src/cobalt/debug/remote/devtools/node_modules/chardet/encoding/mbcs.js - cobalt - Git at Google

 var util = require('util'),
   Match = require ('../match');

 /**
  * Binary search implementation (recursive)
  */
 function binarySearch(arr, searchValue) {
   function find(arr, searchValue, left, right) {
     if (right < left)
       return -1;

     /*
     int mid = mid = (left + right) / 2;
     There is a bug in the above line;
     Joshua Bloch suggests the following replacement:
     */
     var mid = Math.floor((left + right) >>> 1);
     if (searchValue > arr[mid])
       return find(arr, searchValue, mid + 1, right);

     if (searchValue < arr[mid])
       return find(arr, searchValue, left, mid - 1);

     return mid;
   };

   return find(arr, searchValue, 0, arr.length - 1);
 };

 // 'Character'  iterated character class.
 //    Recognizers for specific mbcs encodings make their 'characters' available
 //    by providing a nextChar() function that fills in an instance of iteratedChar
 //    with the next char from the input.
 //    The returned characters are not converted to Unicode, but remain as the raw
 //    bytes (concatenated into an int) from the codepage data.
 //
 //  For Asian charsets, use the raw input rather than the input that has been
 //   stripped of markup.  Detection only considers multi-byte chars, effectively
 //   stripping markup anyway, and double byte chars do occur in markup too.
 //
 function IteratedChar() {

   this.charValue = 0; // 1-4 bytes from the raw input data
   this.index     = 0;
   this.nextIndex = 0;
   this.error     = false;
   this.done      = false;

   this.reset = function() {
     this.charValue = 0;
     this.index     = -1;
     this.nextIndex = 0;
     this.error     = false;
     this.done      = false;
   };

   this.nextByte = function(det) {
     if (this.nextIndex >= det.fRawLength) {
       this.done = true;
       return -1;
     }
     var byteValue = det.fRawInput[this.nextIndex++] & 0x00ff;
     return byteValue;
   };
 };


 /**
  * Asian double or multi-byte - charsets.
  * Match is determined mostly by the input data adhering to the
  * encoding scheme for the charset, and, optionally,
  * frequency-of-occurence of characters.
  */

 function mbcs() {};

 /**
  * Test the match of this charset with the input text data
  *      which is obtained via the CharsetDetector object.
  *
  * @param det  The CharsetDetector, which contains the input text
  *             to be checked for being in this charset.
  * @return     Two values packed into one int  (Damn java, anyhow)
  *             bits 0-7:  the match confidence, ranging from 0-100
  *             bits 8-15: The match reason, an enum-like value.
  */
 mbcs.prototype.match = function(det) {

   var singleByteCharCount = 0,  //TODO Do we really need this?
     doubleByteCharCount = 0,
     commonCharCount     = 0,
     badCharCount        = 0,
     totalCharCount      = 0,
     confidence          = 0;

   var iter = new IteratedChar();

   detectBlock: {
     for (iter.reset(); this.nextChar(iter, det);) {
       totalCharCount++;
       if (iter.error) {
         badCharCount++;
       } else {
         var cv = iter.charValue & 0xFFFFFFFF;

         if (cv <= 0xff) {
           singleByteCharCount++;
         } else {
           doubleByteCharCount++;
           if (this.commonChars != null) {
             // NOTE: This assumes that there are no 4-byte common chars.
             if (binarySearch(this.commonChars, cv) >= 0) {
               commonCharCount++;
             }
           }
         }
       }
       if (badCharCount >= 2 && badCharCount * 5 >= doubleByteCharCount) {
         // console.log('its here!')
         // Bail out early if the byte data is not matching the encoding scheme.
         break detectBlock;
       }
     }

     if (doubleByteCharCount <= 10 && badCharCount== 0) {
       // Not many multi-byte chars.
       if (doubleByteCharCount == 0 && totalCharCount < 10) {
         // There weren't any multibyte sequences, and there was a low density of non-ASCII single bytes.
         // We don't have enough data to have any confidence.
         // Statistical analysis of single byte non-ASCII charcters would probably help here.
         confidence = 0;
       }
       else {
         //   ASCII or ISO file?  It's probably not our encoding,
         //   but is not incompatible with our encoding, so don't give it a zero.
         confidence = 10;
       }
       break detectBlock;
     }

     //
     //  No match if there are too many characters that don't fit the encoding scheme.
     //    (should we have zero tolerance for these?)
     //
     if (doubleByteCharCount < 20 * badCharCount) {
       confidence = 0;
       break detectBlock;
     }

     if (this.commonChars == null) {
       // We have no statistics on frequently occuring characters.
       //  Assess confidence purely on having a reasonable number of
       //  multi-byte characters (the more the better
       confidence = 30 + doubleByteCharCount - 20 * badCharCount;
       if (confidence > 100) {
         confidence = 100;
       }
     } else {
       //
       // Frequency of occurence statistics exist.
       //
       var maxVal = Math.log(parseFloat(doubleByteCharCount) / 4);
       var scaleFactor = 90.0 / maxVal;
       confidence = Math.floor(Math.log(commonCharCount + 1) * scaleFactor + 10);
       confidence = Math.min(confidence, 100);
     }
   }   // end of detectBlock:

   return confidence == 0 ? null : new Match(det, this, confidence);
 };

 /**
  * Get the next character (however many bytes it is) from the input data
  *    Subclasses for specific charset encodings must implement this function
  *    to get characters according to the rules of their encoding scheme.
  *
  *  This function is not a method of class iteratedChar only because
  *   that would require a lot of extra derived classes, which is awkward.
  * @param it  The iteratedChar 'struct' into which the returned char is placed.
  * @param det The charset detector, which is needed to get at the input byte data
  *            being iterated over.
  * @return    True if a character was returned, false at end of input.
  */

 mbcs.prototype.nextChar = function(iter, det) {};


 /**
  * Shift-JIS charset recognizer.
  */
 module.exports.sjis = function() {
   this.name = function() {
     return 'Shift-JIS';
   };
   this.language = function() {
     return 'ja';
   };

   // TODO:  This set of data comes from the character frequency-
   //        of-occurence analysis tool.  The data needs to be moved
   //        into a resource and loaded from there.
   this.commonChars = [
     0x8140, 0x8141, 0x8142, 0x8145, 0x815b, 0x8169, 0x816a, 0x8175, 0x8176, 0x82a0,
     0x82a2, 0x82a4, 0x82a9, 0x82aa, 0x82ab, 0x82ad, 0x82af, 0x82b1, 0x82b3, 0x82b5,
     0x82b7, 0x82bd, 0x82be, 0x82c1, 0x82c4, 0x82c5, 0x82c6, 0x82c8, 0x82c9, 0x82cc,
     0x82cd, 0x82dc, 0x82e0, 0x82e7, 0x82e8, 0x82e9, 0x82ea, 0x82f0, 0x82f1, 0x8341,
     0x8343, 0x834e, 0x834f, 0x8358, 0x835e, 0x8362, 0x8367, 0x8375, 0x8376, 0x8389,
     0x838a, 0x838b, 0x838d, 0x8393, 0x8e96, 0x93fa, 0x95aa
   ];

   this.nextChar = function(iter, det) {
     iter.index = iter.nextIndex;
     iter.error = false;

     var firstByte;
     firstByte = iter.charValue = iter.nextByte(det);
     if (firstByte < 0)
       return false;

     if (firstByte <= 0x7f || (firstByte > 0xa0 && firstByte <= 0xdf))
       return true;

     var secondByte = iter.nextByte(det);
     if (secondByte < 0)
       return false;

     iter.charValue = (firstByte << 8) | secondByte;
     if (! ((secondByte >= 0x40 && secondByte <= 0x7f) || (secondByte >= 0x80 && secondByte <= 0xff))) {
       // Illegal second byte value.
       iter.error = true;
     }
     return true;
   };
 };
 util.inherits(module.exports.sjis, mbcs);


 /**
  *   Big5 charset recognizer.
  */
 module.exports.big5 = function() {
   this.name = function() {
     return 'Big5';
   };
   this.language = function() {
     return 'zh';
   };
   // TODO:  This set of data comes from the character frequency-
   //        of-occurence analysis tool.  The data needs to be moved
   //        into a resource and loaded from there.
   this.commonChars = [
     0xa140, 0xa141, 0xa142, 0xa143, 0xa147, 0xa149, 0xa175, 0xa176, 0xa440, 0xa446,
     0xa447, 0xa448, 0xa451, 0xa454, 0xa457, 0xa464, 0xa46a, 0xa46c, 0xa477, 0xa4a3,
     0xa4a4, 0xa4a7, 0xa4c1, 0xa4ce, 0xa4d1, 0xa4df, 0xa4e8, 0xa4fd, 0xa540, 0xa548,
     0xa558, 0xa569, 0xa5cd, 0xa5e7, 0xa657, 0xa661, 0xa662, 0xa668, 0xa670, 0xa6a8,
     0xa6b3, 0xa6b9, 0xa6d3, 0xa6db, 0xa6e6, 0xa6f2, 0xa740, 0xa751, 0xa759, 0xa7da,
     0xa8a3, 0xa8a5, 0xa8ad, 0xa8d1, 0xa8d3, 0xa8e4, 0xa8fc, 0xa9c0, 0xa9d2, 0xa9f3,
     0xaa6b, 0xaaba, 0xaabe, 0xaacc, 0xaafc, 0xac47, 0xac4f, 0xacb0, 0xacd2, 0xad59,
     0xaec9, 0xafe0, 0xb0ea, 0xb16f, 0xb2b3, 0xb2c4, 0xb36f, 0xb44c, 0xb44e, 0xb54c,
     0xb5a5, 0xb5bd, 0xb5d0, 0xb5d8, 0xb671, 0xb7ed, 0xb867, 0xb944, 0xbad8, 0xbb44,
     0xbba1, 0xbdd1, 0xc2c4, 0xc3b9, 0xc440, 0xc45f
   ];
   this.nextChar = function(iter, det) {
     iter.index = iter.nextIndex;
     iter.error = false;

     var firstByte = iter.charValue = iter.nextByte(det);

     if (firstByte < 0)
       return false;

     // single byte character.
     if (firstByte <= 0x7f || firstByte == 0xff)
       return true;

     var secondByte = iter.nextByte(det);

     if (secondByte < 0)
       return false;

     iter.charValue = (iter.charValue << 8) | secondByte;

     if (secondByte < 0x40 || secondByte == 0x7f || secondByte == 0xff)
       iter.error = true;

     return true;
   };
 };
 util.inherits(module.exports.big5, mbcs);


 /**
  *  EUC charset recognizers.  One abstract class that provides the common function
  *  for getting the next character according to the EUC encoding scheme,
  *  and nested derived classes for EUC_KR, EUC_JP, EUC_CN.
  *
  *  Get the next character value for EUC based encodings.
  *  Character 'value' is simply the raw bytes that make up the character
  *     packed into an int.
  */
 function eucNextChar(iter, det) {
   iter.index = iter.nextIndex;
   iter.error = false;
   var firstByte  = 0;
   var secondByte = 0;
   var thirdByte  = 0;
   //int fourthByte = 0;
   buildChar: {
     firstByte = iter.charValue = iter.nextByte(det);
     if (firstByte < 0) {
       // Ran off the end of the input data
       iter.done = true;
       break buildChar;
     }
     if (firstByte <= 0x8d) {
       // single byte char
       break buildChar;
     }
     secondByte = iter.nextByte(det);
     iter.charValue = (iter.charValue << 8) | secondByte;
     if (firstByte >= 0xA1 && firstByte <= 0xfe) {
       // Two byte Char
       if (secondByte < 0xa1) {
         iter.error = true;
       }
       break buildChar;
     }
     if (firstByte == 0x8e) {
       // Code Set 2.
       //   In EUC-JP, total char size is 2 bytes, only one byte of actual char value.
       //   In EUC-TW, total char size is 4 bytes, three bytes contribute to char value.
       // We don't know which we've got.
       // Treat it like EUC-JP.  If the data really was EUC-TW, the following two
       //   bytes will look like a well formed 2 byte char.
       if (secondByte < 0xa1) {
         iter.error = true;
       }
       break buildChar;
     }
     if (firstByte == 0x8f) {
       // Code set 3.
       // Three byte total char size, two bytes of actual char value.
       thirdByte = iter.nextByte(det);
       iter.charValue = (iter.charValue << 8) | thirdByte;
       if (thirdByte < 0xa1) {
         iter.error = true;
       }
     }
   }
   return iter.done == false;
 };


 /**
  * The charset recognize for EUC-JP.  A singleton instance of this class
  *    is created and kept by the public CharsetDetector class
  */
 module.exports.euc_jp = function() {
   this.name = function() {
     return 'EUC-JP';
   };
   this.language = function() {
     return 'ja';
   };

   // TODO:  This set of data comes from the character frequency-
   //        of-occurence analysis tool.  The data needs to be moved
   //        into a resource and loaded from there.
   this.commonChars = [
     0xa1a1, 0xa1a2, 0xa1a3, 0xa1a6, 0xa1bc, 0xa1ca, 0xa1cb, 0xa1d6, 0xa1d7, 0xa4a2,
     0xa4a4, 0xa4a6, 0xa4a8, 0xa4aa, 0xa4ab, 0xa4ac, 0xa4ad, 0xa4af, 0xa4b1, 0xa4b3,
     0xa4b5, 0xa4b7, 0xa4b9, 0xa4bb, 0xa4bd, 0xa4bf, 0xa4c0, 0xa4c1, 0xa4c3, 0xa4c4,
     0xa4c6, 0xa4c7, 0xa4c8, 0xa4c9, 0xa4ca, 0xa4cb, 0xa4ce, 0xa4cf, 0xa4d0, 0xa4de,
     0xa4df, 0xa4e1, 0xa4e2, 0xa4e4, 0xa4e8, 0xa4e9, 0xa4ea, 0xa4eb, 0xa4ec, 0xa4ef,
     0xa4f2, 0xa4f3, 0xa5a2, 0xa5a3, 0xa5a4, 0xa5a6, 0xa5a7, 0xa5aa, 0xa5ad, 0xa5af,
     0xa5b0, 0xa5b3, 0xa5b5, 0xa5b7, 0xa5b8, 0xa5b9, 0xa5bf, 0xa5c3, 0xa5c6, 0xa5c7,
     0xa5c8, 0xa5c9, 0xa5cb, 0xa5d0, 0xa5d5, 0xa5d6, 0xa5d7, 0xa5de, 0xa5e0, 0xa5e1,
     0xa5e5, 0xa5e9, 0xa5ea, 0xa5eb, 0xa5ec, 0xa5ed, 0xa5f3, 0xb8a9, 0xb9d4, 0xbaee,
     0xbbc8, 0xbef0, 0xbfb7, 0xc4ea, 0xc6fc, 0xc7bd, 0xcab8, 0xcaf3, 0xcbdc, 0xcdd1
   ];

   this.nextChar = eucNextChar;
 };
 util.inherits(module.exports.euc_jp, mbcs);


 /**
  * The charset recognize for EUC-KR.  A singleton instance of this class
  *    is created and kept by the public CharsetDetector class
  */
 module.exports.euc_kr = function() {
   this.name = function() {
     return 'EUC-KR';
   };
   this.language = function() {
     return 'ko';
   };

   // TODO:  This set of data comes from the character frequency-
   //        of-occurence analysis tool.  The data needs to be moved
   //        into a resource and loaded from there.
   this.commonChars = [
     0xb0a1, 0xb0b3, 0xb0c5, 0xb0cd, 0xb0d4, 0xb0e6, 0xb0ed, 0xb0f8, 0xb0fa, 0xb0fc,
     0xb1b8, 0xb1b9, 0xb1c7, 0xb1d7, 0xb1e2, 0xb3aa, 0xb3bb, 0xb4c2, 0xb4cf, 0xb4d9,
     0xb4eb, 0xb5a5, 0xb5b5, 0xb5bf, 0xb5c7, 0xb5e9, 0xb6f3, 0xb7af, 0xb7c2, 0xb7ce,
     0xb8a6, 0xb8ae, 0xb8b6, 0xb8b8, 0xb8bb, 0xb8e9, 0xb9ab, 0xb9ae, 0xb9cc, 0xb9ce,
     0xb9fd, 0xbab8, 0xbace, 0xbad0, 0xbaf1, 0xbbe7, 0xbbf3, 0xbbfd, 0xbcad, 0xbcba,
     0xbcd2, 0xbcf6, 0xbdba, 0xbdc0, 0xbdc3, 0xbdc5, 0xbec6, 0xbec8, 0xbedf, 0xbeee,
     0xbef8, 0xbefa, 0xbfa1, 0xbfa9, 0xbfc0, 0xbfe4, 0xbfeb, 0xbfec, 0xbff8, 0xc0a7,
     0xc0af, 0xc0b8, 0xc0ba, 0xc0bb, 0xc0bd, 0xc0c7, 0xc0cc, 0xc0ce, 0xc0cf, 0xc0d6,
     0xc0da, 0xc0e5, 0xc0fb, 0xc0fc, 0xc1a4, 0xc1a6, 0xc1b6, 0xc1d6, 0xc1df, 0xc1f6,
     0xc1f8, 0xc4a1, 0xc5cd, 0xc6ae, 0xc7cf, 0xc7d1, 0xc7d2, 0xc7d8, 0xc7e5, 0xc8ad
   ];

   this.nextChar = eucNextChar;
 };
 util.inherits(module.exports.euc_kr, mbcs);


 /**
  *   GB-18030 recognizer. Uses simplified Chinese statistics.
  */
 module.exports.gb_18030 = function() {
   this.name = function() {
     return 'GB18030';
   };
   this.language = function() {
     return 'zh';
   };

   /*
    *  Get the next character value for EUC based encodings.
    *  Character 'value' is simply the raw bytes that make up the character
    *     packed into an int.
    */
   this.nextChar = function(iter, det) {
     iter.index = iter.nextIndex;
     iter.error = false;
     var firstByte  = 0;
     var secondByte = 0;
     var thirdByte  = 0;
     var fourthByte = 0;
     buildChar: {
       firstByte = iter.charValue = iter.nextByte(det);
       if (firstByte < 0) {
         // Ran off the end of the input data
         iter.done = true;
         break buildChar;
       }
       if (firstByte <= 0x80) {
         // single byte char
         break buildChar;
       }
       secondByte = iter.nextByte(det);
       iter.charValue = (iter.charValue << 8) | secondByte;
       if (firstByte >= 0x81 && firstByte <= 0xFE) {
         // Two byte Char
         if ((secondByte >= 0x40 && secondByte <= 0x7E) || (secondByte >=80 && secondByte <= 0xFE)) {
           break buildChar;
         }
         // Four byte char
         if (secondByte >= 0x30 && secondByte <= 0x39) {
           thirdByte = iter.nextByte(det);
           if (thirdByte >= 0x81 && thirdByte <= 0xFE) {
             fourthByte = iter.nextByte(det);
             if (fourthByte >= 0x30 && fourthByte <= 0x39) {
               iter.charValue = (iter.charValue << 16) | (thirdByte << 8) | fourthByte;
               break buildChar;
             }
           }
         }
         iter.error = true;
         break buildChar;
       }
     }
     return iter.done == false;
   };

   // TODO:  This set of data comes from the character frequency-
   //        of-occurence analysis tool.  The data needs to be moved
   //        into a resource and loaded from there.
   this.commonChars = [
     0xa1a1, 0xa1a2, 0xa1a3, 0xa1a4, 0xa1b0, 0xa1b1, 0xa1f1, 0xa1f3, 0xa3a1, 0xa3ac,
     0xa3ba, 0xb1a8, 0xb1b8, 0xb1be, 0xb2bb, 0xb3c9, 0xb3f6, 0xb4f3, 0xb5bd, 0xb5c4,
     0xb5e3, 0xb6af, 0xb6d4, 0xb6e0, 0xb7a2, 0xb7a8, 0xb7bd, 0xb7d6, 0xb7dd, 0xb8b4,
     0xb8df, 0xb8f6, 0xb9ab, 0xb9c9, 0xb9d8, 0xb9fa, 0xb9fd, 0xbacd, 0xbba7, 0xbbd6,
     0xbbe1, 0xbbfa, 0xbcbc, 0xbcdb, 0xbcfe, 0xbdcc, 0xbecd, 0xbedd, 0xbfb4, 0xbfc6,
     0xbfc9, 0xc0b4, 0xc0ed, 0xc1cb, 0xc2db, 0xc3c7, 0xc4dc, 0xc4ea, 0xc5cc, 0xc6f7,
     0xc7f8, 0xc8ab, 0xc8cb, 0xc8d5, 0xc8e7, 0xc9cf, 0xc9fa, 0xcab1, 0xcab5, 0xcac7,
     0xcad0, 0xcad6, 0xcaf5, 0xcafd, 0xccec, 0xcdf8, 0xceaa, 0xcec4, 0xced2, 0xcee5,
     0xcfb5, 0xcfc2, 0xcfd6, 0xd0c2, 0xd0c5, 0xd0d0, 0xd0d4, 0xd1a7, 0xd2aa, 0xd2b2,
     0xd2b5, 0xd2bb, 0xd2d4, 0xd3c3, 0xd3d0, 0xd3fd, 0xd4c2, 0xd4da, 0xd5e2, 0xd6d0
   ];
 };
 util.inherits(module.exports.gb_18030, mbcs);
	var util = require('util'),
	Match = require ('../match');

	/**
	* Binary search implementation (recursive)
	*/
	function binarySearch(arr, searchValue) {
	function find(arr, searchValue, left, right) {
	if (right < left)
	return -1;

	/*
	int mid = mid = (left + right) / 2;
	There is a bug in the above line;
	Joshua Bloch suggests the following replacement:
	*/
	var mid = Math.floor((left + right) >>> 1);
	if (searchValue > arr[mid])
	return find(arr, searchValue, mid + 1, right);

	if (searchValue < arr[mid])
	return find(arr, searchValue, left, mid - 1);

	return mid;
	};

	return find(arr, searchValue, 0, arr.length - 1);
	};

	// 'Character' iterated character class.
	// Recognizers for specific mbcs encodings make their 'characters' available
	// by providing a nextChar() function that fills in an instance of iteratedChar
	// with the next char from the input.
	// The returned characters are not converted to Unicode, but remain as the raw
	// bytes (concatenated into an int) from the codepage data.
	//
	// For Asian charsets, use the raw input rather than the input that has been
	// stripped of markup. Detection only considers multi-byte chars, effectively
	// stripping markup anyway, and double byte chars do occur in markup too.
	//
	function IteratedChar() {

	this.charValue = 0; // 1-4 bytes from the raw input data
	this.index = 0;
	this.nextIndex = 0;
	this.error = false;
	this.done = false;

	this.reset = function() {
	this.charValue = 0;
	this.index = -1;
	this.nextIndex = 0;
	this.error = false;
	this.done = false;
	};

	this.nextByte = function(det) {
	if (this.nextIndex >= det.fRawLength) {
	this.done = true;
	return -1;
	}
	var byteValue = det.fRawInput[this.nextIndex++] & 0x00ff;
	return byteValue;
	};
	};



	/**
	* Asian double or multi-byte - charsets.
	* Match is determined mostly by the input data adhering to the
	* encoding scheme for the charset, and, optionally,
	* frequency-of-occurence of characters.
	*/

	function mbcs() {};

	/**
	* Test the match of this charset with the input text data
	* which is obtained via the CharsetDetector object.
	*
	* @param det The CharsetDetector, which contains the input text
	* to be checked for being in this charset.
	* @return Two values packed into one int (Damn java, anyhow)
	* bits 0-7: the match confidence, ranging from 0-100
	* bits 8-15: The match reason, an enum-like value.
	*/
	mbcs.prototype.match = function(det) {

	var singleByteCharCount = 0, //TODO Do we really need this?
	doubleByteCharCount = 0,
	commonCharCount = 0,
	badCharCount = 0,
	totalCharCount = 0,
	confidence = 0;

	var iter = new IteratedChar();

	detectBlock: {
	for (iter.reset(); this.nextChar(iter, det);) {
	totalCharCount++;
	if (iter.error) {
	badCharCount++;
	} else {
	var cv = iter.charValue & 0xFFFFFFFF;

	if (cv <= 0xff) {
	singleByteCharCount++;
	} else {
	doubleByteCharCount++;
	if (this.commonChars != null) {
	// NOTE: This assumes that there are no 4-byte common chars.
	if (binarySearch(this.commonChars, cv) >= 0) {
	commonCharCount++;
	}
	}
	}
	}
	if (badCharCount >= 2 && badCharCount * 5 >= doubleByteCharCount) {
	// console.log('its here!')
	// Bail out early if the byte data is not matching the encoding scheme.
	break detectBlock;
	}
	}

	if (doubleByteCharCount <= 10 && badCharCount== 0) {
	// Not many multi-byte chars.
	if (doubleByteCharCount == 0 && totalCharCount < 10) {
	// There weren't any multibyte sequences, and there was a low density of non-ASCII single bytes.
	// We don't have enough data to have any confidence.
	// Statistical analysis of single byte non-ASCII charcters would probably help here.
	confidence = 0;
	}
	else {
	// ASCII or ISO file? It's probably not our encoding,
	// but is not incompatible with our encoding, so don't give it a zero.
	confidence = 10;
	}
	break detectBlock;
	}

	//
	// No match if there are too many characters that don't fit the encoding scheme.
	// (should we have zero tolerance for these?)
	//
	if (doubleByteCharCount < 20 * badCharCount) {
	confidence = 0;
	break detectBlock;
	}

	if (this.commonChars == null) {
	// We have no statistics on frequently occuring characters.
	// Assess confidence purely on having a reasonable number of
	// multi-byte characters (the more the better
	confidence = 30 + doubleByteCharCount - 20 * badCharCount;
	if (confidence > 100) {
	confidence = 100;
	}
	} else {
	//
	// Frequency of occurence statistics exist.
	//
	var maxVal = Math.log(parseFloat(doubleByteCharCount) / 4);
	var scaleFactor = 90.0 / maxVal;
	confidence = Math.floor(Math.log(commonCharCount + 1) * scaleFactor + 10);
	confidence = Math.min(confidence, 100);
	}
	} // end of detectBlock:

	return confidence == 0 ? null : new Match(det, this, confidence);
	};

	/**
	* Get the next character (however many bytes it is) from the input data
	* Subclasses for specific charset encodings must implement this function
	* to get characters according to the rules of their encoding scheme.
	*
	* This function is not a method of class iteratedChar only because
	* that would require a lot of extra derived classes, which is awkward.
	* @param it The iteratedChar 'struct' into which the returned char is placed.
	* @param det The charset detector, which is needed to get at the input byte data
	* being iterated over.
	* @return True if a character was returned, false at end of input.
	*/

	mbcs.prototype.nextChar = function(iter, det) {};



	/**
	* Shift-JIS charset recognizer.
	*/
	module.exports.sjis = function() {
	this.name = function() {
	return 'Shift-JIS';
	};
	this.language = function() {
	return 'ja';
	};

	// TODO: This set of data comes from the character frequency-
	// of-occurence analysis tool. The data needs to be moved
	// into a resource and loaded from there.
	this.commonChars = [
	0x8140, 0x8141, 0x8142, 0x8145, 0x815b, 0x8169, 0x816a, 0x8175, 0x8176, 0x82a0,
	0x82a2, 0x82a4, 0x82a9, 0x82aa, 0x82ab, 0x82ad, 0x82af, 0x82b1, 0x82b3, 0x82b5,
	0x82b7, 0x82bd, 0x82be, 0x82c1, 0x82c4, 0x82c5, 0x82c6, 0x82c8, 0x82c9, 0x82cc,
	0x82cd, 0x82dc, 0x82e0, 0x82e7, 0x82e8, 0x82e9, 0x82ea, 0x82f0, 0x82f1, 0x8341,
	0x8343, 0x834e, 0x834f, 0x8358, 0x835e, 0x8362, 0x8367, 0x8375, 0x8376, 0x8389,
	0x838a, 0x838b, 0x838d, 0x8393, 0x8e96, 0x93fa, 0x95aa
	];

	this.nextChar = function(iter, det) {
	iter.index = iter.nextIndex;
	iter.error = false;

	var firstByte;
	firstByte = iter.charValue = iter.nextByte(det);
	if (firstByte < 0)
	return false;

	if (firstByte <= 0x7f \|\| (firstByte > 0xa0 && firstByte <= 0xdf))
	return true;

	var secondByte = iter.nextByte(det);
	if (secondByte < 0)
	return false;

	iter.charValue = (firstByte << 8) \| secondByte;
	if (! ((secondByte >= 0x40 && secondByte <= 0x7f) \|\| (secondByte >= 0x80 && secondByte <= 0xff))) {
	// Illegal second byte value.
	iter.error = true;
	}
	return true;
	};
	};
	util.inherits(module.exports.sjis, mbcs);



	/**
	* Big5 charset recognizer.
	*/
	module.exports.big5 = function() {
	this.name = function() {
	return 'Big5';
	};
	this.language = function() {
	return 'zh';
	};
	// TODO: This set of data comes from the character frequency-
	// of-occurence analysis tool. The data needs to be moved
	// into a resource and loaded from there.
	this.commonChars = [
	0xa140, 0xa141, 0xa142, 0xa143, 0xa147, 0xa149, 0xa175, 0xa176, 0xa440, 0xa446,
	0xa447, 0xa448, 0xa451, 0xa454, 0xa457, 0xa464, 0xa46a, 0xa46c, 0xa477, 0xa4a3,
	0xa4a4, 0xa4a7, 0xa4c1, 0xa4ce, 0xa4d1, 0xa4df, 0xa4e8, 0xa4fd, 0xa540, 0xa548,
	0xa558, 0xa569, 0xa5cd, 0xa5e7, 0xa657, 0xa661, 0xa662, 0xa668, 0xa670, 0xa6a8,
	0xa6b3, 0xa6b9, 0xa6d3, 0xa6db, 0xa6e6, 0xa6f2, 0xa740, 0xa751, 0xa759, 0xa7da,
	0xa8a3, 0xa8a5, 0xa8ad, 0xa8d1, 0xa8d3, 0xa8e4, 0xa8fc, 0xa9c0, 0xa9d2, 0xa9f3,
	0xaa6b, 0xaaba, 0xaabe, 0xaacc, 0xaafc, 0xac47, 0xac4f, 0xacb0, 0xacd2, 0xad59,
	0xaec9, 0xafe0, 0xb0ea, 0xb16f, 0xb2b3, 0xb2c4, 0xb36f, 0xb44c, 0xb44e, 0xb54c,
	0xb5a5, 0xb5bd, 0xb5d0, 0xb5d8, 0xb671, 0xb7ed, 0xb867, 0xb944, 0xbad8, 0xbb44,
	0xbba1, 0xbdd1, 0xc2c4, 0xc3b9, 0xc440, 0xc45f
	];
	this.nextChar = function(iter, det) {
	iter.index = iter.nextIndex;
	iter.error = false;

	var firstByte = iter.charValue = iter.nextByte(det);

	if (firstByte < 0)
	return false;

	// single byte character.
	if (firstByte <= 0x7f \|\| firstByte == 0xff)
	return true;

	var secondByte = iter.nextByte(det);

	if (secondByte < 0)
	return false;

	iter.charValue = (iter.charValue << 8) \| secondByte;

	if (secondByte < 0x40 \|\| secondByte == 0x7f \|\| secondByte == 0xff)
	iter.error = true;

	return true;
	};
	};
	util.inherits(module.exports.big5, mbcs);



	/**
	* EUC charset recognizers. One abstract class that provides the common function
	* for getting the next character according to the EUC encoding scheme,
	* and nested derived classes for EUC_KR, EUC_JP, EUC_CN.
	*
	* Get the next character value for EUC based encodings.
	* Character 'value' is simply the raw bytes that make up the character
	* packed into an int.
	*/
	function eucNextChar(iter, det) {
	iter.index = iter.nextIndex;
	iter.error = false;
	var firstByte = 0;
	var secondByte = 0;
	var thirdByte = 0;
	//int fourthByte = 0;
	buildChar: {
	firstByte = iter.charValue = iter.nextByte(det);
	if (firstByte < 0) {
	// Ran off the end of the input data
	iter.done = true;
	break buildChar;
	}
	if (firstByte <= 0x8d) {
	// single byte char
	break buildChar;
	}
	secondByte = iter.nextByte(det);
	iter.charValue = (iter.charValue << 8) \| secondByte;
	if (firstByte >= 0xA1 && firstByte <= 0xfe) {
	// Two byte Char
	if (secondByte < 0xa1) {
	iter.error = true;
	}
	break buildChar;
	}
	if (firstByte == 0x8e) {
	// Code Set 2.
	// In EUC-JP, total char size is 2 bytes, only one byte of actual char value.
	// In EUC-TW, total char size is 4 bytes, three bytes contribute to char value.
	// We don't know which we've got.
	// Treat it like EUC-JP. If the data really was EUC-TW, the following two
	// bytes will look like a well formed 2 byte char.
	if (secondByte < 0xa1) {
	iter.error = true;
	}
	break buildChar;
	}
	if (firstByte == 0x8f) {
	// Code set 3.
	// Three byte total char size, two bytes of actual char value.
	thirdByte = iter.nextByte(det);
	iter.charValue = (iter.charValue << 8) \| thirdByte;
	if (thirdByte < 0xa1) {
	iter.error = true;
	}
	}
	}
	return iter.done == false;
	};



	/**
	* The charset recognize for EUC-JP. A singleton instance of this class
	* is created and kept by the public CharsetDetector class
	*/
	module.exports.euc_jp = function() {
	this.name = function() {
	return 'EUC-JP';
	};
	this.language = function() {
	return 'ja';
	};

	// TODO: This set of data comes from the character frequency-
	// of-occurence analysis tool. The data needs to be moved
	// into a resource and loaded from there.
	this.commonChars = [
	0xa1a1, 0xa1a2, 0xa1a3, 0xa1a6, 0xa1bc, 0xa1ca, 0xa1cb, 0xa1d6, 0xa1d7, 0xa4a2,
	0xa4a4, 0xa4a6, 0xa4a8, 0xa4aa, 0xa4ab, 0xa4ac, 0xa4ad, 0xa4af, 0xa4b1, 0xa4b3,
	0xa4b5, 0xa4b7, 0xa4b9, 0xa4bb, 0xa4bd, 0xa4bf, 0xa4c0, 0xa4c1, 0xa4c3, 0xa4c4,
	0xa4c6, 0xa4c7, 0xa4c8, 0xa4c9, 0xa4ca, 0xa4cb, 0xa4ce, 0xa4cf, 0xa4d0, 0xa4de,
	0xa4df, 0xa4e1, 0xa4e2, 0xa4e4, 0xa4e8, 0xa4e9, 0xa4ea, 0xa4eb, 0xa4ec, 0xa4ef,
	0xa4f2, 0xa4f3, 0xa5a2, 0xa5a3, 0xa5a4, 0xa5a6, 0xa5a7, 0xa5aa, 0xa5ad, 0xa5af,
	0xa5b0, 0xa5b3, 0xa5b5, 0xa5b7, 0xa5b8, 0xa5b9, 0xa5bf, 0xa5c3, 0xa5c6, 0xa5c7,
	0xa5c8, 0xa5c9, 0xa5cb, 0xa5d0, 0xa5d5, 0xa5d6, 0xa5d7, 0xa5de, 0xa5e0, 0xa5e1,
	0xa5e5, 0xa5e9, 0xa5ea, 0xa5eb, 0xa5ec, 0xa5ed, 0xa5f3, 0xb8a9, 0xb9d4, 0xbaee,
	0xbbc8, 0xbef0, 0xbfb7, 0xc4ea, 0xc6fc, 0xc7bd, 0xcab8, 0xcaf3, 0xcbdc, 0xcdd1
	];

	this.nextChar = eucNextChar;
	};
	util.inherits(module.exports.euc_jp, mbcs);



	/**
	* The charset recognize for EUC-KR. A singleton instance of this class
	* is created and kept by the public CharsetDetector class
	*/
	module.exports.euc_kr = function() {
	this.name = function() {
	return 'EUC-KR';
	};
	this.language = function() {
	return 'ko';
	};

	// TODO: This set of data comes from the character frequency-
	// of-occurence analysis tool. The data needs to be moved
	// into a resource and loaded from there.
	this.commonChars = [
	0xb0a1, 0xb0b3, 0xb0c5, 0xb0cd, 0xb0d4, 0xb0e6, 0xb0ed, 0xb0f8, 0xb0fa, 0xb0fc,
	0xb1b8, 0xb1b9, 0xb1c7, 0xb1d7, 0xb1e2, 0xb3aa, 0xb3bb, 0xb4c2, 0xb4cf, 0xb4d9,
	0xb4eb, 0xb5a5, 0xb5b5, 0xb5bf, 0xb5c7, 0xb5e9, 0xb6f3, 0xb7af, 0xb7c2, 0xb7ce,
	0xb8a6, 0xb8ae, 0xb8b6, 0xb8b8, 0xb8bb, 0xb8e9, 0xb9ab, 0xb9ae, 0xb9cc, 0xb9ce,
	0xb9fd, 0xbab8, 0xbace, 0xbad0, 0xbaf1, 0xbbe7, 0xbbf3, 0xbbfd, 0xbcad, 0xbcba,
	0xbcd2, 0xbcf6, 0xbdba, 0xbdc0, 0xbdc3, 0xbdc5, 0xbec6, 0xbec8, 0xbedf, 0xbeee,
	0xbef8, 0xbefa, 0xbfa1, 0xbfa9, 0xbfc0, 0xbfe4, 0xbfeb, 0xbfec, 0xbff8, 0xc0a7,
	0xc0af, 0xc0b8, 0xc0ba, 0xc0bb, 0xc0bd, 0xc0c7, 0xc0cc, 0xc0ce, 0xc0cf, 0xc0d6,
	0xc0da, 0xc0e5, 0xc0fb, 0xc0fc, 0xc1a4, 0xc1a6, 0xc1b6, 0xc1d6, 0xc1df, 0xc1f6,
	0xc1f8, 0xc4a1, 0xc5cd, 0xc6ae, 0xc7cf, 0xc7d1, 0xc7d2, 0xc7d8, 0xc7e5, 0xc8ad
	];

	this.nextChar = eucNextChar;
	};
	util.inherits(module.exports.euc_kr, mbcs);



	/**
	* GB-18030 recognizer. Uses simplified Chinese statistics.
	*/
	module.exports.gb_18030 = function() {
	this.name = function() {
	return 'GB18030';
	};
	this.language = function() {
	return 'zh';
	};

	/*
	* Get the next character value for EUC based encodings.
	* Character 'value' is simply the raw bytes that make up the character
	* packed into an int.
	*/
	this.nextChar = function(iter, det) {
	iter.index = iter.nextIndex;
	iter.error = false;
	var firstByte = 0;
	var secondByte = 0;
	var thirdByte = 0;
	var fourthByte = 0;
	buildChar: {
	firstByte = iter.charValue = iter.nextByte(det);
	if (firstByte < 0) {
	// Ran off the end of the input data
	iter.done = true;
	break buildChar;
	}
	if (firstByte <= 0x80) {
	// single byte char
	break buildChar;
	}
	secondByte = iter.nextByte(det);
	iter.charValue = (iter.charValue << 8) \| secondByte;
	if (firstByte >= 0x81 && firstByte <= 0xFE) {
	// Two byte Char
	if ((secondByte >= 0x40 && secondByte <= 0x7E) \|\| (secondByte >=80 && secondByte <= 0xFE)) {
	break buildChar;
	}
	// Four byte char
	if (secondByte >= 0x30 && secondByte <= 0x39) {
	thirdByte = iter.nextByte(det);
	if (thirdByte >= 0x81 && thirdByte <= 0xFE) {
	fourthByte = iter.nextByte(det);
	if (fourthByte >= 0x30 && fourthByte <= 0x39) {
	iter.charValue = (iter.charValue << 16) \| (thirdByte << 8) \| fourthByte;
	break buildChar;
	}
	}
	}
	iter.error = true;
	break buildChar;
	}
	}
	return iter.done == false;
	};

	// TODO: This set of data comes from the character frequency-
	// of-occurence analysis tool. The data needs to be moved
	// into a resource and loaded from there.
	this.commonChars = [
	0xa1a1, 0xa1a2, 0xa1a3, 0xa1a4, 0xa1b0, 0xa1b1, 0xa1f1, 0xa1f3, 0xa3a1, 0xa3ac,
	0xa3ba, 0xb1a8, 0xb1b8, 0xb1be, 0xb2bb, 0xb3c9, 0xb3f6, 0xb4f3, 0xb5bd, 0xb5c4,
	0xb5e3, 0xb6af, 0xb6d4, 0xb6e0, 0xb7a2, 0xb7a8, 0xb7bd, 0xb7d6, 0xb7dd, 0xb8b4,
	0xb8df, 0xb8f6, 0xb9ab, 0xb9c9, 0xb9d8, 0xb9fa, 0xb9fd, 0xbacd, 0xbba7, 0xbbd6,
	0xbbe1, 0xbbfa, 0xbcbc, 0xbcdb, 0xbcfe, 0xbdcc, 0xbecd, 0xbedd, 0xbfb4, 0xbfc6,
	0xbfc9, 0xc0b4, 0xc0ed, 0xc1cb, 0xc2db, 0xc3c7, 0xc4dc, 0xc4ea, 0xc5cc, 0xc6f7,
	0xc7f8, 0xc8ab, 0xc8cb, 0xc8d5, 0xc8e7, 0xc9cf, 0xc9fa, 0xcab1, 0xcab5, 0xcac7,
	0xcad0, 0xcad6, 0xcaf5, 0xcafd, 0xccec, 0xcdf8, 0xceaa, 0xcec4, 0xced2, 0xcee5,
	0xcfb5, 0xcfc2, 0xcfd6, 0xd0c2, 0xd0c5, 0xd0d0, 0xd0d4, 0xd1a7, 0xd2aa, 0xd2b2,
	0xd2b5, 0xd2bb, 0xd2d4, 0xd3c3, 0xd3d0, 0xd3fd, 0xd4c2, 0xd4da, 0xd5e2, 0xd6d0
	];
	};
	util.inherits(module.exports.gb_18030, mbcs);