Marshal map[string]string

encode.go

@@ -0,0 +1,69 @@
+package ltsv
+
+import (
+	"fmt"
+	"reflect"
+	"strings"
+)
+
+type Marshaler interface {
+	MarshalLTSV([]byte) error
+}
+
+// MarshalError is an error type for Marshal()
+type MarshalError map[string]error
+
+func (m MarshalError) Error() string {
+	if len(m) == 0 {
+		return "(no error)"
+	}
+
+	ee := make([]string, 0, len(m))
+	for name, err := range m {
+		ee = append(ee, fmt.Sprintf("field %q: %s", name, err))
+	}
+
+	return strings.Join(ee, "\n")
+}
+
+// OfField returns the error correspoinding to a given field
+func (m MarshalError) OfField(name string) error {
+	return m[name]
+}
+
+// An MarshalTypeError describes a LTSV value that was
+// not appropriate for a value of a specific Go type.
+type MarshalTypeError struct {
+	Value string
+	Type  reflect.Type
+}
+
+func (e *MarshalTypeError) Error() string {
+	return "ltsv: cannot marshal " + e.Value + " into Go value of type " + e.Type.String()
+}
+
+func Marshal(v interface{}) ([]byte, error) {
+	rv := reflect.ValueOf(v)
+	if rv.Kind() == reflect.Ptr {
+		rv = rv.Elem()
+	}
+	if rv.Kind() != reflect.Struct && rv.Kind() != reflect.Map {
+		return nil, fmt.Errorf("not a struct/map: %v", v)
+	}
+
+	if rv.Kind() == reflect.Map {
+		kt := rv.Type().Key()
+		vt := rv.Type().Elem()
+		if kt.Kind() != reflect.String || vt.Kind() != reflect.String {
+			return nil, fmt.Errorf("not a map[string]string")
+		}
+
+		mKeys := rv.MapKeys()
+		arr := make([]string, len(mKeys), len(mKeys))
+		for i, k := range mKeys {
+			arr[i] = k.String() + ":" + rv.MapIndex(k).String()
+		}
+		return []byte(strings.Join(arr, "\t")), nil
+	}
+	return nil, nil
+}

encode_test.go

@@ -0,0 +1,16 @@
+package ltsv
+
+import "testing"
+
+func TestMarshal(t *testing.T) {
+	data := map[string]string{
+		"hoge": "fuga",
+		"piyo": "piyo",
+	}
+	expect1 := []byte("hoge:fuga\tpiyo:piyo")
+	expect2 := []byte("piyo:piyo\thoge:fuga")
+	r, _ := Marshal(data)
+	if string(r) != string(expect1) && string(r) != string(expect2) {
+		t.Errorf("result is not expected: %s", string(r))
+	}
+}