Auth_OpenID_MathLibrary Class Reference

Inheritance diagram for Auth_OpenID_MathLibrary:

Collaboration diagram for Auth_OpenID_MathLibrary:

Public Member Functions
	longToBinary ($long)
	Given a long integer, returns the number converted to a binary string. More...
	binaryToLong ($str)
	Given a binary string, returns the binary string converted to a long number. More...
	base64ToLong ($str)
	longToBase64 ($str)
	rand ($stop)
	Returns a random number in the specified range. More...

Detailed Description

Definition at line 33 of file BigMath.php.

Member Function Documentation

base64ToLong()

Auth_OpenID_MathLibrary::base64ToLong

(

$str

)

Definition at line 112 of file BigMath.php.

References binaryToLong().

    {
        $b64 = base64_decode($str);

        if ($b64 === false) {
            return false;
        }

        return $this->binaryToLong($b64);
    }

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binaryToLong()

Auth_OpenID_MathLibrary::binaryToLong

(

$str

)

Given a binary string, returns the binary string converted to a long number.

Parameters

string

$binary

The binary version of a long number, probably as a result of calling longToBinary

Returns

integer $long The long number equivalent of the binary string $str

Definition at line 86 of file BigMath.php.

References $n.

Referenced by base64ToLong(), and rand().

    {
        if ($str === null) {
            return null;
        }

        // Use array_merge to return a zero-indexed array instead of a
        // one-indexed array.
        $bytes = array_merge(unpack('C*', $str));

        $n = $this->init(0);

        if ($bytes && ($bytes[0] > 127)) {
            trigger_error("bytesToNum works only for positive integers.",
                          E_USER_WARNING);
            return null;
        }

        foreach ($bytes as $byte) {
            $n = $this->mul($n, pow(2, 8));
            $n = $this->add($n, $byte);
        }

        return $n;
    }

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longToBase64()

Auth_OpenID_MathLibrary::longToBase64

(

$str

)

Definition at line 123 of file BigMath.php.

References longToBinary().

    {
        return base64_encode($this->longToBinary($str));
    }

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longToBinary()

Auth_OpenID_MathLibrary::longToBinary

(

$long

)

Given a long integer, returns the number converted to a binary string.

This function accepts long integer values of arbitrary magnitude and uses the local large-number math library when available.

Parameters

integer

$long

The long number (can be a normal PHP integer or a number created by one of the available long number libraries)

Returns

string $binary The binary version of $long

Definition at line 45 of file BigMath.php.

Referenced by longToBase64(), and rand().

    {
        $cmp = $this->cmp($long, 0);
        if ($cmp < 0) {
            $msg = __FUNCTION__ . " takes only positive integers.";
            trigger_error($msg, E_USER_ERROR);
            return null;
        }

        if ($cmp == 0) {
            return "\x00";
        }

        $bytes = array();

        while ($this->cmp($long, 0) > 0) {
            array_unshift($bytes, $this->mod($long, 256));
            $long = $this->div($long, pow(2, 8));
        }

        if ($bytes && ($bytes[0] > 127)) {
            array_unshift($bytes, 0);
        }

        $string = '';
        foreach ($bytes as $byte) {
            $string .= pack('C', $byte);
        }

        return $string;
    }

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rand()

Auth_OpenID_MathLibrary::rand

(

$stop

)

Returns a random number in the specified range.

This function accepts $start, $stop, and $step values of arbitrary magnitude and will utilize the local large-number math library when available.

Parameters

integer	$start	The start of the range, or the minimum random number to return
integer	$stop	The end of the range, or the maximum random number to return
integer	$step	The step size, such that $result - ($step N) = $start for some N

Returns

integer $result The resulting randomly-generated number

Definition at line 142 of file BigMath.php.

References $n, binaryToLong(), Auth_OpenID\bytes(), Auth_OpenID_CryptUtil\getBytes(), and longToBinary().

    {
        static $duplicate_cache = array();

        // Used as the key for the duplicate cache
        $rbytes = $this->longToBinary($stop);

        if (array_key_exists($rbytes, $duplicate_cache)) {
            list($duplicate, $nbytes) = $duplicate_cache[$rbytes];
        } else {
            if ($rbytes[0] == "\x00") {
                $nbytes = Auth_OpenID::bytes($rbytes) - 1;
            } else {
                $nbytes = Auth_OpenID::bytes($rbytes);
            }

            $mxrand = $this->pow(256, $nbytes);

            // If we get a number less than this, then it is in the
            // duplicated range.
            $duplicate = $this->mod($mxrand, $stop);

            if (count($duplicate_cache) > 10) {
                $duplicate_cache = array();
            }

            $duplicate_cache[$rbytes] = array($duplicate, $nbytes);
        }

        do {
            $bytes = "\x00" . Auth_OpenID_CryptUtil::getBytes($nbytes);
            $n = $this->binaryToLong($bytes);
            // Keep looping if this value is in the low duplicated range
        } while ($this->cmp($n, $duplicate) < 0);

        return $this->mod($n, $stop);
    }

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The documentation for this class was generated from the following file:

• Services/OpenId/lib/Auth/OpenID/BigMath.php