Improve deflate support

- Switch to streaming decompression via `flate2`. Aside from performance improvements and lower RAM consumption, this fixes a bug where `max_uncompressed_length` was precalculated for a single tile but then used as a hard limit on the whole data, failing to decompress any tiled images.
 - Deprecate `InflateError` - this was used for wrapping `miniz_oxide` raw status, but `flate2` already reports them as `io::Error` instead. This makes errors from both Lzw and Deflate modes more consistent - they're all now just `io::Error`.
 - Add support for new `Deflate` tag in addition to `OldDeflate` - format-wise it's same Zlib, and on practice decodes successfully with the same underlying code.
 - Slightly simplify partial reads from the `Reader` by using the `std::io::copy` helper instead of doing it manually.

Fixes #131.

src/decoder/mod.rs

@@ -1084,7 +1084,7 @@ impl<R: Read + Seek> Decoder<R> {
         // Construct necessary reader to perform decompression.
         self.goto_offset_u64(offset)?;
         let byte_order = self.reader.byte_order;
-        let mut reader: Box<dyn Read> = match self.compression_method {
+        let reader: Box<dyn Read> = match self.compression_method {
             CompressionMethod::None => Box::new(&mut self.reader),
             CompressionMethod::LZW => Box::new(
                 LZWReader::new(
@@ -1097,8 +1097,8 @@ impl<R: Read + Seek> Decoder<R> {
             CompressionMethod::PackBits => {
                 Box::new(PackBitsReader::new(&mut self.reader, usize::try_from(length)?)?.1)
             }
-            CompressionMethod::OldDeflate => {
-                Box::new(DeflateReader::new(&mut self.reader, buffer.len() * buffer.byte_len())?.1)
+            CompressionMethod::Deflate | CompressionMethod::OldDeflate => {
+                Box::new(DeflateReader::new(&mut self.reader))
             }
             method => {
                 return Err(TiffError::UnsupportedError(
@@ -1109,7 +1109,7 @@ impl<R: Read + Seek> Decoder<R> {
 
         // Read into output buffer.
         {
-            let buffer = match &mut buffer {
+            let mut buffer = match &mut buffer {
                 DecodingBuffer::U8(buf) => &mut *buf,
                 DecodingBuffer::I8(buf) => bytecast::i8_as_ne_mut_bytes(buf),
                 DecodingBuffer::U16(buf) => bytecast::u16_as_ne_mut_bytes(buf),
@@ -1122,16 +1122,8 @@ impl<R: Read + Seek> Decoder<R> {
                 DecodingBuffer::F64(buf) => bytecast::f64_as_ne_mut_bytes(buf),
             };
 
-            let mut bytes_written = 0;
-            while bytes_written < buffer.len() {
-                match reader.read(&mut buffer[bytes_written..]) {
-                    Ok(0) => break,
-                    Ok(n) => bytes_written += n,
-                    Err(ref e) if e.kind() == io::ErrorKind::Interrupted => {}
-                    Err(e) => Err(e)?,
-                }
-            }
-            for b in &mut buffer[bytes_written..] {
+            std::io::copy(&mut reader.take(buffer.len() as u64), &mut buffer)?;
+            for b in buffer {
                 *b = 0;
             }
         }
@@ -1383,8 +1375,8 @@ impl<R: Read + Seek> Decoder<R> {
             CompressionMethod::PackBits => {
                 Box::new(PackBitsReader::new(reader, usize::try_from(compressed_length)?)?.1)
             }
-            CompressionMethod::OldDeflate => {
-                Box::new(DeflateReader::new(reader, samples * byte_len)?.1)
+            CompressionMethod::Deflate | CompressionMethod::OldDeflate => {
+                Box::new(DeflateReader::new(reader))
             }
             method => {
                 return Err(TiffError::UnsupportedError(

src/decoder/stream.rs

@@ -1,7 +1,5 @@
 //! All IO functionality needed for TIFF decoding
 
-use crate::error::{TiffError, TiffResult};
-use miniz_oxide::inflate;
 use std::io::{self, Read, Seek};
 
 /// Byte order of the TIFF file.
@@ -126,42 +124,7 @@ pub trait EndianReader: Read {
 /// ## Deflate Reader
 ///
 
-/// Reader that decompresses DEFLATE streams
-pub struct DeflateReader {
-    buffer: io::Cursor<Vec<u8>>,
-}
-
-impl DeflateReader {
-    pub fn new<R: Read + Seek>(
-        reader: &mut SmartReader<R>,
-        max_uncompressed_length: usize,
-    ) -> TiffResult<(usize, Self)> {
-        let mut compressed = Vec::new();
-        reader.read_to_end(&mut compressed)?;
-
-        // TODO: Implement streaming compression, and remove this (temporary) and somewhat
-        // misleading workaround.
-        if compressed.len() > max_uncompressed_length {
-            return Err(TiffError::LimitsExceeded);
-        }
-
-        let uncompressed =
-            inflate::decompress_to_vec_zlib(&compressed).map_err(TiffError::from_inflate_status)?;
-
-        Ok((
-            uncompressed.len(),
-            Self {
-                buffer: io::Cursor::new(uncompressed),
-            },
-        ))
-    }
-}
-
-impl Read for DeflateReader {
-    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
-        self.buffer.read(buf)
-    }
-}
+pub type DeflateReader<'r, R> = flate2::read::ZlibDecoder<&'r mut SmartReader<R>>;
 
 ///
 /// ## LZW Reader