One-sided binary search, aka meta binary search, has been in the public
domain for decades, and has the general advantage of being constant time
in the best case, with the downside of executing at most 2*log(N)
comparisons vs classic binary search's exact log(N). There are two
scenarios in which it really shines: the first one is when operating
over non-random-access iterators, because the classic algorithm requires
knowing the container's size upfront, which adds N iterator increments
to the complexity. The second one is when traversing the container in
order, trying to fast-forward to the next value: in that case the
classic algorithm requires at least O(N*log(N)) comparisons and, for
non-random-access iterators, O(N^2) iterator increments, whereas the
one-sided version will yield O(N) operations on both counts, with a
best-case of O(log(N)) comparisons which is very common in practice.
This patch runs clang-format on all of libcxx/include and libcxx/src, in
accordance with the RFC discussed at [1]. Follow-up patches will format
the benchmarks, the test suite and remaining parts of the code. I'm
splitting this one into its own patch so the diff is a bit easier to
review.
This patch was generated with:
find libcxx/include libcxx/src -type f \
| grep -v 'module.modulemap.in' \
| grep -v 'CMakeLists.txt' \
| grep -v 'README.txt' \
| grep -v 'libcxx.imp' \
| grep -v '__config_site.in' \
| xargs clang-format -i
A Git merge driver is available in libcxx/utils/clang-format-merge-driver.sh
to help resolve merge and rebase issues across these formatting changes.
[1]: https://discourse.llvm.org/t/rfc-clang-formatting-all-of-libc-once-and-for-all
This brings most of the enable_ifs in libc++ to the same style. It also has the nice side-effect of reducing the size of names of these symbols, since the depedent return type is shorter.
Reviewed By: #libc, ldionne
Spies: ldionne, libcxx-commits
Differential Revision: https://reviews.llvm.org/D157787
POSIX allows certain macros to exist with generic names (i.e. refresh(), move(), and erase()) to exist in `curses.h` which conflict with functions found in std::filesystem, among others. This patch undefs the macros in question and adds them to LIBCPP_PUSH_MACROS and LIBCPP_POP_MACROS.
Reviewed By: #libc, philnik, ldionne
Differential Revision: https://reviews.llvm.org/D147356
This change is almost fully mechanical. The only interesting change is in `generate_feature_test_macro_components.py` to generate `_LIBCPP_STD_VER >=` instead. To avoid churn in the git-blame this commit should be added to the `.git-blame-ignore-revs` once committed.
Reviewed By: ldionne, var-const, #libc
Spies: jloser, libcxx-commits, arichardson, arphaman, wenlei
Differential Revision: https://reviews.llvm.org/D143962
This was discussed on Discord with the consensus that we should rename the macros.
Reviewed By: ldionne, Mordante, var-const, avogelsgesang, jloser, #libc
Spies: libcxx-commits
Differential Revision: https://reviews.llvm.org/D131498
When we ship LLVM 16, <ranges> won't be considered experimental anymore.
We might as well do this sooner rather than later.
Differential Revision: https://reviews.llvm.org/D132151
Also fix `ranges::stable_sort` and `ranges::inplace_merge` to support
proxy iterators now that their internal implementations can correctly
dispatch `rotate`.
Differential Revision: https://reviews.llvm.org/D130758
Avoid relying on `iterator_traits` and instead deduce the return type of
dereferencing the iterator. Additionally, add a static check to reject
iterators with incorrect `iterator_traits` at compile time.
Differential Revision: https://reviews.llvm.org/D130538
The return type was specified incorrectly for proxy iterators that
define `reference` to be a class that implicitly converts to
`value_type`. `__iter_move` would end up returning an object of type
`reference` which would then implicitly convert to `value_type`; thus,
the function will return a `value_type&&` rvalue reference to the local
temporary.
Differential Revision: https://reviews.llvm.org/D130197
Change the mechanism in `iterator_operations.h` to pass around a generic
policy tag indicating whether an internal function is being invoked from
a "classic" STL algorithm or a ranges algorithm. `IterOps` is now
a template class specialized on the policy tag.
The advantage is that this mechanism is more generic and allows defining
arbitrary conditions in a clean manner.
Also add a few more iterator functions to `IterOps`.
Differential Revision: https://reviews.llvm.org/D129390
implement `std::ranges::set_intersection` by reusing the classic `std::set_intersenction`
added unit tests
Differential Revision: https://reviews.llvm.org/D129233
