The relevant RFC section from
https://www.rfc-editor.org/rfc/rfc7932#section-9.2
MSKIPBYTES * 8 bits: MSKIPLEN - 1, where MSKIPLEN is
the number of metadata bytes; this field is
only present if MSKIPBYTES is positive;
otherwise, MSKIPLEN is 0 (if MSKIPBYTES is
greater than 1, and the last byte is all
zeros, then the stream should be rejected as
invalid)
So when skip_bytes is zero we need to break and
re-align bytes.
Added the relevant test case that demonstrates this from:
https://github.com/google/brotli/blob/master/tests/testdata/x.compressed
The test-case is heavily inspired by:
https://github.com/google/brotli/blob/master/tests/testdata/x.compressed.01
Or in words: A metadata meta-block containing `Y` (which should be
ignored), and then the actual data (a single `Z`). The bug used to skip
one metadata byte too few, and thus read garbage.
Each of these strings would previously rely on StringView's char const*
constructor overload, which would call __builtin_strlen on the string.
Since we now have operator ""sv, we can replace these with much simpler
versions. This opens the door to being able to remove
StringView(char const*).
No functional changes.
Using a file(GLOB) to find all the test files in a directory is an easy
hack to get things started, but has some drawbacks. Namely, if you add
a test, it won't be found again without re-running CMake. `ninja` seems
to do this automatically, but it would be nice to one day stop seeing it
rechecking our globbed directories.
The round trip compress test wants the first half of the byte buffer to
be filled with random data, and the second half to be all zeroes. The
strategy of using memset on ByteBuffer::offset_pointer confuses
__builtin_memset_chk when building with -fsanitize=undefined. It thinks
that the buffer is using inline capacity when we can prove to ourselves
pretty easily that it's not. To avoid this, just create the buffer
zeroed to start, and then fill the first half with the random data.
