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

```asm
<encrypt_sku>:
  endbr64
  push   %r15
  lea    D38(%rip),%rsi
  lea    D50(%rip),%rdi
  push   %r14
  push   %r13
  push   %r12
  push   %rbp
  push   %rbx
  sub    $0x428,%rsp
  mov    %fs:0x28,%rax
  mov    %rax,0x418(%rsp)
  xor    %eax,%eax
  call   <fopen@plt>
  mov    %rax,(%rsp)
  test   %rax,%rax
  je     L11
  lea    D34(%rip),%rsi
  lea    D44(%rip),%rdi
  call   <fopen@plt>
  lea    0x10(%rsp),%r12
  mov    %rax,0x8(%rsp)
  test   %rax,%rax
  je     L23
  xchg   %ax,%ax
L31:
  mov    (%rsp),%rcx
  mov    $0x400,%edx
  mov    $0x1,%esi
  mov    %r12,%rdi
  call   <fread@plt>
  mov    %eax,%ebp
  test   %eax,%eax
  je     L77
  movsbl 0x10(%rsp),%edi
  mov    $0x8,%esi
  lea    -0x1(%rbp),%r13d
  call   <reverse_bits@plt>
  mov    %al,0x10(%rsp)
  test   %r13d,%r13d
  jle    L19
  movslq %ebp,%rdx
  lea    (%r12,%rdx,1),%r14
  nop
L45:
  movzbl -0x2(%r14),%ebx
  movzbl -0x1(%r14),%r15d
  mov    %r13d,%edi
  sub    $0x1,%r13d
  call   <fib@plt>
  sub    $0x1,%r14
  xor    %r15d,%ebx
  xor    %eax,%ebx
  mov    %bl,(%r14)
  test   %r13d,%r13d
  jne    L45
L19:
  mov    0x8(%rsp),%rcx
  mov    $0x1,%edx
  mov    %ebp,%esi
  mov    %r12,%rdi
  call   <fwrite@plt>
  jmp    L31
  nopl   (%rax)
L77:
  mov    (%rsp),%rdi
  call   <fclose@plt>
  mov    0x8(%rsp),%rdi
  call   <fclose@plt>
  mov    0x418(%rsp),%rax
  sub    %fs:0x28,%rax
  jne    L51
  add    $0x428,%rsp
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
L11:
  mov    0x418(%rsp),%rax
  sub    %fs:0x28,%rax
  jne    L51
  lea    D45(%rip),%rdi
L98:
  add    $0x428,%rsp
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  jmp    1100 <printf@plt>
L23:
  mov    0x418(%rsp),%rax
  sub    %fs:0x28,%rax
  jne    L51
  lea    D28(%rip),%rdi
  jmp    L98
L51:
  call   <__stack_chk_fail@plt>
```

tool_calls: name: disassemble_data
arguments: tag: D38
type_infered: string
name: disassemble_data
arguments: tag: D50
type_infered: string
name: disassemble_data
arguments: tag: D34
type_infered: string
name: disassemble_data
arguments: tag: D44
type_infered: string
name: disassemble_data
arguments: tag: D45
type_infered: string
name: disassemble_data
arguments: tag: D28
type_infered: string

tool: D38: r

tool: D50: sku.testout

tool: D34: w

tool: D44: sku.test17out

tool: D45: couldn't open input file sku.17


tool: D28: couldn't open output file sku.testout


assistant: ```c
void encrypt_sku(void) {
  FILE *sku17;
  FILE *skutestout;
  char sku_buffer[1024];
  int num_bytes_read;
  if ((sku17 = fopen("sku.testout", "r")) == NULL) {
    printf("couldn't open input file sku.17\n");
    return;
  }
  if ((skutestout = fopen("sku.test17out", "w")) == NULL) {
    printf("couldn't open output file sku.testout\n");
    return;
  }
  while (num_bytes_read = fread(sku_buffer, 1, 1024, sku17)) {
    int current_byte;
    sku_buffer[0] = reverse_bits(sku_buffer[0], 8);
    for (current_byte = num_bytes_read - 1; current_byte > 0; --current_byte) {
      sku_buffer[current_byte] = sku_buffer[current_byte - 1] ^ sku_buffer[current_byte] ^ (fib(current_byte) & 0xFF);
    }
    fwrite(sku_buffer, num_bytes_read, 1, skutestout);
  }
  fclose(sku17);
  fclose(skutestout);
  return;
}
```