57 lines
2.2 KiB
PHP
57 lines
2.2 KiB
PHP
<?php
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class LogicUtils
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{
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public static function extend(string $num, int $base, int $exnd, bool $comp): string
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{
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$fd = (int)(base_convert($num[0], $base, 10)); // get first digit as a number
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$extd = (string)(($comp && ($fd >= ($base / 2))) ? ($base - 1) : 0); // get the extension digit
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return str_pad((string)($num), $exnd, $extd, STR_PAD_LEFT); // extend to the left
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}
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public static function complement(string $num, int $base): string
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{
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// convert to an integer
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$M = (int)(base_convert($num, $base, 10));
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// check if the highest digit is less than the half of the base, if not, add a zero prefix
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$fd = (int)(base_convert($num[0], $base, 10));
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// create the basis for forming the complement
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$H = (string)($base - 1);
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$K_str = (int)(str_repeat($H, strlen($num)));
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if ($fd >= ($base / 2)) { // if one more digit is needed...
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$K_str = $H . $K_str; // prepend with a zero digit
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}
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// convert to integer
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$K = (int)(base_convert($K_str, $base, 10));
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// form the base's complement
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$C = $K - $M + 1;
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// convert to the final base
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return base_convert((string)$C, 10, $base);
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}
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public static function changeRepresentation(int $num, int $base, string $rep, int $digits): string {
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$neg = $num < 0; // store if the value is negative
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$numa_str = (string)(abs($num)); // create the absolute value as a string
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$numa_str = base_convert($numa_str, 10, $base); // convert to specific base
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if ($neg) {
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if ($rep === "s") {
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$numa_str = self::extend($numa_str, $base, $digits, false);
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$numa_str = "-" . $numa_str;
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} else if ($rep === "c") {
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$numa_str = self::complement($numa_str, $base);
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$numa_str = self::extend($numa_str, $base, $digits, true);
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}
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} else {
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$numa_str = self::extend($numa_str, $base, $digits, false);
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if (($rep === "c") && ($numa_str[0] >= ($base / 2))) {
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$numa_str = "0" . $numa_str;
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}
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}
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return $numa_str;
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}
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} |