pbrtools/model/buffer.ts

laya pbr tools

function str2Array(str:string):number[]{
    //var te = window['TextEncoder'];
    var te = require('text-encoding').TextEncoder;
    if(te){
        return (new te()).encode(str) as number[];
    }else{
        throw('no TextEncoder support!')
    }
}


export class BufferReader{
    buff:ArrayBuffer;
    readpos=0;
    viewer:DataView;
    init(buff:ArrayBuffer){
        this.buff=buff;
        this.viewer = new DataView(buff,0);
    }
    readString():string{
        var l = this.viewer.getUint16(this.readpos,true);
        this.readpos+=2;
        var strBuff = this.buff.slice(this.readpos,l+this.readpos);
        this.readpos+=l;
        //var texdec = window['TextDecoder'] as any;
        var texdec = require('text-encoding').TextDecoder;
        var str='';
        if( texdec){
            var dec = new texdec();
            str = dec.decode(new Uint8Array(strBuff))
        }else{
            alert('不支持TextDecoder')
        }
        return str;
        //str = String.fromCharCode.apply(null,
    }

    readU8():number{
        var r = this.viewer.getUint8(this.readpos);
        this.readpos++;
        return r;
    }
    readU16():number{
        var r = this.viewer.getUint16(this.readpos,true);
        this.readpos+=2;
        return r;
    }
    readU32():number{
        var r = this.viewer.getUint32(this.readpos,true);
        this.readpos+=4;
        return r;
    }
    readF32():number{
        var r = this.viewer.getFloat32(this.readpos,true);
        this.readpos+=4;
        return r;
    }
    seek(pos:number){
        this.readpos=pos;
    }
}


/**
 * 字符串的写按照先uint16 len再utf8内容的方式
 */
export class BufferWriter{
    buff:ArrayBuffer;
    datav:DataView;
    _writePos=0;
    nowrite=false;
    constructor(sz?:number){
        if(sz>0){
            this.buff = new ArrayBuffer(sz);
            this.datav = new DataView(this.buff);
        }
    }
    getStrSize(str:string){
        return 2+str2Array(str).length;
    }

    wstr(str:string):BufferWriter{
        var strarr = str2Array(str);
        this.wu16(strarr.length);
        if(!this.nowrite){
            var udata = new Uint8Array(strarr);
            new Uint8Array(this.buff, this._writePos).set(udata);//TODO test
        }
        this._writePos+=strarr.length;
        return this;
    };
    wu16(n:number):BufferWriter{
        if(!this.nowrite) this.datav.setUint16(this._writePos,n,true);
        this._writePos+=2;
        return this;
    };
    wu8(n:number):BufferWriter{
        if(!this.nowrite) this.datav.setUint8(this._writePos,n);
        this._writePos++;
        return this;
    };
    wu32(n:number):BufferWriter{
        if(!this.nowrite) this.datav.setUint32(this._writePos,n,true);
        this._writePos+=4;
        return this;
    };
    wf32(n:number):BufferWriter{ 
        if(!this.nowrite) this.datav.setFloat32(this._writePos,n,true);
        this._writePos+=4;
        return this;
    };
    wab(arraybuffer:ArrayBuffer|DataView, length?:number, offset?:number):BufferWriter {
        if(length==undefined || length==null)
            length = arraybuffer.byteLength;
        if(length==0)return;
        offset = offset ? offset : 0;
        if (length < 0)
            throw "wab error - Out of bounds";
        var ab = null;
        if (arraybuffer instanceof ArrayBuffer)
            ab = arraybuffer;
        else if (arraybuffer.buffer)
            ab = arraybuffer.buffer;
        else
            throw "not arraybuffer/dataview ";
        if(!this.nowrite){
            var uint8array = new Uint8Array(ab, offset, length);
            new Uint8Array(this.buff).set(uint8array,this._writePos);
        }
        this._writePos += length;
        //需要对齐么
        return this;
    }    
}