watch-xdelta
Version:
smart-watch xdelta script
28 lines (24 loc) • 635 B
JavaScript
/**
* 尾部信息相关的操作
*/
;
import {checkSumToHex} from './util';
/**
* 生成尾部信息, 具体结构可以看doc/tail.docx
* @param {Buffer} tail 尾部32字节
* @param {Number} 校验和
* @return {Buffer} 生成的尾部信息
*
*/
export const generatorFooter = function(tail, checksum) {
let {highHex, lowHex} = checkSumToHex(checksum);
//16位校验和的高字节
tail.writeUInt16LE(0, 20);
tail.writeUInt8(0, 22);
tail.writeUInt8(highHex, 23);
//16位校验和的低字节
tail.writeUInt16LE(0, 24);
tail.writeUInt8(0, 26);
tail.writeUInt8(lowHex, 27);
return tail;
};