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// 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;
}
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