10进制和64进制相互转换 php版

使用:表示10以及使用;表示11的原因是根据ascii的排列来选择的，这样要对64进制比较大小，直接比较就可以了。。。

<?php

function dec2s4($dec) {
	$base = '0123456789:;abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';
	$result = '';

	do {
		$result = $base[$dec % 64] . $result;
		$dec = intval($dec / 64);
	} while ($dec != 0);

	return $result;
}

function  s42dec($sixty_four) {
	$base_map = array (
	'0' => 0,
	'1' => 1,
	'2' => 2,
	'3' => 3,
	'4' => 4,
	'5' => 5,
	'6' => 6,
	'7' => 7,
	'8' => 8,
	'9' => 9,
	':' => 10,
	';' => 11,
	'a' => 12,
	'b' => 13,
	'c' => 14,
	'd' => 15,
	'e' => 16,
	'f' => 17,
	'g' => 18,
	'h' => 19,
	'i' => 20,
	'j' => 21,
	'k' => 22,
	'l' => 23,
	'm' => 24,
	'n' => 25,
	'o' => 26,
	'p' => 27,
	'q' => 28,
	'r' => 29,
	's' => 30,
	't' => 31,
	'u' => 32,
	'v' => 33,
	'w' => 34,
	'x' => 35,
	'y' => 36,
	'z' => 37,
	'A' => 38,
	'B' => 39,
	'C' => 40,
	'D' => 41,
	'E' => 42,
	'F' => 43,
	'G' => 44,
	'H' => 45,
	'I' => 46,
	'J' => 47,
	'K' => 48,
	'L' => 49,
	'M' => 50,
	'N' => 51,
	'O' => 52,
	'P' => 53,
	'Q' => 54,
	'R' => 55,
	'S' => 56,
	'T' => 57,
	'U' => 58,
	'V' => 59,
	'W' => 60,
	'X' => 61,
	'Y' => 62,
	'Z' => 63,
	);
	$result = 0;
	$len = strlen($sixty_four);

	for ($n = 0; $n < $len; $n++) {
		$result *= 64;
		$result += $base_map[$sixty_four{$n}];
	}

	return $result;
}

echo s42dec(dec2s4(0));
echo s42dec(dec2s4(10));
echo s42dec(dec2s4(63));
echo s42dec(dec2s4(64));
echo s42dec(dec2s4(111));

评论

1 楼 clllove 2012-11-24