user: 下面的汇编指令对应的C源代码是什么：

```asm
<parse_string>:
  endbr64
  test   %rsi,%rsi
  je     L48
  push   %r15
  push   %r14
  push   %r13
  push   %r12
  mov    %rsi,%r12
  push   %rbp
  push   %rbx
  sub    $0x8,%rsp
  test   %rdi,%rdi
  je     L79
  mov    %rdx,%rbp
  test   %rdx,%rdx
  je     L79
  mov    (%rdx),%r15
  mov    %rcx,%r13
  test   %r15,%r15
  jne    L187
  mov    %rdi,%r15
  mov    %rdi,(%rdx)
  movsbl (%r15),%edi
  test   %dil,%dil
  je     L118
  nopl   (%rax)
L171:
  call   <isspace@plt>
  test   %rax,%rax
  je     L121
  add    $0x1,%r15
L187:
  movsbl (%r15),%edi
  test   %dil,%dil
  jne    L171
L118:
  mov    %r15,0x0(%rbp)
  xor    %eax,%eax
  mov    %r15,(%r12)
  add    $0x8,%rsp
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
L121:
  movzbl (%r15),%eax
  test   %al,%al
  je     L118
  movsbl 0x1(%r15),%edi
  lea    0x1(%r15),%r14
  mov    %r14,%rbx
  test   %dil,%dil
  je     L177
  nopl   (%rax)
L102:
  cmp    $0x22,%al
  je     L91
L133:
  cmp    $0x27,%al
  je     L91
  call   <isspace@plt>
  test   %rax,%rax
  jne    L25
  movsbl 0x1(%rbx),%edi
  add    $0x1,%rbx
  test   %dil,%dil
  je     L177
  movzbl (%r15),%eax
  cmp    $0x22,%al
  jne    L133
  nop
L91:
  movzbl 0x1(%rbx),%edx
  cmp    %al,%dil
  je     L178
  test   %dl,%dl
  je     L165
L3:
  add    $0x1,%rbx
  movsbl %dl,%edi
  jmp    L102
  nopw   0x0(%rax,%rax,1)
L178:
  movsbl %dl,%edi
  call   <isspace@plt>
  test   %rax,%rax
  jne    L92
  movzbl 0x1(%rbx),%edx
  test   %dl,%dl
  je     L92
  movzbl (%r15),%eax
  jmp    L3
  nopl   0x0(%rax,%rax,1)
L79:
  mov    D52(%rip),%rax
  movq   $0x0,(%r12)
  mov    (%rax),%edx
  mov    D44(%rip),%rax
  mov    %edx,(%rax)
  mov    $0xffffffff,%eax
L201:
  add    $0x8,%rsp
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
L25:
  movb   $0x0,(%rbx)
  xor    %edi,%edi
  add    $0x1,%rbx
L177:
  mov    %r15,(%r12)
  mov    $0x1,%eax
  mov    %rbx,0x0(%rbp)
  test   %r13,%r13
  je     L201
  mov    %dil,0x0(%r13)
  add    $0x8,%rsp
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
  nopl   0x0(%rax)
L48:
  mov    D52(%rip),%rax
  mov    (%rax),%edx
  mov    D44(%rip),%rax
  mov    %edx,(%rax)
  mov    $0xffffffff,%eax
  ret
L165:
  mov    D43(%rip),%rax
  add    $0x1,%rbx
  mov    (%rax),%edx
  mov    D44(%rip),%rax
  mov    %edx,(%rax)
  mov    $0xffffffff,%eax
  mov    %r15,(%r12)
  mov    %rbx,0x0(%rbp)
  add    $0x8,%rsp
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
L92:
  movzbl (%r15),%edi
  add    $0x1,%rbx
  movb   $0x0,-0x1(%rbx)
  mov    %r14,%r15
  jmp    L177
```

assistant: ```c
int parse_string(char *src, char **dst_p, char **ptr_p, char *quote_p) {
  char *p;
  char *q;
  char c = 0;
  if (!dst_p) {
    errno = EINVAL;
    return (-1);
  }
  if (!src || !ptr_p) {
    *dst_p = NULL;
    errno = EINVAL;
    return (-1);
  }
  if (*ptr_p == NULL) {
    *ptr_p = src;
  }
  for (p = *ptr_p; *p && isspace((int)*p); p++) {
    ;
  }
  if (*p == '\0') {
    *dst_p = *ptr_p = p;
    return (0);
  }
  for (q = p + 1; *q; q++) {
    if ((*p == '"') || (*p == '\'')) {
      if ((*q == *p) && (isspace((int)*(q + 1)) || (*(q + 1) == '\0'))) {
        c = *p++;
        *q++ = '\0';
        break;
      } else if (*(q + 1) == '\0') {
        errno = EIO;
        *dst_p = p;
        *ptr_p = q + 1;
        return (-1);
      }
    } else if (isspace((int)*q)) {
      *q++ = '\0';
      break;
    }
  }
  *dst_p = p;
  *ptr_p = q;
  if (quote_p) {
    *quote_p = c;
  }
  return (1);
}
```