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Fix phpcs

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Laurent Destailleur 2020-03-13 11:29:27 +01:00
parent d3447bb44b
commit 893ae21d3a
1 changed files with 454 additions and 403 deletions
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htdocs/core/class/evalmath.class.php
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@ -1,4 +1,5 @@
<?php <?php
/* /*
* ================================================================================ * ================================================================================
* *
@ -8,460 +9,510 @@
* ================================================================================ * ================================================================================
* *
* NAME * NAME
* EvalMath - safely evaluate math expressions * EvalMath - safely evaluate math expressions
* *
* SYNOPSIS * SYNOPSIS
* include('evalmath.class.php'); * include('evalmath.class.php');
* $m = new EvalMath; * $m = new EvalMath;
* // basic evaluation: * // basic evaluation:
* $result = $m->evaluate('2+2'); * $result = $m->evaluate('2+2');
* // supports: order of operation; parentheses; negation; built-in functions * // supports: order of operation; parentheses; negation; built-in functions
* $result = $m->evaluate('-8(5/2)^2*(1-sqrt(4))-8'); * $result = $m->evaluate('-8(5/2)^2*(1-sqrt(4))-8');
* // create your own variables * // create your own variables
* $m->evaluate('a = e^(ln(pi))'); * $m->evaluate('a = e^(ln(pi))');
* // or functions * // or functions
* $m->evaluate('f(x,y) = x^2 + y^2 - 2x*y + 1'); * $m->evaluate('f(x,y) = x^2 + y^2 - 2x*y + 1');
* // and then use them * // and then use them
* $result = $m->evaluate('3*f(42,a)'); * $result = $m->evaluate('3*f(42,a)');
* *
* DESCRIPTION * DESCRIPTION
* Use the EvalMath class when you want to evaluate mathematical expressions * Use the EvalMath class when you want to evaluate mathematical expressions
* from untrusted sources. You can define your own variables and functions, * from untrusted sources. You can define your own variables and functions,
* which are stored in the object. Try it, it's fun! * which are stored in the object. Try it, it's fun!
* *
* METHODS * METHODS
* $m->evalute($expr) * $m->evalute($expr)
* Evaluates the expression and returns the result. If an error occurs, * Evaluates the expression and returns the result. If an error occurs,
* prints a warning and returns false. If $expr is a function assignment, * prints a warning and returns false. If $expr is a function assignment,
* returns true on success. * returns true on success.
* *
* $m->e($expr) * $m->e($expr)
* A synonym for $m->evaluate(). * A synonym for $m->evaluate().
* *
* $m->vars() * $m->vars()
* Returns an associative array of all user-defined variables and values. * Returns an associative array of all user-defined variables and values.
* *
* $m->funcs() * $m->funcs()
* Returns an array of all user-defined functions. * Returns an array of all user-defined functions.
* *
* PARAMETERS * PARAMETERS
* $m->suppress_errors * $m->suppress_errors
* Set to true to turn off warnings when evaluating expressions * Set to true to turn off warnings when evaluating expressions
* *
* $m->last_error * $m->last_error
* If the last evaluation failed, contains a string describing the error. * If the last evaluation failed, contains a string describing the error.
* (Useful when suppress_errors is on). * (Useful when suppress_errors is on).
* *
* $m->last_error_code * $m->last_error_code
* If the last evaluation failed, 2 element array with numeric code and extra info * If the last evaluation failed, 2 element array with numeric code and extra info
* *
* AUTHOR INFORMATION * AUTHOR INFORMATION
* Copyright 2005, Miles Kaufmann. * Copyright 2005, Miles Kaufmann.
* *
* LICENSE * LICENSE
* Redistribution and use in source and binary forms, with or without * Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are * modification, are permitted provided that the following conditions are
* met: * met:
* *
* 1 Redistributions of source code must retain the above copyright * 1 Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer. * notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright * 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the * notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution. * documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote * 3. The name of the author may not be used to endorse or promote
* products derived from this software without specific prior written * products derived from this software without specific prior written
* permission. * permission.
* *
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE. * POSSIBILITY OF SUCH DAMAGE.
*/ */
/** /**
* \file core/class/evalmath.class.php * \file core/class/evalmath.class.php
* \ingroup core * \ingroup core
* \brief This file for Math evaluation * \brief This file for Math evaluation
*/ */
/** /**
* Class EvalMath * Class EvalMath
*/ */
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 $suppress_errors = false;
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 $last_error = null;
* Constructor
*/
function __construct() {
// make the variables a little more accurate
$this->v['pi'] = pi();
$this->v['e'] = exp(1);
}
/** public $last_error_code = null;
* Evaluate
*
* @param string $expr String
* @return boolean|number|NULL|mixed Result
*/
function e($expr) {
return $this->evaluate($expr);
}
/** public $v = array('e' => 2.71,'pi' => 3.14159);
* 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
}
}
/** // variables (and constants)
* vars public $f = array();
*
* @return string Output
*/
function vars() {
$output = $this->v;
unset($output['pi']);
unset($output['e']);
return $output;
}
/** // user-defined functions
* vars public $vb = array('e','pi');
*
* @return string Output
*/
function funcs() {
$output = array();
foreach ($this->f as $fnn=>$dat)
$output[] = $fnn . '(' . implode(',', $dat['args']) . ')';
return $output;
}
// 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 * Evaluate
* *
* @param string $expr Expression * @param string $expr
* @return string Output * String
*/ * @return boolean|number|NULL|mixed Result
function nfx($expr) { */
function e($expr)
{
return $this->evaluate($expr);
}
$index = 0; /**
$stack = new EvalMathStack(); * Evaluate
$output = array(); // postfix form of expression, to be passed to pfx() *
$expr = trim(strtolower($expr)); * @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? * vars
$ops_p = array('+'=>0,'-'=>0,'*'=>1,'/'=>1,'_'=>1,'^'=>2); // operator precedence *
* @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 // ===================== HERE BE INTERNAL METHODS ====================\\
return $this->trigger(4, "illegal character '{$matches[0]}'", $matches[0]);
}
while(1) { // 1 Infinite Loop ;) /**
$op = substr($expr, $index, 1); // get the first character at the current index * Convert infix to postfix notation
// 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); * @param string $expr
//=============== * Expression
if ($op == '-' and !$expecting_op) { // is it a negation instead of a minus? * @return string Output
$stack->push('_'); // put a negation on the stack */
$index++; function nfx($expr)
} 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 $index = 0;
//=============== $stack = new EvalMathStack();
} elseif ((in_array($op, $ops) or $ex) and $expecting_op) { // are we putting an operator on the stack? $output = array(); // postfix form of expression, to be passed to pfx()
if ($ex) { // are we expecting an operator but have a number/variable/function/opening parethesis? $expr = trim(strtolower($expr));
$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)
}
} $ops = array('+','-','*','/','^','_');
while (!is_null($op = $stack->pop())) { // pop everything off the stack and push onto output $ops_r = array('+' => 0,'-' => 0,'*' => 0,'/' => 0,'^' => 1); // right-associative operator?
if ($op == '(') return $this->trigger(11, "expecting ')'", ")"); // if there are (s on the stack, ()s were unbalanced $ops_p = array('+' => 0,'-' => 0,'*' => 1,'/' => 1,'_' => 1,'^' => 2); // operator precedence
$output[] = $op;
}
return $output;
}
$expecting_op = false; // we use this in syntax-checking the expression
// and determining when a - is a negation
/** $matches = array();
* evaluate postfix notation if (preg_match("/[^\w\s+*^\/()\.,-]/", $expr, $matches)) { // make sure the characters are all good
* return $this->trigger(4, "illegal character '{$matches[0]}'", $matches[0]);
* @param string $tokens Expression }
* @param array $vars Array
* @return string Output
*/
function pfx($tokens, $vars = array()) {
if ($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 $stack = new EvalMathStack();
// if the token is a binary operator, pop two values off the stack, do the operation, and push the result back on
if (in_array($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 $stack->pop();
}
/** foreach ($tokens as $token) { // nice and easy
* trigger an error, but nicely, if need be // if the token is a binary operator, pop two values off the stack, do the operation, and push the result back on
* $matches = array();
* @param string $code Code if (in_array($token, array('+','-','*','/','^'))) {
* @param string $msg Msg if (is_null($op2 = $stack->pop()))
* @param string|null $info sting return $this->trigger(12, "internal error");
* @return boolean False if (is_null($op1 = $stack->pop()))
*/ return $this->trigger(13, "internal error");
function trigger($code, $msg, $info = null) { switch ($token) {
$this->last_error = $msg; case '+':
$this->last_error_code = array($code, $info); $stack->push($op1 + $op2);
if (!$this->suppress_errors) trigger_error($msg, E_USER_WARNING); break;
return false; 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 class EvalMathStack
{ {
var $stack = array();
var $count = 0;
/** var $stack = array();
* push
*
* @param string $val Val
* @return void
*/
function push($val) {
$this->stack[$this->count] = $val;
$this->count++;
}
/** var $count = 0;
* pop
*
* @return mixed Stack
*/
function pop() {
if ($this->count > 0) {
$this->count--;
return $this->stack[$this->count];
}
return null;
}
/** /**
* last * push
* *
* @param int $n N * @param string $val
* @return mixed Stack * Val
*/ * @return void
function last($n=1) { */
if (isset($this->stack[$this->count-$n])) { function push($val)
return $this->stack[$this->count-$n]; {
} $this->stack[$this->count] = $val;
return; $this->count ++;
} }
/**
* pop
*
* @return mixed Stack
*/
function pop()
{
if ($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;
}
} }