相关知识：一元运算符``二元运算符``中缀表达式``后缀表达式
先上测试代码:
$filter = "{is_game_vip}==1";
$data = [
'is_game_vip' => 1,
'age' => 18
];
$value = Filter::exec($filter, $data);
var_dump($value); // 1
var_dump(Filter::exec("18>2")); // 1
var_dump(Filter::exec("1+2")); //3
var_dump(Filter::exec("(1+2)*2")); //6
var_dump(Filter::exec("{age} > 10")); //1
var_dump(Filter::exec("({a}+{b}+{c})*{d}-{f}*{m}", [
'a' => 1,
'b' => 2,
'c' => 3,
'd' => 6,
'f' => 4,
'm' => 5
]));//16
class Filter
{
protected static $operate = [
'(',
')',
'+',
'-',
'*',
'/',
'==',
'>=',
'<=',
'>',
'<',
'!',
'&&',
'||',
'and',
'or',
'<<',
'>>',
'!=',
'&',
'^',
'|',
];
protected static $twoElementOperation = [
'+',
'-',
'*',
'/',
'==',
'>=',
'<=',
'>',
'<',
'&&',
'||',
'and',
'or',
'<<',
'>>',
'!=',
'&',
'^',
'|',
];
protected static $oneElementOperation = ['!'];
public static function exec($filter, $data)
{
$infix = self::stringToOperateArray($filter);
$postfix = self::infixToPostfix($infix);
$data = is_array($data) ? $data : [];
$value = self::calculation($postfix, $data);
return $value;
}
/**
* 将中缀表达式转换为后缀表达式
* @param array $infixExpression
*/
public static function infixToPostfix($infixExpression)
{
$stacks = [];
$output = [];
array_walk($infixExpression, function ($value) use (&$stacks, &$output) {
if (!self::isOperate($value)) {
$output[] = $value;
} else {
if (empty($stacks) || $value == '(' || self::compareOperate($value, end($stacks)) == 1) {
$stacks[] = $value;
} else if ($value == ')') {
while (!empty($stacks) && ($last = array_pop($stacks)) != '(') {
$output[] = $last;
}
} else if (self::compareOperate($value, end($stacks)) <= 0) {
while (!empty($stacks) && end($stacks) != '(') {
if (self::compareOperate(end($stacks), $value) > -1) {
$output[] = array_pop($stacks);
} else {
break;
}
}
$stacks[] = $value;
}
}
});
while (!empty($stacks)) {
$end = array_pop($stacks);
if ($end != '(' && $end != ')') {
$output[] = $end;
}
}
return $output;
}
public static function calculation($postfix, $data)
{
$stacks = [];
array_walk($postfix, function ($value) use ($data, &$stacks) {
if (self::isOperate($value)) {
if (self::getOperateType($value) == 1) {
if (!empty($stacks)) {
$stacks[] = self::oneElementOperation(array_pop($stacks), $value);
}
} else if (self::getOperateType($value) == 2 && count($stacks) >= 2) {
$two = array_pop($stacks);
$one = array_pop($stacks);
$stacks[] = self::twoElementOperateion($one, $two, $value);
}
} else {
if (substr($value, 0, 1) == '{' && substr($value, -1, 1) == '}') {
$value = substr($value, 1, -1);
$stacks[] = array_key_exists($value, $data) ? $data[$value] : 0;
} else {
$stacks[] = $value;
}
}
});
return count($stacks) > 0 ? array_pop($stacks) : 0;
}
/**
* 将字符串转换为中缀表达式
* 采用过滤敏感词的算法
* @param string $string
*/
public static function stringToOperateArray($string)
{
$string = trim($string);
$string = html_entity_decode($string);
$len = strlen($string);
$return = [];
$operateIndex = [];
foreach (self::$operate as $value) {
!isset($operateIndex[$value[0]]) && $operateIndex[$value[0]] = [];
$operateIndex[$value[0]][] = $value;
}
$left = 0;
$i = 0;
while ($i < $len) {
if ($string[$i] == ' ') {
if ($i > $left) {
$return[] = substr($string, $left, $i - $left);
}
$left = $i + 1;
} else if (!empty($operateIndex[$string[$i]])) {
$offset = 0;
$lenValue = 0;
foreach ($operateIndex[$string[$i]] as $value) {
$lenValue = strlen($value);
if (substr($string, $i, $lenValue) == $value) {
$offset = $lenValue > $offset ? $lenValue : $offset;
}
}
if ($offset > 0 && ($string[$i] != '-' || ($left != $i))) {
$i > $left && $return[] = substr($string, $left, $i - $left);
$return[] = substr($string, $i, $offset);
$i = $i + $offset - 1;
$left = $i + 1;
}
}
$i++;
}
if ($len > $left) {
$return[] = substr($string, $left, $len - $left);
}
return $return;
}
protected static function isOperate($string)
{
if (in_array($string, self::$operate)) {
return true;
}
return false;
}
protected static function isString($string)
{
if ($string != ' ' && !self::isOperate($string)) {
return true;
}
return false;
}
/**
* 获取操作符，1元还是2元
*/
protected static function getOperateType($operate)
{
if (in_array($operate, self::$twoElementOperation)) {
return 2;
} else if (in_array($operate, self::$oneElementOperation)) {
return 1;
}
}
protected static function compareOperate($s1, $s2)
{
$weight = [
['*', '/', '%'],
['+', '-', '.'],
['<<', '>>'],
['<', '<=', '>', '>='],
['==', '!=', '===', '!==', '<>', '<=>'],
['&'],
['^'],
['|'],
['&&'],
['||'],
['and'],
['xor'],
['or']
];
foreach ($weight as $value) {
if (in_array($s1, $value)) {
if (in_array($s2, $value)) {
return 0;
} else {
return 1;
}
} else if (in_array($s2, $value)) {
return -1;
}
}
return 0;
}
protected static function twoElementOperateion($a, $b, $operate)
{
switch ($operate) {
case '+' :
return $a + $b;
break;
case '-' :
return $a - $b;
break;
case '*' :
return $a * $b;
break;
case '/' :
return $a / $b;
break;
case '==' :
return $a == $b ? 1 : 0;
break;
case '>=' :
return $a >= $b ? 1 : 0;
break;
case '<=' :
return $a <= $b ? 1 : 0;
break;
case '>' :
return $a > $b ? 1 : 0;
break;
case '<' :
return $a < $b ? 1 : 0;
break;
case '&&' :
return $a && $b ? 1 : 0;
break;
case '||' :
return $a || $b;
break;
case 'and' :
return $a and $b;
break;
case 'or' :
return $a or $b;
break;
case '<<' :
return $a << $b;
break;
case '>>' :
return $a >> $b;
break;
case '!=' :
return $a != $b ? 1 : 0;
break;
case '&' :
return $a & $b;
break;
case '^' :
return $a ^ $b;
break;
case '|' :
return $a | $b;
break;
// case 'xor':
// return $a xor $b;
// break;
default :
return 0;
}
}
protected static function oneElementOperation($a, $operate)
{
switch ($operate) {
case '!' :
return !$a ? 1 : 0;
break;
default :
return 0;
break;
}
}
}
网友评论