[edit] Last updated: Mon, 01 Nov 2010

XLVIII. GMP Functions

Wstęp

These functions allow you to work with arbitrary-length integers using the GNU MP library.

These functions have been added in PHP 4.0.4.

Notatka: Most GMP functions accept GMP number arguments, defined as resource below. However, most of these functions will also accept numeric and string arguments, given that it is possible to convert the latter to a number. Also, if there is a faster function that can operate on integer arguments, it would be used instead of the slower function when the supplied arguments are integers. This is done transparently, so the bottom line is that you can use integers in every function that expects GMP number. See also the gmp_init() function.

Ostrzeżenie

If you want to explicitly specify a large integer, specify it as a string. If you don't do that, PHP will interpret the integer-literal first, possibly resulting in loss of precision, even before GMP comes into play.

Notatka: This extension is available on Windows platforms since PHP 5.1.0.

Wymagania

You can download the GMP library from http://www.swox.com/gmp/. This site also has the GMP manual available.

You will need GMP version 2 or better to use these functions. Some functions may require more recent version of the GMP library.

Instalacja

In order to have these functions available, you must compile PHP with GMP support by using the --with-gmp option.

Konfiguracja czasu wykonywania

To rozszerzenie nie definiuje posiada żadnych dyrektyw konfiguracyjnych w pliku php.ini.

Typy zasobów

To rozszerzenie nie posiada żadnych rodzajów zasobów.

Stałe predefinopwane

Poniższe stałe są zdefiniowane w tym rozszerzeniu i stają się dostępne, gdy rozszerzenie jest dokompilowane do PHP, lub załadowane dynamicznie przy starcie.

GMP_ROUND_ZERO (integer)
GMP_ROUND_PLUSINF (integer)
GMP_ROUND_MINUSINF (integer)

Przykłady

Przykład 1. Factorial function using GMP


<?php

function fact($x) 

{

    $return = 1;

    for ($i=2; $i < $x; $i++) {

        $return = gmp_mul($return, $i);

    }

    return $return;

}



echo gmp_strval(fact(1000)) . "\n";

?>

This will calculate factorial of 1000 (pretty big number) very fast.

Patrz także

More mathematical functions can be found in the sections BCMath Arbitrary Precision Mathematics Functions and Mathematical Functions.

Spis treści
gmp_abs -- Absolute value
gmp_add -- Add numbers
gmp_and -- Logical AND
gmp_clrbit -- Clear bit
gmp_cmp -- Compare numbers
gmp_com -- Calculates one's complement
gmp_div_q -- Divide numbers
gmp_div_qr -- Divide numbers and get quotient and remainder
gmp_div_r -- Remainder of the division of numbers
gmp_div -- Alias dla gmp_div_q()
gmp_divexact -- Exact division of numbers
gmp_fact -- Factorial
gmp_gcd -- Calculate GCD
gmp_gcdext -- Calculate GCD and multipliers
gmp_hamdist -- Hamming distance
gmp_init -- Create GMP number
gmp_intval -- Convert GMP number to integer
gmp_invert -- Inverse by modulo
gmp_jacobi -- Jacobi symbol
gmp_legendre -- Legendre symbol
gmp_mod -- Modulo operation
gmp_mul -- Multiply numbers
gmp_neg -- Negate number
gmp_nextprime -- Find next prime number
gmp_or -- Logical OR
gmp_perfect_square -- Perfect square check
gmp_popcount -- Population count
gmp_pow -- Raise number into power
gmp_powm -- Raise number into power with modulo
gmp_prob_prime -- Check if number is "probably prime"
gmp_random -- Random number
gmp_scan0 -- Scan for 0
gmp_scan1 -- Scan for 1
gmp_setbit -- Set bit
gmp_sign -- Sign of number
gmp_sqrt -- Calculate square root
gmp_sqrtrem -- Square root with remainder
gmp_strval -- Convert GMP number to string
gmp_sub -- Subtract numbers
gmp_xor -- Logical XOR

gmp_abs

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[edit] Last updated: Mon, 01 Nov 2010

add a note User Contributed Notes GMP Functions

Nitrogen 06-Sep-2010 08:02


I made a function that can be used for converting numbers to any base you wish.. instead of returning a string of pre-defined index of characters (i.e. 0-9a-z) you could simply make your own of any length using the array of indexes it returns.


I looked around and didn't see anybody made one, I needed one for a simple compression algorithm with only numbers, I've not actually made it yet but this was an initial idea.





<?php


// ConvertBase function explained:


// we add an array item $Input%$Base floored and divide $Input by $Base floored.


// repeat until $Input is no longer above 0.





function ConvertBase($Input,$Base=10) {


  $Input=gmp_init($Input);


  $Result=array();





  for($i=0;$i<1||gmp_sign($Input)==1;$i++) {


    $Result[]=gmp_intval(gmp_mod($Input,$Base));


    $Input=gmp_div_q($Input,$Base);


  }


  $Result=array_reverse($Result);


  return($Result);


}





// an example how gmp_strval($.., 36); could be achieved:





// the funny emergency number from The IT Crowd


// (leading zeroes aren't liked in gmp_init though)


$Input = '1189998819991197253';





// our example 36 characters used in gmp_strval($.., 36);


$Chars = '0123456789abcdefghijklmnopqrstuvwxyz';





// count the $Chars so they're all used


// or use your own number less than the length of $Chars


$Base = strlen($Chars);





// perform


$Result = ConvertBase($Input,$Base);





// replace the resulting index with the corrosponding characters of the index in $Chars


for($i=0;$i<count($Result);$i++)


  $Result[$i]=$Chars{$Result[$i]};





// compare


printf("gmp_strval:  %s\r\n",gmp_strval($Input,36));


printf("BaseConvert: %s\r\n",implode($Result));





/* OUTPUT:


gmp_strval:  91h7dixfq6h1


BaseConvert: 91h7dixfq6h1


*/


?>


The example shows a familiar result of course, but the idea of this function was so that you can use whatever base you wish, and display entirely your own output to represent any number of choice.





Also, for those who wish to do bitwise shifting, it's quite simple.. to shift left, just multiply the number by pow(2,x), and to shift right, divide by pow(2,x).





<?php


function gmp_shiftl($x,$n) { // shift left


  return(gmp_mul($x,gmp_pow(2,$n)));


}





function gmp_shiftr($x,$n) { // shift right


  return(gmp_div($x,gmp_pow(2,$n)));


}


?>





Have fun,


Nitrogen.

john at worldmapad dot com 22-Jul-2006 11:24


Here's a quick and dirty way to use simple GMP functions with PHP without recompiling. It is dependent upon the use of the exec() function, so make sure you can use exec(). While in safe mode you must consider the safe_mode_exec_dir directive. And don't simply pass user input to the exec function without validating the input first!



Download and Install GMP as instructed in README and INSTALL files.

On my MAC OS X Server, I just did the following:

./configure

make

make check

make install

This installed it in the /usr/local directory. There were some errors, but not with any functions I needed.

Within the gmp-4.#.# cd into the demos directory. Then compile pexpr.c by typing:

make pexpr

This is a simple expressions parser which serves as a simple interface to some of the basic GMP functions.

You can test it then like:

./pexpr "102394874783 * 23498748";

Now you may interface with it using PHP's exec() function.

richard-slater.co.uk 22-Feb-2004 01:03


For those (like me) who are trying to do bit masking with very large numbers, here is a useful function to do the work for you.



<?php

  function isBitSet($bitMask, $bitMap)

  {

    return (bool) gmp_intval(gmp_div(gmp_and($bitMask, $bitMap),$bitMask));

  }

?>

helvecio_oliveira at yahoo dot com dot br 15-Oct-2003 01:51


=============================================================

A set of very nice functions to handle IP Address with gmplib:



The best way to store a range into a database is store:

dNet ..... decimal representation of a Net

dMask .... decimal representation of a Mask



All another parameters can be calculated.



<?

/*

f_ip2dec($a) ................... IP string to decimal

f_dec2ip($a) ................... decimal to IP string



f_dec2ipall($dNet,$dMask) ...... decimal Net and Mask to an Array with several IP parameters



f_dec2cidr($a) ................. decimal Mask to CIDR



f_and($a,$b) ................... and

f_or($a,$b) .................... or

f_xor($a,$b) ................... xor

f_not($a) ...................... not

f_dec2bin($a) .................. decimal to binary string

f_bin2dec($a) .................. binary string to decimal

*/



function f_and($a,$b){

$a=gmp_init(strval($a));

$b=gmp_init(strval($b));

$d=gmp_and($a,$b);

return floatval(gmp_strval($d));

}



function f_or($a,$b){

$a=gmp_init(strval($a));

$b=gmp_init(strval($b));

$d=gmp_or($a,$b);

return floatval(gmp_strval($d));

}



function f_xor($a,$b){

$a=gmp_init(strval($a));

$b=gmp_init(strval($b));

$d=gmp_xor($a,$b);

return floatval(gmp_strval($d));

}



function f_not($a){

$a=gmp_init(strval($a));

$d=gmp_strval($a,2);

$d=str_replace("1","x",$d);

$d=str_replace("0","1",$d);

$d=str_replace("x","0",$d);

$d=gmp_init($d,2);

return floatval(gmp_strval($d,10));

}



function f_dec2bin($a){

$a=gmp_init(strval($a));

return gmp_strval($a,2);

}



function f_bin2dec($a){

$a=gmp_init(strval($a),2);

return floatval(gmp_strval($a,10));

}



function f_ip2dec($a){

$d = 0.0;

$b = explode(".", $a,4);

for ($i = 0; $i < 4; $i++) {

        $d *= 256.0;

        $d += $b[$i];

    };

return $d;

}



function f_dec2ip($a){

    $b=array(0,0,0,0);

    $c = 16777216.0;

    $a += 0.0;

    for ($i = 0; $i < 4; $i++) {

        $k = (int) ($a / $c);

        $a -= $c * $k;

        $b[$i]= $k;

        $c /=256.0;

    };

    $d=join('.', $b);

    return($d);

}



function f_dec2cidr($a){

$a=gmp_init(strval($a));

$d=strlen(str_replace("0","",gmp_strval($a,2)));

return $d;

}



function f_dec2ipall($dNet,$dMask){

  $dWildCard=f_not($dMask);

  $IpAll["Net"]=f_dec2ip($dNet);

  $IpAll["Mask"]=f_dec2ip($dMask);

  $IpAll["WildCard"]=f_dec2ip($dWildCard);

  $IpAll["Cidr"]=f_dec2cidr($dMask);

  $IpAll["Bcast"]=f_dec2ip(f_or($dNet,$dWildCard));

  $IpAll["nIp"]=$dWildCard+1;

  $IpAll["nIpUtil"]=$dWildCard-1;

  if($IpAll["nIp"] > 2){

        $IpAll["IpFrom"]=f_dec2ip($dNet+1);

        $IpAll["IpTo"]=f_dec2ip($dNet+$dWildCard-1);

  }

  else

  {

        $IpAll["IpFrom"]="-";

        $IpAll["IpTo"]="-";

        $IpAll["nIpUtil"]=0;

  }

  return $IpAll;

}



?>



=============================================================

GMP install steps in Mandrake 9.1: 

----------------------------------------------------------

cp -r /usr/src/php-devel/extensions/gmp /tmp/gmp

cd /tmp/gmp

phpize

./configure

make install

echo "extension = gmp.so" > /etc/php/90_gmp.ini



Restart apache web server.

----------------------------------------------------------

gmp.so is in:

/usr/lib/php/extensions/



look in phpinfo, the string:

/etc/php/90_gmp.ini 



Needs these tools:

autoconf

automake

libtool

m4

php430-devel-430-11mdk.rpm

all rpm�s that are envolved to run and compile gmp (*gmp*.rpm)



Some docs about self contained extensions:

/usr/share/doc/php430-devel-430/SELF-CONTAINED-EXTENSIONS

=============================================================

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