From 101e79d7b434c01c0e6f4bcc480003858ab8e1a4 Mon Sep 17 00:00:00 2001 From: nobu Date: Thu, 5 Mar 2009 09:36:39 +0000 Subject: * numeric.c (flo_to_s): keeps enough precision for round trip. [ruby-core:22325] git-svn-id: http://svn.ruby-lang.org/repos/ruby/trunk@22783 b2dd03c8-39d4-4d8f-98ff-823fe69b080e --- numeric.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) (limited to 'numeric.c') diff --git a/numeric.c b/numeric.c index 2d6691de6..bb5548566 100644 --- a/numeric.c +++ b/numeric.c @@ -521,7 +521,9 @@ rb_float_new(double d) static VALUE flo_to_s(VALUE flt) { - char buf[32]; + enum {decimal_mant = DBL_MANT_DIG-DBL_DIG}; + enum {float_dig = DBL_DIG+2}; + char buf[float_dig + (decimal_mant + CHAR_BIT - 1) / CHAR_BIT + 10]; double value = RFLOAT_VALUE(flt); char *p, *e; @@ -530,12 +532,12 @@ flo_to_s(VALUE flt) else if(isnan(value)) return rb_usascii_str_new2("NaN"); - snprintf(buf, sizeof(buf), "%#.15g", value); /* ensure to print decimal point */ + snprintf(buf, sizeof(buf), "%#.*g", float_dig, value); /* ensure to print decimal point */ if (!(e = strchr(buf, 'e'))) { e = buf + strlen(buf); } if (!ISDIGIT(e[-1])) { /* reformat if ended with decimal point (ex 111111111111111.) */ - snprintf(buf, sizeof(buf), "%#.14e", value); + snprintf(buf, sizeof(buf), "%#.*e", float_dig - 1, value); if (!(e = strchr(buf, 'e'))) { e = buf + strlen(buf); } -- cgit