Added base64 support

pkg/yqlib/decoder_base64.go

@@ -0,0 +1,44 @@
+package yqlib
+
+import (
+	"bytes"
+	"encoding/base64"
+	"io"
+
+	yaml "gopkg.in/yaml.v3"
+)
+
+type base64Decoder struct {
+	reader   io.Reader
+	finished bool
+	encoding base64.Encoding
+}
+
+func NewBase64Decoder() Decoder {
+	return &base64Decoder{finished: false, encoding: *base64.StdEncoding}
+}
+
+func (dec *base64Decoder) Init(reader io.Reader) {
+	dec.reader = reader
+	dec.finished = false
+}
+
+func (dec *base64Decoder) Decode(rootYamlNode *yaml.Node) error {
+	if dec.finished {
+		return io.EOF
+	}
+	base64Reader := base64.NewDecoder(&dec.encoding, dec.reader)
+	buf := new(bytes.Buffer)
+
+	if _, err := buf.ReadFrom(base64Reader); err != nil {
+		return err
+	}
+	if buf.Len() == 0 {
+		dec.finished = true
+		return io.EOF
+	}
+	rootYamlNode.Kind = yaml.ScalarNode
+	rootYamlNode.Tag = "!!str"
+	rootYamlNode.Value = buf.String()
+	return nil
+}