Move error code to bottom of file

Move the error code to the bottom of the file because it is boring and
should not be looked at.

Code move only, no other changes.

Author: tcharding

src/lib.rs

@@ -19,57 +19,6 @@ use core::fmt;
 
 use crate::types::*;
 
-/// Errors returned by [`libbitcoinconsensus`].
-///
-/// The error variant identifiers mimic those from `libbitcoinconsensus`.
-///
-/// [`libbitcoinconsensus`]: <https://github.com/bitcoin/bitcoin/blob/master/doc/shared-libraries.md#errors>
-#[allow(non_camel_case_types)]
-#[derive(Debug)]
-#[repr(C)]
-pub enum Error {
-    /// Default value, passed to `libbitcoinconsensus` as a return parameter.
-    ERR_SCRIPT = 0,
-    /// An invalid index for `txTo`.
-    ERR_TX_INDEX,
-    /// `txToLen` did not match with the size of `txTo`.
-    ERR_TX_SIZE_MISMATCH,
-    /// An error deserializing `txTo`.
-    ERR_TX_DESERIALIZE,
-    /// Input amount is required if WITNESS is used.
-    ERR_AMOUNT_REQUIRED,
-    /// Script verification `flags` are invalid (i.e. not part of the libconsensus interface).
-    ERR_INVALID_FLAGS,
-}
-
-impl fmt::Display for Error {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        use self::Error::*;
-
-        let s = match *self {
-            ERR_SCRIPT => "error value was not set (value still 0)",
-            ERR_TX_INDEX => "an invalid index for txTo",
-            ERR_TX_SIZE_MISMATCH => "txToLen did not match with the size of txTo",
-            ERR_TX_DESERIALIZE => "an error deserializing txTo",
-            ERR_AMOUNT_REQUIRED => "input amount is required if WITNESS is used",
-            ERR_INVALID_FLAGS => "script verification flags are invalid",
-        };
-        f.write_str(s)
-    }
-}
-
-#[cfg(feature = "std")]
-impl std::error::Error for Error {
-    fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
-        use self::Error::*;
-
-        match *self {
-            ERR_SCRIPT | ERR_TX_INDEX | ERR_TX_SIZE_MISMATCH | ERR_TX_DESERIALIZE
-            | ERR_AMOUNT_REQUIRED | ERR_INVALID_FLAGS => None,
-        }
-    }
-}
-
 /// Do not enable any verification.
 pub const VERIFY_NONE: c_uint = 0;
 /// Evaluate P2SH (BIP16) subscripts.
@@ -207,6 +156,57 @@ pub fn verify_with_flags(
     }
 }
 
+/// Errors returned by [`libbitcoinconsensus`].
+///
+/// The error variant identifiers mimic those from `libbitcoinconsensus`.
+///
+/// [`libbitcoinconsensus`]: <https://github.com/bitcoin/bitcoin/blob/master/doc/shared-libraries.md#errors>
+#[allow(non_camel_case_types)]
+#[derive(Debug)]
+#[repr(C)]
+pub enum Error {
+    /// Default value, passed to `libbitcoinconsensus` as a return parameter.
+    ERR_SCRIPT = 0,
+    /// An invalid index for `txTo`.
+    ERR_TX_INDEX,
+    /// `txToLen` did not match with the size of `txTo`.
+    ERR_TX_SIZE_MISMATCH,
+    /// An error deserializing `txTo`.
+    ERR_TX_DESERIALIZE,
+    /// Input amount is required if WITNESS is used.
+    ERR_AMOUNT_REQUIRED,
+    /// Script verification `flags` are invalid (i.e. not part of the libconsensus interface).
+    ERR_INVALID_FLAGS,
+}
+
+impl fmt::Display for Error {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        use self::Error::*;
+
+        let s = match *self {
+            ERR_SCRIPT => "error value was not set (value still 0)",
+            ERR_TX_INDEX => "an invalid index for txTo",
+            ERR_TX_SIZE_MISMATCH => "txToLen did not match with the size of txTo",
+            ERR_TX_DESERIALIZE => "an error deserializing txTo",
+            ERR_AMOUNT_REQUIRED => "input amount is required if WITNESS is used",
+            ERR_INVALID_FLAGS => "script verification flags are invalid",
+        };
+        f.write_str(s)
+    }
+}
+
+#[cfg(feature = "std")]
+impl std::error::Error for Error {
+    fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
+        use self::Error::*;
+
+        match *self {
+            ERR_SCRIPT | ERR_TX_INDEX | ERR_TX_SIZE_MISMATCH | ERR_TX_DESERIALIZE
+            | ERR_AMOUNT_REQUIRED | ERR_INVALID_FLAGS => None,
+        }
+    }
+}
+
 #[cfg(test)]
 mod tests {
     extern crate rustc_serialize as serialize;