Initial vendor packages

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

1 files changed, 522 insertions, 0 deletions

diff --git a/vendor/gif/src/reader/mod.rs b/vendor/gif/src/reader/mod.rs
new file mode 100644
index 0000000..a453e79
--- /dev/null
+++ b/vendor/gif/src/reader/mod.rs
@@ -0,0 +1,522 @@
+use std::borrow::Cow;
+use std::io;
+use std::cmp;
+use std::mem;
+use std::iter;
+use std::io::prelude::*;
+
+use crate::common::{Block, Frame};
+
+mod decoder;
+pub use self::decoder::{
+    PLTE_CHANNELS, StreamingDecoder, Decoded, DecodingError, DecodingFormatError, Extensions,
+    Version
+};
+
+const N_CHANNELS: usize = 4;
+
+/// Output mode for the image data
+#[derive(Clone, Copy, Debug, PartialEq)]
+#[repr(u8)]
+pub enum ColorOutput {
+    /// The decoder expands the image data to 32bit RGBA.
+    /// This affects:
+    ///
+    ///  - The buffer buffer of the `Frame` returned by `Decoder::read_next_frame`.
+    ///  - `Decoder::fill_buffer`, `Decoder::buffer_size` and `Decoder::line_length`.
+    RGBA = 0,
+    /// The decoder returns the raw indexed data.
+    Indexed = 1,
+}
+
+#[derive(Clone, Debug)]
+/// Memory limit in bytes. `MemoryLimit(0)` means
+/// that there is no memory limit set.
+pub struct MemoryLimit(pub u32);
+
+impl MemoryLimit {
+    /// Enforce no memory limit.
+    ///
+    /// If you intend to process images from unknown origins this is a potentially dangerous
+    /// constant to use, as your program could be vulnerable to decompression bombs. That is,
+    /// malicious images crafted specifically to require an enormous amount of memory to process
+    /// while having a disproportionately small file size.
+    ///
+    /// The risks for modern machines are a bit smaller as the dimensions of each frame can not
+    /// exceed `u32::MAX` (~4Gb) but this is still a significant amount of memory.
+    pub const NONE: MemoryLimit = MemoryLimit(0);
+
+    fn buffer_size(&self, color: ColorOutput, width: u16, height: u16) -> Option<usize> {
+        let pixels = u32::from(width) * u32::from(height);
+
+        let bytes_per_pixel = match color {
+            ColorOutput::Indexed => 1,
+            ColorOutput::RGBA => 4,
+        };
+
+        if self.0 > 0 && pixels > self.0 / bytes_per_pixel {
+            None
+        } else {
+            Some(pixels as usize * bytes_per_pixel as usize)
+        }
+    }
+}
+
+/// Options for opening a GIF decoder.
+#[derive(Clone, Debug)]
+pub struct DecodeOptions {
+    memory_limit: MemoryLimit,
+    color_output: ColorOutput,
+    check_frame_consistency: bool,
+    check_for_end_code: bool,
+    allow_unknown_blocks: bool,
+}
+
+impl DecodeOptions {
+    /// Creates a new decoder builder
+    pub fn new() -> DecodeOptions {
+        DecodeOptions {
+            memory_limit: MemoryLimit(50_000_000), // 50 MB
+            color_output: ColorOutput::Indexed,
+            check_frame_consistency: false,
+            check_for_end_code: false,
+            allow_unknown_blocks: false,
+        }
+    }
+
+    /// Configure how color data is decoded.
+    pub fn set_color_output(&mut self, color: ColorOutput) {
+        self.color_output = color;
+    }
+
+    /// Configure a memory limit for decoding.
+    pub fn set_memory_limit(&mut self, limit: MemoryLimit) {
+        self.memory_limit = limit;
+    }
+
+    /// Configure if frames must be within the screen descriptor.
+    ///
+    /// The default is `false`.
+    ///
+    /// When turned on, all frame descriptors being read must fit within the screen descriptor or
+    /// otherwise an error is returned and the stream left in an unspecified state.
+    ///
+    /// When turned off, frames may be arbitrarily larger or offset in relation to the screen. Many
+    /// other decoder libraries handle this in highly divergent ways. This moves all checks to the
+    /// caller, for example to emulate a specific style.
+    pub fn check_frame_consistency(&mut self, check: bool) {
+        self.check_frame_consistency = check;
+    }
+
+    /// Configure if LZW encoded blocks must end with a marker end code.
+    ///
+    /// The default is `false`.
+    ///
+    /// When turned on, all image data blocks—which are LZW encoded—must contain a special bit
+    /// sequence signalling the end of the data. LZW processing terminates when this code is
+    /// encountered. The specification states that it must be the last code output by the encoder
+    /// for an image.
+    ///
+    /// When turned off then image data blocks can simply end. Note that this might silently ignore
+    /// some bits of the last or second to last byte.
+    pub fn check_lzw_end_code(&mut self, check: bool) {
+        self.check_for_end_code = check;
+    }
+
+    /// Configure if unknown blocks are allowed to be decoded.
+    ///
+    /// The default is `false`.
+    ///
+    /// When turned on, the decoder will allow unknown blocks to be in the
+    /// `BlockStart` position.
+    ///
+    /// When turned off, decoded block starts must mark an `Image`, `Extension`,
+    /// or `Trailer` block. Otherwise, the decoded image will return an error.
+    /// If an unknown block error is returned from decoding, enabling this
+    /// setting may allow for a further state of decoding on the next attempt.
+    pub fn allow_unknown_blocks(&mut self, check: bool) {
+        self.allow_unknown_blocks = check;
+    }
+
+    /// Reads the logical screen descriptor including the global color palette
+    ///
+    /// Returns a `Decoder`. All decoder configuration has to be done beforehand.
+    pub fn read_info<R: Read>(self, r: R) -> Result<Decoder<R>, DecodingError> {
+        Decoder::with_no_init(r, StreamingDecoder::with_options(&self), self).init()
+    }
+}
+
+struct ReadDecoder<R: Read> {
+    reader: io::BufReader<R>,
+    decoder: StreamingDecoder,
+    at_eof: bool
+}
+
+impl<R: Read> ReadDecoder<R> {
+    fn decode_next(&mut self) -> Result<Option<Decoded>, DecodingError> {
+        while !self.at_eof {
+            let (consumed, result) = {
+                let buf = self.reader.fill_buf()?;
+                if buf.len() == 0 {
+                    return Err(DecodingError::format(
+                        "unexpected EOF"
+                    ))
+                }
+                self.decoder.update(buf)?
+            };
+            self.reader.consume(consumed);
+            match result {
+                Decoded::Nothing => (),
+                Decoded::BlockStart(Block::Trailer) => {
+                    self.at_eof = true
+                },
+                result => return Ok(unsafe{
+                    // FIXME: #6393
+                    Some(mem::transmute::<Decoded, Decoded>(result))
+                }),
+            }
+        }
+        Ok(None)
+    }
+}
+
+#[allow(dead_code)]
+/// GIF decoder
+pub struct Decoder<R: Read> {
+    decoder: ReadDecoder<R>,
+    color_output: ColorOutput,
+    memory_limit: MemoryLimit,
+    bg_color: Option<u8>,
+    global_palette: Option<Vec<u8>>,
+    current_frame: Frame<'static>,
+    buffer: Vec<u8>,
+}
+
+impl<R> Decoder<R> where R: Read {
+    /// Create a new decoder with default options.
+    pub fn new(reader: R) -> Result<Self, DecodingError> {
+        DecodeOptions::new().read_info(reader)
+    }
+
+    /// Return a builder that allows configuring limits etc.
+    pub fn build() -> DecodeOptions {
+        DecodeOptions::new()
+    }
+
+    fn with_no_init(reader: R, decoder: StreamingDecoder, options: DecodeOptions) -> Decoder<R> {
+        Decoder {
+            decoder: ReadDecoder {
+                reader: io::BufReader::new(reader),
+                decoder,
+                at_eof: false
+            },
+            bg_color: None,
+            global_palette: None,
+            buffer: Vec::with_capacity(32),
+            color_output: options.color_output,
+            memory_limit: options.memory_limit,
+            current_frame: Frame::default(),
+        }
+    }
+    
+    fn init(mut self) -> Result<Self, DecodingError> {
+        loop {
+            match self.decoder.decode_next()? {
+                Some(Decoded::BackgroundColor(bg_color)) => {
+                    self.bg_color = Some(bg_color)
+                }
+                Some(Decoded::GlobalPalette(palette)) => {
+                    self.global_palette = if palette.len() > 0 {
+                        Some(palette)
+                    } else {
+                        None
+                    };
+                    break
+                },
+                Some(_) => {
+                    // Unreachable since this loop exists after the global
+                    // palette has been read.
+                    unreachable!()
+                },
+                None => return Err(DecodingError::format(
+                    "file does not contain any image data"
+                ))
+            }
+        }
+        // If the background color is invalid, ignore it
+        if let Some(ref palette) = self.global_palette {
+            if self.bg_color.unwrap_or(0) as usize >= (palette.len() / PLTE_CHANNELS) {
+                self.bg_color = None;
+            }
+        }
+        Ok(self)
+    }
+    
+    /// Returns the next frame info
+    pub fn next_frame_info(&mut self) -> Result<Option<&Frame<'static>>, DecodingError> {
+        if !self.buffer.is_empty() {
+            // FIXME: Warn about discarding data?
+            self.buffer.clear();
+        }
+
+        loop {
+            match self.decoder.decode_next()? {
+                Some(Decoded::Frame(frame)) => {
+                    self.current_frame = frame.clone();
+                    if frame.palette.is_none() && self.global_palette.is_none() {
+                        return Err(DecodingError::format(
+                            "no color table available for current frame"
+                        ))
+                    }
+                    break
+                },
+                Some(_) => (),
+                None => return Ok(None)
+                
+            }
+        }
+        Ok(Some(&self.current_frame))
+    }
+
+    /// Reads the next frame from the image.
+    ///
+    /// Do not call `Self::next_frame_info` beforehand.
+    /// Deinterlaces the result.
+    pub fn read_next_frame(&mut self) -> Result<Option<&Frame<'static>>, DecodingError> {
+        if let Some(frame) = self.next_frame_info()? {
+            let (width, height) = (frame.width, frame.height);
+            let pixel_bytes = self.memory_limit
+                .buffer_size(self.color_output, width, height)
+                .ok_or_else(|| {
+                    DecodingError::format("image is too large to decode")
+                })?;
+
+            debug_assert_eq!(
+                pixel_bytes, self.buffer_size(),
+                "Checked computation diverges from required buffer size"
+            );
+
+            let mut vec = vec![0; pixel_bytes];
+            self.read_into_buffer(&mut vec)?;
+            self.current_frame.buffer = Cow::Owned(vec);
+            self.current_frame.interlaced = false;
+            Ok(Some(&self.current_frame))
+        } else {
+            Ok(None)
+        }
+    }
+
+    /// Reads the data of the current frame into a pre-allocated buffer.
+    ///
+    /// `Self::next_frame_info` needs to be called beforehand.
+    /// The length of `buf` must be at least `Self::buffer_size`.
+    /// Deinterlaces the result.
+    pub fn read_into_buffer(&mut self, buf: &mut [u8]) -> Result<(), DecodingError> {
+        if self.current_frame.interlaced {
+            let width = self.line_length();
+            let height = self.current_frame.height as usize;
+            for row in (InterlaceIterator { len: height, next: 0, pass: 0 }) {
+                if !self.fill_buffer(&mut buf[row*width..][..width])? {
+                    return Err(DecodingError::format("image truncated"))
+                }
+            }
+        } else {
+            let buf = &mut buf[..self.buffer_size()];
+            if !self.fill_buffer(buf)? {
+                return Err(DecodingError::format("image truncated"))
+            }
+        };
+        Ok(())
+    }
+
+    /// Reads data of the current frame into a pre-allocated buffer until the buffer has been
+    /// filled completely.
+    ///
+    /// `Self::next_frame_info` needs to be called beforehand. Returns `true` if the supplied
+    /// buffer could be filled completely. Should not be called after `false` had been returned.
+    pub fn fill_buffer(&mut self, mut buf: &mut [u8]) -> Result<bool, DecodingError> {
+        use self::ColorOutput::*;
+        const PLTE_CHANNELS: usize = 3;
+        macro_rules! handle_data(
+            ($data:expr) => {
+                match self.color_output {
+                    RGBA => {
+                        let transparent = self.current_frame.transparent;
+                        let palette: &[u8] = match self.current_frame.palette {
+                            Some(ref table) => &*table,
+                            None => &*self.global_palette.as_ref().unwrap(),
+                        };
+                        let len = cmp::min(buf.len()/N_CHANNELS, $data.len());
+                        for (rgba, &idx) in buf[..len*N_CHANNELS].chunks_mut(N_CHANNELS).zip($data.iter()) {
+                            let plte_offset = PLTE_CHANNELS * idx as usize;
+                            if palette.len() >= plte_offset + PLTE_CHANNELS {
+                                let colors = &palette[plte_offset..];
+                                rgba[0] = colors[0];
+                                rgba[1] = colors[1];
+                                rgba[2] = colors[2];
+                                rgba[3] = if let Some(t) = transparent {
+                                    if t == idx { 0x00 } else { 0xFF }
+                                } else {
+                                    0xFF
+                                }
+                            }
+                        }
+                        (len, N_CHANNELS)
+                    },
+                    Indexed => {
+                        let len = cmp::min(buf.len(), $data.len());
+                        buf[..len].copy_from_slice(&$data[..len]);
+                        (len, 1)
+                    }
+                }
+            }
+        );
+        let buf_len = self.buffer.len();
+        if buf_len > 0 {
+            let (len, channels) = handle_data!(&self.buffer);
+            let _ = self.buffer.drain(..len);
+            buf = &mut buf[len*channels..];
+            if buf.len() == 0 {
+                return Ok(true)
+            }
+        }
+        loop {
+            match self.decoder.decode_next()? {
+                Some(Decoded::Data(data)) => {
+                    let (len, channels) = handle_data!(data);
+                    buf = &mut buf[len*channels..]; // shorten buf
+                    if buf.len() > 0 {
+                        continue
+                    } else if len < data.len() {
+                        self.buffer.extend_from_slice(&data[len..]);
+                    }
+                    return Ok(true)
+                },
+                Some(_) => return Ok(false), // make sure that no important result is missed
+                None => return Ok(false)
+                
+            }
+        }
+    }
+    
+    /// Output buffer size
+    pub fn buffer_size(&self) -> usize {
+        self.line_length() * self.current_frame.height as usize
+    }
+    
+    /// Line length of the current frame
+    pub fn line_length(&self) -> usize {
+        use self::ColorOutput::*;
+        match self.color_output {
+            RGBA => self.current_frame.width as usize * N_CHANNELS,
+            Indexed => self.current_frame.width as usize
+        }
+    }
+    
+    /// Returns the color palette relevant for the current (next) frame
+    pub fn palette(&self) -> Result<&[u8], DecodingError> {
+        // TODO prevent planic
+        Ok(match self.current_frame.palette {
+            Some(ref table) => &*table,
+            None => &*self.global_palette.as_ref().ok_or(DecodingError::format(
+                "no color table available for current frame"
+            ))?,
+        })
+    }
+    
+    /// The global color palette
+    pub fn global_palette(&self) -> Option<&[u8]> {
+        self.global_palette.as_ref().map(|v| &**v)
+    }
+
+    /// Width of the image
+    pub fn width(&self) -> u16 {
+        self.decoder.decoder.width()
+    }
+
+    /// Height of the image
+    pub fn height(&self) -> u16 {
+        self.decoder.decoder.height()
+    }
+
+    /// Index of the background color in the global palette
+    pub fn bg_color(&self) -> Option<usize> {
+        self.bg_color.map(|v| v as usize)
+    }
+}
+
+struct InterlaceIterator {
+    len: usize,
+    next: usize,
+    pass: usize
+}
+
+impl iter::Iterator for InterlaceIterator {
+    type Item = usize;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        if self.len == 0 || self.pass > 3 {
+            return None
+        }
+        let mut next = self.next + [8, 8, 4, 2][self.pass];
+        while next >= self.len {
+            next = [4, 2, 1, 0][self.pass];
+            self.pass += 1;
+        }
+        mem::swap(&mut next, &mut self.next);
+        Some(next)
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use std::fs::File;
+
+    use super::{Decoder, InterlaceIterator};
+    
+    #[test]
+    fn test_simple_indexed() {
+        let mut decoder = Decoder::new(File::open("tests/samples/sample_1.gif").unwrap()).unwrap();
+        let frame = decoder.read_next_frame().unwrap().unwrap();
+        assert_eq!(&*frame.buffer, &[
+            1, 1, 1, 1, 1, 2, 2, 2, 2, 2,
+            1, 1, 1, 1, 1, 2, 2, 2, 2, 2,
+            1, 1, 1, 1, 1, 2, 2, 2, 2, 2,
+            1, 1, 1, 0, 0, 0, 0, 2, 2, 2,
+            1, 1, 1, 0, 0, 0, 0, 2, 2, 2,
+            2, 2, 2, 0, 0, 0, 0, 1, 1, 1,
+            2, 2, 2, 0, 0, 0, 0, 1, 1, 1,
+            2, 2, 2, 2, 2, 1, 1, 1, 1, 1,
+            2, 2, 2, 2, 2, 1, 1, 1, 1, 1,
+            2, 2, 2, 2, 2, 1, 1, 1, 1, 1
+        ][..])
+    }
+
+    #[test]
+    fn test_interlace_iterator() {
+        for &(len, expect) in &[
+            (0, &[][..]),
+            (1, &[0][..]),
+            (2, &[0, 1][..]),
+            (3, &[0, 2, 1][..]),
+            (4, &[0, 2, 1, 3][..]),
+            (5, &[0, 4, 2, 1, 3][..]),
+            (6, &[0, 4, 2, 1, 3, 5][..]),
+            (7, &[0, 4, 2, 6, 1, 3, 5][..]),
+            (8, &[0, 4, 2, 6, 1, 3, 5, 7][..]),
+            (9, &[0, 8, 4, 2, 6, 1, 3, 5, 7][..]),
+            (10, &[0, 8, 4, 2, 6, 1, 3, 5, 7, 9][..]),
+            (11, &[0, 8, 4, 2, 6, 10, 1, 3, 5, 7, 9][..]),
+            (12, &[0, 8, 4, 2, 6, 10, 1, 3, 5, 7, 9, 11][..]),
+            (13, &[0, 8, 4, 12, 2, 6, 10, 1, 3, 5, 7, 9, 11][..]),
+            (14, &[0, 8, 4, 12, 2, 6, 10, 1, 3, 5, 7, 9, 11, 13][..]),
+            (15, &[0, 8, 4, 12, 2, 6, 10, 14, 1, 3, 5, 7, 9, 11, 13][..]),
+            (16, &[0, 8, 4, 12, 2, 6, 10, 14, 1, 3, 5, 7, 9, 11, 13, 15][..]),
+            (17, &[0, 8, 16, 4, 12, 2, 6, 10, 14, 1, 3, 5, 7, 9, 11, 13, 15][..]),
+        ] {
+            let iter = InterlaceIterator { len: len, next: 0, pass: 0 };
+            let lines = iter.collect::<Vec<_>>();
+            assert_eq!(lines, expect);
+        }
+    }
+}