1// Copyright 2015 PDFium Authors. All rights reserved. 2// Use of this source code is governed by a BSD-style license that can be 3// found in the LICENSE file. 4 5// Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com 6 7#include "core/fxcodec/jbig2/JBig2_BitStream.h" 8 9#include <algorithm> 10 11#include "core/fpdfapi/parser/cpdf_stream.h" 12#include "core/fpdfapi/parser/cpdf_stream_acc.h" 13 14CJBig2_BitStream::CJBig2_BitStream(const RetainPtr<CPDF_StreamAcc>& pSrcStream) 15 : m_pBuf(pSrcStream->GetData()), 16 m_dwLength(pSrcStream->GetSize()), 17 m_dwByteIdx(0), 18 m_dwBitIdx(0), 19 m_dwObjNum(pSrcStream->GetStream() ? pSrcStream->GetStream()->GetObjNum() 20 : 0) { 21 if (m_dwLength > 256 * 1024 * 1024) { 22 m_dwLength = 0; 23 m_pBuf = nullptr; 24 } 25} 26 27CJBig2_BitStream::~CJBig2_BitStream() {} 28 29int32_t CJBig2_BitStream::readNBits(uint32_t dwBits, uint32_t* dwResult) { 30 if (!IsInBounds()) 31 return -1; 32 33 uint32_t dwBitPos = getBitPos(); 34 if (dwBitPos > LengthInBits()) 35 return -1; 36 37 *dwResult = 0; 38 if (dwBitPos + dwBits <= LengthInBits()) 39 dwBitPos = dwBits; 40 else 41 dwBitPos = LengthInBits() - dwBitPos; 42 43 for (; dwBitPos > 0; --dwBitPos) { 44 *dwResult = 45 (*dwResult << 1) | ((m_pBuf[m_dwByteIdx] >> (7 - m_dwBitIdx)) & 0x01); 46 AdvanceBit(); 47 } 48 return 0; 49} 50 51int32_t CJBig2_BitStream::readNBits(uint32_t dwBits, int32_t* nResult) { 52 if (!IsInBounds()) 53 return -1; 54 55 uint32_t dwBitPos = getBitPos(); 56 if (dwBitPos > LengthInBits()) 57 return -1; 58 59 *nResult = 0; 60 if (dwBitPos + dwBits <= LengthInBits()) 61 dwBitPos = dwBits; 62 else 63 dwBitPos = LengthInBits() - dwBitPos; 64 65 for (; dwBitPos > 0; --dwBitPos) { 66 *nResult = 67 (*nResult << 1) | ((m_pBuf[m_dwByteIdx] >> (7 - m_dwBitIdx)) & 0x01); 68 AdvanceBit(); 69 } 70 return 0; 71} 72 73int32_t CJBig2_BitStream::read1Bit(uint32_t* dwResult) { 74 if (!IsInBounds()) 75 return -1; 76 77 *dwResult = (m_pBuf[m_dwByteIdx] >> (7 - m_dwBitIdx)) & 0x01; 78 AdvanceBit(); 79 return 0; 80} 81 82int32_t CJBig2_BitStream::read1Bit(bool* bResult) { 83 if (!IsInBounds()) 84 return -1; 85 86 *bResult = (m_pBuf[m_dwByteIdx] >> (7 - m_dwBitIdx)) & 0x01; 87 AdvanceBit(); 88 return 0; 89} 90 91int32_t CJBig2_BitStream::read1Byte(uint8_t* cResult) { 92 if (!IsInBounds()) 93 return -1; 94 95 *cResult = m_pBuf[m_dwByteIdx]; 96 ++m_dwByteIdx; 97 return 0; 98} 99 100int32_t CJBig2_BitStream::readInteger(uint32_t* dwResult) { 101 if (m_dwByteIdx + 3 >= m_dwLength) 102 return -1; 103 104 *dwResult = (m_pBuf[m_dwByteIdx] << 24) | (m_pBuf[m_dwByteIdx + 1] << 16) | 105 (m_pBuf[m_dwByteIdx + 2] << 8) | m_pBuf[m_dwByteIdx + 3]; 106 m_dwByteIdx += 4; 107 return 0; 108} 109 110int32_t CJBig2_BitStream::readShortInteger(uint16_t* dwResult) { 111 if (m_dwByteIdx + 1 >= m_dwLength) 112 return -1; 113 114 *dwResult = (m_pBuf[m_dwByteIdx] << 8) | m_pBuf[m_dwByteIdx + 1]; 115 m_dwByteIdx += 2; 116 return 0; 117} 118 119void CJBig2_BitStream::alignByte() { 120 if (m_dwBitIdx != 0) { 121 ++m_dwByteIdx; 122 m_dwBitIdx = 0; 123 } 124} 125 126uint8_t CJBig2_BitStream::getCurByte() const { 127 return IsInBounds() ? m_pBuf[m_dwByteIdx] : 0; 128} 129 130void CJBig2_BitStream::incByteIdx() { 131 if (IsInBounds()) 132 ++m_dwByteIdx; 133} 134 135uint8_t CJBig2_BitStream::getCurByte_arith() const { 136 return IsInBounds() ? m_pBuf[m_dwByteIdx] : 0xFF; 137} 138 139uint8_t CJBig2_BitStream::getNextByte_arith() const { 140 return m_dwByteIdx + 1 < m_dwLength ? m_pBuf[m_dwByteIdx + 1] : 0xFF; 141} 142 143uint32_t CJBig2_BitStream::getOffset() const { 144 return m_dwByteIdx; 145} 146 147void CJBig2_BitStream::setOffset(uint32_t dwOffset) { 148 m_dwByteIdx = std::min(dwOffset, m_dwLength); 149} 150 151uint32_t CJBig2_BitStream::getBitPos() const { 152 return (m_dwByteIdx << 3) + m_dwBitIdx; 153} 154 155void CJBig2_BitStream::setBitPos(uint32_t dwBitPos) { 156 m_dwByteIdx = dwBitPos >> 3; 157 m_dwBitIdx = dwBitPos & 7; 158} 159 160const uint8_t* CJBig2_BitStream::getBuf() const { 161 return m_pBuf; 162} 163 164const uint8_t* CJBig2_BitStream::getPointer() const { 165 return m_pBuf + m_dwByteIdx; 166} 167 168void CJBig2_BitStream::offset(uint32_t dwOffset) { 169 m_dwByteIdx += dwOffset; 170} 171 172uint32_t CJBig2_BitStream::getByteLeft() const { 173 return m_dwLength - m_dwByteIdx; 174} 175 176void CJBig2_BitStream::AdvanceBit() { 177 if (m_dwBitIdx == 7) { 178 ++m_dwByteIdx; 179 m_dwBitIdx = 0; 180 } else { 181 ++m_dwBitIdx; 182 } 183} 184 185bool CJBig2_BitStream::IsInBounds() const { 186 return m_dwByteIdx < m_dwLength; 187} 188 189uint32_t CJBig2_BitStream::LengthInBits() const { 190 return m_dwLength << 3; 191} 192 193uint32_t CJBig2_BitStream::getObjNum() const { 194 return m_dwObjNum; 195} 196