user: 请显示与下面列出的汇编代码相匹配的C语言实现：

```asm
<__dn_expand>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  mov    %rdi,-0x18(%rbp)
  mov    %rsi,-0x20(%rbp)
  mov    %rdx,-0x28(%rbp)
  mov    %rcx,-0x30(%rbp)
  mov    %r8d,-0x34(%rbp)
  mov    -0x28(%rbp),%rax
  mov    %rax,-0x8(%rbp)
  movl   $0xffffffff,-0x10(%rbp)
  cmpl   $0x100,-0x34(%rbp)
  jle    L169
  movl   $0x100,-0x34(%rbp)
L169:
  mov    -0x8(%rbp),%rax
  cmp    -0x20(%rbp),%rax
  je     L161
  mov    -0x8(%rbp),%rax
  movzbl (%rax),%eax
  test   %al,%al
  jne    L5
L161:
  mov    $0xffffffff,%eax
  jmp    L147
L5:
  mov    -0x8(%rbp),%rax
  movzbl (%rax),%eax
  movzbl %al,%eax
  and    $0xc0,%eax
  test   %eax,%eax
  je     L14
  mov    -0x8(%rbp),%rax
  add    $0x1,%rax
  cmp    %rax,-0x20(%rbp)
  jne    L123
  mov    $0xffffffff,%eax
  jmp    L147
L123:
  mov    -0x8(%rbp),%rax
  movzbl (%rax),%eax
  movzbl %al,%eax
  shl    $0x8,%eax
  and    $0x3f00,%eax
  mov    %eax,%edx
  mov    -0x8(%rbp),%rax
  add    $0x1,%rax
  movzbl (%rax),%eax
  movzbl %al,%eax
  or     %edx,%eax
  mov    %eax,-0xc(%rbp)
  cmpl   $0x0,-0x10(%rbp)
  jns    L47
  mov    -0x8(%rbp),%rax
  add    $0x2,%rax
  sub    -0x28(%rbp),%rax
  mov    %eax,-0x10(%rbp)
L47:
  mov    -0xc(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x20(%rbp),%rax
  sub    -0x18(%rbp),%rax
  cmp    %rax,%rdx
  jl     L16
  mov    $0xffffffff,%eax
  jmp    L147
L16:
  mov    -0xc(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x18(%rbp),%rax
  add    %rdx,%rax
  mov    %rax,-0x8(%rbp)
  jmp    L5
L14:
  mov    -0x8(%rbp),%rax
  movzbl (%rax),%eax
  test   %al,%al
  je     L190
  mov    -0x8(%rbp),%rax
  movzbl (%rax),%eax
  movzbl %al,%eax
  add    $0x1,%eax
  mov    %eax,-0xc(%rbp)
  mov    -0xc(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x20(%rbp),%rax
  sub    -0x8(%rbp),%rax
  cmp    %rax,%rdx
  jge    L38
  mov    -0xc(%rbp),%eax
  cmp    -0x34(%rbp),%eax
  jle    L71
L38:
  mov    $0xffffffff,%eax
  jmp    L147
L144:
  addq   $0x1,-0x8(%rbp)
  mov    -0x8(%rbp),%rax
  movzbl (%rax),%ecx
  mov    -0x30(%rbp),%rax
  lea    0x1(%rax),%rdx
  mov    %rdx,-0x30(%rbp)
  mov    %ecx,%edx
  mov    %dl,(%rax)
L71:
  subl   $0x1,-0xc(%rbp)
  cmpl   $0x0,-0xc(%rbp)
  jne    L144
  addq   $0x1,-0x8(%rbp)
  mov    -0x8(%rbp),%rax
  movzbl (%rax),%eax
  test   %al,%al
  je     L121
  mov    $0x2e,%ecx
  jmp    L134
L121:
  mov    $0x0,%ecx
L134:
  mov    -0x30(%rbp),%rax
  lea    0x1(%rax),%rdx
  mov    %rdx,-0x30(%rbp)
  mov    %cl,(%rax)
  jmp    L5
L190:
  cmpl   $0x0,-0x10(%rbp)
  jns    L101
  mov    -0x8(%rbp),%rax
  add    $0x1,%rax
  sub    -0x28(%rbp),%rax
  mov    %eax,-0x10(%rbp)
L101:
  mov    -0x10(%rbp),%eax
L147:
  pop    %rbp
  ret
```

assistant: ```c
int __dn_expand(const unsigned char *base, const unsigned char *end, const unsigned char *src, char *dest, int space) {
  const unsigned char *p = src;
  int len = -1, j;
  if (space > 256)
    space = 256;
  if (p == end || !*p)
    return -1;
  for (;;) {
    if (*p & 0xc0) {
      if (p + 1 == end)
        return -1;
      j = ((p[0] & 0x3f) << 8) | p[1];
      if (len < 0)
        len = p + 2 - src;
      if (j >= end - base)
        return -1;
      p = base + j;
    } else if (*p) {
      j = *p + 1;
      if (j >= end - p || j > space)
        return -1;
      while (--j)
        *dest++ = *++p;
      *dest++ = *++p ? '.' : 0;
    } else {
      if (len < 0)
        len = p + 1 - src;
      return len;
    }
  }
}
```