Deal with empty jpeg_tables

src/decoder/ifd.rs

@@ -10,8 +10,8 @@ use tags::{Tag, Type};
 use {TiffError, TiffFormatError, TiffResult, TiffUnsupportedError};
 
 use self::Value::{
-    Ascii, Byte, Double, Float, List, Rational, RationalBig, SRational, SRationalBig, Signed, SignedBig,
-    Unsigned, UnsignedBig,
+    Ascii, Byte, Double, Float, List, Rational, RationalBig, SRational, SRationalBig, Signed,
+    SignedBig, Unsigned, UnsignedBig,
 };
 
 #[allow(unused_qualifications)]
@@ -38,9 +38,7 @@ impl Value {
     pub fn into_u8(self) -> TiffResult<u8> {
         match self {
             Byte(val) => Ok(val),
-            val => Err(TiffError::FormatError(
-                TiffFormatError::ByteExpected(val),
-            )),
+            val => Err(TiffError::FormatError(TiffFormatError::ByteExpected(val))),
         }
     }
 
@@ -452,7 +450,7 @@ impl Entry {
                         let string = decoder.read_string(n)?;
                         Ok(Ascii(string))
                     }
-                },
+                }
                 (Type::UNDEFINED, n) => self.decode_offset(n, bo, limits, decoder, |decoder| {
                     Ok(Byte(u8::from(decoder.read_byte()?)))
                 }),

src/decoder/mod.rs

@@ -933,7 +933,12 @@ impl<R: Read + Seek> Decoder<R> {
     pub fn read_jpeg(&mut self) -> TiffResult<DecodingResult> {
         let offsets = self.get_tag_u32_vec(Tag::StripOffsets)?;
         let bytes = self.get_tag_u32_vec(Tag::StripByteCounts)?;
-        let jpeg_tables: Vec<u8> = self.get_tag_u8_vec(Tag::JPEGTables)?;
+
+        let jpeg_tables: Option<Vec<u8>> = match self.find_tag(Tag::JPEGTables) {
+            Ok(None) => None,
+            Ok(_) => Some(self.get_tag_u8_vec(Tag::JPEGTables)?),
+            Err(e) => return Err(e),
+        };
 
         if offsets.len() == 0 {
             return Err(TiffError::FormatError(TiffFormatError::RequiredTagEmpty(

src/decoder/stream.rs

@@ -329,7 +329,7 @@ pub(crate) struct JpegReader {
 impl JpegReader {
     /// Constructs new JpegReader wrapping a SmartReader.
     /// Because JPEG compression in TIFF allows to save quantization and/or huffman tables in one
-    /// central loacation, the constructor accepts this data as `jpeg_tables` here containing either
+    /// central location, the constructor accepts this data as `jpeg_tables` here containing either
     /// or both.
     /// These `jpeg_tables` are simply prepended to the remaining jpeg image data.
     /// Because these `jpeg_tables` start with a `SOI` (HEX: `0xFFD8`) or __start of image__ marker
@@ -342,7 +342,7 @@ impl JpegReader {
     pub fn new<R>(
         reader: &mut SmartReader<R>,
         length: u32,
-        jpeg_tables: &Vec<u8>,
+        jpeg_tables: &Option<Vec<u8>>,
     ) -> io::Result<JpegReader>
     where
         R: Read + Seek,
@@ -353,15 +353,25 @@ impl JpegReader {
         let mut segment = vec![0; length as usize];
         reader.read_exact(&mut segment[..])?;
 
-        let mut jpeg_data = jpeg_tables.clone();
-        jpeg_data.truncate(jpeg_data.len() - 2);
+        match jpeg_tables {
+            Some(tables) => {
+                let mut jpeg_data = tables.clone();
+                jpeg_data.truncate(jpeg_data.len() - 2);
+                jpeg_data.extend_from_slice(&mut segment[2..]);
 
-        jpeg_data.extend_from_slice(&mut segment[2..]);
+                Ok(JpegReader {
+                    buffer: io::Cursor::new(jpeg_data),
+                    byte_order: order,
+                })
+            },
+            None => {
+                Ok(JpegReader {
+                    buffer: io::Cursor::new(segment),
+                    byte_order: order,
+                })
+            }
+        }
 
-        Ok(JpegReader {
-            buffer: io::Cursor::new(jpeg_data),
-            byte_order: order,
-        })
     }
 }
 

src/error.rs

@@ -72,9 +72,7 @@ impl fmt::Display for TiffFormatError {
             UnknownPredictor(ref predictor) => {
                 write!(fmt, "Unknown predictor “{}” encountered", predictor)
             }
-            ByteExpected(ref val) => {
-                write!(fmt, "Expected byte, {:?} found.", val)
-            }
+            ByteExpected(ref val) => write!(fmt, "Expected byte, {:?} found.", val),
             UnsignedIntegerExpected(ref val) => {
                 write!(fmt, "Expected unsigned integer, {:?} found.", val)
             }
@@ -82,12 +80,8 @@ impl fmt::Display for TiffFormatError {
                 write!(fmt, "Expected signed integer, {:?} found.", val)
             }
             InflateError(_) => write!(fmt, "Failed to decode inflate data."),
-            Format(ref val) => {
-                write!(fmt, "Invalid format: {:?}.", val)
-            }
-            RequiredTagEmpty(ref val) => {
-                write!(fmt, "Required tag {:?} was empty.", val)
-            }
+            Format(ref val) => write!(fmt, "Invalid format: {:?}.", val),
+            RequiredTagEmpty(ref val) => write!(fmt, "Required tag {:?} was empty.", val),
             __NonExhaustive => unreachable!(),
         }
     }