build/tincan.js
function GB18030Encoder(options, gbk_flag) {
    var fatal = options.fatal;
    // gb18030's decoder has an associated gbk flag (initially unset).
    /**
     * @param {Stream} stream Input stream.
     * @param {number} code_point Next code point read from the stream.
     * @return {(number|!Array.<number>)} Byte(s) to emit.
     */
    this.handler = function(stream, code_point) {
      // 1. If code point is end-of-stream, return finished.
      if (code_point === end_of_stream)
        return finished;

      // 2. If code point is an ASCII code point, return a byte whose
      // value is code point.
      if (isASCIICodePoint(code_point))
        return code_point;

      // 3. If code point is U+E5E5, return error with code point.
      if (code_point === 0xE5E5)
        return encoderError(code_point);

      // 4. If the gbk flag is set and code point is U+20AC, return
      // byte 0x80.
      if (gbk_flag && code_point === 0x20AC)
        return 0x80;

      // 5. Let pointer be the index pointer for code point in index
      // gb18030.
      var pointer = indexPointerFor(code_point, index('gb18030'));

      // 6. If pointer is not null, run these substeps:
      if (pointer !== null) {

        // 1. Let lead be floor(pointer / 190) + 0x81.
        var lead = floor(pointer / 190) + 0x81;

        // 2. Let trail be pointer % 190.
        var trail = pointer % 190;

        // 3. Let offset be 0x40 if trail is less than 0x3F and 0x41 otherwise.
        var offset = trail < 0x3F ? 0x40 : 0x41;

        // 4. Return two bytes whose values are lead and trail + offset.
        return [lead, trail + offset];
      }

      // 7. If gbk flag is set, return error with code point.
      if (gbk_flag)
        return encoderError(code_point);

      // 8. Set pointer to the index gb18030 ranges pointer for code
      // point.
      pointer = indexGB18030RangesPointerFor(code_point);

      // 9. Let byte1 be floor(pointer / 10 / 126 / 10).
      var byte1 = floor(pointer / 10 / 126 / 10);

      // 10. Set pointer to pointer − byte1 × 10 × 126 × 10.
      pointer = pointer - byte1 * 10 * 126 * 10;

      // 11. Let byte2 be floor(pointer / 10 / 126).
      var byte2 = floor(pointer / 10 / 126);

      // 12. Set pointer to pointer − byte2 × 10 × 126.
      pointer = pointer - byte2 * 10 * 126;

      // 13. Let byte3 be floor(pointer / 10).
      var byte3 = floor(pointer / 10);

      // 14. Let byte4 be pointer − byte3 × 10.
      var byte4 = pointer - byte3 * 10;

      // 15. Return four bytes whose values are byte1 + 0x81, byte2 +
      // 0x30, byte3 + 0x81, byte4 + 0x30.
      return [byte1 + 0x81,
              byte2 + 0x30,
              byte3 + 0x81,
              byte4 + 0x30];
    };
  }
function GB18030Encoder(options, gbk_flag) {
    var fatal = options.fatal;
    // gb18030's decoder has an associated gbk flag (initially unset).
    /**
     * @param {Stream} stream Input stream.
     * @param {number} code_point Next code point read from the stream.
     * @return {(number|!Array.<number>)} Byte(s) to emit.
     */
    this.handler = function(stream, code_point) {
      // 1. If code point is end-of-stream, return finished.
      if (code_point === end_of_stream)
        return finished;

      // 2. If code point is an ASCII code point, return a byte whose
      // value is code point.
      if (isASCIICodePoint(code_point))
        return code_point;

      // 3. If code point is U+E5E5, return error with code point.
      if (code_point === 0xE5E5)
        return encoderError(code_point);

      // 4. If the gbk flag is set and code point is U+20AC, return
      // byte 0x80.
      if (gbk_flag && code_point === 0x20AC)
        return 0x80;

      // 5. Let pointer be the index pointer for code point in index
      // gb18030.
      var pointer = indexPointerFor(code_point, index('gb18030'));

      // 6. If pointer is not null, run these substeps:
      if (pointer !== null) {

        // 1. Let lead be floor(pointer / 190) + 0x81.
        var lead = floor(pointer / 190) + 0x81;

        // 2. Let trail be pointer % 190.
        var trail = pointer % 190;

        // 3. Let offset be 0x40 if trail is less than 0x3F and 0x41 otherwise.
        var offset = trail < 0x3F ? 0x40 : 0x41;

        // 4. Return two bytes whose values are lead and trail + offset.
        return [lead, trail + offset];
      }

      // 7. If gbk flag is set, return error with code point.
      if (gbk_flag)
        return encoderError(code_point);

      // 8. Set pointer to the index gb18030 ranges pointer for code
      // point.
      pointer = indexGB18030RangesPointerFor(code_point);

      // 9. Let byte1 be floor(pointer / 10 / 126 / 10).
      var byte1 = floor(pointer / 10 / 126 / 10);

      // 10. Set pointer to pointer − byte1 × 10 × 126 × 10.
      pointer = pointer - byte1 * 10 * 126 * 10;

      // 11. Let byte2 be floor(pointer / 10 / 126).
      var byte2 = floor(pointer / 10 / 126);

      // 12. Set pointer to pointer − byte2 × 10 × 126.
      pointer = pointer - byte2 * 10 * 126;

      // 13. Let byte3 be floor(pointer / 10).
      var byte3 = floor(pointer / 10);

      // 14. Let byte4 be pointer − byte3 × 10.
      var byte4 = pointer - byte3 * 10;

      // 15. Return four bytes whose values are byte1 + 0x81, byte2 +
      // 0x30, byte3 + 0x81, byte4 + 0x30.
      return [byte1 + 0x81,
              byte2 + 0x30,
              byte3 + 0x81,
              byte4 + 0x30];
    };
  }
function GB18030Encoder ( options , gbk_flag ) { var fatal = options . fatal ; // gb18030's decoder has an associated gbk flag (initially unset). /**
     * @param {Stream} stream Input stream.
     * @param {number} code_point Next code point read from the stream.
     * @return {(number|!Array.<number>)} Byte(s) to emit.
     */ this . handler = function ( stream , code_point ) { // 1. If code point is end-of-stream, return finished. if ( code_point === end_of_stream ) return finished ; // 2. If code point is an ASCII code point, return a byte whose // value is code point. if ( isASCIICodePoint ( code_point ) ) return code_point ; // 3. If code point is U+E5E5, return error with code point. if ( code_point === 0xE5E5 ) return encoderError ( code_point ) ; // 4. If the gbk flag is set and code point is U+20AC, return // byte 0x80. if ( gbk_flag && code_point === 0x20AC ) return 0x80 ; // 5. Let pointer be the index pointer for code point in index // gb18030. var pointer = indexPointerFor ( code_point , index ( 'gb18030' ) ) ; // 6. If pointer is not null, run these substeps: if ( pointer !== null ) { // 1. Let lead be floor(pointer / 190) + 0x81. var lead = floor ( pointer / 190 ) + 0x81 ; // 2. Let trail be pointer % 190. var trail = pointer % 190 ; // 3. Let offset be 0x40 if trail is less than 0x3F and 0x41 otherwise. var offset = trail < 0x3F ? 0x40 : 0x41 ; // 4. Return two bytes whose values are lead and trail + offset. return [ lead , trail + offset ] ; } // 7. If gbk flag is set, return error with code point. if ( gbk_flag ) return encoderError ( code_point ) ; // 8. Set pointer to the index gb18030 ranges pointer for code // point. pointer = indexGB18030RangesPointerFor ( code_point ) ; // 9. Let byte1 be floor(pointer / 10 / 126 / 10). var byte1 = floor ( pointer / 10 / 126 / 10 ) ; // 10. Set pointer to pointer − byte1 × 10 × 126 × 10. pointer = pointer - byte1 * 10 * 126 * 10 ; // 11. Let byte2 be floor(pointer / 10 / 126). var byte2 = floor ( pointer / 10 / 126 ) ; // 12. Set pointer to pointer − byte2 × 10 × 126. pointer = pointer - byte2 * 10 * 126 ; // 13. Let byte3 be floor(pointer / 10). var byte3 = floor ( pointer / 10 ) ; // 14. Let byte4 be pointer − byte3 × 10. var byte4 = pointer - byte3 * 10 ; // 15. Return four bytes whose values are byte1 + 0x81, byte2 + // 0x30, byte3 + 0x81, byte4 + 0x30. return [ byte1 + 0x81 , byte2 + 0x30 , byte3 + 0x81 , byte4 + 0x30 ] ; } ; }
11.2.2 gb18030 encoder 
@constructor
@implements {Encoder}
@param {{fatal: boolean}} options
@param {boolean=} gbk_flag
11 . 2 . 2 gb18030 encoder