user: 请将这段汇编代码片段转换成等效的C代码:

```asm
<longestValidParentheses2>:
  endbr64
  push   %r12
  xor    %r12d,%r12d
  push   %rbx
  sub    $0x8,%rsp
  test   %rdi,%rdi
  je     L165
  mov    %rdi,%rbx
  call   <strlen@plt>
  lea    0x1(%rax),%edi
  mov    %eax,%r12d
  call   <malloc@plt>
  mov    %rax,%rdi
  test   %rax,%rax
  je     L289
  movslq %r12d,%rsi
  mov    %rdi,%rcx
  mov    %rdi,%rdx
  add    %rax,%rsi
  movzbl (%rbx),%eax
  test   %al,%al
  jne    L272
  jmp    L65
  nopl   0x0(%rax,%rax,1)
L245:
  cmp    $0x29,%al
  jne    L18
  movzbl -0x1(%rdx),%eax
  cmp    %rdx,%rdi
  je     L24
  cmp    $0x28,%al
  je     L249
L24:
  cmp    $0x2a,%al
  je     L51
L235:
  cmp    %rdx,%rsi
  je     L18
  movb   $0x29,(%rdx)
  add    $0x1,%rdx
L18:
  movzbl 0x1(%rbx),%eax
  add    $0x1,%rbx
  test   %al,%al
  je     L65
L272:
  cmp    $0x28,%al
  jne    L245
  add    $0x1,%rbx
  movb   $0x28,(%rdx)
  add    $0x1,%rdx
  movzbl (%rbx),%eax
  test   %al,%al
  jne    L272
L65:
  test   %r12d,%r12d
  jle    L248
  lea    -0x1(%r12),%edx
  mov    %rdi,%rax
  xor    %ecx,%ecx
  lea    0x1(%rdi,%rdx,1),%rsi
  xor    %edx,%edx
  jmp    L174
  nopw   0x0(%rax,%rax,1)
L99:
  cmp    %edx,%ecx
  cmovl  %edx,%ecx
  add    $0x1,%rax
  xor    %edx,%edx
  cmp    %rax,%rsi
  je     L3
L174:
  cmpb   $0x2a,(%rax)
  jne    L99
  add    $0x1,%rax
  add    $0x2,%edx
  cmp    %rax,%rsi
  jne    L174
L3:
  cmp    %edx,%ecx
  cmovge %ecx,%edx
  mov    %edx,%r12d
L25:
  call   <free@plt>
L165:
  add    $0x8,%rsp
  mov    %r12d,%eax
  pop    %rbx
  pop    %r12
  ret
  nopl   0x0(%rax)
L51:
  cmpb   $0x28,(%rcx)
  jne    L235
  movb   $0x2a,(%rcx)
  cmp    %rcx,%rdi
  je     L18
  nopl   (%rax)
L55:
  sub    $0x1,%rcx
  cmp    %rcx,%rdi
  je     L18
  cmpb   $0x2a,(%rcx)
  je     L55
  jmp    L18
  nop
L249:
  lea    -0x1(%rdx),%rax
  movb   $0x2a,-0x1(%rdx)
  cmp    %rax,%rdi
  je     L18
  lea    -0x2(%rdx),%rcx
  cmp    %rcx,%rdi
  je     L18
  cmpb   $0x2a,(%rcx)
  jne    L18
  nopw   0x0(%rax,%rax,1)
L72:
  sub    $0x1,%rcx
  cmp    %rcx,%rdi
  je     L18
  cmpb   $0x2a,(%rcx)
  je     L72
  jmp    L18
  nopw   0x0(%rax,%rax,1)
L248:
  xor    %r12d,%r12d
  jmp    L25
L289:
  mov    $0xffffffff,%r12d
  jmp    L165
```

assistant: ```c
int longestValidParentheses2(char *s) {
  if (s == NULL) {
    return 0;
  }
  int maxLen = 0;
  int curLen = 0;
  int sLen = strlen(s);
  char *stack = (char *)malloc((sLen + 1) * sizeof(char));
  if (stack == NULL) {
    return -1;
  }
  char *pStack = stack;
  char *stackEnd = stack + sLen;
  char *stackPre = stack;
  ;
  while (*s) {
    switch (*s) {
    case '(':
      *pStack = *s;
      pStack++;
      break;
    case ')':
      if (pStack != stack && *(pStack - 1) == '(') {
        *(pStack - 1) = '*';
        if (pStack - 1 != stack) {
          stackPre = pStack - 2;
          while (stackPre != stack && *stackPre == '*') {
            stackPre--;
          }
        }
      } else if (*(pStack - 1) == '*') {
        if (*stackPre == '(') {
          *stackPre = '*';
          while (stackPre != stack && *stackPre == '*') {
            stackPre--;
          }
        } else if (pStack != stackEnd) {
          *pStack = ')';
          pStack++;
        }
      } else if (pStack != stackEnd) {
        *pStack = ')';
        pStack++;
      }
      break;
    }
    s++;
  }
  pStack = stack;
  int i = 0;
  for (i = 0; i < sLen; i++) {
    if (pStack[i] == '*') {
      curLen += 2;
    } else {
      if (curLen > maxLen) {
        maxLen = curLen;
      }
      curLen = 0;
    }
  }
  if (curLen > maxLen) {
    maxLen = curLen;
  }
  free(stack);
  return maxLen;
}
```