user: 这段汇编代码用C语言表示是什么样的：

```asm
<packline>:
  endbr64
  push   %r15
  push   %r14
  mov    %r8d,%r14d
  push   %r13
  mov    %ecx,%r13d
  push   %r12
  push   %rbp
  mov    %rdi,%rbp
  xor    %edi,%edi
  push   %rbx
  mov    %edx,%ebx
  xor    %edx,%edx
  sub    $0x48,%rsp
  mov    %rsi,0x18(%rsp)
  mov    %r8d,0x10(%rsp)
  lea    0x1(%rsi),%r8
  mov    %fs:0x28,%rax
  mov    %rax,0x38(%rsp)
  xor    %eax,%eax
  movb   $0x0,(%rsi)
  xor    %esi,%esi
  mov    %r8,0x8(%rsp)
  call   <intobyte@plt>
  test   %ebx,%ebx
  mov    0x8(%rsp),%r8
  je     L188
  movslq %r14d,%rax
  mov    %rax,0x8(%rsp)
  nop
L307:
  movzbl 0x0(%rbp),%r9d
  add    0x8(%rsp),%rbp
  sub    $0x1,%ebx
  movzbl 0x0(%rbp),%edx
  cmp    %r9b,%dl
  jne    L270
  test   %ebx,%ebx
  je     L306
  xor    %esi,%esi
  cmpl   $0x1,0x10(%rsp)
  je     L114
  jmp    L238
L48:
  cmp    $0xf,%esi
  je     L57
  test   %ebx,%ebx
  je     L57
L114:
  add    $0x1,%rbp
  add    $0x1,%esi
  sub    $0x1,%ebx
  cmp    %r9b,0x0(%rbp)
  je     L48
L57:
  mov    %r8,%rdx
  mov    $0x5,%edi
  mov    %r9b,0x17(%rsp)
  call   <intobyte@plt>
  movzbl 0x17(%rsp),%esi
  mov    %r13d,%edi
  mov    %rax,%rdx
  call   <intobyte@plt>
  mov    %rax,%r8
L59:
  test   %ebx,%ebx
  jne    L307
L188:
  mov    %r8,%rdx
  xor    %esi,%esi
  mov    $0x8,%edi
  call   <intobyte@plt>
  mov    0x18(%rsp),%rcx
  mov    %rax,%rdx
  sub    %rcx,%rdx
  mov    %dl,(%rcx)
  mov    0x38(%rsp),%rdx
  sub    %fs:0x28,%rdx
  jne    L268
  add    $0x48,%rsp
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
  nopl   0x0(%rax)
L142:
  test   %ebx,%ebx
  je     L57
  cmp    $0xf,%esi
  je     L57
L238:
  add    0x8(%rsp),%rbp
  add    $0x1,%esi
  sub    $0x1,%ebx
  cmp    %r9b,0x0(%rbp)
  je     L142
  jmp    L57
  nopw   0x0(%rax,%rax,1)
L270:
  lea    0x20(%rsp),%r12
  xor    %r15d,%r15d
  mov    $0x10,%esi
  mov    %r12,%rax
  test   %ebx,%ebx
  je     L279
  lea    0x20(%rsp),%r12
  cmpl   $0x1,0x10(%rsp)
  mov    %r12,%rax
  je     L63
  jmp    L311
  nopl   0x0(%rax)
L236:
  mov    %edx,%r9d
  test   %ebx,%ebx
  je     L282
  cmp    $0xf,%r15d
  je     L282
  mov    %esi,%edx
L63:
  mov    %r9b,(%rax)
  mov    %rbp,%r9
  movzbl 0x1(%rbp),%esi
  add    $0x1,%rax
  mov    %r15d,%edi
  add    $0x1,%rbp
  mov    %ebx,%r10d
  add    $0x1,%r15d
  sub    $0x1,%ebx
  cmp    %sil,%dl
  jne    L236
L123:
  cmp    $0xf,%r15d
  je     L116
  test   %ebx,%ebx
  je     L116
  mov    %edi,%esi
  mov    %edi,%r15d
  mov    %r10d,%ebx
  mov    %r9,%rbp
  or     $0x10,%esi
  nopl   0x0(%rax,%rax,1)
L252:
  mov    %r8,%rdx
  mov    $0x5,%edi
  mov    %r12,%r14
  call   <intobyte@plt>
  mov    %rax,%r8
  nopl   0x0(%rax,%rax,1)
L113:
  movzbl (%r14),%esi
  mov    %r8,%rdx
  mov    %r13d,%edi
  add    $0x1,%r14
  call   <intobyte@plt>
  mov    %rax,%r8
  mov    %r12d,%eax
  sub    %r14d,%eax
  add    %r15d,%eax
  jns    L113
  jmp    L59
  xchg   %ax,%ax
L239:
  mov    %edx,%r9d
  test   %ebx,%ebx
  je     L282
  cmp    $0xf,%r15d
  je     L282
  mov    %esi,%edx
L311:
  mov    %r9b,(%rax)
  mov    %rbp,%r9
  add    0x8(%rsp),%rbp
  add    $0x1,%rax
  movzbl 0x0(%rbp),%esi
  mov    %r15d,%edi
  mov    %ebx,%r10d
  add    $0x1,%r15d
  sub    $0x1,%ebx
  cmp    %dl,%sil
  jne    L239
  jmp    L123
  nopl   0x0(%rax)
L306:
  lea    0x20(%rsp),%r12
  xor    %r15d,%r15d
  mov    %r12,%rax
L217:
  mov    %r15d,%esi
  or     $0x10,%esi
L279:
  mov    %r9b,(%rax)
  jmp    L252
  nopl   0x0(%rax)
L282:
  mov    %r15d,%esi
  or     $0x10,%esi
  test   %ebx,%ebx
  je     L145
  cmp    $0xf,%r15d
  jne    L252
L145:
  mov    %edx,%r9d
  mov    %r9b,(%rax)
  jmp    L252
L268:
  call   <__stack_chk_fail@plt>
L116:
  mov    %edx,%r9d
  jmp    L217
```

assistant: ```c
unsigned char *packline(unsigned char *in, unsigned char *out, int len, int size, int dir) {
  unsigned char differ[16], *d_ptr, *out0, last;
  int counter;
  out0 = out++;
  *out0 = 0;
  intobyte(0, 0, 0);
  while (len) {
    last = *in;
    in += dir;
    --len;
    counter = 0;
    if ((last == *in) && len) {
      do {
        ++counter;
        in += dir;
        --len;
      } while (last == *in && len && counter != 15);
      out = intobyte(5, counter, out);
      out = intobyte(size, last, out);
    } else {
      d_ptr = differ;
      while (last != *in && len && counter != 15) {
        *d_ptr++ = last;
        ++counter;
        last = *in;
        in += dir;
        --len;
      }
      if (!len || counter == 15)
        *d_ptr = last;
      else if (last == *in) {
        --counter;
        in -= dir;
        ++len;
      }
      out = intobyte(5, counter | 0x10, out);
      d_ptr = differ;
      do {
        out = intobyte(size, *d_ptr++, out);
      } while (--counter >= 0);
    }
  }
  out = intobyte(8, 0, out);
  *out0 = out - out0;
  return out;
}
```