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

```asm
<dt_parse_iso_zone_lenient>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  sub    $0x40,%rsp
  mov    %rdi,-0x28(%rbp)
  mov    %rsi,-0x30(%rbp)
  mov    %rdx,-0x38(%rbp)
  cmpq   $0x0,-0x30(%rbp)
  jne    L562
  mov    $0x0,%eax
  jmp    L507
L562:
  mov    -0x28(%rbp),%rax
  mov    %rax,-0x8(%rbp)
  mov    -0x8(%rbp),%rax
  movzbl (%rax),%eax
  movzbl %al,%eax
  cmp    $0x7a,%eax
  je     L279
  cmp    $0x7a,%eax
  jg     L245
  cmp    $0x5a,%eax
  je     L279
  cmp    $0x5a,%eax
  jg     L245
  cmp    $0x55,%eax
  je     L294
  cmp    $0x55,%eax
  jg     L245
  cmp    $0x47,%eax
  je     L445
  cmp    $0x47,%eax
  jg     L245
  cmp    $0x2b,%eax
  je     L177
  cmp    $0x2d,%eax
  je     L172
  jmp    L245
L279:
  movl   $0x0,-0x20(%rbp)
  movq   $0x1,-0x10(%rbp)
  jmp    L139
L445:
  cmpq   $0x2,-0x30(%rbp)
  jbe    L401
  mov    -0x8(%rbp),%rax
  add    $0x1,%rax
  movzbl (%rax),%eax
  cmp    $0x4d,%al
  jne    L401
  mov    -0x8(%rbp),%rax
  add    $0x2,%rax
  movzbl (%rax),%eax
  cmp    $0x54,%al
  je     L127
L401:
  mov    $0x0,%eax
  jmp    L507
L127:
  cmpq   $0x3,-0x30(%rbp)
  jbe    L92
  mov    -0x8(%rbp),%rax
  add    $0x3,%rax
  movzbl (%rax),%eax
  cmp    $0x2b,%al
  je     L150
  mov    -0x8(%rbp),%rax
  add    $0x3,%rax
  movzbl (%rax),%eax
  cmp    $0x2d,%al
  jne    L92
L150:
  mov    -0x30(%rbp),%rax
  lea    -0x3(%rax),%rsi
  mov    -0x28(%rbp),%rax
  lea    0x3(%rax),%rcx
  mov    -0x38(%rbp),%rax
  mov    %rax,%rdx
  mov    %rcx,%rdi
  call   <dt_parse_iso_zone_lenient>
  mov    %rax,-0x10(%rbp)
  cmpq   $0x0,-0x10(%rbp)
  jne    L64
  mov    $0x0,%eax
  jmp    L507
L64:
  mov    -0x10(%rbp),%rax
  add    $0x3,%rax
  jmp    L507
L92:
  movl   $0x0,-0x20(%rbp)
  movq   $0x3,-0x10(%rbp)
  jmp    L139
L294:
  cmpq   $0x2,-0x30(%rbp)
  jbe    L351
  mov    -0x8(%rbp),%rax
  add    $0x1,%rax
  movzbl (%rax),%eax
  cmp    $0x54,%al
  jne    L351
  mov    -0x8(%rbp),%rax
  add    $0x2,%rax
  movzbl (%rax),%eax
  cmp    $0x43,%al
  je     L39
L351:
  mov    $0x0,%eax
  jmp    L507
L39:
  cmpq   $0x3,-0x30(%rbp)
  jbe    L454
  mov    -0x8(%rbp),%rax
  add    $0x3,%rax
  movzbl (%rax),%eax
  cmp    $0x2b,%al
  je     L109
  mov    -0x8(%rbp),%rax
  add    $0x3,%rax
  movzbl (%rax),%eax
  cmp    $0x2d,%al
  jne    L454
L109:
  mov    -0x30(%rbp),%rax
  lea    -0x3(%rax),%rsi
  mov    -0x28(%rbp),%rax
  lea    0x3(%rax),%rcx
  mov    -0x38(%rbp),%rax
  mov    %rax,%rdx
  mov    %rcx,%rdi
  call   <dt_parse_iso_zone_lenient>
  mov    %rax,-0x10(%rbp)
  cmpq   $0x0,-0x10(%rbp)
  jne    L424
  mov    $0x0,%eax
  jmp    L507
L424:
  mov    -0x10(%rbp),%rax
  add    $0x3,%rax
  jmp    L507
L454:
  movl   $0x0,-0x20(%rbp)
  movq   $0x3,-0x10(%rbp)
  jmp    L139
L177:
  movl   $0x1,-0x14(%rbp)
  jmp    L589
L172:
  movl   $0xffffffff,-0x14(%rbp)
  jmp    L589
L245:
  mov    $0x0,%eax
  jmp    L507
L589:
  cmpq   $0x1,-0x30(%rbp)
  ja     L106
  mov    $0x0,%eax
  jmp    L507
L106:
  mov    -0x30(%rbp),%rdx
  mov    -0x8(%rbp),%rax
  mov    $0x1,%esi
  mov    %rax,%rdi
  call   <count_digits@plt>
  cltq
  mov    %rax,-0x10(%rbp)
  movl   $0x0,-0x18(%rbp)
  cmpq   $0x4,-0x10(%rbp)
  je     L345
  cmpq   $0x4,-0x10(%rbp)
  ja     L529
  cmpq   $0x1,-0x10(%rbp)
  je     L416
  cmpq   $0x2,-0x10(%rbp)
  je     L236
  jmp    L529
L416:
  mov    -0x8(%rbp),%rax
  mov    $0x1,%edx
  mov    $0x1,%esi
  mov    %rax,%rdi
  call   <parse_number@plt>
  mov    %eax,-0x1c(%rbp)
  movq   $0x2,-0x10(%rbp)
  jmp    L223
L236:
  mov    -0x8(%rbp),%rax
  mov    $0x2,%edx
  mov    $0x1,%esi
  mov    %rax,%rdi
  call   <parse_number@plt>
  mov    %eax,-0x1c(%rbp)
  movq   $0x3,-0x10(%rbp)
  jmp    L223
L345:
  mov    -0x8(%rbp),%rax
  mov    $0x2,%edx
  mov    $0x1,%esi
  mov    %rax,%rdi
  call   <parse_number@plt>
  mov    %eax,-0x1c(%rbp)
  mov    -0x8(%rbp),%rax
  mov    $0x2,%edx
  mov    $0x3,%esi
  mov    %rax,%rdi
  call   <parse_number@plt>
  mov    %eax,-0x18(%rbp)
  movq   $0x5,-0x10(%rbp)
  jmp    L276
L529:
  mov    $0x0,%eax
  jmp    L507
L223:
  mov    -0x10(%rbp),%rax
  add    $0x1,%rax
  cmp    %rax,-0x30(%rbp)
  jb     L474
  mov    -0x8(%rbp),%rdx
  mov    -0x10(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  cmp    $0x3a,%al
  jne    L474
  addq   $0x1,-0x10(%rbp)
  mov    -0x30(%rbp),%rdx
  mov    -0x10(%rbp),%rcx
  mov    -0x8(%rbp),%rax
  mov    %rcx,%rsi
  mov    %rax,%rdi
  call   <count_digits@plt>
  cmp    $0x2,%eax
  je     L409
  mov    $0x0,%eax
  jmp    L507
L409:
  mov    -0x10(%rbp),%rcx
  mov    -0x8(%rbp),%rax
  mov    $0x2,%edx
  mov    %rcx,%rsi
  mov    %rax,%rdi
  call   <parse_number@plt>
  mov    %eax,-0x18(%rbp)
  addq   $0x2,-0x10(%rbp)
  jmp    L276
L474:
  nop
L276:
  cmpl   $0x17,-0x1c(%rbp)
  jg     L430
  cmpl   $0x3b,-0x18(%rbp)
  jle    L257
L430:
  mov    $0x0,%eax
  jmp    L507
L257:
  mov    -0x1c(%rbp),%eax
  imul   $0x3c,%eax,%edx
  mov    -0x18(%rbp),%eax
  add    %eax,%edx
  mov    -0x14(%rbp),%eax
  imul   %edx,%eax
  mov    %eax,-0x20(%rbp)
L139:
  cmpq   $0x0,-0x38(%rbp)
  je     L458
  mov    -0x38(%rbp),%rax
  mov    -0x20(%rbp),%edx
  mov    %edx,(%rax)
L458:
  mov    -0x10(%rbp),%rax
L507:
  leave
  ret
```

assistant: ```c
size_t dt_parse_iso_zone_lenient(const char *str, size_t len, int *op) {
  const unsigned char *p;
  int o, h, m, sign;
  size_t n;
  if (len < 1)
    return 0;
  p = (const unsigned char *)str;
  switch (*p) {
  case 'z':
  case 'Z':
    o = 0;
    n = 1;
    goto zulu;
  case 'G':
    if (len < 3 || p[1] != 'M' || p[2] != 'T')
      return 0;
    if (len > 3 && (p[3] == '+' || p[3] == '-')) {
      if (!(n = dt_parse_iso_zone_lenient(str + 3, len - 3, op)))
        return 0;
      return n + 3;
    }
    o = 0;
    n = 3;
    goto zulu;
  case 'U':
    if (len < 3 || p[1] != 'T' || p[2] != 'C')
      return 0;
    if (len > 3 && (p[3] == '+' || p[3] == '-')) {
      if (!(n = dt_parse_iso_zone_lenient(str + 3, len - 3, op)))
        return 0;
      return n + 3;
    }
    o = 0;
    n = 3;
    goto zulu;
  case '+':
    sign = 1;
    break;
  case '-':
    sign = -1;
    break;
  default:
    return 0;
  }
  if (len < 2)
    return 0;
  n = count_digits(p, 1, len);
  m = 0;
  switch (n) {
  case 1:
    h = parse_number(p, 1, 1);
    n = 2;
    break;
  case 2:
    h = parse_number(p, 1, 2);
    n = 3;
    break;
  case 4:
    h = parse_number(p, 1, 2);
    m = parse_number(p, 3, 2);
    n = 5;
    goto hm;
  default:
    return 0;
  }
  if (len < n + 1 || p[n] != ':')
    goto hm;
  if (count_digits(p, ++n, len) != 2)
    return 0;
  m = parse_number(p, n, 2);
  n += 2;
hm:
  if (h > 23 || m > 59)
    return 0;
  o = sign * (h * 60 + m);
zulu:
  if (op)
    *op = o;
  return n;
}
```