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// Copyright 2015 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 "JBig2_BitStream.h"
#include <algorithm>
#include "core/include/fpdfapi/fpdf_objects.h"
CJBig2_BitStream::CJBig2_BitStream(CPDF_StreamAcc* pSrcStream)
: m_pBuf(pSrcStream->GetData()),
m_dwLength(pSrcStream->GetSize()),
m_dwByteIdx(0),
m_dwBitIdx(0),
m_dwObjNum(pSrcStream->GetStream() ? pSrcStream->GetStream()->GetObjNum()
: 0) {
if (m_dwLength > 256 * 1024 * 1024) {
m_dwLength = 0;
m_pBuf = nullptr;
}
}
CJBig2_BitStream::~CJBig2_BitStream() {
}
int32_t CJBig2_BitStream::readNBits(FX_DWORD dwBits, FX_DWORD* dwResult) {
FX_DWORD dwBitPos = getBitPos();
if (dwBitPos > LengthInBits())
return -1;
*dwResult = 0;
if (dwBitPos + dwBits <= LengthInBits())
dwBitPos = dwBits;
else
dwBitPos = LengthInBits() - dwBitPos;
for (; dwBitPos > 0; --dwBitPos) {
*dwResult =
(*dwResult << 1) | ((m_pBuf[m_dwByteIdx] >> (7 - m_dwBitIdx)) & 0x01);
AdvanceBit();
}
return 0;
}
int32_t CJBig2_BitStream::readNBits(FX_DWORD dwBits, int32_t* nResult) {
FX_DWORD dwBitPos = getBitPos();
if (dwBitPos > LengthInBits())
return -1;
*nResult = 0;
if (dwBitPos + dwBits <= LengthInBits())
dwBitPos = dwBits;
else
dwBitPos = LengthInBits() - dwBitPos;
for (; dwBitPos > 0; --dwBitPos) {
*nResult =
(*nResult << 1) | ((m_pBuf[m_dwByteIdx] >> (7 - m_dwBitIdx)) & 0x01);
AdvanceBit();
}
return 0;
}
int32_t CJBig2_BitStream::read1Bit(FX_DWORD* dwResult) {
if (!IsInBound())
return -1;
*dwResult = (m_pBuf[m_dwByteIdx] >> (7 - m_dwBitIdx)) & 0x01;
AdvanceBit();
return 0;
}
int32_t CJBig2_BitStream::read1Bit(FX_BOOL* bResult) {
if (!IsInBound())
return -1;
*bResult = (m_pBuf[m_dwByteIdx] >> (7 - m_dwBitIdx)) & 0x01;
AdvanceBit();
return 0;
}
int32_t CJBig2_BitStream::read1Byte(uint8_t* cResult) {
if (!IsInBound())
return -1;
*cResult = m_pBuf[m_dwByteIdx];
++m_dwByteIdx;
return 0;
}
int32_t CJBig2_BitStream::readInteger(FX_DWORD* dwResult) {
if (m_dwByteIdx + 3 >= m_dwLength)
return -1;
*dwResult = (m_pBuf[m_dwByteIdx] << 24) | (m_pBuf[m_dwByteIdx + 1] << 16) |
(m_pBuf[m_dwByteIdx + 2] << 8) | m_pBuf[m_dwByteIdx + 3];
m_dwByteIdx += 4;
return 0;
}
int32_t CJBig2_BitStream::readShortInteger(FX_WORD* dwResult) {
if (m_dwByteIdx + 1 >= m_dwLength)
return -1;
*dwResult = (m_pBuf[m_dwByteIdx] << 8) | m_pBuf[m_dwByteIdx + 1];
m_dwByteIdx += 2;
return 0;
}
void CJBig2_BitStream::alignByte() {
if (m_dwBitIdx != 0) {
++m_dwByteIdx;
m_dwBitIdx = 0;
}
}
uint8_t CJBig2_BitStream::getCurByte() const {
return IsInBound() ? m_pBuf[m_dwByteIdx] : 0;
}
void CJBig2_BitStream::incByteIdx() {
if (IsInBound())
++m_dwByteIdx;
}
uint8_t CJBig2_BitStream::getCurByte_arith() const {
return IsInBound() ? m_pBuf[m_dwByteIdx] : 0xFF;
}
uint8_t CJBig2_BitStream::getNextByte_arith() const {
return m_dwByteIdx + 1 < m_dwLength ? m_pBuf[m_dwByteIdx + 1] : 0xFF;
}
FX_DWORD CJBig2_BitStream::getOffset() const {
return m_dwByteIdx;
}
void CJBig2_BitStream::setOffset(FX_DWORD dwOffset) {
m_dwByteIdx = std::min(dwOffset, m_dwLength);
}
FX_DWORD CJBig2_BitStream::getBitPos() const {
return (m_dwByteIdx << 3) + m_dwBitIdx;
}
void CJBig2_BitStream::setBitPos(FX_DWORD dwBitPos) {
m_dwByteIdx = dwBitPos >> 3;
m_dwBitIdx = dwBitPos & 7;
}
const uint8_t* CJBig2_BitStream::getBuf() const {
return m_pBuf;
}
const uint8_t* CJBig2_BitStream::getPointer() const {
return m_pBuf + m_dwByteIdx;
}
void CJBig2_BitStream::offset(FX_DWORD dwOffset) {
m_dwByteIdx += dwOffset;
}
FX_DWORD CJBig2_BitStream::getByteLeft() const {
return m_dwLength - m_dwByteIdx;
}
void CJBig2_BitStream::AdvanceBit() {
if (m_dwBitIdx == 7) {
++m_dwByteIdx;
m_dwBitIdx = 0;
} else {
++m_dwBitIdx;
}
}
bool CJBig2_BitStream::IsInBound() const {
return m_dwByteIdx < m_dwLength;
}
FX_DWORD CJBig2_BitStream::LengthInBits() const {
return m_dwLength << 3;
}
FX_DWORD CJBig2_BitStream::getObjNum() const {
return m_dwObjNum;
}
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