math/big: fix %b format so it matches strconf %b format for non-zero values
(For zero values the strconv %b format prints the bias-adjusted exponent;
there's no bias in Float.)
Change-Id: I6f4dda9c3a50d02eac375cfe2c927c1540aae865
Reviewed-on: https://go-review.googlesource.com/3841
Reviewed-by: Alan Donovan <adonovan@google.com>
diff --git a/src/math/big/floatconv_test.go b/src/math/big/floatconv_test.go
index 83ea1d6..0e8bfb3 100644
--- a/src/math/big/floatconv_test.go
+++ b/src/math/big/floatconv_test.go
@@ -9,55 +9,53 @@
"testing"
)
-var floatSetFloat64StringTests = []struct {
- s string
- x float64
-}{
- {"0", 0},
- {"-0", -0},
- {"+0", 0},
- {"1", 1},
- {"-1", -1},
- {"+1", 1},
- {"1.234", 1.234},
- {"-1.234", -1.234},
- {"+1.234", 1.234},
- {".1", 0.1},
- {"1.", 1},
- {"+1.", 1},
-
- {"0e100", 0},
- {"-0e+100", 0},
- {"+0e-100", 0},
- {"0E100", 0},
- {"-0E+100", 0},
- {"+0E-100", 0},
- {"0p100", 0},
- {"-0p+100", 0},
- {"+0p-100", 0},
-
- {"1.e10", 1e10},
- {"1e+10", 1e10},
- {"+1e-10", 1e-10},
- {"1E10", 1e10},
- {"1.E+10", 1e10},
- {"+1E-10", 1e-10},
- {"1p10", 1 << 10},
- {"1p+10", 1 << 10},
- {"+1.p-10", 1.0 / (1 << 10)},
-
- {"-687436.79457e-245", -687436.79457e-245},
- {"-687436.79457E245", -687436.79457e245},
- {"1024.p-12", 0.25},
- {"-1.p10", -1024},
- {"0.25p2", 1},
-
- {".0000000000000000000000000000000000000001", 1e-40},
- {"+10000000000000000000000000000000000000000e-0", 1e40},
-}
-
func TestFloatSetFloat64String(t *testing.T) {
- for _, test := range floatSetFloat64StringTests {
+ for _, test := range []struct {
+ s string
+ x float64
+ }{
+ {"0", 0},
+ {"-0", -0},
+ {"+0", 0},
+ {"1", 1},
+ {"-1", -1},
+ {"+1", 1},
+ {"1.234", 1.234},
+ {"-1.234", -1.234},
+ {"+1.234", 1.234},
+ {".1", 0.1},
+ {"1.", 1},
+ {"+1.", 1},
+
+ {"0e100", 0},
+ {"-0e+100", 0},
+ {"+0e-100", 0},
+ {"0E100", 0},
+ {"-0E+100", 0},
+ {"+0E-100", 0},
+ {"0p100", 0},
+ {"-0p+100", 0},
+ {"+0p-100", 0},
+
+ {"1.e10", 1e10},
+ {"1e+10", 1e10},
+ {"+1e-10", 1e-10},
+ {"1E10", 1e10},
+ {"1.E+10", 1e10},
+ {"+1E-10", 1e-10},
+ {"1p10", 1 << 10},
+ {"1p+10", 1 << 10},
+ {"+1.p-10", 1.0 / (1 << 10)},
+
+ {"-687436.79457e-245", -687436.79457e-245},
+ {"-687436.79457E245", -687436.79457e245},
+ {"1024.p-12", 0.25},
+ {"-1.p10", -1024},
+ {"0.25p2", 1},
+
+ {".0000000000000000000000000000000000000001", 1e-40},
+ {"+10000000000000000000000000000000000000000e-0", 1e40},
+ } {
var x Float
x.prec = 53 // TODO(gri) find better solution
_, ok := x.SetString(test.s)
@@ -82,8 +80,9 @@
}{
{"0", 'b', 0, "0"},
{"-0", 'b', 0, "-0"},
- {"1.0", 'b', 0, "4503599627370496p1"},
- {"-1.0", 'b', 0, "-4503599627370496p1"},
+ {"1.0", 'b', 0, "4503599627370496p-52"},
+ {"-1.0", 'b', 0, "-4503599627370496p-52"},
+ {"4503599627370496", 'b', 0, "4503599627370496p+0"},
{"0", 'p', 0, "0"},
{"-0", 'p', 0, "-0"},
@@ -95,14 +94,21 @@
t.Error(err)
continue
}
+
f := new(Float).SetFloat64(f64)
got := f.Format(test.format, test.prec)
if got != test.want {
- t.Errorf("%v: got %s", test, got)
+ t.Errorf("%v: got %s; want %s", test, got, test.want)
}
- if test.format == 'b' || test.format == 'p' {
- continue // 'b', 'p' format not supported or different in strconv.Format
+
+ if test.format == 'b' && f64 == 0 {
+ continue // 'b' format in strconv.Float requires knowledge of bias for 0.0
}
+ if test.format == 'p' {
+ continue // 'p' format not supported in strconv.Format
+ }
+
+ // verify that Float format matches strconv format
want := strconv.FormatFloat(f64, test.format, test.prec, 64)
if got != want {
t.Errorf("%v: got %s; want %s", test, got, want)
