user: 提供的汇编代码用C语言表示会是什么样子：

```asm
<pat_next>:
  endbr64
  push   %rbp
  push   %rbx
  sub    $0x18,%rsp
  mov    %rdx,%rbx
  mov    %fs:0x28,%rax
  mov    %rax,0x8(%rsp)
  xor    %eax,%eax
  test   %rsi,%rsi
  je     L320
  cmpb   $0x0,(%rdi)
  je     L320
  movq   $0x1,(%rdx)
  movzbl (%rdi),%eax
  cmp    $0x5c,%al
  je     L226
  cmp    $0x5b,%al
  je     L170
  cmp    $0x2a,%al
  je     L19
  cmp    $0x3f,%al
  je     L450
  mov    $0x0,%ebp
L460:
  movzbl (%rdi),%eax
  test   %al,%al
  jns    L53
  lea    0x4(%rsp),%rax
  mov    %rsi,%rdx
  mov    %rdi,%rsi
  mov    %rax,%rdi
  call   <mbtowc@plt>
  test   %eax,%eax
  js     L455
  add    %eax,%ebp
  movslq %ebp,%rbp
  mov    %rbp,(%rbx)
  mov    0x4(%rsp),%eax
  jmp    L413
L320:
  movq   $0x0,(%rbx)
  mov    $0x0,%eax
L413:
  mov    0x8(%rsp),%rdx
  sub    %fs:0x28,%rdx
  jne    L270
  add    $0x18,%rsp
  pop    %rbx
  pop    %rbp
  ret
L226:
  cmpb   $0x0,0x1(%rdi)
  je     L148
  mov    D9(%rip),%rax
  and    (%rax),%ecx
  je     L284
L148:
  movzbl (%rdi),%eax
L53:
  movsbl %al,%eax
  jmp    L413
L284:
  movq   $0x2,(%rdx)
  add    $0x1,%rdi
  mov    $0x1,%ebp
  jmp    L460
L170:
  cmp    $0x1,%rsi
  jbe    L155
  movzbl 0x1(%rdi),%eax
  cmp    $0x5e,%al
  sete   %dl
  cmp    $0x21,%al
  sete   %al
  or     %eax,%edx
  movzbl %dl,%edx
  lea    0x1(%rdx),%rax
  cmp    %rax,%rsi
  jbe    L58
  cmpb   $0x5d,0x1(%rdi,%rdx,1)
  jne    L238
  lea    0x2(%rdx),%rax
  cmp    %rax,%rsi
  jbe    L442
L238:
  movabs $0x2400400000000000,%r9
  jmp    L172
L442:
  mov    %rax,%rcx
  jmp    L14
L297:
  cmp    $0x3d,%r8b
  ja     L267
  bt     %r8,%r9
  jb     L91
L267:
  add    $0x1,%rax
  jmp    L172
L91:
  lea    0x2(%rax),%rdx
  cmp    %rdx,%rsi
  jbe    L519
  cmpb   $0x0,0x2(%rdi,%rax,1)
  je     L411
  lea    0x3(%rax),%rdx
  cmp    %rdx,%rsi
  ja     L411
L519:
  cmp    %rdx,%rsi
  je     L336
  cmpb   $0x0,(%rdi,%rdx,1)
  je     L440
L207:
  lea    0x1(%rdx),%rax
  cmp    %rax,%rsi
  jbe    L55
L172:
  movzbl (%rdi,%rax,1),%edx
  cmp    $0x5d,%dl
  je     L88
  test   %dl,%dl
  je     L88
  lea    0x1(%rax),%rcx
  cmp    %rsi,%rcx
  jae    L14
  movzbl 0x1(%rdi,%rax,1),%r8d
  cmp    $0x5b,%dl
  jne    L249
  test   %r8b,%r8b
  jne    L297
L249:
  mov    %rcx,%rax
  jmp    L172
L111:
  add    $0x1,%rdx
  cmp    %rdx,%rsi
  jbe    L519
L411:
  movzbl (%rdi,%rdx,1),%eax
  test   %al,%al
  je     L519
  cmp    %r8b,-0x1(%rdi,%rdx,1)
  jne    L111
  cmp    $0x5d,%al
  jne    L111
  cmp    %rdx,%rsi
  jne    L207
  mov    $0x5b,%eax
  jmp    L413
L88:
  mov    %rax,%rcx
L14:
  cmp    %rsi,%rcx
  je     L392
  mov    $0x5b,%eax
  cmpb   $0x0,(%rdi,%rcx,1)
  je     L413
  add    $0x1,%rcx
  mov    %rcx,(%rbx)
  mov    $0xfffffffd,%eax
  jmp    L413
L55:
  mov    %rax,%rcx
  jmp    L14
L455:
  movq   $0x0,(%rbx)
  mov    $0xfffffffe,%eax
  jmp    L413
L336:
  mov    $0x5b,%eax
  jmp    L413
L440:
  mov    $0x5b,%eax
  jmp    L413
L392:
  mov    $0x5b,%eax
  jmp    L413
L19:
  mov    $0xfffffffb,%eax
  jmp    L413
L450:
  mov    $0xfffffffc,%eax
  jmp    L413
L155:
  mov    $0x1,%eax
L58:
  mov    %rax,%rcx
  jmp    L14
L270:
  call   <__stack_chk_fail@plt>
```

assistant: ```c
int pat_next(const char *pat, size_t m, size_t *step, int flags) {
  int esc = 0;
  if (!m || !*pat) {
    *step = 0;
    return 0;
  }
  *step = 1;
  if (pat[0] == '\\' && pat[1] && !(flags & FNM_NOESCAPE)) {
    *step = 2;
    pat++;
    esc = 1;
    goto escaped;
  }
  if (pat[0] == '[') {
    size_t k = 1;
    if (k < m)
      if (pat[k] == '^' || pat[k] == '!')
        k++;
    if (k < m)
      if (pat[k] == ']')
        k++;
    for (; k < m && pat[k] && pat[k] != ']'; k++) {
      if (k + 1 < m && pat[k + 1] && pat[k] == '[' && (pat[k + 1] == ':' || pat[k + 1] == '.' || pat[k + 1] == '=')) {
        int z = pat[k + 1];
        k += 2;
        if (k < m && pat[k])
          k++;
        while (k < m && pat[k] && (pat[k - 1] != z || pat[k] != ']'))
          k++;
        if (k == m || !pat[k])
          break;
      }
    }
    if (k == m || !pat[k]) {
      *step = 1;
      return '[';
    }
    *step = k + 1;
    return -3;
  }
  if (pat[0] == '*')
    return -5;
  if (pat[0] == '?')
    return -4;
escaped:
  if (pat[0] >= 128U) {
    wchar_t wc;
    int k = mbtowc(&wc, pat, m);
    if (k < 0) {
      *step = 0;
      return -2;
    }
    *step = k + esc;
    return wc;
  }
  return pat[0];
}
```