user: Converte this assembly snippet into its equivalent C code:

```asm
<longestValidParentheses>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  sub    $0x30,%rsp
  mov    %rdi,-0x28(%rbp)
  mov    -0x28(%rbp),%rax
  mov    %rax,%rdi
  call   <strlen@plt>
  mov    %eax,-0xc(%rbp)
  cmpl   $0x1,-0xc(%rbp)
  jg     L5
  mov    $0x0,%eax
  jmp    L6
L5:
  mov    -0xc(%rbp),%eax
  mov    $0x4,%esi
  mov    %eax,%edi
  call   <calloc@plt>
  mov    %rax,-0x8(%rbp)
  movl   $0x1,-0x18(%rbp)
  jmp    L14
L46:
  mov    -0x18(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x28(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  cmp    $0x29,%al
  jne    L60
  mov    -0x18(%rbp),%eax
  cltq
  shl    $0x2,%rax
  lea    -0x4(%rax),%rdx
  mov    -0x8(%rbp),%rax
  add    %rdx,%rax
  mov    (%rax),%edx
  mov    -0x18(%rbp),%eax
  sub    %edx,%eax
  test   %eax,%eax
  jle    L60
  mov    -0x18(%rbp),%eax
  cltq
  shl    $0x2,%rax
  lea    -0x4(%rax),%rdx
  mov    -0x8(%rbp),%rax
  add    %rdx,%rax
  mov    (%rax),%edx
  mov    -0x18(%rbp),%eax
  sub    %edx,%eax
  cltq
  lea    -0x1(%rax),%rdx
  mov    -0x28(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  cmp    $0x28,%al
  jne    L60
  mov    -0x18(%rbp),%eax
  cltq
  shl    $0x2,%rax
  lea    -0x4(%rax),%rdx
  mov    -0x8(%rbp),%rax
  add    %rdx,%rax
  mov    (%rax),%edx
  mov    -0x18(%rbp),%eax
  cltq
  lea    0x0(,%rax,4),%rcx
  mov    -0x8(%rbp),%rax
  add    %rcx,%rax
  add    $0x2,%edx
  mov    %edx,(%rax)
  mov    -0x18(%rbp),%eax
  cltq
  shl    $0x2,%rax
  lea    -0x4(%rax),%rdx
  mov    -0x8(%rbp),%rax
  add    %rdx,%rax
  mov    (%rax),%edx
  mov    -0x18(%rbp),%eax
  sub    %edx,%eax
  cmp    $0x1,%eax
  jle    L60
  mov    -0x18(%rbp),%eax
  cltq
  lea    0x0(,%rax,4),%rdx
  mov    -0x8(%rbp),%rax
  add    %rdx,%rax
  mov    (%rax),%ecx
  mov    -0x18(%rbp),%eax
  cltq
  shl    $0x2,%rax
  lea    -0x4(%rax),%rdx
  mov    -0x8(%rbp),%rax
  add    %rdx,%rax
  mov    (%rax),%edx
  mov    -0x18(%rbp),%eax
  sub    %edx,%eax
  cltq
  shl    $0x2,%rax
  lea    -0x8(%rax),%rdx
  mov    -0x8(%rbp),%rax
  add    %rdx,%rax
  mov    (%rax),%edx
  mov    -0x18(%rbp),%eax
  cltq
  lea    0x0(,%rax,4),%rsi
  mov    -0x8(%rbp),%rax
  add    %rsi,%rax
  add    %ecx,%edx
  mov    %edx,(%rax)
L60:
  addl   $0x1,-0x18(%rbp)
L14:
  mov    -0x18(%rbp),%eax
  cmp    -0xc(%rbp),%eax
  jl     L46
  movl   $0x0,-0x14(%rbp)
  movl   $0x0,-0x10(%rbp)
  jmp    L0
L41:
  mov    -0x10(%rbp),%eax
  cltq
  lea    0x0(,%rax,4),%rdx
  mov    -0x8(%rbp),%rax
  add    %rdx,%rax
  mov    (%rax),%edx
  mov    -0x14(%rbp),%eax
  mov    %edx,%esi
  mov    %eax,%edi
  call   <max@plt>
  mov    %eax,-0x14(%rbp)
  addl   $0x1,-0x10(%rbp)
L0:
  mov    -0x10(%rbp),%eax
  cmp    -0xc(%rbp),%eax
  jl     L41
  mov    -0x14(%rbp),%eax
L6:
  leave
  ret
```

assistant: ```c
int longestValidParentheses(char *s) {
  int s_len = strlen(s);
  if (s_len <= 1)
    return 0;
  int *f = (int *)calloc(s_len, sizeof(int));
  for (int i = 1; i < s_len; ++i)
    if (s[i] == ')' && i - f[i - 1] - 1 >= 0 && s[i - f[i - 1] - 1] == '(') {
      f[i] = f[i - 1] + 2;
      if (i - f[i - 1] - 2 >= 0)
        f[i] += f[i - f[i - 1] - 2];
    }
  int result = 0;
  for (int i = 0; i < s_len; ++i)
    result = max(result, f[i]);
  return result;
}
```