node（Buffer缓存区）

// 创建buffer类
var buf=new buffer(10);
var buf=new buffer([10,20,30,40]);
var buf=new buffer("www.baidu.com","utf-8");
// 写入缓存区
buf.write(string[,offset[,length]][encoding])
buf=new buffer(256);
len=buf.write("www.runoob.com")
console,log("写入字节数："+len)
// 从缓存读取数据
buf.toString([encoding[,start[,end]]])
buf=new buffer(26);
for(var i=0;i<26;i++;){
buf[i]=i+97;
}
console.log(buf.toString('ascill'));
console.log(buf.toString('ascill',0,5))
console.log(buf.toString('utf-8',0,5))
console.log(buf.toString('undefined',0,5))
// 转为json
buf.toJSON()
var buf=new buffer('www.baidu.com');
var json=buf.toJSON('buf')
console.log(json)
// 缓存合并
buffer.concat(list[,totalLength]);
var buffer1=new Buffer('菜鸟教程');
var buffer2=new Buffer('www.runoob.com');
var buffer3=Buffer.concat([buffer1,buffer2]);
console.log("buffer3内容"+buffer3.toString())
// 缓存区比较
buf.compare(otherBuffer)
var buffer1=new Buffer('ABC');
var buffer2=new Buffer('ABCD');
var result=buffer1.compare(buffer2);
if(result<0){
console.log(buffer1+"在"+buffer2+"之前")
}else if(result==0){
console.log(buffer1+"等于"+buffer)
}else{
console.log(buffer1+"在"+buffer2+"之后")
}
// 拷贝缓存区
buf.copy(targetBuffer[,targetStart[,sourceStart[,sourcEnd]]])
var buffer1=new Buffer('ABC');
var buffer2=new Buffer(3);
buffer1.copy(Buffer2);
console.log("buffer2 content:"+buffer2.toString())
// 缓存区裁剪
buf.slice([start[,end]])
var buffer1=new Buffer('runoob')
var buffer2=buffer1.slice(0,2);
console.log("buffer2 content:"+buffer2.toString());
buffer2 content:ru
// 缓存区长度
buf.length
var buffer=new Buffer("www.runoob.com");
console.log("buffer length:"+buffer.length)
buffer length:14