unsigned char promotes to int, which can overflow when shifted left by
24 bits or more. this has been reported multiple times but then
forgotten. it's expected to be benign UB, but can trap when built with
explicit overflow catching (ubsan or similar). fix it now.
note that promotion to uint32_t is safe and portable even outside of
the assumptions usually made in musl, since either uint32_t has rank
at least unsigned int, so that no further default promotions happen,
or int is wide enough that the shift can't overflow. this is a
desirable property to have in case someone wants to reuse the code
elsewhere.
musl commit: 593caa456309714402ca4cb77c3770f4c24da9da
Obtained from: musl
We have adopted these and don't consider them 'contrib' code, so bring
them closer to style(9). This is a followon to r315467 and r351700.
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
Mainly focus on files that use BSD 3-Clause license.
The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.
Special thanks to Wind River for providing access to "The Duke of
Highlander" tool: an older (2014) run over FreeBSD tree was useful as a
starting point.
It is O(n) in the length of the haystack (big) string, and has special
cases for short needle (little) strings, of one to four bytes, to avoid
excessive overhead.
There are a small set of nearly trivial cases where the startup overhead
of the musl implementation makes it slightly slower -- for example, a 31
byte needle that matches the beginning of the haystack. It's faster for
non-trivial cases, and significantly so for inputs that trigger worst-
case behaviour of the previous implementation. As an example, in my
tests a 16K needle that matches the end of a 64K haystack is nearly
2000x faster with this implementation.
Reviewed by: bapt (earlier), ed (earlier)
Obtained from: musl (snapshot at commit c718f9fc)
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D2601
