tree fc6a444cdaa1b018303fad9e1c828b8e78d7a650
parent 3d4afc9ee33ba0dd07371ed802c81a07e23affef
author Tom Sepez <tsepez@chromium.org> 1623260337 +0000
committer Pdfium LUCI CQ <pdfium-scoped@luci-project-accounts.iam.gserviceaccount.com> 1623260337 +0000

Remove some unreachable code from progressive_decoder.cpp

ProgressiveDecoder::WeightTable::Calc() runs the risk of passing a
negative length parameter to resize() if the dest_len parameter is
less than 0. Fortunately, the only caller passes m_sizeX, which is
only set to a non-zero value from device_rc.Width() at line 2172.
We know this is non-negative since we checked size_x at line 2158
priot to setting up device_rc.

Convert to a check for non-negative values, and remove the
calculations involving `base` since we know that it will be zero.
Note that Calc() is uncomfortably similar to code in CStretchEngine,
but that does not have the same issue because the size is computed
from different parameters.

Change-Id: I7cc3d8672036150691f93a55e05659dc8168e3f6
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/81710
Auto-Submit: Tom Sepez <tsepez@chromium.org>
Commit-Queue: Lei Zhang <thestig@chromium.org>
Reviewed-by: Lei Zhang <thestig@chromium.org>