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BigInteger: refactor randomPrime somewhat

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terrafrost 2013-06-08 11:10:52 -05:00
parent e85f5c7198
commit 043ad01eca
1 changed files with 25 additions and 31 deletions
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54
phpseclib/Math/BigInteger.php
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@ -3116,22 +3116,6 @@ class Math_BigInteger {
*/ */
function randomPrime($min = false, $max = false, $timeout = false) function randomPrime($min = false, $max = false, $timeout = false)
{ {
$compare = $max->compare($min);
if (!$compare) {
return $min;
} else if ($compare < 0) {
// if $min is bigger then $max, swap $min and $max
$temp = $max;
$max = $min;
$min = $temp;
}
// gmp_nextprime() requires PHP 5 >= 5.2.0 per <http://php.net/gmp-nextprime>.
if ( MATH_BIGINTEGER_MODE == MATH_BIGINTEGER_MODE_GMP && function_exists('gmp_nextprime') ) {
// we don't rely on Math_BigInteger::random()'s min / max when gmp_nextprime() is being used since this function
// does its own checks on $max / $min when gmp_nextprime() is used. When gmp_nextprime() is not used, however,
// the same $max / $min checks are not performed.
if ($min === false) { if ($min === false) {
$min = new Math_BigInteger(0); $min = new Math_BigInteger(0);
} }
@ -3140,21 +3124,15 @@ class Math_BigInteger {
$max = new Math_BigInteger(0x7FFFFFFF); $max = new Math_BigInteger(0x7FFFFFFF);
} }
$x = $this->random($min, $max); $compare = $max->compare($min);
$x->value = gmp_nextprime($x->value); if (!$compare) {
return $min->isPrime() ? $min : false;
if ($x->compare($max) <= 0) { } else if ($compare < 0) {
return $x; // if $min is bigger then $max, swap $min and $max
} $temp = $max;
$max = $min;
$x->value = gmp_nextprime($min->value); $min = $temp;
if ($x->compare($max) <= 0) {
return $x;
}
return false;
} }
static $one, $two; static $one, $two;
@ -3166,6 +3144,22 @@ class Math_BigInteger {
$start = time(); $start = time();
$x = $this->random($min, $max); $x = $this->random($min, $max);
// gmp_nextprime() requires PHP 5 >= 5.2.0 per <http://php.net/gmp-nextprime>.
if ( MATH_BIGINTEGER_MODE == MATH_BIGINTEGER_MODE_GMP && function_exists('gmp_nextprime') ) {
$p->value = gmp_nextprime($x->value);
if ($p->compare($max) <= 0) {
return $p;
}
if (!$min->equals($x)) {
$x = $x->subtract($one);
}
return $x->randomPrime($min, $x);
}
if ($x->equals($two)) { if ($x->equals($two)) {
return $x; return $x;
} }