user: What would the C source look like for the assembly code provided here?

```asm
<inet_network>:
  endbr64
  push   %r15
  mov    %rdi,%r15
  push   %r14
  push   %r13
  push   %r12
  mov    $0xa,%r12d
  push   %rbp
  push   %rbx
  sub    $0x28,%rsp
  mov    %fs:0x28,%rax
  mov    %rax,0x18(%rsp)
  xor    %eax,%eax
  movzbl (%r15),%eax
  mov    %rsp,%r14
  mov    %r14,%r13
  cmp    $0x30,%al
  jne    L70
L221:
  movzbl 0x1(%r15),%eax
  mov    $0x8,%r12d
  add    $0x1,%r15
L70:
  mov    %eax,%edx
  and    $0xffffffdf,%edx
  cmp    $0x58,%dl
  jne    L161
L168:
  movsbl 0x1(%r15),%ebp
  test   %bpl,%bpl
  je     L215
  lea    0x2(%r15),%r12
  xor    %ebx,%ebx
L193:
  mov    %ebp,%edi
  lea    -0x1(%r12),%r15
  call   <isdigit@plt>
  test   %rax,%rax
  jne    L58
  mov    %ebp,%edi
  call   <isxdigit@plt>
  test   %rax,%rax
  jne    L98
L44:
  movzbl (%r15),%eax
  cmp    $0x2e,%al
  jne    L73
  lea    0x10(%rsp),%rax
  cmp    %rax,%r13
  je     L255
  movzbl 0x1(%r15),%eax
  add    $0x4,%r13
  add    $0x1,%r15
  mov    $0xa,%r12d
  mov    %ebx,-0x4(%r13)
  cmp    $0x30,%al
  je     L221
  mov    %eax,%edx
  and    $0xffffffdf,%edx
  cmp    $0x58,%dl
  je     L168
L161:
  xor    %ebx,%ebx
  test   %al,%al
  je     L92
L57:
  movsbl %al,%ebp
  mov    %ebp,%edi
  call   <isdigit@plt>
  test   %rax,%rax
  je     L44
  imul   %r12d,%ebx
  movzbl 0x1(%r15),%eax
  add    $0x1,%r15
  lea    -0x30(%rbp,%rbx,1),%ebx
  test   %al,%al
  jne    L57
  nopl   0x0(%rax,%rax,1)
L92:
  mov    %ebx,0x0(%r13)
  add    $0x4,%r13
  sub    %r14,%r13
  sar    $0x2,%r13
  cmp    $0x4,%r13d
  jg     L255
  test   %r13d,%r13d
  jle    L83
  movzbl (%rsp),%eax
  cmp    $0x1,%r13d
  je     L205
  movzbl 0x4(%rsp),%edx
  shl    $0x8,%eax
  or     %edx,%eax
  cmp    $0x2,%r13d
  je     L205
  movzbl 0x8(%rsp),%edx
  shl    $0x8,%eax
  or     %edx,%eax
  cmp    $0x4,%r13d
  jne    L205
  movzbl 0xc(%rsp),%edx
  shl    $0x8,%eax
  or     %edx,%eax
  jmp    L205
L58:
  shl    $0x4,%ebx
  lea    -0x30(%rbp,%rbx,1),%ebx
L86:
  movsbl (%r12),%ebp
  add    $0x1,%r12
  test   %bpl,%bpl
  jne    L193
  jmp    L92
  nopl   0x0(%rax,%rax,1)
L98:
  mov    %ebp,%edi
  shl    $0x4,%ebx
  lea    0xa(%rbp),%r15d
  call   <islower@plt>
  cmp    $0x1,%rax
  sbb    %eax,%eax
  and    $0xffffffe0,%eax
  add    $0x61,%eax
  sub    %eax,%r15d
  add    %r15d,%ebx
  jmp    L86
L73:
  test   %al,%al
  je     L92
  movsbl %al,%edi
  call   <isspace@plt>
  test   %eax,%eax
  jne    L92
  nopw   0x0(%rax,%rax,1)
L255:
  mov    $0xffffffff,%eax
L205:
  mov    0x18(%rsp),%rdx
  sub    %fs:0x28,%rdx
  jne    L145
  add    $0x28,%rsp
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
  nopl   0x0(%rax)
L215:
  xor    %ebx,%ebx
  jmp    L92
L83:
  xor    %eax,%eax
  jmp    L205
L145:
  call   <__stack_chk_fail@plt>
```

assistant: ```c
u_long inet_network(register char *cp) {
  register u_long val, base, n;
  register char c;
  u_long parts[4], *pp = parts;
  register int i;
again:
  val = 0;
  base = 10;
  if (*cp == '0')
    base = 8, cp++;
  if (*cp == 'x' || *cp == 'X')
    base = 16, cp++;
  while ((c = *cp) != '\0') {
    if (isdigit(c)) {
      val = (val * base) + ((u_long)c - '0');
      cp++;
      continue;
    }
    if (base == 16 && isxdigit(c)) {
      val = (val << 4) + ((u_long)c + 10 - (islower(c) ? 'a' : 'A'));
      cp++;
      continue;
    }
    break;
  }
  if (*cp == '.') {
    if (pp >= parts + 4)
      return (-1);
    *pp++ = val, cp++;
    goto again;
  }
  if (*cp && !isspace(*cp))
    return (-1);
  *pp++ = val;
  n = pp - parts;
  if (n > 4)
    return (-1);
  for (val = 0, i = 0; i < n; i++) {
    val <<= 8;
    val |= parts[i] & 0xff;
  }
  return (val);
}
```