QBuffer: A little buffer tool for Node.JS

gistfile1.js

var QBuffer = exports.QBuffer= function(){
	this.list = []
	this.length = 0
}

QBuffer.prototype.append=function(chunk){
	this.list.push(chunk)
	this.length += chunk.length
}

QBuffer.prototype.read=function(N){
	var M = (N<this.length)? N: this.length
	var result =  new Buffer(M)
	var read_count = 0
	while(this.list.length>0){
		if(read_count == M) break;
		var chunk = this.list[0]
		if(chunk.length <= M - read_count){
			chunk.copy(result,read_count,0,chunk.length)
			read_count += chunk.length
			this.list.shift()
		}else{
			need_count = M - read_count
			chunk.copy(result,read_count,0,need_count)
			this.list[0] = this.list[0].slice(need_count)
			break;
		}
	}
	this.length -= M
	return result
}

QBuffer.prototype.search=function(niddle){
	if(typeof niddle == 'string')
		niddle = new Buffer(niddle)
	var i=0
	var j=0
	var k=0
	var last_i=0
	var last_j=0
	var found=false
	var offset = 0
	while(true){
		if(i>=this.list.length)break;
		if(j>=this.list[i].length)break;
		var c = this.list[i][j]
		if(c == niddle[k]){
			if(j<this.list[i].length-1)
				j++
			else{
				i++
				j=0
			}
			k++
			if(k==niddle.length){
				found = true
				break
			}
		}else{
			k = 0
			i = last_i
			j = last_j
			if(j<this.list[i].length-1)
				j++
			else{
				i++
				j=0
			}
			last_i = i 
			last_j = j
			offset++
		}
	}
	if(found)
		return offset
	else
		return -1
}

QBuffer.prototype.readUntil=function(niddle){
	if(typeof niddle == 'string')
		niddle = new Buffer(niddle)
	var offset = this.search(niddle)
	if(offset!=-1)
		return this.read(offset)
	else
		return new Buffer(0)
}

QBuffer.prototype.readUntilOrEnd=function(niddle){
	if(typeof niddle == 'string')
		niddle = new Buffer(niddle)
	var offset = this.search(niddle)
	if(offset!=-1)
		return this.read(offset)
	else
		return this.read(this.length)
}

var QBuffer = require('./qbuffer').QBuffer
var fs = require('fs')
var buf = new QBuffer()
var myfile=fs.createReadStream("hugefile.txt")
myfile.on('data',function(data){
buf.append(data)
var line = null
line = buf.readUntil("\r\n")
if(line.length>0){
console.log(line.toString())
buf.read(2) //skip two bytes of CRLF
}
})
myfile.on('end',function(){
while(buf.length>0){
console.log(buf.readUntilOrEnd("\r\n").toString())
buf.read(2) //skip two bytes of CRLF
}
})