stream.go raw
1 package jsoniter
2
3 import (
4 "io"
5 )
6
7 // stream is a io.Writer like object, with JSON specific write functions.
8 // Error is not returned as return value, but stored as Error member on this stream instance.
9 type Stream struct {
10 cfg *frozenConfig
11 out io.Writer
12 buf []byte
13 Error error
14 indention int
15 Attachment interface{} // open for customized encoder
16 }
17
18 // NewStream create new stream instance.
19 // cfg can be jsoniter.ConfigDefault.
20 // out can be nil if write to internal buffer.
21 // bufSize is the initial size for the internal buffer in bytes.
22 func NewStream(cfg API, out io.Writer, bufSize int) *Stream {
23 return &Stream{
24 cfg: cfg.(*frozenConfig),
25 out: out,
26 buf: make([]byte, 0, bufSize),
27 Error: nil,
28 indention: 0,
29 }
30 }
31
32 // Pool returns a pool can provide more stream with same configuration
33 func (stream *Stream) Pool() StreamPool {
34 return stream.cfg
35 }
36
37 // Reset reuse this stream instance by assign a new writer
38 func (stream *Stream) Reset(out io.Writer) {
39 stream.out = out
40 stream.buf = stream.buf[:0]
41 }
42
43 // Available returns how many bytes are unused in the buffer.
44 func (stream *Stream) Available() int {
45 return cap(stream.buf) - len(stream.buf)
46 }
47
48 // Buffered returns the number of bytes that have been written into the current buffer.
49 func (stream *Stream) Buffered() int {
50 return len(stream.buf)
51 }
52
53 // Buffer if writer is nil, use this method to take the result
54 func (stream *Stream) Buffer() []byte {
55 return stream.buf
56 }
57
58 // SetBuffer allows to append to the internal buffer directly
59 func (stream *Stream) SetBuffer(buf []byte) {
60 stream.buf = buf
61 }
62
63 // Write writes the contents of p into the buffer.
64 // It returns the number of bytes written.
65 // If nn < len(p), it also returns an error explaining
66 // why the write is short.
67 func (stream *Stream) Write(p []byte) (nn int, err error) {
68 stream.buf = append(stream.buf, p...)
69 if stream.out != nil {
70 nn, err = stream.out.Write(stream.buf)
71 stream.buf = stream.buf[nn:]
72 return
73 }
74 return len(p), nil
75 }
76
77 // WriteByte writes a single byte.
78 func (stream *Stream) writeByte(c byte) {
79 stream.buf = append(stream.buf, c)
80 }
81
82 func (stream *Stream) writeTwoBytes(c1 byte, c2 byte) {
83 stream.buf = append(stream.buf, c1, c2)
84 }
85
86 func (stream *Stream) writeThreeBytes(c1 byte, c2 byte, c3 byte) {
87 stream.buf = append(stream.buf, c1, c2, c3)
88 }
89
90 func (stream *Stream) writeFourBytes(c1 byte, c2 byte, c3 byte, c4 byte) {
91 stream.buf = append(stream.buf, c1, c2, c3, c4)
92 }
93
94 func (stream *Stream) writeFiveBytes(c1 byte, c2 byte, c3 byte, c4 byte, c5 byte) {
95 stream.buf = append(stream.buf, c1, c2, c3, c4, c5)
96 }
97
98 // Flush writes any buffered data to the underlying io.Writer.
99 func (stream *Stream) Flush() error {
100 if stream.out == nil {
101 return nil
102 }
103 if stream.Error != nil {
104 return stream.Error
105 }
106 _, err := stream.out.Write(stream.buf)
107 if err != nil {
108 if stream.Error == nil {
109 stream.Error = err
110 }
111 return err
112 }
113 stream.buf = stream.buf[:0]
114 return nil
115 }
116
117 // WriteRaw write string out without quotes, just like []byte
118 func (stream *Stream) WriteRaw(s string) {
119 stream.buf = append(stream.buf, s...)
120 }
121
122 // WriteNil write null to stream
123 func (stream *Stream) WriteNil() {
124 stream.writeFourBytes('n', 'u', 'l', 'l')
125 }
126
127 // WriteTrue write true to stream
128 func (stream *Stream) WriteTrue() {
129 stream.writeFourBytes('t', 'r', 'u', 'e')
130 }
131
132 // WriteFalse write false to stream
133 func (stream *Stream) WriteFalse() {
134 stream.writeFiveBytes('f', 'a', 'l', 's', 'e')
135 }
136
137 // WriteBool write true or false into stream
138 func (stream *Stream) WriteBool(val bool) {
139 if val {
140 stream.WriteTrue()
141 } else {
142 stream.WriteFalse()
143 }
144 }
145
146 // WriteObjectStart write { with possible indention
147 func (stream *Stream) WriteObjectStart() {
148 stream.indention += stream.cfg.indentionStep
149 stream.writeByte('{')
150 stream.writeIndention(0)
151 }
152
153 // WriteObjectField write "field": with possible indention
154 func (stream *Stream) WriteObjectField(field string) {
155 stream.WriteString(field)
156 if stream.indention > 0 {
157 stream.writeTwoBytes(':', ' ')
158 } else {
159 stream.writeByte(':')
160 }
161 }
162
163 // WriteObjectEnd write } with possible indention
164 func (stream *Stream) WriteObjectEnd() {
165 stream.writeIndention(stream.cfg.indentionStep)
166 stream.indention -= stream.cfg.indentionStep
167 stream.writeByte('}')
168 }
169
170 // WriteEmptyObject write {}
171 func (stream *Stream) WriteEmptyObject() {
172 stream.writeByte('{')
173 stream.writeByte('}')
174 }
175
176 // WriteMore write , with possible indention
177 func (stream *Stream) WriteMore() {
178 stream.writeByte(',')
179 stream.writeIndention(0)
180 }
181
182 // WriteArrayStart write [ with possible indention
183 func (stream *Stream) WriteArrayStart() {
184 stream.indention += stream.cfg.indentionStep
185 stream.writeByte('[')
186 stream.writeIndention(0)
187 }
188
189 // WriteEmptyArray write []
190 func (stream *Stream) WriteEmptyArray() {
191 stream.writeTwoBytes('[', ']')
192 }
193
194 // WriteArrayEnd write ] with possible indention
195 func (stream *Stream) WriteArrayEnd() {
196 stream.writeIndention(stream.cfg.indentionStep)
197 stream.indention -= stream.cfg.indentionStep
198 stream.writeByte(']')
199 }
200
201 func (stream *Stream) writeIndention(delta int) {
202 if stream.indention == 0 {
203 return
204 }
205 stream.writeByte('\n')
206 toWrite := stream.indention - delta
207 for i := 0; i < toWrite; i++ {
208 stream.buf = append(stream.buf, ' ')
209 }
210 }
211