将二进制数转换为Base 64 [英] Convert a binary number to Base 64

问题描述

我知道这是一个非常愚蠢的问题，但是我不知道该怎么办.

I know this is a pretty silly question, but I don't know what to do.

我有一个任意的二进制数，

I have an arbitrary binary number, say,

1001000000110010000000100100000010000011000000010001000001011000110000110000011100011100000011000000010010011000100000000000000100100000010110001100001000000111

我想使用PHP将其转换为Base 64-我尝试的每种方式都给我不同的结果.甚至不同的在线转换器对它的转换也不同:

I want to convert it to Base 64 using PHP - and every way I try gives me a different result. Even different online converters convert it differently:

http://home2.paulschou.net/tools/xlate/
http://convertxy.com/index.php/numberbases/

PHP的base_convert最多只能使用base36，而base64_encode需要一个字符串.

PHP's base_convert only works up to base36, and base64_encode expects a string.

我该怎么办?

更新:我实现了 @binaryLV 建议的解决方案功能，并且运行良好.

UPDATE: I implemented the solution functions suggested by @binaryLV, and it did work well.

但是，我将结果与PHP内置的 base_convert 进行了比较.事实证明，将base_convert转换为base36会返回比自定义base64函数更短的值！ (是的，我确实在所有二进制数字前加了"1"，以确保不会丢失前导零).

However, I compared the results to PHP's built-in base_convert. It turned out that base_convert to base36 returns shorter values that the custom base64 function! (And yes, I did prepend a '1' to all the binary numbers to ensure leading zeros aren't lost).

我也注意到， base_convert 与大量数字无关.因此，我需要一个功能类似于base_convert的函数，但要准确地且最好是直到base 64.

I have noticed, too, that base_convert is quite innacurate with large numbers. So I need is a function which works like base_convert, but accurately and, preferably, up to base 64.

推荐答案

示例中字符串的长度为160.这让我认为它包含有关160/8个字符的信息.所以，

Length of a string in example is 160. It makes me think that it holds info about 160/8 characters. So,

1. 将字符串分割成多个部分，每个部分包含8个二进制数字并描述单个字符
2. 将每个部分转换为十进制整数
3. 使用第二步的ASCII码制作的字符构建字符串

这将与大小为n*8的字符串一起使用.对于其他字符串(例如12个二进制数字)，则会产生意外的结果.

This will work with strings with size n*8. For other strings (e.g., 12 binary digits) it will give unexpected results.

代码:

function bin2base64($bin) {
    $arr = str_split($bin, 8);
    $str = '';
    foreach ( $arr as $binNumber ) {
        $str .= chr(bindec($binNumber));
    }
    return base64_encode($str);
}

$bin = '1001000000110010000000100100000010000011000000010001000001011000110000110000011100011100000011000000010010011000100000000000000100100000010110001100001000000111';
echo bin2base64($bin);

结果:

kDICQIMBEFjDBxwMBJiAASBYwgc=

---

这里还具有将其解码回二进制数字字符串的功能:

---

Here's also function for decoding it back to string of binary digits:

function base64bin($str) {
    $result = '';
    $str = base64_decode($str);
    $len = strlen($str);
    for ( $n = 0; $n < $len; $n++ ) {
        $result .= str_pad(decbin(ord($str[$n])), 8, '0', STR_PAD_LEFT);
    }
    return $result;
}

var_dump(base64bin(bin2base64($bin)) === $bin);

结果:

boolean true

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