diff --git a/htdocs/core/class/evalmath.class.php b/htdocs/core/class/evalmath.class.php index 536ecf2f271..511fe6b504c 100644 --- a/htdocs/core/class/evalmath.class.php +++ b/htdocs/core/class/evalmath.class.php @@ -1,4 +1,5 @@ evaluate('2+2'); - * // supports: order of operation; parentheses; negation; built-in functions - * $result = $m->evaluate('-8(5/2)^2*(1-sqrt(4))-8'); - * // create your own variables - * $m->evaluate('a = e^(ln(pi))'); - * // or functions - * $m->evaluate('f(x,y) = x^2 + y^2 - 2x*y + 1'); - * // and then use them - * $result = $m->evaluate('3*f(42,a)'); + * include('evalmath.class.php'); + * $m = new EvalMath; + * // basic evaluation: + * $result = $m->evaluate('2+2'); + * // supports: order of operation; parentheses; negation; built-in functions + * $result = $m->evaluate('-8(5/2)^2*(1-sqrt(4))-8'); + * // create your own variables + * $m->evaluate('a = e^(ln(pi))'); + * // or functions + * $m->evaluate('f(x,y) = x^2 + y^2 - 2x*y + 1'); + * // and then use them + * $result = $m->evaluate('3*f(42,a)'); * - * DESCRIPTION - * Use the EvalMath class when you want to evaluate mathematical expressions - * from untrusted sources. You can define your own variables and functions, - * which are stored in the object. Try it, it's fun! + * DESCRIPTION + * Use the EvalMath class when you want to evaluate mathematical expressions + * from untrusted sources. You can define your own variables and functions, + * which are stored in the object. Try it, it's fun! * - * METHODS - * $m->evalute($expr) - * Evaluates the expression and returns the result. If an error occurs, - * prints a warning and returns false. If $expr is a function assignment, - * returns true on success. + * METHODS + * $m->evalute($expr) + * Evaluates the expression and returns the result. If an error occurs, + * prints a warning and returns false. If $expr is a function assignment, + * returns true on success. * - * $m->e($expr) - * A synonym for $m->evaluate(). + * $m->e($expr) + * A synonym for $m->evaluate(). * - * $m->vars() - * Returns an associative array of all user-defined variables and values. + * $m->vars() + * Returns an associative array of all user-defined variables and values. * - * $m->funcs() - * Returns an array of all user-defined functions. + * $m->funcs() + * Returns an array of all user-defined functions. * - * PARAMETERS - * $m->suppress_errors - * Set to true to turn off warnings when evaluating expressions + * PARAMETERS + * $m->suppress_errors + * Set to true to turn off warnings when evaluating expressions * - * $m->last_error - * If the last evaluation failed, contains a string describing the error. - * (Useful when suppress_errors is on). + * $m->last_error + * If the last evaluation failed, contains a string describing the error. + * (Useful when suppress_errors is on). * - * $m->last_error_code - * If the last evaluation failed, 2 element array with numeric code and extra info + * $m->last_error_code + * If the last evaluation failed, 2 element array with numeric code and extra info * - * AUTHOR INFORMATION - * Copyright 2005, Miles Kaufmann. + * AUTHOR INFORMATION + * Copyright 2005, Miles Kaufmann. * - * LICENSE - * Redistribution and use in source and binary forms, with or without - * modification, are permitted provided that the following conditions are - * met: + * LICENSE + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are + * met: * - * 1 Redistributions of source code must retain the above copyright - * notice, this list of conditions and the following disclaimer. - * 2. Redistributions in binary form must reproduce the above copyright - * notice, this list of conditions and the following disclaimer in the - * documentation and/or other materials provided with the distribution. - * 3. The name of the author may not be used to endorse or promote - * products derived from this software without specific prior written - * permission. + * 1 Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. The name of the author may not be used to endorse or promote + * products derived from this software without specific prior written + * permission. * - * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR - * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED - * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE - * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, - * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES - * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR - * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) - * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, - * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN - * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE - * POSSIBILITY OF SUCH DAMAGE. + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR + * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED + * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE + * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, + * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES + * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR + * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, + * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN + * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. */ /** - * \file core/class/evalmath.class.php - * \ingroup core - * \brief This file for Math evaluation + * \file core/class/evalmath.class.php + * \ingroup core + * \brief This file for Math evaluation */ - /** * Class EvalMath */ class EvalMath { - public $suppress_errors = false; - public $last_error = null; - public $last_error_code = null; - public $v = array('e'=>2.71,'pi'=>3.14159); // variables (and constants) - public $f = array(); // user-defined functions - public $vb = array('e', 'pi'); // constants - public $fb = array( // built-in functions - 'sin','sinh','arcsin','asin','arcsinh','asinh', - 'cos','cosh','arccos','acos','arccosh','acosh', - 'tan','tanh','arctan','atan','arctanh','atanh', - 'sqrt','abs','ln','log','intval'); + public $suppress_errors = false; - /** - * Constructor - */ - function __construct() { - // make the variables a little more accurate - $this->v['pi'] = pi(); - $this->v['e'] = exp(1); - } + public $last_error = null; - /** - * Evaluate - * - * @param string $expr String - * @return boolean|number|NULL|mixed Result - */ - function e($expr) { - return $this->evaluate($expr); - } + public $last_error_code = null; - /** - * Evaluate - * - * @param string $expr String - * @return boolean|number|NULL|mixed Result - */ - function evaluate($expr) { - $this->last_error = null; - $this->last_error_code = null; - $expr = trim($expr); - if (substr($expr, -1, 1) == ';') $expr = substr($expr, 0, strlen($expr)-1); // strip semicolons at the end - //=============== - // is it a variable assignment? - if (preg_match('/^\s*([a-z]\w*)\s*=\s*(.+)$/', $expr, $matches)) { - if (in_array($matches[1], $this->vb)) { // make sure we're not assigning to a constant - return $this->trigger(1, "cannot assign to constant '$matches[1]'", $matches[1]); - } - if (($tmp = $this->pfx($this->nfx($matches[2]))) === false) return false; // get the result and make sure it's good - $this->v[$matches[1]] = $tmp; // if so, stick it in the variable array - return $this->v[$matches[1]]; // and return the resulting value - //=============== - // is it a function assignment? - } elseif (preg_match('/^\s*([a-z]\w*)\s*\(\s*([a-z]\w*(?:\s*,\s*[a-z]\w*)*)\s*\)\s*=\s*(.+)$/', $expr, $matches)) { - $fnn = $matches[1]; // get the function name - if (in_array($matches[1], $this->fb)) { // make sure it isn't built in - return $this->trigger(2, "cannot redefine built-in function '$matches[1]()'", $matches[1]); - } - $args = explode(",", preg_replace("/\s+/", "", $matches[2])); // get the arguments - if (($stack = $this->nfx($matches[3])) === false) return false; // see if it can be converted to postfix - $nbstack = count($stack); - for ($i = 0; $i < $nbstack; $i++) { // freeze the state of the non-argument variables - $token = $stack[$i]; - if (preg_match('/^[a-z]\w*$/', $token) and !in_array($token, $args)) { - if (array_key_exists($token, $this->v)) { - $stack[$i] = $this->v[$token]; - } else { - return $this->trigger(3, "undefined variable '$token' in function definition", $token); - } - } - } - $this->f[$fnn] = array('args'=>$args, 'func'=>$stack); - return true; - //=============== - } else { - return $this->pfx($this->nfx($expr)); // straight up evaluation, woo - } - } + public $v = array('e' => 2.71,'pi' => 3.14159); - /** - * vars - * - * @return string Output - */ - function vars() { - $output = $this->v; - unset($output['pi']); - unset($output['e']); - return $output; - } + // variables (and constants) + public $f = array(); - /** - * vars - * - * @return string Output - */ - function funcs() { - $output = array(); - foreach ($this->f as $fnn=>$dat) - $output[] = $fnn . '(' . implode(',', $dat['args']) . ')'; - return $output; - } + // user-defined functions + public $vb = array('e','pi'); + // constants + public $fb = array( // built-in functions + 'sin','sinh','arcsin','asin','arcsinh','asinh','cos','cosh','arccos','acos','arccosh','acosh','tan','tanh','arctan','atan','arctanh','atanh','sqrt','abs','ln','log','intval'); - //===================== HERE BE INTERNAL METHODS ====================\\ + /** + * Constructor + */ + public function __construct() + { + // make the variables a little more accurate + $this->v['pi'] = pi(); + $this->v['e'] = exp(1); + } - /** - * Convert infix to postfix notation - * - * @param string $expr Expression - * @return string Output - */ - function nfx($expr) { + /** + * Evaluate + * + * @param string $expr + * String + * @return boolean|number|NULL|mixed Result + */ + function e($expr) + { + return $this->evaluate($expr); + } - $index = 0; - $stack = new EvalMathStack(); - $output = array(); // postfix form of expression, to be passed to pfx() - $expr = trim(strtolower($expr)); + /** + * Evaluate + * + * @param string $expr + * String + * @return boolean|number|NULL|mixed Result + */ + function evaluate($expr) + { + $this->last_error = null; + $this->last_error_code = null; + $expr = trim($expr); + if (substr($expr, - 1, 1) == ';') + $expr = substr($expr, 0, strlen($expr) - 1); // strip semicolons at the end + // =============== + // is it a variable assignment? + $matches = array(); + if (preg_match('/^\s*([a-z]\w*)\s*=\s*(.+)$/', $expr, $matches)) { + if (in_array($matches[1], $this->vb)) { // make sure we're not assigning to a constant + return $this->trigger(1, "cannot assign to constant '$matches[1]'", $matches[1]); + } + if (($tmp = $this->pfx($this->nfx($matches[2]))) === false) + return false; // get the result and make sure it's good + $this->v[$matches[1]] = $tmp; // if so, stick it in the variable array + return $this->v[$matches[1]]; // and return the resulting value + // =============== + // is it a function assignment? + } elseif (preg_match('/^\s*([a-z]\w*)\s*\(\s*([a-z]\w*(?:\s*,\s*[a-z]\w*)*)\s*\)\s*=\s*(.+)$/', $expr, $matches)) { + $fnn = $matches[1]; // get the function name + if (in_array($matches[1], $this->fb)) { // make sure it isn't built in + return $this->trigger(2, "cannot redefine built-in function '$matches[1]()'", $matches[1]); + } + $args = explode(",", preg_replace("/\s+/", "", $matches[2])); // get the arguments + if (($stack = $this->nfx($matches[3])) === false) + return false; // see if it can be converted to postfix + $nbstack = count($stack); + for ($i = 0; $i < $nbstack; $i ++) { // freeze the state of the non-argument variables + $token = $stack[$i]; + if (preg_match('/^[a-z]\w*$/', $token) and ! in_array($token, $args)) { + if (array_key_exists($token, $this->v)) { + $stack[$i] = $this->v[$token]; + } else { + return $this->trigger(3, "undefined variable '$token' in function definition", $token); + } + } + } + $this->f[$fnn] = array('args' => $args,'func' => $stack); + return true; + // =============== + } else { + return $this->pfx($this->nfx($expr)); // straight up evaluation, woo + } + } - $ops = array('+', '-', '*', '/', '^', '_'); - $ops_r = array('+'=>0,'-'=>0,'*'=>0,'/'=>0,'^'=>1); // right-associative operator? - $ops_p = array('+'=>0,'-'=>0,'*'=>1,'/'=>1,'_'=>1,'^'=>2); // operator precedence + /** + * vars + * + * @return string Output + */ + function vars() + { + $output = $this->v; + unset($output['pi']); + unset($output['e']); + return $output; + } - $expecting_op = false; // we use this in syntax-checking the expression - // and determining when a - is a negation + /** + * vars + * + * @return string Output + */ + function funcs() + { + $output = array(); + foreach ($this->f as $fnn => $dat) + $output[] = $fnn . '(' . implode(',', $dat['args']) . ')'; + return $output; + } - if (preg_match("/[^\w\s+*^\/()\.,-]/", $expr, $matches)) { // make sure the characters are all good - return $this->trigger(4, "illegal character '{$matches[0]}'", $matches[0]); - } + // ===================== HERE BE INTERNAL METHODS ====================\\ - while(1) { // 1 Infinite Loop ;) - $op = substr($expr, $index, 1); // get the first character at the current index - // find out if we're currently at the beginning of a number/variable/function/parenthesis/operand - $ex = preg_match('/^([a-z]\w*\(?|\d+(?:\.\d*)?|\.\d+|\()/', substr($expr, $index), $match); - //=============== - if ($op == '-' and !$expecting_op) { // is it a negation instead of a minus? - $stack->push('_'); // put a negation on the stack - $index++; - } elseif ($op == '_') { // we have to explicitly deny this, because it's legal on the stack - return $this->trigger(4, "illegal character '_'", "_"); // but not in the input expression - //=============== - } elseif ((in_array($op, $ops) or $ex) and $expecting_op) { // are we putting an operator on the stack? - if ($ex) { // are we expecting an operator but have a number/variable/function/opening parethesis? - $op = '*'; $index--; // it's an implicit multiplication - } - // heart of the algorithm: - while($stack->count > 0 and ($o2 = $stack->last()) and in_array($o2, $ops) and ($ops_r[$op] ? $ops_p[$op] < $ops_p[$o2] : $ops_p[$op] <= $ops_p[$o2])) { - $output[] = $stack->pop(); // pop stuff off the stack into the output - } - // many thanks: http://en.wikipedia.org/wiki/Reverse_Polish_notation#The_algorithm_in_detail - $stack->push($op); // finally put OUR operator onto the stack - $index++; - $expecting_op = false; - //=============== - } elseif ($op == ')' and $expecting_op) { // ready to close a parenthesis? - while (($o2 = $stack->pop()) != '(') { // pop off the stack back to the last ( - if (is_null($o2)) return $this->trigger(5, "unexpected ')'", ")"); - else $output[] = $o2; - } - if (preg_match("/^([a-z]\w*)\($/", $stack->last(2), $matches)) { // did we just close a function? - $fnn = $matches[1]; // get the function name - $arg_count = $stack->pop(); // see how many arguments there were (cleverly stored on the stack, thank you) - $output[] = $stack->pop(); // pop the function and push onto the output - if (in_array($fnn, $this->fb)) { // check the argument count - if($arg_count > 1) - return $this->trigger(6, "wrong number of arguments ($arg_count given, 1 expected)", array($arg_count, 1)); - } elseif (array_key_exists($fnn, $this->f)) { - if ($arg_count != count($this->f[$fnn]['args'])) - return $this->trigger(6, "wrong number of arguments ($arg_count given, " . count($this->f[$fnn]['args']) . " expected)", array($arg_count, count($this->f[$fnn]['args']))); - } else { // did we somehow push a non-function on the stack? this should never happen - return $this->trigger(7, "internal error"); - } - } - $index++; - //=============== - } elseif ($op == ',' and $expecting_op) { // did we just finish a function argument? - while (($o2 = $stack->pop()) != '(') { - if (is_null($o2)) return $this->trigger(5, "unexpected ','", ","); // oops, never had a ( - else $output[] = $o2; // pop the argument expression stuff and push onto the output - } - // make sure there was a function - if (!preg_match("/^([a-z]\w*)\($/", $stack->last(2), $matches)) - return $this->trigger(5, "unexpected ','", ","); - $stack->push($stack->pop()+1); // increment the argument count - $stack->push('('); // put the ( back on, we'll need to pop back to it again - $index++; - $expecting_op = false; - //=============== - } elseif ($op == '(' and !$expecting_op) { - $stack->push('('); // that was easy - $index++; - $allow_neg = true; - //=============== - } elseif ($ex and !$expecting_op) { // do we now have a function/variable/number? - $expecting_op = true; - $val = $match[1]; - if (preg_match("/^([a-z]\w*)\($/", $val, $matches)) { // may be func, or variable w/ implicit multiplication against parentheses... - if (in_array($matches[1], $this->fb) or array_key_exists($matches[1], $this->f)) { // it's a func - $stack->push($val); - $stack->push(1); - $stack->push('('); - $expecting_op = false; - } else { // it's a var w/ implicit multiplication - $val = $matches[1]; - $output[] = $val; - } - } else { // it's a plain old var or num - $output[] = $val; - } - $index += strlen($val); - //=============== - } elseif ($op == ')') { // miscellaneous error checking - return $this->trigger(5, "unexpected ')'", ")"); - } elseif (in_array($op, $ops) and !$expecting_op) { - return $this->trigger(8, "unexpected operator '$op'", $op); - } else { // I don't even want to know what you did to get here - return $this->trigger(9, "an unexpected error occured"); - } - if ($index == strlen($expr)) { - if (in_array($op, $ops)) { // did we end with an operator? bad. - return $this->trigger(10, "operator '$op' lacks operand", $op); - } else { - break; - } - } - while (substr($expr, $index, 1) == ' ') { // step the index past whitespace (pretty much turns whitespace - $index++; // into implicit multiplication if no operator is there) - } + /** + * Convert infix to postfix notation + * + * @param string $expr + * Expression + * @return string Output + */ + function nfx($expr) + { + $index = 0; + $stack = new EvalMathStack(); + $output = array(); // postfix form of expression, to be passed to pfx() + $expr = trim(strtolower($expr)); - } - while (!is_null($op = $stack->pop())) { // pop everything off the stack and push onto output - if ($op == '(') return $this->trigger(11, "expecting ')'", ")"); // if there are (s on the stack, ()s were unbalanced - $output[] = $op; - } - return $output; - } + $ops = array('+','-','*','/','^','_'); + $ops_r = array('+' => 0,'-' => 0,'*' => 0,'/' => 0,'^' => 1); // right-associative operator? + $ops_p = array('+' => 0,'-' => 0,'*' => 1,'/' => 1,'_' => 1,'^' => 2); // operator precedence + $expecting_op = false; // we use this in syntax-checking the expression + // and determining when a - is a negation - /** - * evaluate postfix notation - * - * @param string $tokens Expression - * @param array $vars Array - * @return string Output - */ - function pfx($tokens, $vars = array()) { + $matches = array(); + if (preg_match("/[^\w\s+*^\/()\.,-]/", $expr, $matches)) { // make sure the characters are all good + return $this->trigger(4, "illegal character '{$matches[0]}'", $matches[0]); + } - if ($tokens == false) return false; + while (1) { // 1 Infinite Loop ;) + $op = substr($expr, $index, 1); // get the first character at the current index + // find out if we're currently at the beginning of a number/variable/function/parenthesis/operand + $match = array(); + $ex = preg_match('/^([a-z]\w*\(?|\d+(?:\.\d*)?|\.\d+|\()/', substr($expr, $index), $match); + // =============== + if ($op == '-' and ! $expecting_op) { // is it a negation instead of a minus? + $stack->push('_'); // put a negation on the stack + $index ++; + } elseif ($op == '_') { // we have to explicitly deny this, because it's legal on the stack + return $this->trigger(4, "illegal character '_'", "_"); // but not in the input expression + // =============== + } elseif ((in_array($op, $ops) or $ex) and $expecting_op) { // are we putting an operator on the stack? + if ($ex) { // are we expecting an operator but have a number/variable/function/opening parethesis? + $op = '*'; + $index --; // it's an implicit multiplication + } + // heart of the algorithm: + while ($stack->count > 0 and ($o2 = $stack->last()) and in_array($o2, $ops) and ($ops_r[$op] ? $ops_p[$op] < $ops_p[$o2] : $ops_p[$op] <= $ops_p[$o2])) { + $output[] = $stack->pop(); // pop stuff off the stack into the output + } + // many thanks: http://en.wikipedia.org/wiki/Reverse_Polish_notation#The_algorithm_in_detail + $stack->push($op); // finally put OUR operator onto the stack + $index ++; + $expecting_op = false; + // =============== + } elseif ($op == ')' and $expecting_op) { // ready to close a parenthesis? + while (($o2 = $stack->pop()) != '(') { // pop off the stack back to the last ( + if (is_null($o2)) + return $this->trigger(5, "unexpected ')'", ")"); + else + $output[] = $o2; + } + if (preg_match("/^([a-z]\w*)\($/", $stack->last(2), $matches)) { // did we just close a function? + $fnn = $matches[1]; // get the function name + $arg_count = $stack->pop(); // see how many arguments there were (cleverly stored on the stack, thank you) + $output[] = $stack->pop(); // pop the function and push onto the output + if (in_array($fnn, $this->fb)) { // check the argument count + if ($arg_count > 1) + return $this->trigger(6, "wrong number of arguments ($arg_count given, 1 expected)", array($arg_count,1)); + } elseif (array_key_exists($fnn, $this->f)) { + if ($arg_count != count($this->f[$fnn]['args'])) + return $this->trigger(6, "wrong number of arguments ($arg_count given, " . count($this->f[$fnn]['args']) . " expected)", array($arg_count,count($this->f[$fnn]['args']))); + } else { // did we somehow push a non-function on the stack? this should never happen + return $this->trigger(7, "internal error"); + } + } + $index ++; + // =============== + } elseif ($op == ',' and $expecting_op) { // did we just finish a function argument? + while (($o2 = $stack->pop()) != '(') { + if (is_null($o2)) + return $this->trigger(5, "unexpected ','", ","); // oops, never had a ( + else + $output[] = $o2; // pop the argument expression stuff and push onto the output + } + // make sure there was a function + if (! preg_match("/^([a-z]\w*)\($/", $stack->last(2), $matches)) + return $this->trigger(5, "unexpected ','", ","); + $stack->push($stack->pop() + 1); // increment the argument count + $stack->push('('); // put the ( back on, we'll need to pop back to it again + $index ++; + $expecting_op = false; + // =============== + } elseif ($op == '(' and ! $expecting_op) { + $stack->push('('); // that was easy + $index ++; + $allow_neg = true; + // =============== + } elseif ($ex and ! $expecting_op) { // do we now have a function/variable/number? + $expecting_op = true; + $val = $match[1]; + if (preg_match("/^([a-z]\w*)\($/", $val, $matches)) { // may be func, or variable w/ implicit multiplication against parentheses... + if (in_array($matches[1], $this->fb) or array_key_exists($matches[1], $this->f)) { // it's a func + $stack->push($val); + $stack->push(1); + $stack->push('('); + $expecting_op = false; + } else { // it's a var w/ implicit multiplication + $val = $matches[1]; + $output[] = $val; + } + } else { // it's a plain old var or num + $output[] = $val; + } + $index += strlen($val); + // =============== + } elseif ($op == ')') { // miscellaneous error checking + return $this->trigger(5, "unexpected ')'", ")"); + } elseif (in_array($op, $ops) and ! $expecting_op) { + return $this->trigger(8, "unexpected operator '$op'", $op); + } else { // I don't even want to know what you did to get here + return $this->trigger(9, "an unexpected error occured"); + } + if ($index == strlen($expr)) { + if (in_array($op, $ops)) { // did we end with an operator? bad. + return $this->trigger(10, "operator '$op' lacks operand", $op); + } else { + break; + } + } + while (substr($expr, $index, 1) == ' ') { // step the index past whitespace (pretty much turns whitespace + $index ++; // into implicit multiplication if no operator is there) + } + } + while (! is_null($op = $stack->pop())) { // pop everything off the stack and push onto output + if ($op == '(') + return $this->trigger(11, "expecting ')'", ")"); // if there are (s on the stack, ()s were unbalanced + $output[] = $op; + } + return $output; + } - $stack = new EvalMathStack(); + /** + * evaluate postfix notation + * + * @param string $tokens + * Expression + * @param array $vars + * Array + * @return string Output + */ + function pfx($tokens, $vars = array()) + { + if ($tokens == false) + return false; - foreach ($tokens as $token) { // nice and easy - // if the token is a binary operator, pop two values off the stack, do the operation, and push the result back on - if (in_array($token, array('+', '-', '*', '/', '^'))) { - if (is_null($op2 = $stack->pop())) return $this->trigger(12, "internal error"); - if (is_null($op1 = $stack->pop())) return $this->trigger(13, "internal error"); - switch ($token) { - case '+': - $stack->push($op1+$op2); break; - case '-': - $stack->push($op1-$op2); break; - case '*': - $stack->push($op1*$op2); break; - case '/': - if ($op2 == 0) return $this->trigger(14, "division by zero"); - $stack->push($op1/$op2); break; - case '^': - $stack->push(pow($op1, $op2)); break; - } - // if the token is a unary operator, pop one value off the stack, do the operation, and push it back on - } elseif ($token == "_") { - $stack->push(-1*$stack->pop()); - // if the token is a function, pop arguments off the stack, hand them to the function, and push the result back on - } elseif (preg_match("/^([a-z]\w*)\($/", $token, $matches)) { // it's a function! - $fnn = $matches[1]; - if (in_array($fnn, $this->fb)) { // built-in function: - if (is_null($op1 = $stack->pop())) return $this->trigger(15, "internal error"); - $fnn = preg_replace("/^arc/", "a", $fnn); // for the 'arc' trig synonyms - if ($fnn == 'ln') $fnn = 'log'; - eval('$stack->push(' . $fnn . '($op1));'); // perfectly safe eval() - } elseif (array_key_exists($fnn, $this->f)) { // user function - // get args - $args = array(); - for ($i = count($this->f[$fnn]['args'])-1; $i >= 0; $i--) { - if (is_null($args[$this->f[$fnn]['args'][$i]] = $stack->pop())) return $this->trigger(16, "internal error"); - } - $stack->push($this->pfx($this->f[$fnn]['func'], $args)); // yay... recursion!!!! - } - // if the token is a number or variable, push it on the stack - } else { - if (is_numeric($token)) { - $stack->push($token); - } elseif (array_key_exists($token, $this->v)) { - $stack->push($this->v[$token]); - } elseif (array_key_exists($token, $vars)) { - $stack->push($vars[$token]); - } else { - return $this->trigger(17, "undefined variable '$token'", $token); - } - } - } - // when we're out of tokens, the stack should have a single element, the final result - if ($stack->count != 1) return $this->trigger(18, "internal error"); - return $stack->pop(); - } + $stack = new EvalMathStack(); - /** - * trigger an error, but nicely, if need be - * - * @param string $code Code - * @param string $msg Msg - * @param string|null $info sting - * @return boolean False - */ - function trigger($code, $msg, $info = null) { - $this->last_error = $msg; - $this->last_error_code = array($code, $info); - if (!$this->suppress_errors) trigger_error($msg, E_USER_WARNING); - return false; - } + foreach ($tokens as $token) { // nice and easy + // if the token is a binary operator, pop two values off the stack, do the operation, and push the result back on + $matches = array(); + if (in_array($token, array('+','-','*','/','^'))) { + if (is_null($op2 = $stack->pop())) + return $this->trigger(12, "internal error"); + if (is_null($op1 = $stack->pop())) + return $this->trigger(13, "internal error"); + switch ($token) { + case '+': + $stack->push($op1 + $op2); + break; + case '-': + $stack->push($op1 - $op2); + break; + case '*': + $stack->push($op1 * $op2); + break; + case '/': + if ($op2 == 0) + return $this->trigger(14, "division by zero"); + $stack->push($op1 / $op2); + break; + case '^': + $stack->push(pow($op1, $op2)); + break; + } + // if the token is a unary operator, pop one value off the stack, do the operation, and push it back on + } elseif ($token == "_") { + $stack->push(- 1 * $stack->pop()); + // if the token is a function, pop arguments off the stack, hand them to the function, and push the result back on + } elseif (preg_match("/^([a-z]\w*)\($/", $token, $matches)) { // it's a function! + $fnn = $matches[1]; + if (in_array($fnn, $this->fb)) { // built-in function: + if (is_null($op1 = $stack->pop())) + return $this->trigger(15, "internal error"); + $fnn = preg_replace("/^arc/", "a", $fnn); // for the 'arc' trig synonyms + if ($fnn == 'ln') + $fnn = 'log'; + eval('$stack->push(' . $fnn . '($op1));'); // perfectly safe eval() + } elseif (array_key_exists($fnn, $this->f)) { // user function + // get args + $args = array(); + for ($i = count($this->f[$fnn]['args']) - 1; $i >= 0; $i --) { + if (is_null($args[$this->f[$fnn]['args'][$i]] = $stack->pop())) + return $this->trigger(16, "internal error"); + } + $stack->push($this->pfx($this->f[$fnn]['func'], $args)); // yay... recursion!!!! + } + // if the token is a number or variable, push it on the stack + } else { + if (is_numeric($token)) { + $stack->push($token); + } elseif (array_key_exists($token, $this->v)) { + $stack->push($this->v[$token]); + } elseif (array_key_exists($token, $vars)) { + $stack->push($vars[$token]); + } else { + return $this->trigger(17, "undefined variable '$token'", $token); + } + } + } + // when we're out of tokens, the stack should have a single element, the final result + if ($stack->count != 1) + return $this->trigger(18, "internal error"); + return $stack->pop(); + } + + /** + * trigger an error, but nicely, if need be + * + * @param string $code + * Code + * @param string $msg + * Msg + * @param string|null $info + * sting + * @return boolean False + */ + function trigger($code, $msg, $info = null) + { + $this->last_error = $msg; + $this->last_error_code = array($code,$info); + if (! $this->suppress_errors) + trigger_error($msg, E_USER_WARNING); + return false; + } } /** - * Class for internal use - */ + * Class for internal use + */ class EvalMathStack { - var $stack = array(); - var $count = 0; - /** - * push - * - * @param string $val Val - * @return void - */ - function push($val) { - $this->stack[$this->count] = $val; - $this->count++; - } + var $stack = array(); - /** - * pop - * - * @return mixed Stack - */ - function pop() { - if ($this->count > 0) { - $this->count--; - return $this->stack[$this->count]; - } - return null; - } + var $count = 0; - /** - * last - * - * @param int $n N - * @return mixed Stack - */ - function last($n=1) { - if (isset($this->stack[$this->count-$n])) { - return $this->stack[$this->count-$n]; - } - return; - } + /** + * push + * + * @param string $val + * Val + * @return void + */ + function push($val) + { + $this->stack[$this->count] = $val; + $this->count ++; + } + + /** + * pop + * + * @return mixed Stack + */ + function pop() + { + if ($this->count > 0) { + $this->count --; + return $this->stack[$this->count]; + } + return null; + } + + /** + * last + * + * @param int $n + * N + * @return mixed Stack + */ + function last($n = 1) + { + if (isset($this->stack[$this->count - $n])) { + return $this->stack[$this->count - $n]; + } + return; + } }