add WriteCloser

README.md

@@ -10,18 +10,18 @@ The 3D Manufacturing Format (3MF) is a 3D printing format that allows design app
 
 ## Features
 
-* High parsing speed and moderate memory consumption
-* Complete 3MF Core spec implementation.
-* Clean API.
-* STL importer
-* Spec conformance validation
-* Robust implementation with full coverage and validated against real cases.
-* Extensions
-  * Support custom and private extensions.
-  * spec_production.
-  * spec_slice.
-  * spec_beamlattice.
-  * spec_materials, missing the display resources.
+- High parsing speed and moderate memory consumption
+- Complete 3MF Core spec implementation.
+- Clean API.
+- STL importer
+- Spec conformance validation
+- Robust implementation with full coverage and validated against real cases.
+- Extensions
+  - Support custom and private extensions.
+  - spec_production.
+  - spec_slice.
+  - spec_beamlattice.
+  - spec_materials, missing the display resources.
 
 ## Examples
 
@@ -93,9 +93,10 @@ import (
 )
 
 func main() {
-    file := os.Create("/testdata/cube.3mf")
     model := new(go3mf.Model)
-    go3mf.NewEncoder(file).Encode(model)
+    w, _ := go3mf.CreateWriter("/testdata/cube.3mf")
+    w.Encode(model)
+    w.Close()
 }
 ```
 
@@ -121,7 +122,7 @@ func main() {
     r, _ := go3mf.OpenReader("/testdata/cube.3mf")
     r.Decode(model)
     fmt.Println(production.GetBuildAttr(&model.Build).UUID)
-   
+
     model.Resources.Assets = append(model.Resources.Assets, &materials.ColorGroup{
       ID: 10, Colors: []color.RGBA{{R: 255, G: 255, B: 255, A: 255}},
     }

encoder.go

@@ -8,6 +8,7 @@ import (
 	"bytes"
 	"encoding/xml"
 	"io"
+	"os"
 	"sort"
 	"strconv"
 	"strings"
@@ -93,6 +94,29 @@ func MarshalModel(m *Model) ([]byte, error) {
 	return b.Bytes(), nil
 }
 
+// WriteCloser wrapps an Encoder than can be closed.
+type WriteCloser struct {
+	Encoder
+	f *os.File
+}
+
+// Close closes the 3MF file, rendering it unusable for I/O.
+func (w *WriteCloser) Close() error {
+	return w.f.Close()
+}
+
+// CreateWriter will create the 3MF file specified by name and return a WriteCloser.
+func CreateWriter(name string) (*WriteCloser, error) {
+	f, err := os.Create(name)
+	if err != nil {
+		return nil, err
+	}
+	return &WriteCloser{
+		Encoder: *NewEncoder(f),
+		f:       f,
+	}, nil
+}
+
 // An Encoder writes Model data to an output stream.
 //
 // See the documentation for strconv.FormatFloat for details about the FloatPrecision behaviour.

read.go

@@ -38,8 +38,8 @@ type packageReader interface {
 
 // ReadCloser wrapps a Decoder than can be closed.
 type ReadCloser struct {
+	Decoder
 	f *os.File
-	*Decoder
 }
 
 // OpenReader will open the 3MF file specified by name and return a ReadCloser.
@@ -53,7 +53,7 @@ func OpenReader(name string) (*ReadCloser, error) {
 		f.Close()
 		return nil, err
 	}
-	return &ReadCloser{f: f, Decoder: NewDecoder(f, fi.Size())}, nil
+	return &ReadCloser{f: f, Decoder: *NewDecoder(f, fi.Size())}, nil
 }
 
 // Close closes the 3MF file, rendering it unusable for I/O.