/**
 * 对数据操作操作
 */
public class DataUtil {

    /**
     * 除去0
     */
    public static final int EXCEPT_ZERO = 1;

    /**
     * 获得所有
     */
    public static final int GET_ALL = 0;

    public static byte[] getBytes(byte[] bytes, int start, int size) {
        return getBytes(bytes, start, size, GET_ALL);
    }

    public static byte[] getBytes(byte[] bytes, int start, int size, int type) {
        byte[] resultBytes = new byte[size];
        int current = 0;
        switch (type) {
            case EXCEPT_ZERO:
                int len = 0;
                for (int i = 0 + start; i < size + start; i++) {
                    if (bytes[i] != 0x00) {
                        len++;
                    }
                }
                resultBytes = new byte[len];
                for (int i = 0; i < size; i++) {
                    byte b = bytes[start];
                    if (b != 0x00) {
                        resultBytes[current] = b;
                        current++;
                    }
                    start++;
                }
                return resultBytes;
            case GET_ALL:
                resultBytes = new byte[size];
                for (int i = 0; i < size; i++) {
                    resultBytes[i] = bytes[start];
                    start++;
                }
                return resultBytes;
        }
        return resultBytes;
    }

    /**
     * 切换大小端续
     */
    public static byte[] changeBytes(byte[] a) {
        byte[] b = new byte[a.length];
        for (int i = 0; i < b.length; i++) {
            b[i] = a[b.length - i - 1];
        }
        return b;
    }
}