user: 请从给定的汇编指令推导出C源代码：

```asm
<str_unescape>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  sub    $0x30,%rsp
  mov    %rdi,-0x28(%rbp)
  mov    -0x28(%rbp),%rax
  mov    %rax,-0x20(%rbp)
  mov    -0x28(%rbp),%rax
  mov    %rax,%rdi
  call   <strlen@plt>
  add    $0x1,%rax
  mov    $0x1,%esi
  mov    %rax,%rdi
  call   <calloc@plt>
  mov    %rax,-0x10(%rbp)
  mov    -0x10(%rbp),%rax
  mov    %rax,-0x18(%rbp)
  jmp    L113
L59:
  mov    -0x20(%rbp),%rax
  movzbl (%rax),%eax
  cmp    $0x5c,%al
  jne    L23
  addq   $0x1,-0x20(%rbp)
  mov    -0x20(%rbp),%rax
  movzbl (%rax),%eax
  movsbl %al,%eax
  sub    $0x30,%eax
  cmp    $0x46,%eax
  ja     L97
  mov    %eax,%eax
  lea    0x0(,%rax,4),%rdx
  lea    D1(%rip),%rax
  mov    (%rdx,%rax,1),%eax
  cltq
  lea    D1(%rip),%rdx
  add    %rdx,%rax
  notrack jmp *%rax
  mov    -0x18(%rbp),%rax
  movb   $0x0,(%rax)
  mov    -0x20(%rbp),%rax
  mov    %rax,-0x8(%rbp)
  jmp    L9
L28:
  mov    -0x18(%rbp),%rax
  movzbl (%rax),%eax
  lea    0x0(,%rax,8),%edx
  mov    -0x20(%rbp),%rax
  movzbl (%rax),%eax
  add    %edx,%eax
  sub    $0x30,%eax
  mov    %eax,%edx
  mov    -0x18(%rbp),%rax
  mov    %dl,(%rax)
  addq   $0x1,-0x20(%rbp)
L9:
  mov    -0x8(%rbp),%rax
  add    $0x3,%rax
  cmp    %rax,-0x20(%rbp)
  jae    L164
  mov    -0x20(%rbp),%rax
  movzbl (%rax),%eax
  cmp    $0x2f,%al
  jle    L164
  mov    -0x20(%rbp),%rax
  movzbl (%rax),%eax
  cmp    $0x37,%al
  jle    L28
L164:
  addq   $0x1,-0x18(%rbp)
  subq   $0x1,-0x20(%rbp)
  jmp    L43
  mov    -0x18(%rbp),%rax
  lea    0x1(%rax),%rdx
  mov    %rdx,-0x18(%rbp)
  movb   $0x7,(%rax)
  jmp    L43
  mov    -0x18(%rbp),%rax
  lea    0x1(%rax),%rdx
  mov    %rdx,-0x18(%rbp)
  movb   $0x8,(%rax)
  jmp    L43
  mov    -0x18(%rbp),%rax
  lea    0x1(%rax),%rdx
  mov    %rdx,-0x18(%rbp)
  movb   $0xc,(%rax)
  jmp    L43
  mov    -0x18(%rbp),%rax
  lea    0x1(%rax),%rdx
  mov    %rdx,-0x18(%rbp)
  movb   $0xa,(%rax)
  jmp    L43
  mov    -0x18(%rbp),%rax
  lea    0x1(%rax),%rdx
  mov    %rdx,-0x18(%rbp)
  movb   $0xd,(%rax)
  jmp    L43
  mov    -0x18(%rbp),%rax
  lea    0x1(%rax),%rdx
  mov    %rdx,-0x18(%rbp)
  movb   $0x9,(%rax)
  jmp    L43
  mov    -0x18(%rbp),%rax
  lea    0x1(%rax),%rdx
  mov    %rdx,-0x18(%rbp)
  movb   $0xb,(%rax)
  jmp    L43
L97:
  mov    -0x18(%rbp),%rax
  lea    0x1(%rax),%rdx
  mov    %rdx,-0x18(%rbp)
  mov    -0x20(%rbp),%rdx
  movzbl (%rdx),%edx
  mov    %dl,(%rax)
  jmp    L43
L23:
  mov    -0x18(%rbp),%rax
  lea    0x1(%rax),%rdx
  mov    %rdx,-0x18(%rbp)
  mov    -0x20(%rbp),%rdx
  movzbl (%rdx),%edx
  mov    %dl,(%rax)
L43:
  addq   $0x1,-0x20(%rbp)
L113:
  mov    -0x20(%rbp),%rax
  movzbl (%rax),%eax
  test   %al,%al
  jne    L59
  mov    -0x18(%rbp),%rax
  movb   $0x0,(%rax)
  mov    -0x10(%rbp),%rax
  leave
  ret
```

assistant: ```c
char *str_unescape(const char *source) {
  const char *p = source;
  const char *octal;
  char *dest = calloc(strlen(source) + 1, sizeof(char));
  char *q = dest;
  while (*p) {
    if (*p == '\\') {
      p++;
      switch (*p) {
      case '0' ... '7':
        *q = 0;
        octal = p;
        while ((p < octal + 3) && (*p >= '0') && (*p <= '7')) {
          *q = (*q * 8) + (*p - '0');
          p++;
        }
        q++;
        p--;
        break;
      case 'a':
        *q++ = '\a';
        break;
      case 'b':
        *q++ = '\b';
        break;
      case 'f':
        *q++ = '\f';
        break;
      case 'n':
        *q++ = '\n';
        break;
      case 'r':
        *q++ = '\r';
        break;
      case 't':
        *q++ = '\t';
        break;
      case 'v':
        *q++ = '\v';
        break;
      default:
        *q++ = *p;
        break;
      }
    } else {
      *q++ = *p;
    }
    p++;
  }
  *q = 0;
  return dest;
}
```