user: What is the c source code of the assembly code below:

```asm
<loc_aton>:
  endbr64
  push   %r15
  push   %r14
  push   %r13
  push   %r12
  push   %rbp
  push   %rbx
  sub    $0x38,%rsp
  mov    %rdi,%rbx
  mov    %rsi,%rbp
  mov    %fs:0x28,%rax
  mov    %rax,0x28(%rsp)
  xor    %eax,%eax
  movl   $0x0,0x18(%rsp)
  movl   $0x0,0x1c(%rsp)
  mov    %rdi,0x20(%rsp)
  call   <strlen@plt>
  mov    %eax,%r15d
  lea    0x18(%rsp),%rsi
  lea    0x20(%rsp),%r13
  mov    %r13,%rdi
  call   <latlon2ul@plt>
  mov    %eax,%r12d
  lea    0x1c(%rsp),%rsi
  mov    %r13,%rdi
  call   <latlon2ul@plt>
  mov    %eax,%r13d
  mov    0x18(%rsp),%edx
  mov    0x1c(%rsp),%eax
  lea    (%rdx,%rax,1),%esi
  mov    $0x0,%ecx
  cmp    $0x3,%esi
  je     L92
L399:
  mov    0x28(%rsp),%rax
  sub    %fs:0x28,%rax
  jne    L204
  mov    %ecx,%eax
  add    $0x38,%rsp
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
L92:
  cmp    $0x2,%eax
  jne    L105
  cmp    $0x1,%edx
  je     L391
L105:
  cmp    $0x1,%eax
  jne    L230
  cmp    $0x2,%edx
  je     L187
L230:
  mov    $0x0,%ecx
  jmp    L399
L391:
  mov    %r13d,%eax
  mov    %r12d,%r13d
  mov    %eax,%r12d
L187:
  mov    0x20(%rsp),%rax
  movl   $0x1,(%rsp)
  cmpb   $0x2d,(%rax)
  je     L268
L57:
  mov    0x20(%rsp),%rax
  cmpb   $0x2b,(%rax)
  je     L224
L343:
  mov    $0x0,%r14d
  jmp    L158
L268:
  add    $0x1,%rax
  mov    %rax,0x20(%rsp)
  movl   $0xffffffff,(%rsp)
  jmp    L57
L224:
  add    $0x1,%rax
  mov    %rax,0x20(%rsp)
  jmp    L343
L318:
  lea    (%r14,%r14,4),%edx
  mov    0x20(%rsp),%rax
  lea    0x1(%rax),%rcx
  mov    %rcx,0x20(%rsp)
  movsbl (%rax),%eax
  lea    -0x30(%rax,%rdx,2),%r14d
L158:
  mov    0x20(%rsp),%rax
  movzbl (%rax),%edi
  call   <isdigit@plt>
  test   %rax,%rax
  jne    L318
  mov    0x20(%rsp),%rax
  movl   $0x0,0x8(%rsp)
  cmpb   $0x2e,(%rax)
  je     L431
L330:
  movslq %r15d,%r15
  add    %r15,%rbx
  imul   $0x64,%r14d,%r14d
  add    0x8(%rsp),%r14d
  imul   (%rsp),%r14d
  add    $0x989680,%r14d
L74:
  mov    0x20(%rsp),%rax
  movzbl (%rax),%edi
  call   <isspace@plt>
  test   %rax,%rax
  jne    L342
  mov    0x20(%rsp),%rax
  cmp    %rbx,%rax
  jae    L342
  add    $0x1,%rax
  mov    %rax,0x20(%rsp)
  jmp    L74
L431:
  lea    0x1(%rax),%rdx
  mov    %rdx,0x20(%rsp)
  movzbl 0x1(%rax),%edi
  call   <isdigit@plt>
  movl   $0x0,0x8(%rsp)
  test   %rax,%rax
  je     L330
  mov    0x20(%rsp),%rax
  lea    0x1(%rax),%rdx
  mov    %rdx,0x20(%rsp)
  movsbl (%rax),%edx
  lea    -0xf0(%rdx,%rdx,4),%edx
  add    %edx,%edx
  mov    %edx,0xc(%rsp)
  mov    %edx,0x8(%rsp)
  movzbl 0x1(%rax),%edi
  call   <isdigit@plt>
  test   %rax,%rax
  je     L330
  mov    0x20(%rsp),%rax
  lea    0x1(%rax),%rdx
  mov    %rdx,0x20(%rsp)
  movsbl (%rax),%eax
  mov    0xc(%rsp),%edx
  lea    -0x30(%rdx,%rax,1),%eax
  mov    %eax,0x8(%rsp)
  jmp    L330
L215:
  add    $0x1,%rax
  mov    %rax,0x20(%rsp)
L342:
  mov    0x20(%rsp),%rax
  movzbl (%rax),%edi
  call   <isspace@plt>
  test   %rax,%rax
  je     L149
  mov    0x20(%rsp),%rax
  cmp    %rbx,%rax
  jb     L215
  mov    $0x12,%r15d
  mov    $0x13,%eax
  movq   $0x16,(%rsp)
L84:
  movl   $0x0,0x0(%rbp)
  mov    %r15d,0x4(%rbp)
  mov    (%rsp),%ecx
  mov    %ecx,0x8(%rbp)
  lea    0x10(%rbp),%rbx
  mov    %eax,0xc(%rbp)
  mov    %rbx,%rsi
  mov    %r13d,%edi
  call   <PUTLONG@plt>
  mov    %rbx,%rsi
  mov    %r12d,%edi
  call   <PUTLONG@plt>
  mov    %rbx,%rsi
  mov    %r14d,%edi
  call   <PUTLONG@plt>
  mov    $0x10,%ecx
  jmp    L399
L149:
  cmp    %rbx,0x20(%rsp)
  jae    L138
  lea    0x20(%rsp),%rdi
  call   <precsize_aton@plt>
  mov    %rax,%r15
  jmp    L16
L41:
  add    $0x1,%rax
  mov    %rax,0x20(%rsp)
L16:
  mov    0x20(%rsp),%rax
  movzbl (%rax),%edi
  call   <isspace@plt>
  test   %rax,%rax
  jne    L154
  mov    0x20(%rsp),%rax
  cmp    %rbx,%rax
  jb     L41
L154:
  mov    0x20(%rsp),%rax
  movzbl (%rax),%edi
  call   <isspace@plt>
  test   %rax,%rax
  je     L26
  mov    0x20(%rsp),%rax
  cmp    %rbx,%rax
  jae    L315
  add    $0x1,%rax
  mov    %rax,0x20(%rsp)
  jmp    L154
L315:
  mov    $0x13,%eax
  movq   $0x16,(%rsp)
  jmp    L84
L26:
  cmp    %rbx,0x20(%rsp)
  jae    L254
  lea    0x20(%rsp),%rdi
  call   <precsize_aton@plt>
  mov    %rax,(%rsp)
  jmp    L419
L405:
  add    $0x1,%rax
  mov    %rax,0x20(%rsp)
L419:
  mov    0x20(%rsp),%rax
  movzbl (%rax),%edi
  call   <isspace@plt>
  test   %rax,%rax
  jne    L278
  mov    0x20(%rsp),%rax
  cmp    %rbx,%rax
  jb     L405
  jmp    L278
L340:
  add    $0x1,%rax
  mov    %rax,0x20(%rsp)
L278:
  mov    0x20(%rsp),%rax
  movzbl (%rax),%edi
  call   <isspace@plt>
  test   %rax,%rax
  je     L296
  mov    0x20(%rsp),%rax
  cmp    %rbx,%rax
  jb     L340
  mov    $0x13,%eax
  jmp    L84
L296:
  cmp    %rbx,0x20(%rsp)
  jae    L66
  lea    0x20(%rsp),%rdi
  call   <precsize_aton@plt>
  jmp    L84
L138:
  mov    $0x12,%r15d
  mov    $0x13,%eax
  movq   $0x16,(%rsp)
  jmp    L84
L254:
  mov    $0x13,%eax
  movq   $0x16,(%rsp)
  jmp    L84
L66:
  mov    $0x13,%eax
  jmp    L84
L204:
  call   <__stack_chk_fail@plt>
```

assistant: ```c
int loc_aton(const char *ascii, u_char *binary) {
  const char *cp, *maxcp;
  u_char *bcp;
  u_int32_t latit = 0, longit = 0, alt = 0;
  u_int32_t lltemp1 = 0, lltemp2 = 0;
  int altmeters = 0, altfrac = 0, altsign = 1;
  u_int8_t hp = 0x16;
  u_int8_t vp = 0x13;
  u_int8_t siz = 0x12;
  int which1 = 0, which2 = 0;
  cp = ascii;
  maxcp = cp + strlen(ascii);
  lltemp1 = latlon2ul((char **)&cp, &which1);
  lltemp2 = latlon2ul((char **)&cp, &which2);
  switch (which1 + which2) {
  case 3:
    if ((which1 == 1) && (which2 == 2)) {
      latit = lltemp1;
      longit = lltemp2;
    } else if ((which1 == 2) && (which2 == 1)) {
      longit = lltemp1;
      latit = lltemp2;
    } else {
      return (0);
    }
    break;
  default:
    return (0);
  }
  if (*cp == '-') {
    altsign = -1;
    cp++;
  }
  if (*cp == '+')
    cp++;
  while (isdigit((unsigned char)*cp))
    altmeters = altmeters * 10 + (*cp++ - '0');
  if (*cp == '.') {
    cp++;
    if (isdigit((unsigned char)*cp)) {
      altfrac = (*cp++ - '0') * 10;
      if (isdigit((unsigned char)*cp)) {
        altfrac += (*cp++ - '0');
      }
    }
  }
  alt = (10000000 + (altsign * (altmeters * 100 + altfrac)));
  while (!isspace((unsigned char)*cp) && (cp < maxcp))
    cp++;
  while (isspace((unsigned char)*cp) && (cp < maxcp))
    cp++;
  if (cp >= maxcp)
    goto defaults;
  siz = precsize_aton(&cp);
  while (!isspace((unsigned char)*cp) && (cp < maxcp))
    cp++;
  while (isspace((unsigned char)*cp) && (cp < maxcp))
    cp++;
  if (cp >= maxcp)
    goto defaults;
  hp = precsize_aton(&cp);
  while (!isspace((unsigned char)*cp) && (cp < maxcp))
    cp++;
  while (isspace((unsigned char)*cp) && (cp < maxcp))
    cp++;
  if (cp >= maxcp)
    goto defaults;
  vp = precsize_aton(&cp);
defaults:
  bcp = binary;
  *bcp++ = (u_int8_t)0;
  *bcp++ = siz;
  *bcp++ = hp;
  *bcp++ = vp;
  PUTLONG(latit, bcp);
  PUTLONG(longit, bcp);
  PUTLONG(alt, bcp);
  return (16);
}
```