148 lines
5.2 KiB
Rust
148 lines
5.2 KiB
Rust
//
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// Copyright (c) 2020 KAMADA Ken'ichi.
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// All rights reserved.
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//
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// Redistribution and use in source and binary forms, with or without
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// modification, are permitted provided that the following conditions
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// are met:
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// 1. Redistributions of source code must retain the above copyright
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// notice, this list of conditions and the following disclaimer.
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// 2. Redistributions in binary form must reproduce the above copyright
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// notice, this list of conditions and the following disclaimer in the
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// documentation and/or other materials provided with the distribution.
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//
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// THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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// ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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// OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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// HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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// LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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// OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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// SUCH DAMAGE.
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//
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use std::io::{BufRead, ErrorKind};
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use crate::endian::{Endian, LittleEndian};
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use crate::error::Error;
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use crate::util::{BufReadExt as _, ReadExt as _};
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// Chunk identifiers for RIFF.
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const FCC_RIFF: [u8; 4] = *b"RIFF";
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const FCC_WEBP: [u8; 4] = *b"WEBP";
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const FCC_EXIF: [u8; 4] = *b"EXIF";
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// Get the contents of the Exif chunk from a WebP file.
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pub fn get_exif_attr<R>(reader: &mut R)
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-> Result<Vec<u8>, Error> where R: BufRead {
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match get_exif_attr_sub(reader) {
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Err(Error::Io(ref e)) if e.kind() == ErrorKind::UnexpectedEof =>
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Err(Error::InvalidFormat("Broken WebP file")),
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r => r,
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}
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}
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fn get_exif_attr_sub<R>(reader: &mut R)
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-> Result<Vec<u8>, Error> where R: BufRead {
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let mut sig = [0; 12];
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reader.read_exact(&mut sig)?;
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if sig[0..4] != FCC_RIFF || sig[8..12] != FCC_WEBP {
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return Err(Error::InvalidFormat("Not a WebP file"));
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}
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let mut file_size = LittleEndian::loadu32(&sig, 4) as usize;
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file_size = file_size.checked_sub(4)
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.ok_or(Error::InvalidFormat("Invalid header file size"))?;
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// Scan the series of chunks.
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while file_size > 0 {
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file_size = file_size.checked_sub(8)
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.ok_or(Error::InvalidFormat("Chunk overflowing parent"))?;
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let mut cheader = [0; 8];
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reader.read_exact(&mut cheader)?;
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let mut size = LittleEndian::loadu32(&cheader, 4) as usize;
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file_size = file_size.checked_sub(size)
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.ok_or(Error::InvalidFormat("Chunk overflowing parent"))?;
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if cheader[0..4] == FCC_EXIF {
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let mut payload = Vec::new();
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reader.read_exact_len(&mut payload, size)?;
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return Ok(payload);
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}
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if size % 2 != 0 && file_size > 0 {
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file_size -= 1;
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size = size.checked_add(1).expect("ex-file_size - size > 0");
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}
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reader.discard_exact(size)?;
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}
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Err(Error::NotFound("WebP"))
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}
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pub fn is_webp(buf: &[u8]) -> bool {
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buf.len() >= 12 && buf[0..4] == FCC_RIFF && buf[8..12] == FCC_WEBP
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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#[test]
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fn truncated() {
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let mut data = b"RIFF\x10\0\0\0WEBPEXIF\x04\0\0\0Exif".to_vec();
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assert_eq!(get_exif_attr(&mut &data[..]).unwrap(), b"Exif");
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while let Some(_) = data.pop() {
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get_exif_attr(&mut &data[..]).unwrap_err();
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}
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}
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#[test]
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fn no_exif() {
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let data = b"RIFF\x0c\0\0\0WEBPwhat\0\0\0\0";
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assert_err_pat!(get_exif_attr(&mut &data[..]), Error::NotFound(_));
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}
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#[test]
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fn empty() {
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let data = b"RIFF\x16\0\0\0WEBPodd_\x01\0\0\0X\0EXIF\0\0\0\0";
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assert_ok!(get_exif_attr(&mut &data[..]), b"");
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}
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#[test]
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fn non_empty() {
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let data = b"RIFF\x1a\0\0\0WEBPeven\x02\0\0\0XYEXIF\x03\0\0\0abcd";
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assert_ok!(get_exif_attr(&mut &data[..]), b"abc");
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}
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#[test]
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fn read_first() {
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let data = b"RIFF\x18\0\0\0WEBPEXIF\x02\0\0\0abEXIF\x02\0\0\0cd";
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assert_ok!(get_exif_attr(&mut &data[..]), b"ab");
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}
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#[test]
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fn out_of_toplevel_chunk() {
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let data = b"RIFF\x0e\0\0\0WEBPwhat\x02\0\0\0abEXIF\x02\0\0\0cd";
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assert_err_pat!(get_exif_attr(&mut &data[..]), Error::NotFound(_));
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}
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#[test]
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fn overflowing_parent() {
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let mut data = b"RIFF\x10\0\0\0WEBPEXIF\x04\0\0\0Exif".to_vec();
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assert_eq!(get_exif_attr(&mut &data[..]).unwrap(), b"Exif");
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for x in 0x05..=0x0f {
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data[4] = x;
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assert_err_pat!(get_exif_attr(&mut &data[..]),
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Error::InvalidFormat(_));
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}
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data[4] = 0x04;
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assert_err_pat!(get_exif_attr(&mut &data[..]), Error::NotFound(_));
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}
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#[test]
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fn odd_at_last_without_padding() {
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let data = b"RIFF\x17\0\0\0WEBPwhat\0\0\0\0EXIF\x03\0\0\0abc";
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assert_ok!(get_exif_attr(&mut &data[..]), b"abc");
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}
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}
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