Fix a heap overflow in CJBig2_Context::parseSymbolDict

core/src/fxcodec/jbig2/JBig2_GeneralDecoder.cpp

 // 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_GeneralDecoder.h"
 #include "JBig2_ArithDecoder.h"
 #include "JBig2_ArithIntDecoder.h"
 #include "JBig2_HuffmanDecoder.h"
@@ skipping 43 matching lines @@
     { 0x0085, 40, 37, 0 },
     { 0x0049, 41, 38, 0 },
     { 0x0025, 42, 39, 0 },
     { 0x0015, 43, 40, 0 },
     { 0x0009, 44, 41, 0 },
     { 0x0005, 45, 42, 0 },
     { 0x0001, 45, 43, 0 },
     { 0x5601, 46, 46, 0 }
 };
 
+extern const unsigned int JBIG2_QE_NUM = sizeof(QeTable) / sizeof(JBig2ArithQe);
+
 CJBig2_Image *CJBig2_GRDProc::decode_Arith(CJBig2_ArithDecoder *pArithDecoder, JBig2ArithCtx *gbContext)
 {
     if (GBW == 0 || GBH == 0) {
         CJBig2_Image* pImage;
         JBIG2_ALLOC(pImage, CJBig2_Image(GBW, GBH));
         return pImage;
     }
     if(GBTEMPLATE == 0) {
         if((GBAT[0] == 3) && (GBAT[1] == (signed char) - 1)
                 && (GBAT[2] == (signed char) - 3) && (GBAT[3] == (signed char) - 1)
@@ skipping 4258 matching lines @@
         }
         if(pPause && pPause->NeedToPauseNow()) {
             m_loopIndex++;
             m_ProssiveStatus = FXCODEC_STATUS_DECODE_TOBECONTINUE;
             return FXCODEC_STATUS_DECODE_TOBECONTINUE;
         }
     }
     m_ProssiveStatus = FXCODEC_STATUS_DECODE_FINISH;
     return FXCODEC_STATUS_DECODE_FINISH;
 }