com.gitee.apanlh.util.encode.BcdUtils Maven / Gradle / Ivy
package com.gitee.apanlh.util.encode;
/**
* BCD码（Binary-Coded Decimal）亦称二进码十进数或二-十进制代码
* BCD码这种编码形式利用了四个位元来储存一个十进制的数码，使二进制和十进制之间的转换得以快捷的进行
* http://cuisuqiang.iteye.com/blog/1429956
*
* @author PAN
*/
public class BcdUtils {
/**
* 构造函数
*
* @author Pan
*/
private BcdUtils() {
// 不允许外部实例
super();
}
/**
* 字符串转BCD码
*
* @param asc ASCII字符串
* @return BCD
*/
public static byte[] strToBcd(String asc) {
int len = asc.length();
int mod = len % 2;
if (mod != 0) {
asc = "0" + asc;
len = asc.length();
}
byte[] abt;
if (len >= 2) {
len >>= 1;
}
byte[] bbt;
bbt = new byte[len];
abt = asc.getBytes();
int j;
int k;
for (int p = 0; p < asc.length() / 2; p++) {
if ((abt[2 * p] >= '0') && (abt[2 * p] <= '9')) {
j = abt[2 * p] - '0';
} else if ((abt[2 * p] >= 'a') && (abt[2 * p] <= 'z')) {
j = abt[2 * p] - 'a' + 0x0a;
} else {
j = abt[2 * p] - 'A' + 0x0a;
}
if ((abt[2 * p + 1] >= '0') && (abt[2 * p + 1] <= '9')) {
k = abt[2 * p + 1] - '0';
} else if ((abt[2 * p + 1] >= 'a') && (abt[2 * p + 1] <= 'z')) {
k = abt[2 * p + 1] - 'a' + 0x0a;
} else {
k = abt[2 * p + 1] - 'A' + 0x0a;
}
int a = (j << 4) + k;
byte b = (byte) a;
bbt[p] = b;
}
return bbt;
}
/**
* ASCII转BCD
*
* @param ascii ASCII byte数组
* @return BCD
*/
public static byte[] ascToBcd(byte[] ascii) {
return ascToBcd(ascii, ascii.length);
}
/**
* ASCII转BCD
*
* @param ascii ASCII byte数组
* @param ascLength 长度
* @return BCD
*/
public static byte[] ascToBcd(byte[] ascii, int ascLength) {
byte[] bcd = new byte[ascLength / 2];
int j = 0;
for (int i = 0; i < (ascLength + 1) / 2; i++) {
bcd[i] = ascToBcd(ascii[j++]);
int a1 = ((j >= ascLength) ? 0x00 : ascToBcd(ascii[j++]));
bcd[i] = (byte) (a1 + (bcd[i] << 4));
}
return bcd;
}
/**
* BCD转ASCII字符串
*
* @param bytes BCD byte数组
* @return ASCII字符串
*/
public static String bcdToStr(byte[] bytes) {
char[] temp = new char[bytes.length * 2];
char val;
for (int i = 0; i < bytes.length; i++) {
val = (char) (((bytes[i] & 0xf0) >> 4) & 0x0f);
temp[i * 2] = (char) (val > 9 ? val + 'A' - 10 : val + '0');
val = (char) (bytes[i] & 0x0f);
temp[i * 2 + 1] = (char) (val > 9 ? val + 'A' - 10 : val + '0');
}
return new String(temp);
}
/**
* 转换单个byte为BCD
*
* @param asc ASCII
* @return BCD
*/
private static byte ascToBcd(byte asc) {
if ((asc >= '0') && (asc <= '9')) {
return (byte) (asc - '0');
}
if ((asc >= 'A') && (asc <= 'F')) {
return (byte) (asc - 'A' + 10);
}
if ((asc >= 'a') && (asc <= 'f')) {
return (byte) (asc - 'a' + 10);
}
return (byte) (asc - 48);
}
}