diff options
| -rw-r--r-- | ChangeLog | 5 | ||||
| -rw-r--r-- | numeric.c | 8 |
2 files changed, 10 insertions, 3 deletions
@@ -1,3 +1,8 @@ +Thu Mar 5 18:36:38 2009 Nobuyoshi Nakada <nobu@ruby-lang.org> + + * numeric.c (flo_to_s): keeps enough precision for round trip. + [ruby-core:22325] + Thu Mar 5 16:56:14 2009 Nobuyoshi Nakada <nobu@ruby-lang.org> * lib/tmpdir.rb (Dir.tmpdir): not use USERPROFILE, and ignores @@ -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); } |