text: /**
  ** @file mruby/boxing_word.h - word boxing mrb_value definition
  **
  ** See Copyright Notice in mruby.h
  */
  
  #ifndef MRUBY_BOXING_WORD_H
  #define MRUBY_BOXING_WORD_H
  
  #if defined(MRB_32BIT) && !defined(MRB_USE_FLOAT32)
  # define MRB_WORDBOX_USE_HEAP_FLOAT
  #endif
  
  #if !defined(MRB_NO_FLOAT) && defined(MRB_WORDBOX_USE_HEAP_FLOAT)
  struct RFloat {
    MRB_OBJECT_HEADER;
    mrb_float f;
  };
  #endif
  
  struct RInteger {
    MRB_OBJECT_HEADER;
    mrb_int i;
  };
  
  enum mrb_special_consts {
    MRB_Qnil    =  0,
    MRB_Qfalse  =  4,
    MRB_Qtrue   = 12,
    MRB_Qundef  = 20,
  };
  
  #if defined(MRB_64BIT) && defined(MRB_INT32)
  #define MRB_FIXNUM_SHIFT        0
  #else
  #define MRB_FIXNUM_SHIFT        WORDBOX_FIXNUM_SHIFT
  #endif
  #define MRB_SYMBOL_SHIFT        WORDBOX_SYMBOL_SHIFT
  
  #if defined(MRB_64BIT) && defined(MRB_INT64)
  # define MRB_FIXNUM_MIN (INT64_MIN>>MRB_FIXNUM_SHIFT)
  # define MRB_FIXNUM_MAX (INT64_MAX>>MRB_FIXNUM_SHIFT)
  #else
  # define MRB_FIXNUM_MIN (INT32_MIN>>MRB_FIXNUM_SHIFT)
  # define MRB_FIXNUM_MAX (INT32_MAX>>MRB_FIXNUM_SHIFT)
  #endif
  
  #define WORDBOX_FIXNUM_BIT_POS  1
  #define WORDBOX_FIXNUM_SHIFT    WORDBOX_FIXNUM_BIT_POS
  #define WORDBOX_FIXNUM_FLAG     (1 << (WORDBOX_FIXNUM_BIT_POS - 1))
  #define WORDBOX_FIXNUM_MASK     ((1 << WORDBOX_FIXNUM_BIT_POS) - 1)
  
  #if defined(MRB_WORDBOX_USE_HEAP_FLOAT)
  /* floats are allocated in heaps */
  #define WORDBOX_SYMBOL_BIT_POS  2
  #define WORDBOX_SYMBOL_SHIFT    WORDBOX_SYMBOL_BIT_POS
  #define WORDBOX_SYMBOL_FLAG     (1 << (WORDBOX_SYMBOL_BIT_POS - 1))
  #define WORDBOX_SYMBOL_MASK     ((1 << WORDBOX_SYMBOL_BIT_POS) - 1)
  #else
  #define WORDBOX_FLOAT_FLAG      2
  #define WORDBOX_FLOAT_MASK      3
  #if defined(MRB_64BIT)
  #define WORDBOX_SYMBOL_SHIFT    32
  #else  /* MRB_32BIT */
  #define WORDBOX_SYMBOL_SHIFT    5
  #endif
  #define WORDBOX_SYMBOL_FLAG     0x1c
  #define WORDBOX_SYMBOL_MASK     0x1f
  #endif
  
  #define WORDBOX_IMMEDIATE_MASK  0x07
  
  #define WORDBOX_SET_SHIFT_VALUE(o,n,v) \
    ((o).w = (((uintptr_t)(v)) << WORDBOX_##n##_SHIFT) | WORDBOX_##n##_FLAG)
  #define WORDBOX_SHIFT_VALUE_P(o,n) \
    (((o).w & WORDBOX_##n##_MASK) == WORDBOX_##n##_FLAG)
  #define WORDBOX_OBJ_TYPE_P(o,n) \
    (!mrb_immediate_p(o) && mrb_val_union(o).bp->tt == MRB_TT_##n)
  
  /*
   * mrb_value representation:
   *
   * 64bit word with inline float:
   *   nil   : ...0000 0000 (all bits are 0)
   *   false : ...0000 0100 (mrb_fixnum(v) != 0)
   *   true  : ...0000 1100
   *   undef : ...0001 0100
   *   symbol: ...0001 1100 (use only upper 32-bit as symbol value with MRB_64BIT)
   *   fixnum: ...IIII III1
   *   float : ...FFFF FF10 (51 bit significands; require MRB_64BIT)
   *   object: ...PPPP P000
   *
   * 32bit word with inline float:
   *   nil   : ...0000 0000 (all bits are 0)
   *   false : ...0000 0100 (mrb_fixnum(v) != 0)
   *   true  : ...0000 1100
   *   undef : ...0001 0100
   *   symbol: ...SSS1 1100 (use only upper 32-bit as symbol value with MRB_64BIT)
   *   symbol: ...SSS1 0100 (symbol occupies 20bits)
   *   fixnum: ...IIII III1
   *   float : ...FFFF FF10 (22 bit significands; require MRB_64BIT)
   *   object: ...PPPP P000
   *
   * and word boxing without inline float:
   *   nil   : ...0000 0000 (all bits are 0)
   *   false : ...0000 0100 (mrb_fixnum(v) != 0)
   *   true  : ...0000 1100
   *   undef : ...0001 0100
   *   fixnum: ...IIII III1
   *   symbol: ...SSSS SS10
   *   object: ...PPPP P000 (any bits are 1)
   */
  typedef struct mrb_value {
    uintptr_t w;
  } mrb_value;
  
  union mrb_value_ {
    void *p;
    struct RBasic *bp;
  #ifndef MRB_NO_FLOAT
  #ifndef MRB_WORDBOX_USE_HEAP_FLOAT
    mrb_float f;
  #else
    struct RFloat *fp;
  #endif
  #endif
    struct RInteger *ip;
    struct RCptr *vp;
    uintptr_t w;
    mrb_value value;
  };
  
  mrb_static_assert1(sizeof(mrb_value) == sizeof(union mrb_value_));
  
  static inline union mrb_value_
  mrb_val_union(mrb_value v)
  {
    union mrb_value_ x;
    x.value = v;
    return x;
  }
  
  MRB_API mrb_value mrb_word_boxing_cptr_value(struct mrb_state*, void*);
  #ifndef MRB_NO_FLOAT
  MRB_API mrb_value mrb_word_boxing_float_value(struct mrb_state*, mrb_float);
  #endif
  MRB_API mrb_value mrb_word_boxing_int_value(struct mrb_state*, mrb_int);
  
  #define mrb_immediate_p(o) ((o).w & WORDBOX_IMMEDIATE_MASK || (o).w == MRB_Qnil)
  
  #define mrb_ptr(o)     mrb_val_union(o).p
  #define mrb_cptr(o)    mrb_val_union(o).vp->p
  #ifndef MRB_NO_FLOAT
  #ifndef MRB_WORDBOX_USE_HEAP_FLOAT
  MRB_API mrb_float mrb_word_boxing_value_float(mrb_value v);
  #define mrb_float(o) mrb_word_boxing_value_float(o)
  #else
  #define mrb_float(o) mrb_val_union(o).fp->f
  #endif
  #endif
  #define mrb_fixnum(o)  (mrb_int)(((intptr_t)(o).w) >> WORDBOX_FIXNUM_SHIFT)
  MRB_INLINE mrb_int
  mrb_integer_func(mrb_value o) {
    if (mrb_immediate_p(o)) return mrb_fixnum(o);
    return mrb_val_union(o).ip->i;
  }
  #define mrb_integer(o) mrb_integer_func(o)
  #define mrb_symbol(o)  (mrb_sym)(((o).w) >> WORDBOX_SYMBOL_SHIFT)
  #define mrb_bool(o)    (((o).w & ~(uintptr_t)MRB_Qfalse) != 0)
  
  #define mrb_fixnum_p(o) WORDBOX_SHIFT_VALUE_P(o, FIXNUM)
  #define mrb_integer_p(o) (WORDBOX_SHIFT_VALUE_P(o, FIXNUM)||WORDBOX_OBJ_TYPE_P(o, INTEGER))
  #define mrb_symbol_p(o) WORDBOX_SHIFT_VALUE_P(o, SYMBOL)
  #define mrb_undef_p(o) ((o).w == MRB_Qundef)
  #define mrb_nil_p(o)  ((o).w == MRB_Qnil)
  #define mrb_false_p(o) ((o).w == MRB_Qfalse)
  #define mrb_true_p(o)  ((o).w == MRB_Qtrue)
  #ifndef MRB_NO_FLOAT
  #ifndef MRB_WORDBOX_USE_HEAP_FLOAT
  #define mrb_float_p(o) WORDBOX_SHIFT_VALUE_P(o, FLOAT)
  #else
  #define mrb_float_p(o) WORDBOX_OBJ_TYPE_P(o, FLOAT)
  #endif
  #endif
  #define mrb_array_p(o) WORDBOX_OBJ_TYPE_P(o, ARRAY)
  #define mrb_string_p(o) WORDBOX_OBJ_TYPE_P(o, STRING)
  #define mrb_hash_p(o) WORDBOX_OBJ_TYPE_P(o, HASH)
  #define mrb_cptr_p(o) WORDBOX_OBJ_TYPE_P(o, CPTR)
  #define mrb_exception_p(o) WORDBOX_OBJ_TYPE_P(o, EXCEPTION)
  #define mrb_free_p(o) WORDBOX_OBJ_TYPE_P(o, FREE)
  #define mrb_object_p(o) WORDBOX_OBJ_TYPE_P(o, OBJECT)
  #define mrb_class_p(o) WORDBOX_OBJ_TYPE_P(o, CLASS)
  #define mrb_module_p(o) WORDBOX_OBJ_TYPE_P(o, MODULE)
  #define mrb_iclass_p(o) WORDBOX_OBJ_TYPE_P(o, ICLASS)
  #define mrb_sclass_p(o) WORDBOX_OBJ_TYPE_P(o, SCLASS)
  #define mrb_proc_p(o) WORDBOX_OBJ_TYPE_P(o, PROC)
  #define mrb_range_p(o) WORDBOX_OBJ_TYPE_P(o, RANGE)
  #define mrb_env_p(o) WORDBOX_OBJ_TYPE_P(o, ENV)
  #define mrb_data_p(o) WORDBOX_OBJ_TYPE_P(o, DATA)
  #define mrb_fiber_p(o) WORDBOX_OBJ_TYPE_P(o, FIBER)
  #define mrb_istruct_p(o) WORDBOX_OBJ_TYPE_P(o, ISTRUCT)
  #define mrb_break_p(o) WORDBOX_OBJ_TYPE_P(o, BREAK)
  
  #ifndef MRB_NO_FLOAT
  #define SET_FLOAT_VALUE(mrb,r,v) ((r) = mrb_word_boxing_float_value(mrb, v))
  #endif
  #define SET_CPTR_VALUE(mrb,r,v) ((r) = mrb_word_boxing_cptr_value(mrb, v))
  #define SET_UNDEF_VALUE(r) ((r).w = MRB_Qundef)
  #define SET_NIL_VALUE(r) ((r).w = MRB_Qnil)
  #define SET_FALSE_VALUE(r) ((r).w = MRB_Qfalse)
  #define SET_TRUE_VALUE(r) ((r).w = MRB_Qtrue)
  #define SET_BOOL_VALUE(r,b) ((b) ? SET_TRUE_VALUE(r) : SET_FALSE_VALUE(r))
  #define SET_INT_VALUE(mrb,r,n) ((r) = mrb_word_boxing_int_value(mrb, n))
  #define SET_FIXNUM_VALUE(r,n) WORDBOX_SET_SHIFT_VALUE(r, FIXNUM, n)
  #define SET_SYM_VALUE(r,n) WORDBOX_SET_SHIFT_VALUE(r, SYMBOL, n)
  #define SET_OBJ_VALUE(r,v) ((r).w = (uintptr_t)(v))
  
  MRB_INLINE enum mrb_vtype
  mrb_type(mrb_value o)
  {
    return !mrb_bool(o)    ? MRB_TT_FALSE :
           mrb_true_p(o)   ? MRB_TT_TRUE :
           mrb_fixnum_p(o) ? MRB_TT_INTEGER :
           mrb_symbol_p(o) ? MRB_TT_SYMBOL :
           mrb_undef_p(o)  ? MRB_TT_UNDEF :
  #ifndef MRB_NO_FLOAT
           mrb_float_p(o)  ? MRB_TT_FLOAT :
  #endif
           mrb_val_union(o).bp->tt;
  }
  
  #endif  /* MRUBY_BOXING_WORD_H */
  