parse.y: calculate powers of ten

* parse.y (parser_yylex): calculate denominator directly as powers of
  ten, not parsing string.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@42334 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,4 +1,7 @@
-Fri Aug  2 23:14:54 2013  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+Fri Aug  2 23:48:36 2013  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* parse.y (parser_yylex): calculate denominator directly as powers of
+	  ten, not parsing string.
 
 	* parse.y (parser_number_literal_suffix): return bit set of found
 	  suffixes.

internal.h

@@ -503,6 +503,9 @@ VALUE rb_big_sq_fast(VALUE x);
 /* io.c */
 void rb_maygvl_fd_fix_cloexec(int fd);
 
+/* numeric.c */
+VALUE rb_int_positive_pow(long x, unsigned long y);
+
 /* process.c */
 int rb_exec_async_signal_safe(const struct rb_execarg *e, char *errmsg, size_t errmsg_buflen);
 rb_pid_t rb_fork_async_signal_safe(int *status, int (*chfunc)(void*, char *, size_t), void *charg, VALUE fds, char *errmsg, size_t errmsg_buflen);

numeric.c

@@ -2986,6 +2986,12 @@ int_pow(long x, unsigned long y)
     return LONG2NUM(z);
 }
 
+VALUE
+rb_int_positive_pow(long x, unsigned long y)
+{
+    return int_pow(x, y);
+}
+
 /*
  *  call-seq:
  *    fix ** numeric  ->  numeric_result

parse.y

@@ -7649,9 +7649,7 @@ parser_yylex(struct parser_params *parser)
 		    type = tRATIONAL;
 		    memmove(point, point+1, fraclen+1);
 		    v = rb_cstr_to_inum(tok(), 10, FALSE);
-		    *point = '1';
-		    memset(point+1, '0', fraclen);
-		    v = rb_rational_new(v, rb_cstr_to_inum(point, 10, FALSE));
+		    v = rb_rational_new(v, rb_int_positive_pow(10, fraclen));
 		}
 		else {
 		    double d = strtod(tok(), 0);