Return a usize for the unit length from get_type_info().

src/tiff.rs

@@ -82,21 +82,21 @@ fn parse_ifd<E>(data: &[u8], offset: usize)
     for i in 0..count as usize {
         let tag = E::loadu16(data, offset + 2 + i * 12);
         let typ = E::loadu16(data, offset + 2 + i * 12 + 2);
-        let cnt = E::loadu32(data, offset + 2 + i * 12 + 4);
+        let cnt = E::loadu32(data, offset + 2 + i * 12 + 4) as usize;
         let ofs = E::loadu32(data, offset + 2 + i * 12 + 8) as usize;
         let (unitlen, parser) = get_type_info::<E>(typ);
         let vallen = try!(unitlen.checked_mul(cnt).ok_or(
-            Error::InvalidFormat("Invalid entry count"))) as usize;
+            Error::InvalidFormat("Invalid entry count")));
         let val;
         if unitlen == 0 {
-            val = Value::Unknown(typ, cnt, ofs as u32);
+            val = Value::Unknown(typ, cnt as u32, ofs as u32);
         } else if vallen <= 4 {
-            val = parser(data, offset + 2 + i * 12 + 8, cnt as usize);
+            val = parser(data, offset + 2 + i * 12 + 8, cnt);
         } else {
             if data.len() < ofs || data.len() - ofs < vallen {
                 return Err(Error::InvalidFormat("Truncated IFD"));
             }
-            val = parser(data, ofs, cnt as usize);
+            val = parser(data, ofs, cnt);
         }
         fields.push(Field { tag: Tag(tag), value: val });
     }

src/value.rs

@@ -45,7 +45,7 @@ type Parser<'a> = fn(&'a [u8], usize, usize) -> Value<'a>;
 
 // Return the length of a single value and the parser of the type.
 pub fn get_type_info<'a, E>(typecode: u16)
-                            -> (u32, Parser<'a>) where E: Endian {
+                            -> (usize, Parser<'a>) where E: Endian {
     match typecode {
         2 => (1, parse_ascii),
         3 => (2, parse_short::<E>),