improve fast equal API, add bech32 encoding handling

pkg/encoders/bech32encoding/tlv/tlv.go

@@ -0,0 +1,41 @@
+// Package tlv implements a simple Type Length Value encoder for nostr NIP-19
+// bech32 encoded entities. The format is generic and could also be used for any
+// TLV use case where fields are less than 255 bytes.
+package tlv
+
+import (
+	"io"
+)
+
+const (
+	Default byte = iota
+	Relay
+	Author
+	Kind
+)
+
+// ReadEntry reads a TLV value from a bech32 encoded nostr entity.
+func ReadEntry(buf io.Reader) (typ uint8, value []byte) {
+	var err error
+	t := make([]byte, 1)
+	if _, err = buf.Read(t); err != nil {
+		return
+	}
+	typ = t[0]
+	l := make([]byte, 1)
+	if _, err = buf.Read(l); err != nil {
+		return
+	}
+	length := int(l[0])
+	value = make([]byte, length)
+	if _, err = buf.Read(value); err != nil {
+		// nil value signals end of data or error
+		value = nil
+	}
+	return
+}
+
+// WriteEntry writes a TLV value for a bech32 encoded nostr entity.
+func WriteEntry(buf io.Writer, typ uint8, value []byte) {
+	buf.Write(append([]byte{typ, byte(len(value))}, value...))
+}