diff --git a/core/fxcodec/jbig2/JBig2_Context.cpp b/core/fxcodec/jbig2/JBig2_Context.cpp
index ef0cb95..ec81990 100644
--- a/core/fxcodec/jbig2/JBig2_Context.cpp
+++ b/core/fxcodec/jbig2/JBig2_Context.cpp
@@ -1240,7 +1240,7 @@
   return SBSYMCODES;
 }
 
-CJBig2_HuffmanTable* CJBig2_Context::GetHuffmanTable(size_t idx) {
+const CJBig2_HuffmanTable* CJBig2_Context::GetHuffmanTable(size_t idx) {
   ASSERT(idx > 0);
   ASSERT(idx < CJBig2_HuffmanTable::kNumHuffmanTables);
   if (!m_HuffmanTables[idx].get())
diff --git a/core/fxcodec/jbig2/JBig2_Context.h b/core/fxcodec/jbig2/JBig2_Context.h
index 3113cce..20828a2 100644
--- a/core/fxcodec/jbig2/JBig2_Context.h
+++ b/core/fxcodec/jbig2/JBig2_Context.h
@@ -79,7 +79,7 @@
 
   std::vector<JBig2HuffmanCode> DecodeSymbolIDHuffmanTable(uint32_t SBNUMSYMS);
 
-  CJBig2_HuffmanTable* GetHuffmanTable(size_t idx);
+  const CJBig2_HuffmanTable* GetHuffmanTable(size_t idx);
 
   std::unique_ptr<CJBig2_Context> m_pGlobalContext;
   std::unique_ptr<CJBig2_BitStream> m_pStream;
diff --git a/core/fxcodec/jbig2/JBig2_HuffmanDecoder.cpp b/core/fxcodec/jbig2/JBig2_HuffmanDecoder.cpp
index 7f250a5..bea2b09 100644
--- a/core/fxcodec/jbig2/JBig2_HuffmanDecoder.cpp
+++ b/core/fxcodec/jbig2/JBig2_HuffmanDecoder.cpp
@@ -14,7 +14,7 @@
 
 CJBig2_HuffmanDecoder::~CJBig2_HuffmanDecoder() {}
 
-int CJBig2_HuffmanDecoder::DecodeAValue(CJBig2_HuffmanTable* pTable,
+int CJBig2_HuffmanDecoder::DecodeAValue(const CJBig2_HuffmanTable* pTable,
                                         int* nResult) {
   FX_SAFE_INT32 nSafeVal = 0;
   int nBits = 0;
diff --git a/core/fxcodec/jbig2/JBig2_HuffmanDecoder.h b/core/fxcodec/jbig2/JBig2_HuffmanDecoder.h
index 5daf1fc..48f8d0f 100644
--- a/core/fxcodec/jbig2/JBig2_HuffmanDecoder.h
+++ b/core/fxcodec/jbig2/JBig2_HuffmanDecoder.h
@@ -16,7 +16,7 @@
   explicit CJBig2_HuffmanDecoder(CJBig2_BitStream* pStream);
   ~CJBig2_HuffmanDecoder();
 
-  int DecodeAValue(CJBig2_HuffmanTable* pTable, int* nResult);
+  int DecodeAValue(const CJBig2_HuffmanTable* pTable, int* nResult);
 
  private:
   UnownedPtr<CJBig2_BitStream> const m_pStream;
diff --git a/core/fxcodec/jbig2/JBig2_SddProc.h b/core/fxcodec/jbig2/JBig2_SddProc.h
index 672c2c3..a6fb039 100644
--- a/core/fxcodec/jbig2/JBig2_SddProc.h
+++ b/core/fxcodec/jbig2/JBig2_SddProc.h
@@ -36,10 +36,10 @@
   CJBig2_Image** SDINSYMS;
   uint32_t SDNUMNEWSYMS;
   uint32_t SDNUMEXSYMS;
-  CJBig2_HuffmanTable* SDHUFFDH;
-  CJBig2_HuffmanTable* SDHUFFDW;
-  CJBig2_HuffmanTable* SDHUFFBMSIZE;
-  CJBig2_HuffmanTable* SDHUFFAGGINST;
+  const CJBig2_HuffmanTable* SDHUFFDH;
+  const CJBig2_HuffmanTable* SDHUFFDW;
+  const CJBig2_HuffmanTable* SDHUFFBMSIZE;
+  const CJBig2_HuffmanTable* SDHUFFAGGINST;
   uint8_t SDTEMPLATE;
   int8_t SDAT[8];
   bool SDRTEMPLATE;
diff --git a/core/fxcodec/jbig2/JBig2_TrdProc.h b/core/fxcodec/jbig2/JBig2_TrdProc.h
index 3db3121..1d90bf4 100644
--- a/core/fxcodec/jbig2/JBig2_TrdProc.h
+++ b/core/fxcodec/jbig2/JBig2_TrdProc.h
@@ -72,14 +72,14 @@
 
   JBig2Corner REFCORNER;
   int8_t SBDSOFFSET;
-  CJBig2_HuffmanTable* SBHUFFFS;
-  CJBig2_HuffmanTable* SBHUFFDS;
-  CJBig2_HuffmanTable* SBHUFFDT;
-  CJBig2_HuffmanTable* SBHUFFRDW;
-  CJBig2_HuffmanTable* SBHUFFRDH;
-  CJBig2_HuffmanTable* SBHUFFRDX;
-  CJBig2_HuffmanTable* SBHUFFRDY;
-  CJBig2_HuffmanTable* SBHUFFRSIZE;
+  const CJBig2_HuffmanTable* SBHUFFFS;
+  const CJBig2_HuffmanTable* SBHUFFDS;
+  const CJBig2_HuffmanTable* SBHUFFDT;
+  const CJBig2_HuffmanTable* SBHUFFRDW;
+  const CJBig2_HuffmanTable* SBHUFFRDH;
+  const CJBig2_HuffmanTable* SBHUFFRDX;
+  const CJBig2_HuffmanTable* SBHUFFRDY;
+  const CJBig2_HuffmanTable* SBHUFFRSIZE;
   bool SBRTEMPLATE;
   int8_t SBRAT[4];