#include <limits.h>
#include <mruby.h>

static inline mrb_int
to_int(mrb_value x)
{
  double f;

  if (mrb_fixnum_p(x)) return mrb_fixnum(x);
  f = mrb_float(x);
  return (mrb_int)f;
}

/*
 *  Document-method: Integer#chr
 *  call-seq:
 *     int.chr  ->  string
 *
 *  Returns a string containing the character represented by the +int+'s value
 *  according to +encoding+.
 *
 *     65.chr    #=> "A"
 *     230.chr   #=> "\xE6"
 */
static mrb_value
mrb_int_chr(mrb_state *mrb, mrb_value x)
{
  mrb_int chr;
  char c;

  chr = to_int(x);
  if (chr >= (1 << CHAR_BIT)) {
    mrb_raisef(mrb, E_RANGE_ERROR, "%S out of char range", x);
  }
  c = (char)chr;

  return mrb_str_new(mrb, &c, 1);
}

/*
 *  call-seq:
 *     int.allbits?(mask)  ->  true or false
 *
 *  Returns +true+ if all bits of <code>+int+ & +mask+</code> are 1.
 */
static mrb_value
mrb_int_allbits(mrb_state *mrb, mrb_value self)
{
  mrb_int n, m;

  n = to_int(self);
  mrb_get_args(mrb, "i", &m);
  return mrb_bool_value((n & m) == m);
}

/*
 *  call-seq:
 *     int.anybits?(mask)  ->  true or false
 *
 *  Returns +true+ if any bits of <code>+int+ & +mask+</code> are 1.
 */
static mrb_value
mrb_int_anybits(mrb_state *mrb, mrb_value self)
{
  mrb_int n, m;

  n = to_int(self);
  mrb_get_args(mrb, "i", &m);
  return mrb_bool_value((n & m) != 0);
}

/*
 *  call-seq:
 *     int.nobits?(mask)  ->  true or false
 *
 *  Returns +true+ if no bits of <code>+int+ & +mask+</code> are 1.
 */
static mrb_value
mrb_int_nobits(mrb_state *mrb, mrb_value self)
{
  mrb_int n, m;

  n = to_int(self);
  mrb_get_args(mrb, "i", &m);
  return mrb_bool_value((n & m) == 0);
}

void
mrb_mruby_numeric_ext_gem_init(mrb_state* mrb)
{
  struct RClass *i = mrb_module_get(mrb, "Integral");

  mrb_define_method(mrb, i, "chr", mrb_int_chr, MRB_ARGS_NONE());
  mrb_define_method(mrb, i, "allbits?", mrb_int_allbits, MRB_ARGS_REQ(1));
  mrb_define_method(mrb, i, "anybits?", mrb_int_anybits, MRB_ARGS_REQ(1));
  mrb_define_method(mrb, i, "nobits?", mrb_int_nobits, MRB_ARGS_REQ(1));
}

void
mrb_mruby_numeric_ext_gem_final(mrb_state* mrb)
{
}