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