PHP bcd code compression - compress decimal numbers into hexadecimal data

PHP bcd code compression - compress decimal numbers into hexadecimal data_PHP tutorial

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Release： 2016-07-13 10:44:21

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Example, php bcd code compression - compress decimal numbers into hexadecimal data

代码如下

复制代码

/*
php bcd码压缩-把十进制数字压缩到十六进制数据中
例如 0091 压缩后 0x00 0x91
*/
$string = '0091';
$bytes = Bytes::getBytes($string);
print_r($bytes);
/*
Array
(

[0] => 48

[1] => 48

[2] => 57

[3] => 49
)
*/
$asc=Bytes::AscToHex($bytes,4);
//4位压缩成2位
print_r($asc);
/*
Array
(

[0] => 0

[1] => 145
)
*/
echo Bytes::toStr($asc);
/*
0091
*/
$hex=Bytes::HexToAsc($asc,2);
//反操作2位还原成4位
print_r($hex);
/*
Array
(

[0] => 48

[1] => 48

[2] => 57

[3] => 49
)
*/
?>

Example, compress decimal numbers into hexadecimal data

代码如下

复制代码

/**

*php bcd code compression

* Compress decimal numbers into hexadecimal data

* @author phpff.com

* Created on 2011-7-15

*/
class Bytes {

/**

* Convert a String to a byte array

* @param $str The string to be converted

* @param $bytes target byte array

* @author phpff.com

*/
    public static function getBytes($string) {

        $bytes = array();
        for($i = 0; $i < strlen($string); $i++){
             $bytes[] = ord($string[$i]);
        }
        return $bytes;
    }


/**

* Convert byte array to String type data

* @param $bytes byte array

* @param $str target string

* @return a String type data

*/

    public static function toStr($bytes) {
        $str = '';
        foreach($bytes as $ch) {
            $str .= bin2hex(chr($ch));
        }

           return $str;
    }


/**

* Convert asc code to hexadecimal data

* @param $asc asc numeric string

* @param $AscLen The length of the string to be converted

* @return hexadecimal array

* @author phpff.com

*/
     public static function AscToHex( $asc, $AscLen) {
        $i=0;
        $Hex=array();
        for($i = 0; 2*$i < $AscLen; $i++)
        {

/*A:0x41(0100 0001),a:0x61(0110 0001),右移4位后都是0001,加0x90等0xa*/
            $Hex[$i] = (chr($asc[2*$i]) << 4);
            if (!(chr($asc[2*$i]) >= '0' && chr($asc[2*$i]) <= '9' )){
                $Hex[$i] += 0x90;
            }

            if(2*$i+1 >= $AscLen){
                break;
            }

            $Hex[$i] |= (chr($asc[2*$i+1]) & 0x0f);
            if (!(chr($asc[2*$i+1]) >= '0' && chr($asc[2*$i+1]) <= '9' )){
                $Hex[$i] += 0x09;
            }

        }
        return $Hex;
    }

/**

* 将16进制的数据转换成asc码

* @param $Hex 16进制数组

* @param $HexLen 16进制数组长度

* @return asc数组

* @author phpff.com

*/
    public static function HexToAsc($Hex, $HexLen) {
        $i=0;
        $Temp=0;
        for($i = 0; $i < $HexLen; $i++ )
        {
            $Temp = ($Hex[$i] & 0xf0) >> 4;
            if ($Temp < 10){
                $Asc[2*$i] = (0x30 + $Temp);
            }else{
                $Asc[2*$i] =   (0x37 + $Temp);
            }

            $Temp = $Hex[$i] & 0x0f;
            if ($Temp < 10){
                $Asc[2*$i+1] = (0x30 + $Temp);
            }else{
                $Asc[2*$i+1] = (0x37 + $Temp);
            }

        }
        return $Asc;
    }

}
?>