hash);
 serde_impl!(Hash, 32);
 borrow_slice_impl!(Hash);
+from_hash_for_inner_impl!(Hash);
 
 impl str::FromStr for Hash {
     type Err = ::hex::Error;

src/sha256t.rs

@@ -124,6 +124,12 @@ impl<T: Tag> HashTrait for Hash<T> {
     }
 }
 
+impl<T> From<Hash<T>> for <Hash<T> as HashTrait>::Inner where T: Tag {
+    fn from(hash: Hash<T>) -> Self {
+        hash.into_inner()
+    }
+}
+
 /// Macro used to define a newtype tagged hash.
 /// It creates two public types:
 /// - a sha246t::Tag struct,

src/sha512.rs

@@ -139,6 +139,7 @@ hex_fmt_impl!(LowerHex, Hash);
 index_impl!(Hash);
 serde_impl!(Hash, 64);
 borrow_slice_impl!(Hash);
+from_hash_for_inner_impl!(Hash);
 
 impl HashTrait for Hash {
     type Engine = HashEngine;

src/siphash24.rs

@@ -208,6 +208,7 @@ hex_fmt_impl!(LowerHex, Hash);
 index_impl!(Hash);
 serde_impl!(Hash, 8);
 borrow_slice_impl!(Hash);
+from_hash_for_inner_impl!(Hash);
 
 impl str::FromStr for Hash {
     type Err = ::hex::Error;

src/util.rs

@@ -144,6 +144,16 @@ macro_rules! engine_input_impl(
     )
 );
 
+macro_rules! from_hash_for_inner_impl(
+    ($hash:ty) => (
+        impl From<$hash> for <$hash as HashTrait>::Inner {
+            fn from(hash: $hash) -> Self {
+                hash.into_inner()
+            }
+        }
+    )
+);
+
 
 
 macro_rules! define_slice_to_be {