user: Please show me the C implementation that matches the assembly code listed below:

```asm
<string_decode_base64>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  sub    $0xa0,%rsp
  mov    %rdi,-0x98(%rbp)
  mov    %rsi,-0xa0(%rbp)
  mov    %fs:0x28,%rax
  mov    %rax,-0x8(%rbp)
  xor    %eax,%eax
  movabs $0x7473727d2424247c,%rax
  movabs $0x247b7a7978777675,%rdx
  mov    %rax,-0x60(%rbp)
  mov    %rdx,-0x58(%rbp)
  movabs $0x3f3e242424242424,%rax
  movabs $0x4746454443424140,%rdx
  mov    %rax,-0x50(%rbp)
  mov    %rdx,-0x48(%rbp)
  movabs $0x4f4e4d4c4b4a4948,%rax
  movabs $0x5756555453525150,%rdx
  mov    %rax,-0x40(%rbp)
  mov    %rdx,-0x38(%rbp)
  movabs $0x5958242424242424,%rax
  movabs $0x61605f5e5d5c5b5a,%rdx
  mov    %rax,-0x30(%rbp)
  mov    %rdx,-0x28(%rbp)
  movabs $0x6968676665646362,%rax
  movabs $0x71706f6e6d6c6b6a,%rdx
  mov    %rax,-0x20(%rbp)
  mov    %rdx,-0x18(%rbp)
  movb   $0x0,-0x10(%rbp)
  mov    -0x98(%rbp),%rax
  mov    %rax,-0x78(%rbp)
  mov    -0xa0(%rbp),%rax
  mov    %rax,-0x70(%rbp)
  mov    -0x70(%rbp),%rax
  movb   $0x0,(%rax)
  movl   $0x0,-0x80(%rbp)
  jmp    L172
L85:
  movl   $0x0,-0x84(%rbp)
  movl   $0x0,-0x7c(%rbp)
  jmp    L65
L178:
  mov    -0x7c(%rbp),%eax
  cltq
  movb   $0x0,-0x64(%rbp,%rax,1)
  addl   $0x1,-0x7c(%rbp)
L65:
  cmpl   $0x3,-0x7c(%rbp)
  jle    L178
  movl   $0x0,-0x7c(%rbp)
  jmp    L5
L193:
  movb   $0x0,-0x85(%rbp)
  jmp    L76
L57:
  mov    -0x78(%rbp),%rax
  movzbl (%rax),%eax
  mov    %al,-0x85(%rbp)
  addq   $0x1,-0x78(%rbp)
  cmpb   $0x2a,-0x85(%rbp)
  jbe    L106
  cmpb   $0x7a,-0x85(%rbp)
  ja     L106
  movzbl -0x85(%rbp),%eax
  sub    $0x2b,%eax
  cltq
  movzbl -0x60(%rbp,%rax,1),%eax
  jmp    L103
L106:
  mov    $0x0,%eax
L103:
  mov    %al,-0x85(%rbp)
  cmpb   $0x0,-0x85(%rbp)
  je     L76
  cmpb   $0x24,-0x85(%rbp)
  je     L17
  movzbl -0x85(%rbp),%eax
  sub    $0x3d,%eax
  jmp    L104
L17:
  mov    $0x0,%eax
L104:
  mov    %al,-0x85(%rbp)
L76:
  mov    -0x78(%rbp),%rax
  movzbl (%rax),%eax
  test   %al,%al
  je     L67
  cmpb   $0x0,-0x85(%rbp)
  je     L57
L67:
  mov    -0x78(%rbp),%rax
  movzbl (%rax),%eax
  test   %al,%al
  je     L190
  addl   $0x1,-0x84(%rbp)
  cmpb   $0x0,-0x85(%rbp)
  je     L195
  movzbl -0x85(%rbp),%eax
  lea    -0x1(%rax),%edx
  mov    -0x7c(%rbp),%eax
  cltq
  mov    %dl,-0x64(%rbp,%rax,1)
  jmp    L195
L190:
  mov    -0x7c(%rbp),%eax
  cltq
  movb   $0x0,-0x64(%rbp,%rax,1)
  jmp    L128
L195:
  addl   $0x1,-0x7c(%rbp)
L5:
  cmpl   $0x3,-0x7c(%rbp)
  jle    L193
L128:
  cmpl   $0x0,-0x84(%rbp)
  je     L172
  lea    -0x67(%rbp),%rdx
  lea    -0x64(%rbp),%rax
  mov    %rdx,%rsi
  mov    %rax,%rdi
  call   <string_convbase64_6x4_to_8x3@plt>
  movl   $0x0,-0x7c(%rbp)
  jmp    L141
L43:
  mov    -0x7c(%rbp),%eax
  cltq
  movzbl -0x67(%rbp,%rax,1),%eax
  mov    %eax,%edx
  mov    -0x70(%rbp),%rax
  mov    %dl,(%rax)
  addq   $0x1,-0x70(%rbp)
  addl   $0x1,-0x80(%rbp)
  addl   $0x1,-0x7c(%rbp)
L141:
  mov    -0x84(%rbp),%eax
  sub    $0x1,%eax
  cmp    %eax,-0x7c(%rbp)
  jl     L43
L172:
  cmpq   $0x0,-0x78(%rbp)
  je     L36
  mov    -0x78(%rbp),%rax
  movzbl (%rax),%eax
  test   %al,%al
  jne    L85
L36:
  mov    -0x70(%rbp),%rax
  movb   $0x0,(%rax)
  mov    -0x80(%rbp),%eax
  mov    -0x8(%rbp),%rdx
  sub    %fs:0x28,%rdx
  je     L88
  call   <__stack_chk_fail@plt>
L88:
  leave
  ret
```

assistant: ```c
int string_decode_base64(const char *from, char *to) {
  const char *ptr_from;
  int length, to_length, i;
  char *ptr_to;
  unsigned char c, in[4], out[3];
  unsigned char base64_table[] = "|$$$}rstuvwxyz{$$$$$$$>?"
                                 "@ABCDEFGHIJKLMNOPQRSTUVW$$$$$$XYZ[\\]^_`abcdefghijklmnopq";
  ptr_from = from;
  ptr_to = to;
  ptr_to[0] = '\0';
  to_length = 0;
  while (ptr_from && ptr_from[0]) {
    length = 0;
    for (i = 0; i < 4; i++) {
      in[i] = 0;
    }
    for (i = 0; i < 4; i++) {
      c = 0;
      while (ptr_from[0] && (c == 0)) {
        c = (unsigned char)ptr_from[0];
        ptr_from++;
        c = ((c < 43) || (c > 122)) ? 0 : base64_table[c - 43];
        if (c)
          c = (c == '$') ? 0 : c - 61;
      }
      if (ptr_from[0]) {
        length++;
        if (c)
          in[i] = c - 1;
      } else {
        in[i] = '\0';
        break;
      }
    }
    if (length) {
      string_convbase64_6x4_to_8x3(in, out);
      for (i = 0; i < length - 1; i++) {
        ptr_to[0] = out[i];
        ptr_to++;
        to_length++;
      }
    }
  }
  ptr_to[0] = '\0';
  return to_length;
}
```