Crash on compressing with interlacing enabled

[bpbp-boop]

oxipng is crashing with the uploaded file:
https://cloud.githubusercontent.com/assets/322387/15561653/543759a2-233b-11e6-8624-5809f6551000.png

oxipng -o 4 -i 1 --strip safe 1x1.png

Processing: 1x1.png
    1x1 pixels, PNG format
    2x8 bits/pixel, GrayscaleAlpha
    IDAT size = 11 bytes
    File size = 68 bytes
Trying: 48 combinations
thread '<main>' panicked at 'index 2 out of range for slice of length 0', ../src/libcore/slice.rs:527
stack backtrace:
   1:     0x7f1403ffb060 - sys::backtrace::tracing::imp::write::h3675b4f0ca767761Xcv
   2:     0x7f1403ffdf1b - panicking::default_handler::_$u7b$$u7b$closure$u7d$$u7d$::closure.44519
   3:     0x7f1403ffdb88 - panicking::default_handler::h18faf4fbd296d909lSz
   4:     0x7f1403feee4c - sys_common::unwind::begin_unwind_inner::hfb5d07d6e405c6bbg1t
   5:     0x7f1403fef298 - sys_common::unwind::begin_unwind_fmt::h8b491a76ae84af35m0t
   6:     0x7f1403ffa4d1 - rust_begin_unwind
   7:     0x7f140402d4af - panicking::panic_fmt::h98b8cbb286f5298alcM
   8:     0x7f140402d723 - slice::slice_index_len_fail::hc4dead8ea7162edaCWP
   9:     0x7f1403f37959 - png::filter_line::h754e21cc4a65cb1cHWb
  10:     0x7f1403f2576e - png::PngData::filter_image::h279709035897e51bJkb
  11:     0x7f1403f1d9fb - optimize_png::h380f5a051c02ba65L0c
  12:     0x7f1403f195a3 - optimize::ha508f8c49b7cb7eb8Oc
  13:     0x7f1403f138a9 - handle_optimization::h785d9e26eeb741aftja
  14:     0x7f1403f0c8ab - main::h2ac802ddff177ad7yaa
  15:     0x7f1403ffd7e4 - sys_common::unwind::try::try_fn::h14622312129452522850
  16:     0x7f1403ffa45b - __rust_try
  17:     0x7f1403ffd27b - rt::lang_start::h0ba42f7a8c46a626rKz
  18:     0x7f140311aeac - __libc_start_main
  19:     0x7f1403f09e58 - <unknown>

It's OK with just oxipng -o 4 --strip safe 1x1.png though. I've got some other crashes with different images as well, would you like separate bug reports for those as well?

[shssoichiro]

Thanks for the bug report! I'll take a look at this image and see where the issue is being thrown. Thanks for the backtrace as well.

If the other images are also crashing with -i 1, you can add them onto this issue (since the crashes are probably related). If the other images are crashing without interlacing, then please open a separate issue for them.

[shssoichiro]

I'm pushing a fix for this issue. If you still experience issues on any images with the new version, you can either comment on this issue or open a new issue with the images that are experiencing problems. Thanks!