base php,php-baseX
/**
* Created by PhpStorm.
* User: xiongchao
* Date: 2018/7/9
* Time: 14:18
*/
/*
* 思路和普通的十进制转任意进制相同，假设将M进制转N进制，则基本思路为：M/N的余数的N进制表示作为结果的第一位，商的M进制表示作为下一论循环的输入。直到M为0为止。
*/
class BaseX{
/**
* @param string $num
* @param int $m
* @param int $n
* @return string
*/
public function baseConvert(string $num, int $m, int $n)
{
$result = '';
$shang = $num;
while (strlen($shang) > 0) {
$result .= $this->qiuyu($shang, $m, $n);
}
return strrev($result);
}
private function qiuyu(string &$num, int $m, int $n)
{
$remain = 0;
$shang = '';
for ($i = 0; $i < strlen($num); $i++) {
$remain = $remain * $m + $this->getIntFromStr($num[$i]);
$shang .= $this->getStrFromInt(intval($remain / $n));
$remain = $remain % $n;
}
while (strlen($shang) > 0 && $shang[0] == '0') {
$shang = substr($shang, 1);
}
$num = $shang;
return $this->getStrFromInt($remain);
}
private function getIntFromStr($value)
{
if ($value >= '0' && $value <= '9')
return $value - 0;
if ($value >= 'a' && $value <= 'z')
return (ord($value) - ord('a')) + 10;
}
private function getStrFromInt(int $value)
{
if ($value >= 0 && $value <= 9)
return (string)$value;
if ($value >= 10 && $value <= 35)
return chr(97 + ($value - 10));
else
throw new Exception("output $value");
}
/**
* 依赖gmp扩展,该方法性能较好
* @param string $num
* @param $base
* @param $toBase
* @return string
*/
public function gmp_convert(string $num,$base,$toBase){
return gmp_strval(gmp_init($num,$base),$toBase);
}
}