[libcxx-commits] [libcxx] [libc++] Optimize std::find for segmented iterators (PR #67224)

[via libcxx-commits]

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@@ -0,0 +1,56 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_FIND_SEGMENT_IF_H
+#define _LIBCPP___ALGORITHM_FIND_SEGMENT_IF_H
+
+#include <__config>
+#include <__iterator/segmented_iterator.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _SegmentedIterator, class _Pred, class _Proj>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _SegmentedIterator
+__find_segment_if(_SegmentedIterator __first, _SegmentedIterator __last, _Pred __pred, _Proj __proj) {
+  using _Traits = __segmented_iterator_traits<_SegmentedIterator>;
+
+  auto __sfirst = _Traits::__segment(__first);
+  auto __slast  = _Traits::__segment(__last);
+
+  // We are in a single segment, so we might not be at the beginning or end
+  if (__sfirst == __slast)
+    return _Traits::__compose(__sfirst, __pred(_Traits::__local(__first), _Traits::__local(__last), __proj));
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EricWF wrote:

This is likely my failing, but the names here give me no understanding of what the traits do. Are there more descriptive names?

Specifically, `_Traits`, `__local`,

https://github.com/llvm/llvm-project/pull/67224