MediaWiki 1.30.2

[autoinstallsdev/mediawiki.git] / vendor / wikimedia / base-convert / src / Functions.php

diff --git a/vendor/wikimedia/base-convert/src/Functions.php b/vendor/wikimedia/base-convert/src/Functions.php
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+<?php
+/**
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ * http://www.gnu.org/copyleft/gpl.html
+ *
+ * @file
+ */
+
+namespace Wikimedia;
+
+/**
+ * Convert an arbitrarily-long string from one numeric base to
+ * another, optionally zero-padding to a minimum column width.
+ *
+ * Supports base 2 through 36; digit values 10-36 are represented
+ * as lowercase letters a-z. Input is case-insensitive.
+ *
+ * @param string $input Input number
+ * @param int $sourceBase Base of the input number
+ * @param int $destBase Desired base of the output
+ * @param int $pad Minimum number of digits in the output (pad with zeroes)
+ * @param bool $lowercase Whether to output in lowercase or uppercase
+ * @param string $engine Either "gmp", "bcmath", or "php"
+ * @return string|bool The output number as a string, or false on error
+ */
+function base_convert( $input, $sourceBase, $destBase, $pad = 1,
+                                               $lowercase = true, $engine = 'auto'
+) {
+       $input = (string)$input;
+       if (
+               $sourceBase < 2 ||
+               $sourceBase > 36 ||
+               $destBase < 2 ||
+               $destBase > 36 ||
+               $sourceBase != (int)$sourceBase ||
+               $destBase != (int)$destBase ||
+               $pad != (int)$pad ||
+               !preg_match(
+                       "/^[" . substr( '0123456789abcdefghijklmnopqrstuvwxyz', 0, $sourceBase ) . "]+$/i",
+                       $input
+               )
+       ) {
+               return false;
+       }
+
+       static $baseChars = array(
+               10 => 'a', 11 => 'b', 12 => 'c', 13 => 'd', 14 => 'e', 15 => 'f',
+               16 => 'g', 17 => 'h', 18 => 'i', 19 => 'j', 20 => 'k', 21 => 'l',
+               22 => 'm', 23 => 'n', 24 => 'o', 25 => 'p', 26 => 'q', 27 => 'r',
+               28 => 's', 29 => 't', 30 => 'u', 31 => 'v', 32 => 'w', 33 => 'x',
+               34 => 'y', 35 => 'z',
+
+               '0' => 0, '1' => 1, '2' => 2, '3' => 3, '4' => 4, '5' => 5,
+               '6' => 6, '7' => 7, '8' => 8, '9' => 9, 'a' => 10, 'b' => 11,
+               'c' => 12, 'd' => 13, 'e' => 14, 'f' => 15, 'g' => 16, 'h' => 17,
+               'i' => 18, 'j' => 19, 'k' => 20, 'l' => 21, 'm' => 22, 'n' => 23,
+               'o' => 24, 'p' => 25, 'q' => 26, 'r' => 27, 's' => 28, 't' => 29,
+               'u' => 30, 'v' => 31, 'w' => 32, 'x' => 33, 'y' => 34, 'z' => 35
+       );
+
+       if ( extension_loaded( 'gmp' ) && ( $engine == 'auto' || $engine == 'gmp' ) ) {
+               // Removing leading zeros works around broken base detection code in
+               // some PHP versions (see <https://bugs.php.net/bug.php?id=50175> and
+               // <https://bugs.php.net/bug.php?id=55398>).
+               $result = gmp_strval( gmp_init( ltrim( $input, '0' ) ?: '0', $sourceBase ), $destBase );
+       } elseif ( extension_loaded( 'bcmath' ) && ( $engine == 'auto' || $engine == 'bcmath' ) ) {
+               $decimal = '0';
+               foreach ( str_split( strtolower( $input ) ) as $char ) {
+                       $decimal = bcmul( $decimal, $sourceBase );
+                       $decimal = bcadd( $decimal, $baseChars[$char] );
+               }
+
+               // @codingStandardsIgnoreStart Generic.CodeAnalysis.ForLoopWithTestFunctionCall.NotAllowed
+               for ( $result = ''; bccomp( $decimal, 0 ); $decimal = bcdiv( $decimal, $destBase, 0 ) ) {
+                       $result .= $baseChars[bcmod( $decimal, $destBase )];
+               }
+               // @codingStandardsIgnoreEnd
+
+               $result = strrev( $result );
+       } else {
+               $inDigits = array();
+               foreach ( str_split( strtolower( $input ) ) as $char ) {
+                       $inDigits[] = $baseChars[$char];
+               }
+
+               // Iterate over the input, modulo-ing out an output digit
+               // at a time until input is gone.
+               $result = '';
+               while ( $inDigits ) {
+                       $work = 0;
+                       $workDigits = array();
+
+                       // Long division...
+                       foreach ( $inDigits as $digit ) {
+                               $work *= $sourceBase;
+                               $work += $digit;
+
+                               if ( $workDigits || $work >= $destBase ) {
+                                       $workDigits[] = (int)( $work / $destBase );
+                               }
+                               $work %= $destBase;
+                       }
+
+                       // All that division leaves us with a remainder,
+                       // which is conveniently our next output digit.
+                       $result .= $baseChars[$work];
+
+                       // And we continue!
+                       $inDigits = $workDigits;
+               }
+
+               $result = strrev( $result );
+       }
+
+       if ( !$lowercase ) {
+               $result = strtoupper( $result );
+       }
+
+       return str_pad( $result, $pad, '0', STR_PAD_LEFT );
+}