user: 请将这段汇编代码片段转换成等效的C代码：

```asm
<encodeblock>:
  endbr64
  push   %r13
  push   %r12
  mov    %r8d,%r12d
  push   %rbp
  mov    %rsi,%rbp
  push   %rbx
  mov    %edx,%ebx
  sub    $0x68,%rsp
  movdqa D44(%rip),%xmm0
  mov    %fs:0x28,%rax
  mov    %rax,0x58(%rsp)
  xor    %eax,%eax
  movzbl (%rdi),%eax
  movl   $0x0,0xb(%rsp)
  movaps %xmm0,0x10(%rsp)
  movdqa D26(%rip),%xmm0
  mov    %eax,%edx
  shl    $0x4,%eax
  movb   $0x0,0xf(%rsp)
  movaps %xmm0,0x20(%rsp)
  movdqa D21(%rip),%xmm0
  shr    $0x2,%dl
  and    $0x30,%eax
  and    $0x3f,%edx
  movaps %xmm0,0x30(%rsp)
  movdqa D17(%rip),%xmm0
  movaps %xmm0,0x40(%rsp)
  movzbl 0x10(%rsp,%rdx,1),%edx
  mov    %dl,0xb(%rsp)
  movzbl 0x1(%rdi),%edx
  mov    %edx,%esi
  shr    $0x4,%sil
  movzbl %sil,%esi
  or     %esi,%eax
  cltq
  movzbl 0x10(%rsp,%rax,1),%eax
  mov    %al,0xc(%rsp)
  cmp    $0x1,%ecx
  jle    L0
  movb   $0x3d,0xd(%rsp)
  mov    $0x3d,%eax
L20:
  mov    %rbp,%rdi
  mov    %al,0xe(%rsp)
  lea    0xb(%rsp),%r13
  call   <strlen@plt>
  movslq %ebx,%rdx
  mov    %r13,%rsi
  mov    %rbp,%rdi
  sub    %rax,%rdx
  call   <strncat@plt>
  test   %r12d,%r12d
  jne    L53
L51:
  mov    0x58(%rsp),%rax
  sub    %fs:0x28,%rax
  jne    L67
  add    $0x68,%rsp
  xor    %eax,%eax
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  ret
  nop
L0:
  movzbl 0x2(%rdi),%eax
  shl    $0x2,%edx
  and    $0x3c,%edx
  mov    %eax,%esi
  shr    $0x6,%sil
  movzbl %sil,%esi
  or     %esi,%edx
  movslq %edx,%rdx
  movzbl 0x10(%rsp,%rdx,1),%edx
  mov    %dl,0xd(%rsp)
  cmp    $0x1,%ecx
  je     L29
  and    $0x3f,%eax
  movzbl 0x10(%rsp,%rax,1),%eax
  jmp    L20
  nopl   0x0(%rax)
L53:
  mov    %r13,%rsi
  lea    D12(%rip),%rdi
  xor    %eax,%eax
  call   <printf@plt>
  mov    $0xa,%edi
  call   <putchar@plt>
  jmp    L51
L67:
  call   <__stack_chk_fail@plt>
L29:
  mov    $0x3d,%eax
  jmp    L20
```

tool_calls: name: parse_data
arguments: data_label: D44
type: byte[16]
name: parse_data
arguments: data_label: D26
type: byte[16]
name: parse_data
arguments: data_label: D21
type: byte[16]
name: parse_data
arguments: data_label: D17
type: byte[16]
name: parse_data
arguments: data_label: D12
type: string

tool: {"D44": [0x41,0x42,0x43,0x44,0x45,0x46,0x47,0x48,0x49,0x4a,0x4b,0x4c,0x4d,0x4e,0x4f,0x50]}

tool: {"D26": [0x51,0x52,0x53,0x54,0x55,0x56,0x57,0x58,0x59,0x5a,0x61,0x62,0x63,0x64,0x65,0x66]}

tool: {"D21": [0x67,0x68,0x69,0x6a,0x6b,0x6c,0x6d,0x6e,0x6f,0x70,0x71,0x72,0x73,0x74,0x75,0x76]}

tool: {"D17": [0x77,0x78,0x79,0x7a,0x30,0x31,0x32,0x33,0x34,0x35,0x36,0x37,0x38,0x39,0x2d,0x5f]}

tool: D12: %s

assistant: ```c
int encodeblock(unsigned char *input, char *output, int oplen, int deltas, int debug) {
  int rc = 0;
  char encodedstr[4 + 1] = "";
  char encodingtabe[63 + 1] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
                              "abcdefghijklmnopqrstuvwxyz"
                              "0123456789"
                              "-_";
  ;
  encodedstr[0] = encodingtabe[input[0] >> 2];
  encodedstr[1] = encodingtabe[((input[0] & 0x03) << 4) | ((input[1] & 0xf0) >> 4)];
  encodedstr[2] = (deltas < 2 ? encodingtabe[((input[1] & 0x0f) << 2) | ((input[2] & 0xc0) >> 6)] : '=');
  encodedstr[3] = (deltas < 1 ? encodingtabe[input[2] & 0x3f] : '=');
  strncat(output, encodedstr, oplen - strlen(output));
  if (debug) {
    printf("%s", encodedstr);
    printf("\n");
  }
  return rc;
}
```