Sort map keys before converting from Value to Json #21.

Author: prataprc

cbor.go

@@ -122,7 +122,8 @@ var hdrIndefiniteText = cborHdr(cborType3, cborIndefiniteLength)
 var hdrIndefiniteArray = cborHdr(cborType4, cborIndefiniteLength)
 var hdrIndefiniteMap = cborHdr(cborType5, cborIndefiniteLength)
 
-// Cbor encapsulates configuration and a cbor buffer.
+// Cbor encapsulates configuration and a cbor buffer. Map element
+// in cbor encoding should have its keys sorted.
 type Cbor struct {
 	config *Config
 	data   []byte

config_test.go

@@ -163,6 +163,36 @@ func TestContainerEncodingString(t *testing.T) {
 	}
 }
 
+func TestCheckSortedkeys(t *testing.T) {
+	val := map[string]interface{}{
+		"ddd": true, "ccc": false, "fff": true, "aaa": nil,
+		"bbb": []interface{}{1, 2},
+	}
+	srtjson := `{"aaa":null,"bbb":[1,2],"ccc":false,"ddd":true,"fff":true}`
+
+	config := NewDefaultConfig()
+	jsn := config.NewJson(make([]byte, 1024), 0)
+	cbr := config.NewCbor(make([]byte, 1024), 0)
+	col := config.NewCollate(make([]byte, 1024), 0)
+
+	json := config.NewValue(val).Tojson(jsn.Reset(nil)).Bytes()
+	if string(json) != srtjson {
+		t.Errorf("expected %v, got %v", srtjson, string(json))
+	}
+
+	cbr = config.NewValue(val).Tocbor(cbr.Reset(nil))
+	json = cbr.Tojson(jsn.Reset(nil)).Bytes()
+	if string(json) != srtjson {
+		t.Errorf("expected %v, got %v", srtjson, string(json))
+	}
+
+	col = config.NewValue(val).Tocollate(col.Reset(nil))
+	json = col.Tocbor(cbr.Reset(nil)).Tojson(jsn.Reset(nil)).Bytes()
+	if string(json) != srtjson {
+		t.Errorf("expected %v, got %v", srtjson, string(json))
+	}
+}
+
 func testdataFile(filename string) []byte {
 	f, err := os.Open(filename)
 	if err != nil {

util.go

@@ -290,15 +290,29 @@ func collated2Json(code []byte, text []byte, nk NumberKind) int {
 }
 
 // sort JSON property objects based on property names.
-func sortProps(props map[string]interface{}, keys []string) []string {
+func sortProps1(props map[string]interface{}, keys []string) []string {
 	for k := range props {
 		keys = append(keys, k)
 	}
 
 	return sortStrings(keys)
 }
 
-// bubble sort, moving to qsort should be atleast 40% faster.
+func sortProps2(props map[string]uint64, keys []string) []string {
+	for k := range props {
+		keys = append(keys, k)
+	}
+	return sortStrings(keys)
+}
+
+func sortProps3(props [][2]interface{}, keys []string) []string {
+	for _, item := range props {
+		keys = append(keys, item[0].(string))
+	}
+	return sortStrings(keys)
+}
+
+// TODO: bubble sort, moving to qsort should be atleast 40% faster.
 func sortStrings(strs []string) []string {
 	for ln := len(strs) - 1; ; ln-- {
 		changed := false

value_cbor.go

@@ -70,16 +70,22 @@ func value2cbor(item interface{}, out []byte, config *Config) int {
 	case [][2]interface{}:
 		n += valmap2cbor(v, out, config)
 	case map[string]interface{}:
+		poolobj := config.pools.keysPool.Get()
+		keys := poolobj.([]string)
+		defer config.pools.keysPool.Put(poolobj)
+
 		if config.ct == LengthPrefix {
 			n += valuint642cbor(uint64(len(v)), out[n:])
 			out[n-1] = (out[n-1] & 0x1f) | cborType5 // fix the type
-			for key, value := range v {
+			for _, key := range sortProps1(v, keys) {
+				value := v[key]
 				n += valtext2cbor(key, out[n:])
 				n += value2cbor(value, out[n:], config)
 			}
 		} else if config.ct == Stream {
 			n += mapStart(out[n:])
-			for key, value := range v {
+			for _, key := range sortProps1(v, keys) {
+				value := v[key]
 				n += valtext2cbor(key, out[n:])
 				n += value2cbor(value, out[n:], config)
 			}

value_collate.go

@@ -133,7 +133,8 @@ func gson2collate(obj interface{}, code []byte, config *Config) int {
 		poolobj := config.pools.keysPool.Get()
 		keys := poolobj.([]string)
 		defer config.pools.keysPool.Put(poolobj)
-		for _, key := range sortProps(value, keys) {
+
+		for _, key := range sortProps1(value, keys) {
 			n += collateString(key, code[n:], config)       // encode key
 			n += gson2collate(value[key], code[n:], config) // encode value
 		}

value_json.go

@@ -114,8 +114,12 @@ func value2json(value interface{}, out []byte, config *Config) int {
 		out[n] = '{'
 		n++
 
+		poolobj := config.pools.keysPool.Get()
+		keys := poolobj.([]string)
+		defer config.pools.keysPool.Put(poolobj)
+
 		count := len(v)
-		for key := range v {
+		for _, key := range sortProps1(v, keys) {
 			outsl, err = encodeString(str2bytes(key), out[n:n])
 			if err != nil {
 				panic("error encoding key")
@@ -141,8 +145,12 @@ func value2json(value interface{}, out []byte, config *Config) int {
 		out[n] = '{'
 		n++
 
+		poolobj := config.pools.keysPool.Get()
+		keys := poolobj.([]string)
+		defer config.pools.keysPool.Put(poolobj)
+
 		count := len(v)
-		for key := range v {
+		for _, key := range sortProps2(v, keys) {
 			outsl, err = encodeString(str2bytes(key), out[n:n])
 			if err != nil {
 				panic("error encoding key")