Merge pull request #165 from fintelia/improve-predictor

Floating point predictor

src/decoder/image.rs

@@ -4,8 +4,8 @@ use super::stream::{
     PackBitsReader,
 };
 use super::tag_reader::TagReader;
+use super::{fp_predict_f32, fp_predict_f64, DecodingBuffer, Limits};
 use super::{stream::SmartReader, ChunkType};
-use super::{DecodingBuffer, Limits};
 use crate::tags::{CompressionMethod, PhotometricInterpretation, Predictor, SampleFormat, Tag};
 use crate::{ColorType, TiffError, TiffFormatError, TiffResult, TiffUnsupportedError};
 use std::convert::{TryFrom, TryInto};
@@ -399,7 +399,20 @@ impl Image {
             | (ColorType::CMYK(n), _)
             | (ColorType::Gray(n), _)
                 if usize::from(n) == buffer.byte_len() * 8 => {}
-            (ColorType::Gray(n), DecodingBuffer::U8(_)) if n <= 8 => {}
+            (ColorType::Gray(n), DecodingBuffer::U8(_)) if n < 8 => match self.predictor {
+                Predictor::None => {}
+                Predictor::Horizontal => {
+                    return Err(TiffError::UnsupportedError(
+                        TiffUnsupportedError::HorizontalPredictor(color_type),
+                    ))
+                }
+                Predictor::FloatingPoint => {
+                    return Err(TiffError::UnsupportedError(
+                        TiffUnsupportedError::FloatingPointPredictor(color_type),
+                    ));
+                }
+                Predictor::__NonExhaustive => unreachable!(),
+            },
             (type_, _) => {
                 return Err(TiffError::UnsupportedError(
                     TiffUnsupportedError::UnsupportedColorType(type_),
@@ -407,6 +420,24 @@ impl Image {
             }
         }
 
+        // Validate that the predictor is supported for the sample type.
+        match (self.predictor, &buffer) {
+            (Predictor::Horizontal, DecodingBuffer::F32(_))
+            | (Predictor::Horizontal, DecodingBuffer::F64(_)) => {
+                return Err(TiffError::UnsupportedError(
+                    TiffUnsupportedError::HorizontalPredictor(color_type),
+                ));
+            }
+            (Predictor::FloatingPoint, DecodingBuffer::F32(_))
+            | (Predictor::FloatingPoint, DecodingBuffer::F64(_)) => {}
+            (Predictor::FloatingPoint, _) => {
+                return Err(TiffError::UnsupportedError(
+                    TiffUnsupportedError::FloatingPointPredictor(color_type),
+                ));
+            }
+            _ => {}
+        }
+
         let compressed_bytes = self.chunk_bytes.get(chunk).ok_or(TiffError::FormatError(
             TiffFormatError::InconsistentSizesEncountered,
         ))?;
@@ -443,10 +474,33 @@ impl Image {
             let tile = &mut buffer.as_bytes_mut()[..total_samples * byte_len];
             reader.read_exact(tile)?;
 
-            super::fix_endianness(&mut buffer.subrange(0..total_samples), byte_order);
+            for row in 0..(chunk_dimensions.1 - padding.1) {
+                let row_start = row * output_width * samples;
+                let row_end = (row + 1) * output_width * samples;
+                let row = buffer.subrange(row_start..row_end);
+                super::fix_endianness_and_predict(row, samples, byte_order, predictor);
+            }
             if photometric_interpretation == PhotometricInterpretation::WhiteIsZero {
                 super::invert_colors(&mut buffer.subrange(0..total_samples), color_type);
             }
+        } else if padding.0 > 0 && self.predictor == Predictor::FloatingPoint {
+            // The floating point predictor shuffles the padding bytes into the encoded output, so
+            // this case is handled specially when needed.
+            let mut encoded = vec![0u8; chunk_dimensions.0 * samples * byte_len];
+            for row in 0..(chunk_dimensions.1 - padding.1) {
+                let row_start = row * output_width * samples;
+                let row_end = row_start + (chunk_dimensions.0 - padding.0) * samples;
+
+                reader.read_exact(&mut encoded)?;
+                match buffer.subrange(row_start..row_end) {
+                    DecodingBuffer::F32(buf) => fp_predict_f32(&mut encoded, buf, samples),
+                    DecodingBuffer::F64(buf) => fp_predict_f64(&mut encoded, buf, samples),
+                    _ => unreachable!(),
+                }
+                if photometric_interpretation == PhotometricInterpretation::WhiteIsZero {
+                    super::invert_colors(&mut buffer.subrange(row_start..row_end), color_type);
+                }
+            }
         } else {
             for row in 0..(chunk_dimensions.1 - padding.1) {
                 let row_start = row * output_width * samples;
@@ -461,29 +515,14 @@ impl Image {
                     io::copy(&mut reader.by_ref().take(len), &mut io::sink())?;
                 }
 
-                super::fix_endianness(&mut buffer.subrange(row_start..row_end), byte_order);
+                let mut row = buffer.subrange(row_start..row_end);
+                super::fix_endianness_and_predict(row.copy(), samples, byte_order, predictor);
                 if photometric_interpretation == PhotometricInterpretation::WhiteIsZero {
-                    super::invert_colors(&mut buffer.subrange(row_start..row_end), color_type);
+                    super::invert_colors(&mut row, color_type);
                 }
             }
         }
 
-        match predictor {
-            Predictor::None => {}
-            Predictor::Horizontal => {
-                super::rev_hpredict(
-                    buffer,
-                    (
-                        u32::try_from(chunk_dimensions.0 - padding.0)?,
-                        u32::try_from(chunk_dimensions.1 - padding.1)?,
-                    ),
-                    output_width,
-                    color_type,
-                )?;
-            }
-            Predictor::__NonExhaustive => unreachable!(),
-        }
-
         Ok(())
     }
 }

src/decoder/mod.rs

@@ -359,95 +359,78 @@ impl Wrapping for i64 {
     }
 }
 
-fn rev_hpredict_nsamp<T>(
-    image: &mut [T],
-    size: (u32, u32), // Size of the block
-    img_width: usize, // Width of the image (this distinction is needed for tiles)
-    samples: usize,
-) -> TiffResult<()>
-where
-    T: Copy + Wrapping,
-{
-    let width = usize::try_from(size.0)?;
-    let height = usize::try_from(size.1)?;
-    for row in 0..height {
-        for col in samples..width * samples {
-            let prev_pixel = image[(row * img_width * samples + col - samples)];
-            let pixel = &mut image[(row * img_width * samples + col)];
-            *pixel = pixel.wrapping_add(prev_pixel);
-        }
+fn rev_hpredict_nsamp<T: Copy + Wrapping>(image: &mut [T], samples: usize) {
+    for col in samples..image.len() {
+        image[col] = image[col].wrapping_add(image[col - samples]);
     }
-    Ok(())
 }
 
-fn rev_hpredict(
-    image: DecodingBuffer,
-    size: (u32, u32),
-    img_width: usize,
-    color_type: ColorType,
-) -> TiffResult<()> {
-    // TODO: use bits_per_sample.len() after implementing type 3 predictor
-    let samples = match color_type {
-        ColorType::Gray(8) | ColorType::Gray(16) | ColorType::Gray(32) | ColorType::Gray(64) => 1,
-        ColorType::RGB(8) | ColorType::RGB(16) | ColorType::RGB(32) | ColorType::RGB(64) => 3,
-        ColorType::RGBA(8)
-        | ColorType::RGBA(16)
-        | ColorType::RGBA(32)
-        | ColorType::RGBA(64)
-        | ColorType::CMYK(8)
-        | ColorType::CMYK(16)
-        | ColorType::CMYK(32)
-        | ColorType::CMYK(64) => 4,
-        _ => {
-            return Err(TiffError::UnsupportedError(
-                TiffUnsupportedError::HorizontalPredictor(color_type),
-            ))
-        }
-    };
+pub fn fp_predict_f32(input: &mut [u8], output: &mut [f32], samples: usize) {
+    rev_hpredict_nsamp(input, samples);
+    for i in 0..output.len() {
+        // TODO: use f32::from_be_bytes() when we can (version 1.40)
+        output[i] = f32::from_bits(u32::from_be_bytes([
+            input[input.len() / 4 * 0 + i],
+            input[input.len() / 4 * 1 + i],
+            input[input.len() / 4 * 2 + i],
+            input[input.len() / 4 * 3 + i],
+        ]));
+    }
+}
+
+pub fn fp_predict_f64(input: &mut [u8], output: &mut [f64], samples: usize) {
+    rev_hpredict_nsamp(input, samples);
+    for i in 0..output.len() {
+        // TODO: use f64::from_be_bytes() when we can (version 1.40)
+        output[i] = f64::from_bits(u64::from_be_bytes([
+            input[input.len() / 8 * 0 + i],
+            input[input.len() / 8 * 1 + i],
+            input[input.len() / 8 * 2 + i],
+            input[input.len() / 8 * 3 + i],
+            input[input.len() / 8 * 4 + i],
+            input[input.len() / 8 * 5 + i],
+            input[input.len() / 8 * 6 + i],
+            input[input.len() / 8 * 7 + i],
+        ]));
+    }
+}
 
-    match image {
-        DecodingBuffer::U8(buf) => {
-            rev_hpredict_nsamp(buf, size, img_width, samples)?;
-        }
-        DecodingBuffer::U16(buf) => {
-            rev_hpredict_nsamp(buf, size, img_width, samples)?;
-        }
-        DecodingBuffer::U32(buf) => {
-            rev_hpredict_nsamp(buf, size, img_width, samples)?;
-        }
-        DecodingBuffer::U64(buf) => {
-            rev_hpredict_nsamp(buf, size, img_width, samples)?;
-        }
-        DecodingBuffer::F32(_buf) => {
-            // FIXME: check how this is defined.
-            // See issue #89.
-            // rev_hpredict_nsamp(buf, size, img_width,samples)?;
-            return Err(TiffError::UnsupportedError(
-                TiffUnsupportedError::HorizontalPredictor(color_type),
-            ));
-        }
-        DecodingBuffer::F64(_buf) => {
-            //FIXME: check how this is defined.
-            // See issue #89.
-            // rev_hpredict_nsamp(buf, size, img_width,samples)?;
-            return Err(TiffError::UnsupportedError(
-                TiffUnsupportedError::HorizontalPredictor(color_type),
-            ));
-        }
-        DecodingBuffer::I8(buf) => {
-            rev_hpredict_nsamp(buf, size, img_width, samples)?;
-        }
-        DecodingBuffer::I16(buf) => {
-            rev_hpredict_nsamp(buf, size, img_width, samples)?;
+fn fix_endianness_and_predict(
+    mut image: DecodingBuffer,
+    samples: usize,
+    byte_order: ByteOrder,
+    predictor: Predictor,
+) {
+    match predictor {
+        Predictor::None => {
+            fix_endianness(&mut image, byte_order);
         }
-        DecodingBuffer::I32(buf) => {
-            rev_hpredict_nsamp(buf, size, img_width, samples)?;
+        Predictor::Horizontal => {
+            fix_endianness(&mut image, byte_order);
+            match image {
+                DecodingBuffer::U8(buf) => rev_hpredict_nsamp(buf, samples),
+                DecodingBuffer::U16(buf) => rev_hpredict_nsamp(buf, samples),
+                DecodingBuffer::U32(buf) => rev_hpredict_nsamp(buf, samples),
+                DecodingBuffer::U64(buf) => rev_hpredict_nsamp(buf, samples),
+                DecodingBuffer::I8(buf) => rev_hpredict_nsamp(buf, samples),
+                DecodingBuffer::I16(buf) => rev_hpredict_nsamp(buf, samples),
+                DecodingBuffer::I32(buf) => rev_hpredict_nsamp(buf, samples),
+                DecodingBuffer::I64(buf) => rev_hpredict_nsamp(buf, samples),
+                DecodingBuffer::F32(_) | DecodingBuffer::F64(_) => {
+                    unreachable!("Caller should have validated arguments. Please file a bug.")
+                }
+            }
         }
-        DecodingBuffer::I64(buf) => {
-            rev_hpredict_nsamp(buf, size, img_width, samples)?;
+        Predictor::FloatingPoint => {
+            let mut buffer_copy = image.as_bytes_mut().to_vec();
+            match image {
+                DecodingBuffer::F32(buf) => fp_predict_f32(&mut buffer_copy, buf, samples),
+                DecodingBuffer::F64(buf) => fp_predict_f64(&mut buffer_copy, buf, samples),
+                _ => unreachable!("Caller should have validated arguments. Please file a bug."),
+            }
         }
+        Predictor::__NonExhaustive => unreachable!(),
     }
-    Ok(())
 }
 
 fn invert_colors_unsigned<T>(buffer: &mut [T], max: T)

src/error.rs

@@ -134,6 +134,7 @@ impl fmt::Display for TiffFormatError {
 /// stability guarantees.
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub enum TiffUnsupportedError {
+    FloatingPointPredictor(ColorType),
     HorizontalPredictor(ColorType),
     InterpretationWithBits(PhotometricInterpretation, Vec<u8>),
     UnknownInterpretation,
@@ -154,6 +155,11 @@ impl fmt::Display for TiffUnsupportedError {
     fn fmt(&self, fmt: &mut fmt::Formatter) -> Result<(), fmt::Error> {
         use self::TiffUnsupportedError::*;
         match *self {
+            FloatingPointPredictor(color_type) => write!(
+                fmt,
+                "Floating point predictor for {:?} is unsupported.",
+                color_type
+            ),
             HorizontalPredictor(color_type) => write!(
                 fmt,
                 "Horizontal predictor for {:?} is unsupported.",

src/tags.rs

@@ -214,6 +214,7 @@ tags! {
 pub enum Predictor(u16) {
     None = 1,
     Horizontal = 2,
+    FloatingPoint = 3,
 }
 }
 

tests/decode_images.rs

@@ -494,3 +494,13 @@ fn timeout() {
 fn test_no_rows_per_strip() {
     test_image_sum_u8("no_rows_per_strip.tiff", ColorType::RGB(8), 99448840);
 }
+
+#[test]
+fn test_predictor_3_rgb_f32() {
+    test_image_sum_f32("predictor-3-rgb-f32.tif", ColorType::RGB(32), 54004.33);
+}
+
+#[test]
+fn test_predictor_3_gray_f32() {
+    test_image_sum_f32("predictor-3-gray-f32.tif", ColorType::Gray(32), 20008.275);
+}