ParagonIE_Sodium_Core_Base64_UrlSafe::decode() public WP 1.0

decode from base64 into binary

Base64 character set "./[A-Z][a-z][0-9]"

{} It's a method of the class: ParagonIE_Sodium_Core_Base64_UrlSafe{}

No Hooks.

Return

String.

Usage

$result = ParagonIE_Sodium_Core_Base64_UrlSafe::decode( $src, $strictPadding );

$src(string) (required)

-

Default: false

Code of ParagonIE_Sodium_Core_Base64_UrlSafe::decode() ParagonIE Sodium Core Base64 UrlSafe::decode ^{WP 5.8.2}

public static function decode($src, $strictPadding = false)
{
    // Remove padding
    $srcLen = ParagonIE_Sodium_Core_Util::strlen($src);
    if ($srcLen === 0) {
        return '';
    }

    if ($strictPadding) {
        if (($srcLen & 3) === 0) {
            if ($src[$srcLen - 1] === '=') {
                $srcLen--;
                if ($src[$srcLen - 1] === '=') {
                    $srcLen--;
                }
            }
        }
        if (($srcLen & 3) === 1) {
            throw new RangeException(
                'Incorrect padding'
            );
        }
        if ($src[$srcLen - 1] === '=') {
            throw new RangeException(
                'Incorrect padding'
            );
        }
    } else {
        $src = rtrim($src, '=');
        $srcLen =  ParagonIE_Sodium_Core_Util::strlen($src);
    }

    $err = 0;
    $dest = '';
    // Main loop (no padding):
    for ($i = 0; $i + 4 <= $srcLen; $i += 4) {
        /** @var array<int, int> $chunk */
        $chunk = unpack('C*', ParagonIE_Sodium_Core_Util::substr($src, $i, 4));
        $c0 = self::decode6Bits($chunk[1]);
        $c1 = self::decode6Bits($chunk[2]);
        $c2 = self::decode6Bits($chunk[3]);
        $c3 = self::decode6Bits($chunk[4]);

        $dest .= pack(
            'CCC',
            ((($c0 << 2) | ($c1 >> 4)) & 0xff),
            ((($c1 << 4) | ($c2 >> 2)) & 0xff),
            ((($c2 << 6) | $c3) & 0xff)
        );
        $err |= ($c0 | $c1 | $c2 | $c3) >> 8;
    }
    // The last chunk, which may have padding:
    if ($i < $srcLen) {
        /** @var array<int, int> $chunk */
        $chunk = unpack('C*', ParagonIE_Sodium_Core_Util::substr($src, $i, $srcLen - $i));
        $c0 = self::decode6Bits($chunk[1]);

        if ($i + 2 < $srcLen) {
            $c1 = self::decode6Bits($chunk[2]);
            $c2 = self::decode6Bits($chunk[3]);
            $dest .= pack(
                'CC',
                ((($c0 << 2) | ($c1 >> 4)) & 0xff),
                ((($c1 << 4) | ($c2 >> 2)) & 0xff)
            );
            $err |= ($c0 | $c1 | $c2) >> 8;
        } elseif ($i + 1 < $srcLen) {
            $c1 = self::decode6Bits($chunk[2]);
            $dest .= pack(
                'C',
                ((($c0 << 2) | ($c1 >> 4)) & 0xff)
            );
            $err |= ($c0 | $c1) >> 8;
        } elseif ($i < $srcLen && $strictPadding) {
            $err |= 1;
        }
    }
    /** @var bool $check */
    $check = ($err === 0);
    if (!$check) {
        throw new RangeException(
            'Base64::decode() only expects characters in the correct base64 alphabet'
        );
    }
    return $dest;
}