add Packer and Unpacker to the field spec

moov-io · Jun 7, 2024 · 6734369 · 6734369
1 parent a234a4a
commit 6734369
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Showing 9 changed files with 133 additions and 171 deletions.
diff --git a/field/binary.go b/field/binary.go
@@ -10,9 +10,11 @@ import (
 	"github.com/moov-io/iso8583/utils"
 )
 
-var _ Field = (*Binary)(nil)
-var _ json.Marshaler = (*Binary)(nil)
-var _ json.Unmarshaler = (*Binary)(nil)
+var (
+	_ Field            = (*Binary)(nil)
+	_ json.Marshaler   = (*Binary)(nil)
+	_ json.Unmarshaler = (*Binary)(nil)
+)
 
 type Binary struct {
 	value []byte
@@ -72,43 +74,24 @@ func (f *Binary) SetValue(v []byte) {
 func (f *Binary) Pack() ([]byte, error) {
 	data := f.value
 
-	if f.spec.Pad != nil {
-		data = f.spec.Pad.Pad(data, f.spec.Length)
-	}
-
-	packed, err := f.spec.Enc.Encode(data)
-	if err != nil {
-		return nil, fmt.Errorf("failed to encode content: %w", err)
-	}
-
-	packedLength, err := f.spec.Pref.EncodeLength(f.spec.Length, len(data))
-	if err != nil {
-		return nil, fmt.Errorf("failed to encode length: %w", err)
-	}
+	packer := f.spec.getPacker()
 
-	return append(packedLength, packed...), nil
+	return packer.Pack(data, f.spec)
 }
 
 func (f *Binary) Unpack(data []byte) (int, error) {
-	dataLen, prefBytes, err := f.spec.Pref.DecodeLength(f.spec.Length, data)
-	if err != nil {
-		return 0, fmt.Errorf("failed to decode length: %w", err)
-	}
+	unpacker := f.spec.getUnpacker()
 
-	raw, read, err := f.spec.Enc.Decode(data[prefBytes:], dataLen)
+	raw, bytesRead, err := unpacker.Unpack(data, f.spec)
 	if err != nil {
-		return 0, fmt.Errorf("failed to decode content: %w", err)
-	}
-
-	if f.spec.Pad != nil {
-		raw = f.spec.Pad.Unpad(raw)
+		return 0, err
 	}
 
 	if err := f.SetBytes(raw); err != nil {
 		return 0, fmt.Errorf("failed to set bytes: %w", err)
 	}
 
-	return read + prefBytes, nil
+	return bytesRead, nil
 }
 
 // Deprecated. Use Marshal instead

diff --git a/field/composite.go b/field/composite.go
@@ -15,9 +15,11 @@ import (
 	"github.com/moov-io/iso8583/utils"
 )
 
-var _ Field = (*Composite)(nil)
-var _ json.Marshaler = (*Composite)(nil)
-var _ json.Unmarshaler = (*Composite)(nil)
+var (
+	_ Field            = (*Composite)(nil)
+	_ json.Marshaler   = (*Composite)(nil)
+	_ json.Unmarshaler = (*Composite)(nil)
+)
 
 // Composite is a wrapper object designed to hold ISO8583 TLVs, subfields and
 // subelements. Because Composite handles both of these usecases generically,

diff --git a/field/numeric.go b/field/numeric.go
@@ -9,9 +9,11 @@ import (
 	"github.com/moov-io/iso8583/utils"
 )
 
-var _ Field = (*Numeric)(nil)
-var _ json.Marshaler = (*Numeric)(nil)
-var _ json.Unmarshaler = (*Numeric)(nil)
+var (
+	_ Field            = (*Numeric)(nil)
+	_ json.Marshaler   = (*Numeric)(nil)
+	_ json.Unmarshaler = (*Numeric)(nil)
+)
 
 type Numeric struct {
 	value int64
@@ -84,44 +86,25 @@ func (f *Numeric) SetValue(v int64) {
 func (f *Numeric) Pack() ([]byte, error) {
 	data := []byte(strconv.FormatInt(f.value, 10))
 
-	if f.spec.Pad != nil {
-		data = f.spec.Pad.Pad(data, f.spec.Length)
-	}
-
-	packed, err := f.spec.Enc.Encode(data)
-	if err != nil {
-		return nil, fmt.Errorf("failed to encode content: %w", err)
-	}
-
-	packedLength, err := f.spec.Pref.EncodeLength(f.spec.Length, len(data))
-	if err != nil {
-		return nil, fmt.Errorf("failed to encode length: %w", err)
-	}
+	packer := f.spec.getPacker()
 
-	return append(packedLength, packed...), nil
+	return packer.Pack(data, f.spec)
 }
 
 // returns number of bytes was read
 func (f *Numeric) Unpack(data []byte) (int, error) {
-	dataLen, prefBytes, err := f.spec.Pref.DecodeLength(f.spec.Length, data)
-	if err != nil {
-		return 0, fmt.Errorf("failed to decode length: %w", err)
-	}
+	unpacker := f.spec.getUnpacker()
 
-	raw, read, err := f.spec.Enc.Decode(data[prefBytes:], dataLen)
+	raw, bytesRead, err := unpacker.Unpack(data, f.spec)
 	if err != nil {
-		return 0, fmt.Errorf("failed to decode content: %w", err)
-	}
-
-	if f.spec.Pad != nil {
-		raw = f.spec.Pad.Unpad(raw)
+		return 0, err
 	}
 
 	if err := f.SetBytes(raw); err != nil {
 		return 0, fmt.Errorf("failed to set bytes: %w", err)
 	}
 
-	return read + prefBytes, nil
+	return bytesRead, nil
 }
 
 // Deprecated. Use Marshal instead

diff --git a/field/packer_unpacker.go b/field/packer_unpacker.go
@@ -0,0 +1,43 @@
+package field
+
+import "fmt"
+
+type DefaultPacker struct{}
+
+func (p DefaultPacker) Pack(data []byte, spec *Spec) ([]byte, error) {
+	if spec.Pad != nil {
+		data = spec.Pad.Pad(data, spec.Length)
+	}
+
+	packed, err := spec.Enc.Encode(data)
+	if err != nil {
+		return nil, fmt.Errorf("failed to encode content: %w", err)
+	}
+
+	packedLength, err := spec.Pref.EncodeLength(spec.Length, len(data))
+	if err != nil {
+		return nil, fmt.Errorf("failed to encode length: %w", err)
+	}
+
+	return append(packedLength, packed...), nil
+}
+
+type DefaultUnpacker struct{}
+
+func (u DefaultUnpacker) Unpack(data []byte, spec *Spec) ([]byte, int, error) {
+	dataLen, prefBytes, err := spec.Pref.DecodeLength(spec.Length, data)
+	if err != nil {
+		return nil, 0, fmt.Errorf("failed to decode length: %w", err)
+	}
+
+	raw, read, err := spec.Enc.Decode(data[prefBytes:], dataLen)
+	if err != nil {
+		return nil, 0, fmt.Errorf("failed to decode content: %w", err)
+	}
+
+	if spec.Pad != nil {
+		raw = spec.Pad.Unpad(raw)
+	}
+
+	return raw, read + prefBytes, nil
+}
diff --git a/field/spec.go b/field/spec.go
@@ -80,6 +80,22 @@ type Spec struct {
 	// Bitmap defines a bitmap field that is used only by a composite field type.
 	// It defines the way that the composite will determine its subflieds existence.
 	Bitmap *Bitmap
+	// Packer is the packer used to pack the field. Default is DefaultPacker.
+	Packer Packer
+	// Unpacker is the unpacker used to unpack the field. Default is DefaultUnpacker.
+	Unpacker Unpacker
+}
+
+// Packer is the interface that wraps the Pack method.
+type Packer interface {
+	Pack(data []byte, spec *Spec) ([]byte, error)
+}
+
+// Unpacker is the interface that wraps the Unpack method.
+type Unpacker interface {
+	// Unpack unpacks the data according to the spec and returns the
+	// unpacked data and the number of bytes read.
+	Unpack(data []byte, spec *Spec) ([]byte, int, error)
 }
 
 func NewSpec(length int, desc string, enc encoding.Encoder, pref prefix.Prefixer) *Spec {
@@ -91,6 +107,20 @@ func NewSpec(length int, desc string, enc encoding.Encoder, pref prefix.Prefixer
 	}
 }
 
+func (spec *Spec) getPacker() Packer {
+	if spec.Packer == nil {
+		return DefaultPacker{}
+	}
+	return spec.Packer
+}
+
+func (spec *Spec) getUnpacker() Unpacker {
+	if spec.Unpacker == nil {
+		return DefaultUnpacker{}
+	}
+	return spec.Unpacker
+}
+
 // Validate validates the spec.
 func (s *Spec) Validate() error {
 	if s.Enc != nil {

diff --git a/field/string.go b/field/string.go
@@ -10,9 +10,11 @@ import (
 	"github.com/moov-io/iso8583/utils"
 )
 
-var _ Field = (*String)(nil)
-var _ json.Marshaler = (*String)(nil)
-var _ json.Unmarshaler = (*String)(nil)
+var (
+	_ Field            = (*String)(nil)
+	_ json.Marshaler   = (*String)(nil)
+	_ json.Unmarshaler = (*String)(nil)
+)
 
 type String struct {
 	value string
@@ -72,43 +74,24 @@ func (f *String) SetValue(v string) {
 func (f *String) Pack() ([]byte, error) {
 	data := []byte(f.value)
 
-	if f.spec.Pad != nil {
-		data = f.spec.Pad.Pad(data, f.spec.Length)
-	}
-
-	packed, err := f.spec.Enc.Encode(data)
-	if err != nil {
-		return nil, fmt.Errorf("failed to encode content: %w", err)
-	}
-
-	packedLength, err := f.spec.Pref.EncodeLength(f.spec.Length, len(data))
-	if err != nil {
-		return nil, fmt.Errorf("failed to encode length: %w", err)
-	}
+	packer := f.spec.getPacker()
 
-	return append(packedLength, packed...), nil
+	return packer.Pack(data, f.spec)
 }
 
 func (f *String) Unpack(data []byte) (int, error) {
-	dataLen, prefBytes, err := f.spec.Pref.DecodeLength(f.spec.Length, data)
-	if err != nil {
-		return 0, fmt.Errorf("failed to decode length: %w", err)
-	}
+	unpacker := f.spec.getUnpacker()
 
-	raw, read, err := f.spec.Enc.Decode(data[prefBytes:], dataLen)
+	raw, bytesRead, err := unpacker.Unpack(data, f.spec)
 	if err != nil {
-		return 0, fmt.Errorf("failed to decode content: %w", err)
-	}
-
-	if f.spec.Pad != nil {
-		raw = f.spec.Pad.Unpad(raw)
+		return 0, err
 	}
 
 	if err := f.SetBytes(raw); err != nil {
 		return 0, fmt.Errorf("failed to set bytes: %w", err)
 	}
 
-	return read + prefBytes, nil
+	return bytesRead, nil
 }
 
 // Deprecated. Use Marshal instead

diff --git a/field/track1.go b/field/track1.go
@@ -28,9 +28,7 @@ const (
 	track1Format     = `%s%s^%s^%s%s%s`
 )
 
-var (
-	track1Regex = regexp.MustCompile(`^([A-Z]{1})([0-9]{1,19})\^([^\^]{2,26})\^([0-9]{4}|\^)([0-9]{3}|\^)([^\?]+)$`)
-)
+var track1Regex = regexp.MustCompile(`^([A-Z]{1})([0-9]{1,19})\^([^\^]{2,26})\^([0-9]{4}|\^)([0-9]{3}|\^)([^\?]+)$`)
 
 func NewTrack1(spec *Spec) *Track1 {
 	return &Track1{
@@ -68,37 +66,18 @@ func (f *Track1) Pack() ([]byte, error) {
 		return nil, err
 	}
 
-	if f.spec.Pad != nil {
-		data = f.spec.Pad.Pad(data, f.spec.Length)
-	}
-
-	packed, err := f.spec.Enc.Encode(data)
-	if err != nil {
-		return nil, fmt.Errorf("failed to encode content: %w", err)
-	}
-
-	packedLength, err := f.spec.Pref.EncodeLength(f.spec.Length, len(data))
-	if err != nil {
-		return nil, fmt.Errorf("failed to encode length: %w", err)
-	}
+	packer := f.spec.getPacker()
 
-	return append(packedLength, packed...), nil
+	return packer.Pack(data, f.spec)
 }
 
 // returns number of bytes was read
 func (f *Track1) Unpack(data []byte) (int, error) {
-	dataLen, prefBytes, err := f.spec.Pref.DecodeLength(f.spec.Length, data)
-	if err != nil {
-		return 0, fmt.Errorf("failed to decode length: %w", err)
-	}
+	unpacker := f.spec.getUnpacker()
 
-	raw, read, err := f.spec.Enc.Decode(data[prefBytes:], dataLen)
+	raw, bytesRead, err := unpacker.Unpack(data, f.spec)
 	if err != nil {
-		return 0, fmt.Errorf("failed to decode content: %w", err)
-	}
-
-	if f.spec.Pad != nil {
-		raw = f.spec.Pad.Unpad(raw)
+		return 0, err
 	}
 
 	if len(raw) > 0 {
@@ -108,7 +87,7 @@ func (f *Track1) Unpack(data []byte) (int, error) {
 		}
 	}
 
-	return read + prefBytes, nil
+	return bytesRead, nil
 }
 
 // Deprecated. Use Marshal instead