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lrc paser

lrc 歌词解析播放

Script này sẽ không được không được cài đặt trực tiếp. Nó là một thư viện cho các script khác để bao gồm các chỉ thị meta // @require https://update.greasyfork.ip-ddns.com/scripts/7807/34341/lrc%20paser.js 

/**
 * lrc parser and player
 * @version 0.1.0
 */

var Lrc = (function(){
  Date.now = Date.now || (new Date).getTime;
  var timeExp = /\[(\d{2,})\:(\d{2})(?:\.(\d{2,3}))?\]/g
    , tagsRegMap = {
        title: 'ti'
      , artist: 'ar'
      , album: 'al'
      , offset: 'offset'
      , by: 'by'
    }
    ;
  
  /**
   * lrc parser
   * @param {string} lrc lrc 歌词字符串
   * @param {function} [handler] 
   * @constructor
   */
  var Parser = function(lrc, handler){
    lrc = Parser.trim(lrc);
    this.lrc = lrc;//lrc 歌词
    this.handler = handler || function(){}
    this.tags = {};//ID tags. 标题, 歌手, 专辑
    this.lines = [];//详细的歌词信息
    this.txts = [];
    this.isLrc = Parser.isLrc(lrc);
    
    this.curLine = 0;//
    this.state = 0;// 0: stop, 1: playing
        
    var res, line, time, lines = lrc.split(/\n/)
      , _last;
    
    for(var tag in tagsRegMap){
      res = lrc.match(new RegExp('\\[' + tagsRegMap[tag] + ':([^\\]]*)\\]', 'i'));
      this.tags[tag] = res && res[1] || '';
    }
    
    timeExp.lastIndex = 0;
    for(var i = 0, l = lines.length; i < l; i++){
      while(time = timeExp.exec(lines[i])){
        _last = timeExp.lastIndex;
        line = Parser.trim(lines[i].replace(timeExp, ''));
        timeExp.lastIndex = _last;
        this.lines.push({
            time: time[1] * 60 * 1000 + time[2] * 1000 + (time[3] || 0) * 10
          , originLineNum: i
          , txt: line
        });
        this.txts.push(line);
      }
    }
    
    this.lines.sort(function(a, b){
      return a.time - b.time;
    });
  };
  
  //按照时间点确定歌词行数
  function findCurLine(time){
    for(var i = 0, l = this.lines.length; i < l; i++){
      if(time <= this.lines[i].time){
        break;
      }
    }
    return i;
  }
  
  function focusLine(i){
    this.handler.call(this, this.lines[i].txt, {
        originLineNum: this.lines[i].originLineNum
      , lineNum: i
    })
  }
  
  //lrc stream control and output
  Parser.prototype = {
      //time: 播放起点, skipLast: 是否忽略即将播放歌词的前一条(可能是正在唱的)
      play: function(time, skipLast){
        var that = this;
        
        time = time || 0;
        that._startStamp = Date.now() - time;//相对开始时间戳
        that.state = 1;
        
        if(that.isLrc){
          that.curLine = findCurLine.call(that, time);
          
          if(!skipLast){
            that.curLine && focusLine.call(that, that.curLine - 1);
          }
          
          if(that.curLine < that.lines.length){
          
            clearTimeout(that._timer);
            that._timer = setTimeout(function loopy(){
              focusLine.call(that, that.curLine++);
              
              if(that.lines[that.curLine]){
                that._timer = setTimeout(function(){
                  loopy();
                }, that.lines[that.curLine].time - (Date.now() - that._startStamp));
                //}, that.lines[that.curLine].time - that.lines[that.curLine--].time);//一些情况可能用得上
              }else{
                //end
              }
            }, that.lines[that.curLine].time - time)
          }
        }
      }
    , pauseToggle: function(){
        var now = Date.now();
        if(this.state){
          this.stop();
          this._pauseStamp = now;
        }else{
          this.play((this._pauseStamp || now) - (this._startStamp || now), true);
          delete this._pauseStamp;
        }
      }
    , seek: function(offset){
        this._startStamp -= offset;
        this.state && this.play(Date.now() - this._startStamp);//播放时让修改立即生效
      }
    , stop: function(){
        this.state = 0;
        clearTimeout(this._timer);
      }
  };
    
  Parser.trim = function(lrc){
    return lrc.replace(/(^\s*|\s*$)/m, '')
  };
  Parser.isLrc = function(lrc){
    return timeExp.test(lrc);
  };
  return Parser;
})();

//node.js module
if(typeof module !== 'undefined' && this.module !== module){
  module.exports.Lrc = Lrc;
}