user: 请将以下的汇编代码转换成C语言代码：

```asm
<test_preexisting>:
  endbr64
  push   %r13
  push   %r12
  push   %rbp
  push   %rbx
  sub    $0x468,%rsp
  mov    %fs:0x28,%rax
  mov    %rax,0x458(%rsp)
  xor    %eax,%eax
  movabs $0x6972772074736554,%rax
  movabs $0x6d6f7320676e6974,%rdx
  mov    %rax,0x10(%rsp)
  mov    %rdx,0x18(%rsp)
  movabs $0x66667574732065,%rax
  mov    %rax,0x20(%rsp)
  movabs $0x4141414141414141,%rcx
  mov    %rcx,0x6(%rsp)
  movw   $0x41,0xe(%rsp)
  movabs $0x6972772041414141,%rcx
  movabs $0x6d6f7320676e6974,%rbx
  mov    %rcx,0x30(%rsp)
  mov    %rbx,0x38(%rsp)
  mov    %rax,0x40(%rsp)
  lea    0x50(%rsp),%r12
  lea    D0(%rip),%r13
  mov    %r13,%rdx
  mov    $0x200,%esi
  mov    %r12,%rdi
  call   <fmemopen@plt>
  mov    %rax,%rbx
  test   %rax,%rax
  setne  %dil
  movzbl %dil,%edi
  call   <assert@plt>
  lea    0x10(%rsp),%rbp
  mov    %rbx,%rcx
  mov    $0x18,%edx
  mov    $0x1,%esi
  mov    %rbp,%rdi
  call   <fwrite@plt>
  cmp    $0x18,%rax
  sete   %dil
  movzbl %dil,%edi
  call   <assert@plt>
  mov    %rbx,%rdi
  call   <fclose@plt>
  test   %eax,%eax
  sete   %dil
  movzbl %dil,%edi
  call   <assert@plt>
  lea    D15(%rip),%rdx
  mov    $0x200,%esi
  mov    %r12,%rdi
  call   <fmemopen@plt>
  mov    %rax,%rbx
  test   %rax,%rax
  setne  %dil
  movzbl %dil,%edi
  call   <assert@plt>
  lea    0x250(%rsp),%r12
  mov    $0x200,%esi
  mov    %r12,%rdi
  call   <bzero@plt>
  mov    %rbx,%rcx
  mov    $0x200,%edx
  mov    $0x1,%esi
  mov    %r12,%rdi
  call   <fread@plt>
  cmp    $0x200,%rax
  sete   %dil
  movzbl %dil,%edi
  call   <assert@plt>
  mov    %r12,%rsi
  mov    %rbp,%rdi
  call   <strcmp@plt>
  test   %rax,%rax
  sete   %dil
  movzbl %dil,%edi
  call   <assert@plt>
  mov    %rbx,%rdi
  call   <fclose@plt>
  test   %eax,%eax
  sete   %dil
  movzbl %dil,%edi
  call   <assert@plt>
  mov    %r13,%rdx
  mov    $0x4,%esi
  mov    %rbp,%rdi
  call   <fmemopen@plt>
  mov    %rax,%rbx
  test   %rax,%rax
  setne  %dil
  movzbl %dil,%edi
  call   <assert@plt>
  lea    0x6(%rsp),%rdi
  mov    %rbx,%rcx
  mov    $0xa,%edx
  mov    $0x1,%esi
  call   <fwrite@plt>
  cmp    $0x4,%rax
  sete   %dil
  movzbl %dil,%edi
  call   <assert@plt>
  mov    %rbx,%rdi
  call   <fclose@plt>
  lea    0x30(%rsp),%rsi
  mov    %rbp,%rdi
  call   <strcmp@plt>
  test   %rax,%rax
  sete   %dil
  movzbl %dil,%edi
  call   <assert@plt>
  mov    0x458(%rsp),%rax
  sub    %fs:0x28,%rax
  jne    L2
  add    $0x468,%rsp
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  ret
L2:
  call   <__stack_chk_fail@plt>
```

tool_calls: name: extract_symbolic_data
arguments: tag: D0
type_infered: string
name: extract_symbolic_data
arguments: tag: D15
type_infered: string

tool: D0: w

tool: D15: r

assistant: ```c
void test_preexisting() {
  char buf[512];
  char buf2[512];
  char str[] = "Test writing some stuff";
  char str2[] = "AAAAAAAAA";
  char str3[] = "AAAA writing some stuff";
  FILE *fp;
  size_t nofw, nofr;
  int rc;
  fp = fmemopen(buf, sizeof(buf), "w");
  assert(fp != NULL);
  nofw = fwrite(str, 1, sizeof(str), fp);
  assert(nofw == sizeof(str));
  rc = fclose(fp);
  assert(rc == 0);
  fp = fmemopen(buf, sizeof(buf), "r");
  assert(fp != NULL);
  bzero(buf2, sizeof(buf2));
  nofr = fread(buf2, 1, sizeof(buf2), fp);
  assert(nofr == sizeof(buf2));
  assert(strcmp(str, buf2) == 0);
  rc = fclose(fp);
  assert(rc == 0);
  fp = fmemopen(str, 4, "w");
  assert(fp != NULL);
  nofw = fwrite(str2, 1, sizeof(str2), fp);
  assert(nofw == 4);
  rc = fclose(fp);
  assert(strcmp(str, str3) == 0);
}
```