* bignum.c (calc_hbase): Make hbase the maximum power of base

representable in BDIGIT.



git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@41006 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,8 @@
+Sat Jun  1 00:19:50 2013  Tanaka Akira  <akr@fsij.org>
+
+	* bignum.c (calc_hbase): Make hbase the maximum power of base
+	  representable in BDIGIT.
+
 Fri May 31 23:56:13 2013  Tanaka Akira  <akr@fsij.org>
 
 	* bignum.c (calc_hbase): Extracted from rb_big2str0.

bignum.c

@@ -1125,12 +1125,12 @@ calc_hbase(int base, long *hbase_p, int *hbase_numdigits_p)
     long hbase;
     int hbase_numdigits;
 
-    hbase = base*base;
-    hbase_numdigits = 2;
-#if SIZEOF_BDIGITS > 2
-    hbase *= hbase;
-    hbase_numdigits *= 2;
-#endif
+    hbase = base;
+    hbase_numdigits = 1;
+    while (hbase <= (~(BDIGIT)0) / base) {
+        hbase *= base;
+        hbase_numdigits++;
+    }
 
     *hbase_p = hbase;
     *hbase_numdigits_p = hbase_numdigits;