Initial vendor packages

Signed-off-by: Valentin Popov <valentin@popov.link>

1 files changed, 259 insertions, 0 deletions

diff --git a/vendor/jpeg-decoder/src/decoder/lossless.rs b/vendor/jpeg-decoder/src/decoder/lossless.rs
new file mode 100644
index 0000000..6422220
--- /dev/null
+++ b/vendor/jpeg-decoder/src/decoder/lossless.rs
@@ -0,0 +1,259 @@
+use std::io::Read;
+use crate::decoder::{Decoder, MAX_COMPONENTS};
+use crate::error::{Error, Result};
+use crate::huffman::HuffmanDecoder;
+use crate::marker::Marker;
+use crate::parser::Predictor;
+use crate::parser::{Component, FrameInfo, ScanInfo};
+
+impl<R: Read> Decoder<R> {
+    /// decode_scan_lossless
+    pub fn decode_scan_lossless(
+        &mut self,
+        frame: &FrameInfo,
+        scan: &ScanInfo,
+    ) -> Result<(Option<Marker>, Vec<Vec<u16>>)> {
+        let ncomp = scan.component_indices.len();
+        let npixel = frame.image_size.height as usize * frame.image_size.width as usize;
+        assert!(ncomp <= MAX_COMPONENTS);
+        let mut results = vec![vec![0u16; npixel]; ncomp];
+
+        let components: Vec<Component> = scan
+            .component_indices
+            .iter()
+            .map(|&i| frame.components[i].clone())
+            .collect();
+
+        // Verify that all required huffman tables has been set.
+        if scan
+            .dc_table_indices
+            .iter()
+            .any(|&i| self.dc_huffman_tables[i].is_none())
+        {
+            return Err(Error::Format(
+                "scan makes use of unset dc huffman table".to_owned(),
+            ));
+        }
+
+        let mut huffman = HuffmanDecoder::new();
+        let reader = &mut self.reader;
+        let mut mcus_left_until_restart = self.restart_interval;
+        let mut expected_rst_num = 0;
+        let mut ra = [0u16; MAX_COMPONENTS];
+        let mut rb = [0u16; MAX_COMPONENTS];
+        let mut rc = [0u16; MAX_COMPONENTS];
+
+        let width = frame.image_size.width as usize;
+        let height = frame.image_size.height as usize;
+
+        let mut differences = vec![Vec::with_capacity(npixel); ncomp];
+        for _mcu_y in 0..height {
+            for _mcu_x in 0..width {
+                if self.restart_interval > 0 {
+                    if mcus_left_until_restart == 0 {
+                        match huffman.take_marker(reader)? {
+                            Some(Marker::RST(n)) => {
+                                if n != expected_rst_num {
+                                    return Err(Error::Format(format!(
+                                        "found RST{} where RST{} was expected",
+                                        n, expected_rst_num
+                                    )));
+                                }
+
+                                huffman.reset();
+
+                                expected_rst_num = (expected_rst_num + 1) % 8;
+                                mcus_left_until_restart = self.restart_interval;
+                            }
+                            Some(marker) => {
+                                return Err(Error::Format(format!(
+                                    "found marker {:?} inside scan where RST{} was expected",
+                                    marker, expected_rst_num
+                                )))
+                            }
+                            None => {
+                                return Err(Error::Format(format!(
+                                    "no marker found where RST{} was expected",
+                                    expected_rst_num
+                                )))
+                            }
+                        }
+                    }
+
+                    mcus_left_until_restart -= 1;
+                }
+
+                for (i, _component) in components.iter().enumerate() {
+                    let dc_table = self.dc_huffman_tables[scan.dc_table_indices[i]]
+                        .as_ref()
+                        .unwrap();
+                    let value = huffman.decode(reader, dc_table)?;
+                    let diff = match value {
+                        0 => 0,
+                        1..=15 => huffman.receive_extend(reader, value)? as i32,
+                        16 => 32768,
+                        _ => {
+                            // Section F.1.2.1.1
+                            // Table F.1
+                            return Err(Error::Format(
+                                "invalid DC difference magnitude category".to_owned(),
+                            ));
+                        }
+                    };
+                    differences[i].push(diff);
+                }
+            }
+        }
+
+        if scan.predictor_selection == Predictor::Ra {
+            for (i, _component) in components.iter().enumerate() {
+                // calculate the top left pixel
+                let diff = differences[i][0];
+                let prediction = 1 << (frame.precision - scan.point_transform - 1) as i32;
+                let result = ((prediction + diff) & 0xFFFF) as u16; // modulo 2^16
+                let result = result << scan.point_transform;
+                results[i][0] = result;
+
+                // calculate leftmost column, using top pixel as predictor
+                let mut previous = result;
+                for mcu_y in 1..height {
+                    let diff = differences[i][mcu_y * width];
+                    let prediction = previous as i32;
+                    let result = ((prediction + diff) & 0xFFFF) as u16; // modulo 2^16
+                    let result = result << scan.point_transform;
+                    results[i][mcu_y * width] = result;
+                    previous = result;
+                }
+
+                // calculate rows, using left pixel as predictor
+                for mcu_y in 0..height {
+                    for mcu_x in 1..width {
+                        let diff = differences[i][mcu_y * width + mcu_x];
+                        let prediction = results[i][mcu_y * width + mcu_x - 1] as i32;
+                        let result = ((prediction + diff) & 0xFFFF) as u16; // modulo 2^16
+                        let result = result << scan.point_transform;
+                        results[i][mcu_y * width + mcu_x] = result;
+                    }
+                }
+            }
+        } else {
+            for mcu_y in 0..height {
+                for mcu_x in 0..width {
+                    for (i, _component) in components.iter().enumerate() {
+                        let diff = differences[i][mcu_y * width + mcu_x];
+
+                        // The following lines could be further optimized, e.g. moving the checks
+                        // and updates of the previous values into the prediction function or
+                        // iterating such that diagonals with mcu_x + mcu_y = const are computed at
+                        // the same time to exploit independent predictions in this case
+                        if mcu_x > 0 {
+                            ra[i] = results[i][mcu_y * frame.image_size.width as usize + mcu_x - 1];
+                        }
+                        if mcu_y > 0 {
+                            rb[i] =
+                                results[i][(mcu_y - 1) * frame.image_size.width as usize + mcu_x];
+                            if mcu_x > 0 {
+                                rc[i] = results[i]
+                                    [(mcu_y - 1) * frame.image_size.width as usize + (mcu_x - 1)];
+                            }
+                        }
+                        let prediction = predict(
+                            ra[i] as i32,
+                            rb[i] as i32,
+                            rc[i] as i32,
+                            scan.predictor_selection,
+                            scan.point_transform,
+                            frame.precision,
+                            mcu_x,
+                            mcu_y,
+                            self.restart_interval > 0
+                                && mcus_left_until_restart == self.restart_interval - 1,
+                        );
+                        let result = ((prediction + diff) & 0xFFFF) as u16; // modulo 2^16
+                        results[i][mcu_y * width + mcu_x] = result << scan.point_transform;
+                    }
+                }
+            }
+        }
+
+        let mut marker = huffman.take_marker(&mut self.reader)?;
+        while let Some(Marker::RST(_)) = marker {
+            marker = self.read_marker().ok();
+        }
+        Ok((marker, results))
+    }
+}
+
+/// H.1.2.1
+fn predict(
+    ra: i32,
+    rb: i32,
+    rc: i32,
+    predictor: Predictor,
+    point_transform: u8,
+    input_precision: u8,
+    ix: usize,
+    iy: usize,
+    restart: bool,
+) -> i32 {
+    if (ix == 0 && iy == 0) || restart {
+        // start of first line or restart
+        if input_precision > 1 + point_transform {
+            1 << (input_precision - point_transform - 1)
+        } else {
+            0
+        }
+    } else if iy == 0 {
+        // rest of first line
+        ra
+    } else if ix == 0 {
+        // start of other line
+        rb
+    } else {
+        // use predictor Table H.1
+        match predictor {
+            Predictor::NoPrediction => 0,
+            Predictor::Ra => ra,
+            Predictor::Rb => rb,
+            Predictor::Rc => rc,
+            Predictor::RaRbRc1 => ra + rb - rc,
+            Predictor::RaRbRc2 => ra + ((rb - rc) >> 1),
+            Predictor::RaRbRc3 => rb + ((ra - rc) >> 1),
+            Predictor::RaRb => (ra + rb) / 2,
+        }
+    }
+}
+
+pub fn compute_image_lossless(frame: &FrameInfo, mut data: Vec<Vec<u16>>) -> Result<Vec<u8>> {
+    if data.is_empty() || data.iter().any(Vec::is_empty) {
+        return Err(Error::Format("not all components have data".to_owned()));
+    }
+    let output_size = frame.output_size;
+    let components = &frame.components;
+    let ncomp = components.len();
+
+    if ncomp == 1 {
+        let decoded = convert_to_u8(frame, data.remove(0));
+        Ok(decoded)
+    } else {
+        let mut decoded: Vec<u16> =
+            vec![0u16; ncomp * output_size.width as usize * output_size.height as usize];
+        for (x, chunk) in decoded.chunks_mut(ncomp).enumerate() {
+            for (i, (component_data, _)) in data.iter().zip(components.iter()).enumerate() {
+                chunk[i] = component_data[x];
+            }
+        }
+        let decoded = convert_to_u8(frame, decoded);
+        Ok(decoded)
+    }
+}
+
+fn convert_to_u8(frame: &FrameInfo, data: Vec<u16>) -> Vec<u8> {
+    if frame.precision == 8 {
+        data.iter().map(|x| *x as u8).collect()
+    } else {
+        // we output native endian, which is the standard for image-rs
+        let ne_bytes: Vec<_> = data.iter().map(|x| x.to_ne_bytes()).collect();
+        ne_bytes.concat()
+    }
+}