bufio

Documentation

Overview

Package bufio implements buffered I/O. It wraps an io.Reader or io.Writer object, creating another object (Reader or Writer) that also implements the interface but provides buffering and some help for textual I/O.

Index

• Variables
• type Reader
  • func NewReader(rd io.Reader) *Reader
  • func NewReaderSize(rd io.Reader, size int) *Reader
  • func (b *Reader) Buffered() int
  • func (b *Reader) Discard(n int) (discarded int, err error)
  • func (b *Reader) Peek(n int) ([]byte, error)
  • func (b *Reader) Pop(n int) ([]byte, error)
  • func (b *Reader) Read(p []byte) (n int, err error)
  • func (b *Reader) ReadByte() (c byte, err error)
  • func (b *Reader) ReadLine() (line []byte, isPrefix bool, err error)
  • func (b *Reader) ReadSlice(delim byte) (line []byte, err error)
  • func (b *Reader) Reset(r io.Reader)
  • func (b *Reader) ResetBuffer(r io.Reader, buf []byte)
• type Writer
  • func NewWriter(w io.Writer) *Writer
  • func NewWriterSize(w io.Writer, size int) *Writer
  • func (b *Writer) Available() int
  • func (b *Writer) Buffered() int
  • func (b *Writer) Flush() error
  • func (b *Writer) Peek(n int) ([]byte, error)
  • func (b *Writer) Reset(w io.Writer)
  • func (b *Writer) ResetBuffer(w io.Writer, buf []byte)
  • func (b *Writer) Write(p []byte) (nn int, err error)
  • func (b *Writer) WriteRaw(p []byte) (nn int, err error)
  • func (b *Writer) WriteString(s string) (int, error)

Variables

var (
	// ErrInvalidUnreadByte invalid use of UnreadByete
	ErrInvalidUnreadByte = errors.New("bufio: invalid use of UnreadByte")
	// ErrInvalidUnreadRune invalid use of UnreadRune
	ErrInvalidUnreadRune = errors.New("bufio: invalid use of UnreadRune")
	// ErrBufferFull buffer full
	ErrBufferFull = errors.New("bufio: buffer full")
	// ErrNegativeCount negative count
	ErrNegativeCount = errors.New("bufio: negative count")
)

Types

type Reader

type Reader struct {
	// contains filtered or unexported fields
}

Reader implements buffering for an io.Reader object.

func NewReader

func NewReader(rd io.Reader) *Reader

NewReader returns a new Reader whose buffer has the default size.

func NewReaderSize

func NewReaderSize(rd io.Reader, size int) *Reader

NewReaderSize returns a new Reader whose buffer has at least the specified size. If the argument io.Reader is already a Reader with large enough size, it returns the underlying Reader.

func (*Reader) Buffered

func (b *Reader) Buffered() int

Buffered returns the number of bytes that can be read from the current buffer.

func (*Reader) Discard

func (b *Reader) Discard(n int) (discarded int, err error)

Discard skips the next n bytes, returning the number of bytes discarded.

If Discard skips fewer than n bytes, it also returns an error. If 0 <= n <= b.Buffered(), Discard is guaranteed to succeed without reading from the underlying io.Reader.

func (*Reader) Peek

func (b *Reader) Peek(n int) ([]byte, error)

Peek returns the next n bytes without advancing the reader. The bytes stop being valid at the next read call. If Peek returns fewer than n bytes, it also returns an error explaining why the read is short. The error is ErrBufferFull if n is larger than b's buffer size.

func (*Reader) Pop

func (b *Reader) Pop(n int) ([]byte, error)

Pop returns the next n bytes with advancing the reader. The bytes stop being valid at the next read call. If Pop returns fewer than n bytes, it also returns an error explaining why the read is short. The error is ErrBufferFull if n is larger than b's buffer size.

func (*Reader) Read

func (b *Reader) Read(p []byte) (n int, err error)

Read reads data into p. It returns the number of bytes read into p. It calls Read at most once on the underlying Reader, hence n may be less than len(p). At EOF, the count will be zero and err will be io.EOF.

func (*Reader) ReadByte

func (b *Reader) ReadByte() (c byte, err error)

ReadByte reads and returns a single byte. If no byte is available, returns an error.

func (*Reader) ReadLine

func (b *Reader) ReadLine() (line []byte, isPrefix bool, err error)

ReadLine is a low-level line-reading primitive. Most callers should use ReadBytes('\n') or ReadString('\n') instead or use a Scanner.

ReadLine tries to return a single line, not including the end-of-line bytes. If the line was too long for the buffer then isPrefix is set and the beginning of the line is returned. The rest of the line will be returned from future calls. isPrefix will be false when returning the last fragment of the line. The returned buffer is only valid until the next call to ReadLine. ReadLine either returns a non-nil line or it returns an error, never both.

The text returned from ReadLine does not include the line end ("\r\n" or "\n"). No indication or error is given if the input ends without a final line end. Calling UnreadByte after ReadLine will always unread the last byte read (possibly a character belonging to the line end) even if that byte is not part of the line returned by ReadLine.

func (*Reader) ReadSlice

func (b *Reader) ReadSlice(delim byte) (line []byte, err error)

ReadSlice reads until the first occurrence of delim in the input, returning a slice pointing at the bytes in the buffer. The bytes stop being valid at the next read. If ReadSlice encounters an error before finding a delimiter, it returns all the data in the buffer and the error itself (often io.EOF). ReadSlice fails with error ErrBufferFull if the buffer fills without a delim. Because the data returned from ReadSlice will be overwritten by the next I/O operation, most clients should use ReadBytes or ReadString instead. ReadSlice returns err != nil if and only if line does not end in delim.

func (*Reader) Reset

func (b *Reader) Reset(r io.Reader)

Reset discards any buffered data, resets all state, and switches the buffered reader to read from r.

func (*Reader) ResetBuffer

func (b *Reader) ResetBuffer(r io.Reader, buf []byte)

ResetBuffer discards any buffered data, resets all state, and switches the buffered reader to read from r.

type Writer

type Writer struct {
	// contains filtered or unexported fields
}

Writer implements buffering for an io.Writer object. If an error occurs writing to a Writer, no more data will be accepted and all subsequent writes will return the error. After all data has been written, the client should call the Flush method to guarantee all data has been forwarded to the underlying io.Writer.

func NewWriter

func NewWriter(w io.Writer) *Writer

NewWriter returns a new Writer whose buffer has the default size.

func NewWriterSize

func NewWriterSize(w io.Writer, size int) *Writer

NewWriterSize returns a new Writer whose buffer has at least the specified size. If the argument io.Writer is already a Writer with large enough size, it returns the underlying Writer.

func (*Writer) Available

func (b *Writer) Available() int

Available returns how many bytes are unused in the buffer.

func (*Writer) Buffered

func (b *Writer) Buffered() int

Buffered returns the number of bytes that have been written into the current buffer.

func (*Writer) Flush

func (b *Writer) Flush() error

Flush writes any buffered data to the underlying io.Writer.

func (*Writer) Peek

func (b *Writer) Peek(n int) ([]byte, error)

Peek returns the next n bytes with advancing the writer. The bytes stop being used at the next write call. If Peek returns fewer than n bytes, it also returns an error explaining why the read is short. The error is ErrBufferFull if n is larger than b's buffer size.

func (*Writer) Reset

func (b *Writer) Reset(w io.Writer)

Reset discards any unflushed buffered data, clears any error, and resets b to write its output to w.

func (*Writer) ResetBuffer

func (b *Writer) ResetBuffer(w io.Writer, buf []byte)

ResetBuffer discards any unflushed buffered data, clears any error, and resets b to write its output to w.

func (*Writer) Write

func (b *Writer) Write(p []byte) (nn int, err error)

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 (*Writer) WriteRaw

func (b *Writer) WriteRaw(p []byte) (nn int, err error)

WriteRaw writes the contents of p into the raw io.Writer without buffer. It returns the number of bytes written. If nn < len(p), it also returns an error explaining why the write is short.

func (*Writer) WriteString

func (b *Writer) WriteString(s string) (int, error)

WriteString writes a string. It returns the number of bytes written. If the count is less than len(s), it also returns an error explaining why the write is short.