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

```asm
<is_a_number>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  sub    $0x20,%rsp
  mov    %rdi,-0x18(%rbp)
  movl   $0x0,-0xc(%rbp)
  mov    -0xc(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x18(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  cmp    $0x2b,%al
  je     L230
  mov    -0xc(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x18(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  cmp    $0x2d,%al
  jne    L257
L230:
  addl   $0x1,-0xc(%rbp)
L257:
  mov    -0xc(%rbp),%eax
  mov    %eax,-0x8(%rbp)
  jmp    L26
L61:
  addl   $0x1,-0xc(%rbp)
L26:
  mov    -0xc(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x18(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  cmp    $0x2f,%al
  jle    L112
  mov    -0xc(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x18(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  cmp    $0x39,%al
  jle    L61
L112:
  mov    -0xc(%rbp),%eax
  sub    -0x8(%rbp),%eax
  mov    %eax,-0x4(%rbp)
  cmpl   $0x0,-0x4(%rbp)
  jne    L203
  mov    -0xc(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x18(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  cmp    $0x2e,%al
  je     L203
  mov    $0x0,%eax
  jmp    L178
L203:
  mov    -0xc(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x18(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  test   %al,%al
  jne    L248
  mov    $0x1,%eax
  jmp    L178
L248:
  mov    -0xc(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x18(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  movsbl %al,%eax
  mov    %eax,%edi
  call   <tolower@plt>
  cmp    $0x65,%al
  je     L171
  mov    -0xc(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x18(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  movsbl %al,%eax
  mov    %eax,%edi
  call   <tolower@plt>
  cmp    $0x64,%al
  jne    L102
L171:
  mov    -0xc(%rbp),%eax
  cltq
  lea    0x1(%rax),%rdx
  mov    -0x18(%rbp),%rax
  add    %rdx,%rax
  mov    %rax,%rdi
  call   <rest_pmdigits@plt>
  jmp    L178
L102:
  mov    -0xc(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x18(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  cmp    $0x2e,%al
  je     L177
  mov    $0x0,%eax
  jmp    L178
L177:
  addl   $0x1,-0xc(%rbp)
  mov    -0xc(%rbp),%eax
  mov    %eax,-0x8(%rbp)
  jmp    L243
L192:
  addl   $0x1,-0xc(%rbp)
L243:
  mov    -0xc(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x18(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  cmp    $0x2f,%al
  jle    L176
  mov    -0xc(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x18(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  cmp    $0x39,%al
  jle    L192
L176:
  cmpl   $0x0,-0x4(%rbp)
  jne    L58
  mov    -0xc(%rbp),%eax
  cmp    -0x8(%rbp),%eax
  jne    L58
  mov    $0x0,%eax
  jmp    L178
L58:
  mov    -0xc(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x18(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  test   %al,%al
  jne    L9
  mov    $0x1,%eax
  jmp    L178
L9:
  mov    -0xc(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x18(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  movsbl %al,%eax
  mov    %eax,%edi
  call   <tolower@plt>
  cmp    $0x65,%al
  je     L44
  mov    -0xc(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x18(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  movsbl %al,%eax
  mov    %eax,%edi
  call   <tolower@plt>
  cmp    $0x64,%al
  jne    L72
L44:
  mov    -0xc(%rbp),%eax
  cltq
  lea    0x1(%rax),%rdx
  mov    -0x18(%rbp),%rax
  add    %rdx,%rax
  mov    %rax,%rdi
  call   <rest_pmdigits@plt>
  jmp    L178
L72:
  mov    $0x0,%eax
L178:
  leave
  ret
```

assistant: ```c
int is_a_number(char *s) {
  int i, j, dc1;
  i = 0;
  if (s[i] == '+' || s[i] == '-')
    i++;
  for (j = i; s[i] >= '0' && s[i] <= '9'; i++)
    ;
  dc1 = i - j;
  if (dc1 == 0 && s[i] != '.')
    return (0);
  if (s[i] == '\0')
    return (1);
  if (tolower(s[i]) == 'e' || tolower(s[i]) == 'd')
    return (rest_pmdigits(&s[i + 1]));
  if (s[i] != '.')
    return (0);
  for (i++, j = i; s[i] >= '0' && s[i] <= '9'; i++)
    ;
  if (dc1 == 0 && i == j)
    return (0);
  if (s[i] == '\0')
    return (1);
  if (tolower(s[i]) == 'e' || tolower(s[i]) == 'd')
    return (rest_pmdigits(&s[i + 1]));
  return (0);
}
```