From 23081eadad30d6704f8ff278359501b6dcc4347c Mon Sep 17 00:00:00 2001
From: Masaaki Goshima <goccy54@gmail.com>
Date: Fri, 7 May 2021 23:15:16 +0900
Subject: [PATCH] Fix calculating of length for stream decoder

---
 decode_map.go    | 12 +++---------
 decode_stream.go |  9 +++++++++
 decode_string.go |  4 +++-
 3 files changed, 15 insertions(+), 10 deletions(-)

diff --git a/decode_map.go b/decode_map.go
index c09e2a2..a3fa291 100644
--- a/decode_map.go
+++ b/decode_map.go
@@ -68,10 +68,7 @@ func (d *mapDecoder) decodeStream(s *stream, depth int64, p unsafe.Pointer) erro
 			return err
 		}
 		s.skipWhiteSpace()
-		if s.char() == nul {
-			s.read()
-		}
-		if s.char() != ':' {
+		if !s.equalChar(':') {
 			return errExpected("colon after object key", s.totalOffset())
 		}
 		s.cursor++
@@ -81,15 +78,12 @@ func (d *mapDecoder) decodeStream(s *stream, depth int64, p unsafe.Pointer) erro
 		}
 		mapassign(d.mapType, mapValue, k, v)
 		s.skipWhiteSpace()
-		if s.char() == nul {
-			s.read()
-		}
-		if s.char() == '}' {
+		if s.equalChar('}') {
 			**(**unsafe.Pointer)(unsafe.Pointer(&p)) = mapValue
 			s.cursor++
 			return nil
 		}
-		if s.char() != ',' {
+		if !s.equalChar(',') {
 			return errExpected("comma after object value", s.totalOffset())
 		}
 	}
diff --git a/decode_stream.go b/decode_stream.go
index 0d3e263..ba874e5 100644
--- a/decode_stream.go
+++ b/decode_stream.go
@@ -49,6 +49,15 @@ func (s *stream) char() byte {
 	return s.buf[s.cursor]
 }
 
+func (s *stream) equalChar(c byte) bool {
+	cur := s.buf[s.cursor]
+	if cur == nul {
+		s.read()
+		cur = s.buf[s.cursor]
+	}
+	return cur == c
+}
+
 func (s *stream) stat() ([]byte, int64, unsafe.Pointer) {
 	return s.buf, s.cursor, (*sliceHeader)(unsafe.Pointer(&s.buf)).data
 }
diff --git a/decode_string.go b/decode_string.go
index 6b97c52..fc9aae2 100644
--- a/decode_string.go
+++ b/decode_string.go
@@ -127,7 +127,8 @@ func decodeUnicode(s *stream) error {
 	unicode := []byte(string(r))
 	unicodeLen := int64(len(unicode))
 	s.buf = append(append(s.buf[:s.cursor-1], unicode...), s.buf[s.cursor+offset:]...)
-	s.length = int64(len(s.buf))
+	unicodeOrgLen := offset - 1
+	s.length = s.length - (backSlashAndULen + (unicodeOrgLen - unicodeLen))
 	s.cursor = s.cursor - backSlashAndULen + unicodeLen
 	return nil
 }
@@ -163,6 +164,7 @@ RETRY:
 		return errUnexpectedEndOfJSON("string", s.totalOffset())
 	}
 	s.buf = append(s.buf[:s.cursor-1], s.buf[s.cursor:]...)
+	s.length--
 	s.cursor--
 	return nil
 }