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#![no_main]
extern crate libfuzzer_sys;
use libfuzzer_sys::fuzz_target;
extern crate png;
use std::io::{BufRead, Read, Result};
/// A reader that reads at most `n` bytes.
struct SmalBuf<R: BufRead> {
inner: R,
cap: usize,
}
impl<R: BufRead> SmalBuf<R> {
fn new(inner: R, cap: usize) -> Self {
SmalBuf { inner, cap }
}
}
impl<R: BufRead> Read for SmalBuf<R> {
fn read(&mut self, buf: &mut [u8]) -> Result<usize> {
let len = buf.len().min(self.cap);
self.inner.read(&mut buf[..len])
}
}
impl<R: BufRead> BufRead for SmalBuf<R> {
fn fill_buf(&mut self) -> Result<&[u8]> {
let buf = self.inner.fill_buf()?;
let len = buf.len().min(self.cap);
Ok(&buf[..len])
}
fn consume(&mut self, amt: usize) {
assert!(amt <= self.cap);
self.inner.consume(amt)
}
}
fuzz_target!(|data: &[u8]| {
// Small limits, we don't need them hopefully.
let limits = png::Limits { bytes: 1 << 16 };
let reference = png::Decoder::new_with_limits(data, limits);
let smal = png::Decoder::new_with_limits(SmalBuf::new(data, 1), limits);
let _ = png_compare(reference, smal);
});
#[inline(always)]
fn png_compare<R: BufRead, S: BufRead>(reference: png::Decoder<R>, smal: png::Decoder<S>)
-> std::result::Result<png::OutputInfo, ()>
{
let mut smal = Some(smal);
let (info, mut reference) = reference.read_info().map_err(|_| {
assert!(smal.take().unwrap().read_info().is_err());
})?;
let (sinfo, mut smal) = smal.take().unwrap().read_info().expect("Deviation");
assert_eq!(info, sinfo);
if info.buffer_size() > 5_000_000 {
return Err(());
}
let mut ref_data = vec![0; info.buffer_size()];
let mut smal_data = vec![0; info.buffer_size()];
let _rref = reference.next_frame(&mut ref_data);
let _rsmal = smal.next_frame(&mut smal_data);
assert_eq!(smal_data, ref_data);
return Ok(info);
}