Disable JBIG2 cache; prevent data corruption

core/src/fxcodec/jbig2/JBig2_Context.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_Context.h"
 
 #include <list>
 
 #include "JBig2_GrdProc.h"
 #include "JBig2_GrrdProc.h"
 #include "JBig2_HtrdProc.h"
 #include "JBig2_PddProc.h"
 #include "JBig2_SddProc.h"
 #include "JBig2_TrdProc.h"
 
 // Implement a very small least recently used (LRU) cache. It is very
 // common for a JBIG2 dictionary to span multiple pages in a PDF file,
 // and we do not want to decode the same dictionary over and over
 // again. We key off of the memory location of the dictionary. The
 // list keeps track of the freshness of entries, with freshest ones
 // at the front. Even a tiny cache size like 2 makes a dramatic
 // difference for typical JBIG2 documents.
-static const int kSymbolDictCacheMaxSize = 2;
+
+// Disable until we can figure out how to clear cache between documents.
+static const int kSymbolDictCacheMaxSize = 0;
 
 CJBig2_Context* CJBig2_Context::CreateContext(
     const uint8_t* pGlobalData,
     FX_DWORD dwGlobalLength,
     const uint8_t* pData,
     FX_DWORD dwLength,
     std::list<CJBig2_CachePair>* pSymbolDictCache,
     IFX_Pause* pPause) {
   return new CJBig2_Context(pGlobalData, dwGlobalLength, pData, dwLength,
                             pSymbolDictCache, pPause);
@@ skipping 1528 matching lines @@
         SBSYMCODES[CURTEMP].code = CURCODE;
         CURCODE = CURCODE + 1;
       }
       CURTEMP = CURTEMP + 1;
     }
     CURLEN = CURLEN + 1;
   }
   FX_Free(LENCOUNT);
   FX_Free(FIRSTCODE);
 }