optimize balanceBackticks

src/PHPSQLParser/lexer/PHPSQLLexer.php

@@ -283,25 +283,30 @@ protected function isBacktick($token) {
     }
 
     protected function balanceBackticks($tokens) {
+        $result = [];
+        $n = count($tokens);
         $i = 0;
-        $cnt = count($tokens);
-        while ($i < $cnt) {
-
-            if (!isset($tokens[$i])) {
-                $i++;
-                continue;
-            }
-
+        while ($i < $n) {
             $token = $tokens[$i];
-
+            // 如果遇到一个反引号，则尝试合并直到找到匹配的结束符
             if ($this->isBacktick($token)) {
-                $tokens = $this->balanceCharacter($tokens, $i, $token);
+                $balanced = $token;
+                $i++;
+                while ($i < $n) {
+                    $balanced .= $tokens[$i];
+                    // 遇到匹配的结束符后退出内层循环
+                    if ($tokens[$i] === $token) {
+                        break;
+                    }
+                    $i++;
+                }
+                $result[] = $balanced;
+            } else {
+                $result[] = $token;
             }
-
             $i++;
         }
-
-        return $tokens;
+        return $result;
     }
 
     // backticks are not balanced within one token, so we have

tests/cases/parser/backtickTest.php

@@ -63,5 +63,43 @@ public function testBacktick() {
         $this->assertEquals($expected, $p, "issue 35: ben's test");
 
     }
+    public function generateRandomString($length = 10)
+    {
+        $characters = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';
+        $randomString = '';
+        for ($i = 0; $i < $length; $i++) {
+            $randomString .= $characters[rand(0, strlen($characters) - 1)];
+        }
+        return $randomString;
+    }
+
+    public function createInFilter($len)
+    {
+        $arr = [];
+        for ($i = 0; $i < $len; $i++) {
+            $arr[] = $this->generateRandomString();
+        }
+        return '("' . implode($arr, '","') . '")';
+    }
+
+    public function testOptimizeBalanceBackticks()
+    {
+        $parser = new PHPSQLParser();
+
+        // test backticks
+        $sql = 'SELECT id, name from test where `id map` in ("a b c 1-2_3")';
+        $obj = $parser->parse($sql);
+        $creator = new PHPSQLCreator($obj);
+        $sql2 = $creator->created;
+        $this->assertTrue(mb_strtolower($sql) === mb_strtolower($sql2));
+
+        // The more in conditions, the worse the performance
+        // The difference before and after optimization is 10 times
+        $sql = 'SELECT id,name from test where id in ' . $this->createInFilter(1024);
+        $start = microtime(true);
+        $parser->parse($sql);
+        $cost = intval((microtime(true) - $start) * 1000);
+        print_r('cost ' . $cost . PHP_EOL);
+    }
 }