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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"
#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)
return -1;
nVal = (nVal << 1) | nTmp;
++nBits;
for (FX_DWORD 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;
else
*nResult = pTable->RANGELOW[i] + nTmp;
return 0;
}
if (i == pTable->NTEMP - 2)
*nResult = pTable->RANGELOW[i] - nTmp;
else
*nResult = pTable->RANGELOW[i] + nTmp;
return 0;
}
}
}
return -2;
}
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