1 files changed, 68 insertions, 0 deletions
diff --git a/src/util.rs b/src/util.rs
new file mode 100644
index 0000000..428990c
--- /dev/null
+++ b/src/util.rs
@@ -0,0 +1,68 @@
+use std::fmt::{Debug, Display, Formatter, Pointer};
+use std::ops::Deref;
+use crypto::digest::Digest;
+use crypto::sha1::Sha1;
+use serde::{Deserialize, Deserializer};
+use serde::de::{Error, Visitor};
+use hex::{FromHex, ToHex};
+
+// sha1 digests are 20 bytes long
+pub const SHA1_DIGEST_BYTES: usize = 20;
+pub type Sha1DigestBytes = [u8; SHA1_DIGEST_BYTES];
+
+#[derive(PartialEq, Eq, PartialOrd, Ord, Clone)]
+pub struct Sha1Digest(pub Sha1DigestBytes);
+
+impl Debug for Sha1Digest {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        write!(f, "Sha1Digest {{{}}}", self.0.encode_hex::<String>())
+    }
+}
+
+impl Display for Sha1Digest {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        f.write_str(&self.0.encode_hex::<String>())
+    }
+}
+
+impl Sha1Digest {
+    pub fn verify(&self, s: &str) -> Result<(), Sha1Digest> {
+        let mut st = Sha1::new();
+        let mut dig = [0u8; SHA1_DIGEST_BYTES];
+
+        st.input_str(s);
+        st.result(&mut dig);
+
+        if self.0 == dig {
+            return Ok(());
+        }
+
+        Err(Sha1Digest(dig))
+    }
+}
+
+struct Sha1DigestVisitor;
+
+impl <'a> Visitor<'a> for Sha1DigestVisitor {
+    type Value = Sha1Digest;
+
+    fn expecting(&self, formatter: &mut Formatter) -> std::fmt::Result {
+        write!(formatter, "a valid SHA-1 digest (40-character hex string)")
+    }
+
+    fn visit_str<E>(self, v: &str) -> Result<Self::Value, E>
+    where
+        E: Error,
+    {
+        Sha1DigestBytes::from_hex(v).map_err(|e| E::custom(e)).map(Sha1Digest)
+    }
+}
+
+impl<'a> Deserialize<'a> for Sha1Digest {
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: Deserializer<'a>,
+    {
+        deserializer.deserialize_any(Sha1DigestVisitor)
+    }
+}
+\ No newline at end of file