1ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann// Copyright 2014 PDFium Authors. All rights reserved. 2ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann// Use of this source code is governed by a BSD-style license that can be 3ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann// found in the LICENSE file. 4ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann 5ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann// Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com 6ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann 74d3acf4ec42bf6e838f9060103aff98fbf170794Philip P. Moltmann#include "core/fxcodec/jbig2/JBig2_ArithDecoder.h" 8ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann 94d3acf4ec42bf6e838f9060103aff98fbf170794Philip P. Moltmann#include "core/fxcodec/jbig2/JBig2_BitStream.h" 10d904c1ec7e8d1d86ed56f0dd252435d12cd345aePhilip P. Moltmann#include "core/fxcrt/fx_memory.h" 11ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann 12ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmannnamespace { 13ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann 14ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmannstruct JBig2ArithQe { 15ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann unsigned int Qe; 16ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann unsigned int NMPS; 17ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann unsigned int NLPS; 18ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann unsigned int nSwitch; 19ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann}; 20ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann 21ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmannconst JBig2ArithQe kQeTable[] = { 22ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann // Stupid hack to keep clang-format from reformatting this badly. 234d3acf4ec42bf6e838f9060103aff98fbf170794Philip P. Moltmann {0x5601, 1, 1, 1}, {0x3401, 2, 6, 0}, {0x1801, 3, 9, 0}, 244d3acf4ec42bf6e838f9060103aff98fbf170794Philip P. Moltmann {0x0AC1, 4, 12, 0}, {0x0521, 5, 29, 0}, {0x0221, 38, 33, 0}, 254d3acf4ec42bf6e838f9060103aff98fbf170794Philip P. Moltmann {0x5601, 7, 6, 1}, {0x5401, 8, 14, 0}, {0x4801, 9, 14, 0}, 264d3acf4ec42bf6e838f9060103aff98fbf170794Philip P. Moltmann {0x3801, 10, 14, 0}, {0x3001, 11, 17, 0}, {0x2401, 12, 18, 0}, 274d3acf4ec42bf6e838f9060103aff98fbf170794Philip P. Moltmann {0x1C01, 13, 20, 0}, {0x1601, 29, 21, 0}, {0x5601, 15, 14, 1}, 284d3acf4ec42bf6e838f9060103aff98fbf170794Philip P. Moltmann {0x5401, 16, 14, 0}, {0x5101, 17, 15, 0}, {0x4801, 18, 16, 0}, 294d3acf4ec42bf6e838f9060103aff98fbf170794Philip P. Moltmann {0x3801, 19, 17, 0}, {0x3401, 20, 18, 0}, {0x3001, 21, 19, 0}, 304d3acf4ec42bf6e838f9060103aff98fbf170794Philip P. Moltmann {0x2801, 22, 19, 0}, {0x2401, 23, 20, 0}, {0x2201, 24, 21, 0}, 314d3acf4ec42bf6e838f9060103aff98fbf170794Philip P. Moltmann {0x1C01, 25, 22, 0}, {0x1801, 26, 23, 0}, {0x1601, 27, 24, 0}, 324d3acf4ec42bf6e838f9060103aff98fbf170794Philip P. Moltmann {0x1401, 28, 25, 0}, {0x1201, 29, 26, 0}, {0x1101, 30, 27, 0}, 334d3acf4ec42bf6e838f9060103aff98fbf170794Philip P. Moltmann {0x0AC1, 31, 28, 0}, {0x09C1, 32, 29, 0}, {0x08A1, 33, 30, 0}, 344d3acf4ec42bf6e838f9060103aff98fbf170794Philip P. Moltmann {0x0521, 34, 31, 0}, {0x0441, 35, 32, 0}, {0x02A1, 36, 33, 0}, 354d3acf4ec42bf6e838f9060103aff98fbf170794Philip P. Moltmann {0x0221, 37, 34, 0}, {0x0141, 38, 35, 0}, {0x0111, 39, 36, 0}, 364d3acf4ec42bf6e838f9060103aff98fbf170794Philip P. Moltmann {0x0085, 40, 37, 0}, {0x0049, 41, 38, 0}, {0x0025, 42, 39, 0}, 374d3acf4ec42bf6e838f9060103aff98fbf170794Philip P. Moltmann {0x0015, 43, 40, 0}, {0x0009, 44, 41, 0}, {0x0005, 45, 42, 0}, 384d3acf4ec42bf6e838f9060103aff98fbf170794Philip P. Moltmann {0x0001, 45, 43, 0}, {0x5601, 46, 46, 0}}; 39ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann 40ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmannconst unsigned int kDefaultAValue = 0x8000; 41ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann 42ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmannint DecodeNMPS(JBig2ArithCtx* pCX, const JBig2ArithQe& qe) { 43ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann pCX->I = qe.NMPS; 44ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann return pCX->MPS; 45ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann} 46ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann 47ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmannint DecodeNLPS(JBig2ArithCtx* pCX, const JBig2ArithQe& qe) { 48ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann // TODO(thestig): |D|, |MPS| and friends probably should be booleans. 49ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann int D = 1 - pCX->MPS; 50ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann if (qe.nSwitch == 1) 51ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann pCX->MPS = 1 - pCX->MPS; 52ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann pCX->I = qe.NLPS; 53ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann return D; 54ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann} 55ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann 56ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann} // namespace 57ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann 58ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. MoltmannCJBig2_ArithDecoder::CJBig2_ArithDecoder(CJBig2_BitStream* pStream) 59d904c1ec7e8d1d86ed56f0dd252435d12cd345aePhilip P. Moltmann : m_Complete(false), m_FinishedStream(false), m_pStream(pStream) { 60ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann m_B = m_pStream->getCurByte_arith(); 61ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann m_C = (m_B ^ 0xff) << 16; 62ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann BYTEIN(); 63ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann m_C = m_C << 7; 64ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann m_CT = m_CT - 7; 65ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann m_A = kDefaultAValue; 66ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann} 67ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann 684d3acf4ec42bf6e838f9060103aff98fbf170794Philip P. MoltmannCJBig2_ArithDecoder::~CJBig2_ArithDecoder() {} 69ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann 70ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmannint CJBig2_ArithDecoder::DECODE(JBig2ArithCtx* pCX) { 71ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann if (!pCX || pCX->I >= FX_ArraySize(kQeTable)) 72ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann return 0; 73ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann 74ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann const JBig2ArithQe& qe = kQeTable[pCX->I]; 75ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann m_A -= qe.Qe; 76ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann if ((m_C >> 16) < m_A) { 77ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann if (m_A & kDefaultAValue) 78ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann return pCX->MPS; 79ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann 80ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann const int D = m_A < qe.Qe ? DecodeNLPS(pCX, qe) : DecodeNMPS(pCX, qe); 81ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann ReadValueA(); 82ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann return D; 83ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann } 84ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann 85ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann m_C -= m_A << 16; 86ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann const int D = m_A < qe.Qe ? DecodeNMPS(pCX, qe) : DecodeNLPS(pCX, qe); 87ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann m_A = qe.Qe; 88ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann ReadValueA(); 89ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann return D; 90ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann} 91ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann 92ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmannvoid CJBig2_ArithDecoder::BYTEIN() { 93ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann unsigned char B1; 94ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann if (m_B == 0xff) { 95ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann B1 = m_pStream->getNextByte_arith(); 96ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann if (B1 > 0x8f) { 97ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann m_CT = 8; 98d904c1ec7e8d1d86ed56f0dd252435d12cd345aePhilip P. Moltmann // If we are here, it means that we have finished decoding data (see JBIG2 99d904c1ec7e8d1d86ed56f0dd252435d12cd345aePhilip P. Moltmann // spec, Section E.3.4). If we arrive here a second time, we're looping, 100d904c1ec7e8d1d86ed56f0dd252435d12cd345aePhilip P. Moltmann // so complete decoding. 101d904c1ec7e8d1d86ed56f0dd252435d12cd345aePhilip P. Moltmann if (m_FinishedStream) 102d904c1ec7e8d1d86ed56f0dd252435d12cd345aePhilip P. Moltmann m_Complete = true; 103d904c1ec7e8d1d86ed56f0dd252435d12cd345aePhilip P. Moltmann m_FinishedStream = true; 104ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann } else { 105ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann m_pStream->incByteIdx(); 106ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann m_B = B1; 107ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann m_C = m_C + 0xfe00 - (m_B << 9); 108ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann m_CT = 7; 109ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann } 110ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann } else { 111ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann m_pStream->incByteIdx(); 112ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann m_B = m_pStream->getCurByte_arith(); 113ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann m_C = m_C + 0xff00 - (m_B << 8); 114ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann m_CT = 8; 115ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann } 116d904c1ec7e8d1d86ed56f0dd252435d12cd345aePhilip P. Moltmann 117d904c1ec7e8d1d86ed56f0dd252435d12cd345aePhilip P. Moltmann if (!m_pStream->IsInBounds()) 118d904c1ec7e8d1d86ed56f0dd252435d12cd345aePhilip P. Moltmann m_Complete = true; 119ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann} 120ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann 121ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmannvoid CJBig2_ArithDecoder::ReadValueA() { 122ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann do { 123ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann if (m_CT == 0) 124ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann BYTEIN(); 125ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann m_A <<= 1; 126ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann m_C <<= 1; 127ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann --m_CT; 128ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann } while ((m_A & kDefaultAValue) == 0); 129ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4Philip P. Moltmann} 130