| use byteorder::ReadBytesExt; |
| use error::{Error, Result, UnsupportedFeature}; |
| use huffman::{fill_default_mjpeg_tables, HuffmanDecoder, HuffmanTable}; |
| use marker::Marker; |
| use parser::{AdobeColorTransform, AppData, CodingProcess, Component, Dimensions, EntropyCoding, FrameInfo, |
| parse_app, parse_com, parse_dht, parse_dqt, parse_dri, parse_sof, parse_sos, ScanInfo}; |
| use upsampler::Upsampler; |
| use std::cmp; |
| use std::io::{BufRead, BufReader, Read}; |
| use std::mem; |
| use std::ops::Range; |
| use std::sync::Arc; |
| use worker::{RowData, PlatformWorker, Worker}; |
| |
| pub const MAX_COMPONENTS: usize = 4; |
| |
| static UNZIGZAG: [u8; 64] = [ |
| 0, 1, 8, 16, 9, 2, 3, 10, |
| 17, 24, 32, 25, 18, 11, 4, 5, |
| 12, 19, 26, 33, 40, 48, 41, 34, |
| 27, 20, 13, 6, 7, 14, 21, 28, |
| 35, 42, 49, 56, 57, 50, 43, 36, |
| 29, 22, 15, 23, 30, 37, 44, 51, |
| 58, 59, 52, 45, 38, 31, 39, 46, |
| 53, 60, 61, 54, 47, 55, 62, 63, |
| ]; |
| |
| /// An enumeration over combinations of color spaces and bit depths a pixel can have. |
| #[derive(Clone, Copy, Debug, PartialEq)] |
| pub enum PixelFormat { |
| /// Luminance (grayscale), 8 bits |
| L8, |
| /// RGB, 8 bits per channel |
| RGB24, |
| /// CMYK, 8 bits per channel |
| CMYK32, |
| } |
| |
| impl PixelFormat { |
| /// Determine the size in bytes of each pixel in this format |
| pub fn pixel_bytes(&self) -> usize { |
| match self { |
| PixelFormat::L8 => 1, |
| PixelFormat::RGB24 => 3, |
| PixelFormat::CMYK32 => 4, |
| } |
| } |
| } |
| |
| /// Represents metadata of an image. |
| #[derive(Clone, Copy, Debug, PartialEq)] |
| pub struct ImageInfo { |
| /// The width of the image, in pixels. |
| pub width: u16, |
| /// The height of the image, in pixels. |
| pub height: u16, |
| /// The pixel format of the image. |
| pub pixel_format: PixelFormat, |
| } |
| |
| /// JPEG decoder |
| pub struct Decoder<R> { |
| reader: BufReader<R>, |
| |
| frame: Option<FrameInfo>, |
| dc_huffman_tables: Vec<Option<HuffmanTable>>, |
| ac_huffman_tables: Vec<Option<HuffmanTable>>, |
| quantization_tables: [Option<Arc<[u16; 64]>>; 4], |
| |
| restart_interval: u16, |
| color_transform: Option<AdobeColorTransform>, |
| is_jfif: bool, |
| is_mjpeg: bool, |
| |
| // Used for progressive JPEGs. |
| coefficients: Vec<Vec<i16>>, |
| // Bitmask of which coefficients has been completely decoded. |
| coefficients_finished: [u64; MAX_COMPONENTS], |
| } |
| |
| impl<R: Read> Decoder<R> { |
| /// Creates a new `Decoder` using the reader `reader`. |
| pub fn new(reader: R) -> Decoder<R> { |
| Decoder { |
| reader: BufReader::new(reader), |
| frame: None, |
| dc_huffman_tables: vec![None, None, None, None], |
| ac_huffman_tables: vec![None, None, None, None], |
| quantization_tables: [None, None, None, None], |
| restart_interval: 0, |
| color_transform: None, |
| is_jfif: false, |
| is_mjpeg: false, |
| coefficients: Vec::new(), |
| coefficients_finished: [0; MAX_COMPONENTS], |
| } |
| } |
| |
| /// Returns metadata about the image. |
| /// |
| /// The returned value will be `None` until a call to either `read_info` or `decode` has |
| /// returned `Ok`. |
| pub fn info(&self) -> Option<ImageInfo> { |
| match self.frame { |
| Some(ref frame) => { |
| let pixel_format = match frame.components.len() { |
| 1 => PixelFormat::L8, |
| 3 => PixelFormat::RGB24, |
| 4 => PixelFormat::CMYK32, |
| _ => panic!(), |
| }; |
| |
| Some(ImageInfo { |
| width: frame.output_size.width, |
| height: frame.output_size.height, |
| pixel_format: pixel_format, |
| }) |
| }, |
| None => None, |
| } |
| } |
| |
| /// Tries to read metadata from the image without decoding it. |
| /// |
| /// If successful, the metadata can be obtained using the `info` method. |
| pub fn read_info(&mut self) -> Result<()> { |
| self.decode_internal(true).map(|_| ()) |
| } |
| |
| /// Configure the decoder to scale the image during decoding. |
| /// |
| /// This efficiently scales the image by the smallest supported scale |
| /// factor that produces an image larger than or equal to the requested |
| /// size in at least one axis. The currently implemented scale factors |
| /// are 1/8, 1/4, 1/2 and 1. |
| /// |
| /// To generate a thumbnail of an exact size, pass the desired size and |
| /// then scale to the final size using a traditional resampling algorithm. |
| pub fn scale(&mut self, requested_width: u16, requested_height: u16) -> Result<(u16, u16)> { |
| self.read_info()?; |
| let frame = self.frame.as_mut().unwrap(); |
| let idct_size = crate::idct::choose_idct_size(frame.image_size, Dimensions{ width: requested_width, height: requested_height }); |
| frame.update_idct_size(idct_size); |
| Ok((frame.output_size.width, frame.output_size.height)) |
| } |
| |
| /// Decodes the image and returns the decoded pixels if successful. |
| pub fn decode(&mut self) -> Result<Vec<u8>> { |
| self.decode_internal(false) |
| } |
| |
| fn decode_internal(&mut self, stop_after_metadata: bool) -> Result<Vec<u8>> { |
| if stop_after_metadata && self.frame.is_some() { |
| // The metadata has already been read. |
| return Ok(Vec::new()); |
| } |
| else if self.frame.is_none() && (self.reader.read_u8()? != 0xFF || Marker::from_u8(self.reader.read_u8()?) != Some(Marker::SOI)) { |
| return Err(Error::Format("first two bytes is not a SOI marker".to_owned())); |
| } |
| |
| let mut previous_marker = Marker::SOI; |
| let mut pending_marker = None; |
| let mut worker = None; |
| let mut scans_processed = 0; |
| let mut planes = vec![Vec::new(); self.frame.as_ref().map_or(0, |frame| frame.components.len())]; |
| |
| loop { |
| let marker = match pending_marker.take() { |
| Some(m) => m, |
| None => self.read_marker()?, |
| }; |
| |
| match marker { |
| // Frame header |
| Marker::SOF(..) => { |
| // Section 4.10 |
| // "An image contains only one frame in the cases of sequential and |
| // progressive coding processes; an image contains multiple frames for the |
| // hierarchical mode." |
| if self.frame.is_some() { |
| return Err(Error::Unsupported(UnsupportedFeature::Hierarchical)); |
| } |
| |
| let frame = parse_sof(&mut self.reader, marker)?; |
| let component_count = frame.components.len(); |
| |
| if frame.is_differential { |
| return Err(Error::Unsupported(UnsupportedFeature::Hierarchical)); |
| } |
| if frame.coding_process == CodingProcess::Lossless { |
| return Err(Error::Unsupported(UnsupportedFeature::Lossless)); |
| } |
| if frame.entropy_coding == EntropyCoding::Arithmetic { |
| return Err(Error::Unsupported(UnsupportedFeature::ArithmeticEntropyCoding)); |
| } |
| if frame.precision != 8 { |
| return Err(Error::Unsupported(UnsupportedFeature::SamplePrecision(frame.precision))); |
| } |
| if frame.image_size.height == 0 { |
| return Err(Error::Unsupported(UnsupportedFeature::DNL)); |
| } |
| if component_count != 1 && component_count != 3 && component_count != 4 { |
| return Err(Error::Unsupported(UnsupportedFeature::ComponentCount(component_count as u8))); |
| } |
| |
| // Make sure we support the subsampling ratios used. |
| let _ = Upsampler::new(&frame.components, frame.image_size.width, frame.image_size.height)?; |
| |
| self.frame = Some(frame); |
| |
| if stop_after_metadata { |
| return Ok(Vec::new()); |
| } |
| |
| planes = vec![Vec::new(); component_count]; |
| }, |
| |
| // Scan header |
| Marker::SOS => { |
| if self.frame.is_none() { |
| return Err(Error::Format("scan encountered before frame".to_owned())); |
| } |
| if worker.is_none() { |
| worker = Some(PlatformWorker::new()?); |
| } |
| |
| let frame = self.frame.clone().unwrap(); |
| let scan = parse_sos(&mut self.reader, &frame)?; |
| |
| if frame.coding_process == CodingProcess::DctProgressive && self.coefficients.is_empty() { |
| self.coefficients = frame.components.iter().map(|c| { |
| let block_count = c.block_size.width as usize * c.block_size.height as usize; |
| vec![0; block_count * 64] |
| }).collect(); |
| } |
| |
| if scan.successive_approximation_low == 0 { |
| for &i in scan.component_indices.iter() { |
| for j in scan.spectral_selection.clone() { |
| self.coefficients_finished[i] |= 1 << j; |
| } |
| } |
| } |
| |
| let is_final_scan = scan.component_indices.iter().all(|&i| self.coefficients_finished[i] == !0); |
| let (marker, data) = self.decode_scan(&frame, &scan, worker.as_mut().unwrap(), is_final_scan)?; |
| |
| if let Some(data) = data { |
| for (i, plane) in data.into_iter().enumerate().filter(|&(_, ref plane)| !plane.is_empty()) { |
| planes[i] = plane; |
| } |
| } |
| |
| pending_marker = marker; |
| scans_processed += 1; |
| }, |
| |
| // Table-specification and miscellaneous markers |
| // Quantization table-specification |
| Marker::DQT => { |
| let tables = parse_dqt(&mut self.reader)?; |
| |
| for (i, &table) in tables.iter().enumerate() { |
| if let Some(table) = table { |
| let mut unzigzagged_table = [0u16; 64]; |
| |
| for j in 0 .. 64 { |
| unzigzagged_table[UNZIGZAG[j] as usize] = table[j]; |
| } |
| |
| self.quantization_tables[i] = Some(Arc::new(unzigzagged_table)); |
| } |
| } |
| }, |
| // Huffman table-specification |
| Marker::DHT => { |
| let is_baseline = self.frame.as_ref().map(|frame| frame.is_baseline); |
| let (dc_tables, ac_tables) = parse_dht(&mut self.reader, is_baseline)?; |
| |
| let current_dc_tables = mem::replace(&mut self.dc_huffman_tables, vec![]); |
| self.dc_huffman_tables = dc_tables.into_iter() |
| .zip(current_dc_tables.into_iter()) |
| .map(|(a, b)| a.or(b)) |
| .collect(); |
| |
| let current_ac_tables = mem::replace(&mut self.ac_huffman_tables, vec![]); |
| self.ac_huffman_tables = ac_tables.into_iter() |
| .zip(current_ac_tables.into_iter()) |
| .map(|(a, b)| a.or(b)) |
| .collect(); |
| }, |
| // Arithmetic conditioning table-specification |
| Marker::DAC => return Err(Error::Unsupported(UnsupportedFeature::ArithmeticEntropyCoding)), |
| // Restart interval definition |
| Marker::DRI => self.restart_interval = parse_dri(&mut self.reader)?, |
| // Comment |
| Marker::COM => { |
| let _comment = parse_com(&mut self.reader)?; |
| }, |
| // Application data |
| Marker::APP(..) => { |
| if let Some(data) = parse_app(&mut self.reader, marker)? { |
| match data { |
| AppData::Adobe(color_transform) => self.color_transform = Some(color_transform), |
| AppData::Jfif => { |
| // From the JFIF spec: |
| // "The APP0 marker is used to identify a JPEG FIF file. |
| // The JPEG FIF APP0 marker is mandatory right after the SOI marker." |
| // Some JPEGs in the wild does not follow this though, so we allow |
| // JFIF headers anywhere APP0 markers are allowed. |
| /* |
| if previous_marker != Marker::SOI { |
| return Err(Error::Format("the JFIF APP0 marker must come right after the SOI marker".to_owned())); |
| } |
| */ |
| |
| self.is_jfif = true; |
| }, |
| AppData::Avi1 => self.is_mjpeg = true, |
| } |
| } |
| }, |
| // Restart |
| Marker::RST(..) => { |
| // Some encoders emit a final RST marker after entropy-coded data, which |
| // decode_scan does not take care of. So if we encounter one, we ignore it. |
| if previous_marker != Marker::SOS { |
| return Err(Error::Format("RST found outside of entropy-coded data".to_owned())); |
| } |
| }, |
| |
| // Define number of lines |
| Marker::DNL => { |
| // Section B.2.1 |
| // "If a DNL segment (see B.2.5) is present, it shall immediately follow the first scan." |
| if previous_marker != Marker::SOS || scans_processed != 1 { |
| return Err(Error::Format("DNL is only allowed immediately after the first scan".to_owned())); |
| } |
| |
| return Err(Error::Unsupported(UnsupportedFeature::DNL)); |
| }, |
| |
| // Hierarchical mode markers |
| Marker::DHP | Marker::EXP => return Err(Error::Unsupported(UnsupportedFeature::Hierarchical)), |
| |
| // End of image |
| Marker::EOI => break, |
| |
| _ => return Err(Error::Format(format!("{:?} marker found where not allowed", marker))), |
| } |
| |
| previous_marker = marker; |
| } |
| |
| if planes.is_empty() || planes.iter().any(|plane| plane.is_empty()) { |
| return Err(Error::Format("no data found".to_owned())); |
| } |
| |
| let frame = self.frame.as_ref().unwrap(); |
| compute_image(&frame.components, planes, frame.output_size, self.is_jfif, self.color_transform) |
| } |
| |
| fn read_marker(&mut self) -> Result<Marker> { |
| loop { |
| |
| // This should be an error as the JPEG spec doesn't allow extraneous data between marker segments. |
| // libjpeg allows this though and there are images in the wild utilising it, so we are |
| // forced to support this behavior. |
| // Sony Ericsson P990i is an example of a device which produce this sort of JPEGs. |
| loop { |
| let buf = self.reader.fill_buf()?; |
| |
| if let Some(pos) = buf.iter().position(|&b| b == 0xFF) { |
| self.reader.consume(pos); |
| break; |
| } |
| |
| // Woah, a full page of not-0xFF. Let's try the next page. |
| let consumed = buf.len(); |
| self.reader.consume(consumed); |
| }; |
| |
| // Section B.1.1.2 |
| // All markers are assigned two-byte codes: an X’FF’ byte followed by a |
| // byte which is not equal to 0 or X’FF’ (see Table B.1). Any marker may |
| // optionally be preceded by any number of fill bytes, which are bytes |
| // assigned code X’FF’. |
| // So, let's find the byte after 0xFF. |
| let byte = loop { |
| let buf = self.reader.fill_buf()?; |
| |
| if let Some(pos) = buf.iter().position(|&b| b != 0xFF) { |
| let byte = buf[pos]; |
| self.reader.consume(pos + 1); |
| break byte; |
| } |
| |
| let consumed = buf.len(); |
| self.reader.consume(consumed); |
| }; |
| |
| if byte != 0x00 && byte != 0xFF { |
| return Ok(Marker::from_u8(byte).unwrap()); |
| } |
| } |
| } |
| |
| fn decode_scan(&mut self, |
| frame: &FrameInfo, |
| scan: &ScanInfo, |
| worker: &mut PlatformWorker, |
| produce_data: bool) |
| -> Result<(Option<Marker>, Option<Vec<Vec<u8>>>)> { |
| assert!(scan.component_indices.len() <= MAX_COMPONENTS); |
| |
| let components: Vec<Component> = scan.component_indices.iter() |
| .map(|&i| frame.components[i].clone()) |
| .collect(); |
| |
| // Verify that all required quantization tables has been set. |
| if components.iter().any(|component| self.quantization_tables[component.quantization_table_index].is_none()) { |
| return Err(Error::Format("use of unset quantization table".to_owned())); |
| } |
| |
| if self.is_mjpeg { |
| fill_default_mjpeg_tables(scan, &mut self.dc_huffman_tables, &mut self.ac_huffman_tables); |
| } |
| |
| // Verify that all required huffman tables has been set. |
| if scan.spectral_selection.start == 0 && |
| 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())); |
| } |
| if scan.spectral_selection.end > 1 && |
| scan.ac_table_indices.iter().any(|&i| self.ac_huffman_tables[i].is_none()) { |
| return Err(Error::Format("scan makes use of unset ac huffman table".to_owned())); |
| } |
| |
| if produce_data { |
| // Prepare the worker thread for the work to come. |
| for (i, component) in components.iter().enumerate() { |
| let row_data = RowData { |
| index: i, |
| component: component.clone(), |
| quantization_table: self.quantization_tables[component.quantization_table_index].clone().unwrap(), |
| }; |
| |
| worker.start(row_data)?; |
| } |
| } |
| |
| let blocks_per_mcu: Vec<u16> = components.iter() |
| .map(|c| c.horizontal_sampling_factor as u16 * c.vertical_sampling_factor as u16) |
| .collect(); |
| let is_progressive = frame.coding_process == CodingProcess::DctProgressive; |
| let is_interleaved = components.len() > 1; |
| let mut dummy_block = [0i16; 64]; |
| let mut huffman = HuffmanDecoder::new(); |
| let mut dc_predictors = [0i16; MAX_COMPONENTS]; |
| let mut mcus_left_until_restart = self.restart_interval; |
| let mut expected_rst_num = 0; |
| let mut eob_run = 0; |
| let mut mcu_row_coefficients = Vec::with_capacity(components.len()); |
| |
| if produce_data && !is_progressive { |
| for component in &components { |
| let coefficients_per_mcu_row = component.block_size.width as usize * component.vertical_sampling_factor as usize * 64; |
| mcu_row_coefficients.push(vec![0i16; coefficients_per_mcu_row]); |
| } |
| } |
| |
| for mcu_y in 0 .. frame.mcu_size.height { |
| for mcu_x in 0 .. frame.mcu_size.width { |
| for (i, component) in components.iter().enumerate() { |
| for j in 0 .. blocks_per_mcu[i] { |
| let (block_x, block_y) = if is_interleaved { |
| // Section A.2.3 |
| (mcu_x * component.horizontal_sampling_factor as u16 + j % component.horizontal_sampling_factor as u16, |
| mcu_y * component.vertical_sampling_factor as u16 + j / component.horizontal_sampling_factor as u16) |
| } |
| else { |
| // Section A.2.2 |
| |
| let blocks_per_row = component.block_size.width as usize; |
| let block_num = (mcu_y as usize * frame.mcu_size.width as usize + |
| mcu_x as usize) * blocks_per_mcu[i] as usize + j as usize; |
| |
| let x = (block_num % blocks_per_row) as u16; |
| let y = (block_num / blocks_per_row) as u16; |
| |
| if x * component.dct_scale as u16 >= component.size.width || y * component.dct_scale as u16 >= component.size.height { |
| continue; |
| } |
| |
| (x, y) |
| }; |
| |
| let block_offset = (block_y as usize * component.block_size.width as usize + block_x as usize) * 64; |
| let mcu_row_offset = mcu_y as usize * component.block_size.width as usize * component.vertical_sampling_factor as usize * 64; |
| let coefficients = if is_progressive { |
| &mut self.coefficients[scan.component_indices[i]][block_offset .. block_offset + 64] |
| } else if produce_data { |
| &mut mcu_row_coefficients[i][block_offset - mcu_row_offset .. block_offset - mcu_row_offset + 64] |
| } else { |
| &mut dummy_block[..] |
| }; |
| |
| if scan.successive_approximation_high == 0 { |
| decode_block(&mut self.reader, |
| coefficients, |
| &mut huffman, |
| self.dc_huffman_tables[scan.dc_table_indices[i]].as_ref(), |
| self.ac_huffman_tables[scan.ac_table_indices[i]].as_ref(), |
| scan.spectral_selection.clone(), |
| scan.successive_approximation_low, |
| &mut eob_run, |
| &mut dc_predictors[i])?; |
| } |
| else { |
| decode_block_successive_approximation(&mut self.reader, |
| coefficients, |
| &mut huffman, |
| self.ac_huffman_tables[scan.ac_table_indices[i]].as_ref(), |
| scan.spectral_selection.clone(), |
| scan.successive_approximation_low, |
| &mut eob_run)?; |
| } |
| } |
| } |
| |
| if self.restart_interval > 0 { |
| let is_last_mcu = mcu_x == frame.mcu_size.width - 1 && mcu_y == frame.mcu_size.height - 1; |
| mcus_left_until_restart -= 1; |
| |
| if mcus_left_until_restart == 0 && !is_last_mcu { |
| match huffman.take_marker(&mut self.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(); |
| // Section F.2.1.3.1 |
| dc_predictors = [0i16; MAX_COMPONENTS]; |
| // Section G.1.2.2 |
| eob_run = 0; |
| |
| 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))), |
| } |
| } |
| } |
| } |
| |
| if produce_data { |
| // Send the coefficients from this MCU row to the worker thread for dequantization and idct. |
| for (i, component) in components.iter().enumerate() { |
| let coefficients_per_mcu_row = component.block_size.width as usize * component.vertical_sampling_factor as usize * 64; |
| |
| let row_coefficients = if is_progressive { |
| let offset = mcu_y as usize * coefficients_per_mcu_row; |
| self.coefficients[scan.component_indices[i]][offset .. offset + coefficients_per_mcu_row].to_vec() |
| } else { |
| mem::replace(&mut mcu_row_coefficients[i], vec![0i16; coefficients_per_mcu_row]) |
| }; |
| |
| worker.append_row((i, row_coefficients))?; |
| } |
| } |
| } |
| |
| let mut marker = huffman.take_marker(&mut self.reader)?; |
| while let Some(Marker::RST(_)) = marker { |
| marker = self.read_marker().ok(); |
| } |
| |
| if produce_data { |
| // Retrieve all the data from the worker thread. |
| let mut data = vec![Vec::new(); frame.components.len()]; |
| |
| for (i, &component_index) in scan.component_indices.iter().enumerate() { |
| data[component_index] = worker.get_result(i)?; |
| } |
| |
| Ok((marker, Some(data))) |
| } |
| else { |
| Ok((marker, None)) |
| } |
| } |
| } |
| |
| fn decode_block<R: Read>(reader: &mut R, |
| coefficients: &mut [i16], |
| huffman: &mut HuffmanDecoder, |
| dc_table: Option<&HuffmanTable>, |
| ac_table: Option<&HuffmanTable>, |
| spectral_selection: Range<u8>, |
| successive_approximation_low: u8, |
| eob_run: &mut u16, |
| dc_predictor: &mut i16) -> Result<()> { |
| debug_assert_eq!(coefficients.len(), 64); |
| |
| if spectral_selection.start == 0 { |
| // Section F.2.2.1 |
| // Figure F.12 |
| let value = huffman.decode(reader, dc_table.unwrap())?; |
| let diff = match value { |
| 0 => 0, |
| _ => { |
| // Section F.1.2.1.1 |
| // Table F.1 |
| if value > 11 { |
| return Err(Error::Format("invalid DC difference magnitude category".to_owned())); |
| } |
| |
| huffman.receive_extend(reader, value)? |
| }, |
| }; |
| |
| // Malicious JPEG files can cause this add to overflow, therefore we use wrapping_add. |
| // One example of such a file is tests/crashtest/images/dc-predictor-overflow.jpg |
| *dc_predictor = dc_predictor.wrapping_add(diff); |
| coefficients[0] = *dc_predictor << successive_approximation_low; |
| } |
| |
| let mut index = cmp::max(spectral_selection.start, 1); |
| |
| if index < spectral_selection.end && *eob_run > 0 { |
| *eob_run -= 1; |
| return Ok(()); |
| } |
| |
| // Section F.1.2.2.1 |
| while index < spectral_selection.end { |
| if let Some((value, run)) = huffman.decode_fast_ac(reader, ac_table.unwrap())? { |
| index += run; |
| |
| if index >= spectral_selection.end { |
| break; |
| } |
| |
| coefficients[UNZIGZAG[index as usize] as usize] = value << successive_approximation_low; |
| index += 1; |
| } |
| else { |
| let byte = huffman.decode(reader, ac_table.unwrap())?; |
| let r = byte >> 4; |
| let s = byte & 0x0f; |
| |
| if s == 0 { |
| match r { |
| 15 => index += 16, // Run length of 16 zero coefficients. |
| _ => { |
| *eob_run = (1 << r) - 1; |
| |
| if r > 0 { |
| *eob_run += huffman.get_bits(reader, r)?; |
| } |
| |
| break; |
| }, |
| } |
| } |
| else { |
| index += r; |
| |
| if index >= spectral_selection.end { |
| break; |
| } |
| |
| coefficients[UNZIGZAG[index as usize] as usize] = huffman.receive_extend(reader, s)? << successive_approximation_low; |
| index += 1; |
| } |
| } |
| } |
| |
| Ok(()) |
| } |
| |
| fn decode_block_successive_approximation<R: Read>(reader: &mut R, |
| coefficients: &mut [i16], |
| huffman: &mut HuffmanDecoder, |
| ac_table: Option<&HuffmanTable>, |
| spectral_selection: Range<u8>, |
| successive_approximation_low: u8, |
| eob_run: &mut u16) -> Result<()> { |
| debug_assert_eq!(coefficients.len(), 64); |
| |
| let bit = 1 << successive_approximation_low; |
| |
| if spectral_selection.start == 0 { |
| // Section G.1.2.1 |
| |
| if huffman.get_bits(reader, 1)? == 1 { |
| coefficients[0] |= bit; |
| } |
| } |
| else { |
| // Section G.1.2.3 |
| |
| if *eob_run > 0 { |
| *eob_run -= 1; |
| refine_non_zeroes(reader, coefficients, huffman, spectral_selection, 64, bit)?; |
| return Ok(()); |
| } |
| |
| let mut index = spectral_selection.start; |
| |
| while index < spectral_selection.end { |
| let byte = huffman.decode(reader, ac_table.unwrap())?; |
| let r = byte >> 4; |
| let s = byte & 0x0f; |
| |
| let mut zero_run_length = r; |
| let mut value = 0; |
| |
| match s { |
| 0 => { |
| match r { |
| 15 => { |
| // Run length of 16 zero coefficients. |
| // We don't need to do anything special here, zero_run_length is 15 |
| // and then value (which is zero) gets written, resulting in 16 |
| // zero coefficients. |
| }, |
| _ => { |
| *eob_run = (1 << r) - 1; |
| |
| if r > 0 { |
| *eob_run += huffman.get_bits(reader, r)?; |
| } |
| |
| // Force end of block. |
| zero_run_length = 64; |
| }, |
| } |
| }, |
| 1 => { |
| if huffman.get_bits(reader, 1)? == 1 { |
| value = bit; |
| } |
| else { |
| value = -bit; |
| } |
| }, |
| _ => return Err(Error::Format("unexpected huffman code".to_owned())), |
| } |
| |
| let range = Range { |
| start: index, |
| end: spectral_selection.end, |
| }; |
| index = refine_non_zeroes(reader, coefficients, huffman, range, zero_run_length, bit)?; |
| |
| if value != 0 { |
| coefficients[UNZIGZAG[index as usize] as usize] = value; |
| } |
| |
| index += 1; |
| } |
| } |
| |
| Ok(()) |
| } |
| |
| fn refine_non_zeroes<R: Read>(reader: &mut R, |
| coefficients: &mut [i16], |
| huffman: &mut HuffmanDecoder, |
| range: Range<u8>, |
| zrl: u8, |
| bit: i16) -> Result<u8> { |
| debug_assert_eq!(coefficients.len(), 64); |
| |
| let last = range.end - 1; |
| let mut zero_run_length = zrl; |
| |
| for i in range { |
| let index = UNZIGZAG[i as usize] as usize; |
| |
| if coefficients[index] == 0 { |
| if zero_run_length == 0 { |
| return Ok(i); |
| } |
| |
| zero_run_length -= 1; |
| } |
| else if huffman.get_bits(reader, 1)? == 1 && coefficients[index] & bit == 0 { |
| if coefficients[index] > 0 { |
| coefficients[index] += bit; |
| } |
| else { |
| coefficients[index] -= bit; |
| } |
| } |
| } |
| |
| Ok(last) |
| } |
| |
| fn compute_image(components: &[Component], |
| mut data: Vec<Vec<u8>>, |
| output_size: Dimensions, |
| is_jfif: bool, |
| color_transform: Option<AdobeColorTransform>) -> Result<Vec<u8>> { |
| if data.iter().any(|data| data.is_empty()) { |
| return Err(Error::Format("not all components has data".to_owned())); |
| } |
| |
| if components.len() == 1 { |
| let component = &components[0]; |
| let mut decoded: Vec<u8> = data.remove(0); |
| |
| let width = component.size.width as usize; |
| let height = component.size.height as usize; |
| let size = width * height; |
| let line_stride = component.block_size.width as usize * component.dct_scale; |
| |
| // if the image width is a multiple of the block size, |
| // then we don't have to move bytes in the decoded data |
| if usize::from(output_size.width) != line_stride { |
| let mut buffer = vec![0u8; width]; |
| // The first line already starts at index 0, so we need to move only lines 1..height |
| for y in 1..height { |
| let destination_idx = y * width; |
| let source_idx = y * line_stride; |
| // We could use copy_within, but we need to support old rust versions |
| buffer.copy_from_slice(&decoded[source_idx..][..width]); |
| let destination = &mut decoded[destination_idx..][..width]; |
| destination.copy_from_slice(&buffer); |
| } |
| } |
| decoded.resize(size, 0); |
| Ok(decoded) |
| } |
| else { |
| compute_image_parallel(components, data, output_size, is_jfif, color_transform) |
| } |
| } |
| |
| #[cfg(feature="rayon")] |
| fn compute_image_parallel(components: &[Component], |
| data: Vec<Vec<u8>>, |
| output_size: Dimensions, |
| is_jfif: bool, |
| color_transform: Option<AdobeColorTransform>) -> Result<Vec<u8>> { |
| use rayon::prelude::*; |
| |
| let color_convert_func = choose_color_convert_func(components.len(), is_jfif, color_transform)?; |
| let upsampler = Upsampler::new(components, output_size.width, output_size.height)?; |
| let line_size = output_size.width as usize * components.len(); |
| let mut image = vec![0u8; line_size * output_size.height as usize]; |
| |
| image.par_chunks_mut(line_size) |
| .with_max_len(1) |
| .enumerate() |
| .for_each(|(row, line)| { |
| upsampler.upsample_and_interleave_row(&data, row, output_size.width as usize, line); |
| color_convert_func(line, output_size.width as usize); |
| }); |
| |
| Ok(image) |
| } |
| |
| #[cfg(not(feature="rayon"))] |
| fn compute_image_parallel(components: &[Component], |
| data: Vec<Vec<u8>>, |
| output_size: Dimensions, |
| is_jfif: bool, |
| color_transform: Option<AdobeColorTransform>) -> Result<Vec<u8>> { |
| let color_convert_func = choose_color_convert_func(components.len(), is_jfif, color_transform)?; |
| let upsampler = Upsampler::new(components, output_size.width, output_size.height)?; |
| let line_size = output_size.width as usize * components.len(); |
| let mut image = vec![0u8; line_size * output_size.height as usize]; |
| |
| for (row, line) in image.chunks_mut(line_size) |
| .enumerate() { |
| upsampler.upsample_and_interleave_row(&data, row, output_size.width as usize, line); |
| color_convert_func(line, output_size.width as usize); |
| } |
| |
| Ok(image) |
| } |
| |
| fn choose_color_convert_func(component_count: usize, |
| _is_jfif: bool, |
| color_transform: Option<AdobeColorTransform>) |
| -> Result<fn(&mut [u8], usize)> { |
| match component_count { |
| 3 => { |
| // http://www.sno.phy.queensu.ca/~phil/exiftool/TagNames/JPEG.html#Adobe |
| // Unknown means the data is RGB, so we don't need to perform any color conversion on it. |
| if color_transform == Some(AdobeColorTransform::Unknown) { |
| Ok(color_convert_line_null) |
| } |
| else { |
| Ok(color_convert_line_ycbcr) |
| } |
| }, |
| 4 => { |
| // http://www.sno.phy.queensu.ca/~phil/exiftool/TagNames/JPEG.html#Adobe |
| match color_transform { |
| Some(AdobeColorTransform::Unknown) => Ok(color_convert_line_cmyk), |
| Some(_) => Ok(color_convert_line_ycck), |
| None => Err(Error::Format("4 components without Adobe APP14 metadata to tell color space".to_owned())), |
| } |
| }, |
| _ => panic!(), |
| } |
| } |
| |
| fn color_convert_line_null(_data: &mut [u8], _width: usize) { |
| } |
| |
| fn color_convert_line_ycbcr(data: &mut [u8], width: usize) { |
| for i in 0 .. width { |
| let (r, g, b) = ycbcr_to_rgb(data[i * 3], data[i * 3 + 1], data[i * 3 + 2]); |
| |
| data[i * 3] = r; |
| data[i * 3 + 1] = g; |
| data[i * 3 + 2] = b; |
| } |
| } |
| |
| fn color_convert_line_ycck(data: &mut [u8], width: usize) { |
| for i in 0 .. width { |
| let (r, g, b) = ycbcr_to_rgb(data[i * 4], data[i * 4 + 1], data[i * 4 + 2]); |
| let k = data[i * 4 + 3]; |
| |
| data[i * 4] = r; |
| data[i * 4 + 1] = g; |
| data[i * 4 + 2] = b; |
| data[i * 4 + 3] = 255 - k; |
| } |
| } |
| |
| fn color_convert_line_cmyk(data: &mut [u8], width: usize) { |
| for i in 0 .. width { |
| data[i * 4] = 255 - data[i * 4]; |
| data[i * 4 + 1] = 255 - data[i * 4 + 1]; |
| data[i * 4 + 2] = 255 - data[i * 4 + 2]; |
| data[i * 4 + 3] = 255 - data[i * 4 + 3]; |
| } |
| } |
| |
| // ITU-R BT.601 |
| fn ycbcr_to_rgb(y: u8, cb: u8, cr: u8) -> (u8, u8, u8) { |
| let y = y as f32; |
| let cb = cb as f32 - 128.0; |
| let cr = cr as f32 - 128.0; |
| |
| let r = y + 1.40200 * cr; |
| let g = y - 0.34414 * cb - 0.71414 * cr; |
| let b = y + 1.77200 * cb; |
| |
| (clamp((r + 0.5) as i32, 0, 255) as u8, |
| clamp((g + 0.5) as i32, 0, 255) as u8, |
| clamp((b + 0.5) as i32, 0, 255) as u8) |
| } |
| |
| fn clamp<T: PartialOrd>(value: T, min: T, max: T) -> T { |
| if value < min { return min; } |
| if value > max { return max; } |
| value |
| } |
