Add strconv.Atob, Btoa.

Fixes issue 639

R=rsc
CC=golang-dev
http://codereview.appspot.com/755041

5 files changed, 94 insertions, 17 deletions

diff --git a/src/pkg/flag/flag.go b/src/pkg/flag/flag.go
index d57a59c03..e51bf7ddc 100644
--- a/src/pkg/flag/flag.go
+++ b/src/pkg/flag/flag.go
@@ -53,17 +53,6 @@ import (
 	"strconv"
 )
 
-// TODO(r): BUG: atob belongs elsewhere
-func atob(str string) (value bool, ok bool) {
-	switch str {
-	case "1", "t", "T", "true", "TRUE", "True":
-		return true, true
-	case "0", "f", "F", "false", "FALSE", "False":
-		return false, true
-	}
-	return false, false
-}
-
 // -- Bool Value
 type boolValue struct {
 	p *bool
@@ -75,9 +64,9 @@ func newBoolValue(val bool, p *bool) *boolValue {
 }
 
 func (b *boolValue) set(s string) bool {
-	v, ok := atob(s)
+	v, err := strconv.Atob(s)
 	*b.p = v
-	return ok
+	return err == nil
 }
 
 func (b *boolValue) String() string { return fmt.Sprintf("%v", *b.p) }
diff --git a/src/pkg/strconv/Makefile b/src/pkg/strconv/Makefile
index 8b20273b8..57849a821 100644
--- a/src/pkg/strconv/Makefile
+++ b/src/pkg/strconv/Makefile
@@ -6,6 +6,7 @@ include ../../Make.$(GOARCH)
 
 TARG=strconv
 GOFILES=\
+	atob.go\
 	atof.go\
 	atoi.go\
 	decimal.go\
diff --git a/src/pkg/strconv/atob.go b/src/pkg/strconv/atob.go
new file mode 100644
index 000000000..69fa2292a
--- /dev/null
+++ b/src/pkg/strconv/atob.go
@@ -0,0 +1,28 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package strconv
+
+import "os"
+
+// Atob returns the boolean value represented by the string.
+// It accepts 1, t, T, TRUE, true, 0, f, F, FALSE, false.  Any other value returns
+// an error.
+func Atob(str string) (value bool, err os.Error) {
+	switch str {
+	case "1", "t", "T", "true", "TRUE", "True":
+		return true, nil
+	case "0", "f", "F", "false", "FALSE", "False":
+		return false, nil
+	}
+	return false, &NumError{str, os.EINVAL}
+}
+
+// Btoa returns "true" or "false" according to the value of the boolean argument
+func Btoa(b bool) string {
+	if b {
+		return "true"
+	}
+	return "false"
+}
diff --git a/src/pkg/strconv/atob_test.go b/src/pkg/strconv/atob_test.go
new file mode 100644
index 000000000..ffad4b21b
--- /dev/null
+++ b/src/pkg/strconv/atob_test.go
@@ -0,0 +1,56 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package strconv_test
+
+import (
+	"os"
+	. "strconv"
+	"testing"
+)
+
+type atobTest struct {
+	in  string
+	out bool
+	err os.Error
+}
+
+var atobtests = []atobTest{
+	atobTest{"", false, os.EINVAL},
+	atobTest{"asdf", false, os.EINVAL},
+	atobTest{"0", false, nil},
+	atobTest{"f", false, nil},
+	atobTest{"F", false, nil},
+	atobTest{"FALSE", false, nil},
+	atobTest{"false", false, nil},
+	atobTest{"1", true, nil},
+	atobTest{"t", true, nil},
+	atobTest{"T", true, nil},
+	atobTest{"TRUE", true, nil},
+	atobTest{"true", true, nil},
+}
+
+func TestAtob(t *testing.T) {
+	for _, test := range atobtests {
+		b, e := Atob(test.in)
+		if test.err != nil {
+			// expect an error
+			if e == nil {
+				t.Errorf("%s: expected %s but got nil", test.in, test.err)
+			} else {
+				// NumError assertion must succeed; it's the only thing we return.
+				if test.err != e.(*NumError).Error {
+					t.Errorf("%s: expected %s but got %s", test.in, test.err, e)
+				}
+			}
+		} else {
+			if e != nil {
+				t.Errorf("%s: expected no error but got %s", test.in, test.err, e)
+			}
+			if b != test.out {
+				t.Errorf("%s: expected %t but got %t", test.in, test.out, b)
+			}
+		}
+	}
+}
diff --git a/src/pkg/xml/read.go b/src/pkg/xml/read.go
index dedf68944..e3ae2c402 100644
--- a/src/pkg/xml/read.go
+++ b/src/pkg/xml/read.go
@@ -105,8 +105,8 @@ import (
 // Unmarshal maps an XML element to a slice by extending the length
 // of the slice and mapping the element to the newly created value.
 //
-// Unmarshal maps an XML element to a bool by setting it true if the
-// string value is "true" or "1", or false otherwise.
+// Unmarshal maps an XML element to a bool by setting it to the boolean
+// value represented by the string.
 //
 // Unmarshal maps an XML element to an integer or floating-point
 // field by setting the field to the result of interpreting the string
@@ -473,8 +473,11 @@ Loop:
 		}
 		t.Set(ftmp)
 	case *reflect.BoolValue:
-		btmp := strings.TrimSpace(string(data))
-		t.Set(strings.ToLower(btmp) == "true" || btmp == "1")
+		value, err := strconv.Atob(strings.TrimSpace(string(data)))
+		if err != nil {
+			return err
+		}
+		t.Set(value)
 	case *reflect.StringValue:
 		t.Set(string(data))
 	case *reflect.SliceValue: