| // 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" |
| |
| #include "JBig2_Define.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 = 0; |
| int nBits = 0; |
| while (1) { |
| FX_DWORD nTmp; |
| if (m_pStream->read1Bit(&nTmp) == -1) |
| break; |
| |
| nVal = (nVal << 1) | nTmp; |
| ++nBits; |
| for (FX_DWORD i = 0; i < pTable->Size(); ++i) { |
| if (pTable->GetPREFLEN()[i] == nBits && pTable->GetCODES()[i] == nVal) { |
| if (pTable->IsHTOOB() && i == pTable->Size() - 1) |
| return JBIG2_OOB; |
| |
| if (m_pStream->readNBits(pTable->GetRANGELEN()[i], &nTmp) == -1) |
| return -1; |
| |
| FX_DWORD offset = pTable->IsHTOOB() ? 3 : 2; |
| if (i == pTable->Size() - offset) |
| *nResult = pTable->GetRANGELOW()[i] - nTmp; |
| else |
| *nResult = pTable->GetRANGELOW()[i] + nTmp; |
| return 0; |
| } |
| } |
| } |
| return -1; |
| } |
