these unused includes were identifier by clang-include-cleaner. after
auditing these source files, all of the reports have been confirmed.
please note, because quite a few source files relied on
`utils/to_string.hh` to pull in the specialization of
`fmt::formatter<std::optional<T>>`, after removing
`#include <fmt/std.h>` from `utils/to_string.hh`, we have to
include `fmt/std.h` directly.
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Instead of lengthy blurbs, switch to single-line, machine-readable
standardized (https://spdx.dev) license identifiers. The Linux kernel
switched long ago, so there is strong precedent.
Three cases are handled: AGPL-only, Apache-only, and dual licensed.
For the latter case, I chose (AGPL-3.0-or-later and Apache-2.0),
reasoning that our changes are extensive enough to apply our license.
The changes we applied mechanically with a script, except to
licenses/README.md.
Closes#9937
Manipulating fragmented views is costlier that manipulating contiguous views,
so let's detect the common situation when the fragmented view is actually
contiguous underneath, and make use of that.
Note: this optimization is only useful for big types. For trivial types,
validation usually only checks the size of the view.
This will allow us to easily get rid of linearizations when validating
collections and tuples, because the helpers used in validate_aux() already
have FragmentedView overloads.
Add a function to validate fragmented buffers. We validate
each buffer with SIMD-optimized validate_partial(), then
collect the codepoint that spans buffer boundaries (if any)
in a temporary buffer, validate that too, and continue.
Add new validate_with_error_position function
which returns -1 if data is a valid UTF-8 string
or otherwise a byte position of first invalid
character. The position is added to exception
messages of all UTF-8 parsing errors in Scylla.
validate_with_error_position is done in two
passes in order to preserve the same performance
in common case when the string is valid.
UTF-8 string is now validated by boost::locale::conv::utf_to_utf, it
actually does string conversions which is more than necessary. As
observed on Arm server, UTF-8 validation can become bottleneck under
heavy loads.
This patch introduces a brand new SIMD implementation supporting both
NEON and SSE, as well as a naive approach to handle short strings.
The naive approach is 3x faster than boost utf_to_utf, whilst SIMD
method outperforms naive approach 3x ~ 5x on Arm and x86. Details at
https://github.com/cyb70289/utf8/.
UTF-8 unit test is added to check various corner cases.
Signed-off-by: Yibo Cai <yibo.cai@arm.com>
Message-Id: <1543978498-12123-1-git-send-email-yibo.cai@arm.com>
