562889db3f
The added file contains a simple alias of an std::unordered_map that supports looking up std::string_view without incurring a copy. Bug: 349741884 Change-Id: I50ef7faa2a1c04b03d4ea9c3d9bbb26aff2c6b77 Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5676786 Reviewed-by: Colin Blundell <blundell@chromium.org> Commit-Queue: Jan Keitel <jkeitel@google.com> Reviewed-by: Dominic Battré <battre@chromium.org> Cr-Commit-Position: refs/heads/main@{#1323590}
29 lines
909 B
C++
29 lines
909 B
C++
// Copyright 2024 The Chromium Authors
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#ifndef COMPONENTS_PREFS_TRANSPARENT_UNORDERED_STRING_MAP_H_
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#define COMPONENTS_PREFS_TRANSPARENT_UNORDERED_STRING_MAP_H_
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#include <functional>
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#include <string>
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#include <string_view>
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#include <unordered_map>
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namespace internal {
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struct StringViewHasher : public std::hash<std::string_view> {
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using is_transparent = void;
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};
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} // namespace internal
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// A `std::unordered_map` from `std::string` to `ValueType` that allows
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// copy-less find for `std::string_view`.
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template <typename ValueType>
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using TransparentUnorderedStringMap =
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std::unordered_map<std::string,
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ValueType,
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internal::StringViewHasher,
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std::equal_to<>>;
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#endif // COMPONENTS_PREFS_TRANSPARENT_UNORDERED_STRING_MAP_H_
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