diff --git a/src/encoding.rs b/src/encoding.rs
index 099ee8da8..73b49c0f2 100644
--- a/src/encoding.rs
+++ b/src/encoding.rs
@@ -28,9 +28,9 @@ pub enum Encoding<'a> {
     Class,
     Sel,
     Unknown,
-    BitField(u32),
+    BitField(u8),
     Pointer(&'a Encoding<'a>),
-    Array(u32, &'a Encoding<'a>),
+    Array(usize, &'a Encoding<'a>),
     Struct(&'a str, &'a [Encoding<'a>]),
     Union(&'a str, &'a [Encoding<'a>]),
 }
diff --git a/src/parse.rs b/src/parse.rs
index 645776fce..4a2a04386 100644
--- a/src/parse.rs
+++ b/src/parse.rs
@@ -75,7 +75,7 @@ fn rm_enc_prefix<'a>(s: &'a str, enc: &Encoding) -> Option<&'a str> {
     rm_prefix(s, code)
 }
 
-fn chomp_int(s: &str) -> Option<(u32, &str)> {
+fn chomp_int(s: &str) -> Option<(usize, &str)> {
     // Chomp until we hit a non-digit
     let (num, t) = match s.find(|c: char| !c.is_digit(10)) {
         Some(i) => s.split_at(i),
@@ -84,7 +84,7 @@ fn chomp_int(s: &str) -> Option<(u32, &str)> {
     num.parse().map(|n| (n, t)).ok()
 }
 
-fn rm_int_prefix(s: &str, other: u32) -> Option<&str> {
+fn rm_int_prefix(s: &str, other: usize) -> Option<&str> {
     chomp_int(s)
         .and_then(|(n, t)| if other == n { Some(t) } else { None })
 }