From: Tadayoshi Funaba <tadf@...>
Date: 2009-06-15T22:30:15+09:00
Subject: [ruby-dev:38637] Re: Fixnum#fdiv

後者の考えに基いて修正してみました。

Inf.fdiv(Float::MAX.to_i*2)
などの場合も対処しないといけないと思いますが、とりあえず。


Index: complex.c
===================================================================
--- complex.c	(revision 23694)
+++ complex.c	(working copy)
@@ -660,6 +660,7 @@
 static VALUE
 nucomp_fdiv(VALUE self, VALUE other)
 {
+    rb_warning("Complex#fdiv will be deprecated in the future");
     return nucomp_divide(self, other, f_fdiv, id_fdiv);
 }
 
Index: bignum.c
===================================================================
--- bignum.c	(revision 23694)
+++ bignum.c	(working copy)
@@ -2382,6 +2382,53 @@
     return x;
 }
 
+static VALUE 
+big_fdiv(VALUE x, VALUE y)
+{
+#define DBL_BIGDIG ((DBL_MANT_DIG + BITSPERDIG) / BITSPERDIG)
+    VALUE z;
+    long l, ex, ey;
+    int i;
+
+    bigtrunc(x);
+    l = RBIGNUM_LEN(x) - 1;
+    ex = l * BITSPERDIG;
+    ex += bdigbitsize(BDIGITS(x)[l]);
+    ex -= 2 * DBL_BIGDIG * BITSPERDIG;
+    if (ex) x = big_shift(x, ex);
+
+    switch (TYPE(y)) {
+      case T_FIXNUM:
+	y = rb_int2big(FIX2LONG(y));
+      case T_BIGNUM: {
+	  bigtrunc(y);
+	  l = RBIGNUM_LEN(y) - 1;
+	  ey = l * BITSPERDIG;
+	  ey += bdigbitsize(BDIGITS(y)[l]);
+	  ey -= DBL_BIGDIG * BITSPERDIG;
+	  if (ey) y = big_shift(y, ey);
+	  bignum:
+	  bigdivrem(x, y, &z, 0);
+	  l = ex - ey;
+#if SIZEOF_LONG > SIZEOF_INT
+	  {
+	      /* Visual C++ can't be here */
+	      if (l > INT_MAX) return DBL2NUM(ruby_div0(1.0));
+	      if (l < INT_MIN) return DBL2NUM(0.0);
+	  }
+#endif
+	  return DBL2NUM(ldexp(big2dbl(z), (int)l));
+      }
+      case T_FLOAT:
+	y = dbl2big(ldexp(frexp(RFLOAT_VALUE(y), &i), DBL_MANT_DIG));
+	ey = i - DBL_MANT_DIG;
+	goto bignum;
+    }
+    /* NOTREACHED */
+    abort();
+    return Qnil;
+}
+
 /*
  *  call-seq:
   *     big.fdiv(numeric) -> float
@@ -2394,65 +2441,32 @@
  *
  */
 
-static VALUE
+
+VALUE
 rb_big_fdiv(VALUE x, VALUE y)
 {
-    double dx = big2dbl(x);
-    double dy;
+    double dx, dy;
 
-    if (isinf(dx)) {
-#define DBL_BIGDIG ((DBL_MANT_DIG + BITSPERDIG) / BITSPERDIG)
-	VALUE z;
-	long l, ex, ey;
-	int i;
-
-	bigtrunc(x);
-	l = RBIGNUM_LEN(x) - 1;
-	ex = l * BITSPERDIG;
-	ex += bdigbitsize(BDIGITS(x)[l]);
-	ex -= 2 * DBL_BIGDIG * BITSPERDIG;
-	if (ex) x = big_shift(x, ex);
-
-	switch (TYPE(y)) {
-	  case T_FIXNUM:
-	    y = rb_int2big(FIX2LONG(y));
-	  case T_BIGNUM: {
-	    bigtrunc(y);
-	    l = RBIGNUM_LEN(y) - 1;
-	    ey = l * BITSPERDIG;
-	    ey += bdigbitsize(BDIGITS(y)[l]);
-	    ey -= DBL_BIGDIG * BITSPERDIG;
-	    if (ey) y = big_shift(y, ey);
-	  bignum:
-	    bigdivrem(x, y, &z, 0);
-	    l = ex - ey;
-#if SIZEOF_LONG > SIZEOF_INT
-	    {
-		/* Visual C++ can't be here */
-		if (l > INT_MAX) return DBL2NUM(ruby_div0(1.0));
-		if (l < INT_MIN) return DBL2NUM(0.0);
-	    }
-#endif
-	    return DBL2NUM(ldexp(big2dbl(z), (int)l));
-	  }
-	  case T_FLOAT:
-	    if (isnan(RFLOAT_VALUE(y))) return y;
-	    y = dbl2big(ldexp(frexp(RFLOAT_VALUE(y), &i), DBL_MANT_DIG));
-	    ey = i - DBL_MANT_DIG;
-	    goto bignum;
-	}
-    }
+    dx = big2dbl(x);
     switch (TYPE(y)) {
       case T_FIXNUM:
 	dy = (double)FIX2LONG(y);
+	if (isinf(dx))
+	    return big_fdiv(x, y);
 	break;
 
       case T_BIGNUM:
 	dy = rb_big2dbl(y);
+	if (isinf(dx) || isinf(dy))
+	    return big_fdiv(x, y);
 	break;
 
       case T_FLOAT:
 	dy = RFLOAT_VALUE(y);
+	if (isnan(dy))
+	    return y;
+	if (isinf(dx))
+	    return big_fdiv(x, y);
 	break;
 
       default:
Index: rational.c
===================================================================
--- rational.c	(revision 23694)
+++ rational.c	(working copy)
@@ -769,7 +769,7 @@
 static VALUE
 nurat_fdiv(VALUE self, VALUE other)
 {
-    return f_div(f_to_f(self), other);
+    return f_to_f(f_div(self, other));
 }
 
 static VALUE