DockerCLI/vendor/github.com/json-iterator/go/feature_stream.go

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package jsoniter
import (
"io"
)
// Stream is a io.Writer like object, with JSON specific write functions.
// Error is not returned as return value, but stored as Error member on this stream instance.
type Stream struct {
cfg *frozenConfig
out io.Writer
buf []byte
n int
Error error
indention int
}
// NewStream create new stream instance.
// cfg can be jsoniter.ConfigDefault.
// out can be nil if write to internal buffer.
// bufSize is the initial size for the internal buffer in bytes.
func NewStream(cfg API, out io.Writer, bufSize int) *Stream {
return &Stream{
cfg: cfg.(*frozenConfig),
out: out,
buf: make([]byte, bufSize),
n: 0,
Error: nil,
indention: 0,
}
}
// Pool returns a pool can provide more stream with same configuration
func (stream *Stream) Pool() StreamPool {
return stream.cfg
}
// Reset reuse this stream instance by assign a new writer
func (stream *Stream) Reset(out io.Writer) {
stream.out = out
stream.n = 0
}
// Available returns how many bytes are unused in the buffer.
func (stream *Stream) Available() int {
return len(stream.buf) - stream.n
}
// Buffered returns the number of bytes that have been written into the current buffer.
func (stream *Stream) Buffered() int {
return stream.n
}
// Buffer if writer is nil, use this method to take the result
func (stream *Stream) Buffer() []byte {
return stream.buf[:stream.n]
}
// Write writes the contents of p into the buffer.
// It returns the number of bytes written.
// If nn < len(p), it also returns an error explaining
// why the write is short.
func (stream *Stream) Write(p []byte) (nn int, err error) {
for len(p) > stream.Available() && stream.Error == nil {
if stream.out == nil {
stream.growAtLeast(len(p))
} else {
var n int
if stream.Buffered() == 0 {
// Large write, empty buffer.
// Write directly from p to avoid copy.
n, stream.Error = stream.out.Write(p)
} else {
n = copy(stream.buf[stream.n:], p)
stream.n += n
stream.Flush()
}
nn += n
p = p[n:]
}
}
if stream.Error != nil {
return nn, stream.Error
}
n := copy(stream.buf[stream.n:], p)
stream.n += n
nn += n
return nn, nil
}
// WriteByte writes a single byte.
func (stream *Stream) writeByte(c byte) {
if stream.Error != nil {
return
}
if stream.Available() < 1 {
stream.growAtLeast(1)
}
stream.buf[stream.n] = c
stream.n++
}
func (stream *Stream) writeTwoBytes(c1 byte, c2 byte) {
if stream.Error != nil {
return
}
if stream.Available() < 2 {
stream.growAtLeast(2)
}
stream.buf[stream.n] = c1
stream.buf[stream.n+1] = c2
stream.n += 2
}
func (stream *Stream) writeThreeBytes(c1 byte, c2 byte, c3 byte) {
if stream.Error != nil {
return
}
if stream.Available() < 3 {
stream.growAtLeast(3)
}
stream.buf[stream.n] = c1
stream.buf[stream.n+1] = c2
stream.buf[stream.n+2] = c3
stream.n += 3
}
func (stream *Stream) writeFourBytes(c1 byte, c2 byte, c3 byte, c4 byte) {
if stream.Error != nil {
return
}
if stream.Available() < 4 {
stream.growAtLeast(4)
}
stream.buf[stream.n] = c1
stream.buf[stream.n+1] = c2
stream.buf[stream.n+2] = c3
stream.buf[stream.n+3] = c4
stream.n += 4
}
func (stream *Stream) writeFiveBytes(c1 byte, c2 byte, c3 byte, c4 byte, c5 byte) {
if stream.Error != nil {
return
}
if stream.Available() < 5 {
stream.growAtLeast(5)
}
stream.buf[stream.n] = c1
stream.buf[stream.n+1] = c2
stream.buf[stream.n+2] = c3
stream.buf[stream.n+3] = c4
stream.buf[stream.n+4] = c5
stream.n += 5
}
// Flush writes any buffered data to the underlying io.Writer.
func (stream *Stream) Flush() error {
if stream.out == nil {
return nil
}
if stream.Error != nil {
return stream.Error
}
if stream.n == 0 {
return nil
}
n, err := stream.out.Write(stream.buf[0:stream.n])
if n < stream.n && err == nil {
err = io.ErrShortWrite
}
if err != nil {
if n > 0 && n < stream.n {
copy(stream.buf[0:stream.n-n], stream.buf[n:stream.n])
}
stream.n -= n
stream.Error = err
return err
}
stream.n = 0
return nil
}
func (stream *Stream) ensure(minimal int) {
available := stream.Available()
if available < minimal {
stream.growAtLeast(minimal)
}
}
func (stream *Stream) growAtLeast(minimal int) {
if stream.out != nil {
stream.Flush()
if stream.Available() >= minimal {
return
}
}
toGrow := len(stream.buf)
if toGrow < minimal {
toGrow = minimal
}
newBuf := make([]byte, len(stream.buf)+toGrow)
copy(newBuf, stream.Buffer())
stream.buf = newBuf
}
// WriteRaw write string out without quotes, just like []byte
func (stream *Stream) WriteRaw(s string) {
stream.ensure(len(s))
if stream.Error != nil {
return
}
n := copy(stream.buf[stream.n:], s)
stream.n += n
}
// WriteNil write null to stream
func (stream *Stream) WriteNil() {
stream.writeFourBytes('n', 'u', 'l', 'l')
}
// WriteTrue write true to stream
func (stream *Stream) WriteTrue() {
stream.writeFourBytes('t', 'r', 'u', 'e')
}
// WriteFalse write false to stream
func (stream *Stream) WriteFalse() {
stream.writeFiveBytes('f', 'a', 'l', 's', 'e')
}
// WriteBool write true or false into stream
func (stream *Stream) WriteBool(val bool) {
if val {
stream.WriteTrue()
} else {
stream.WriteFalse()
}
}
// WriteObjectStart write { with possible indention
func (stream *Stream) WriteObjectStart() {
stream.indention += stream.cfg.indentionStep
stream.writeByte('{')
stream.writeIndention(0)
}
// WriteObjectField write "field": with possible indention
func (stream *Stream) WriteObjectField(field string) {
stream.WriteString(field)
if stream.indention > 0 {
stream.writeTwoBytes(':', ' ')
} else {
stream.writeByte(':')
}
}
// WriteObjectEnd write } with possible indention
func (stream *Stream) WriteObjectEnd() {
stream.writeIndention(stream.cfg.indentionStep)
stream.indention -= stream.cfg.indentionStep
stream.writeByte('}')
}
// WriteEmptyObject write {}
func (stream *Stream) WriteEmptyObject() {
stream.writeByte('{')
stream.writeByte('}')
}
// WriteMore write , with possible indention
func (stream *Stream) WriteMore() {
stream.writeByte(',')
stream.writeIndention(0)
}
// WriteArrayStart write [ with possible indention
func (stream *Stream) WriteArrayStart() {
stream.indention += stream.cfg.indentionStep
stream.writeByte('[')
stream.writeIndention(0)
}
// WriteEmptyArray write []
func (stream *Stream) WriteEmptyArray() {
stream.writeTwoBytes('[', ']')
}
// WriteArrayEnd write ] with possible indention
func (stream *Stream) WriteArrayEnd() {
stream.writeIndention(stream.cfg.indentionStep)
stream.indention -= stream.cfg.indentionStep
stream.writeByte(']')
}
func (stream *Stream) writeIndention(delta int) {
if stream.indention == 0 {
return
}
stream.writeByte('\n')
toWrite := stream.indention - delta
stream.ensure(toWrite)
for i := 0; i < toWrite && stream.n < len(stream.buf); i++ {
stream.buf[stream.n] = ' '
stream.n++
}
}