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-- e7f892a0b9b313b434c5f9e9a2365b377204b60e by Abseil Team <absl-team@google.com>: Remove internal CaseEqual helper now that we have the equivalent absl::EqualsIgnoreCase. PiperOrigin-RevId: 225189084 -- 722af2c74766d2fe3cee13c8dc886d39aedda597 by Abseil Team <absl-team@google.com>: Add -Wno-extra-semi-stmt to silence that warning. The [-Wno-extra-semi] is already disabled in the build. This change will allow the build to remain consistent across newer versions of clang which are now issuing a new similiar warning [-Wextra-semi-stmt]: https://clang.llvm.org/docs/ReleaseNotes.html#major-new-features https://clang.llvm.org/docs/DiagnosticsReference.html#wextra-semi-stmt PiperOrigin-RevId: 225185101 -- f7fd6244b4efcf0331631a54b7b0cf5f1f691a89 by CJ Johnson <johnsoncj@google.com>: Move using directive in swap implementation PiperOrigin-RevId: 225017825 -- 3005841725df5b9cdb35c8a5319bb4c78b5dc2b7 by Abseil Team <absl-team@google.com>: Update absl/strings/CMakeLists.txt to use new functions i.e. absl_cc_(library|test) PiperOrigin-RevId: 224860689 -- eeaf7099924b182472bfea3636ef6d9a39adfc50 by CJ Johnson <johnsoncj@google.com>: Prefer public method over private for InlinedVector allocator access PiperOrigin-RevId: 224825775 -- db9d218e3ca7ab400eef97778b720cb082a03281 by Eric Fiselier <ericwf@google.com>: Take advantage of secret libc++ resize uninitialized function in string. PiperOrigin-RevId: 224817877 GitOrigin-RevId: e7f892a0b9b313b434c5f9e9a2365b377204b60e Change-Id: I051beee37ee03f0570bd2e068355ad75c8bdfcf8
72 lines
2.6 KiB
C++
72 lines
2.6 KiB
C++
//
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// Copyright 2017 The Abseil Authors.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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//
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#ifndef ABSL_STRINGS_INTERNAL_RESIZE_UNINITIALIZED_H_
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#define ABSL_STRINGS_INTERNAL_RESIZE_UNINITIALIZED_H_
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#include <string>
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#include <type_traits>
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#include <utility>
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#include "absl/base/port.h"
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#include "absl/meta/type_traits.h" // for void_t
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namespace absl {
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namespace strings_internal {
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// Is a subclass of true_type or false_type, depending on whether or not
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// T has a __resize_default_init member.
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template <typename string_type, typename = void>
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struct ResizeUninitializedTraits {
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using HasMember = std::false_type;
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static void Resize(string_type* s, size_t new_size) { s->resize(new_size); }
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};
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// __resize_default_init is provided by libc++ >= 8.0 and by Google's internal
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// ::string implementation.
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template <typename string_type>
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struct ResizeUninitializedTraits<
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string_type, absl::void_t<decltype(std::declval<string_type&>()
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.__resize_default_init(237))> > {
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using HasMember = std::true_type;
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static void Resize(string_type* s, size_t new_size) {
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s->__resize_default_init(new_size);
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}
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};
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// Returns true if the string implementation supports a resize where
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// the new characters added to the string are left untouched.
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//
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// (A better name might be "STLStringSupportsUninitializedResize", alluding to
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// the previous function.)
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template <typename string_type>
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inline constexpr bool STLStringSupportsNontrashingResize(string_type*) {
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return ResizeUninitializedTraits<string_type>::HasMember::value;
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}
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// Like str->resize(new_size), except any new characters added to "*str" as a
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// result of resizing may be left uninitialized, rather than being filled with
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// '0' bytes. Typically used when code is then going to overwrite the backing
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// store of the string with known data. Uses a Google extension to ::string.
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template <typename string_type, typename = void>
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inline void STLStringResizeUninitialized(string_type* s, size_t new_size) {
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ResizeUninitializedTraits<string_type>::Resize(s, new_size);
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}
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} // namespace strings_internal
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} // namespace absl
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#endif // ABSL_STRINGS_INTERNAL_RESIZE_UNINITIALIZED_H_
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