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

```asm
<return_var_plus_index>:
  endbr64
  push   %r12
  push   %rbp
  mov    %esi,%ebp
  push   %rbx
  mov    %rdi,%rbx
  mov    $0x28,%edi
  sub    $0x30,%rsp
  mov    %fs:0x28,%rax
  mov    %rax,0x28(%rsp)
  xor    %eax,%eax
  call   <malloc@plt>
  mov    %rax,%r12
  test   %ebp,%ebp
  js     L200
  movzbl (%rbx),%eax
  test   %al,%al
  je     L200
  test   $0xdf,%al
  je     L49
  mov    %al,(%r12)
  movzbl 0x1(%rbx),%edx
  lea    0x1(%r12),%rax
  test   $0xdf,%dl
  je     L243
  mov    %dl,0x1(%r12)
  movzbl 0x2(%rbx),%edx
  lea    0x2(%r12),%rax
  test   $0xdf,%dl
  je     L262
  mov    %dl,0x2(%r12)
  movzbl 0x3(%rbx),%edx
  lea    0x3(%r12),%rax
  test   $0xdf,%dl
  je     L348
  mov    %dl,0x3(%r12)
  movzbl 0x4(%rbx),%edx
  lea    0x4(%r12),%rax
  test   $0xdf,%dl
  je     L184
  mov    %dl,0x4(%r12)
  movzbl 0x5(%rbx),%edx
  lea    0x5(%r12),%rax
  test   $0xdf,%dl
  je     L252
  mov    %dl,0x5(%r12)
  movzbl 0x6(%rbx),%edx
  lea    0x6(%r12),%rax
  test   $0xdf,%dl
  je     L400
  mov    %dl,0x6(%r12)
  movzbl 0x7(%rbx),%edx
  lea    0x7(%r12),%rax
  test   $0xdf,%dl
  je     L187
  mov    %dl,0x7(%r12)
  movzbl 0x8(%rbx),%edx
  lea    0x8(%r12),%rax
  test   $0xdf,%dl
  je     L405
  mov    %dl,0x8(%r12)
  movzbl 0x9(%rbx),%edx
  lea    0x9(%r12),%rax
  test   $0xdf,%dl
  je     L137
  mov    %dl,0x9(%r12)
  movzbl 0xa(%rbx),%edx
  lea    0xa(%r12),%rax
  test   $0xdf,%dl
  je     L339
  mov    %dl,0xa(%r12)
  movzbl 0xb(%rbx),%edx
  lea    0xb(%r12),%rax
  test   $0xdf,%dl
  je     L224
  mov    %dl,0xb(%r12)
  movzbl 0xc(%rbx),%edx
  lea    0xc(%r12),%rax
  test   $0xdf,%dl
  je     L114
  mov    %dl,0xc(%r12)
  movzbl 0xd(%rbx),%edx
  lea    0xd(%r12),%rax
  test   $0xdf,%dl
  je     L227
  mov    %dl,0xd(%r12)
  movzbl 0xe(%rbx),%edx
  lea    0xe(%r12),%rax
  test   $0xdf,%dl
  je     L105
  mov    %dl,0xe(%r12)
  movzbl 0xf(%rbx),%edx
  lea    0xf(%r12),%rax
  test   $0xdf,%dl
  je     L39
  mov    %dl,0xf(%r12)
  movzbl 0x10(%rbx),%eax
  test   $0xdf,%al
  je     L99
  mov    %al,0x10(%r12)
  movb   $0x0,0x11(%r12)
  jmp    L307
  nopl   0x0(%rax,%rax,1)
L200:
  movb   $0x0,(%r12)
L307:
  mov    0x28(%rsp),%rax
  sub    %fs:0x28,%rax
  jne    L86
  add    $0x30,%rsp
  mov    %r12,%rax
  pop    %rbx
  pop    %rbp
  pop    %r12
  ret
L39:
  mov    $0xf,%ebx
  nopw   0x0(%rax,%rax,1)
L241:
  movb   $0x2e,(%rax)
  sub    $0x1,%ebx
  mov    %ebp,%edx
  mov    %rsp,%rdi
  movslq %ebx,%rbx
  lea    D14(%rip),%rsi
  call   <sprintf@plt>
  lea    0x2(%r12,%rbx,1),%rdx
  lea    0x3(%r12,%rbx,1),%rax
  cmp    $0x63,%ebp
  jg     L250
L217:
  movzbl (%rsp),%ecx
  mov    %cl,(%rdx)
  cmp    $0x9,%ebp
  jle    L169
  movzbl 0x1(%rsp),%edx
  mov    %dl,(%rax)
  movb   $0x0,0x4(%r12,%rbx,1)
  jmp    L307
  nopl   0x0(%rax,%rax,1)
L250:
  movzbl (%rsp),%ecx
  mov    %cl,(%rdx)
  movzbl 0x1(%rsp),%edx
  mov    %dl,(%rax)
  movzbl 0x2(%rsp),%eax
  movb   $0x0,0x5(%r12,%rbx,1)
  mov    %al,0x4(%r12,%rbx,1)
  jmp    L307
  nopw   0x0(%rax,%rax,1)
L169:
  movb   $0x0,(%rax)
  jmp    L307
L49:
  mov    %r12,%rax
  xor    %ebx,%ebx
  jmp    L241
L243:
  mov    $0x1,%ebx
  jmp    L241
L262:
  mov    $0x2,%ebx
  jmp    L241
L348:
  mov    $0x3,%ebx
  jmp    L241
L184:
  mov    $0x4,%ebx
  jmp    L241
L252:
  mov    $0x5,%ebx
  jmp    L241
L400:
  mov    $0x6,%ebx
  jmp    L241
L187:
  mov    $0x7,%ebx
  jmp    L241
L405:
  mov    $0x8,%ebx
  jmp    L241
L137:
  mov    $0x9,%ebx
  jmp    L241
L339:
  mov    $0xa,%ebx
  jmp    L241
L224:
  mov    $0xb,%ebx
  jmp    L241
L114:
  mov    $0xc,%ebx
  jmp    L241
L227:
  mov    $0xd,%ebx
  jmp    L241
L105:
  mov    $0xe,%ebx
  jmp    L241
L99:
  movb   $0x2e,0x10(%r12)
  mov    %ebp,%edx
  mov    %rsp,%rdi
  mov    $0xf,%ebx
  lea    D14(%rip),%rsi
  call   <sprintf@plt>
  lea    0x11(%r12),%rdx
  lea    0x12(%r12),%rax
  jmp    L217
L86:
  call   <__stack_chk_fail@plt>
```

tool_calls: name: retrieve_data
arguments: label: D14
data_type: string

tool: D14: %d


assistant: ```c
char *return_var_plus_index(char *varname, int index) {
  int yo;
  char *whole;
  char num[40];
  whole = (char *)malloc(40);
  if (index < 0 || varname[0] == 0) {
    whole[0] = 0;
    return whole;
  }
  for (yo = 0; yo < 17; yo++) {
    if (varname[yo] == '\0' || varname[yo] == ' ') {
      yo -= 1;
      whole[yo + 1] = '.';
      sprintf(num, "%d\n", index);
      if (index > 99 && yo < 15) {
        whole[yo + 2] = num[0];
        whole[yo + 3] = num[1];
        whole[yo + 4] = num[2];
        whole[yo + 5] = '\0';
        return whole;
      } else if (index > 9 && yo < 16) {
        whole[yo + 2] = num[0];
        whole[yo + 3] = num[1];
        whole[yo + 4] = '\0';
        return whole;
      } else {
        whole[yo + 2] = num[0];
        whole[yo + 3] = '\0';
        return whole;
      }
    }
    whole[yo] = varname[yo];
  }
  whole[yo] = '\0';
  return whole;
}
```