better object_id calculation

src/etc.c

@@ -126,89 +126,48 @@ mrb_block_proc(void)
   return mrb_nil_value();//proc_new(mrb_cProc, FALSE);
 }
 
+#include <stdio.h>
+static mrb_int
+float_id(mrb_float f)
+{
+  const char *p = (const char*)&f;
+  int len = sizeof(f);
+  mrb_int id = 0;
+
+  while (len--) {
+    id = id*65599 + *p;
+    p++;
+  }
+  id = id + (id>>5);
+
+  return id;
+}
+
 mrb_int
 mrb_obj_id(mrb_value obj)
 {
-    /*
-     *                32-bit mrb_value space
-     *          MSB ------------------------ LSB
-     *  false   00000000000000000000000000000000
-     *  true    00000000000000000000000000000010
-     *  nil     00000000000000000000000000000100
-     *  undef   00000000000000000000000000000110
-     *  symbol  ssssssssssssssssssssssss00001110
-     *  object  oooooooooooooooooooooooooooooo00        = 0 (mod sizeof(RVALUE))
-     *  fixnum  fffffffffffffffffffffffffffffff1
-     *
-     *                    object_id space
-     *                                       LSB
-     *  false   00000000000000000000000000000000
-     *  true    00000000000000000000000000000010
-     *  nil     00000000000000000000000000000100
-     *  undef   00000000000000000000000000000110
-     *  symbol   000SSSSSSSSSSSSSSSSSSSSSSSSSSS0        S...S % A = 4 (S...S = s...s * A + 4)
-     *  object   oooooooooooooooooooooooooooooo0        o...o % A = 0
-     *  fixnum  fffffffffffffffffffffffffffffff1        bignum if required
-     *
-     *  where A = sizeof(RVALUE)/4
-     *
-     *  sizeof(RVALUE) is
-     *  20 if 32-bit, double is 4-byte aligned
-     *  24 if 32-bit, double is 8-byte aligned
-     *  40 if 64-bit
-     */
-    /*
-     *                128-bit mrb_value space
-     *          MSB -------- LSB
-     *  x86           [0,1]             [2,3]            [4,5]            [6,7]            [8,9]            [A,B]            [C,D]            [E,F]
-     *          7                6                5                4                3                2                1                0
-     *          0123456789ABCDEF 0123456789ABCDEF 0123456789ABCDEF 0123456789ABCDEF 0123456789ABCDEF 0123456789ABCDEF 0123456789ABCDEF 0123456789ABCDEF
-     *          FEDCBA9876543210 FEDCBA9876543210 FEDCBA9876543210 FEDCBA9876543210 FEDCBA9876543210 FEDCBA9876543210 FEDCBA9876543210 FEDCBA9876543210
-     *  false   0000000000000000 0000000000000000 xxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxx xxxxxxxx00000001 xxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxx
-     *  true    0000000000000001 0000000000000000 xxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxx xxxxxxxx00000010 xxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxx
-     *  nil     0000000000000001 0000000000000000 xxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxx xxxxxxxx00000001 xxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxx
-     *  undef   0000000000000000 0000000000000000 xxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxx xxxxxxxx00000101 xxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxx
-     *  symbol  ssssssssssssssss ssssssssssssssss xxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxx xxxxxxxx00000100 xxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxx
-     *  object  oooooooooooooooo oooooooooooooo00        = 0 (mod sizeof(RVALUE))
-     (1)fixnum  0000000000000001 0000000000000000 xxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxx xxxxxxxx00000011 xxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxx
-     *  float   0000000000000001 0000000000000000 0000000000000000 0000000000000000 xxxxxxxx00000011 xxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxx
-     *          <--                          mrb_float                          --> xxxxxxxx00001101 xxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxx
-     *
-     *                    object_id space
-     *                                       LSB
-     *  false   0000000000000000 0000000000000000
-     *  true    0000000000000000 0000000000000010
-     *  nil     0000000000000000 0000000000000100
-     *  undef   0000000000000000 0000000000000110
-     *  symbol  000SSSSSSSSSSSS SSSSSSSSSSSSSSS0        S...S % A = 4 (S...S = s...s * A + 4)
-     *  object  ooooooooooooooo ooooooooooooooo0        o...o % A = 0
-     *  fixnum  ffffffffffffffff fffffffffffffff1        bignum if required
-     *
-     *  where A = sizeof(RVALUE)/4
-     *
-     *  sizeof(RVALUE) is
-     *  20 if 32-bit, double is 4-byte aligned
-     *  24 if 32-bit, double is 8-byte aligned
-     *  40 if 64-bit
-     */
-    /* tt:0_27 */
-  switch (mrb_type(obj)) {
+  mrb_int tt = obj.tt;
+
+#define MakeID2(p,t) (((intptr_t)(p))^(t))
+#define MakeID(p)    MakeID2(p,tt)
+
+  switch (tt) {
   case  MRB_TT_FREE:
-      return 0; /* not define */
+  case  MRB_TT_UNDEF:
+    return MakeID(0); /* not define */
   case  MRB_TT_FALSE:
     if (mrb_nil_p(obj))
-        return 4;
-      return 0;
+      return MakeID(1);
+    return MakeID(0);
   case  MRB_TT_TRUE:
-      return 2;
-    case  MRB_TT_FIXNUM:
-      return mrb_fixnum(obj)*2+1; /* odd number */
+    return MakeID(1);
   case  MRB_TT_SYMBOL:
-      return SYM2ID(obj) * 2;
-    case  MRB_TT_UNDEF:
-      return 0; /* not define */
+    return MakeID(SYM2ID(obj));
+  case  MRB_TT_FIXNUM:
+    return MakeID2(float_id((mrb_float)mrb_fixnum(obj)), MRB_TT_FLOAT);
   case  MRB_TT_FLOAT:
-      return (int)mrb_float(obj)*2; /* even number */
+    return MakeID(float_id(mrb_float(obj)));
+  case  MRB_TT_STRING:
   case  MRB_TT_OBJECT:
   case  MRB_TT_CLASS:
   case  MRB_TT_MODULE:
@@ -217,7 +176,6 @@ mrb_obj_id(mrb_value obj)
   case  MRB_TT_PROC:
   case  MRB_TT_ARRAY:
   case  MRB_TT_HASH:
-    case  MRB_TT_STRING:
   case  MRB_TT_RANGE:
   case  MRB_TT_REGEX:
   case  MRB_TT_STRUCT:
@@ -228,7 +186,7 @@ mrb_obj_id(mrb_value obj)
   case  MRB_TT_THREAD:
   case  MRB_TT_THREADGRP:
   default:
-      return mrb_fixnum(obj); /* even number */
+    return MakeID(obj.value.p);
   }
 }