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Diffstat (limited to 'oracles/calc.php')
| -rw-r--r-- | oracles/calc.php | 158 |
1 files changed, 158 insertions, 0 deletions
diff --git a/oracles/calc.php b/oracles/calc.php new file mode 100644 index 0000000..4888b95 --- /dev/null +++ b/oracles/calc.php @@ -0,0 +1,158 @@ +<?php +include_once("oracles/base.php"); +class calculator extends oracle { + public $info = [ + "name" => "calculator" + ]; + public function check_query($q) { + // straight numerics should go to that oracle + if (is_numeric($q)) { + return false; + } + // all chars should be number-y or operator-y + $char_whitelist = str_split("1234567890.+-/*^%() "); + foreach (str_split($q) as $char) { + if (!in_array($char, $char_whitelist)) { + return false; + } + } + return true; + } + // a custom parser and calculator because FUCK YUO, libraries are + // gay. + public function generate_response($q) + { + $nums = str_split("1234567890."); + $ops = str_split("+-/*^%;"); + $grouping = str_split("()"); + + $q = str_replace(" ", "", $q); + + // backstop for the parser so it catches the last + // numeric token + $q .= ";"; + + // the following comments refer to this example input: + // 21+9*(3+2^9)+1 + + // 2-length lists of the following patterns: + // ["n" (umeric), <some number>] + // ["o" (perator), "<some operator>"] + // ["g" (roup explicit), <"(" or ")">] + // e.g. [["n", 21], ["o", "+"], ["n", 9], ["o", *], + // ["g", "("], ["n", 3], ["o", "+"], ["n", 2], + // ["o", "^"], ["n", 9], ["g", ")"], ["o", "+"], + // ["n", "1"]] + $tokens = array(); + $dragline = 0; + foreach(str_split($q) as $i=>$char) { + if (in_array($char, $nums)) { + continue; + } + elseif (in_array($char, $ops) || in_array($char, $grouping)) { + // hitting a non-numeric implies everything since the + // last hit has been part of a number + $capture = substr($q, $dragline, $i - $dragline); + // prevent the int cast from creating imaginary + // ["n", 0] tokens + if ($capture != "") { + if (substr_count($capture, ".") > 1) { + return ""; + } + array_push($tokens, ["n", (float)$capture]); + } + // reset to one past the current (non-numeric) char + $dragline = $i + 1; + // the `;' backstop is not a real token and this should + // never be present in the token list + if ($char != ";") { + array_push($tokens, [ + ($char == "(" || $char == ")") ? "g" : "o", + $char + ]); + } + } + else { + return ""; + } + } + + // two operators back to back should fail + for ($i = 1; $i < count($tokens); $i++) { + if ($tokens[$i][0] == "o" && $tokens[$i-1][0] == "o") { + return ""; + } + } + + //strategy: + // traverse to group open (if there is one) + // - return to start with the internals + // traverse to ^, attack token previous and after + // same but for *, then / then + then - + // poppers all teh way down + try { + return [ + substr($q, 0, strlen($q)-1)." = " => $this->executeBlock($tokens)[0][1] + ]; + } + catch (\Throwable $e) { + if (get_class($e) == "DivisionByZeroError") { + return [ + $q." = " => "Division by Zero Error!!" + ]; + } + return ""; + } + } + public function executeBlock($tokens) { + if (count($tokens) >= 2 && $tokens[0][0] == "o" && $tokens[0][1] == "-" && $tokens[1][0] == "n") { + array_splice($tokens, 0, 2, [["n", -1 * (float)$tokens[1][1]]]); + } + if (count($tokens) > 0 && $tokens[0][0] == "o" || $tokens[count($tokens)-1][0] == "o") { + throw new Exception("Error Processing Request", 1); + } + if (in_array(["g", "("], $tokens)) { + $first_open = array_search(["g", "("], $tokens); + $enclosedality = 1; + for ($i = $first_open+1; $i < count($tokens); $i++) { + if ($tokens[$i][0] == "g") { + $enclosedality += ($tokens[$i][1] == "(") ? 1 : -1; + } + if ($enclosedality == 0) { + array_splice($tokens, + $first_open, + $i+1 - $first_open, + $this->executeBlock( + array_slice($tokens, $first_open+1, $i-1 - $first_open) + ) + ); + break; + } + } + } + $operators_in_pemdas_order = [ + "^" => (fn($x, $y) => $x ** $y), + "*" => (fn($x, $y) => $x * $y), + "/" => (fn($x, $y) => $x / $y), + "%" => (fn($x, $y) => $x % $y), + "+" => (fn($x, $y) => $x + $y), + "-" => (fn($x, $y) => $x - $y) + ]; + foreach ($operators_in_pemdas_order as $op=>$func) { + while (in_array(["o", $op], $tokens)) { + for ($i = 0; $i < count($tokens); $i++) { + if ($tokens[$i] == ["o", $op]) { + array_splice( + $tokens, + $i-1, + 3, + [["n", (string)($func((float)$tokens[$i-1][1], (float)$tokens[$i+1][1]))]] + ); + } + } + } + } + return $tokens; + } +} +?>
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