math/big: implement JSON un/marshaling support for Ints
Also: simplified some existing tests.
No support for Rats for now because the precision-preserving
default notation (fractions of the form a/b) is not a valid
JSON value.
Fixes #3657.
R=golang-dev, bradfitz, rsc
CC=golang-dev
https://golang.org/cl/6211079
diff --git a/src/pkg/math/big/int.go b/src/pkg/math/big/int.go
index cd2cd0e..ce308bd 100644
--- a/src/pkg/math/big/int.go
+++ b/src/pkg/math/big/int.go
@@ -894,3 +894,19 @@
z.abs = z.abs.setBytes(buf[1:])
return nil
}
+
+// MarshalJSON implements the json.Marshaler interface.
+func (x *Int) MarshalJSON() ([]byte, error) {
+ // TODO(gri): get rid of the []byte/string conversions
+ return []byte(x.String()), nil
+}
+
+// UnmarshalJSON implements the json.Unmarshaler interface.
+func (z *Int) UnmarshalJSON(x []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)
+ }
+ return nil
+}
diff --git a/src/pkg/math/big/int_test.go b/src/pkg/math/big/int_test.go
index 9700a9b..30e5591 100644
--- a/src/pkg/math/big/int_test.go
+++ b/src/pkg/math/big/int_test.go
@@ -8,6 +8,7 @@
"bytes"
"encoding/gob"
"encoding/hex"
+ "encoding/json"
"fmt"
"math/rand"
"testing"
@@ -1368,8 +1369,12 @@
}
}
-// used by TestIntGobEncoding and TestRatGobEncoding
-var gobEncodingTests = []string{
+var encodingTests = []string{
+ "-539345864568634858364538753846587364875430589374589",
+ "-678645873",
+ "-100",
+ "-2",
+ "-1",
"0",
"1",
"2",
@@ -1383,26 +1388,37 @@
var medium bytes.Buffer
enc := gob.NewEncoder(&medium)
dec := gob.NewDecoder(&medium)
- for i, test := range gobEncodingTests {
- for j := 0; j < 2; j++ {
- medium.Reset() // empty buffer for each test case (in case of failures)
- stest := test
- if j != 0 {
- // negative numbers
- stest = "-" + test
- }
- var tx Int
- tx.SetString(stest, 10)
- if err := enc.Encode(&tx); err != nil {
- t.Errorf("#%d%c: encoding failed: %s", i, 'a'+j, err)
- }
- var rx Int
- if err := dec.Decode(&rx); err != nil {
- t.Errorf("#%d%c: decoding failed: %s", i, 'a'+j, err)
- }
- if rx.Cmp(&tx) != 0 {
- t.Errorf("#%d%c: transmission failed: got %s want %s", i, 'a'+j, &rx, &tx)
- }
+ for _, test := range encodingTests {
+ medium.Reset() // empty buffer for each test case (in case of failures)
+ var tx Int
+ tx.SetString(test, 10)
+ if err := enc.Encode(&tx); err != nil {
+ t.Errorf("encoding of %s failed: %s", &tx, err)
+ }
+ var rx Int
+ if err := dec.Decode(&rx); err != nil {
+ t.Errorf("decoding of %s failed: %s", &tx, err)
+ }
+ if rx.Cmp(&tx) != 0 {
+ t.Errorf("transmission of %s failed: got %s want %s", &tx, &rx, &tx)
+ }
+ }
+}
+
+func TestIntJSONEncoding(t *testing.T) {
+ for _, test := range encodingTests {
+ var tx Int
+ tx.SetString(test, 10)
+ b, err := json.Marshal(&tx)
+ if err != nil {
+ t.Errorf("marshaling of %s failed: %s", &tx, err)
+ }
+ var rx Int
+ if err := json.Unmarshal(b, &rx); err != nil {
+ t.Errorf("unmarshaling of %s failed: %s", &tx, err)
+ }
+ if rx.Cmp(&tx) != 0 {
+ t.Errorf("JSON encoding of %s failed: got %s want %s", &tx, &rx, &tx)
}
}
}
diff --git a/src/pkg/math/big/rat_test.go b/src/pkg/math/big/rat_test.go
index f7f31ae..fbeb596 100644
--- a/src/pkg/math/big/rat_test.go
+++ b/src/pkg/math/big/rat_test.go
@@ -387,30 +387,19 @@
var medium bytes.Buffer
enc := gob.NewEncoder(&medium)
dec := gob.NewDecoder(&medium)
- for i, test := range gobEncodingTests {
- for j := 0; j < 4; j++ {
- medium.Reset() // empty buffer for each test case (in case of failures)
- stest := test
- if j&1 != 0 {
- // negative numbers
- stest = "-" + test
- }
- if j%2 != 0 {
- // fractions
- stest = stest + "." + test
- }
- var tx Rat
- tx.SetString(stest)
- if err := enc.Encode(&tx); err != nil {
- t.Errorf("#%d%c: encoding failed: %s", i, 'a'+j, err)
- }
- var rx Rat
- if err := dec.Decode(&rx); err != nil {
- t.Errorf("#%d%c: decoding failed: %s", i, 'a'+j, err)
- }
- if rx.Cmp(&tx) != 0 {
- t.Errorf("#%d%c: transmission failed: got %s want %s", i, 'a'+j, &rx, &tx)
- }
+ for _, test := range encodingTests {
+ medium.Reset() // empty buffer for each test case (in case of failures)
+ var tx Rat
+ tx.SetString(test + ".14159265")
+ if err := enc.Encode(&tx); err != nil {
+ t.Errorf("encoding of %s failed: %s", &tx, err)
+ }
+ var rx Rat
+ if err := dec.Decode(&rx); err != nil {
+ t.Errorf("decoding of %s failed: %s", &tx, err)
+ }
+ if rx.Cmp(&tx) != 0 {
+ t.Errorf("transmission of %s failed: got %s want %s", &tx, &rx, &tx)
}
}
}
