488006d276
Add a purpose-built builder for constructing Utf16String values. It keeps ASCII storage while possible, widens to UTF-16 when needed, and can hand outline storage to Utf16StringData for direct adoption. Add AK coverage for ASCII strings, UTF-16 widening, code points, trimming, and long string construction.
120 lines
3.4 KiB
C++
120 lines
3.4 KiB
C++
/*
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* Copyright (c) 2026-present, the Ladybird developers.
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#pragma once
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#include <AK/Badge.h>
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#include <AK/Forward.h>
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#include <AK/Optional.h>
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#include <AK/Span.h>
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#include <AK/StringView.h>
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#include <AK/Types.h>
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#include <AK/Utf16View.h>
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namespace AK {
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class Utf16StringBuilder {
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public:
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static constexpr size_t inline_capacity = 256;
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class Buffer {
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public:
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Buffer() = default;
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~Buffer();
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Buffer(Buffer const&) = delete;
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Buffer(Buffer&&) = delete;
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Buffer& operator=(Buffer const&) = delete;
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Buffer& operator=(Buffer&&) = delete;
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[[nodiscard]] u8* data();
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[[nodiscard]] u8 const* data() const;
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[[nodiscard]] Bytes span() LIFETIME_BOUND;
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[[nodiscard]] ReadonlyBytes span() const LIFETIME_BOUND;
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[[nodiscard]] size_t size() const { return m_size; }
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[[nodiscard]] size_t capacity() const { return m_inline ? inline_capacity : m_outline_capacity; }
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[[nodiscard]] bool is_inline() const { return m_inline; }
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void clear();
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void resize(size_t);
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void set_size(size_t);
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void ensure_capacity(size_t);
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void append(void const*, size_t);
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struct OutlineBuffer {
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Bytes buffer;
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size_t capacity { 0 };
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};
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Optional<OutlineBuffer> leak_outline_buffer();
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private:
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void trim(size_t, bool may_discard_existing_data);
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void shrink_into_inline_buffer(size_t, bool may_discard_existing_data);
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void ensure_capacity_slowpath(size_t);
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union {
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u8 m_inline_buffer[inline_capacity];
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struct {
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u8* m_outline_buffer;
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size_t m_outline_capacity;
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};
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};
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size_t m_size { 0 };
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bool m_inline { true };
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};
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Utf16StringBuilder();
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explicit Utf16StringBuilder(size_t initial_capacity_in_code_units);
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~Utf16StringBuilder() = default;
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Utf16StringBuilder(Utf16StringBuilder const&) = delete;
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Utf16StringBuilder(Utf16StringBuilder&&) = delete;
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Utf16StringBuilder& operator=(Utf16StringBuilder const&) = delete;
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Utf16StringBuilder& operator=(Utf16StringBuilder&&) = delete;
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void append(Utf16View const&);
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void append_ascii(char);
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void append_ascii(StringView);
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void append_code_unit(char16_t);
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void append_code_point(u32);
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void append_repeated_ascii(char, size_t);
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void append_repeated(Utf16View const&, size_t);
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[[nodiscard]] Utf16String to_string();
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[[nodiscard]] Utf16View view() const;
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[[nodiscard]] size_t length_in_code_units() const;
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[[nodiscard]] bool is_empty() const { return length_in_code_units() == 0; }
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void trim(size_t count_in_code_units);
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void clear();
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Optional<Buffer::OutlineBuffer> leak_buffer_for_string_construction(Badge<Detail::Utf16StringData>)
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{
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return leak_buffer_for_string_construction();
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}
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private:
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void initialize_buffer(size_t capacity_in_code_units);
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void will_append(size_t size_in_bytes);
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void ensure_storage_is_utf16();
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Optional<Buffer::OutlineBuffer> leak_buffer_for_string_construction();
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[[nodiscard]] u8* data();
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[[nodiscard]] u8 const* data() const;
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[[nodiscard]] size_t length_in_bytes() const;
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Buffer m_buffer;
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bool m_is_ascii { true };
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};
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}
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#if USING_AK_GLOBALLY
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using AK::Utf16StringBuilder;
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#endif
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