一个js写的StringBuffer类

JavaScript StringBuffer 类实现

最新推荐文章于 2025-11-25 11:31:36 发布

最新推荐文章于 2025-11-25 11:31:36 发布 · 121 阅读

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function StringBuffer() {
	this._objArray = [];
	this._undoFlag = false;
};

StringBuffer.prototype.toString = function() {
	if(this._objArray.length==0) {
		return '';
	}
	var str = this._objArray.join('');
	if(this._objArray.length > 1) {
		this.clear();
		this.append(str);
	}
	this._undoFlag = false;
	return str;
};

StringBuffer.prototype.append = function(object) {
	this._objArray[this._objArray.length] = object;
	this._undoFlag = true;
	return this;
};

StringBuffer.prototype.clear = function() {
	this._objArray.length = 0;
	this._undoFlag = false;
};

StringBuffer.prototype.undoLastAppend = function() {
	if(this._undoFlag) {
		this._objArray.length = this._objArray.length -1;
		this._undoFlag = false;
	}
};

StringBuffer.prototype.setSize = function(size) {
	if(size==null || size<=0) {
		this.clear();
		return;
	}
	var str = this._objArray.join('');
	if(size < str.length) {
		str = str.substring(0, size);
		this.clear();
		this.append(str);
	} else if(this._objArray.length > 1) {
		this.clear();
		this.append(str);
	}
	this._undoFlag = false;
};

StringBuffer.prototype.getSize = function() {
	var str = this.toString();
	return str.length;
};