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/trunk/gmp_supplement.inc.php
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<?php
 
/*
* PHP GMP-Supplement implemented using BCMath
* Copyright 2020-2021 Daniel Marschall, ViaThinkSoft
* Version 2021-05-21
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
 
if (function_exists('bcadd')) {
// ----------------- Implementation of GMP functions using BCMath -----------------
 
if (!function_exists('gmp_init') ) {
define('GMP_ROUND_ZERO', 0);
define('GMP_ROUND_PLUSINF', 1);
define('GMP_ROUND_MINUSINF', 2);
define('GMP_MSW_FIRST', 1);
define('GMP_LSW_FIRST', 2);
define('GMP_LITTLE_ENDIAN', 4);
define('GMP_BIG_ENDIAN', 8);
define('GMP_NATIVE_ENDIAN', 16);
define('GMP_VERSION', '6.0.0');
 
// gmp_abs ( GMP $a ) : GMP
// Absolute value
function gmp_abs($a) {
bcscale(0);
if (bccomp($a, "0") == 1) {
return $a;
} else {
return bcmul($a, "-1");
}
}
 
// gmp_add ( GMP $a , GMP $b ) : GMP
// Add numbers
function gmp_add($a, $b) {
bcscale(0);
 
// bcadd ( string $left_operand , string $right_operand [, int $scale = 0 ] ) : string
return bcadd($a, $b);
}
 
// gmp_and ( GMP $a , GMP $b ) : GMP
// Bitwise AND
function gmp_and($a, $b) {
bcscale(0);
// Convert $a and $b to a binary string
$ab = bc_dec2bin($a);
$bb = bc_dec2bin($b);
$length = max(strlen($ab), strlen($bb));
$ab = str_pad($ab, $length, "0", STR_PAD_LEFT);
$bb = str_pad($bb, $length, "0", STR_PAD_LEFT);
 
// Do the bitwise binary operation
$cb = '';
for ($i=0; $i<$length; $i++) {
$cb .= (($ab[$i] == 1) and ($bb[$i] == 1)) ? '1' : '0';
}
 
// Convert back to a decimal number
return bc_bin2dec($cb);
}
 
// gmp_binomial ( mixed $n , int $k ) : GMP
// Calculates binomial coefficient
function gmp_binomial($n, $k) {
bcscale(0);
throw new Exception("gmp_binomial() NOT IMPLEMENTED");
}
 
// gmp_clrbit ( GMP $a , int $index ) : void
// Clear bit
function gmp_clrbit(&$a, $index) {
bcscale(0);
gmp_setbit($a, $index, false);
}
 
// gmp_cmp ( GMP $a , GMP $b ) : int
// Compare numbers
function gmp_cmp($a, $b) {
bcscale(0);
 
// bccomp ( string $left_operand , string $right_operand [, int $scale = 0 ] ) : int
return bccomp($a, $b);
}
 
// gmp_com ( GMP $a ) : GMP
// Calculates one's complement
function gmp_com($a) {
bcscale(0);
// Convert $a and $b to a binary string
$ab = bc_dec2bin($a);
 
// Swap every bit
for ($i=0; $i<strlen($ab); $i++) {
$ab[$i] = ($ab[$i] == '1' ? '0' : '1');
}
 
// Convert back to a decimal number
return bc_bin2dec($ab);
}
 
// gmp_div_q ( GMP $a , GMP $b [, int $round = GMP_ROUND_ZERO ] ) : GMP
// Divide numbers
function gmp_div_q($a, $b, $round = GMP_ROUND_ZERO/*$round not implemented*/) {
bcscale(0);
 
// bcdiv ( string $dividend , string $divisor [, int $scale = 0 ] ) : string
return bcdiv($a, $b);
}
 
// Divide numbers and get quotient and remainder
// gmp_div_qr ( GMP $n , GMP $d [, int $round = GMP_ROUND_ZERO ] ) : array
function gmp_div_qr($n, $d, $round = GMP_ROUND_ZERO/*$round not implemented*/) {
bcscale(0);
return array(
gmp_div_q($n, $d, $round),
gmp_div_r($n, $d, $round)
);
}
 
// Remainder of the division of numbers
// gmp_div_r ( GMP $n , GMP $d [, int $round = GMP_ROUND_ZERO ] ) : GMP
function gmp_div_r($n, $d, $round = GMP_ROUND_ZERO/*$round not implemented*/) {
bcscale(0);
// The remainder operator can be used with negative integers. The rule is:
// - Perform the operation as if both operands were positive.
// - If the left operand is negative, then make the result negative.
// - If the left operand is positive, then make the result positive.
// - Ignore the sign of the right operand in all cases.
$r = bcmod($n, $d);
if (bccomp($n, "0") < 0) $r = bcmul($r, "-1");
return $r;
}
 
// gmp_div ( GMP $a , GMP $b [, int $round = GMP_ROUND_ZERO ] ) : GMP
// Divide numbers
function gmp_div($a, $b, $round = GMP_ROUND_ZERO/*$round not implemented*/) {
bcscale(0);
return gmp_div_q($a, $b, $round); // Alias von gmp_div_q
}
 
// gmp_divexact ( GMP $n , GMP $d ) : GMP
// Exact division of numbers
function gmp_divexact($n, $d) {
bcscale(0);
return bcdiv($n, $d);
}
 
// gmp_export ( GMP $gmpnumber [, int $word_size = 1 [, int $options = GMP_MSW_FIRST | GMP_NATIVE_ENDIAN ]] ) : string
// Export to a binary string
function gmp_export($gmpnumber, $word_size = 1, $options = GMP_MSW_FIRST | GMP_NATIVE_ENDIAN) {
if ($word_size != 1) throw new Exception("Word size != 1 not implemented");
if ($options != GMP_MSW_FIRST | GMP_NATIVE_ENDIAN) throw new Exception("Different options not implemented");
 
bcscale(0);
$gmpnumber = bcmul($gmpnumber,"1"); // normalize
return gmp_init(bin2hex($gmpnumber), 16);
}
 
// gmp_fact ( mixed $a ) : GMP
// Factorial
function gmp_fact($a) {
bcscale(0);
return bcfact($a);
}
 
// gmp_gcd ( GMP $a , GMP $b ) : GMP
// Calculate GCD
function gmp_gcd($a, $b) {
bcscale(0);
return gmp_gcdext($a, $b)['g'];
}
 
// gmp_gcdext ( GMP $a , GMP $b ) : array
// Calculate GCD and multipliers
function gmp_gcdext($a, $b) {
bcscale(0);
 
// Source: https://github.com/phpseclib/phpseclib/blob/master/phpseclib/Math/BigInteger/Engines/BCMath.php#L285
// modified to make it fit here and to be compatible with gmp_gcdext
 
$s = '1';
$t = '0';
$s_ = '0';
$t_ = '1';
 
while (bccomp($b, '0', 0) != 0) {
$q = bcdiv($a, $b, 0);
 
$temp = $a;
$a = $b;
$b = bcsub($temp, bcmul($b, $q, 0), 0);
 
$temp = $s;
$s = $s_;
$s_ = bcsub($temp, bcmul($s, $q, 0), 0);
 
$temp = $t;
$t = $t_;
$t_ = bcsub($temp, bcmul($t, $q, 0), 0);
}
 
return [
'g' => /*$this->normalize*/($a),
's' => /*$this->normalize*/($s),
't' => /*$this->normalize*/($t)
];
}
 
// gmp_hamdist ( GMP $a , GMP $b ) : int
// Hamming distance
function gmp_hamdist($a, $b) {
bcscale(0);
throw new Exception("gmp_hamdist() NOT IMPLEMENTED");
}
 
// gmp_import ( string $data [, int $word_size = 1 [, int $options = GMP_MSW_FIRST | GMP_NATIVE_ENDIAN ]] ) : GMP
// Import from a binary string
function gmp_import($data, $word_size=1, $options=GMP_MSW_FIRST | GMP_NATIVE_ENDIAN) {
bcscale(0);
 
if ($word_size != 1) throw new Exception("Word size != 1 not implemented");
if ($options != GMP_MSW_FIRST | GMP_NATIVE_ENDIAN) throw new Exception("Different options not implemented");
 
return gmp_init(hex2bin(gmp_strval(gmp_init($data), 16)));
}
 
// gmp_init ( mixed $number [, int $base = 0 ] ) : GMP
// Create GMP number
function gmp_init($number, $base=0) {
bcscale(0);
if ($base == 0) {
// If base is 0 (default value), the actual base is determined from the leading characters:
// if the first two characters are 0x or 0X, hexadecimal is assumed,
// otherwise if the first character is "0", octal is assumed,
// otherwise decimal is assumed.
if (strtoupper(substr($number, 0, 2)) == '0X') {
$base = 16;
} else if (strtoupper(substr($number, 0, 1)) == '0') {
$base = 8;
} else {
$base = 10;
}
}
 
if ($base == 10) {
return $number;
} else {
return base_convert_bigint($number, $base, 10);
}
}
 
// gmp_intval ( GMP $gmpnumber ) : int
// Convert GMP number to integer
function gmp_intval($gmpnumber) {
bcscale(0);
return (int)$gmpnumber;
}
 
// gmp_invert ( GMP $a , GMP $b ) : GMP
// Inverse by modulo
function gmp_invert($a, $b) {
bcscale(0);
 
// Source: https://github.com/CityOfZion/neo-php/blob/master/src/Crypto/NumberTheory.php#L246
 
while (bccomp($a, '0')==-1) {
$a=bcadd($b, $a);
}
while (bccomp($b, $a)==-1) {
$a=bcmod($a, $b);
}
$c=$a;
$d=$b;
$uc=1;
$vc=0;
$ud=0;
$vd=1;
while (bccomp($c, '0')!=0) {
$temp1=$c;
$q=bcdiv($d, $c, 0);
$c=bcmod($d, $c);
$d=$temp1;
$temp2=$uc;
$temp3=$vc;
$uc=bcsub($ud, bcmul($q, $uc));
$vc=bcsub($vd, bcmul($q, $vc));
$ud=$temp2;
$vd=$temp3;
}
$result='';
if (bccomp($d, '1')==0) {
if (bccomp($ud, '0')==1) {
$result=$ud;
} else {
$result=bcadd($ud, $b);
}
} else {
throw new ErrorException("ERROR: $a and $b are NOT relatively prime.");
}
return $result;
}
 
// gmp_jacobi ( GMP $a , GMP $p ) : int
// Jacobi symbol
function gmp_jacobi($a, $p) {
bcscale(0);
 
// Source: https://github.com/CityOfZion/neo-php/blob/master/src/Crypto/NumberTheory.php#L136
 
if ($p>=3 && $p%2==1) {
$a = bcmod($a, $p);
if ($a == '0') return '0';
if ($a == '1') return '1';
$a1 = $a;
$e = 0;
while (bcmod($a1, '2') == '0') {
$a1 = bcdiv($a1, '2');
$e = bcadd($e, '1');
}
$s = (bcmod($e, '2')=='0' || bcmod($p, '8')=='1' || bcmod($p, '8')=='7') ? '1' : '-1';
if ($a1 == '1') return $s;
if (bcmod($p, '4')=='3' && bcmod($a1, '4')=='3') $s = -$s;
return bcmul($s, (string)gmp_jacobi(bcmod($p, $a1), $a1));
} else {
return false;
}
}
 
// gmp_kronecker ( mixed $a , mixed $b ) : int
// Kronecker symbol
function gmp_kronecker($a, $b) {
bcscale(0);
throw new Exception("gmp_kronecker() NOT IMPLEMENTED");
}
 
// gmp_lcm ( mixed $a , mixed $b ) : GMP
// Calculate LCM
function gmp_lcm($a, $b) {
bcscale(0);
 
if ((bccomp($a,'0')==0) && (bccomp($b,'0')==0)) {
return '0';
} else {
return gmp_div(gmp_abs(gmp_mul($a,$b)), gmp_gcd($a,$b));
}
}
 
// gmp_legendre ( GMP $a , GMP $p ) : int
// Legendre symbol
function gmp_legendre($a, $p) {
bcscale(0);
throw new Exception("gmp_legendre() NOT IMPLEMENTED");
}
 
// gmp_mod ( GMP $n , GMP $d ) : GMP
// Modulo operation
function gmp_mod($n, $d) {
bcscale(0);
 
// bcmod ( string $dividend , string $divisor [, int $scale = 0 ] ) : string
return bcmod($n, $d);
}
 
// gmp_mul ( GMP $a , GMP $b ) : GMP
// Multiply numbers
function gmp_mul($a, $b) {
bcscale(0);
 
// bcmul ( string $left_operand , string $right_operand [, int $scale = 0 ] ) : string
return bcmul($a, $b);
}
 
// gmp_neg ( GMP $a ) : GMP
// Negate number
function gmp_neg($a) {
bcscale(0);
return bcmul($a, "-1");
}
 
// gmp_nextprime ( int $a ) : GMP
// Find next prime number
function gmp_nextprime($a) {
bcscale(0);
 
// Source: https://github.com/CityOfZion/neo-php/blob/master/src/Crypto/NumberTheory.php#L692
 
if (bccomp($a, '2') == '-1') {
return '2';
}
$result = gmp_or(bcadd($a, '1'), '1');
while (!gmp_prob_prime($result)) {
$result = bcadd($result, '2');
}
return $result;
}
 
// gmp_or ( GMP $a , GMP $b ) : GMP
// Bitwise OR
function gmp_or($a, $b) {
bcscale(0);
// Convert $a and $b to a binary string
$ab = bc_dec2bin($a);
$bb = bc_dec2bin($b);
$length = max(strlen($ab), strlen($bb));
$ab = str_pad($ab, $length, "0", STR_PAD_LEFT);
$bb = str_pad($bb, $length, "0", STR_PAD_LEFT);
 
// Do the bitwise binary operation
$cb = '';
for ($i=0; $i<$length; $i++) {
$cb .= (($ab[$i] == 1) or ($bb[$i] == 1)) ? '1' : '0';
}
 
// Convert back to a decimal number
return bc_bin2dec($cb);
}
 
// gmp_perfect_power ( mixed $a ) : bool
// Perfect power check
function gmp_perfect_power($a) {
bcscale(0);
throw new Exception("gmp_perfect_power() NOT IMPLEMENTED");
}
 
// gmp_perfect_square ( GMP $a ) : bool
// Perfect square check
function gmp_perfect_square($a) {
bcscale(0);
throw new Exception("gmp_perfect_square() NOT IMPLEMENTED");
}
 
// gmp_popcount ( GMP $a ) : int
// Population count
function gmp_popcount($a) {
bcscale(0);
$ab = bc_dec2bin($a);
return substr_count($ab, '1');
}
 
// gmp_pow ( GMP $base , int $exp ) : GMP
// Raise number into power
function gmp_pow($base, $exp) {
bcscale(0);
 
// bcpow ( string $base , string $exponent [, int $scale = 0 ] ) : string
return bcpow($base, $exp);
}
 
// gmp_powm ( GMP $base , GMP $exp , GMP $mod ) : GMP
// Raise number into power with modulo
function gmp_powm($base, $exp, $mod) {
bcscale(0);
 
// bcpowmod ( string $base , string $exponent , string $modulus [, int $scale = 0 ] ) : string
return bcpowmod($base, $exp, $mod);
}
 
// gmp_prob_prime ( GMP $a [, int $reps = 10 ] ) : int
// Check if number is "probably prime"
function gmp_prob_prime($a, $reps=10) {
bcscale(0);
 
// Source: https://github.com/CityOfZion/neo-php/blob/master/src/Crypto/NumberTheory.php#L655
 
$t = 40;
$k = 0;
$m = bcsub($reps, '1');
while (bcmod($m, '2') == '0') {
$k = bcadd($k, '1');
$m = bcdiv($m, '2');
}
for ($i=0; $i<$t; $i++) {
$a = bcrand('1', bcsub($reps, '1'));
if ($m < 0) {
return new ErrorException("Negative exponents ($m) not allowed");
} else {
$b0 = bcpowmod($a, $m, $reps);
}
if ($b0!=1 && $b0!=bcsub($reps, '1')) {
$j = 1;
while ($j<=$k-1 && $b0!=bcsub($reps, '1')) {
$b0 = bcpowmod($b0, '2', $reps);
if ($b0 == 1) {
return false;
}
$j++;
}
if ($b0 != bcsub($reps, '1')) {
return false;
}
}
}
return true;
}
 
// gmp_random_bits ( int $bits ) : GMP
// Random number
function gmp_random_bits($bits) {
bcscale(0);
$min = 0;
$max = bcsub(bcpow('2', $bits), '1');
return bcrand($min, $max);
}
 
// gmp_random_range ( GMP $min , GMP $max ) : GMP
// Random number
function gmp_random_range($min, $max) {
bcscale(0);
return bcrand($min, $max);
}
 
// gmp_random_seed ( mixed $seed ) : void
// Sets the RNG seed
function gmp_random_seed($seed) {
bcscale(0);
bcrand_seed($seed);
}
 
// gmp_random ([ int $limiter = 20 ] ) : GMP
// Random number (deprecated)
function gmp_random($limiter=20) {
bcscale(0);
throw new Exception("gmp_random() is deprecated! Please use gmp_random_bits() or gmp_random_range() instead.");
}
 
// gmp_root ( GMP $a , int $nth ) : GMP
// Take the integer part of nth root
function gmp_root($a, $nth) {
bcscale(0);
throw new Exception("gmp_root() NOT IMPLEMENTED");
}
 
// gmp_rootrem ( GMP $a , int $nth ) : array
// Take the integer part and remainder of nth root
function gmp_rootrem($a, $nth) {
bcscale(0);
throw new Exception("gmp_rootrem() NOT IMPLEMENTED");
}
 
// gmp_scan0 ( GMP $a , int $start ) : int
// Scan for 0
function gmp_scan0($a, $start) {
bcscale(0);
 
$ab = bc_dec2bin($a);
 
if ($start < 0) throw new Exception("Starting index must be greater than or equal to zero");
if ($start >= strlen($ab)) return $start;
 
for ($i=$start; $i<strlen($ab); $i++) {
if ($ab[strlen($ab)-1-$i] == '0') {
return $i;
}
}
 
return false;
}
 
// gmp_scan1 ( GMP $a , int $start ) : int
// Scan for 1
function gmp_scan1($a, $start) {
bcscale(0);
 
$ab = bc_dec2bin($a);
 
if ($start < 0) throw new Exception("Starting index must be greater than or equal to zero");
if ($start >= strlen($ab)) return -1;
 
for ($i=$start; $i<strlen($ab); $i++) {
if ($ab[strlen($ab)-1-$i] == '1') {
return $i;
}
}
 
return false;
}
 
// gmp_setbit ( GMP $a , int $index [, bool $bit_on = TRUE ] ) : void
// Set bit
function gmp_setbit(&$a, $index, $bit_on=TRUE) {
bcscale(0);
$ab = bc_dec2bin($a);
 
if ($index < 0) throw new Exception("Invalid index");
if ($index >= strlen($ab)) {
$ab = str_pad($ab, $index+1, '0', STR_PAD_LEFT);
}
 
$ab[strlen($ab)-1-$index] = $bit_on ? '1' : '0';
 
$a = bc_bin2dec($ab);
}
 
// gmp_sign ( GMP $a ) : int
// Sign of number
function gmp_sign($a) {
bcscale(0);
return bccomp($a, "0");
}
 
// gmp_sqrt ( GMP $a ) : GMP
// Calculate square root
function gmp_sqrt($a) {
bcscale(0);
 
// bcsqrt ( string $operand [, int $scale = 0 ] ) : string
return bcsqrt($a);
}
 
// gmp_sqrtrem ( GMP $a ) : array
// Square root with remainder
function gmp_sqrtrem($a) {
bcscale(0);
throw new Exception("gmp_sqrtrem() NOT IMPLEMENTED");
}
 
// gmp_strval ( GMP $gmpnumber [, int $base = 10 ] ) : string
// Convert GMP number to string
function gmp_strval($gmpnumber, $base=10) {
bcscale(0);
if ($base == 10) {
return $gmpnumber;
} else {
return base_convert_bigint($gmpnumber, 10, $base);
}
}
 
// gmp_sub ( GMP $a , GMP $b ) : GMP
// Subtract numbers
function gmp_sub($a, $b) {
bcscale(0);
 
// bcsub ( string $left_operand , string $right_operand [, int $scale = 0 ] ) : string
return bcsub($a, $b);
}
 
// gmp_testbit ( GMP $a , int $index ) : bool
// Tests if a bit is set
function gmp_testbit($a, $index) {
bcscale(0);
$ab = bc_dec2bin($a);
 
if ($index < 0) throw new Exception("Invalid index");
if ($index >= strlen($ab)) return ('0' == '1');
 
return $ab[strlen($ab)-1-$index] == '1';
}
 
// gmp_xor ( GMP $a , GMP $b ) : GMP
// Bitwise XOR
function gmp_xor($a, $b) {
bcscale(0);
// Convert $a and $b to a binary string
$ab = bc_dec2bin($a);
$bb = bc_dec2bin($b);
$length = max(strlen($ab), strlen($bb));
$ab = str_pad($ab, $length, "0", STR_PAD_LEFT);
$bb = str_pad($bb, $length, "0", STR_PAD_LEFT);
 
// Do the bitwise binary operation
$cb = '';
for ($i=0; $i<$length; $i++) {
$cb .= (($ab[$i] == 1) xor ($bb[$i] == 1)) ? '1' : '0';
}
 
// Convert back to a decimal number
return bc_bin2dec($cb);
}
}
 
// ----------------- Helper functions -----------------
 
function base_convert_bigint($numstring, $frombase, $tobase) {
$frombase_str = '';
for ($i=0; $i<$frombase; $i++) {
$frombase_str .= strtoupper(base_convert((string)$i, 10, 36));
}
 
$tobase_str = '';
for ($i=0; $i<$tobase; $i++) {
$tobase_str .= strtoupper(base_convert((string)$i, 10, 36));
}
 
$length = strlen($numstring);
$result = '';
$number = array();
for ($i = 0; $i < $length; $i++) {
$number[$i] = stripos($frombase_str, $numstring[$i]);
}
do { // Loop until whole number is converted
$divide = 0;
$newlen = 0;
for ($i = 0; $i < $length; $i++) { // Perform division manually (which is why this works with big numbers)
$divide = $divide * $frombase + $number[$i];
if ($divide >= $tobase) {
$number[$newlen++] = (int)($divide / $tobase);
$divide = $divide % $tobase;
} else if ($newlen > 0) {
$number[$newlen++] = 0;
}
}
$length = $newlen;
$result = $tobase_str[$divide] . $result; // Divide is basically $numstring % $tobase (i.e. the new character)
}
while ($newlen != 0);
 
return $result;
}
 
function bc_dec2bin($decimal_i) {
// https://www.exploringbinary.com/base-conversion-in-php-using-bcmath/
 
bcscale(0);
 
$binary_i = '';
do {
$binary_i = bcmod($decimal_i,'2') . $binary_i;
$decimal_i = bcdiv($decimal_i,'2');
} while (bccomp($decimal_i,'0'));
 
return $binary_i;
}
 
function bc_bin2dec($binary_i) {
// https://www.exploringbinary.com/base-conversion-in-php-using-bcmath/
 
bcscale(0);
 
$decimal_i = '0';
for ($i = 0; $i < strlen($binary_i); $i++) {
$decimal_i = bcmul($decimal_i,'2');
$decimal_i = bcadd($decimal_i,$binary_i[$i]);
}
 
return $decimal_i;
}
 
// ----------------- New functions -----------------
 
// Newly added: gmp_not / bcnot
function bcnot($a) {
bcscale(0);
// Convert $a to a binary string
$ab = bc_dec2bin($a);
$length = strlen($ab);
 
// Do the bitwise binary operation
$cb = '';
for ($i=0; $i<$length; $i++) {
$cb .= ($ab[$i] == 1) ? '0' : '1';
}
 
// Convert back to a decimal number
return bc_bin2dec($cb);
}
function gmp_not($a) {
bcscale(0);
return bcnot($a);
}
 
// Newly added: bcshiftl / gmp_shiftl
function bcshiftl($num, $bits) {
bcscale(0);
return bcmul($num, bcpow('2', $bits));
}
function gmp_shiftl($num, $bits) {
bcscale(0);
return bcshiftl($num, $bits);
}
 
// Newly added: bcshiftr / gmp_shiftr
function bcshiftr($num, $bits) {
bcscale(0);
return bcdiv($num, bcpow('2', $bits));
}
function gmp_shiftr($num, $bits) {
bcscale(0);
return bcshiftr($num, $bits);
}
 
// Newly added: bcfact (used by gmp_fact)
function bcfact($a) {
bcscale(0);
 
// Source: https://www.php.net/manual/de/book.bc.php#116510
 
if (!filter_var($a, FILTER_VALIDATE_INT) || $a <= 0) {
throw new InvalidArgumentException(sprintf('Argument must be natural number, "%s" given.', $a));
}
 
for ($result = '1'; $a > 0; $a--) {
$result = bcmul($result, $a);
}
 
return $result;
}
 
// Newly added (used by gmp_prob_prime, gmp_random_range and gmp_random_bits)
function bcrand($min, $max = false) {
bcscale(0);
// Source: https://github.com/CityOfZion/neo-php/blob/master/src/Crypto/BCMathUtils.php#L7
// Fixed: https://github.com/CityOfZion/neo-php/issues/16
if (!$max) {
$max = $min;
$min = 0;
}
return bcadd(bcmul(bcdiv((string)mt_rand(), (string)mt_getrandmax(), strlen($max)), bcsub(bcadd($max, '1'), $min)), $min);
}
 
// Newly added (used by gmp_random_seed)
function bcrand_seed($seed) {
bcscale(0);
mt_srand($seed);
}
}