replace Codec::from(u64) with TryFrom impl

src/cid.rs

@@ -192,7 +192,7 @@ impl TryFrom<&[u8]> for Cid {
             let version = Version::from(raw_version)?;
 
             let (raw_codec, hash) = varint_decode::u64(&remain)?;
-            let codec = Codec::from(raw_codec)?;
+            let codec = Codec::try_from(raw_codec)?;
 
             let mh = MultihashRef::from_slice(hash)?.to_owned();
 

src/codec.rs

@@ -1,3 +1,5 @@
+use std::convert::TryFrom;
+
 use crate::error::{Error, Result};
 
 macro_rules! build_codec_enum {
@@ -8,9 +10,11 @@ macro_rules! build_codec_enum {
             $( #[$attr] $codec, )*
         }
 
-        impl Codec {
+        impl TryFrom<u64> for Codec {
+            type Error = Error;
+
             /// Convert a number to the matching codec, or `Error` if unknown codec is matching.
-            pub fn from(raw: u64) -> Result<Codec> {
+            fn try_from(raw: u64) -> Result<Codec> {
                 match raw {
                     $( $code => Ok(Self::$codec), )*
                     _ => Err(Error::UnknownCodec),

src/prefix.rs

@@ -1,3 +1,5 @@
+use std::convert::TryFrom;
+
 use unsigned_varint::{decode as varint_decode, encode as varint_encode};
 
 use crate::codec::Codec;
@@ -24,7 +26,7 @@ impl Prefix {
         let version = Version::from(raw_version)?;
 
         let (raw_codec, remain) = varint_decode::u64(remain)?;
-        let codec = Codec::from(raw_codec)?;
+        let codec = Codec::try_from(raw_codec)?;
 
         let (raw_mh_type, remain) = varint_decode::u64(remain)?;
         let mh_type = match multihash::Code::from_u64(raw_mh_type) {