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<?php |
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/** |
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* Alxarafe. Development of PHP applications in a flash! |
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* Copyright (C) 2018-2020 Alxarafe <[email protected]> |
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*/ |
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namespace Alxarafe\Core\Utils; |
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use Alxarafe\Core\Singletons\Debug; |
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use Alxarafe\Database\Schema; |
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class MathUtils |
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{ |
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/** |
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* Retorna el número de bytes que son necesarios para almacenar un número que |
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* vaya entre $min y $max, considerando si hay o no signo. |
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* |
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* Téngase en cuenta que min y unsigned son casi excluyentes, pero que unsigned |
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* sí que afecta al tamaño máximo positivo. |
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* |
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* Esta función pretende determinar el tipo de entero necesario. Las |
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* inconsistencias (que no son tales), las tendrá que contemplar quién lo invoque. |
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* |
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* @author Rafael San José Tovar <[email protected]> |
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* |
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* @param int $max |
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* @param int $min |
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* @param bool $unsigned |
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* |
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* @return int |
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*/ |
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public static function howManyBytes(int $max, int $min = 0, bool $unsigned = Schema::DEFAULT_INTEGER_UNSIGNED): int |
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{ |
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if ($min > $max) { |
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Debug::message('Se ha invocado a howManyBytes con el mínimo y máximo cambiados'); |
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$tmp = $min; |
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$min = $max; |
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$max = $tmp; |
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} |
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$bits = log($max + 1, 2); |
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if (!$unsigned) { |
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$bits++; |
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} |
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$bytes = ceil($bits / 8); |
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if ($min >= 0) { |
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return $bytes; |
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} |
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$bits = log(abs($min), 2); |
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$bytesForMin = ceil(($bits + 1) / 8); |
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if ($bytesForMin > $bytes) { |
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return $bytesForMin; |
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} |
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return $bytes; |
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} |
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public static function getMinMax(int $size, $unsigned = true): array |
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{ |
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$bits = 8 * (int) $size; |
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$physicalMaxLength = 2 ** $bits; |
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/** |
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* $minDataLength y $maxDataLength contendrán el mínimo y máximo valor que puede contener el campo. |
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*/ |
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$minDataLength = $unsigned ? 0 : -$physicalMaxLength / 2; |
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$maxDataLength = ($unsigned ? $physicalMaxLength : $physicalMaxLength / 2) - 1; |
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return [ |
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'min' => $minDataLength, |
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'max' => $maxDataLength, |
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]; |
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} |
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} |
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rsanjoseo /
alxarafe
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