package com.zteits.nbiot.decoder;


import java.util.Arrays;

public class Utilty {

    private static Utilty instance = new Utilty();

    public static Utilty getInstance() {
        return instance;
    }

    public static final int MIN_MID_VALUE = 1;

    public static final int MAX_MID_VALUE = 65535;


    public static int bytes2Int(byte[] b, int start, int length) {
        int sum = 0;
        int end = start + length;
        for (int k = start; k < end; k++) {
            int n = ((int) b[k]) & 0xff;
            n <<= (--length) * 8;
            sum += n;
        }
        return sum;
    }

    public static byte[] int2Bytes(int value, int length) {
        byte[] b = new byte[length];
        for (int k = 0; k < length; k++) {
            b[length - k - 1] = (byte) ((value >> 8 * k) & 0xff);
        }
        return b;
    }

    public boolean isValidofMid(int mId) {
        if (mId < MIN_MID_VALUE || mId > MAX_MID_VALUE) {
            return false;
        }
        return true;
    }

    public static String parseByte2HexStr(byte[] buf) {
        if (null == buf) {
            return null;
        }

        StringBuffer sb = new StringBuffer();
        for (int i = 0; i < buf.length; i++) {
            String hex = Integer.toHexString(buf[i] & 0xFF);
            if (hex.length() == 1) {
                hex = '0' + hex;
            }
            sb.append(hex.toUpperCase());
        }
        return sb.toString();
    }
    /**
     * 16进制转换成为integer
     * @return
     */
    public static Integer hexStringToInteger(byte[] original, int from, int to) {
        String s = Utilty.parseByte2HexStr(Arrays.copyOfRange(original, from, to));
        return Integer.parseInt(s,16);
    }

    /**
     * 16进制转换成为string类型字符串
     * @return
     */
    public static String hexStringToString(byte[] original, int from, int to) {
        String s = Utilty.parseByte2HexStr(Arrays.copyOfRange(original, from, to));
        if (s == null || s.equals("")) {
            return null;
        }
        s = s.replace(" ", "");
        byte[] baKeyword = new byte[s.length() / 2];
        for (int i = 0; i < baKeyword.length; i++) {
            try {
                baKeyword[i] = (byte) (0xff & Integer.parseInt(s.substring(i * 2, i * 2 + 2), 16));
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        try {
            s = new String(baKeyword, "UTF-8");
            new String();
        } catch (Exception e1) {
            e1.printStackTrace();
        }
        return s;
    }
}