Guard against negative shift in jbig2 huffman initialization

Depending on the code table, it's possible to have the largest PREFLEN
value in the huffman table to be > 32. This will, potentially, cause the
calcuation of ((FIRSTCODE[i - 1] + LENCOUNT[i - 1]) << 1 to overflow the
int value and cause a negative shift.

This Cl checks the shift value and failes the initialization if we would
shift a negative value.

Bug: chromium:709781
Change-Id: Ia165a01ba9412e31c5e5a43717d415fcb42eafe5
Reviewed-on: https://pdfium-review.googlesource.com/3990
Reviewed-by: Lei Zhang <thestig@chromium.org>
Reviewed-by: Nicolás Peña <npm@chromium.org>
Commit-Queue: dsinclair <dsinclair@chromium.org>

0 files changed, 0 insertions, 0 deletions