Add byte expected error and cleanup

src/decoder/ifd.rs

@@ -39,7 +39,7 @@ impl Value {
         match self {
             Byte(val) => Ok(val),
             val => Err(TiffError::FormatError(
-                TiffFormatError::UnsignedIntegerExpected(val),
+                TiffFormatError::ByteExpected(val),
             )),
         }
     }
@@ -454,7 +454,7 @@ impl Entry {
                     }
                 },
                 (Type::UNDEFINED, n) => self.decode_offset(n, bo, limits, decoder, |decoder| {
-                    Ok(Unsigned(u32::from(decoder.read_byte()?)))
+                    Ok(Byte(u8::from(decoder.read_byte()?)))
                 }),
                 _ => Err(TiffError::UnsupportedError(
                     TiffUnsupportedError::UnsupportedDataType,

src/decoder/mod.rs

@@ -11,7 +11,6 @@ use tags::{CompressionMethod, PhotometricInterpretation, Predictor, SampleFormat
 use self::stream::{
     ByteOrder, DeflateReader, EndianReader, LZWReader, PackBitsReader, SmartReader, JpegReader
 };
-use tags::{CompressionMethod, PhotometricInterpretation, Predictor, Tag, Type};
 
 pub mod ifd;
 mod stream;

src/error.rs

@@ -45,6 +45,7 @@ pub enum TiffFormatError {
     InvalidTagValueType(Tag),
     RequiredTagNotFound(Tag),
     UnknownPredictor(u16),
+    ByteExpected(Value),
     UnsignedIntegerExpected(Value),
     SignedIntegerExpected(Value),
     InflateError(InflateError),
@@ -69,6 +70,9 @@ impl fmt::Display for TiffFormatError {
             UnknownPredictor(ref predictor) => {
                 write!(fmt, "Unknown predictor “{}” encountered", predictor)
             }
+            ByteExpected(ref val) => {
+                write!(fmt, "Expected byte, {:?} found.", val)
+            }
             UnsignedIntegerExpected(ref val) => {
                 write!(fmt, "Expected unsigned integer, {:?} found.", val)
             }

src/tags.rs

@@ -111,11 +111,6 @@ pub enum Tag(u16) unknown("A private or extension tag") {
     Threshholding = 263, // TODO add support
     XResolution = 282,
     YResolution = 283,
-    TileWidth = 322,
-    TileLength = 323,
-    TileOffsets = 324,
-    TileByteCounts = 325,
-    SampleFormat = 339,
     // JPEG
     JPEGTables = 347,
     // Advanced tags