| // Copyright 2014 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_HuffmanDecoder.h" | |
| CJBig2_HuffmanDecoder::CJBig2_HuffmanDecoder(CJBig2_BitStream *pStream) | |
| { | |
| m_pStream = pStream; | |
| } | |
| CJBig2_HuffmanDecoder::~CJBig2_HuffmanDecoder() | |
| { | |
| } | |
| int CJBig2_HuffmanDecoder::decodeAValue(CJBig2_HuffmanTable *pTable, int *nResult) | |
| { | |
| int nVal, nTmp, i, nBits; | |
| nVal = 0; | |
| nBits = 0; | |
| while(1) { | |
| if(m_pStream->read1Bit(&nTmp) == -1) { | |
| return -1; | |
| } | |
| nVal = (nVal << 1) | nTmp; | |
| nBits ++; | |
| for(i = 0; i < pTable->NTEMP; i++) { | |
| if((pTable->PREFLEN[i] == nBits) && (pTable->CODES[i] == nVal)) { | |
| if((pTable->HTOOB == 1) && (i == pTable->NTEMP - 1)) { | |
| return JBIG2_OOB; | |
| } | |
| if(m_pStream->readNBits(pTable->RANGELEN[i], &nTmp) == -1) { | |
| return -1; | |
| } | |
| if(pTable->HTOOB) { | |
| if(i == pTable->NTEMP - 3) { | |
| *nResult = pTable->RANGELOW[i] - nTmp; | |
| return 0; | |
| } else { | |
| *nResult = pTable->RANGELOW[i] + nTmp; | |
| return 0; | |
| } | |
| } else { | |
| if(i == pTable->NTEMP - 2) { | |
| *nResult = pTable->RANGELOW[i] - nTmp; | |
| return 0; | |
| } else { | |
| *nResult = pTable->RANGELOW[i] + nTmp; | |
| return 0; | |
| } | |
| } | |
| } | |
| } | |
| } | |
| return -2; | |
| } |