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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_seekablestreamproxy.h"
#if defined(OS_WIN)
#include <io.h>
#endif
#include <algorithm>
#include <limits>
#include <memory>
#include <utility>
#include <vector>
#include "build/build_config.h"
#include "core/fxcrt/fx_codepage.h"
#include "core/fxcrt/fx_extension.h"
#include "core/fxcrt/fx_memory_wrappers.h"
#include "core/fxcrt/fx_safe_types.h"
#include "third_party/base/stl_util.h"
namespace {
// Returns {src bytes consumed, dst chars produced}.
// Invalid sequences are silently not output.
std::pair<size_t, size_t> UTF8Decode(pdfium::span<const uint8_t> pSrc,
pdfium::span<wchar_t> pDst) {
ASSERT(!pDst.empty());
uint32_t dwCode = 0;
int32_t iPending = 0;
size_t iSrcNum = 0;
size_t iDstNum = 0;
for (size_t iIndex = 0; iIndex < pSrc.size() && iDstNum < pDst.size();
++iIndex) {
++iSrcNum;
uint8_t byte = pSrc[iIndex];
if (byte < 0x80) {
iPending = 0;
pDst[iDstNum++] = byte;
} else if (byte < 0xc0) {
if (iPending < 1)
continue;
dwCode = dwCode << 6;
dwCode |= (byte & 0x3f);
--iPending;
if (iPending == 0)
pDst[iDstNum++] = dwCode;
} else if (byte < 0xe0) {
iPending = 1;
dwCode = (byte & 0x1f);
} else if (byte < 0xf0) {
iPending = 2;
dwCode = (byte & 0x0f);
} else if (byte < 0xf8) {
iPending = 3;
dwCode = (byte & 0x07);
} else if (byte < 0xfc) {
iPending = 4;
dwCode = (byte & 0x03);
} else if (byte < 0xfe) {
iPending = 5;
dwCode = (byte & 0x01);
}
}
return {iSrcNum, iDstNum};
}
#if defined(WCHAR_T_IS_UTF32)
static_assert(sizeof(wchar_t) > 2, "wchar_t is too small");
void UTF16ToWChar(void* pBuffer, size_t iLength) {
ASSERT(pBuffer);
ASSERT(iLength > 0);
uint16_t* pSrc = static_cast<uint16_t*>(pBuffer);
wchar_t* pDst = static_cast<wchar_t*>(pBuffer);
// Perform self-intersecting copy in reverse order.
for (size_t i = iLength; i > 0; --i)
pDst[i - 1] = static_cast<wchar_t>(pSrc[i - 1]);
}
#endif // defined(WCHAR_T_IS_UTF32)
void SwapByteOrder(uint16_t* pStr, size_t iLength) {
while (iLength-- > 0) {
uint16_t wch = *pStr;
*pStr++ = (wch >> 8) | (wch << 8);
}
}
} // namespace
#define BOM_UTF8_MASK 0x00FFFFFF
#define BOM_UTF8 0x00BFBBEF
#define BOM_UTF16_MASK 0x0000FFFF
#define BOM_UTF16_BE 0x0000FFFE
#define BOM_UTF16_LE 0x0000FEFF
CFX_SeekableStreamProxy::CFX_SeekableStreamProxy(
const RetainPtr<IFX_SeekableReadStream>& stream)
: m_wCodePage(FX_CODEPAGE_DefANSI),
m_wBOMLength(0),
m_iPosition(0),
m_pStream(stream) {
ASSERT(m_pStream);
Seek(From::Begin, 0);
uint32_t bom = 0;
ReadData(reinterpret_cast<uint8_t*>(&bom), 3);
bom &= BOM_UTF8_MASK;
if (bom == BOM_UTF8) {
m_wBOMLength = 3;
m_wCodePage = FX_CODEPAGE_UTF8;
} else {
bom &= BOM_UTF16_MASK;
if (bom == BOM_UTF16_BE) {
m_wBOMLength = 2;
m_wCodePage = FX_CODEPAGE_UTF16BE;
} else if (bom == BOM_UTF16_LE) {
m_wBOMLength = 2;
m_wCodePage = FX_CODEPAGE_UTF16LE;
} else {
m_wBOMLength = 0;
m_wCodePage = FXSYS_GetACP();
}
}
Seek(From::Begin, static_cast<FX_FILESIZE>(m_wBOMLength));
}
CFX_SeekableStreamProxy::~CFX_SeekableStreamProxy() = default;
FX_FILESIZE CFX_SeekableStreamProxy::GetSize() {
return m_pStream->GetSize();
}
FX_FILESIZE CFX_SeekableStreamProxy::GetPosition() {
return m_iPosition;
}
bool CFX_SeekableStreamProxy::IsEOF() {
return m_iPosition >= GetSize();
}
void CFX_SeekableStreamProxy::Seek(From eSeek, FX_FILESIZE iOffset) {
switch (eSeek) {
case From::Begin:
m_iPosition = iOffset;
break;
case From::Current: {
FX_SAFE_FILESIZE new_pos = m_iPosition;
new_pos += iOffset;
m_iPosition =
new_pos.ValueOrDefault(std::numeric_limits<FX_FILESIZE>::max());
} break;
}
m_iPosition =
pdfium::clamp(m_iPosition, static_cast<FX_FILESIZE>(0), GetSize());
}
void CFX_SeekableStreamProxy::SetCodePage(uint16_t wCodePage) {
if (m_wBOMLength > 0)
return;
m_wCodePage = wCodePage;
}
size_t CFX_SeekableStreamProxy::ReadData(uint8_t* pBuffer, size_t iBufferSize) {
ASSERT(pBuffer);
ASSERT(iBufferSize > 0);
iBufferSize =
std::min(iBufferSize, static_cast<size_t>(GetSize() - m_iPosition));
if (iBufferSize <= 0)
return 0;
if (!m_pStream->ReadBlockAtOffset(pBuffer, m_iPosition, iBufferSize))
return 0;
FX_SAFE_FILESIZE new_pos = m_iPosition;
new_pos += iBufferSize;
m_iPosition = new_pos.ValueOrDefault(m_iPosition);
return new_pos.IsValid() ? iBufferSize : 0;
}
size_t CFX_SeekableStreamProxy::ReadBlock(wchar_t* pStr, size_t size) {
if (!pStr || size == 0)
return 0;
if (m_wCodePage == FX_CODEPAGE_UTF16LE ||
m_wCodePage == FX_CODEPAGE_UTF16BE) {
size_t iBytes = size * 2;
size_t iLen = ReadData(reinterpret_cast<uint8_t*>(pStr), iBytes);
size = iLen / 2;
if (m_wCodePage == FX_CODEPAGE_UTF16BE)
SwapByteOrder(reinterpret_cast<uint16_t*>(pStr), size);
#if defined(WCHAR_T_IS_UTF32)
if (size > 0)
UTF16ToWChar(pStr, size);
#endif
return size;
}
FX_FILESIZE pos = GetPosition();
size_t iBytes = std::min(size, static_cast<size_t>(GetSize() - pos));
if (iBytes == 0)
return 0;
std::vector<uint8_t, FxAllocAllocator<uint8_t>> buf(iBytes);
size_t iLen = ReadData(buf.data(), iBytes);
if (m_wCodePage != FX_CODEPAGE_UTF8)
return 0;
size_t iSrc;
std::tie(iSrc, size) = UTF8Decode({buf.data(), iLen}, {pStr, size});
Seek(From::Current, iSrc - iLen);
return size;
}