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// Copyright 2017 PDFium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
// Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
#include "core/fxcrt/cfx_blockbuffer.h"
#include <algorithm>
#include <utility>
namespace {
const size_t kAllocStep = 1024 * 1024;
} // namespace
CFX_BlockBuffer::CFX_BlockBuffer()
: m_DataLength(0), m_BufferSize(0), m_StartPosition(0) {}
CFX_BlockBuffer::~CFX_BlockBuffer() {}
size_t CFX_BlockBuffer::GetAllocStep() const {
return kAllocStep;
}
std::pair<wchar_t*, size_t> CFX_BlockBuffer::GetAvailableBlock() {
if (m_BlockArray.empty())
return {nullptr, 0};
size_t realIndex = m_StartPosition + m_DataLength;
if (realIndex == m_BufferSize) {
m_BlockArray.emplace_back(FX_Alloc(wchar_t, kAllocStep));
m_BufferSize += kAllocStep;
return {m_BlockArray.back().get(), 0};
}
return {m_BlockArray[realIndex / kAllocStep].get(), realIndex % kAllocStep};
}
bool CFX_BlockBuffer::InitBuffer() {
m_BlockArray.clear();
m_BlockArray.emplace_back(FX_Alloc(wchar_t, kAllocStep));
m_BufferSize = kAllocStep;
return true;
}
void CFX_BlockBuffer::SetTextChar(size_t index, wchar_t ch) {
size_t realIndex = m_StartPosition + index;
size_t blockIndex = realIndex / kAllocStep;
if (blockIndex >= m_BlockArray.size()) {
size_t newBlocks = blockIndex - m_BlockArray.size() + 1;
do {
m_BlockArray.emplace_back(FX_Alloc(wchar_t, kAllocStep));
m_BufferSize += kAllocStep;
} while (--newBlocks);
}
wchar_t* pTextData = m_BlockArray[blockIndex].get();
pTextData[realIndex % kAllocStep] = ch;
m_DataLength = std::max(m_DataLength, index + 1);
}
void CFX_BlockBuffer::DeleteTextChars(size_t count) {
if (count == 0)
return;
if (count >= m_DataLength) {
Reset(false);
return;
}
m_DataLength -= count;
}
WideString CFX_BlockBuffer::GetTextData(size_t start, size_t length) const {
if (m_BufferSize <= m_StartPosition + 1 || length == 0)
return WideString();
size_t maybeDataLength = m_BufferSize - 1 - m_StartPosition;
if (start > maybeDataLength)
return WideString();
length = std::min(length, maybeDataLength);
if (!length)
return WideString();
WideString wsTextData;
{
// Span's lifetime must end before ReleaseBuffer() below.
pdfium::span<wchar_t> pBuf = wsTextData.GetBuffer(length);
size_t startBlock = 0;
size_t startInner = 0;
std::tie(startBlock, startInner) = TextDataIndex2BufIndex(start);
size_t endBlock = 0;
size_t endInner = 0;
std::tie(endBlock, endInner) = TextDataIndex2BufIndex(start + length);
size_t pointer = 0;
for (size_t i = startBlock; i <= endBlock; ++i) {
size_t bufferPointer = 0;
size_t copyLength = kAllocStep;
if (i == startBlock) {
copyLength -= startInner;
bufferPointer = startInner;
}
if (i == endBlock)
copyLength -= ((kAllocStep - 1) - endInner);
wchar_t* pBlockBuf = m_BlockArray[i].get();
memcpy(&pBuf[pointer], pBlockBuf + bufferPointer,
copyLength * sizeof(wchar_t));
pointer += copyLength;
}
}
wsTextData.ReleaseBuffer(length);
return wsTextData;
}
std::pair<size_t, size_t> CFX_BlockBuffer::TextDataIndex2BufIndex(
const size_t iIndex) const {
ASSERT(iIndex >= 0);
size_t realIndex = m_StartPosition + iIndex;
return {realIndex / kAllocStep, realIndex % kAllocStep};
}
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