encoding/binary: add bool support

This change adds support for decoding and encoding the bool type. The
encoding is a single byte, with a zero value for false and a non-zero
value for true.

Closes #16856.

Change-Id: I1d1114b320263691473bb100cad0f380e0204186
Reviewed-on: https://go-review.googlesource.com/28514
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>

1 files changed, 51 insertions, 3 deletions

diff --git a/src/encoding/binary/binary.go b/src/encoding/binary/binary.go
index 46c6add062..fd360a2e54 100644
--- a/src/encoding/binary/binary.go
+++ b/src/encoding/binary/binary.go
@@ -169,6 +169,8 @@ func Read(r io.Reader, order ByteOrder, data interface{}) error {
 			return err
 		}
 		switch data := data.(type) {
+		case *bool:
+			*data = b[0] != 0
 		case *int8:
 			*data = int8(b[0])
 		case *uint8:
@@ -185,8 +187,12 @@ func Read(r io.Reader, order ByteOrder, data interface{}) error {
 			*data = int64(order.Uint64(bs))
 		case *uint64:
 			*data = order.Uint64(bs)
-		case []int8:
+		case []bool:
 			for i, x := range bs { // Easier to loop over the input for 8-bit values.
+				data[i] = x != 0
+			}
+		case []int8:
+			for i, x := range bs {
 				data[i] = int8(x)
 			}
 		case []uint8:
@@ -258,6 +264,26 @@ func Write(w io.Writer, order ByteOrder, data interface{}) error {
 			bs = b[:n]
 		}
 		switch v := data.(type) {
+		case *bool:
+			if *v {
+				b[0] = 1
+			} else {
+				b[0] = 0
+			}
+		case bool:
+			if v {
+				b[0] = 1
+			} else {
+				b[0] = 0
+			}
+		case []bool:
+			for i, x := range v {
+				if x {
+					bs[i] = 1
+				} else {
+					bs[i] = 0
+				}
+			}
 		case *int8:
 			b[0] = byte(*v)
 		case int8:
@@ -378,7 +404,8 @@ func sizeof(t reflect.Type) int {
 		}
 		return sum
 
-	case reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64,
+	case reflect.Bool,
+		reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64,
 		reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64,
 		reflect.Float32, reflect.Float64, reflect.Complex64, reflect.Complex128:
 		return int(t.Size())
@@ -395,6 +422,21 @@ type coder struct {
 type decoder coder
 type encoder coder
 
+func (d *decoder) bool() bool {
+	x := d.buf[0]
+	d.buf = d.buf[1:]
+	return x != 0
+}
+
+func (e *encoder) bool(x bool) {
+	if x {
+		e.buf[0] = 1
+	} else {
+		e.buf[0] = 0
+	}
+	e.buf = e.buf[1:]
+}
+
 func (d *decoder) uint8() uint8 {
 	x := d.buf[0]
 	d.buf = d.buf[1:]
@@ -485,6 +527,9 @@ func (d *decoder) value(v reflect.Value) {
 			d.value(v.Index(i))
 		}
 
+	case reflect.Bool:
+		v.SetBool(d.bool())
+
 	case reflect.Int8:
 		v.SetInt(int64(d.int8()))
 	case reflect.Int16:
@@ -547,6 +592,9 @@ func (e *encoder) value(v reflect.Value) {
 			e.value(v.Index(i))
 		}
 
+	case reflect.Bool:
+		e.bool(v.Bool())
+
 	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
 		switch v.Type().Kind() {
 		case reflect.Int8:
@@ -609,7 +657,7 @@ func (e *encoder) skip(v reflect.Value) {
 // It returns zero if the type cannot be implemented by the fast path in Read or Write.
 func intDataSize(data interface{}) int {
 	switch data := data.(type) {
-	case int8, uint8, *int8, *uint8:
+	case bool, int8, uint8, *bool, *int8, *uint8:
 		return 1
 	case []int8:
 		return len(data)