| // 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 i; | |
| int nVal = 0; | |
| int nBits = 0; | |
| FX_DWORD nTmp; | |
| 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; | |
| } |