96 lines
4.2 KiB
C++
96 lines
4.2 KiB
C++
/*
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* Copyright (C) 2010-2021 Apple Inc. All rights reserved.
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* Copyright (C) 2012 Google Inc. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
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* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
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* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
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* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#pragma once
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#include <wtf/text/StringBuilder.h>
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namespace WTF {
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// Allocate a new buffer, copying in currentCharacters (these may come from either m_string or m_buffer.
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template<typename AllocationCharacterType, typename CurrentCharacterType> void StringBuilder::allocateBuffer(const CurrentCharacterType* currentCharacters, unsigned requiredCapacity)
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{
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AllocationCharacterType* bufferCharacters;
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auto buffer = StringImpl::tryCreateUninitialized(requiredCapacity, bufferCharacters);
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if (UNLIKELY(!buffer)) {
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didOverflow();
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return;
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}
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ASSERT(!hasOverflowed());
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StringImpl::copyCharacters(bufferCharacters, currentCharacters, m_length);
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m_buffer = WTFMove(buffer);
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m_string = { };
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}
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template<typename CharacterType> void StringBuilder::reallocateBuffer(unsigned requiredCapacity)
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{
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// If the buffer has only one ref (by this StringBuilder), reallocate it.
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if (m_buffer) {
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m_string = { }; // Clear the string to remove the reference to m_buffer if any before checking the reference count of m_buffer.
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if (m_buffer->hasOneRef()) {
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CharacterType* bufferCharacters;
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auto buffer = StringImpl::tryReallocate(m_buffer.releaseNonNull(), requiredCapacity, bufferCharacters);
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if (UNLIKELY(!buffer)) {
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didOverflow();
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return;
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}
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m_buffer = WTFMove(*buffer);
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return;
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}
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}
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allocateBuffer<CharacterType>(characters<CharacterType>(), requiredCapacity);
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}
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// Make 'additionalLength' additional capacity be available in m_buffer, update m_string & m_length to use,
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// that capacity and return a pointer to the newly allocated storage so the caller can write characters there.
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// Returns nullptr if allocation fails, length overflows, or if total capacity is 0 so no buffer is needed.
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// The caller has the responsibility for checking that CharacterType is the type of the existing buffer.
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template<typename CharacterType> CharacterType* StringBuilder::extendBufferForAppending(unsigned requiredLength)
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{
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if (m_buffer && requiredLength <= m_buffer->length()) {
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m_string = { };
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return const_cast<CharacterType*>(m_buffer->characters<CharacterType>()) + std::exchange(m_length, requiredLength);
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}
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return extendBufferForAppendingSlowCase<CharacterType>(requiredLength);
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}
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// Shared by the other extendBuffer functions.
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template<typename CharacterType> CharacterType* StringBuilder::extendBufferForAppendingSlowCase(unsigned requiredLength)
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{
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ASSERT(!hasOverflowed());
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if (!requiredLength)
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return nullptr;
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reallocateBuffer(expandedCapacity(capacity(), requiredLength));
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if (UNLIKELY(hasOverflowed()))
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return nullptr;
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return const_cast<CharacterType*>(m_buffer->characters<CharacterType>()) + std::exchange(m_length, requiredLength);
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}
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} // namespace WTF
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