Online PHP editor | refs for E7cb5

<?php /** * Random_* Compatibility Library * for using the new PHP 7 random_* API in PHP 5 projects * * The MIT License (MIT) * * Copyright (c) 2015 Paragon Initiative Enterprises * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal * in the Software without restriction, including without limitation the rights * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell * copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE * SOFTWARE. */ if (!function_exists('random_int')) { /** * Fetch a random integer between $min and $max inclusive * * @param int $min * @param int $max * * @throws Exception * * @return int */ function random_int($min, $max) { /** * Type and input logic checks */ if (!is_int($min)) { throw new Exception( 'random_int(): $min must be an integer' ); } if (!is_int($max)) { throw new Exception( 'random_int(): $max must be an integer' ); } if ($min > $max) { throw new Exception( 'Minimum value must be less than or equal to the maximum value' ); } if ($max === $min) { return $min; } /** * Initialize variables to 0 * * We want to store: * $bytes => the number of random bytes we need * $mask => an integer bitmask (for use with the &) operator * so we can minimize the number of discards */ $attempts = $bits = $bytes = $mask = $valueShift = 0; /** * At this point, $range is a positive number greater than 0. It might * overflow, however, if $max - $min > PHP_INT_MAX. PHP will cast it to * a float and we will lose some precision. */ $range = $max - $min; /** * Test for integer overflow: */ if (!is_int($range)) { /** * Still safely calculate wider ranges. * Provided by @CodesInChaos, @oittaa * * @ref https://gist.github.com/CodesInChaos/03f9ea0b58e8b2b8d435 * * We use ~0 as a mask in this case because it generates all 1s * * @ref https://eval.in/400356 (32-bit) * @ref http://3v4l.org/XX9r5 (64-bit) */ $bytes = PHP_INT_SIZE; $mask = ~0; } else { /** * $bits is effectively ceil(log($range, 2)) without dealing with * type juggling */ while ($range > 0) { if ($bits % 8 === 0) { ++$bytes; } ++$bits; $range >>= 1; $mask = $mask << 1 | 1; } $valueShift = $min; } /** * Now that we have our parameters set up, let's begin generating * random integers until one falls between $min and $max */ do { /** * The rejection probability is at most 0.5, so this corresponds * to a failure probability of 2^-128 for a working RNG */ if ($attempts > 128) { throw new Exception( 'random_int: RNG is broken - too many rejections' ); } /** * Let's grab the necessary number of random bytes */ $randomByteString = mcrypt_create_iv($bytes, MCRYPT_DEV_URANDOM); if ($randomByteString === false) { throw new Exception( 'Random number generator failure' ); } /** * Let's turn $randomByteString into an integer * * This uses bitwise operators (<< and |) to build an integer * out of the values extracted from ord() * * Example: [9F] | [6D] | [32] | [0C] => * 159 + 27904 + 3276800 + 201326592 => * 204631455 */ $val = 0; for ($i = 0; $i < $bytes; ++$i) { $val |= ord($randomByteString[$i]) << ($i * 8); } /** * Apply mask */ $val &= $mask; $val += $valueShift; ++$attempts; /** * If $val overflows to a floating point number, * ... or is larger than $max, * ... or smaller than $int, * then try again. */ } while (!is_int($val) || $val > $max || $val < $min); return (int) $val; } } function random_unique_select($num, array $possible_values) { $sizeof = count($possible_values); if ($num > $sizeof) { throw new InvalidArgumentException('$num is too large'); } $selected = []; for ($i = 0; $i < $num; ++$i) { // Grab a random int [0, ... N - 1] $r = random_int(0, $sizeof - 1); // Copy the selected value into $selected $selected[] = $possible_values[$r]; // Delete it from the range of possible values unset($possible_values[$r]); // N has grown smaller by 1 --$sizeof; // Reset keys; we want this to be zero-indexed. $possible_values = array_values($possible_values); } return $selected; } $results = []; for ($i = 0; $i < 100000; ++$i) { $lottery = json_encode(random_unique_select(6, range(1,29))); if (isset($results[$lottery])) { $results[$lottery]++; } else { $results[$lottery] = 1; } } var_dump($results);

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