Minor refactoring

Author: calmh

interpreter.go

@@ -17,7 +17,7 @@ type Interpreter struct {
 	session    *Session
 }
 
-// IPFIX type of an Information Element ("Field").
+// FieldType is the IPFIX type of an Information Element ("Field").
 type FieldType int
 
 // The available field types as defined by RFC 5102.
@@ -45,6 +45,8 @@ const (
 	Ipv6Address
 )
 
+// FieldTypes maps string representations of field types into their
+// corresponding FieldType value.
 var FieldTypes = map[string]FieldType{
 	"unsigned8":            Uint8,
 	"unsigned16":           Uint16,
@@ -68,7 +70,8 @@ var FieldTypes = map[string]FieldType{
 	"ipv6Address":          Ipv6Address,
 }
 
-// DictionaryEntry provides a mapping between an (Enterprise, Field) pair and a Name and Type.
+// DictionaryEntry provides a mapping between an (Enterprise, Field) pair and
+// a Name and Type.
 type DictionaryEntry struct {
 	Name         string
 	FieldID      uint16

parser.go

@@ -128,7 +128,7 @@ func (s *Session) ParseReader(r io.Reader) (Message, error) {
 		return Message{}, err
 	}
 
-	sl := NewSlice(bs[msgHeaderLength:])
+	sl := newSlice(bs[msgHeaderLength:])
 	var msg Message
 	msg.Header = hdr
 	msg.TemplateRecords, msg.DataRecords, err = s.readBuffer(sl)
@@ -142,7 +142,7 @@ func (s *Session) ParseBuffer(bs []byte) (Message, error) {
 	var msg Message
 	var err error
 
-	sl := NewSlice(bs)
+	sl := newSlice(bs)
 	msg.Header.unmarshal(sl)
 	msg.TemplateRecords, msg.DataRecords, err = s.readBuffer(sl)
 	return msg, err
@@ -160,7 +160,7 @@ func (s *Session) readBuffer(sl *slice) ([]TemplateRecord, []DataRecord, error)
 
 		// Grab the bytes representing the set
 		setLen := int(setHdr.Length) - setHeaderLength
-		setSl := NewSlice(sl.Cut(setLen))
+		setSl := newSlice(sl.Cut(setLen))
 		if err := sl.Error(); err != nil {
 			return nil, nil, err
 		}
@@ -207,8 +207,7 @@ func (s *Session) readSet(setHdr setHeader, sl *slice) ([]TemplateRecord, []Data
 
 		case setHdr.SetID == 2:
 			// Template Set
-			var tr TemplateRecord
-			tr = s.readTemplateRecord(sl)
+			tr := s.readTemplateRecord(sl)
 			trecs = append(trecs, tr)
 
 			s.registerTemplateRecord(tr)
@@ -230,9 +229,7 @@ func (s *Session) readSet(setHdr setHeader, sl *slice) ([]TemplateRecord, []Data
 
 			if tpl != nil {
 				// Data set
-				var ds DataRecord
-				var err error
-				ds, err = s.readDataRecord(sl, tpl)
+				ds, err := s.readDataRecord(sl, tpl)
 				if err != nil {
 					return nil, nil, err
 				}
@@ -251,8 +248,8 @@ func (s *Session) readSet(setHdr setHeader, sl *slice) ([]TemplateRecord, []Data
 }
 
 func (s *Session) readDataRecord(sl *slice, tpl []TemplateFieldSpecifier) (DataRecord, error) {
-	var ds DataRecord
-	ds.Fields = make([][]byte, len(tpl))
+	var dr DataRecord
+	dr.Fields = make([][]byte, len(tpl))
 
 	var err error
 	total := 0
@@ -267,7 +264,7 @@ func (s *Session) readDataRecord(sl *slice, tpl []TemplateFieldSpecifier) (DataR
 			l := int(tpl[i].Length)
 			val = sl.Cut(l)
 		}
-		ds.Fields[i] = val
+		dr.Fields[i] = val
 		total += len(val)
 	}
 
@@ -278,13 +275,13 @@ func (s *Session) readDataRecord(sl *slice, tpl []TemplateFieldSpecifier) (DataR
 
 	cp := make([]byte, total)
 	next := 0
-	for i := range ds.Fields {
-		ln := copy(cp[next:], ds.Fields[i])
-		ds.Fields[i] = cp[next : next+ln]
+	for i := range dr.Fields {
+		ln := copy(cp[next:], dr.Fields[i])
+		dr.Fields[i] = cp[next : next+ln]
 		next += ln
 	}
 
-	return ds, sl.Error()
+	return dr, sl.Error()
 }
 
 func (s *Session) readTemplateRecord(sl *slice) TemplateRecord {
@@ -318,10 +315,6 @@ func (s *Session) readVariableLength(sl *slice) (val []byte, err error) {
 		l = int(sl.Uint16())
 	}
 
-	if l > sl.Len() {
-		return nil, io.EOF
-	}
-
 	return sl.Cut(l), sl.Error()
 }
 

read.go

@@ -17,7 +17,7 @@ func Read(r io.Reader, bs []byte) ([]byte, MessageHeader, error) {
 	}
 
 	var hdr MessageHeader
-	hdr.unmarshal(NewSlice(bs))
+	hdr.unmarshal(newSlice(bs))
 
 	if hdr.Version != 10 {
 		return nil, hdr, ErrVersion

slice.go

@@ -7,7 +7,7 @@ type slice struct {
 	err error
 }
 
-func NewSlice(bs []byte) *slice {
+func newSlice(bs []byte) *slice {
 	return &slice{
 		bs: bs,
 	}

slice_test.go

@@ -6,7 +6,7 @@ import (
 )
 
 func TestSliceCut(t *testing.T) {
-	s := NewSlice([]byte{1, 2, 3, 4, 5, 6, 7, 8})
+	s := newSlice([]byte{1, 2, 3, 4, 5, 6, 7, 8})
 	r := s.Cut(4)
 
 	if !bytes.Equal(r, []byte{1, 2, 3, 4}) {
@@ -19,7 +19,7 @@ func TestSliceCut(t *testing.T) {
 }
 
 func TestSliceUint16(t *testing.T) {
-	s := NewSlice([]byte{1, 2, 3, 4, 5})
+	s := newSlice([]byte{1, 2, 3, 4, 5})
 
 	if v := s.Uint16(); v != 1<<8+2 {
 		t.Errorf("%v != 1<<8+2", v)