Merge pull request #82 from elee1766/grow

add Grow function

enc.go

@@ -59,6 +59,11 @@ func (e *Encoder) ResetWriter(out io.Writer) {
 	e.first = e.first[:0]
 }
 
+// Grow grows the underlying buffer
+func (e *Encoder) Grow(n int) {
+	e.w.Grow(n)
+}
+
 // Bytes returns underlying buffer.
 func (e Encoder) Bytes() []byte { return e.w.Buf }
 

enc_test.go

@@ -32,6 +32,22 @@ func requireCompat(t *testing.T, cb func(*Encoder), v any) {
 	testEncoderModes(t, cb, string(buf))
 }
 
+func TestEncoderGrow(t *testing.T) {
+	should := require.New(t)
+	e := &Encoder{}
+	should.Equal(0, len(e.Bytes()))
+	should.Equal(0, cap(e.Bytes()))
+	e.Grow(1024)
+	should.Equal(0, len(e.Bytes()))
+	should.Equal(1024, cap(e.Bytes()))
+	e.Grow(512)
+	should.Equal(0, len(e.Bytes()))
+	should.Equal(1024, cap(e.Bytes()))
+	e.Grow(4096)
+	should.Equal(0, len(e.Bytes()))
+	should.Equal(4096, cap(e.Bytes()))
+}
+
 func TestEncoderByteShouldGrowBuffer(t *testing.T) {
 	should := require.New(t)
 	e := GetEncoder()

w.go

@@ -1,6 +1,9 @@
 package jx
 
-import "io"
+import (
+	"bytes"
+	"io"
+)
 
 // Writer writes json tokens to underlying buffer.
 //
@@ -51,6 +54,15 @@ func (w *Writer) ResetWriter(out io.Writer) {
 	w.stream.Reset(out)
 }
 
+// Grow grows the underlying buffer.
+//
+// Calls (*bytes.Buffer).Grow(n int) on w.Buf.
+func (w *Writer) Grow(n int) {
+	buf := bytes.NewBuffer(w.Buf)
+	buf.Grow(n)
+	w.Buf = buf.Bytes()
+}
+
 // byte writes a single byte.
 func (w *Writer) byte(c byte) (fail bool) {
 	if w.stream == nil {

w_test.go

@@ -23,3 +23,19 @@ func TestWriter_String(t *testing.T) {
 	w.True()
 	require.Equal(t, "true", w.String())
 }
+
+func TestWriter_Grow(t *testing.T) {
+	should := require.New(t)
+	e := &Writer{}
+	should.Equal(0, len(e.Buf))
+	should.Equal(0, cap(e.Buf))
+	e.Grow(1024)
+	should.Equal(0, len(e.Buf))
+	should.Equal(1024, cap(e.Buf))
+	e.Grow(512)
+	should.Equal(0, len(e.Buf))
+	should.Equal(1024, cap(e.Buf))
+	e.Grow(4096)
+	should.Equal(0, len(e.Buf))
+	should.Equal(4096, cap(e.Buf))
+}