-<?php\r
-\r
-/*\r
-================================================================================\r
-\r
-EvalMath - PHP Class to safely evaluate math expressions\r
-Copyright (C) 2005 Miles Kaufmann <http://www.twmagic.com/>\r
-\r
-================================================================================\r
-\r
-NAME\r
- EvalMath - safely evaluate math expressions\r
- \r
-SYNOPSIS\r
- <?\r
- include('evalmath.class.php');\r
- $m = new EvalMath;\r
- // basic evaluation:\r
- $result = $m->evaluate('2+2');\r
- // supports: order of operation; parentheses; negation; built-in functions\r
- $result = $m->evaluate('-8(5/2)^2*(1-sqrt(4))-8');\r
- // create your own variables\r
- $m->evaluate('a = e^(ln(pi))');\r
- // or functions\r
- $m->evaluate('f(x,y) = x^2 + y^2 - 2x*y + 1');\r
- // and then use them\r
- $result = $m->evaluate('3*f(42,a)');\r
- ?>\r
- \r
-DESCRIPTION\r
- Use the EvalMath class when you want to evaluate mathematical expressions \r
- from untrusted sources. You can define your own variables and functions,\r
- which are stored in the object. Try it, it's fun!\r
-\r
-METHODS\r
- $m->evalute($expr)\r
- Evaluates the expression and returns the result. If an error occurs,\r
- prints a warning and returns false. If $expr is a function assignment,\r
- returns true on success.\r
- \r
- $m->e($expr)\r
- A synonym for $m->evaluate().\r
- \r
- $m->vars()\r
- Returns an associative array of all user-defined variables and values.\r
- \r
- $m->funcs()\r
- Returns an array of all user-defined functions.\r
-\r
-PARAMETERS\r
- $m->suppress_errors\r
- Set to true to turn off warnings when evaluating expressions\r
-\r
- $m->last_error\r
- If the last evaluation failed, contains a string describing the error.\r
- (Useful when suppress_errors is on).\r
-\r
-AUTHOR INFORMATION\r
- Copyright 2005, Miles Kaufmann.\r
-\r
-LICENSE\r
- Redistribution and use in source and binary forms, with or without\r
- modification, are permitted provided that the following conditions are\r
- met:\r
- \r
- 1 Redistributions of source code must retain the above copyright\r
- notice, this list of conditions and the following disclaimer.\r
- 2. Redistributions in binary form must reproduce the above copyright\r
- notice, this list of conditions and the following disclaimer in the\r
- documentation and/or other materials provided with the distribution.\r
- 3. The name of the author may not be used to endorse or promote\r
- products derived from this software without specific prior written\r
- permission.\r
- \r
- THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR\r
- IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED\r
- WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE\r
- DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,\r
- INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES\r
- (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR\r
- SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)\r
- HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,\r
- STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN\r
- ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE\r
- POSSIBILITY OF SUCH DAMAGE.\r
-\r
-*/\r
-\r
-/**\r
- * This class was heavily modified in order to get usefull spreadsheet emulation ;-)\r
- * skodak\r
- * \r
- */\r
-\r
-class EvalMath {\r
-\r
- var $suppress_errors = false;\r
- var $last_error = null;\r
- \r
- var $v = array(); // variables (and constants)\r
- var $f = array(); // user-defined functions\r
- var $vb = array(); // constants\r
- var $fb = array( // built-in functions\r
- 'sin','sinh','arcsin','asin','arcsinh','asinh',\r
- 'cos','cosh','arccos','acos','arccosh','acosh',\r
- 'tan','tanh','arctan','atan','arctanh','atanh',\r
- 'sqrt','abs','ln','log','exp');\r
-\r
- var $fc = array( // calc functions emulation\r
- 'average'=>array(-1), 'max'=>array(-1), 'min'=>array(-1),\r
- 'mod'=>array(2), 'pi'=>array(0), 'power'=>array(2),\r
- 'round'=>array(1, 2), 'sum'=>array(-1));\r
- \r
- function EvalMath() {\r
- }\r
- \r
- function e($expr) {\r
- return $this->evaluate($expr);\r
- }\r
- \r
- function evaluate($expr) {\r
- $this->last_error = null;\r
- $expr = trim($expr);\r
- if (substr($expr, -1, 1) == ';') $expr = substr($expr, 0, strlen($expr)-1); // strip semicolons at the end\r
- //===============\r
- // is it a variable assignment?\r
- if (preg_match('/^\s*([a-z][a-z0-9]*)\s*=\s*(.+)$/', $expr, $matches)) {\r
- if (in_array($matches[1], $this->vb)) { // make sure we're not assigning to a constant\r
- return $this->trigger("cannot assign to constant '$matches[1]'");\r
- }\r
- if (($tmp = $this->pfx($this->nfx($matches[2]))) === false) return false; // get the result and make sure it's good\r
- $this->v[$matches[1]] = $tmp; // if so, stick it in the variable array\r
- return $this->v[$matches[1]]; // and return the resulting value\r
- //===============\r
- // is it a function assignment?\r
- } elseif (preg_match('/^\s*([a-z][a-z0-9]*)\s*\(\s*([a-z][a-z0-9]*(?:\s*,\s*[a-z][a-z0-9]*)*)\s*\)\s*=\s*(.+)$/', $expr, $matches)) {\r
- $fnn = $matches[1]; // get the function name\r
- if (in_array($matches[1], $this->fb)) { // make sure it isn't built in\r
- return $this->trigger("cannot redefine built-in function '$matches[1]()'");\r
- }\r
- $args = explode(",", preg_replace("/\s+/", "", $matches[2])); // get the arguments\r
- if (($stack = $this->nfx($matches[3])) === false) return false; // see if it can be converted to postfix\r
- for ($i = 0; $i<count($stack); $i++) { // freeze the state of the non-argument variables\r
- $token = $stack[$i];\r
- if (preg_match('/^[a-z][a-z0-9]*$/', $token) and !in_array($token, $args)) {\r
- if (array_key_exists($token, $this->v)) {\r
- $stack[$i] = $this->v[$token];\r
- } else {\r
- return $this->trigger("undefined variable '$token' in function definition");\r
- }\r
- }\r
- }\r
- $this->f[$fnn] = array('args'=>$args, 'func'=>$stack);\r
- return true;\r
- //===============\r
- } else {\r
- return $this->pfx($this->nfx($expr)); // straight up evaluation, woo\r
- }\r
- }\r
- \r
- function vars() {\r
- return $this->v;\r
- }\r
- \r
- function funcs() {\r
- $output = array();\r
- foreach ($this->f as $fnn=>$dat)\r
- $output[] = $fnn . '(' . implode(',', $dat['args']) . ')';\r
- return $output;\r
- }\r
-\r
- //===================== HERE BE INTERNAL METHODS ====================\\\r
-\r
- // Convert infix to postfix notation\r
- function nfx($expr) {\r
- \r
- $index = 0;\r
- $stack = new EvalMathStack;\r
- $output = array(); // postfix form of expression, to be passed to pfx()\r
- $expr = trim(strtolower($expr));\r
- \r
- $ops = array('+', '-', '*', '/', '^', '_');\r
- $ops_r = array('+'=>0,'-'=>0,'*'=>0,'/'=>0,'^'=>1); // right-associative operator? \r
- $ops_p = array('+'=>0,'-'=>0,'*'=>1,'/'=>1,'_'=>1,'^'=>2); // operator precedence\r
- \r
- $expecting_op = false; // we use this in syntax-checking the expression\r
- // and determining when a - is a negation\r
- \r
- if (preg_match("/[^\w\s+*^\/()\.,-]/", $expr, $matches)) { // make sure the characters are all good\r
- return $this->trigger("illegal character '{$matches[0]}'");\r
- }\r
- \r
- while(1) { // 1 Infinite Loop ;)\r
- $op = substr($expr, $index, 1); // get the first character at the current index\r
- // find out if we're currently at the beginning of a number/variable/function/parenthesis/operand\r
- $ex = preg_match('/^([a-z][a-z0-9]*\(?|\d+(?:\.\d*)?|\.\d+|\()/', substr($expr, $index), $match);\r
- //===============\r
- if ($op == '-' and !$expecting_op) { // is it a negation instead of a minus?\r
- $stack->push('_'); // put a negation on the stack\r
- $index++;\r
- } elseif ($op == '_') { // we have to explicitly deny this, because it's legal on the stack \r
- return $this->trigger("illegal character '_'"); // but not in the input expression\r
- //===============\r
- } elseif ((in_array($op, $ops) or $ex) and $expecting_op) { // are we putting an operator on the stack?\r
- if ($ex) { // are we expecting an operator but have a number/variable/function/opening parethesis?\r
- return $this->trigger("expecting operand");\r
- //$op = '*'; $index--; // it's an implicit multiplication\r
- }\r
- // heart of the algorithm:\r
- while($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])) {\r
- $output[] = $stack->pop(); // pop stuff off the stack into the output\r
- }\r
- // many thanks: http://en.wikipedia.org/wiki/Reverse_Polish_notation#The_algorithm_in_detail\r
- $stack->push($op); // finally put OUR operator onto the stack\r
- $index++;\r
- $expecting_op = false;\r
- //===============\r
- } elseif ($op == ')' and $expecting_op) { // ready to close a parenthesis?\r
- while (($o2 = $stack->pop()) != '(') { // pop off the stack back to the last (\r
- if (is_null($o2)) return $this->trigger("unexpected ')'");\r
- else $output[] = $o2;\r
- }\r
- if (preg_match("/^([a-z][a-z0-9]*)\($/", $stack->last(2), $matches)) { // did we just close a function?\r
- $fnn = $matches[1]; // get the function name\r
- $arg_count = $stack->pop(); // see how many arguments there were (cleverly stored on the stack, thank you)\r
- $fn = $stack->pop();\r
- $output[] = array('fn'=>$fn, 'fnn'=>$fnn, 'argcount'=>$arg_count); // send function to output\r
- if (in_array($fnn, $this->fb)) { // check the argument count\r
- if($arg_count > 1)\r
- return $this->trigger("too many arguments ($arg_count given, 1 expected)");\r
- } elseif (array_key_exists($fnn, $this->fc)) {\r
- $counts = $this->fc[$fnn];\r
- if (in_array(-1, $counts) and $arg_count > 0) {}\r
- elseif (!in_array($arg_count, $counts))\r
- return $this->trigger("wrong number of arguments ($arg_count given, " . implode('/',$this->fc[$fnn]) . " expected)");\r
- } elseif (array_key_exists($fnn, $this->f)) {\r
- if ($arg_count != count($this->f[$fnn]['args']))\r
- return $this->trigger("wrong number of arguments ($arg_count given, " . count($this->f[$fnn]['args']) . " expected)");\r
- } else { // did we somehow push a non-function on the stack? this should never happen\r
- return $this->trigger("internal error");\r
- }\r
- }\r
- $index++;\r
- //===============\r
- } elseif ($op == ',' and $expecting_op) { // did we just finish a function argument?\r
- while (($o2 = $stack->pop()) != '(') { \r
- if (is_null($o2)) return $this->trigger("unexpected ','"); // oops, never had a (\r
- else $output[] = $o2; // pop the argument expression stuff and push onto the output\r
- }\r
- // make sure there was a function\r
- if (!preg_match("/^([a-z][a-z0-9]*)\($/", $stack->last(2), $matches))\r
- return $this->trigger("unexpected ','");\r
- $stack->push($stack->pop()+1); // increment the argument count\r
- $stack->push('('); // put the ( back on, we'll need to pop back to it again\r
- $index++;\r
- $expecting_op = false;\r
- //===============\r
- } elseif ($op == '(' and !$expecting_op) {\r
- $stack->push('('); // that was easy\r
- $index++;\r
- $allow_neg = true;\r
- //===============\r
- } elseif ($ex and !$expecting_op) { // do we now have a function/variable/number?\r
- $expecting_op = true;\r
- $val = $match[1];\r
- if (preg_match("/^([a-z][a-z0-9]*)\($/", $val, $matches)) { // may be func, or variable w/ implicit multiplication against parentheses...\r
- if (in_array($matches[1], $this->fb) or array_key_exists($matches[1], $this->f) or array_key_exists($matches[1], $this->fc)) { // it's a func\r
- $stack->push($val);\r
- $stack->push(1);\r
- $stack->push('(');\r
- $expecting_op = false;\r
- } else { // it's a var w/ implicit multiplication\r
- $val = $matches[1];\r
- $output[] = $val;\r
- }\r
- } else { // it's a plain old var or num\r
- $output[] = $val;\r
- }\r
- $index += strlen($val);\r
- //===============\r
- } elseif ($op == ')') {\r
- //it could be only custom function with no params or general error\r
- if ($stack->last() != '(' or $stack->last(2) != 1) return $this->trigger("unexpected ')'");\r
- if (preg_match("/^([a-z][a-z0-9]*)\($/", $stack->last(3), $matches)) { // did we just close a function?\r
- $stack->pop();// (\r
- $stack->pop();// 1\r
- $fn = $stack->pop();\r
- $fnn = $matches[1]; // get the function name\r
- $counts = $this->fc[$fnn];\r
- if (!in_array(0, $counts))\r
- return $this->trigger("wrong number of arguments ($arg_count given, " . implode('/',$this->fc[$fnn]) . " expected)");\r
- $output[] = array('fn'=>$fn, 'fnn'=>$fnn, 'argcount'=>0); // send function to output\r
- $index++;\r
- } else {\r
- return $this->trigger("unexpected ')'");\r
- }\r
- //===============\r
- } elseif (in_array($op, $ops) and !$expecting_op) { // miscellaneous error checking\r
- return $this->trigger("unexpected operator '$op'");\r
- } else { // I don't even want to know what you did to get here\r
- return $this->trigger("an unexpected error occured");\r
- }\r
- if ($index == strlen($expr)) {\r
- if (in_array($op, $ops)) { // did we end with an operator? bad.\r
- return $this->trigger("operator '$op' lacks operand");\r
- } else {\r
- break;\r
- }\r
- }\r
- while (substr($expr, $index, 1) == ' ') { // step the index past whitespace (pretty much turns whitespace \r
- $index++; // into implicit multiplication if no operator is there)\r
- }\r
- \r
- } \r
- while (!is_null($op = $stack->pop())) { // pop everything off the stack and push onto output\r
- if ($op == '(') return $this->trigger("expecting ')'"); // if there are (s on the stack, ()s were unbalanced\r
- $output[] = $op;\r
- }\r
- return $output;\r
- }\r
-\r
- // evaluate postfix notation\r
- function pfx($tokens, $vars = array()) {\r
- \r
- if ($tokens == false) return false;\r
- \r
- $stack = new EvalMathStack;\r
- \r
- foreach ($tokens as $token) { // nice and easy\r
-\r
- // if the token is a function, pop arguments off the stack, hand them to the function, and push the result back on\r
- if (is_array($token)) { // it's a function!\r
- $fnn = $token['fnn'];\r
- $count = $token['argcount'];\r
- if (in_array($fnn, $this->fb)) { // built-in function:\r
- if (is_null($op1 = $stack->pop())) return $this->trigger("internal error");\r
- $fnn = preg_replace("/^arc/", "a", $fnn); // for the 'arc' trig synonyms\r
- if ($fnn == 'ln') $fnn = 'log';\r
- eval('$stack->push(' . $fnn . '($op1));'); // perfectly safe eval()\r
- } elseif (array_key_exists($fnn, $this->fc)) { // calc emulation function\r
- // get args\r
- $args = array();\r
- for ($i = $count-1; $i >= 0; $i--) {\r
- if (is_null($args[] = $stack->pop())) return $this->trigger("internal error");\r
- }\r
- $res = call_user_func(array('EvalMathCalcEmul', $fnn), $args);\r
- if ($res == FALSE) {\r
- return $this->trigger("internal error");\r
- }\r
- $stack->push($res);\r
- } elseif (array_key_exists($fnn, $this->f)) { // user function\r
- // get args\r
- $args = array();\r
- for ($i = count($this->f[$fnn]['args'])-1; $i >= 0; $i--) {\r
- if (is_null($args[$this->f[$fnn]['args'][$i]] = $stack->pop())) return $this->trigger("internal error");\r
- }\r
- $stack->push($this->pfx($this->f[$fnn]['func'], $args)); // yay... recursion!!!!\r
- }\r
- // if the token is a binary operator, pop two values off the stack, do the operation, and push the result back on\r
- } elseif (in_array($token, array('+', '-', '*', '/', '^'), true)) {\r
- if (is_null($op2 = $stack->pop())) return $this->trigger("internal error");\r
- if (is_null($op1 = $stack->pop())) return $this->trigger("internal error");\r
- switch ($token) {\r
- case '+':\r
- $stack->push($op1+$op2); break;\r
- case '-':\r
- $stack->push($op1-$op2); break;\r
- case '*':\r
- $stack->push($op1*$op2); break;\r
- case '/':\r
- if ($op2 == 0) return $this->trigger("division by zero");\r
- $stack->push($op1/$op2); break;\r
- case '^':\r
- $stack->push(pow($op1, $op2)); break;\r
- }\r
- // if the token is a unary operator, pop one value off the stack, do the operation, and push it back on\r
- } elseif ($token == "_") {\r
- $stack->push(-1*$stack->pop());\r
- // if the token is a number or variable, push it on the stack\r
- } else {\r
- if (is_numeric($token)) {\r
- $stack->push($token);\r
- } elseif (array_key_exists($token, $this->v)) {\r
- $stack->push($this->v[$token]);\r
- } elseif (array_key_exists($token, $vars)) {\r
- $stack->push($vars[$token]);\r
- } else {\r
- return $this->trigger("undefined variable '$token'");\r
- }\r
- }\r
- }\r
- // when we're out of tokens, the stack should have a single element, the final result\r
- if ($stack->count != 1) return $this->trigger("internal error");\r
- return $stack->pop();\r
- }\r
- \r
- // trigger an error, but nicely, if need be\r
- function trigger($msg) {\r
- $this->last_error = $msg;\r
- if (!$this->suppress_errors) trigger_error($msg, E_USER_WARNING);\r
- return false;\r
- }\r
-}\r
-\r
-// for internal use\r
-class EvalMathStack {\r
-\r
- var $stack = array();\r
- var $count = 0;\r
- \r
- function push($val) {\r
- $this->stack[$this->count] = $val;\r
- $this->count++;\r
- }\r
- \r
- function pop() {\r
- if ($this->count > 0) {\r
- $this->count--;\r
- return $this->stack[$this->count];\r
- }\r
- return null;\r
- }\r
- \r
- function last($n=1) {\r
- return $this->stack[$this->count-$n];\r
- }\r
-}\r
-\r
-// spreadsheed functions emulation\r
-// watch out for reversed args!!\r
-class EvalMathCalcEmul {\r
-\r
- function average($args) {\r
- return (EvalMathCalcEmul::sum($args)/count($args));\r
- }\r
-\r
- function max($args) {\r
- $res = array_pop($args);\r
- foreach($args as $a) {\r
- if ($res < $a) {\r
- $res = $a;\r
- }\r
- }\r
- return $res;\r
- }\r
-\r
- function min($args) {\r
- $res = array_pop($args);\r
- foreach($args as $a) {\r
- if ($res > $a) {\r
- $res = $a;\r
- }\r
- }\r
- return $res;\r
- }\r
-\r
- function mod($args) {\r
- return $args[1] % $args[0];\r
- }\r
-\r
- function pi($args) {\r
- return pi();\r
- }\r
-\r
- function power($args) {\r
- return $args[1]^$args[0];\r
- }\r
-\r
- function round($args) {\r
- if (count($args)==1) {\r
- return round($args[0]);\r
- } else {\r
- return round($args[1], $args[0]);\r
- }\r
- }\r
-\r
- function sum($args) {\r
- $res = 0;\r
- foreach($args as $a) {\r
- $res += $a;\r
- }\r
- return $res;\r
- }\r
-}\r
+<?php
+
+/*
+================================================================================
+
+EvalMath - PHP Class to safely evaluate math expressions
+Copyright (C) 2005 Miles Kaufmann <http://www.twmagic.com/>
+
+================================================================================
+
+NAME
+ EvalMath - safely evaluate math expressions
+
+SYNOPSIS
+ <?
+ 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!
+
+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->vars()
+ Returns an associative array of all user-defined variables and values.
+
+ $m->funcs()
+ Returns an array of all user-defined functions.
+
+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).
+
+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:
+
+ 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 class was heavily modified in order to get usefull spreadsheet emulation ;-)
+ * skodak
+ *
+ */
+
+class EvalMath {
+
+ var $suppress_errors = false;
+ var $last_error = null;
+
+ var $v = array(); // variables (and constants)
+ var $f = array(); // user-defined functions
+ var $vb = array(); // constants
+ var $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','exp');
+
+ var $fc = array( // calc functions emulation
+ 'average'=>array(-1), 'max'=>array(-1), 'min'=>array(-1),
+ 'mod'=>array(2), 'pi'=>array(0), 'power'=>array(2),
+ 'round'=>array(1, 2), 'sum'=>array(-1));
+
+ function EvalMath() {
+ }
+
+ function e($expr) {
+ return $this->evaluate($expr);
+ }
+
+ function evaluate($expr) {
+ $this->last_error = null;
+ $expr = trim($expr);
+ if (substr($expr, -1, 1) == ';') $expr = substr($expr, 0, strlen($expr)-1); // strip semicolons at the end
+ //===============
+ // is it a variable assignment?
+ if (preg_match('/^\s*([a-z][a-z0-9]*)\s*=\s*(.+)$/', $expr, $matches)) {
+ if (in_array($matches[1], $this->vb)) { // make sure we're not assigning to a constant
+ return $this->trigger("cannot assign to constant '$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][a-z0-9]*)\s*\(\s*([a-z][a-z0-9]*(?:\s*,\s*[a-z][a-z0-9]*)*)\s*\)\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 $this->trigger("cannot redefine built-in function '$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
+ for ($i = 0; $i<count($stack); $i++) { // freeze the state of the non-argument variables
+ $token = $stack[$i];
+ if (preg_match('/^[a-z][a-z0-9]*$/', $token) and !in_array($token, $args)) {
+ if (array_key_exists($token, $this->v)) {
+ $stack[$i] = $this->v[$token];
+ } else {
+ return $this->trigger("undefined variable '$token' in function definition");
+ }
+ }
+ }
+ $this->f[$fnn] = array('args'=>$args, 'func'=>$stack);
+ return true;
+ //===============
+ } else {
+ return $this->pfx($this->nfx($expr)); // straight up evaluation, woo
+ }
+ }
+
+ function vars() {
+ return $this->v;
+ }
+
+ function funcs() {
+ $output = array();
+ foreach ($this->f as $fnn=>$dat)
+ $output[] = $fnn . '(' . implode(',', $dat['args']) . ')';
+ return $output;
+ }
+
+ //===================== HERE BE INTERNAL METHODS ====================\\
+
+ // Convert infix to postfix notation
+ function nfx($expr) {
+
+ $index = 0;
+ $stack = new EvalMathStack;
+ $output = array(); // postfix form of expression, to be passed to pfx()
+ $expr = trim(strtolower($expr));
+
+ $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
+
+ if (preg_match("/[^\w\s+*^\/()\.,-]/", $expr, $matches)) { // make sure the characters are all good
+ return $this->trigger("illegal character '{$matches[0]}'");
+ }
+
+ 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][a-z0-9]*\(?|\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 $this->trigger("illegal character '_'"); // but not in the input expression
+ //===============
+ } elseif ((in_array($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?
+ return $this->trigger("expecting operand");
+ //$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("unexpected ')'");
+ else $output[] = $o2;
+ }
+ if (preg_match("/^([a-z][a-z0-9]*)\($/", $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)
+ $fn = $stack->pop();
+ $output[] = array('fn'=>$fn, 'fnn'=>$fnn, 'argcount'=>$arg_count); // send function to output
+ if (in_array($fnn, $this->fb)) { // check the argument count
+ if($arg_count > 1)
+ return $this->trigger("too many arguments ($arg_count given, 1 expected)");
+ } elseif (array_key_exists($fnn, $this->fc)) {
+ $counts = $this->fc[$fnn];
+ if (in_array(-1, $counts) and $arg_count > 0) {}
+ elseif (!in_array($arg_count, $counts))
+ return $this->trigger("wrong number of arguments ($arg_count given, " . implode('/',$this->fc[$fnn]) . " expected)");
+ } elseif (array_key_exists($fnn, $this->f)) {
+ if ($arg_count != count($this->f[$fnn]['args']))
+ return $this->trigger("wrong number of arguments ($arg_count given, " . count($this->f[$fnn]['args']) . " expected)");
+ } else { // did we somehow push a non-function on the stack? this should never happen
+ return $this->trigger("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("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][a-z0-9]*)\($/", $stack->last(2), $matches))
+ return $this->trigger("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][a-z0-9]*)\($/", $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], $this->f) or array_key_exists($matches[1], $this->fc)) { // 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 ($op == ')') {
+ //it could be only custom function with no params or general error
+ if ($stack->last() != '(' or $stack->last(2) != 1) return $this->trigger("unexpected ')'");
+ if (preg_match("/^([a-z][a-z0-9]*)\($/", $stack->last(3), $matches)) { // did we just close a function?
+ $stack->pop();// (
+ $stack->pop();// 1
+ $fn = $stack->pop();
+ $fnn = $matches[1]; // get the function name
+ $counts = $this->fc[$fnn];
+ if (!in_array(0, $counts))
+ return $this->trigger("wrong number of arguments ($arg_count given, " . implode('/',$this->fc[$fnn]) . " expected)");
+ $output[] = array('fn'=>$fn, 'fnn'=>$fnn, 'argcount'=>0); // send function to output
+ $index++;
+ } else {
+ return $this->trigger("unexpected ')'");
+ }
+ //===============
+ } elseif (in_array($op, $ops) and !$expecting_op) { // miscellaneous error checking
+ return $this->trigger("unexpected operator '$op'");
+ } else { // I don't even want to know what you did to get here
+ return $this->trigger("an unexpected error occured");
+ }
+ if ($index == strlen($expr)) {
+ if (in_array($op, $ops)) { // did we end with an operator? bad.
+ return $this->trigger("operator '$op' lacks operand");
+ } 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("expecting ')'"); // if there are (s on the stack, ()s were unbalanced
+ $output[] = $op;
+ }
+ return $output;
+ }
+
+ // evaluate postfix notation
+ function pfx($tokens, $vars = array()) {
+
+ if ($tokens == false) return false;
+
+ $stack = new EvalMathStack;
+
+ foreach ($tokens as $token) { // nice and easy
+
+ // if the token is a function, pop arguments off the stack, hand them to the function, and push the result back on
+ if (is_array($token)) { // it's a function!
+ $fnn = $token['fnn'];
+ $count = $token['argcount'];
+ if (in_array($fnn, $this->fb)) { // built-in function:
+ if (is_null($op1 = $stack->pop())) return $this->trigger("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->fc)) { // calc emulation function
+ // get args
+ $args = array();
+ for ($i = $count-1; $i >= 0; $i--) {
+ if (is_null($args[] = $stack->pop())) return $this->trigger("internal error");
+ }
+ $res = call_user_func(array('EvalMathCalcEmul', $fnn), $args);
+ if ($res === FALSE) {
+ return $this->trigger("internal error");
+ }
+ $stack->push($res);
+ } 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("internal error");
+ }
+ $stack->push($this->pfx($this->f[$fnn]['func'], $args)); // yay... recursion!!!!
+ }
+ // if the token is a binary operator, pop two values off the stack, do the operation, and push the result back on
+ } elseif (in_array($token, array('+', '-', '*', '/', '^'), true)) {
+ if (is_null($op2 = $stack->pop())) return $this->trigger("internal error");
+ if (is_null($op1 = $stack->pop())) return $this->trigger("internal error");
+ switch ($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("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 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 $this->trigger("undefined variable '$token'");
+ }
+ }
+ }
+ // when we're out of tokens, the stack should have a single element, the final result
+ if ($stack->count != 1) return $this->trigger("internal error");
+ return $stack->pop();
+ }
+
+ // trigger an error, but nicely, if need be
+ function trigger($msg) {
+ $this->last_error = $msg;
+ if (!$this->suppress_errors) trigger_error($msg, E_USER_WARNING);
+ return false;
+ }
+}
+
+// for internal use
+class EvalMathStack {
+
+ var $stack = array();
+ var $count = 0;
+
+ function push($val) {
+ $this->stack[$this->count] = $val;
+ $this->count++;
+ }
+
+ function pop() {
+ if ($this->count > 0) {
+ $this->count--;
+ return $this->stack[$this->count];
+ }
+ return null;
+ }
+
+ function last($n=1) {
+ return $this->stack[$this->count-$n];
+ }
+}
+
+// spreadsheed functions emulation
+// watch out for reversed args!!
+class EvalMathCalcEmul {
+
+ function average($args) {
+ return (EvalMathCalcEmul::sum($args)/count($args));
+ }
+
+ function max($args) {
+ $res = array_pop($args);
+ foreach($args as $a) {
+ if ($res < $a) {
+ $res = $a;
+ }
+ }
+ return $res;
+ }
+
+ function min($args) {
+ $res = array_pop($args);
+ foreach($args as $a) {
+ if ($res > $a) {
+ $res = $a;
+ }
+ }
+ return $res;
+ }
+
+ function mod($args) {
+ return $args[1] % $args[0];
+ }
+
+ function pi($args) {
+ return pi();
+ }
+
+ function power($args) {
+ return $args[1]^$args[0];
+ }
+
+ function round($args) {
+ if (count($args)==1) {
+ return round($args[0]);
+ } else {
+ return round($args[1], $args[0]);
+ }
+ }
+
+ function sum($args) {
+ $res = 0;
+ foreach($args as $a) {
+ $res += $a;
+ }
+ return $res;
+ }
+}
projects / moodle.git / commitdiff