Create consensus utils and move byte_reverse_hex function to it (#705)

* move byte_reverse_hex function

zebra-chain/src/lib.rs

@@ -24,6 +24,7 @@ pub mod proofs;
 pub mod serialization;
 pub mod transaction;
 pub mod types;
+pub mod utils;
 
 pub use ed25519_zebra;
 pub use redjubjub;

zebra-chain/src/utils.rs

@@ -0,0 +1,15 @@
+//! Utility functions for chain data.
+
+/// Returns the hexadecimal-encoded string `s` in byte-reversed order.
+pub fn byte_reverse_hex(s: &str) -> String {
+    String::from_utf8(
+        s.as_bytes()
+            .chunks(2)
+            .rev()
+            .map(|c| c.iter())
+            .flatten()
+            .cloned()
+            .collect::<Vec<u8>>(),
+    )
+    .expect("input should be ascii")
+}

zebrad/src/commands/revhex.rs

@@ -16,20 +16,6 @@ pub struct RevhexCmd {
     input: String,
 }
 
-/// Returns the hexadecimal-encoded string `s` in byte-reversed order.
-fn byte_reverse_hex(s: &str) -> String {
-    String::from_utf8(
-        s.as_bytes()
-            .chunks(2)
-            .rev()
-            .map(|c| c.iter())
-            .flatten()
-            .cloned()
-            .collect::<Vec<u8>>(),
-    )
-    .expect("input should be ascii")
-}
-
 impl Runnable for RevhexCmd {
     /// Print endian-reversed hex string.
     fn run(&self) {
@@ -40,10 +26,10 @@ impl Runnable for RevhexCmd {
             // We can distinguish EOF from an empty line, because the newline is
             // included in the buffer, so empty lines return Ok(1).
             while stdin().read_line(&mut input).unwrap_or(0) > 0 {
-                println!("{}", byte_reverse_hex(&input.trim()));
+                println!("{}", zebra_chain::utils::byte_reverse_hex(&input.trim()));
             }
         } else {
-            println!("{}", byte_reverse_hex(&self.input));
+            println!("{}", zebra_chain::utils::byte_reverse_hex(&self.input));
         }
     }
 }