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// Copyright 2020 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef THIRD_PARTY_BLINK_RENDERER_PLATFORM_WTF_TEXT_CHARACTER_VISITOR_H_
#define THIRD_PARTY_BLINK_RENDERER_PLATFORM_WTF_TEXT_CHARACTER_VISITOR_H_
namespace WTF {
// Visits the characters of a WTF::String, WTF::AtomicString, StringView or
// compatible type.
//
// Intended to be used with a generic lambda or other functor overloaded to
// handle either LChar* or UChar*. Reduces code duplication in many cases.
// The functor should receive a base::span<T> and should return the same type
// in both branches.
//
// Callers should ensure that characters exist (i.e. the string is not null)
// first.
//
// Example:
//
// if (string.IsNull())
// return false;
//
// return WTF::VisitCharacters(string, [&](auto chars) {
// bool contains_space = false;
// for (auto ch : chars)
// contains_space |= IsASCIISpace(ch);
// return contains_space;
// });
//
// This will instantiate the functor for both LChar (8-bit) and UChar (16-bit)
// automatically.
template <typename StringType, typename Functor>
decltype(auto) VisitCharacters(const StringType& string,
const Functor& functor) {
return string.Is8Bit() ? functor(string.Span8()) : functor(string.Span16());
}
} // namespace WTF
#endif // THIRD_PARTY_BLINK_RENDERER_PLATFORM_WTF_TEXT_CHARACTER_VISITOR_H_
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