Added error type.

Error handling with sub types

allocator.go

@@ -1,13 +1,13 @@
 package ssob
 
 import (
-	"errors"
+	"fmt"
 	"reflect"
 )
 
 func allocType(out reflect.Value) (err error) {
 	if out.Type().Kind() != reflect.Ptr || out.IsNil() {
-		return errors.New("ssob: Error allocating type (Got nil pointer)")
+		return fmt.Errorf("ssob: Error allocating type (Got nil pointer): %w", ErrValueInvalid)
 	}
 
 	t := out.Elem().Type()

decoder.go

@@ -3,6 +3,7 @@ package ssob
 import (
 	"encoding/binary"
 	"errors"
+	"fmt"
 	"io"
 	"reflect"
 	"sync"
@@ -24,12 +25,23 @@ func (dec *Decoder) Decode(e interface{}) (err error) {
 }
 
 func (dec *Decoder) DecodeValue(value reflect.Value) (err error) {
+	if value.Type() == reflect.TypeOf(errors.New("")) || value.Type() == reflect.TypeOf((*error)(nil)) {
+		var errstr string
+		if err = dec.Decode(&errstr); err != nil {
+			return err
+		}
+		if errstr != "" {
+			*value.Interface().(*error) = errors.New(errstr)
+		}
+		return nil
+	}
+
 	if value.Kind() == reflect.Invalid {
-		return errors.New("ssob: Cannot decode nil value")
+		return fmt.Errorf("ssob: Cannot decode nil: %w", ErrValueInvalid)
 	}
 
 	if value.Kind() == reflect.Ptr && value.IsNil() {
-		return errors.New("ssob: Cannot decode nil of type " + value.Type().String())
+		return fmt.Errorf("ssob: Cannot decode nil of type %s: %w", value.Type().String(), ErrValueInvalid)
 	}
 
 	dec.mutex.Lock()

encoder.go

@@ -3,6 +3,7 @@ package ssob
 import (
 	"encoding/binary"
 	"errors"
+	"fmt"
 	"io"
 	"reflect"
 	"sync"
@@ -24,12 +25,20 @@ func (enc *Encoder) Encode(e interface{}) (err error) {
 }
 
 func (enc *Encoder) EncodeValue(value reflect.Value) (err error) {
+	if value.Type() == reflect.TypeOf(errors.New("")) || value.Type() == reflect.TypeOf((*error)(nil)).Elem() {
+		if value.IsNil() {
+			return enc.Encode(string(""))
+		} else {
+			return enc.Encode(value.Interface().(error).Error())
+		}
+	}
+
 	if value.Kind() == reflect.Invalid {
-		return errors.New("ssob: Cannot encode nil value")
+		return fmt.Errorf("ssob: Cannot encode nil: %w", ErrValueInvalid)
 	}
 
 	if value.Kind() == reflect.Ptr && value.IsNil() {
-		return errors.New("ssob: Cannot encode nil of type " + value.Type().String())
+		return fmt.Errorf("ssob: Cannot encode nil of type %s: %w", value.Type().String(), ErrValueInvalid)
 	}
 
 	bb, err := marshal(value.Interface())

error.go

@@ -0,0 +1,9 @@
+package ssob
+
+import "errors"
+
+var ErrValueInvalid = errors.New("value invalid")
+var ErrTypeInvalid = errors.New("type invalid")
+var ErrTypeUnknown = errors.New("type unknown")
+var ErrTypeMismatch = errors.New("type mismatch")
+var ErrParseFailed = errors.New("parsing failed")

marshal.go

@@ -2,7 +2,7 @@ package ssob
 
 import (
 	"encoding/binary"
-	"errors"
+	"fmt"
 	"math"
 	"reflect"
 )
@@ -98,85 +98,85 @@ func init() {
 		if i, ok := e.(bool); ok {
 			return MarshalBool(i), nil
 		}
-		return nil, errors.New("ssob: Incompatible type - expected bool")
+		return nil, fmt.Errorf("ssob: Incompatible type - expected bool: %w", ErrTypeMismatch)
 	})
 	RegisterEncoder("int8", func(e interface{}) (ret []byte, err error) {
 		if i, ok := e.(int8); ok {
 			return MarshalInt8(i), nil
 		}
-		return nil, errors.New("ssob: Incompatible type - expected int8")
+		return nil, fmt.Errorf("ssob: Incompatible type - expected int8: %w", ErrTypeMismatch)
 	})
 	RegisterEncoder("uint8", func(e interface{}) (ret []byte, err error) {
 		if i, ok := e.(uint8); ok {
 			return MarshalUint8(i), nil
 		}
-		return nil, errors.New("ssob: Incompatible type - expected uint8")
+		return nil, fmt.Errorf("ssob: Incompatible type - expected uint8: %w", ErrTypeMismatch)
 	})
 	RegisterEncoder("int16", func(e interface{}) (ret []byte, err error) {
 		if i, ok := e.(int16); ok {
 			return MarshalInt16(i), nil
 		}
-		return nil, errors.New("ssob: Incompatible type - expected int16")
+		return nil, fmt.Errorf("ssob: Incompatible type - expected int16: %w", ErrTypeMismatch)
 	})
 	RegisterEncoder("uint16", func(e interface{}) (ret []byte, err error) {
 		if i, ok := e.(uint16); ok {
 			return MarshalUint16(i), nil
 		}
-		return nil, errors.New("ssob: Incompatible type - expected uint16")
+		return nil, fmt.Errorf("ssob: Incompatible type - expected uint16: %w", ErrTypeMismatch)
 	})
 	RegisterEncoder("int32", func(e interface{}) (ret []byte, err error) {
 		if i, ok := e.(int32); ok {
 			return MarshalInt32(i), nil
 		}
-		return nil, errors.New("ssob: Incompatible type - expected int32")
+		return nil, fmt.Errorf("ssob: Incompatible type - expected int32: %w", ErrTypeMismatch)
 	})
 	RegisterEncoder("uint32", func(e interface{}) (ret []byte, err error) {
 		if i, ok := e.(uint32); ok {
 			return MarshalUint32(i), nil
 		}
-		return nil, errors.New("ssob: Incompatible type - expected uint32")
+		return nil, fmt.Errorf("ssob: Incompatible type - expected uint32: %w", ErrTypeMismatch)
 	})
 	RegisterEncoder("float32", func(e interface{}) (ret []byte, err error) {
 		if i, ok := e.(float32); ok {
 			return MarshalFloat32(i), nil
 		}
-		return nil, errors.New("ssob: Incompatible type - expected float32")
+		return nil, fmt.Errorf("ssob: Incompatible type - expected float32: %w", ErrTypeMismatch)
 	})
 	RegisterEncoder("int64", func(e interface{}) (ret []byte, err error) {
 		if i, ok := e.(int64); ok {
 			return MarshalInt64(i), nil
 		}
-		return nil, errors.New("ssob: Incompatible type - expected int64")
+		return nil, fmt.Errorf("ssob: Incompatible type - expected int64: %w", ErrTypeMismatch)
 	})
 	RegisterEncoder("uint64", func(e interface{}) (ret []byte, err error) {
 		if i, ok := e.(uint64); ok {
 			return MarshalUint64(i), nil
 		}
-		return nil, errors.New("ssob: Incompatible type - expected uint64")
+		return nil, fmt.Errorf("ssob: Incompatible type - expected uint64: %w", ErrTypeMismatch)
 	})
 	RegisterEncoder("float64", func(e interface{}) (ret []byte, err error) {
 		if i, ok := e.(float64); ok {
 			return MarshalFloat64(i), nil
 		}
-		return nil, errors.New("ssob: Incompatible type - expected float64")
+		return nil, fmt.Errorf("ssob: Incompatible type - expected float64: %w", ErrTypeMismatch)
 	})
 	RegisterEncoder("string", func(e interface{}) (ret []byte, err error) {
 		if i, ok := e.(string); ok {
 			return MarshalString(i), nil
 		}
-		return nil, errors.New("ssob: Incompatible type - expected string")
+		return nil, fmt.Errorf("ssob: Incompatible type - expected string: %w", ErrTypeMismatch)
 	})
 }
 
 func encRegister(e interface{}) (err error) {
 	t := reflect.TypeOf(e)
 	if t == nil {
-		return errors.New("ssob: Invalid type")
+		return fmt.Errorf("ssob: nil type: %w", ErrTypeInvalid)
 	}
 
 	switch t.Kind() {
 	case reflect.Invalid:
-		return errors.New("ssob: Invalid type")
+		return fmt.Errorf("ssob: invalid type: %w", ErrTypeInvalid)
 	case reflect.Array:
 		f := func(e interface{}) (ret []byte, err error) {
 			v := reflect.ValueOf(e)
@@ -257,7 +257,7 @@ func encRegister(e interface{}) (err error) {
 			}
 		}
 		if len(mfields) == 0 {
-			return errors.New("ssob: No exported fields for " + string(t.Name()))
+			return fmt.Errorf("ssob: No exported fields for %s: %w", string(t.Name()), ErrParseFailed)
 		}
 
 		f := func(e interface{}) (ret []byte, err error) {
@@ -340,7 +340,7 @@ func encRegister(e interface{}) (err error) {
 		}
 		encoderCache[t.Name()] = f
 	default:
-		return errors.New("ssob: Unknown type " + string(t.Name()))
+		return fmt.Errorf("ssob: %s: %w", string(t.Name()), ErrTypeUnknown)
 	}
 
 	return nil
@@ -373,7 +373,7 @@ func marshalBaseType(e interface{}) (ret []byte, err error) {
 	case string:
 		return encoderCache["string"](t)
 	default:
-		return nil, errors.New("ssob: No base type")
+		return nil, fmt.Errorf("ssob: No base type: %w", ErrTypeUnknown)
 	}
 }
 
@@ -389,7 +389,7 @@ func marshal(e interface{}) (ret []byte, err error) {
 	switch t.Kind() {
 	case reflect.Ptr:
 		if v.IsNil() {
-			return nil, errors.New("ssob: Cannot marshal nil pointer")
+			return nil, fmt.Errorf("ssob: Cannot marshal nil pointer: %w", ErrValueInvalid)
 		}
 		p := reflect.Indirect(v)
 		return marshal(p.Interface())

unmarshal.go

@@ -2,26 +2,26 @@ package ssob
 
 import (
 	"encoding/binary"
-	"errors"
+	"fmt"
 	"math"
 	"reflect"
 )
 
 func UnmarshalString(in []byte) (ret string, n int, err error) {
 	if len(in) < 4 {
-		return "", 0, errors.New("ssob: Invalid input to decode string")
+		return "", 0, fmt.Errorf("ssob: Decoding string: %w", ErrTypeInvalid)
 	}
 	l := int32(binary.BigEndian.Uint32(in))
 
 	if len(in[4:]) < int(l) {
-		return "", 0, errors.New("ssob: Invalid length of string")
+		return "", 0, fmt.Errorf("ssob: Invalid length of string: %w", ErrValueInvalid)
 	}
 	return string(in[4 : l+4]), int(l) + 4, nil
 }
 
 func UnmarshalBool(in []byte) (ret bool, n int, err error) {
 	if len(in) < 1 {
-		return false, 0, errors.New("ssob: Invalid input to decode bool")
+		return false, 0, fmt.Errorf("ssob: Decoding bool: %w", ErrTypeInvalid)
 	}
 
 	if in[0] == byte(0) {
@@ -32,7 +32,7 @@ func UnmarshalBool(in []byte) (ret bool, n int, err error) {
 
 func UnmarshalInt8(in []byte) (ret int8, n int, err error) {
 	if len(in) < 1 {
-		return 0, 0, errors.New("ssob: Invalid input to decode int8")
+		return 0, 0, fmt.Errorf("ssob: Decoding int8: %w", ErrTypeInvalid)
 	}
 
 	return int8(in[0]), 1, nil
@@ -40,7 +40,7 @@ func UnmarshalInt8(in []byte) (ret int8, n int, err error) {
 
 func UnmarshalUint8(in []byte) (ret uint8, n int, err error) {
 	if len(in) < 1 {
-		return 0, 0, errors.New("ssob: Invalid input to decode uint8")
+		return 0, 0, fmt.Errorf("ssob: Decoding uint8: %w", ErrTypeInvalid)
 	}
 
 	return uint8(in[0]), 1, nil
@@ -48,7 +48,7 @@ func UnmarshalUint8(in []byte) (ret uint8, n int, err error) {
 
 func UnmarshalInt16(in []byte) (ret int16, n int, err error) {
 	if len(in) < 2 {
-		return 0, 0, errors.New("ssob: Invalid input to decode int16")
+		return 0, 0, fmt.Errorf("ssob: Decoding int16: %w", ErrTypeInvalid)
 	}
 
 	return int16(binary.BigEndian.Uint16(in[0:2])), 2, nil
@@ -56,7 +56,7 @@ func UnmarshalInt16(in []byte) (ret int16, n int, err error) {
 
 func UnmarshalUint16(in []byte) (ret uint16, n int, err error) {
 	if len(in) < 2 {
-		return 0, 0, errors.New("ssob: Invalid input to decode uint16")
+		return 0, 0, fmt.Errorf("ssob: Decoding uint16: %w", ErrTypeInvalid)
 	}
 
 	return binary.BigEndian.Uint16(in[0:2]), 2, nil
@@ -64,7 +64,7 @@ func UnmarshalUint16(in []byte) (ret uint16, n int, err error) {
 
 func UnmarshalInt32(in []byte) (ret int32, n int, err error) {
 	if len(in) < 4 {
-		return 0, 0, errors.New("ssob: Invalid input to decode int32")
+		return 0, 0, fmt.Errorf("ssob: Decoding int32: %w", ErrTypeInvalid)
 	}
 
 	return int32(binary.BigEndian.Uint32(in[0:4])), 4, nil
@@ -72,7 +72,7 @@ func UnmarshalInt32(in []byte) (ret int32, n int, err error) {
 
 func UnmarshalUint32(in []byte) (ret uint32, n int, err error) {
 	if len(in) < 4 {
-		return 0, 0, errors.New("ssob: Invalid input to decode uint32")
+		return 0, 0, fmt.Errorf("ssob: Decoding uint32: %w", ErrTypeInvalid)
 	}
 
 	return binary.BigEndian.Uint32(in[0:4]), 4, nil
@@ -80,7 +80,7 @@ func UnmarshalUint32(in []byte) (ret uint32, n int, err error) {
 
 func UnmarshalFloat32(in []byte) (ret float32, n int, err error) {
 	if len(in) < 4 {
-		return 0, 0, errors.New("ssob: Invalid input to decode float32")
+		return 0, 0, fmt.Errorf("ssob: Decoding float32: %w", ErrTypeInvalid)
 	}
 
 	return float32(math.Float32frombits(binary.BigEndian.Uint32(in[0:4]))), 4, nil
@@ -88,7 +88,7 @@ func UnmarshalFloat32(in []byte) (ret float32, n int, err error) {
 
 func UnmarshalInt64(in []byte) (ret int64, n int, err error) {
 	if len(in) < 8 {
-		return 0, 0, errors.New("ssob: Invalid input to decode int64")
+		return 0, 0, fmt.Errorf("ssob: Decoding int64: %w", ErrTypeInvalid)
 	}
 
 	return int64(binary.BigEndian.Uint64(in[0:8])), 8, nil
@@ -96,7 +96,7 @@ func UnmarshalInt64(in []byte) (ret int64, n int, err error) {
 
 func UnmarshalUint64(in []byte) (ret uint64, n int, err error) {
 	if len(in) < 8 {
-		return 0, 0, errors.New("ssob: Invalid input to decode uint64")
+		return 0, 0, fmt.Errorf("ssob: Decoding uint64: %w", ErrTypeInvalid)
 	}
 
 	return binary.BigEndian.Uint64(in[0:8]), 8, nil
@@ -104,7 +104,7 @@ func UnmarshalUint64(in []byte) (ret uint64, n int, err error) {
 
 func UnmarshalFloat64(in []byte) (ret float64, n int, err error) {
 	if len(in) < 8 {
-		return 0, 0, errors.New("ssob: Invalid input to decode float64")
+		return 0, 0, fmt.Errorf("ssob: Decoding float64: %w", ErrTypeInvalid)
 	}
 
 	return float64(math.Float64frombits(binary.BigEndian.Uint64(in[0:8]))), 8, nil
@@ -121,96 +121,96 @@ func init() {
 			*i, n, err = UnmarshalBool(in)
 			return n, err
 		}
-		return 0, errors.New("ssob: Incompatible type - expected bool")
+		return 0, fmt.Errorf("ssob: Incompatible type - expected bool: %w", ErrTypeMismatch)
 	})
 	RegisterDecoder("int8", func(e interface{}, in []byte) (n int, err error) {
 		if i, ok := e.(*int8); ok {
 			*i, n, err = UnmarshalInt8(in)
 			return n, err
 		}
-		return 0, errors.New("ssob: Incompatible type - expected int8")
+		return 0, fmt.Errorf("ssob: Incompatible type - expected int8: %w", ErrTypeMismatch)
 	})
 	RegisterDecoder("uint8", func(e interface{}, in []byte) (n int, err error) {
 		if i, ok := e.(*uint8); ok {
 			*i, n, err = UnmarshalUint8(in)
 			return n, err
 		}
-		return 0, errors.New("ssob: Incompatible type - expected uint8")
+		return 0, fmt.Errorf("ssob: Incompatible type - expected uint8: %w", ErrTypeMismatch)
 	})
 	RegisterDecoder("int16", func(e interface{}, in []byte) (n int, err error) {
 		if i, ok := e.(*int16); ok {
 			*i, n, err = UnmarshalInt16(in)
 			return n, err
 		}
-		return 0, errors.New("ssob: Incompatible type - expected int16")
+		return 0, fmt.Errorf("ssob: Incompatible type - expected int16: %w", ErrTypeMismatch)
 	})
 	RegisterDecoder("uint16", func(e interface{}, in []byte) (n int, err error) {
 		if i, ok := e.(*uint16); ok {
 			*i, n, err = UnmarshalUint16(in)
 			return n, err
 		}
-		return 0, errors.New("ssob: Incompatible type - expected uint16")
+		return 0, fmt.Errorf("ssob: Incompatible type - expected uint16: %w", ErrTypeMismatch)
 	})
 	RegisterDecoder("int32", func(e interface{}, in []byte) (n int, err error) {
 		if i, ok := e.(*int32); ok {
 			*i, n, err = UnmarshalInt32(in)
 			return n, err
 		}
-		return 0, errors.New("ssob: Incompatible type - expected int32")
+		return 0, fmt.Errorf("ssob: Incompatible type - expected int32: %w", ErrTypeMismatch)
 	})
 	RegisterDecoder("uint32", func(e interface{}, in []byte) (n int, err error) {
 		if i, ok := e.(*uint32); ok {
 			*i, n, err = UnmarshalUint32(in)
 			return n, err
 		}
-		return 0, errors.New("ssob: Incompatible type - expected uint32")
+		return 0, fmt.Errorf("ssob: Incompatible type - expected uint32: %w", ErrTypeMismatch)
 	})
 	RegisterDecoder("float32", func(e interface{}, in []byte) (n int, err error) {
 		if i, ok := e.(*float32); ok {
 			*i, n, err = UnmarshalFloat32(in)
 			return n, err
 		}
-		return 0, errors.New("ssob: Incompatible type - expected float32")
+		return 0, fmt.Errorf("ssob: Incompatible type - expected float32: %w", ErrTypeMismatch)
 	})
 	RegisterDecoder("int64", func(e interface{}, in []byte) (n int, err error) {
 		if i, ok := e.(*int64); ok {
 			*i, n, err = UnmarshalInt64(in)
 			return n, err
 		}
-		return 0, errors.New("ssob: Incompatible type - expected int64")
+		return 0, fmt.Errorf("ssob: Incompatible type - expected int64: %w", ErrTypeMismatch)
 	})
 	RegisterDecoder("uint64", func(e interface{}, in []byte) (n int, err error) {
 		if i, ok := e.(*uint64); ok {
 			*i, n, err = UnmarshalUint64(in)
 			return n, err
 		}
-		return 0, errors.New("ssob: Incompatible type - expected uint64")
+		return 0, fmt.Errorf("ssob: Incompatible type - expected uint64: %w", ErrTypeMismatch)
 	})
 	RegisterDecoder("float64", func(e interface{}, in []byte) (n int, err error) {
 		if i, ok := e.(*float64); ok {
 			*i, n, err = UnmarshalFloat64(in)
 			return n, err
 		}
-		return 0, errors.New("ssob: Incompatible type - expected float64")
+		return 0, fmt.Errorf("ssob: Incompatible type - expected float64: %w", ErrTypeMismatch)
 	})
 	RegisterDecoder("string", func(e interface{}, in []byte) (n int, err error) {
 		if i, ok := e.(*string); ok {
 			*i, n, err = UnmarshalString(in)
 			return n, err
 		}
-		return 0, errors.New("ssob: Incompatible type - expected string")
+		return 0, fmt.Errorf("ssob: Incompatible type - expected string: %w", ErrTypeMismatch)
 	})
 }
 
 func decRegister(e interface{}) (err error) {
 	t := reflect.TypeOf(e)
 	if t == nil {
-		return errors.New("ssob: Invalid type")
+		return fmt.Errorf("ssob: nil type: %w", ErrTypeInvalid)
 	}
 
 	switch t.Kind() {
 	case reflect.Invalid:
-		return errors.New("ssob: Invalid type")
+		return fmt.Errorf("ssob: invalid type: %w", ErrTypeInvalid)
 	case reflect.Array:
 		f := func(e interface{}, in []byte) (n int, err error) {
 			t := reflect.TypeOf(e)
@@ -218,7 +218,7 @@ func decRegister(e interface{}) (err error) {
 			pos := 0
 
 			if t.Kind() != reflect.Ptr || v.IsNil() {
-				return 0, errors.New("ssob: Cannot unmarshal to nil pointer")
+				return 0, fmt.Errorf("ssob: Cannot unmarshal to nil pointer: %w", ErrValueInvalid)
 			}
 
 			l, r, err := UnmarshalInt32(in)
@@ -229,7 +229,7 @@ func decRegister(e interface{}) (err error) {
 
 			ti := v.Elem()
 			if int(l) != ti.Len() {
-				return pos, errors.New("ssob: Invalid array length. Expected " + string(l) + " got " + string(ti.Len()))
+				return pos, fmt.Errorf("ssob: Invalid array length. Expected %s got %s: %w", string(l), string(ti.Len()), ErrValueInvalid)
 			}
 			for i := 0; i < int(l); i++ {
 				e := reflect.New(reflect.TypeOf(ti.Interface()).Elem())
@@ -250,7 +250,7 @@ func decRegister(e interface{}) (err error) {
 			pos := 0
 
 			if t.Kind() != reflect.Ptr || v.IsNil() {
-				return 0, errors.New("ssob: Cannot unmarshal to nil pointer")
+				return 0, fmt.Errorf("ssob: Cannot unmarshal to nil pointer: %w", ErrValueInvalid)
 			}
 
 			l, r, err := UnmarshalInt32(in)
@@ -283,7 +283,7 @@ func decRegister(e interface{}) (err error) {
 			}
 		}
 		if len(mfields) == 0 {
-			return errors.New("ssob: No exported fields for " + string(t.Name()))
+			return fmt.Errorf("ssob: No exported fields for %s: %w", string(t.Name()), ErrParseFailed)
 		}
 
 		f := func(e interface{}, in []byte) (n int, err error) {
@@ -292,7 +292,7 @@ func decRegister(e interface{}) (err error) {
 			pos := 0
 
 			if t.Kind() != reflect.Ptr || v.IsNil() {
-				return 0, errors.New("ssob: Cannot unmarshal to nil pointer")
+				return 0, fmt.Errorf("ssob: Cannot unmarshal to nil pointer: %w", ErrValueInvalid)
 			}
 
 			vi := reflect.Indirect(v)
@@ -314,7 +314,7 @@ func decRegister(e interface{}) (err error) {
 			pos := 0
 
 			if t.Kind() != reflect.Ptr || v.IsNil() {
-				return 0, errors.New("ssob: Cannot unmarshal to nil pointer")
+				return 0, fmt.Errorf("ssob: Cannot unmarshal to nil pointer: %w", ErrValueInvalid)
 			}
 
 			l, r, err := UnmarshalInt32(in)
@@ -507,7 +507,7 @@ func decRegister(e interface{}) (err error) {
 		}
 		decoderCache[t.Name()] = f
 	default:
-		return errors.New("ssob: Unknown type " + string(t.Name()))
+		return fmt.Errorf("ssob: %s: %w", string(t.Name()), ErrTypeUnknown)
 	}
 
 	return nil
@@ -540,7 +540,7 @@ func unmarshalBaseType(e interface{}, in []byte) (n int, err error) {
 	case *string:
 		return decoderCache["string"](t, in)
 	default:
-		return 0, errors.New("ssob: No base type")
+		return 0, fmt.Errorf("ssob: No base type: %w", ErrTypeUnknown)
 	}
 }
 
@@ -554,7 +554,7 @@ func unmarshal(e interface{}, in []byte) (n int, err error) {
 	t := reflect.TypeOf(e)
 	v := reflect.ValueOf(e)
 	if !v.IsValid() || t.Kind() != reflect.Ptr || v.IsNil() {
-		return 0, errors.New("ssob: Need a pointer that is fully allocated for unmarshalling")
+		return 0, fmt.Errorf("ssob: Need a pointer that is fully allocated for unmarshalling: %w", ErrValueInvalid)
 	}
 
 	p := reflect.Indirect(v)

unsafe_decoder.go

@@ -2,7 +2,7 @@ package ssob
 
 import (
 	"encoding/binary"
-	"errors"
+	"fmt"
 	"io"
 	"reflect"
 	"sync"
@@ -25,11 +25,11 @@ func (dec *UnsafeDecoder) Decode(e interface{}) (err error) {
 
 func (dec *UnsafeDecoder) DecodeValue(value reflect.Value) (err error) {
 	if value.Kind() == reflect.Invalid {
-		return errors.New("ssob: Cannot decode nil value")
+		return fmt.Errorf("ssob: Cannot decode nil: %w", ErrValueInvalid)
 	}
 
 	if value.Kind() == reflect.Ptr && value.IsNil() {
-		return errors.New("ssob: Cannot decode nil of type " + value.Type().String())
+		return fmt.Errorf("ssob: Cannot decode nil of type %s: %w", value.Type().String(), ErrValueInvalid)
 	}
 
 	dec.mutex.Lock()

unsafe_encoder.go

@@ -2,7 +2,7 @@ package ssob
 
 import (
 	"encoding/binary"
-	"errors"
+	"fmt"
 	"io"
 	"reflect"
 	"sync"
@@ -25,11 +25,11 @@ func (enc *UnsafeEncoder) Encode(e interface{}) (err error) {
 
 func (enc *UnsafeEncoder) EncodeValue(value reflect.Value) (err error) {
 	if value.Kind() == reflect.Invalid {
-		return errors.New("ssob: Cannot encode nil value")
+		return fmt.Errorf("ssob: Cannot encode nil: %w", ErrValueInvalid)
 	}
 
 	if value.Kind() == reflect.Ptr && value.IsNil() {
-		return errors.New("ssob: Cannot encode nil of type " + value.Type().String())
+		return fmt.Errorf("ssob: Cannot encode nil of type %s: %w", value.Type().String(), ErrValueInvalid)
 	}
 
 	bb, err := unsafeMarshal(value.Interface())

unsafe_marshal.go

@@ -1,7 +1,7 @@
 package ssob
 
 import (
-	"errors"
+	"fmt"
 	"reflect"
 	"unsafe"
 )
@@ -207,81 +207,85 @@ func init() {
 		if i, ok := e.(bool); ok {
 			return UnsafeMarshalBool(i), nil
 		}
-		return nil, errors.New("ssob: Incompatible type - expected bool")
+		return nil, fmt.Errorf("ssob: Incompatible type - expected bool: %w", ErrTypeMismatch)
 	})
 	RegisterUnsafeEncoder("int8", func(e interface{}) (ret []byte, err error) {
 		if i, ok := e.(int8); ok {
 			return UnsafeMarshalInt8(i), nil
 		}
-		return nil, errors.New("ssob: Incompatible type - expected int8")
+		return nil, fmt.Errorf("ssob: Incompatible type - expected int8: %w", ErrTypeMismatch)
 	})
 	RegisterUnsafeEncoder("uint8", func(e interface{}) (ret []byte, err error) {
 		if i, ok := e.(uint8); ok {
 			return UnsafeMarshalUint8(i), nil
 		}
-		return nil, errors.New("ssob: Incompatible type - expected uint8")
+		return nil, fmt.Errorf("ssob: Incompatible type - expected uint8: %w", ErrTypeMismatch)
 	})
 	RegisterUnsafeEncoder("int16", func(e interface{}) (ret []byte, err error) {
 		if i, ok := e.(int16); ok {
 			return UnsafeMarshalInt16(i), nil
 		}
-		return nil, errors.New("ssob: Incompatible type - expected int16")
+		return nil, fmt.Errorf("ssob: Incompatible type - expected int16: %w", ErrTypeMismatch)
 	})
 	RegisterUnsafeEncoder("uint16", func(e interface{}) (ret []byte, err error) {
 		if i, ok := e.(uint16); ok {
 			return UnsafeMarshalUint16(i), nil
 		}
-		return nil, errors.New("ssob: Incompatible type - expected uint16")
+		return nil, fmt.Errorf("ssob: Incompatible type - expected uint16: %w", ErrTypeMismatch)
 	})
 	RegisterUnsafeEncoder("int32", func(e interface{}) (ret []byte, err error) {
 		if i, ok := e.(int32); ok {
 			return UnsafeMarshalInt32(i), nil
 		}
-		return nil, errors.New("ssob: Incompatible type - expected int32")
+		return nil, fmt.Errorf("ssob: Incompatible type - expected int32: %w", ErrTypeMismatch)
 	})
 	RegisterUnsafeEncoder("uint32", func(e interface{}) (ret []byte, err error) {
 		if i, ok := e.(uint32); ok {
 			return UnsafeMarshalUint32(i), nil
 		}
-		return nil, errors.New("ssob: Incompatible type - expected uint32")
+		return nil, fmt.Errorf("ssob: Incompatible type - expected uint32: %w", ErrTypeMismatch)
 	})
 	RegisterUnsafeEncoder("float32", func(e interface{}) (ret []byte, err error) {
 		if i, ok := e.(float32); ok {
 			return UnsafeMarshalFloat32(i), nil
 		}
-		return nil, errors.New("ssob: Incompatible type - expected float32")
+		return nil, fmt.Errorf("ssob: Incompatible type - expected float32: %w", ErrTypeMismatch)
 	})
 	RegisterUnsafeEncoder("int64", func(e interface{}) (ret []byte, err error) {
 		if i, ok := e.(int64); ok {
 			return UnsafeMarshalInt64(i), nil
 		}
-		return nil, errors.New("ssob: Incompatible type - expected int64")
+		return nil, fmt.Errorf("ssob: Incompatible type - expected int64: %w", ErrTypeMismatch)
 	})
 	RegisterUnsafeEncoder("uint64", func(e interface{}) (ret []byte, err error) {
 		if i, ok := e.(uint64); ok {
 			return UnsafeMarshalUint64(i), nil
 		}
-		return nil, errors.New("ssob: Incompatible type - expected uint64")
+		return nil, fmt.Errorf("ssob: Incompatible type - expected uint64: %w", ErrTypeMismatch)
 	})
 	RegisterUnsafeEncoder("float64", func(e interface{}) (ret []byte, err error) {
 		if i, ok := e.(float64); ok {
 			return UnsafeMarshalFloat64(i), nil
 		}
-		return nil, errors.New("ssob: Incompatible type - expected float64")
+		return nil, fmt.Errorf("ssob: Incompatible type - expected float64: %w", ErrTypeMismatch)
 	})
 	RegisterUnsafeEncoder("string", func(e interface{}) (ret []byte, err error) {
 		if i, ok := e.(string); ok {
 			return UnsafeMarshalString(i), nil
 		}
-		return nil, errors.New("ssob: Incompatible type - expected string")
+		return nil, fmt.Errorf("ssob: Incompatible type - expected string: %w", ErrTypeMismatch)
 	})
 }
 
 func encRegisterUnsafe(e interface{}) (err error) {
 	t := reflect.TypeOf(e)
+	if t == nil {
+		return fmt.Errorf("ssob: nil type: %w", ErrTypeInvalid)
+	}
+
 	switch t.Kind() {
 	case reflect.Invalid:
-		return errors.New("ssob: Invalid type")
+		return fmt.Errorf("ssob: invalid type: %w", ErrTypeInvalid)
 	case reflect.Array:
 		f := func(e interface{}) (ret []byte, err error) {
 			v := reflect.ValueOf(e)
@@ -362,7 +366,7 @@ func encRegisterUnsafe(e interface{}) (err error) {
 			}
 		}
 		if len(mfields) == 0 {
-			return errors.New("ssob: No exported fields for " + string(t.Name()))
+			return fmt.Errorf("ssob: No exported fields for %s: %w", string(t.Name()), ErrParseFailed)
 		}
 
 		f := func(e interface{}) (ret []byte, err error) {
@@ -445,7 +449,7 @@ func encRegisterUnsafe(e interface{}) (err error) {
 		}
 		unsafeEncoderCache[t.Name()] = f
 	default:
-		return errors.New("ssob: Unknown type " + string(t.Name()))
+		return fmt.Errorf("ssob: %s: %w", string(t.Name()), ErrTypeUnknown)
 	}
 
 	return nil
@@ -478,7 +482,7 @@ func unsafeMarshalBaseType(e interface{}) (ret []byte, err error) {
 	case string:
 		return unsafeEncoderCache["string"](t)
 	default:
-		return nil, errors.New("ssob: No base type")
+		return nil, fmt.Errorf("ssob: No base type: %w", ErrTypeUnknown)
 	}
 }
 
@@ -494,7 +498,7 @@ func unsafeMarshal(e interface{}) (ret []byte, err error) {
 	switch t.Kind() {
 	case reflect.Ptr:
 		if v.IsNil() {
-			return nil, errors.New("ssob: Cannot marshal nil pointer")
+			return nil, fmt.Errorf("ssob: Cannot marshal nil pointer: %w", ErrValueInvalid)
 		}
 		p := reflect.Indirect(v)
 		return unsafeMarshal(p.Interface())

unsafe_unmarshal.go

@@ -2,26 +2,26 @@ package ssob
 
 import (
 	"encoding/binary"
-	"errors"
+	"fmt"
 	"reflect"
 	"unsafe"
 )
 
 func UnsafeUnmarshalString(in []byte) (ret string, n int, err error) {
 	if len(in) < 4 {
-		return "", 0, errors.New("ssob: Invalid input to decode string")
+		return "", 0, fmt.Errorf("ssob: Decoding string: %w", ErrTypeInvalid)
 	}
 	l := int32(binary.BigEndian.Uint32(in))
 
 	if len(in[4:]) < int(l) {
-		return "", 0, errors.New("ssob: Invalid length of string")
+		return "", 0, fmt.Errorf("ssob: Invalid length of string: %w", ErrValueInvalid)
 	}
 	return string(in[4 : l+4]), int(l) + 4, nil
 }
 
 func UnsafeUnmarshalBool(in []byte) (ret bool, n int, err error) {
 	if len(in) < 1 {
-		return false, 0, errors.New("ssob: Invalid input to decode bool")
+		return false, 0, fmt.Errorf("ssob: Decoding bool: %w", ErrTypeInvalid)
 	}
 
 	if in[0] == byte(0) {
@@ -32,7 +32,7 @@ func UnsafeUnmarshalBool(in []byte) (ret bool, n int, err error) {
 
 func UnsafeUnmarshalInt8(in []byte) (ret int8, n int, err error) {
 	if len(in) < 1 {
-		return 0, 0, errors.New("ssob: Invalid input to decode int8")
+		return 0, 0, fmt.Errorf("ssob: Decoding int8: %w", ErrTypeInvalid)
 	}
 
 	return int8(in[0]), 1, nil
@@ -40,7 +40,7 @@ func UnsafeUnmarshalInt8(in []byte) (ret int8, n int, err error) {
 
 func UnsafeUnmarshalUint8(in []byte) (ret uint8, n int, err error) {
 	if len(in) < 1 {
-		return 0, 0, errors.New("ssob: Invalid input to decode uint8")
+		return 0, 0, fmt.Errorf("ssob: Decoding uint8: %w", ErrTypeInvalid)
 	}
 
 	return uint8(in[0]), 1, nil
@@ -48,7 +48,7 @@ func UnsafeUnmarshalUint8(in []byte) (ret uint8, n int, err error) {
 
 func UnsafeUnmarshalInt16(in []byte) (ret int16, n int, err error) {
 	if len(in) < 2 {
-		return 0, 0, errors.New("ssob: Invalid input to decode int16")
+		return 0, 0, fmt.Errorf("ssob: Decoding int16: %w", ErrTypeInvalid)
 	}
 
 	var out int16
@@ -66,7 +66,7 @@ func UnsafeUnmarshalInt16(in []byte) (ret int16, n int, err error) {
 
 func UnsafeUnmarshalUint16(in []byte) (ret uint16, n int, err error) {
 	if len(in) < 2 {
-		return 0, 0, errors.New("ssob: Invalid input to decode uint16")
+		return 0, 0, fmt.Errorf("ssob: Decoding uint16: %w", ErrTypeInvalid)
 	}
 
 	var out uint16
@@ -84,7 +84,7 @@ func UnsafeUnmarshalUint16(in []byte) (ret uint16, n int, err error) {
 
 func UnsafeUnmarshalInt32(in []byte) (ret int32, n int, err error) {
 	if len(in) < 4 {
-		return 0, 0, errors.New("ssob: Invalid input to decode int32")
+		return 0, 0, fmt.Errorf("ssob: Decoding int32: %w", ErrTypeInvalid)
 	}
 
 	var out int32
@@ -106,7 +106,7 @@ func UnsafeUnmarshalInt32(in []byte) (ret int32, n int, err error) {
 
 func UnsafeUnmarshalUint32(in []byte) (ret uint32, n int, err error) {
 	if len(in) < 4 {
-		return 0, 0, errors.New("ssob: Invalid input to decode uint32")
+		return 0, 0, fmt.Errorf("ssob: Decoding uint32: %w", ErrTypeInvalid)
 	}
 
 	var out uint32
@@ -128,7 +128,7 @@ func UnsafeUnmarshalUint32(in []byte) (ret uint32, n int, err error) {
 
 func UnsafeUnmarshalFloat32(in []byte) (ret float32, n int, err error) {
 	if len(in) < 4 {
-		return 0, 0, errors.New("ssob: Invalid input to decode float32")
+		return 0, 0, fmt.Errorf("ssob: Decoding float32: %w", ErrTypeInvalid)
 	}
 
 	var out float32
@@ -150,7 +150,7 @@ func UnsafeUnmarshalFloat32(in []byte) (ret float32, n int, err error) {
 
 func UnsafeUnmarshalInt64(in []byte) (ret int64, n int, err error) {
 	if len(in) < 8 {
-		return 0, 0, errors.New("ssob: Invalid input to decode int64")
+		return 0, 0, fmt.Errorf("ssob: Decoding int64: %w", ErrTypeInvalid)
 	}
 
 	var out int64
@@ -180,7 +180,7 @@ func UnsafeUnmarshalInt64(in []byte) (ret int64, n int, err error) {
 
 func UnsafeUnmarshalUint64(in []byte) (ret uint64, n int, err error) {
 	if len(in) < 8 {
-		return 0, 0, errors.New("ssob: Invalid input to decode uint64")
+		return 0, 0, fmt.Errorf("ssob: Decoding uint64: %w", ErrTypeInvalid)
 	}
 
 	var out uint64
@@ -210,7 +210,7 @@ func UnsafeUnmarshalUint64(in []byte) (ret uint64, n int, err error) {
 
 func UnsafeUnmarshalFloat64(in []byte) (ret float64, n int, err error) {
 	if len(in) < 8 {
-		return 0, 0, errors.New("ssob: Invalid input to decode float64")
+		return 0, 0, fmt.Errorf("ssob: Decoding float64: %w", ErrTypeInvalid)
 	}
 
 	var out float64
@@ -247,92 +247,96 @@ func init() {
 			*i, n, err = UnsafeUnmarshalBool(in)
 			return n, nil
 		}
-		return 0, errors.New("ssob: Incompatible type - expected bool")
+		return 0, fmt.Errorf("ssob: Incompatible type - expected bool: %w", ErrTypeMismatch)
 	})
 	RegisterUnsafeDecoder("int8", func(e interface{}, in []byte) (n int, err error) {
 		if i, ok := e.(*int8); ok {
 			*i, n, err = UnsafeUnmarshalInt8(in)
 			return n, nil
 		}
-		return 0, errors.New("ssob: Incompatible type - expected int8")
+		return 0, fmt.Errorf("ssob: Incompatible type - expected int8: %w", ErrTypeMismatch)
 	})
 	RegisterUnsafeDecoder("uint8", func(e interface{}, in []byte) (n int, err error) {
 		if i, ok := e.(*uint8); ok {
 			*i, n, err = UnsafeUnmarshalUint8(in)
 			return n, nil
 		}
-		return 0, errors.New("ssob: Incompatible type - expected uint8")
+		return 0, fmt.Errorf("ssob: Incompatible type - expected uint8: %w", ErrTypeMismatch)
 	})
 	RegisterUnsafeDecoder("int16", func(e interface{}, in []byte) (n int, err error) {
 		if i, ok := e.(*int16); ok {
 			*i, n, err = UnsafeUnmarshalInt16(in)
 			return n, nil
 		}
-		return 0, errors.New("ssob: Incompatible type - expected int16")
+		return 0, fmt.Errorf("ssob: Incompatible type - expected int16: %w", ErrTypeMismatch)
 	})
 	RegisterUnsafeDecoder("uint16", func(e interface{}, in []byte) (n int, err error) {
 		if i, ok := e.(*uint16); ok {
 			*i, n, err = UnsafeUnmarshalUint16(in)
 			return n, nil
 		}
-		return 0, errors.New("ssob: Incompatible type - expected uint16")
+		return 0, fmt.Errorf("ssob: Incompatible type - expected uint16: %w", ErrTypeMismatch)
 	})
 	RegisterUnsafeDecoder("int32", func(e interface{}, in []byte) (n int, err error) {
 		if i, ok := e.(*int32); ok {
 			*i, n, err = UnsafeUnmarshalInt32(in)
 			return n, nil
 		}
-		return 0, errors.New("ssob: Incompatible type - expected int32")
+		return 0, fmt.Errorf("ssob: Incompatible type - expected int32: %w", ErrTypeMismatch)
 	})
 	RegisterUnsafeDecoder("uint32", func(e interface{}, in []byte) (n int, err error) {
 		if i, ok := e.(*uint32); ok {
 			*i, n, err = UnsafeUnmarshalUint32(in)
 			return n, nil
 		}
-		return 0, errors.New("ssob: Incompatible type - expected uint32")
+		return 0, fmt.Errorf("ssob: Incompatible type - expected uint32: %w", ErrTypeMismatch)
 	})
 	RegisterUnsafeDecoder("float32", func(e interface{}, in []byte) (n int, err error) {
 		if i, ok := e.(*float32); ok {
 			*i, n, err = UnsafeUnmarshalFloat32(in)
 			return n, nil
 		}
-		return 0, errors.New("ssob: Incompatible type - expected float32")
+		return 0, fmt.Errorf("ssob: Incompatible type - expected float32: %w", ErrTypeMismatch)
 	})
 	RegisterUnsafeDecoder("int64", func(e interface{}, in []byte) (n int, err error) {
 		if i, ok := e.(*int64); ok {
 			*i, n, err = UnsafeUnmarshalInt64(in)
 			return n, nil
 		}
-		return 0, errors.New("ssob: Incompatible type - expected int64")
+		return 0, fmt.Errorf("ssob: Incompatible type - expected int64: %w", ErrTypeMismatch)
 	})
 	RegisterUnsafeDecoder("uint64", func(e interface{}, in []byte) (n int, err error) {
 		if i, ok := e.(*uint64); ok {
 			*i, n, err = UnsafeUnmarshalUint64(in)
 			return n, nil
 		}
-		return 0, errors.New("ssob: Incompatible type - expected uint64")
+		return 0, fmt.Errorf("ssob: Incompatible type - expected uint64: %w", ErrTypeMismatch)
 	})
 	RegisterUnsafeDecoder("float64", func(e interface{}, in []byte) (n int, err error) {
 		if i, ok := e.(*float64); ok {
 			*i, n, err = UnsafeUnmarshalFloat64(in)
 			return n, nil
 		}
-		return 0, errors.New("ssob: Incompatible type - expected float64")
+		return 0, fmt.Errorf("ssob: Incompatible type - expected float64: %w", ErrTypeMismatch)
 	})
 	RegisterUnsafeDecoder("string", func(e interface{}, in []byte) (n int, err error) {
 		if i, ok := e.(*string); ok {
 			*i, n, err = UnsafeUnmarshalString(in)
 			return n, nil
 		}
-		return 0, errors.New("ssob: Incompatible type - expected string")
+		return 0, fmt.Errorf("ssob: Incompatible type - expected string: %w", ErrTypeMismatch)
 	})
 }
 
 func decRegisterUnsafe(e interface{}) (err error) {
 	t := reflect.TypeOf(e)
+	if t == nil {
+		return fmt.Errorf("ssob: nil type: %w", ErrTypeInvalid)
+	}
+
 	switch t.Kind() {
 	case reflect.Invalid:
-		return errors.New("ssob: Invalid type")
+		return fmt.Errorf("ssob: invalid type: %w", ErrTypeInvalid)
 	case reflect.Array:
 		f := func(e interface{}, in []byte) (n int, err error) {
 			t := reflect.TypeOf(e)
@@ -340,7 +344,7 @@ func decRegisterUnsafe(e interface{}) (err error) {
 			pos := 0
 
 			if t.Kind() != reflect.Ptr || v.IsNil() {
-				return 0, errors.New("ssob: Cannot unmarshal to nil pointer")
+				return 0, fmt.Errorf("ssob: Cannot unmarshal to nil pointer: %w", ErrValueInvalid)
 			}
 
 			l, r, err := UnsafeUnmarshalInt32(in)
@@ -351,7 +355,7 @@ func decRegisterUnsafe(e interface{}) (err error) {
 
 			ti := v.Elem()
 			if int(l) != ti.Len() {
-				return pos, errors.New("ssob: Invalid array length. Expected " + string(l) + " got " + string(ti.Len()))
+				return pos, fmt.Errorf("ssob: Invalid array length. Expected %s got %s: %w", string(l), string(ti.Len()), ErrValueInvalid)
 			}
 			for i := 0; i < int(l); i++ {
 				e := reflect.New(reflect.TypeOf(ti.Interface()).Elem())
@@ -372,7 +376,7 @@ func decRegisterUnsafe(e interface{}) (err error) {
 			pos := 0
 
 			if t.Kind() != reflect.Ptr || v.IsNil() {
-				return 0, errors.New("ssob: Cannot unmarshal to nil pointer")
+				return 0, fmt.Errorf("ssob: Cannot unmarshal to nil pointer: %w", ErrValueInvalid)
 			}
 
 			l, r, err := UnsafeUnmarshalInt32(in)
@@ -405,7 +409,7 @@ func decRegisterUnsafe(e interface{}) (err error) {
 			}
 		}
 		if len(mfields) == 0 {
-			return errors.New("ssob: No exported fields for " + string(t.Name()))
+			return fmt.Errorf("ssob: No exported fields for %s: %w", string(t.Name()), ErrParseFailed)
 		}
 
 		f := func(e interface{}, in []byte) (n int, err error) {
@@ -414,7 +418,7 @@ func decRegisterUnsafe(e interface{}) (err error) {
 			pos := 0
 
 			if t.Kind() != reflect.Ptr || v.IsNil() {
-				return 0, errors.New("ssob: Cannot unmarshal to nil pointer")
+				return 0, fmt.Errorf("ssob: Cannot unmarshal to nil pointer: %w", ErrValueInvalid)
 			}
 
 			vi := reflect.Indirect(v)
@@ -436,7 +440,7 @@ func decRegisterUnsafe(e interface{}) (err error) {
 			pos := 0
 
 			if t.Kind() != reflect.Ptr || v.IsNil() {
-				return 0, errors.New("ssob: Cannot unmarshal to nil pointer")
+				return 0, fmt.Errorf("ssob: Cannot unmarshal to nil pointer: %w", ErrValueInvalid)
 			}
 
 			l, r, err := UnsafeUnmarshalInt32(in)
@@ -629,7 +633,7 @@ func decRegisterUnsafe(e interface{}) (err error) {
 		}
 		unsafeDecoderCache[t.Name()] = f
 	default:
-		return errors.New("ssob: Unknown type " + string(t.Name()))
+		return fmt.Errorf("ssob: %s: %w", string(t.Name()), ErrTypeUnknown)
 	}
 
 	return nil
@@ -662,7 +666,7 @@ func unsafeUnmarshalBaseType(e interface{}, in []byte) (n int, err error) {
 	case *string:
 		return unsafeDecoderCache["string"](t, in)
 	default:
-		return 0, errors.New("ssob: No base type")
+		return 0, fmt.Errorf("ssob: No base type: %w", ErrTypeUnknown)
 	}
 }
 
@@ -676,7 +680,7 @@ func unsafeUnmarshal(e interface{}, in []byte) (n int, err error) {
 	t := reflect.TypeOf(e)
 	v := reflect.ValueOf(e)
 	if t.Kind() != reflect.Ptr || v.IsNil() {
-		return 0, errors.New("ssob: Need a pointer that is fully allocated for unmarshalling")
+		return 0, fmt.Errorf("ssob: Need a pointer that is fully allocated for unmarshalling: %w", ErrValueInvalid)
 	}
 
 	p := reflect.Indirect(v)