package com.sandu.ximon.admin.manager.iot.rrpc.util;

/**
 * @author chenjiantian
 */
public class SupplementUtils {


    /**
     * 截取指定长度的字符串，不足以0填充前面
     * @param hex 字符串
     * @param totalBit 截取长度
     * @return 截取后的字符串
     */
    public static String suppleZero(String hex, Integer totalBit) {

        if (hex.length() > totalBit) {
            return hex.substring(0, totalBit);
        } else if (hex.length() == totalBit) {
            return hex;
        }
        totalBit = totalBit - hex.length();

        StringBuilder hexBuilder = new StringBuilder(hex);
        for (int i = 0; i < totalBit; i++) {
            hexBuilder.insert(0, "0");
        }
        hex = hexBuilder.toString();
        return hex;
    }


}