diff --git a/src/sqlmap-master/tamper/if2case.py b/src/sqlmap-master/tamper/if2case.py
index 2e3a01f..125f66d 100644
--- a/src/sqlmap-master/tamper/if2case.py
+++ b/src/sqlmap-master/tamper/if2case.py
@@ -5,18 +5,19 @@ Copyright (c) 2006-2024 sqlmap developers (https://sqlmap.org/)
 See the file 'doc/COPYING' for copying permission
 """
 
-from lib.core.compat import xrange
-from lib.core.enums import PRIORITY
-from lib.core.settings import REPLACEMENT_MARKER
+from lib.core.compat import xrange  # 用于兼容Python 2和3的range函数
+from lib.core.enums import PRIORITY  # 导入优先级枚举
+from lib.core.settings import REPLACEMENT_MARKER  # 导入替换标记
 
-__priority__ = PRIORITY.HIGHEST
+__priority__ = PRIORITY.HIGHEST  # 设置优先级为最高
 
 def dependencies():
+    """此函数用于定义此tamper函数的依赖项。当前实现为空，根据需要可以添加具体的依赖项"""
     pass
 
 def tamper(payload, **kwargs):
     """
-    Replaces instances like 'IF(A, B, C)' with 'CASE WHEN (A) THEN (B) ELSE (C) END' counterpart
+    替换IF条件表达式为CASE表达式
 
     Requirement:
         * MySQL
@@ -27,45 +28,43 @@ def tamper(payload, **kwargs):
         * MySQL 5.0 and 5.5
 
     Notes:
-        * Useful to bypass very weak and bespoke web application firewalls
-          that filter the IF() functions
+        * 适用于绕过非常弱且定制的web应用程序防火墙，该防火墙过滤了IF()函数
 
-    >>> tamper('IF(1, 2, 3)')
-    'CASE WHEN (1) THEN (2) ELSE (3) END'
-    >>> tamper('SELECT IF((1=1), (SELECT "foo"), NULL)')
-    'SELECT CASE WHEN (1=1) THEN (SELECT "foo") ELSE (NULL) END'
-    """
-
-    if payload and payload.find("IF") > -1:
-        payload = payload.replace("()", REPLACEMENT_MARKER)
-        while payload.find("IF(") > -1:
-            index = payload.find("IF(")
-            depth = 1
-            commas, end = [], None
-
-            for i in xrange(index + len("IF("), len(payload)):
-                if depth == 1 and payload[i] == ',':
-                    commas.append(i)
+    Examples:
+        >>> tamper('IF(1, 2, 3)')
+        'CASE WHEN (1) THEN (2) ELSE (3) END'
 
-                elif depth == 1 and payload[i] == ')':
-                    end = i
-                    break
-
-                elif payload[i] == '(':
-                    depth += 1
-
-                elif payload[i] == ')':
-                    depth -= 1
+        >>> tamper('SELECT IF((1=1), (SELECT "foo"), NULL)')
+        'SELECT CASE WHEN (1=1) THEN (SELECT "foo") ELSE (NULL) END'
+    """
 
-            if len(commas) == 2 and end:
-                a = payload[index + len("IF("):commas[0]].strip("()")
-                b = payload[commas[0] + 1:commas[1]].lstrip().strip("()")
-                c = payload[commas[1] + 1:end].lstrip().strip("()")
-                newVal = "CASE WHEN (%s) THEN (%s) ELSE (%s) END" % (a, b, c)
-                payload = payload[:index] + newVal + payload[end + 1:]
+    if payload and payload.find("IF") > -1:  # 检查payload是否包含IF
+        payload = payload.replace("()", REPLACEMENT_MARKER)  # 替换空的()为REPLACEMENT_MARKER
+        while payload.find("IF(") > -1:  # 检查payload中是否还包含IF(
+            index = payload.find("IF(")  # 找到IF(的位置
+            depth = 1  # 初始化深度计数器
+            commas, end = [], None  # 初始化逗号列表和结束位置
+
+            for i in xrange(index + len("IF("), len(payload)):  # 遍历IF(后的子串
+                if depth == 1 and payload[i] == ',':  # 如果深度为1且遇到逗号
+                    commas.append(i)  # 记录逗号位置
+                elif depth == 1 and payload[i] == ')':  # 如果深度为1且遇到右括号
+                    end = i  # 记录结束位置
+                    break  # 结束循环
+                elif payload[i] == '(':  # 如果遇到左括号
+                    depth += 1  # 增加深度
+                elif payload[i] == ')':  # 如果遇到右括号
+                    depth -= 1  # 减少深度
+
+            if len(commas) == 2 and end:  # 如果有2个逗号并且有结束位置
+                a = payload[index + len("IF("):commas[0]].strip("()")  # 提取第一个参数
+                b = payload[commas[0] + 1:commas[1]].lstrip().strip("()")  # 提取第二个参数
+                c = payload[commas[1] + 1:end].lstrip().strip("()")  # 提取第三个参数
+                newVal = "CASE WHEN (%s) THEN (%s) ELSE (%s) END" % (a, b, c)  # 构造CASE表达式
+                payload = payload[:index] + newVal + payload[end + 1:]  # 替换IF()为CASE
             else:
-                break
+                break  # 如果不符合条件，跳出循环
 
-        payload = payload.replace(REPLACEMENT_MARKER, "()")
+        payload = payload.replace(REPLACEMENT_MARKER, "()")  # 将REPLACEMENT_MARKER替换回()，防止影响其他部分
 
-    return payload
+    return payload
\ No newline at end of file