math/big: Add text marshaller interface to Int

Fixes #7329

LGTM=gri
R=gri, bradfitz, mtj
CC=golang-codereviews
https://golang.org/cl/63710043

diff --git a/src/pkg/math/big/int.go b/src/pkg/math/big/int.go
index 7bbb152d79cac16bc9cac3f3ca35a2f55306a19b..4591590d409817e6bf8b05af1be5674b6cd06c1a 100644 (file)
--- a/src/pkg/math/big/int.go
+++ b/src/pkg/math/big/int.go
@@ -982,17 +982,29 @@ func (z *Int) GobDecode(buf []byte) error {
 }
 
 // MarshalJSON implements the json.Marshaler interface.
-func (x *Int) MarshalJSON() ([]byte, error) {
+func (z *Int) MarshalJSON() ([]byte, error) {
        // TODO(gri): get rid of the []byte/string conversions
-       return []byte(x.String()), nil
+       return []byte(z.String()), nil
 }
 
 // UnmarshalJSON implements the json.Unmarshaler interface.
-func (z *Int) UnmarshalJSON(x []byte) error {
+func (z *Int) UnmarshalJSON(text []byte) error {
        // TODO(gri): get rid of the []byte/string conversions
-       _, ok := z.SetString(string(x), 0)
-       if !ok {
-               return fmt.Errorf("math/big: cannot unmarshal %s into a *big.Int", x)
+       if _, ok := z.SetString(string(text), 0); !ok {
+               return fmt.Errorf("math/big: cannot unmarshal %q into a *big.Int", text)
+       }
+       return nil
+}
+
+// MarshalText implements the encoding.TextMarshaler interface
+func (z *Int) MarshalText() (text []byte, err error) {
+       return []byte(z.String()), nil
+}
+
+// UnmarshalText implements the encoding.TextUnmarshaler interface
+func (z *Int) UnmarshalText(text []byte) error {
+       if _, ok := z.SetString(string(text), 0); !ok {
+               return fmt.Errorf("math/big: cannot unmarshal %q into a *big.Int", text)
        }
        return nil
 }

diff --git a/src/pkg/math/big/int_test.go b/src/pkg/math/big/int_test.go
index 87b975d5c4b6763170124918bdf6eb2c5857a9c9..3dd9c5b712b72d200d71e5e60846f37cb67a0f12 100644 (file)
--- a/src/pkg/math/big/int_test.go
+++ b/src/pkg/math/big/int_test.go
@@ -9,6 +9,7 @@ import (
        "encoding/gob"
        "encoding/hex"
        "encoding/json"
+       "encoding/xml"
        "fmt"
        "math/rand"
        "testing"
@@ -1528,6 +1529,58 @@ func TestIntJSONEncoding(t *testing.T) {
        }
 }
 
+var intVals = []string{
+       "-141592653589793238462643383279502884197169399375105820974944592307816406286",
+       "-1415926535897932384626433832795028841971",
+       "-141592653589793",
+       "-1",
+       "0",
+       "1",
+       "141592653589793",
+       "1415926535897932384626433832795028841971",
+       "141592653589793238462643383279502884197169399375105820974944592307816406286",
+}
+
+func TestIntJSONEncodingTextMarshaller(t *testing.T) {
+       for _, num := range intVals {
+               var tx Int
+               tx.SetString(num, 0)
+               b, err := json.Marshal(&tx)
+               if err != nil {
+                       t.Errorf("marshaling of %s failed: %s", &tx, err)
+                       continue
+               }
+               var rx Int
+               if err := json.Unmarshal(b, &rx); err != nil {
+                       t.Errorf("unmarshaling of %s failed: %s", &tx, err)
+                       continue
+               }
+               if rx.Cmp(&tx) != 0 {
+                       t.Errorf("JSON encoding of %s failed: got %s want %s", &tx, &rx, &tx)
+               }
+       }
+}
+
+func TestIntXMLEncodingTextMarshaller(t *testing.T) {
+       for _, num := range intVals {
+               var tx Int
+               tx.SetString(num, 0)
+               b, err := xml.Marshal(&tx)
+               if err != nil {
+                       t.Errorf("marshaling of %s failed: %s", &tx, err)
+                       continue
+               }
+               var rx Int
+               if err := xml.Unmarshal(b, &rx); err != nil {
+                       t.Errorf("unmarshaling of %s failed: %s", &tx, err)
+                       continue
+               }
+               if rx.Cmp(&tx) != 0 {
+                       t.Errorf("XML encoding of %s failed: got %s want %s", &tx, &rx, &tx)
+               }
+       }
+}
+
 func TestIssue2607(t *testing.T) {
        // This code sequence used to hang.
        n := NewInt(10)