From dd1b8fd9c96c5df276978e772c3579a9fa706fff Mon Sep 17 00:00:00 2001
From: Tnze <cjd001113@outlook.com>
Date: Thu, 27 May 2021 01:33:08 +0800
Subject: [PATCH] Support TAG_Byte_Array, TAG_Int_Array and TAG_Long_Array

---
 nbt/snbt_decode.go       | 46 +++++++++++++++++++++++++++++++++++++++-
 nbt/snbt_scanner.go      |  9 +++++++-
 nbt/snbt_scanner_test.go |  1 +
 3 files changed, 54 insertions(+), 2 deletions(-)

diff --git a/nbt/snbt_decode.go b/nbt/snbt_decode.go
index 1b26706..0ffa2c8 100644
--- a/nbt/snbt_decode.go
+++ b/nbt/snbt_decode.go
@@ -121,7 +121,49 @@ func writeListOrArray(e *Encoder, d *decodeState, tagName string) error {
 		d.scanWhile(scanContinue)
 		literal := d.data[start:d.readIndex()]
 		if d.opcode == scanListType { // TAG_X_Array
-			//listType := literal[0]
+			var elemType byte
+			switch literal[0] {
+			case 'B':
+				e.writeTag(TagByteArray, tagName)
+				elemType = TagByte
+			case 'I':
+				e.writeTag(TagIntArray, tagName)
+				elemType = TagInt
+			case 'L':
+				e.writeTag(TagLongArray, tagName)
+				elemType = TagLong
+			}
+			for {
+				d.scanNext()
+				if d.opcode == scanSkipSpace {
+					d.scanWhile(scanSkipSpace)
+				}
+				if d.opcode == scanEndValue { // ]
+					break
+				}
+				if d.opcode != scanBeginLiteral {
+					return errors.New("not literal in Array")
+				}
+				start := d.readIndex()
+
+				d.scanWhile(scanContinue)
+				literal := d.data[start:d.readIndex()]
+				tagType, litVal := parseLiteral(literal)
+				if tagType != elemType {
+					return errors.New("unexpected element type in TAG_Array")
+				}
+				switch elemType {
+				case TagByte:
+					e2.w.Write([]byte{byte(litVal.(int8))})
+				case TagInt:
+					e2.writeInt32(litVal.(int32))
+				case TagLong:
+					e2.writeInt64(litVal.(int64))
+				}
+				count++
+			}
+			e.writeInt32(int32(count))
+			e.w.Write(buf.Bytes())
 			break
 		}
 		if d.opcode != scanListValue { // TAG_List<TAG_String>
@@ -157,6 +199,8 @@ func writeListOrArray(e *Encoder, d *decodeState, tagName string) error {
 		e.writeListHeader(tagType, tagName, count)
 		e.w.Write(buf.Bytes())
 	case scanBeginList: // TAG_List<TAG_List>
+		e.writeListHeader(TagList, tagName, count)
+		e.w.Write(buf.Bytes())
 	case scanBeginCompound: // TAG_List<TAG_Compound>
 		for {
 			if d.opcode == scanSkipSpace {
diff --git a/nbt/snbt_scanner.go b/nbt/snbt_scanner.go
index d97e8d2..44c043f 100644
--- a/nbt/snbt_scanner.go
+++ b/nbt/snbt_scanner.go
@@ -249,12 +249,19 @@ func (s *scanner) stateListOrArray(c byte) int {
 
 func (s *scanner) stateListOrArrayT(c byte) int {
 	if c == ';' {
-		s.step = s.stateBeginValue
+		s.step = s.stateArrayT
 		return scanListType
 	}
 	return s.stateInUnquotedString(c)
 }
 
+func (s *scanner) stateArrayT(c byte) int {
+	if c == ']' { // empty array
+		return scanEndValue
+	}
+	return s.stateBeginValue(c)
+}
+
 func (s *scanner) stateNeg(c byte) int {
 	if isNumber(c) {
 		s.step = s.stateNum0
diff --git a/nbt/snbt_scanner_test.go b/nbt/snbt_scanner_test.go
index ddbb675..cf5de10 100644
--- a/nbt/snbt_scanner_test.go
+++ b/nbt/snbt_scanner_test.go
@@ -67,6 +67,7 @@ func TestSNBT_list(t *testing.T) {
 		`[{}, {}, {"a\"b":520}]`, // List of Compound
 		`[B,C,D]`, `[L, "abc"]`,  // List of string (like array)
 		`[B; 01B, 02B, 3B, 10B, 127B]`, // Array
+		`[I;]`,                         // Empty array
 	}
 	var s scanner
 	scan := func(str string) bool {