From 8463646eb00c73e8a79bb2c578195cfe61538af9 Mon Sep 17 00:00:00 2001
From: Masaaki Goshima <goccy54@gmail.com>
Date: Thu, 27 Aug 2020 21:01:53 +0900
Subject: [PATCH] Fix encoding for Indent/MarshalIndent

---
 encode_vm.go | 28 +++++++++++++++++++++-------
 indent.go    |  6 ++++--
 2 files changed, 25 insertions(+), 9 deletions(-)

diff --git a/encode_vm.go b/encode_vm.go
index 8714a4c..9efcb3b 100644
--- a/encode_vm.go
+++ b/encode_vm.go
@@ -147,12 +147,22 @@ func (e *Encoder) run(code *opcode) error {
 				)
 			}
 			var buf bytes.Buffer
-			if err := compact(&buf, b, true); err != nil {
-				return err
+			if e.enabledIndent {
+				if err := encodeWithIndent(
+					&buf,
+					b,
+					string(e.prefix)+string(bytes.Repeat(e.indentStr, code.indent)),
+					string(e.indentStr),
+				); err != nil {
+					return err
+				}
+			} else {
+				if err := compact(&buf, b, true); err != nil {
+					return err
+				}
 			}
 			e.encodeBytes(buf.Bytes())
 			code = code.next
-			code.ptr = ptr
 		case opMarshalText:
 			ptr := code.ptr
 			isPtr := code.typ.Kind() == reflect.Ptr
@@ -276,7 +286,7 @@ func (e *Encoder) run(code *opcode) error {
 			} else {
 				e.encodeByte('\n')
 				e.encodeIndent(code.indent)
-				e.encodeBytes([]byte{']'})
+				e.encodeByte(']')
 				code = c.end.next
 			}
 		case opArrayHead:
@@ -1352,15 +1362,19 @@ func (e *Encoder) run(code *opcode) error {
 			field := code.toStructFieldCode()
 			ptr := field.ptr
 			if ptr == 0 {
-				e.encodeIndent(code.indent)
-				e.encodeNull()
+				if code.op == opStructFieldPtrHeadIntIndent {
+					e.encodeIndent(code.indent)
+					e.encodeNull()
+				} else {
+					e.encodeBytes([]byte{'{', '}'})
+				}
 				code = field.end
 			} else {
 				e.encodeBytes([]byte{'{', '\n'})
 				e.encodeIndent(code.indent + 1)
 				e.encodeBytes(field.key)
 				e.encodeByte(' ')
-				e.encodeInt(e.ptrToInt(ptr))
+				e.encodeInt(e.ptrToInt(ptr + field.offset))
 				field.nextField.ptr = ptr
 				code = field.next
 			}
diff --git a/indent.go b/indent.go
index fc46ca8..a6a0329 100644
--- a/indent.go
+++ b/indent.go
@@ -52,9 +52,10 @@ func encodeWithIndent(dst *bytes.Buffer, src []byte, prefix, indentStr string) e
 			if indentNum < 0 {
 				return errInvalidCharacter('}', "}", cursor)
 			}
-			b := []byte{'\n', c}
+			b := []byte{'\n'}
 			b = append(b, prefix...)
 			b = append(b, bytes.Repeat(indentBytes, indentNum)...)
+			b = append(b, c)
 			if _, err := dst.Write(b); err != nil {
 				return err
 			}
@@ -78,9 +79,10 @@ func encodeWithIndent(dst *bytes.Buffer, src []byte, prefix, indentStr string) e
 			if indentNum < 0 {
 				return errInvalidCharacter(']', "]", cursor)
 			}
-			b := []byte{'\n', c}
+			b := []byte{'\n'}
 			b = append(b, prefix...)
 			b = append(b, bytes.Repeat(indentBytes, indentNum)...)
+			b = append(b, c)
 			if _, err := dst.Write(b); err != nil {
 				return err
 			}