Import 'ryu' crate version 1.0.5

Bug: 163175424
Test: N/A
Change-Id: I7bda5411adccb26198c53ed1cb41fc6bb08468d7
diff --git a/src/parse.rs b/src/parse.rs
new file mode 100644
index 0000000..00f7983
--- /dev/null
+++ b/src/parse.rs
@@ -0,0 +1,19 @@
+use core::fmt::{self, Display};
+
+#[derive(Copy, Clone, Debug)]
+pub enum Error {
+    InputTooShort,
+    InputTooLong,
+    MalformedInput,
+}
+
+impl Display for Error {
+    fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+        let msg = match self {
+            Error::InputTooShort => "input too short",
+            Error::InputTooLong => "input too long",
+            Error::MalformedInput => "malformed input",
+        };
+        formatter.write_str(msg)
+    }
+}