diff --git a/extensions/universalchardet/src/base/Big5Freq.tab b/extensions/universalchardet/src/base/Big5Freq.tab
index 3d8448624a3..fbd3c224955 100644
--- a/extensions/universalchardet/src/base/Big5Freq.tab
+++ b/extensions/universalchardet/src/base/Big5Freq.tab
@@ -59,7 +59,7 @@
 //Char to FreqOrder table , 
 #define BIG5_TABLE_SIZE  5376
 
-static PRInt16 Big5CharToFreqOrder[] =
+static const PRInt16 Big5CharToFreqOrder[] =
 {
    1,1801,1506, 255,1431, 198,   9,  82,   6,5008, 177, 202,3681,1256,2821, 110, //   16
 3814,  33,3274, 261,  76,  44,2114,  16,2946,2187,1176, 659,3971,  26,3451,2653, //   32
diff --git a/extensions/universalchardet/src/base/CharDistribution.h b/extensions/universalchardet/src/base/CharDistribution.h
index a62471c5942..aa54f0cbee7 100644
--- a/extensions/universalchardet/src/base/CharDistribution.h
+++ b/extensions/universalchardet/src/base/CharDistribution.h
@@ -106,7 +106,7 @@ protected:
   PRUint32 mTotalChars;
 
   //Mapping table to get frequency order from char order (get from GetOrder())
-  PRInt16  *mCharToFreqOrder;
+  const PRInt16  *mCharToFreqOrder;
 
   //Size of above table
   PRUint32 mTableSize;
diff --git a/extensions/universalchardet/src/base/EUCKRFreq.tab b/extensions/universalchardet/src/base/EUCKRFreq.tab
index 0102b162856..93be3313e29 100644
--- a/extensions/universalchardet/src/base/EUCKRFreq.tab
+++ b/extensions/universalchardet/src/base/EUCKRFreq.tab
@@ -56,7 +56,7 @@
 #define EUCKR_TABLE_SIZE  2352
 
 //Char to FreqOrder table , 
-static PRInt16 EUCKRCharToFreqOrder[] =
+static const PRInt16 EUCKRCharToFreqOrder[] =
 {
   13, 130, 120,1396, 481,1719,1720, 328, 609, 212,1721, 707, 400, 299,1722,  87,
 1397,1723, 104, 536,1117,1203,1724,1267, 685,1268, 508,1725,1726,1727,1728,1398,
diff --git a/extensions/universalchardet/src/base/EUCTWFreq.tab b/extensions/universalchardet/src/base/EUCTWFreq.tab
index 92349675be0..c45ef035497 100644
--- a/extensions/universalchardet/src/base/EUCTWFreq.tab
+++ b/extensions/universalchardet/src/base/EUCTWFreq.tab
@@ -60,7 +60,7 @@
 //Char to FreqOrder table , 
 #define EUCTW_TABLE_SIZE  8102
 
-static PRInt16 EUCTWCharToFreqOrder[] =
+static const PRInt16 EUCTWCharToFreqOrder[] =
 {
    1,1800,1506, 255,1431, 198,   9,  82,   6,7310, 177, 202,3615,1256,2808, 110, // 2742
 3735,  33,3241, 261,  76,  44,2113,  16,2931,2184,1176, 659,3868,  26,3404,2643, // 2758
diff --git a/extensions/universalchardet/src/base/GB2312Freq.tab b/extensions/universalchardet/src/base/GB2312Freq.tab
index 9180ffcd0cd..e7cb4cabbc2 100644
--- a/extensions/universalchardet/src/base/GB2312Freq.tab
+++ b/extensions/universalchardet/src/base/GB2312Freq.tab
@@ -56,7 +56,7 @@
 
 #define GB2312_TABLE_SIZE  3760
 
-static PRInt16 GB2312CharToFreqOrder[] =
+static const PRInt16 GB2312CharToFreqOrder[] =
 {
 1671, 749,1443,2364,3924,3807,2330,3921,1704,3463,2691,1511,1515, 572,3191,2205,
 2361, 224,2558, 479,1711, 963,3162, 440,4060,1905,2966,2947,3580,2647,3961,3842,
diff --git a/extensions/universalchardet/src/base/JISFreq.tab b/extensions/universalchardet/src/base/JISFreq.tab
index d7b78643221..6b47c103afa 100644
--- a/extensions/universalchardet/src/base/JISFreq.tab
+++ b/extensions/universalchardet/src/base/JISFreq.tab
@@ -60,7 +60,7 @@
 //Char to FreqOrder table , 
 #define JIS_TABLE_SIZE  4368
 
-static PRInt16 JISCharToFreqOrder[] =
+static const PRInt16 JISCharToFreqOrder[] =
 {
   40,   1,   6, 182, 152, 180, 295,2127, 285, 381,3295,4304,3068,4606,3165,3510, //   16
 3511,1822,2785,4607,1193,2226,5070,4608, 171,2996,1247,  18, 179,5071, 856,1661, //   32
diff --git a/extensions/universalchardet/src/base/nsCodingStateMachine.h b/extensions/universalchardet/src/base/nsCodingStateMachine.h
index 9f4f4b4231a..b9c3ee7adb3 100644
--- a/extensions/universalchardet/src/base/nsCodingStateMachine.h
+++ b/extensions/universalchardet/src/base/nsCodingStateMachine.h
@@ -54,7 +54,7 @@ typedef struct
   nsPkgInt classTable;
   PRUint32 classFactor;
   nsPkgInt stateTable;
-  PRUint32* charLenTable;
+  const PRUint32* charLenTable;
   const char* name;
 } SMModel;
 
diff --git a/extensions/universalchardet/src/base/nsEscSM.cpp b/extensions/universalchardet/src/base/nsEscSM.cpp
index ab9fc4132ba..349c862227b 100644
--- a/extensions/universalchardet/src/base/nsEscSM.cpp
+++ b/extensions/universalchardet/src/base/nsEscSM.cpp
@@ -82,7 +82,7 @@ PCK4BITS(     4,eError,     4,     4,     4,eError,     4,eError),//20-27
 PCK4BITS(     4,eItsMe,eStart,eStart,eStart,eStart,eStart,eStart) //28-2f 
 };
 
-static PRUint32 HZCharLenTable[] = {0, 0, 0, 0, 0, 0};
+static const PRUint32 HZCharLenTable[] = {0, 0, 0, 0, 0, 0};
 
 SMModel HZSMModel = {
   {eIdxSft4bits, eSftMsk4bits, eBitSft4bits, eUnitMsk4bits, HZ_cls },
@@ -140,7 +140,7 @@ PCK4BITS(eError,eError,eError,eItsMe,eError,eError,eError,eError),//30-37
 PCK4BITS(eError,eError,eError,eError,eError,eItsMe,eError,eStart) //38-3f 
 };
 
-static PRUint32 ISO2022CNCharLenTable[] = {0, 0, 0, 0, 0, 0, 0, 0, 0};
+static const PRUint32 ISO2022CNCharLenTable[] = {0, 0, 0, 0, 0, 0, 0, 0, 0};
 
 SMModel ISO2022CNSMModel = {
   {eIdxSft4bits, eSftMsk4bits, eBitSft4bits, eUnitMsk4bits, ISO2022CN_cls },
@@ -195,7 +195,7 @@ PCK4BITS(eError,eError,eError,eError,eItsMe,eError,eItsMe,eError),//20-27
 PCK4BITS(eError,eError,eError,eError,eItsMe,eItsMe,eError,eError) //28-2f 
 };
 
-static PRUint32 ISO2022JPCharLenTable[] = {0, 0, 0, 0, 0, 0, 0, 0};
+static const PRUint32 ISO2022JPCharLenTable[] = {0, 0, 0, 0, 0, 0, 0, 0};
 
 SMModel ISO2022JPSMModel = {
   {eIdxSft4bits, eSftMsk4bits, eBitSft4bits, eUnitMsk4bits, ISO2022JP_cls },
@@ -249,7 +249,7 @@ PCK4BITS(eError,eError,eError,eError,     5,eError,eError,eError),//18-1f
 PCK4BITS(eError,eError,eError,eItsMe,eStart,eStart,eStart,eStart) //20-27 
 };
 
-static PRUint32 ISO2022KRCharLenTable[] = {0, 0, 0, 0, 0, 0};
+static const PRUint32 ISO2022KRCharLenTable[] = {0, 0, 0, 0, 0, 0};
 
 SMModel ISO2022KRSMModel = {
   {eIdxSft4bits, eSftMsk4bits, eBitSft4bits, eUnitMsk4bits, ISO2022KR_cls },
diff --git a/extensions/universalchardet/src/base/nsMBCSSM.cpp b/extensions/universalchardet/src/base/nsMBCSSM.cpp
index b531bdda5bc..94c6c4ff536 100644
--- a/extensions/universalchardet/src/base/nsMBCSSM.cpp
+++ b/extensions/universalchardet/src/base/nsMBCSSM.cpp
@@ -88,7 +88,7 @@ PCK4BITS(eError,eError,eItsMe,eItsMe,eItsMe,eItsMe,eItsMe,eError),//08-0f
 PCK4BITS(eError,eStart,eStart,eStart,eStart,eStart,eStart,eStart) //10-17 
 };
 
-static PRUint32 Big5CharLenTable[] = {0, 1, 1, 2, 0};
+static const PRUint32 Big5CharLenTable[] = {0, 1, 1, 2, 0};
 
 SMModel Big5SMModel = {
   {eIdxSft4bits, eSftMsk4bits, eBitSft4bits, eUnitMsk4bits, BIG5_cls },
@@ -143,7 +143,7 @@ PCK4BITS(eError,eError,eStart,eError,eError,eError,     3,eError),//18-1f
 PCK4BITS(     3,eError,eError,eError,eStart,eStart,eStart,eStart) //20-27 
 };
 
-static PRUint32 EUCJPCharLenTable[] = {2, 2, 2, 3, 1, 0};
+static const PRUint32 EUCJPCharLenTable[] = {2, 2, 2, 3, 1, 0};
 
 SMModel EUCJPSMModel = {
   {eIdxSft4bits, eSftMsk4bits, eBitSft4bits, eUnitMsk4bits, EUCJP_cls },
@@ -195,7 +195,7 @@ PCK4BITS(eError,eStart,     3,eError,eError,eError,eError,eError),//00-07
 PCK4BITS(eItsMe,eItsMe,eItsMe,eItsMe,eError,eError,eStart,eStart) //08-0f 
 };
 
-static PRUint32 EUCKRCharLenTable[] = {0, 1, 2, 0};
+static const PRUint32 EUCKRCharLenTable[] = {0, 1, 2, 0};
 
 SMModel EUCKRSMModel = {
   {eIdxSft4bits, eSftMsk4bits, eBitSft4bits, eUnitMsk4bits, EUCKR_cls },
@@ -251,7 +251,7 @@ PCK4BITS(     5,eError,eError,eError,eStart,eError,eStart,eStart),//20-27
 PCK4BITS(eStart,eError,eStart,eStart,eStart,eStart,eStart,eStart) //28-2f 
 };
 
-static PRUint32 EUCTWCharLenTable[] = {0, 0, 1, 2, 2, 2, 3};
+static const PRUint32 EUCTWCharLenTable[] = {0, 0, 1, 2, 2, 2, 3};
 
 SMModel EUCTWSMModel = {
   {eIdxSft4bits, eSftMsk4bits, eBitSft4bits, eUnitMsk4bits, EUCTW_cls },
@@ -304,7 +304,7 @@ PCK4BITS(eError,eStart,     3,eError,eError,eError,eError,eError),//00-07
 PCK4BITS(eItsMe,eItsMe,eItsMe,eItsMe,eError,eError,eStart,eStart) //08-0f 
 };
 
-static PRUint32 GB2312CharLenTable[] = {0, 1, 2, 0};
+static const PRUint32 GB2312CharLenTable[] = {0, 1, 2, 0};
 
 SMModel GB2312SMModel = {
   {eIdxSft4bits, eSftMsk4bits, eBitSft4bits, eUnitMsk4bits, GB2312_cls },
@@ -367,7 +367,7 @@ PCK4BITS(eError,eError,eStart,eStart,eStart,eStart,eStart,eStart) //28-2f
 // it is used for frequency analysis only, and we are validing 
 // each code range there as well. So it is safe to set it to be 
 // 2 here. 
-static PRUint32 GB18030CharLenTable[] = {0, 1, 1, 1, 1, 1, 2};
+static const PRUint32 GB18030CharLenTable[] = {0, 1, 1, 1, 1, 1, 2};
 
 SMModel GB18030SMModel = {
   {eIdxSft4bits, eSftMsk4bits, eBitSft4bits, eUnitMsk4bits, GB18030_cls },
@@ -424,7 +424,7 @@ PCK4BITS(eError,eError,eError,eError,eItsMe,eItsMe,eItsMe,eItsMe),//08-0f
 PCK4BITS(eItsMe,eItsMe,eError,eError,eStart,eStart,eStart,eStart) //10-17 
 };
 
-static PRUint32 SJISCharLenTable[] = {0, 1, 1, 2, 0, 0};
+static const PRUint32 SJISCharLenTable[] = {0, 1, 1, 2, 0, 0};
 
 SMModel SJISSMModel = {
   {eIdxSft4bits, eSftMsk4bits, eBitSft4bits, eUnitMsk4bits, SJIS_cls },
@@ -481,7 +481,7 @@ PCK4BITS(     5,     8,     6,     6,eError,     6,     6,     6),//28-2f
 PCK4BITS(     6,     6,     6,     6,eError,eError,eStart,eStart) //30-37 
 };
 
-static PRUint32 UCS2BECharLenTable[] = {2, 2, 2, 0, 2, 2};
+static const PRUint32 UCS2BECharLenTable[] = {2, 2, 2, 0, 2, 2};
 
 SMModel UCS2BESMModel = {
   {eIdxSft4bits, eSftMsk4bits, eBitSft4bits, eUnitMsk4bits, UCS2BE_cls },
@@ -537,7 +537,7 @@ PCK4BITS(     5,     5,     5,eError,eError,eError,     5,     5),//28-2f
 PCK4BITS(     5,     5,     5,eError,     5,eError,eStart,eStart) //30-37 
 };
 
-static PRUint32 UCS2LECharLenTable[] = {2, 2, 2, 2, 2, 2};
+static const PRUint32 UCS2LECharLenTable[] = {2, 2, 2, 2, 2, 2};
 
 SMModel UCS2LESMModel = {
   {eIdxSft4bits, eSftMsk4bits, eBitSft4bits, eUnitMsk4bits, UCS2LE_cls },
@@ -614,7 +614,7 @@ PCK4BITS(eError,eError,eStart,eStart,eStart,eStart,eError,eError),//c0-c7
 PCK4BITS(eError,eError,eError,eError,eError,eError,eError,eError) //c8-cf 
 };
 
-static PRUint32 UTF8CharLenTable[] = {0, 1, 0, 0, 0, 0, 2, 3, 
+static const PRUint32 UTF8CharLenTable[] = {0, 1, 0, 0, 0, 0, 2, 3, 
                             3, 3, 4, 4, 5, 5, 6, 6 };
 
 SMModel UTF8SMModel = {