tree ac1547264fefb28f945d56a774ec84e9969cd6c5
parent df97b13e53d1b96151fa119e3e94db19f5df097b
author Tom Sepez <tsepez@chromium.org> 1635464172 +0000
committer Lei Zhang <thestig@chromium.org> 1635464172 +0000

[M90-LTS] Use more safe arithmetic in CFX_DIBBase

Most of the calculations are "safe" because we know that the DIB
has validated sizes before allocating a buffer, and that calculations
in terms of bytes won't overflow and will be within the buffer. But
calculations in terms of bits might create overflow in temporaries,
so use safe arithmetic there instead.

Re-arranging the order of operations thus converting to bytes first
might be one option, but we want to handle the 1 bpp case.

Test would require large images that might not be possible on
all platforms.

M90 merge issues:
  cfx_bitmapcomposer.cpp: conflicting includes, and conflicting
  declaration of dest_scan

Bug: chromium:1253399
Change-Id: I3c6c5b8b1f1bf3f429c7d377a8a84c5ab53cafd9
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/85510
Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: Tom Sepez <tsepez@chromium.org>
(cherry picked from commit a8b293732a0160d1bc1d5b0ad5744922f0f820d5)
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/86230