#92806 need to support GB18030 in universal detector

r= ftang sr=blizzard@mozilla.org

This fix also added some comment for:
#33337 Universal Charset Autodetection for mozilla tree
The code is almost the same as in commercial tree, 3rd party detector is removed, and name has been changed by roy.

r=shanjian/ftang  sr=blizzard

extensions/universalchardet/src/base/nsCodingStateMachine.h

@@ -32,6 +32,7 @@ typedef enum {
 
 #define GETCLASS(c) GETFROMPCK(((unsigned char)(c)), mModel->classTable)
 
+//state machine model
 typedef struct 
 {
   nsPkgInt classTable;
@@ -48,12 +49,14 @@ public:
           mModel = sm;
         };
   nsSMState NextState(char c){
+    //for each byte we get its class , if it is first byte, we also get byte length
     PRUint32 byteCls = GETCLASS(c);
     if (mCurrentState == eStart)
     { 
       mCurrentBytePos = 0; 
       mCurrentCharLen = mModel->charLenTable[byteCls];
     }
+    //from byte's class and stateTable, we get its next state
     mCurrentState=(nsSMState)GETFROMPCK(mCurrentState*(mModel->classFactor)+byteCls,
                                        mModel->stateTable);
     mCurrentBytePos++;
@@ -76,7 +79,7 @@ extern SMModel Big5SMModel;
 extern SMModel EUCJPSMModel;
 extern SMModel EUCKRSMModel;
 extern SMModel EUCTWSMModel;
-extern SMModel GB2312SMModel;
+extern SMModel GB18030SMModel;
 extern SMModel SJISSMModel;
 extern SMModel UCS2BESMModel;
 

extensions/universalchardet/src/base/nsGB2312Prober.h

@@ -29,7 +29,7 @@
 
 class nsGB2312Prober: public nsCharSetProber {
 public:
-  nsGB2312Prober(void){mCodingSM = new nsCodingStateMachine(&GB2312SMModel);
+  nsGB2312Prober(void){mCodingSM = new nsCodingStateMachine(&GB18030SMModel);
                       Reset();};
   virtual ~nsGB2312Prober(void){delete mCodingSM;};
   nsProbingState HandleData(const char* aBuf, PRUint32 aLen);

extensions/universalchardet/src/base/nsMBCSSM.cpp

@@ -245,6 +245,7 @@ SMModel EUCTWSMModel = {
   "x-euc-tw",
 };
 
+/* obsolete GB2312 by gb18030
 static PRUint32 GB2312_cls [ 256 / 8 ] = {
 //PCK4BITS(0,1,1,1,1,1,1,1),  // 00 - 07 
 PCK4BITS(1,1,1,1,1,1,1,1),  // 00 - 07 
@@ -296,7 +297,59 @@ SMModel GB2312SMModel = {
   GB2312CharLenTable,
   "GB2312",
 };
+*/
 
+static PRUint32 GB18030_cls [ 256 / 8 ] = {
+//PCK4BITS(0,1,1,1,1,1,1,1),  // 00 - 07 
+PCK4BITS(1,1,1,1,1,1,1,1),  // 00 - 07 
+PCK4BITS(1,1,1,1,1,1,0,0),  // 08 - 0f 
+PCK4BITS(1,1,1,1,1,1,1,1),  // 10 - 17 
+PCK4BITS(1,1,1,0,1,1,1,1),  // 18 - 1f 
+PCK4BITS(1,1,1,1,1,1,1,1),  // 20 - 27 
+PCK4BITS(1,1,1,1,1,1,1,1),  // 28 - 2f 
+PCK4BITS(1,1,1,1,1,1,1,1),  // 30 - 37 
+PCK4BITS(1,1,1,1,1,1,1,1),  // 38 - 3f 
+PCK4BITS(3,3,3,3,3,3,3,3),  // 40 - 47 
+PCK4BITS(3,3,3,3,3,3,3,3),  // 48 - 4f 
+PCK4BITS(3,3,3,3,3,3,3,3),  // 50 - 57 
+PCK4BITS(3,3,3,3,3,3,3,3),  // 58 - 5f 
+PCK4BITS(3,3,3,3,3,3,3,3),  // 60 - 67 
+PCK4BITS(3,3,3,3,3,3,3,3),  // 68 - 6f 
+PCK4BITS(3,3,3,3,3,3,3,3),  // 70 - 77 
+PCK4BITS(3,3,3,3,3,3,3,1),  // 78 - 7f 
+PCK4BITS(3,2,2,2,2,2,2,2),  // 80 - 87 
+PCK4BITS(2,2,2,2,2,2,2,2),  // 88 - 8f 
+PCK4BITS(2,2,2,2,2,2,2,2),  // 90 - 97 
+PCK4BITS(2,2,2,2,2,2,2,2),  // 98 - 9f 
+PCK4BITS(2,2,2,2,2,2,2,2),  // a0 - a7 
+PCK4BITS(2,2,2,2,2,2,2,2),  // a8 - af 
+PCK4BITS(2,2,2,2,2,2,2,2),  // b0 - b7 
+PCK4BITS(2,2,2,2,2,2,2,2),  // b8 - bf 
+PCK4BITS(2,2,2,2,2,2,2,2),  // c0 - c7 
+PCK4BITS(2,2,2,2,2,2,2,2),  // c8 - cf 
+PCK4BITS(2,2,2,2,2,2,2,2),  // d0 - d7 
+PCK4BITS(2,2,2,2,2,2,2,2),  // d8 - df 
+PCK4BITS(2,2,2,2,2,2,2,2),  // e0 - e7 
+PCK4BITS(2,2,2,2,2,2,2,2),  // e8 - ef 
+PCK4BITS(2,2,2,2,2,2,2,2),  // f0 - f7 
+PCK4BITS(2,2,2,2,2,2,2,0)   // f8 - ff 
+};
+
+
+static PRUint32 GB18030_st [ 2] = {
+PCK4BITS(eError,eStart,     3,eStart,eError,eError,eError,eError),//00-07 
+PCK4BITS(eItsMe,eItsMe,eItsMe,eItsMe,eError,eError,eStart,eStart) //08-0f 
+};
+
+static PRUint32 GB18030CharLenTable[] = {0, 1, 2, 0};
+
+SMModel GB18030SMModel = {
+  {eIdxSft4bits, eSftMsk4bits, eBitSft4bits, eUnitMsk4bits, GB18030_cls },
+   4,
+  {eIdxSft4bits, eSftMsk4bits, eBitSft4bits, eUnitMsk4bits, GB18030_st },
+  GB18030CharLenTable,
+  "GB18030",
+};
 
 // sjis