Go Bufio Pack

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Go Bufio Pack

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 so Me help for textual I/O.

Bufio. Reader Fabric Body

// Reader implements buffering for an io.Reader object.type Reader struct {buf          []byterd           io.Reader // reader provided by the clientr, w         int       // buf read and write positionserr          errorlastByte     intlastRuneSize int}

All the way,

func NewReader(rd io.Reader) *Readerfunc NewReaderSize(rd io.Reader, size int) *Readerfunc (b *Reader) Buffered() intfunc (b *Reader) Discard(n int) (discarded int, err error)func (b *Reader) Peek(n int) ([]byte, error)func (b *Reader) Read(p []byte) (n int, err error)func (b *Reader) ReadByte() (byte, error)func (b *Reader) ReadBytes(delim byte) ([]byte, error)func (b *Reader) ReadLine() (line []byte, isPrefix bool, err error)func (b *Reader) ReadRune() (r rune, size int, err error)func (b *Reader) ReadSlice(delim byte) (line []byte, err error)func (b *Reader) ReadString(delim byte) (string, error)func (b *Reader) Reset(r io.Reader)func (b *Reader) UnreadByte() errorfunc (b *Reader) UnreadRune() errorfunc (b *Reader) WriteTo(w io.Writer) (n int64, err error)

Using the example,

Package Mainimport ("bytes" "Bufio" "FMT") func main () {b1: = []byte ("Hello world!") RD: = bytes. Newreader (B1) buf: = Bufio. Newreader (RD)//The default buffer size is 4096fmt. Printf ("1.the number of bytes that can is read from the buffer=%d\n", buf. Buffered ()) B2: = Make ([]byte, 5) buf. Read (B2) println (String (b2)) fmt. Printf ("2.the number of bytes that can is read from the buffer=%d\n", buf. Buffered ()) d, _: = buf. Discard (1) fmt. Printf ("3.the number of Discard bytes =%d\n", d) B3: = Make ([]byte, 5) buf. Read (B3) println (String (b3)) fmt. Printf ("4.the number of bytes that can is read from the buffer=%d\n", buf. Buffered ()) fmt. Println ("--------------") Rd2: = bytes. Newreader ([]byte ("Hello World")) Buf2: = Bufio. Newreader (RD2)//Peek Returns a slice of the cache that references the first n bytes of data in the cache,//the operation does not read the data, only references, and the referenced data is valid for the next read operation//. If the slice length is less than n, an error message is returned stating the reason. If n is greater than the total size of the cache, Errbufferfull is returned. B4, _: = Buf2. Peek (5) println (String (B4)) b4[0] = ' a ' b4[1] = ' a ' b4[2] = ' a ' b4[3] = ' a ' b4[4] = ' a ' FMT. Printf ("5.the number of bytes that can isRead from the current buffer=%d\n ", Buf2. Buffered ()) for {b, err: = Buf2. ReadByte () if err! = Nil {break}fmt. Print (string (b))//AAAAA World}}

Bufio. Writer Structural body

// 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.type Writer struct {err errorbuf []byten   intwr  io.Writer}

All the way,

func NewWriter(w io.Writer) *Writerfunc NewWriterSize(w io.Writer, size int) *Writerfunc (b *Writer) Available() intfunc (b *Writer) Buffered() intfunc (b *Writer) Flush() errorfunc (b *Writer) ReadFrom(r io.Reader) (n int64, err error)func (b *Writer) Reset(w io.Writer)func (b *Writer) Write(p []byte) (nn int, err error)func (b *Writer) WriteByte(c byte) errorfunc (b *Writer) WriteRune(r rune) (size int, err error)func (b *Writer) WriteString(s string) (int, error)

Method uses an example,

package mainimport ("bufio""os""fmt")func main() {buf := bufio.NewWriterSize(os.Stdout, 0)fmt.Println(buf.Available(), buf.Buffered())buf.WriteString("hello world")fmt.Println(buf.Available(), buf.Buffered())str := "我是中国人"for _, ele := range []rune(str) {buf.WriteRune(ele)}// 缓存后统一输出，避免终端频繁刷新，影响速度buf.Flush()}

Bufio. Scanner Structural body

Scanner provides a convenient interface for reading data such as//a file of newline-delimited lines of text. Successive calls to//the Scan method would step through the ' tokens ' of a file, skipping//the bytes between the tokens. The specification of a token is//defined by a split function of type splitfunc; The default split//function breaks the input into lines with line termination stripped. split//functions is defined in the this package for scanning a file into//lines, bytes, utf-8-encoded runes, and Space-deli mited words.  the//client may instead provide a custom split function.////scanning stops unrecoverably at EOF, the first I/O error, or A token too//large to fit in the buffer. When a scan is stops, the reader may have//advanced arbitrarily far past the last token. Programs that need more//control over error handling or large tokens, or must run sequential scans//on a reader, should Use Bufio. Reader Instead.//type Scanner struct {r io. Reader//The reader PROvided by the Client.split splitfunc//The function to split the tokens.maxtokensize int//Maximum size of a token;  Modified by Tests.token []byte//Last token returned by split.buf []byte//Buffer used as argument          to Split.start Int//First non-processed byte in buf.end int//end of the data in Buf.err Error//Sticky error.empties int//Count of successive empty tokens.scancalled bool//Scan ha s been called; Buffer is in use.done bool//Scan have finished.}

All the way,

func NewScanner(r io.Reader) *Scannerfunc (s *Scanner) Buffer(buf []byte, max int)func (s *Scanner) Bytes() []bytefunc (s *Scanner) Err() errorfunc (s *Scanner) Scan() boolfunc (s *Scanner) Split(split SplitFunc)func (s *Scanner) Text() string

Method uses an example,

package mainimport ("os""bufio""fmt")func main() {var path = "/Users/xinxingegeya/workspace-go/src/awesomeProject/bufio/temp.txt"file, _ := os.Open(path)scanner := bufio.NewScanner(file)// Split 用于设置“匹配函数”，这个函数必须在调用 Scan 前执行。scanner.Split(bufio.ScanLines)// Scan 开始一次扫描过程，如果匹配成功，可以通过 Bytes() 或 Text() 方法取出结果，// 如果遇到错误，则终止扫描，并返回 false。for scanner.Scan() {var record = scanner.Text()fmt.Println(record)}}

Bufio. Readerwriter Structural Body

// buffered input and output// ReadWriter stores pointers to a Reader and a Writer.// It implements io.ReadWriter.type ReadWriter struct {*Reader*Writer}

All the way,

func NewReadWriter(r *Reader, w *Writer) *ReadWriter

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