在PHP中将64位二进制字符串转换为16个字符的十六进制

Question

I have a 64 character long string, like the following: 0100101000000011111010000101010000111101000011010100010000100110 That I need to end up in what I believe is a hexidecimal string that is 18 characters long: 084a0002d43d0d4426 .

The code that currently does this in C# looks like this:

private string BinaryStringToHexString(string binary)
{
    StringBuilder result = new StringBuilder(binary.Length / 8 + 1);

    for (int i = 0; i < binary.Length; i += 8)
    {
        string eightBits = binary.Substring(i, 8);
        result.AppendFormat("{0:X2}", Convert.ToByte(eightBits, 2));
    }

    return result.ToString();
}

I'm trying to figure out how this is achieved in PHP, but when using the dechex or binhex functions in php the format does not end up similar. Here is my current attempt in PHP:

$fullStringToEncode = '0100101000000011111010000101010000111101000011010100010000100110';

for ($i = 0; $i < strlen($fullStringToEncode); $i = $i + 8) {
    $eightBits = substr($fullStringToEncode, $i, 8);
    $result .= sprintf("%02X", dechex($eightBits));
}

The above php code gives me 020282220222124a2 which is 17 characters long.

This was based on a few days of googling and trying to figure it out. Can anyone see where I'm going wrong?

Answer 1

The input string you currently have 0100101000000011111010000101010000111101000011010100010000100110 will be converted to 4A03E8543D0D4426 , you can confirm this with the C# snippet you have or do the conversion by hand. In order to produce 084a0002d43d0d4426 your input should be 000010000100101000000000000000101101010000111101000011010100010000100110 .

That being said, dechex(int $number) returns a string containing the hex representation of $number . Instead of dechex , you can use bindec( string $binary_string) which will return the decimal equivalent of the binary number represented by the $binary_string argument. Modify your code to use bindec :

<?php
    $fullStringToEncode = '000010000100101000000000000000101101010000111101000011010100010000100110';

    $result = '';
    for ($i = 0; $i < strlen($fullStringToEncode); $i = $i + 8) {
        $eightBits = substr($fullStringToEncode, $i, 8);
        $result .= sprintf('%02X', bindec($eightBits));
    }
    echo $result;
?>

Outputs:

084A0002D43D0D4426