user: 请显示与下面列出的汇编代码相匹配的C语言实现：

```asm
<digest_md5_getsubopt>:
  endbr64
  push   %r15
  push   %r14
  push   %r13
  push   %r12
  push   %rbp
  push   %rbx
  sub    $0x18,%rsp
  mov    %rdi,%r12
  mov    %rdx,%r15
  mov    (%rdi),%rdi
  movzbl (%rdi),%edx
  test   %dl,%dl
  je     L212
  mov    %rsi,%r14
  cmp    $0x2c,%dl
  je     L151
  mov    %rdi,%rbx
  mov    $0x0,%eax
L181:
  mov    %eax,%ecx
  xor    $0x1,%eax
  cmp    $0x22,%dl
  cmovne %ecx,%eax
  add    $0x1,%rbx
  movzbl (%rbx),%edx
  test   %dl,%dl
  je     L286
  cmp    $0x2c,%dl
  jne    L181
  test   %eax,%eax
  jne    L181
L286:
  mov    %ebx,%edx
  sub    %edi,%edx
  mov    $0x3d,%esi
  call   <memchr@plt>
  mov    %rax,%r13
  test   %rax,%rax
  cmove  %rbx,%r13
  mov    (%r14),%rsi
  test   %rsi,%rsi
  je     L339
  mov    $0x0,%ebp
  jmp    L91
L151:
  mov    %rdi,%rbx
  jmp    L286
L194:
  add    $0x1,%r13
  mov    %r13,(%r15)
L349:
  movzbl 0x0(%r13),%eax
  cmp    $0x20,%al
  je     L194
  cmp    $0x9,%al
  je     L194
  cmp    $0x22,%al
  ja     L239
  bt     %rax,%rdx
  jb     L194
L239:
  mov    %rbx,%rax
  cmpb   $0x0,(%rbx)
  je     L270
  movb   $0x0,(%rbx)
  lea    0x1(%rbx),%rax
L270:
  mov    %rax,(%r12)
  sub    $0x1,%rbx
  movabs $0x400002400,%rdx
  jmp    L330
L101:
  sub    $0x1,%rbx
  movb   $0x0,0x1(%rbx)
L330:
  movzbl (%rbx),%eax
  cmp    $0x20,%al
  je     L101
  cmp    $0x9,%al
  je     L101
  cmp    $0x22,%al
  ja     L184
  bt     %rax,%rdx
  jb     L101
L184:
  mov    (%r12),%rax
  movzbl (%rax),%edx
  cmp    $0x20,%dl
  ja     L268
  movabs $0x100002600,%rcx
  bt     %rdx,%rcx
  jae    L268
  add    $0x1,%rax
  jmp    L121
L203:
  add    $0x1,%rax
  bt     %rdx,%rcx
  jae    L268
L121:
  mov    %rax,(%r12)
  movzbl (%rax),%edx
  cmp    $0x20,%dl
  ja     L268
  jmp    L203
L207:
  add    $0x1,%rbp
  mov    (%r14,%rbp,8),%rsi
  test   %rsi,%rsi
  je     L339
L91:
  mov    %ebp,0xc(%rsp)
  mov    (%r12),%rdi
  mov    %r13d,%edx
  sub    %edi,%edx
  call   <memcmp@plt>
  test   %rax,%rax
  jne    L207
  mov    %r13,%rax
  sub    (%r12),%rax
  mov    (%r14,%rbp,8),%rdx
  cmpb   $0x0,(%rdx,%rax,1)
  jne    L207
  cmp    %rbx,%r13
  je     L223
  add    $0x1,%r13
  mov    %r13,(%r15)
  movabs $0x400002400,%rdx
  jmp    L349
L339:
  mov    (%r12),%rax
  mov    %rax,(%r15)
  cmpb   $0x0,(%rbx)
  je     L78
  movb   $0x0,(%rbx)
  lea    0x1(%rbx),%rbx
L78:
  mov    %rbx,(%r12)
  movzbl (%rbx),%eax
  movl   $0xffffffff,0xc(%rsp)
  cmp    $0x20,%al
  ja     L268
  movabs $0x100002600,%rdx
  bt     %rax,%rdx
  jae    L142
  add    $0x1,%rbx
  jmp    L340
L4:
  add    $0x1,%rbx
  bt     %rax,%rdx
  jae    L33
L340:
  mov    %rbx,(%r12)
  movzbl (%rbx),%eax
  cmp    $0x20,%al
  jbe    L4
  movl   $0xffffffff,0xc(%rsp)
L268:
  mov    0xc(%rsp),%eax
  add    $0x18,%rsp
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
L33:
  movl   $0xffffffff,0xc(%rsp)
  jmp    L268
L212:
  movl   $0xffffffff,0xc(%rsp)
  jmp    L268
L142:
  movl   $0xffffffff,0xc(%rsp)
  jmp    L268
L223:
  movq   $0x0,(%r15)
  jmp    L239
```

assistant: ```c
int digest_md5_getsubopt(char **optionp, const char *const *tokens, char **valuep) {
  char *endp, *vstart;
  int cnt;
  int inside_quote = 0;
  if (**optionp == '\0')
    return -1;
  endp = *optionp;
  while (*endp != '\0' && (inside_quote || (!inside_quote && *endp != ','))) {
    if (*endp == '"')
      inside_quote = !inside_quote;
    endp++;
  }
  vstart = memchr(*optionp, '=', endp - *optionp);
  if (vstart == NULL)
    vstart = endp;
  for (cnt = 0; tokens[cnt] != NULL; ++cnt)
    if (memcmp(*optionp, tokens[cnt], vstart - *optionp) == 0 && tokens[cnt][vstart - *optionp] == '\0') {
      *valuep = vstart != endp ? vstart + 1 : NULL;
      while (*valuep && (**valuep == ' ' || **valuep == '\t' || **valuep == '\r' || **valuep == '\n' || **valuep == '"'))
        (*valuep)++;
      if (*endp != '\0') {
        *endp = '\0';
        *optionp = endp + 1;
      } else
        *optionp = endp;
      endp--;
      while (*endp == ' ' || *endp == '\t' || *endp == '\r' || *endp == '\n' || *endp == '"')
        *endp-- = '\0';
      while (**optionp == ' ' || **optionp == '\t' || **optionp == '\r' || **optionp == '\n')
        (*optionp)++;
      return cnt;
    }
  *valuep = *optionp;
  if (*endp != '\0')
    *endp++ = '\0';
  *optionp = endp;
  while (**optionp == ' ' || **optionp == '\t' || **optionp == '\r' || **optionp == '\n')
    (*optionp)++;
  return -1;
}
```