user: 这段汇编代码用C语言表示是什么样的:

```asm
<__dns_parse>:
  endbr64
  push   %r15
  push   %r14
  push   %r13
  push   %r12
  push   %rbp
  push   %rbx
  sub    $0x18,%rsp
  mov    %rcx,(%rsp)
  cmp    $0xb,%esi
  jle    L44
  mov    %rdi,%rbp
  mov    %esi,%r12d
  mov    %rdx,%r15
  mov    $0x0,%edi
  testb  $0xf,0x3(%rbp)
  jne    L23
  lea    0xc(%rbp),%rax
  movzbl 0x4(%rbp),%edx
  shl    $0x8,%edx
  movzbl 0x5(%rbp),%ecx
  add    %ecx,%edx
  movzbl 0x6(%rbp),%edi
  shl    $0x8,%edi
  movzbl 0x7(%rbp),%ecx
  add    %ecx,%edi
  lea    (%rdx,%rdi,1),%ecx
  cmp    $0x40,%ecx
  jg     L311
  lea    -0x1(%rdx),%esi
  movslq %r12d,%rcx
  lea    -0x6(%rbp,%rcx,1),%r8
  test   %edx,%edx
  jne    L415
L74:
  lea    -0x1(%rdi),%r14d
  test   %edi,%edi
  je     L23
  movslq %r12d,%r12
  lea    -0x6(%rbp,%r12,1),%rbx
  mov    %rbx,0x8(%rsp)
  jmp    L126
L288:
  movzbl (%rax),%edx
  cmp    $0xc1,%dl
  ja     L104
  je     L87
  cmp    %r8,%rax
  ja     L58
  cmp    $0x1,%dl
  mov    $0x5,%edx
  sbb    $0xffffffffffffffff,%rdx
L82:
  add    %rdx,%rax
  sub    $0x1,%esi
  cmp    $0xffffffff,%esi
  je     L74
L415:
  mov    %rax,%rdx
  sub    %rbp,%rdx
  cmp    %rcx,%rdx
  jge    L288
L136:
  movzbl (%rax),%edx
  sub    $0x1,%edx
  cmp    $0x7e,%edx
  ja     L288
  add    $0x1,%rax
  mov    %rax,%rdx
  sub    %rbp,%rdx
  cmp    %rcx,%rdx
  jl     L136
  jmp    L288
L87:
  cmpb   $0xff,0x1(%rax)
  je     L103
  cmp    %r8,%rax
  ja     L344
  mov    $0x6,%edx
  jmp    L82
L153:
  movzbl (%rax),%ecx
  cmp    $0xc1,%cl
  ja     L271
  je     L120
  mov    %r12,%rdx
  cmp    0x8(%rsp),%rax
  ja     L286
  cmp    $0x1,%cl
  mov    $0x1,%r13d
  sbb    $0xffffffffffffffff,%r13
L60:
  add    %rax,%r13
  movzbl 0x8(%r13),%ebx
  shl    $0x8,%ebx
  movzbl 0x9(%r13),%eax
  add    %eax,%ebx
  movslq %ebx,%rax
  add    %r13,%rax
  add    %rbp,%rdx
  cmp    %rdx,%rax
  ja     L264
  lea    0xa(%r13),%rdx
  movzbl 0x1(%r13),%esi
  mov    %rbp,%r8
  mov    %ebx,%ecx
  mov    (%rsp),%rdi
  call   *%r15
  test   %eax,%eax
  js     L36
  lea    0xa(%rbx),%eax
  cltq
  add    %r13,%rax
  sub    $0x1,%r14d
  cmp    $0xffffffff,%r14d
  je     L148
L126:
  mov    %rax,%rdx
  sub    %rbp,%rdx
  cmp    %r12,%rdx
  jge    L153
L268:
  movzbl (%rax),%edx
  sub    $0x1,%edx
  cmp    $0x7e,%edx
  ja     L153
  add    $0x1,%rax
  mov    %rax,%rdx
  sub    %rbp,%rdx
  cmp    %r12,%rdx
  jl     L268
  jmp    L153
L120:
  cmpb   $0xff,0x1(%rax)
  je     L28
  mov    %r12,%rdx
  cmp    0x8(%rsp),%rax
  ja     L64
  mov    $0x2,%r13d
  jmp    L60
L44:
  mov    $0xffffffff,%edi
  jmp    L23
L311:
  mov    $0xffffffff,%edi
  jmp    L23
L104:
  mov    $0xffffffff,%edi
L23:
  mov    %edi,%eax
  add    $0x18,%rsp
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
L103:
  mov    $0xffffffff,%edi
  jmp    L23
L58:
  mov    $0xffffffff,%edi
  jmp    L23
L271:
  mov    $0xffffffff,%edi
  jmp    L23
L28:
  mov    $0xffffffff,%edi
  jmp    L23
L286:
  mov    $0xffffffff,%edi
  jmp    L23
L264:
  mov    $0xffffffff,%edi
  jmp    L23
L36:
  mov    $0xffffffff,%edi
  jmp    L23
L148:
  mov    $0x0,%edi
  jmp    L23
L64:
  mov    $0xffffffff,%edi
  jmp    L23
L344:
  mov    $0xffffffff,%edi
  jmp    L23
```

assistant: ```c
int __dns_parse(const unsigned char *r, int rlen, int (*callback)(void *, int, const void *, int, const void *), void *ctx) {
  int qdcount, ancount;
  const unsigned char *p;
  int len;
  if (rlen < 12)
    return -1;
  if ((r[3] & 15))
    return 0;
  p = r + 12;
  qdcount = r[4] * 256 + r[5];
  ancount = r[6] * 256 + r[7];
  if (qdcount + ancount > 64)
    return -1;
  while (qdcount--) {
    while (p - r < rlen && *p - 1U < 127)
      p++;
    if (*p > 193 || (*p == 193 && p[1] > 254) || p > r + rlen - 6)
      return -1;
    p += 5 + !!*p;
  }
  while (ancount--) {
    while (p - r < rlen && *p - 1U < 127)
      p++;
    if (*p > 193 || (*p == 193 && p[1] > 254) || p > r + rlen - 6)
      return -1;
    p += 1 + !!*p;
    len = p[8] * 256 + p[9];
    if (p + len > r + rlen)
      return -1;
    if (callback(ctx, p[1], p + 10, len, r) < 0)
      return -1;
    p += 10 + len;
  }
  return 0;
}
```