user: What is the c source code of the assembly code below:

```asm
<parse_qrels_line>:
  endbr64
  push   %r15
  push   %r14
  push   %r13
  push   %r12
  push   %rbp
  push   %rbx
  sub    $0x8,%rsp
  mov    %rdi,%r13
  mov    %rsi,%rbp
  mov    %rdx,%r15
  mov    %rcx,%r14
  mov    (%rdi),%rbx
  movzbl (%rbx),%edi
  cmp    $0xa,%dil
  je     L309
L280:
  movsbl %dil,%edi
  call   <isspace@plt>
  test   %rax,%rax
  je     L309
  add    $0x1,%rbx
  movzbl (%rbx),%edi
  cmp    $0xa,%dil
  jne    L280
L309:
  mov    %rbx,0x0(%rbp)
L50:
  movsbl (%rbx),%edi
  call   <isspace@plt>
  test   %rax,%rax
  jne    L163
  add    $0x1,%rbx
  jmp    L50
L163:
  cmpb   $0xa,(%rbx)
  je     L319
  lea    0x1(%rbx),%r12
  movb   $0x0,(%rbx)
  movzbl 0x1(%rbx),%edi
  cmp    $0xa,%dil
  je     L101
L335:
  movsbl %dil,%edi
  call   <isspace@plt>
  test   %rax,%rax
  je     L101
  add    $0x1,%r12
  movzbl (%r12),%edi
  cmp    $0xa,%dil
  jne    L335
  jmp    L101
L353:
  add    $0x1,%r12
L101:
  movsbl (%r12),%edi
  call   <isspace@plt>
  test   %rax,%rax
  je     L353
  cmpb   $0xa,(%r12)
  je     L242
  lea    0x1(%r12),%rbp
  movzbl 0x1(%r12),%edi
  cmp    $0xa,%dil
  je     L317
L327:
  movsbl %dil,%edi
  call   <isspace@plt>
  test   %rax,%rax
  je     L317
  add    $0x1,%rbp
  movzbl 0x0(%rbp),%edi
  cmp    $0xa,%dil
  jne    L327
L317:
  mov    %rbp,(%r15)
  jmp    L294
L205:
  add    $0x1,%rbp
L294:
  movsbl 0x0(%rbp),%edi
  call   <isspace@plt>
  test   %rax,%rax
  je     L205
  cmpb   $0xa,0x0(%rbp)
  je     L349
  lea    0x1(%rbp),%rbx
  movb   $0x0,0x0(%rbp)
  movzbl 0x1(%rbp),%edi
  cmp    $0xa,%dil
  je     L13
L119:
  movsbl %dil,%edi
  call   <isspace@plt>
  test   %rax,%rax
  je     L156
  add    $0x1,%rbx
  movzbl (%rbx),%edi
  cmp    $0xa,%dil
  jne    L119
L13:
  mov    $0xffffffff,%eax
  jmp    L121
L156:
  cmpb   $0xa,(%rbx)
  je     L346
  mov    %rbx,(%r14)
  jmp    L344
L166:
  add    $0x1,%rbx
L344:
  movsbl (%rbx),%edi
  call   <isspace@plt>
  test   %rax,%rax
  je     L166
  cmpb   $0xa,(%rbx)
  je     L315
  lea    0x1(%rbx),%rbp
  movb   $0x0,(%rbx)
  movzbl 0x1(%rbx),%edi
  cmp    $0xa,%dil
  je     L150
L343:
  movsbl %dil,%edi
  call   <isspace@plt>
  test   %rax,%rax
  je     L215
  add    $0x1,%rbp
  movzbl 0x0(%rbp),%edi
  cmp    $0xa,%dil
  jne    L343
L150:
  mov    %rbp,%rbx
L315:
  movb   $0x0,(%rbx)
  add    $0x1,%rbx
  mov    %rbx,0x0(%r13)
  mov    $0x0,%eax
L121:
  add    $0x8,%rsp
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
L215:
  cmpb   $0xa,0x0(%rbp)
  jne    L307
  mov    %rbp,%rbx
  jmp    L315
L319:
  mov    $0xffffffff,%eax
  jmp    L121
L242:
  mov    $0xffffffff,%eax
  jmp    L121
L349:
  mov    $0xffffffff,%eax
  jmp    L121
L346:
  mov    $0xffffffff,%eax
  jmp    L121
L307:
  mov    $0xffffffff,%eax
  jmp    L121
```

assistant: ```c
int parse_qrels_line(char **start_ptr, char **qid_ptr, char **docno_ptr, char **rel_ptr) {
  char *ptr = *start_ptr;
  while (*ptr != '\n' && isspace(*ptr))
    ptr++;
  *qid_ptr = ptr;
  while (!isspace(*ptr))
    ptr++;
  if (*ptr == '\n')
    return (-1);
  *ptr++ = '\0';
  while (*ptr != '\n' && isspace(*ptr))
    ptr++;
  while (!isspace(*ptr))
    ptr++;
  if (*ptr == '\n')
    return (-1);
  ptr++;
  while (*ptr != '\n' && isspace(*ptr))
    ptr++;
  *docno_ptr = ptr;
  while (!isspace(*ptr))
    ptr++;
  if (*ptr == '\n')
    return (-1);
  *ptr++ = '\0';
  while (*ptr != '\n' && isspace(*ptr))
    ptr++;
  if (*ptr == '\n')
    return (-1);
  *rel_ptr = ptr;
  while (!isspace(*ptr))
    ptr++;
  if (*ptr != '\n') {
    *ptr++ = '\0';
    while (*ptr != '\n' && isspace(*ptr))
      ptr++;
    if (*ptr != '\n')
      return (-1);
  }
  *ptr++ = '\0';
  *start_ptr = ptr;
  return (0);
}
```