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

```asm
<read_string>:
  endbr64
  push   %r14
  push   %r13
  push   %r12
  push   %rbp
  push   %rbx
  sub    $0x10,%rsp
  mov    %rdi,%r12
  mov    %esi,%r13d
  mov    %fs:0x28,%rax
  mov    %rax,0x8(%rsp)
  xor    %eax,%eax
  movb   $0x0,(%rdi)
  mov    $0x0,%ebx
  lea    0x7(%rsp),%rbp
  jmp    L139
L103:
  movb   $0x8,0x7(%rsp)
  mov    $0x1,%esi
  mov    %rbp,%rdi
  call   <sio_write@plt>
  sub    $0x1,%ebx
  mov    %ebx,%esi
  mov    %r12,%rdi
  call   <flush_line@plt>
  mov    $0x1,%esi
  mov    %rbp,%rdi
  call   <sio_write@plt>
  jmp    L139
L23:
  mov    %ebx,%eax
  cmpb   $0x0,(%r12,%rax,1)
  jne    L87
L139:
  mov    $0x1,%esi
  mov    %rbp,%rdi
  call   <sio_read@plt>
  test   %eax,%eax
  je     L139
  movzbl 0x7(%rsp),%edx
  cmp    $0xd,%dl
  je     L25
  test   %ebx,%ebx
  setne  %al
  cmp    $0x2,%dl
  jne    L152
  test   %al,%al
  jne    L103
L152:
  cmp    $0x6,%dl
  je     L23
  cmp    $0x8,%dl
  jne    L165
  test   %al,%al
  jne    L163
L165:
  cmp    $0x7f,%dl
  je     L164
  cmp    $0x1f,%dl
  jbe    L139
  cmp    %ebx,%r13d
  ja     L39
  cmp    $0xffffffff,%r13d
  jne    L139
L39:
  movzbl %dl,%edx
  mov    %ebx,%esi
  mov    %r12,%rdi
  call   <insert_char@plt>
  lea    0x1(%rbx),%r14d
  mov    %ebx,%esi
  mov    %r12,%rdi
  call   <flush_line@plt>
  mov    %r14d,%ebx
  jmp    L139
L87:
  lea    0x1(%rbx),%r14d
  mov    %ebx,%esi
  mov    %r12,%rdi
  call   <flush_line@plt>
  mov    $0x1,%esi
  mov    %rbp,%rdi
  call   <sio_write@plt>
  mov    %r14d,%ebx
  jmp    L139
L163:
  mov    %ebx,%esi
  mov    %r12,%rdi
  call   <delete_char@plt>
  movb   $0x8,0x7(%rsp)
  mov    $0x1,%esi
  mov    %rbp,%rdi
  call   <sio_write@plt>
  sub    $0x1,%ebx
  mov    %ebx,%esi
  mov    %r12,%rdi
  call   <flush_line@plt>
  mov    $0x1,%esi
  mov    %rbp,%rdi
  call   <sio_write@plt>
  jmp    L139
L164:
  lea    0x1(%rbx),%esi
  mov    %r12,%rdi
  call   <delete_char@plt>
  mov    %ebx,%esi
  mov    %r12,%rdi
  call   <flush_line@plt>
  movb   $0x8,0x7(%rsp)
  mov    $0x1,%esi
  mov    %rbp,%rdi
  call   <sio_write@plt>
  jmp    L139
L25:
  mov    %r12,%rdi
  call   <strlen@plt>
  mov    0x8(%rsp),%rdx
  sub    %fs:0x28,%rdx
  jne    L136
  add    $0x10,%rsp
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  ret
L136:
  call   <__stack_chk_fail@plt>
```

assistant: ```c
int read_string(char *data, int size) {
  unsigned int n, index;
  unsigned char c;
  index = 0;
  data[index] = 0;
  while (1) {
    n = sio_read(&c, 1);
    if (n < 1)
      continue;
    if (c == '\r') {
      break;
    }
    if (c == 2 && index > 0) {
      c = 8;
      sio_write(&c, 1);
      flush_line(data, --index);
      sio_write(&c, 1);
    } else if (c == 6 && data[index] != 0) {
      flush_line(data, index++);
      sio_write(&c, 1);
    } else if (c == 8 && index > 0) {
      delete_char(data, index);
      c = 8;
      sio_write(&c, 1);
      flush_line(data, --index);
      sio_write(&c, 1);
    } else if (c == 0x7f) {
      delete_char(data, index + 1);
      flush_line(data, index);
      c = 8;
      sio_write(&c, 1);
    } else if (c >= 0x20 && ((index < size) || size == -1)) {
      insert_char(data, index, c);
      flush_line(data, index++);
    }
  }
  n = strlen(data);
  return n;
}
```