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use byteorder::{LittleEndian, ReadBytesExt};
use std::convert::TryFrom;
use std::io::{self, Cursor, Read, Seek, SeekFrom};
use std::marker::PhantomData;
use std::{error, fmt, mem};
use crate::color::ColorType;
use crate::error::{DecodingError, ImageError, ImageResult, UnsupportedError, UnsupportedErrorKind};
use crate::image::{self, ImageDecoder, ImageFormat};
use self::InnerDecoder::*;
use crate::bmp::BmpDecoder;
use crate::png::PngDecoder;
const PNG_SIGNATURE: [u8; 8] = [137, 80, 78, 71, 13, 10, 26, 10];
#[derive(Debug, Copy, Clone, Hash, PartialEq, Eq, PartialOrd, Ord)]
enum DecoderError {
NoEntries,
IcoEntryTooManyPlanesOrHotspot,
IcoEntryTooManyBitsPerPixelOrHotspot,
PngShorterThanHeader,
PngNotRgba,
InvalidDataSize,
ImageEntryDimensionMismatch {
format: IcoEntryImageFormat,
entry: (u16, u16),
image: (u32, u32)
},
}
impl fmt::Display for DecoderError {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
match self {
DecoderError::NoEntries =>
f.write_str("ICO directory contains no image"),
DecoderError::IcoEntryTooManyPlanesOrHotspot =>
f.write_str("ICO image entry has too many color planes or too large hotspot value"),
DecoderError::IcoEntryTooManyBitsPerPixelOrHotspot =>
f.write_str("ICO image entry has too many bits per pixel or too large hotspot value"),
DecoderError::PngShorterThanHeader =>
f.write_str("Entry specified a length that is shorter than PNG header!"),
DecoderError::PngNotRgba =>
f.write_str("The PNG is not in RGBA format!"),
DecoderError::InvalidDataSize =>
f.write_str("ICO image data size did not match expected size"),
DecoderError::ImageEntryDimensionMismatch { format, entry, image } =>
f.write_fmt(format_args!("Entry{:?} and {}{:?} dimensions do not match!", entry, format, image)),
}
}
}
impl From<DecoderError> for ImageError {
fn from(e: DecoderError) -> ImageError {
ImageError::Decoding(DecodingError::new(ImageFormat::Ico.into(), e))
}
}
impl error::Error for DecoderError {}
#[derive(Debug, Copy, Clone, Hash, PartialEq, Eq, PartialOrd, Ord)]
enum IcoEntryImageFormat {
Png,
Bmp,
}
impl fmt::Display for IcoEntryImageFormat {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.write_str(match self {
IcoEntryImageFormat::Png => "PNG",
IcoEntryImageFormat::Bmp => "BMP",
})
}
}
impl Into<ImageFormat> for IcoEntryImageFormat {
fn into(self) -> ImageFormat {
match self {
IcoEntryImageFormat::Png => ImageFormat::Png,
IcoEntryImageFormat::Bmp => ImageFormat::Bmp,
}
}
}
pub struct IcoDecoder<R: Read> {
selected_entry: DirEntry,
inner_decoder: InnerDecoder<R>,
}
enum InnerDecoder<R: Read> {
BMP(BmpDecoder<R>),
PNG(PngDecoder<R>),
}
#[derive(Clone, Copy, Default)]
struct DirEntry {
width: u8,
height: u8,
#[allow(unused)]
color_count: u8,
#[allow(unused)]
reserved: u8,
#[allow(unused)]
num_color_planes: u16,
bits_per_pixel: u16,
image_length: u32,
image_offset: u32,
}
impl<R: Read + Seek> IcoDecoder<R> {
pub fn new(mut r: R) -> ImageResult<IcoDecoder<R>> {
let entries = read_entries(&mut r)?;
let entry = best_entry(entries)?;
let decoder = entry.decoder(r)?;
Ok(IcoDecoder {
selected_entry: entry,
inner_decoder: decoder,
})
}
}
fn read_entries<R: Read>(r: &mut R) -> ImageResult<Vec<DirEntry>> {
let _reserved = r.read_u16::<LittleEndian>()?;
let _type = r.read_u16::<LittleEndian>()?;
let count = r.read_u16::<LittleEndian>()?;
(0..count).map(|_| read_entry(r)).collect()
}
fn read_entry<R: Read>(r: &mut R) -> ImageResult<DirEntry> {
Ok(DirEntry {
width: r.read_u8()?,
height: r.read_u8()?,
color_count: r.read_u8()?,
reserved: r.read_u8()?,
num_color_planes: {
let num = r.read_u16::<LittleEndian>()?;
if num > 256 {
return Err(DecoderError::IcoEntryTooManyPlanesOrHotspot.into());
}
num
},
bits_per_pixel: {
let num = r.read_u16::<LittleEndian>()?;
if num > 256 {
return Err(DecoderError::IcoEntryTooManyBitsPerPixelOrHotspot.into());
}
num
},
image_length: r.read_u32::<LittleEndian>()?,
image_offset: r.read_u32::<LittleEndian>()?,
})
}
fn best_entry(mut entries: Vec<DirEntry>) -> ImageResult<DirEntry> {
let mut best = entries.pop().ok_or(DecoderError::NoEntries)?;
let mut best_score = (
best.bits_per_pixel,
u32::from(best.real_width()) * u32::from(best.real_height()),
);
for entry in entries {
let score = (
entry.bits_per_pixel,
u32::from(entry.real_width()) * u32::from(entry.real_height()),
);
if score > best_score {
best = entry;
best_score = score;
}
}
Ok(best)
}
impl DirEntry {
fn real_width(&self) -> u16 {
match self.width {
0 => 256,
w => u16::from(w),
}
}
fn real_height(&self) -> u16 {
match self.height {
0 => 256,
h => u16::from(h),
}
}
fn matches_dimensions(&self, width: u32, height: u32) -> bool {
u32::from(self.real_width()) == width && u32::from(self.real_height()) == height
}
fn seek_to_start<R: Read + Seek>(&self, r: &mut R) -> ImageResult<()> {
r.seek(SeekFrom::Start(u64::from(self.image_offset)))?;
Ok(())
}
fn is_png<R: Read + Seek>(&self, r: &mut R) -> ImageResult<bool> {
self.seek_to_start(r)?;
let mut signature = [0u8; 8];
r.read_exact(&mut signature)?;
Ok(signature == PNG_SIGNATURE)
}
fn decoder<R: Read + Seek>(&self, mut r: R) -> ImageResult<InnerDecoder<R>> {
let is_png = self.is_png(&mut r)?;
self.seek_to_start(&mut r)?;
if is_png {
Ok(PNG(PngDecoder::new(r)?))
} else {
Ok(BMP(BmpDecoder::new_with_ico_format(r)?))
}
}
}
pub struct IcoReader<R>(Cursor<Vec<u8>>, PhantomData<R>);
impl<R> Read for IcoReader<R> {
fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
self.0.read(buf)
}
fn read_to_end(&mut self, buf: &mut Vec<u8>) -> io::Result<usize> {
if self.0.position() == 0 && buf.is_empty() {
mem::swap(buf, self.0.get_mut());
Ok(buf.len())
} else {
self.0.read_to_end(buf)
}
}
}
impl<'a, R: 'a + Read + Seek> ImageDecoder<'a> for IcoDecoder<R> {
type Reader = IcoReader<R>;
fn dimensions(&self) -> (u32, u32) {
match self.inner_decoder {
BMP(ref decoder) => decoder.dimensions(),
PNG(ref decoder) => decoder.dimensions(),
}
}
fn color_type(&self) -> ColorType {
match self.inner_decoder {
BMP(ref decoder) => decoder.color_type(),
PNG(ref decoder) => decoder.color_type(),
}
}
fn into_reader(self) -> ImageResult<Self::Reader> {
Ok(IcoReader(Cursor::new(image::decoder_to_vec(self)?), PhantomData))
}
fn read_image(self, buf: &mut [u8]) -> ImageResult<()> {
assert_eq!(u64::try_from(buf.len()), Ok(self.total_bytes()));
match self.inner_decoder {
PNG(decoder) => {
if self.selected_entry.image_length < PNG_SIGNATURE.len() as u32 {
return Err(DecoderError::PngShorterThanHeader.into());
}
let (width, height) = decoder.dimensions();
if !self.selected_entry.matches_dimensions(width, height) {
return Err(DecoderError::ImageEntryDimensionMismatch {
format: IcoEntryImageFormat::Png,
entry: (self.selected_entry.real_width(), self.selected_entry.real_height()),
image: (width, height)
}.into());
}
if decoder.color_type() != ColorType::Rgba8 {
return Err(DecoderError::PngNotRgba.into());
}
decoder.read_image(buf)
}
BMP(mut decoder) => {
let (width, height) = decoder.dimensions();
if !self.selected_entry.matches_dimensions(width, height) {
return Err(DecoderError::ImageEntryDimensionMismatch {
format: IcoEntryImageFormat::Bmp,
entry: (self.selected_entry.real_width(), self.selected_entry.real_height()),
image: (width, height)
}.into());
}
if decoder.color_type() != ColorType::Rgba8 {
return Err(ImageError::Unsupported(UnsupportedError::from_format_and_kind(
ImageFormat::Bmp.into(),
UnsupportedErrorKind::Color(decoder.color_type().into()),
)));
}
decoder.read_image_data(buf)?;
let r = decoder.reader();
let image_end = r.seek(SeekFrom::Current(0))?;
let data_end =
u64::from(self.selected_entry.image_offset + self.selected_entry.image_length);
let mask_row_bytes = ((width + 31) / 32) * 4;
let mask_length = u64::from(mask_row_bytes) * u64::from(height);
if data_end >= image_end + mask_length {
for y in 0..height {
let mut x = 0;
for _ in 0..mask_row_bytes {
let mask_byte = r.read_u8()?;
for bit in (0..8).rev() {
if x >= width {
break;
}
if mask_byte & (1 << bit) != 0 {
buf[((height - y - 1) * width + x) as usize * 4 + 3] = 0;
}
x += 1;
}
}
}
Ok(())
} else if data_end == image_end {
Ok(())
} else {
Err(DecoderError::InvalidDataSize.into())
}
}
}
}
}