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[/] [openrisc/] [trunk/] [gnu-dev/] [or1k-gcc/] [libgo/] [go/] [bufio/] [bufio.go] - Blame information for rev 774

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// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
 
// 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.
package bufio
 
import (
        "bytes"
        "errors"
        "io"
        "unicode/utf8"
)
 
const (
        defaultBufSize = 4096
)
 
var (
        ErrInvalidUnreadByte = errors.New("bufio: invalid use of UnreadByte")
        ErrInvalidUnreadRune = errors.New("bufio: invalid use of UnreadRune")
        ErrBufferFull        = errors.New("bufio: buffer full")
        ErrNegativeCount     = errors.New("bufio: negative count")
        errInternal          = errors.New("bufio: internal error")
)
 
// Buffered input.
 
// Reader implements buffering for an io.Reader object.
type Reader struct {
        buf          []byte
        rd           io.Reader
        r, w         int
        err          error
        lastByte     int
        lastRuneSize int
}
 
const minReadBufferSize = 16
 
// 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 NewReaderSize(rd io.Reader, size int) *Reader {
        // Is it already a Reader?
        b, ok := rd.(*Reader)
        if ok && len(b.buf) >= size {
                return b
        }
        if size < minReadBufferSize {
                size = minReadBufferSize
        }
        return &Reader{
                buf:          make([]byte, size),
                rd:           rd,
                lastByte:     -1,
                lastRuneSize: -1,
        }
}
 
// NewReader returns a new Reader whose buffer has the default size.
func NewReader(rd io.Reader) *Reader {
        return NewReaderSize(rd, defaultBufSize)
}
 
// fill reads a new chunk into the buffer.
func (b *Reader) fill() {
        // Slide existing data to beginning.
        if b.r > 0 {
                copy(b.buf, b.buf[b.r:b.w])
                b.w -= b.r
                b.r = 0
        }
 
        // Read new data.
        n, e := b.rd.Read(b.buf[b.w:])
        b.w += n
        if e != nil {
                b.err = e
        }
}
 
func (b *Reader) readErr() error {
        err := b.err
        b.err = nil
        return err
}
 
// 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 (b *Reader) Peek(n int) ([]byte, error) {
        if n < 0 {
                return nil, ErrNegativeCount
        }
        if n > len(b.buf) {
                return nil, ErrBufferFull
        }
        for b.w-b.r < n && b.err == nil {
                b.fill()
        }
        m := b.w - b.r
        if m > n {
                m = n
        }
        err := b.readErr()
        if m < n && err == nil {
                err = ErrBufferFull
        }
        return b.buf[b.r : b.r+m], err
}
 
// 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 (b *Reader) Read(p []byte) (n int, err error) {
        n = len(p)
        if n == 0 {
                return 0, b.readErr()
        }
        if b.w == b.r {
                if b.err != nil {
                        return 0, b.readErr()
                }
                if len(p) >= len(b.buf) {
                        // Large read, empty buffer.
                        // Read directly into p to avoid copy.
                        n, b.err = b.rd.Read(p)
                        if n > 0 {
                                b.lastByte = int(p[n-1])
                                b.lastRuneSize = -1
                        }
                        return n, b.readErr()
                }
                b.fill()
                if b.w == b.r {
                        return 0, b.readErr()
                }
        }
 
        if n > b.w-b.r {
                n = b.w - b.r
        }
        copy(p[0:n], b.buf[b.r:])
        b.r += n
        b.lastByte = int(b.buf[b.r-1])
        b.lastRuneSize = -1
        return n, nil
}
 
// ReadByte reads and returns a single byte.
// If no byte is available, returns an error.
func (b *Reader) ReadByte() (c byte, err error) {
        b.lastRuneSize = -1
        for b.w == b.r {
                if b.err != nil {
                        return 0, b.readErr()
                }
                b.fill()
        }
        c = b.buf[b.r]
        b.r++
        b.lastByte = int(c)
        return c, nil
}
 
// UnreadByte unreads the last byte.  Only the most recently read byte can be unread.
func (b *Reader) UnreadByte() error {
        b.lastRuneSize = -1
        if b.r == b.w && b.lastByte >= 0 {
                b.w = 1
                b.r = 0
                b.buf[0] = byte(b.lastByte)
                b.lastByte = -1
                return nil
        }
        if b.r <= 0 {
                return ErrInvalidUnreadByte
        }
        b.r--
        b.lastByte = -1
        return nil
}
 
// ReadRune reads a single UTF-8 encoded Unicode character and returns the
// rune and its size in bytes. If the encoded rune is invalid, it consumes one byte
// and returns unicode.ReplacementChar (U+FFFD) with a size of 1.
func (b *Reader) ReadRune() (r rune, size int, err error) {
        for b.r+utf8.UTFMax > b.w && !utf8.FullRune(b.buf[b.r:b.w]) && b.err == nil {
                b.fill()
        }
        b.lastRuneSize = -1
        if b.r == b.w {
                return 0, 0, b.readErr()
        }
        r, size = rune(b.buf[b.r]), 1
        if r >= 0x80 {
                r, size = utf8.DecodeRune(b.buf[b.r:b.w])
        }
        b.r += size
        b.lastByte = int(b.buf[b.r-1])
        b.lastRuneSize = size
        return r, size, nil
}
 
// UnreadRune unreads the last rune.  If the most recent read operation on
// the buffer was not a ReadRune, UnreadRune returns an error.  (In this
// regard it is stricter than UnreadByte, which will unread the last byte
// from any read operation.)
func (b *Reader) UnreadRune() error {
        if b.lastRuneSize < 0 || b.r == 0 {
                return ErrInvalidUnreadRune
        }
        b.r -= b.lastRuneSize
        b.lastByte = -1
        b.lastRuneSize = -1
        return nil
}
 
// Buffered returns the number of bytes that can be read from the current buffer.
func (b *Reader) Buffered() int { return b.w - b.r }
 
// 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 call.
// 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 (b *Reader) ReadSlice(delim byte) (line []byte, err error) {
        // Look in buffer.
        if i := bytes.IndexByte(b.buf[b.r:b.w], delim); i >= 0 {
                line1 := b.buf[b.r : b.r+i+1]
                b.r += i + 1
                return line1, nil
        }
 
        // Read more into buffer, until buffer fills or we find delim.
        for {
                if b.err != nil {
                        line := b.buf[b.r:b.w]
                        b.r = b.w
                        return line, b.readErr()
                }
 
                n := b.Buffered()
                b.fill()
 
                // Search new part of buffer
                if i := bytes.IndexByte(b.buf[n:b.w], delim); i >= 0 {
                        line := b.buf[0 : n+i+1]
                        b.r = n + i + 1
                        return line, nil
                }
 
                // Buffer is full?
                if b.Buffered() >= len(b.buf) {
                        b.r = b.w
                        return b.buf, ErrBufferFull
                }
        }
        panic("not reached")
}
 
// 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.
func (b *Reader) ReadLine() (line []byte, isPrefix bool, err error) {
        line, err = b.ReadSlice('\n')
        if err == ErrBufferFull {
                // Handle the case where "\r\n" straddles the buffer.
                if len(line) > 0 && line[len(line)-1] == '\r' {
                        // Put the '\r' back on buf and drop it from line.
                        // Let the next call to ReadLine check for "\r\n".
                        if b.r == 0 {
                                // should be unreachable
                                panic("bufio: tried to rewind past start of buffer")
                        }
                        b.r--
                        line = line[:len(line)-1]
                }
                return line, true, nil
        }
 
        if len(line) == 0 {
                if err != nil {
                        line = nil
                }
                return
        }
        err = nil
 
        if line[len(line)-1] == '\n' {
                drop := 1
                if len(line) > 1 && line[len(line)-2] == '\r' {
                        drop = 2
                }
                line = line[:len(line)-drop]
        }
        return
}
 
// ReadBytes reads until the first occurrence of delim in the input,
// returning a slice containing the data up to and including the delimiter.
// If ReadBytes encounters an error before finding a delimiter,
// it returns the data read before the error and the error itself (often io.EOF).
// ReadBytes returns err != nil if and only if the returned data does not end in
// delim.
func (b *Reader) ReadBytes(delim byte) (line []byte, err error) {
        // Use ReadSlice to look for array,
        // accumulating full buffers.
        var frag []byte
        var full [][]byte
        err = nil
 
        for {
                var e error
                frag, e = b.ReadSlice(delim)
                if e == nil { // got final fragment
                        break
                }
                if e != ErrBufferFull { // unexpected error
                        err = e
                        break
                }
 
                // Make a copy of the buffer.
                buf := make([]byte, len(frag))
                copy(buf, frag)
                full = append(full, buf)
        }
 
        // Allocate new buffer to hold the full pieces and the fragment.
        n := 0
        for i := range full {
                n += len(full[i])
        }
        n += len(frag)
 
        // Copy full pieces and fragment in.
        buf := make([]byte, n)
        n = 0
        for i := range full {
                n += copy(buf[n:], full[i])
        }
        copy(buf[n:], frag)
        return buf, err
}
 
// ReadString reads until the first occurrence of delim in the input,
// returning a string containing the data up to and including the delimiter.
// If ReadString encounters an error before finding a delimiter,
// it returns the data read before the error and the error itself (often io.EOF).
// ReadString returns err != nil if and only if the returned data does not end in
// delim.
func (b *Reader) ReadString(delim byte) (line string, err error) {
        bytes, e := b.ReadBytes(delim)
        return string(bytes), e
}
 
// buffered output
 
// 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.
type Writer struct {
        err error
        buf []byte
        n   int
        wr  io.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 NewWriterSize(wr io.Writer, size int) *Writer {
        // Is it already a Writer?
        b, ok := wr.(*Writer)
        if ok && len(b.buf) >= size {
                return b
        }
        if size <= 0 {
                size = defaultBufSize
        }
        b = new(Writer)
        b.buf = make([]byte, size)
        b.wr = wr
        return b
}
 
// NewWriter returns a new Writer whose buffer has the default size.
func NewWriter(wr io.Writer) *Writer {
        return NewWriterSize(wr, defaultBufSize)
}
 
// Flush writes any buffered data to the underlying io.Writer.
func (b *Writer) Flush() error {
        if b.err != nil {
                return b.err
        }
        if b.n == 0 {
                return nil
        }
        n, e := b.wr.Write(b.buf[0:b.n])
        if n < b.n && e == nil {
                e = io.ErrShortWrite
        }
        if e != nil {
                if n > 0 && n < b.n {
                        copy(b.buf[0:b.n-n], b.buf[n:b.n])
                }
                b.n -= n
                b.err = e
                return e
        }
        b.n = 0
        return nil
}
 
// Available returns how many bytes are unused in the buffer.
func (b *Writer) Available() int { return len(b.buf) - b.n }
 
// Buffered returns the number of bytes that have been written into the current buffer.
func (b *Writer) Buffered() int { return b.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 (b *Writer) Write(p []byte) (nn int, err error) {
        for len(p) > b.Available() && b.err == nil {
                var n int
                if b.Buffered() == 0 {
                        // Large write, empty buffer.
                        // Write directly from p to avoid copy.
                        n, b.err = b.wr.Write(p)
                } else {
                        n = copy(b.buf[b.n:], p)
                        b.n += n
                        b.Flush()
                }
                nn += n
                p = p[n:]
        }
        if b.err != nil {
                return nn, b.err
        }
        n := copy(b.buf[b.n:], p)
        b.n += n
        nn += n
        return nn, nil
}
 
// WriteByte writes a single byte.
func (b *Writer) WriteByte(c byte) error {
        if b.err != nil {
                return b.err
        }
        if b.Available() <= 0 && b.Flush() != nil {
                return b.err
        }
        b.buf[b.n] = c
        b.n++
        return nil
}
 
// WriteRune writes a single Unicode code point, returning
// the number of bytes written and any error.
func (b *Writer) WriteRune(r rune) (size int, err error) {
        if r < utf8.RuneSelf {
                err = b.WriteByte(byte(r))
                if err != nil {
                        return 0, err
                }
                return 1, nil
        }
        if b.err != nil {
                return 0, b.err
        }
        n := b.Available()
        if n < utf8.UTFMax {
                if b.Flush(); b.err != nil {
                        return 0, b.err
                }
                n = b.Available()
                if n < utf8.UTFMax {
                        // Can only happen if buffer is silly small.
                        return b.WriteString(string(r))
                }
        }
        size = utf8.EncodeRune(b.buf[b.n:], r)
        b.n += size
        return size, nil
}
 
// 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.
func (b *Writer) WriteString(s string) (int, error) {
        nn := 0
        for len(s) > b.Available() && b.err == nil {
                n := copy(b.buf[b.n:], s)
                b.n += n
                nn += n
                s = s[n:]
                b.Flush()
        }
        if b.err != nil {
                return nn, b.err
        }
        n := copy(b.buf[b.n:], s)
        b.n += n
        nn += n
        return nn, nil
}
 
// buffered input and output
 
// ReadWriter stores pointers to a Reader and a Writer.
// It implements io.ReadWriter.
type ReadWriter struct {
        *Reader
        *Writer
}
 
// NewReadWriter allocates a new ReadWriter that dispatches to r and w.
func NewReadWriter(r *Reader, w *Writer) *ReadWriter {
        return &ReadWriter{r, w}
}

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[/] [openrisc/] [trunk/] [gnu-dev/] [or1k-gcc/] [libgo/] [go/] [bufio/] [bufio.go] - Blame information for rev 774

Line No.	Rev	Author	Line
1	747	jeremybenn	`// Copyright 2009 The Go Authors. All rights reserved.`
2			`// Use of this source code is governed by a BSD-style`
3			`// license that can be found in the LICENSE file.`
4
5			`// Package bufio implements buffered I/O. It wraps an io.Reader or io.Writer`
6			`// object, creating another object (Reader or Writer) that also implements`
7			`// the interface but provides buffering and some help for textual I/O.`
8			`package bufio`
9
10			`import (`
11			`"bytes"`
12			`"errors"`
13			`"io"`
14			`"unicode/utf8"`
15			`)`
16
17			`const (`
18			`defaultBufSize = 4096`
19			`)`
20
21			`var (`
22			`ErrInvalidUnreadByte = errors.New("bufio: invalid use of UnreadByte")`
23			`ErrInvalidUnreadRune = errors.New("bufio: invalid use of UnreadRune")`
24			`ErrBufferFull = errors.New("bufio: buffer full")`
25			`ErrNegativeCount = errors.New("bufio: negative count")`
26			`errInternal = errors.New("bufio: internal error")`
27			`)`
28
29			`// Buffered input.`
30
31			`// Reader implements buffering for an io.Reader object.`
32			`type Reader struct {`
33			`buf []byte`
34			`rd io.Reader`
35			`r, w int`
36			`err error`
37			`lastByte int`
38			`lastRuneSize int`
39			`}`
40
41			`const minReadBufferSize = 16`
42
43			`// NewReaderSize returns a new Reader whose buffer has at least the specified`
44			`// size. If the argument io.Reader is already a Reader with large enough`
45			`// size, it returns the underlying Reader.`
46			`func NewReaderSize(rd io.Reader, size int) *Reader {`
47			`// Is it already a Reader?`
48			`b, ok := rd.(*Reader)`
49			`if ok && len(b.buf) >= size {`
50			`return b`
51			`}`
52			`if size < minReadBufferSize {`
53			`size = minReadBufferSize`
54			`}`
55			`return &Reader{`
56			`buf: make([]byte, size),`
57			`rd: rd,`
58			`lastByte: -1,`
59			`lastRuneSize: -1,`
60			`}`
61			`}`
62
63			`// NewReader returns a new Reader whose buffer has the default size.`
64			`func NewReader(rd io.Reader) *Reader {`
65			`return NewReaderSize(rd, defaultBufSize)`
66			`}`
67
68			`// fill reads a new chunk into the buffer.`
69			`func (b *Reader) fill() {`
70			`// Slide existing data to beginning.`
71			`if b.r > 0 {`
72			`copy(b.buf, b.buf[b.r:b.w])`
73			`b.w -= b.r`
74			`b.r = 0`
75			`}`
76
77			`// Read new data.`
78			`n, e := b.rd.Read(b.buf[b.w:])`
79			`b.w += n`
80			`if e != nil {`
81			`b.err = e`
82			`}`
83			`}`
84
85			`func (b *Reader) readErr() error {`
86			`err := b.err`
87			`b.err = nil`
88			`return err`
89			`}`
90
91			`// Peek returns the next n bytes without advancing the reader. The bytes stop`
92			`// being valid at the next read call. If Peek returns fewer than n bytes, it`
93			`// also returns an error explaining why the read is short. The error is`
94			`// ErrBufferFull if n is larger than b's buffer size.`
95			`func (b *Reader) Peek(n int) ([]byte, error) {`
96			`if n < 0 {`
97			`return nil, ErrNegativeCount`
98			`}`
99			`if n > len(b.buf) {`
100			`return nil, ErrBufferFull`
101			`}`
102			`for b.w-b.r < n && b.err == nil {`
103			`b.fill()`
104			`}`
105			`m := b.w - b.r`
106			`if m > n {`
107			`m = n`
108			`}`
109			`err := b.readErr()`
110			`if m < n && err == nil {`
111			`err = ErrBufferFull`
112			`}`
113			`return b.buf[b.r : b.r+m], err`
114			`}`
115
116			`// Read reads data into p.`
117			`// It returns the number of bytes read into p.`
118			`// It calls Read at most once on the underlying Reader,`
119			`// hence n may be less than len(p).`
120			`// At EOF, the count will be zero and err will be io.EOF.`
121			`func (b *Reader) Read(p []byte) (n int, err error) {`
122			`n = len(p)`
123			`if n == 0 {`
124			`return 0, b.readErr()`
125			`}`
126			`if b.w == b.r {`
127			`if b.err != nil {`
128			`return 0, b.readErr()`
129			`}`
130			`if len(p) >= len(b.buf) {`
131			`// Large read, empty buffer.`
132			`// Read directly into p to avoid copy.`
133			`n, b.err = b.rd.Read(p)`
134			`if n > 0 {`
135			`b.lastByte = int(p[n-1])`
136			`b.lastRuneSize = -1`
137			`}`
138			`return n, b.readErr()`
139			`}`
140			`b.fill()`
141			`if b.w == b.r {`
142			`return 0, b.readErr()`
143			`}`
144			`}`
145
146			`if n > b.w-b.r {`
147			`n = b.w - b.r`
148			`}`
149			`copy(p[0:n], b.buf[b.r:])`
150			`b.r += n`
151			`b.lastByte = int(b.buf[b.r-1])`
152			`b.lastRuneSize = -1`
153			`return n, nil`
154			`}`
155
156			`// ReadByte reads and returns a single byte.`
157			`// If no byte is available, returns an error.`
158			`func (b *Reader) ReadByte() (c byte, err error) {`
159			`b.lastRuneSize = -1`
160			`for b.w == b.r {`
161			`if b.err != nil {`
162			`return 0, b.readErr()`
163			`}`
164			`b.fill()`
165			`}`
166			`c = b.buf[b.r]`
167			`b.r++`
168			`b.lastByte = int(c)`
169			`return c, nil`
170			`}`
171
172			`// UnreadByte unreads the last byte. Only the most recently read byte can be unread.`
173			`func (b *Reader) UnreadByte() error {`
174			`b.lastRuneSize = -1`
175			`if b.r == b.w && b.lastByte >= 0 {`
176			`b.w = 1`
177			`b.r = 0`
178			`b.buf[0] = byte(b.lastByte)`
179			`b.lastByte = -1`
180			`return nil`
181			`}`
182			`if b.r <= 0 {`
183			`return ErrInvalidUnreadByte`
184			`}`
185			`b.r--`
186			`b.lastByte = -1`
187			`return nil`
188			`}`
189
190			`// ReadRune reads a single UTF-8 encoded Unicode character and returns the`
191			`// rune and its size in bytes. If the encoded rune is invalid, it consumes one byte`
192			`// and returns unicode.ReplacementChar (U+FFFD) with a size of 1.`
193			`func (b *Reader) ReadRune() (r rune, size int, err error) {`
194			`for b.r+utf8.UTFMax > b.w && !utf8.FullRune(b.buf[b.r:b.w]) && b.err == nil {`
195			`b.fill()`
196			`}`
197			`b.lastRuneSize = -1`
198			`if b.r == b.w {`
199			`return 0, 0, b.readErr()`
200			`}`
201			`r, size = rune(b.buf[b.r]), 1`
202			`if r >= 0x80 {`
203			`r, size = utf8.DecodeRune(b.buf[b.r:b.w])`
204			`}`
205			`b.r += size`
206			`b.lastByte = int(b.buf[b.r-1])`
207			`b.lastRuneSize = size`
208			`return r, size, nil`
209			`}`
210
211			`// UnreadRune unreads the last rune. If the most recent read operation on`
212			`// the buffer was not a ReadRune, UnreadRune returns an error. (In this`
213			`// regard it is stricter than UnreadByte, which will unread the last byte`
214			`// from any read operation.)`
215			`func (b *Reader) UnreadRune() error {`
216			`if b.lastRuneSize < 0 \|\| b.r == 0 {`
217			`return ErrInvalidUnreadRune`
218			`}`
219			`b.r -= b.lastRuneSize`
220			`b.lastByte = -1`
221			`b.lastRuneSize = -1`
222			`return nil`
223			`}`
224
225			`// Buffered returns the number of bytes that can be read from the current buffer.`
226			`func (b *Reader) Buffered() int { return b.w - b.r }`
227
228			`// ReadSlice reads until the first occurrence of delim in the input,`
229			`// returning a slice pointing at the bytes in the buffer.`
230			`// The bytes stop being valid at the next read call.`
231			`// If ReadSlice encounters an error before finding a delimiter,`
232			`// it returns all the data in the buffer and the error itself (often io.EOF).`
233			`// ReadSlice fails with error ErrBufferFull if the buffer fills without a delim.`
234			`// Because the data returned from ReadSlice will be overwritten`
235			`// by the next I/O operation, most clients should use`
236			`// ReadBytes or ReadString instead.`
237			`// ReadSlice returns err != nil if and only if line does not end in delim.`
238			`func (b *Reader) ReadSlice(delim byte) (line []byte, err error) {`
239			`// Look in buffer.`
240			`if i := bytes.IndexByte(b.buf[b.r:b.w], delim); i >= 0 {`
241			`line1 := b.buf[b.r : b.r+i+1]`
242			`b.r += i + 1`
243			`return line1, nil`
244			`}`
245
246			`// Read more into buffer, until buffer fills or we find delim.`
247			`for {`
248			`if b.err != nil {`
249			`line := b.buf[b.r:b.w]`
250			`b.r = b.w`
251			`return line, b.readErr()`
252			`}`
253
254			`n := b.Buffered()`
255			`b.fill()`
256
257			`// Search new part of buffer`
258			`if i := bytes.IndexByte(b.buf[n:b.w], delim); i >= 0 {`
259			`line := b.buf[0 : n+i+1]`
260			`b.r = n + i + 1`
261			`return line, nil`
262			`}`
263
264			`// Buffer is full?`
265			`if b.Buffered() >= len(b.buf) {`
266			`b.r = b.w`
267			`return b.buf, ErrBufferFull`
268			`}`
269			`}`
270			`panic("not reached")`
271			`}`
272
273			`// ReadLine tries to return a single line, not including the end-of-line bytes.`
274			`// If the line was too long for the buffer then isPrefix is set and the`
275			`// beginning of the line is returned. The rest of the line will be returned`
276			`// from future calls. isPrefix will be false when returning the last fragment`
277			`// of the line. The returned buffer is only valid until the next call to`
278			`// ReadLine. ReadLine either returns a non-nil line or it returns an error,`
279			`// never both.`
280			`func (b *Reader) ReadLine() (line []byte, isPrefix bool, err error) {`
281			`line, err = b.ReadSlice('\n')`
282			`if err == ErrBufferFull {`
283			`// Handle the case where "\r\n" straddles the buffer.`
284			`if len(line) > 0 && line[len(line)-1] == '\r' {`
285			`// Put the '\r' back on buf and drop it from line.`
286			`// Let the next call to ReadLine check for "\r\n".`
287			`if b.r == 0 {`
288			`// should be unreachable`
289			`panic("bufio: tried to rewind past start of buffer")`
290			`}`
291			`b.r--`
292			`line = line[:len(line)-1]`
293			`}`
294			`return line, true, nil`
295			`}`
296
297			`if len(line) == 0 {`
298			`if err != nil {`
299			`line = nil`
300			`}`
301			`return`
302			`}`
303			`err = nil`
304
305			`if line[len(line)-1] == '\n' {`
306			`drop := 1`
307			`if len(line) > 1 && line[len(line)-2] == '\r' {`
308			`drop = 2`
309			`}`
310			`line = line[:len(line)-drop]`
311			`}`
312			`return`
313			`}`
314
315			`// ReadBytes reads until the first occurrence of delim in the input,`
316			`// returning a slice containing the data up to and including the delimiter.`
317			`// If ReadBytes encounters an error before finding a delimiter,`
318			`// it returns the data read before the error and the error itself (often io.EOF).`
319			`// ReadBytes returns err != nil if and only if the returned data does not end in`
320			`// delim.`
321			`func (b *Reader) ReadBytes(delim byte) (line []byte, err error) {`
322			`// Use ReadSlice to look for array,`
323			`// accumulating full buffers.`
324			`var frag []byte`
325			`var full [][]byte`
326			`err = nil`
327
328			`for {`
329			`var e error`
330			`frag, e = b.ReadSlice(delim)`
331			`if e == nil { // got final fragment`
332			`break`
333			`}`
334			`if e != ErrBufferFull { // unexpected error`
335			`err = e`
336			`break`
337			`}`
338
339			`// Make a copy of the buffer.`
340			`buf := make([]byte, len(frag))`
341			`copy(buf, frag)`
342			`full = append(full, buf)`
343			`}`
344
345			`// Allocate new buffer to hold the full pieces and the fragment.`
346			`n := 0`
347			`for i := range full {`
348			`n += len(full[i])`
349			`}`
350			`n += len(frag)`
351
352			`// Copy full pieces and fragment in.`
353			`buf := make([]byte, n)`
354			`n = 0`
355			`for i := range full {`
356			`n += copy(buf[n:], full[i])`
357			`}`
358			`copy(buf[n:], frag)`
359			`return buf, err`
360			`}`
361
362			`// ReadString reads until the first occurrence of delim in the input,`
363			`// returning a string containing the data up to and including the delimiter.`
364			`// If ReadString encounters an error before finding a delimiter,`
365			`// it returns the data read before the error and the error itself (often io.EOF).`
366			`// ReadString returns err != nil if and only if the returned data does not end in`
367			`// delim.`
368			`func (b *Reader) ReadString(delim byte) (line string, err error) {`
369			`bytes, e := b.ReadBytes(delim)`
370			`return string(bytes), e`
371			`}`
372
373			`// buffered output`
374
375			`// Writer implements buffering for an io.Writer object.`
376			`// If an error occurs writing to a Writer, no more data will be`
377			`// accepted and all subsequent writes will return the error.`
378			`type Writer struct {`
379			`err error`
380			`buf []byte`
381			`n int`
382			`wr io.Writer`
383			`}`
384
385			`// NewWriterSize returns a new Writer whose buffer has at least the specified`
386			`// size. If the argument io.Writer is already a Writer with large enough`
387			`// size, it returns the underlying Writer.`
388			`func NewWriterSize(wr io.Writer, size int) *Writer {`
389			`// Is it already a Writer?`
390			`b, ok := wr.(*Writer)`
391			`if ok && len(b.buf) >= size {`
392			`return b`
393			`}`
394			`if size <= 0 {`
395			`size = defaultBufSize`
396			`}`
397			`b = new(Writer)`
398			`b.buf = make([]byte, size)`
399			`b.wr = wr`
400			`return b`
401			`}`
402
403			`// NewWriter returns a new Writer whose buffer has the default size.`
404			`func NewWriter(wr io.Writer) *Writer {`
405			`return NewWriterSize(wr, defaultBufSize)`
406			`}`
407
408			`// Flush writes any buffered data to the underlying io.Writer.`
409			`func (b *Writer) Flush() error {`
410			`if b.err != nil {`
411			`return b.err`
412			`}`
413			`if b.n == 0 {`
414			`return nil`
415			`}`
416			`n, e := b.wr.Write(b.buf[0:b.n])`
417			`if n < b.n && e == nil {`
418			`e = io.ErrShortWrite`
419			`}`
420			`if e != nil {`
421			`if n > 0 && n < b.n {`
422			`copy(b.buf[0:b.n-n], b.buf[n:b.n])`
423			`}`
424			`b.n -= n`
425			`b.err = e`
426			`return e`
427			`}`
428			`b.n = 0`
429			`return nil`
430			`}`
431
432			`// Available returns how many bytes are unused in the buffer.`
433			`func (b *Writer) Available() int { return len(b.buf) - b.n }`
434
435			`// Buffered returns the number of bytes that have been written into the current buffer.`
436			`func (b *Writer) Buffered() int { return b.n }`
437
438			`// Write writes the contents of p into the buffer.`
439			`// It returns the number of bytes written.`
440			`// If nn < len(p), it also returns an error explaining`
441			`// why the write is short.`
442			`func (b *Writer) Write(p []byte) (nn int, err error) {`
443			`for len(p) > b.Available() && b.err == nil {`
444			`var n int`
445			`if b.Buffered() == 0 {`
446			`// Large write, empty buffer.`
447			`// Write directly from p to avoid copy.`
448			`n, b.err = b.wr.Write(p)`
449			`} else {`
450			`n = copy(b.buf[b.n:], p)`
451			`b.n += n`
452			`b.Flush()`
453			`}`
454			`nn += n`
455			`p = p[n:]`
456			`}`
457			`if b.err != nil {`
458			`return nn, b.err`
459			`}`
460			`n := copy(b.buf[b.n:], p)`
461			`b.n += n`
462			`nn += n`
463			`return nn, nil`
464			`}`
465
466			`// WriteByte writes a single byte.`
467			`func (b *Writer) WriteByte(c byte) error {`
468			`if b.err != nil {`
469			`return b.err`
470			`}`
471			`if b.Available() <= 0 && b.Flush() != nil {`
472			`return b.err`
473			`}`
474			`b.buf[b.n] = c`
475			`b.n++`
476			`return nil`
477			`}`
478
479			`// WriteRune writes a single Unicode code point, returning`
480			`// the number of bytes written and any error.`
481			`func (b *Writer) WriteRune(r rune) (size int, err error) {`
482			`if r < utf8.RuneSelf {`
483			`err = b.WriteByte(byte(r))`
484			`if err != nil {`
485			`return 0, err`
486			`}`
487			`return 1, nil`
488			`}`
489			`if b.err != nil {`
490			`return 0, b.err`
491			`}`
492			`n := b.Available()`
493			`if n < utf8.UTFMax {`
494			`if b.Flush(); b.err != nil {`
495			`return 0, b.err`
496			`}`
497			`n = b.Available()`
498			`if n < utf8.UTFMax {`
499			`// Can only happen if buffer is silly small.`
500			`return b.WriteString(string(r))`
501			`}`
502			`}`
503			`size = utf8.EncodeRune(b.buf[b.n:], r)`
504			`b.n += size`
505			`return size, nil`
506			`}`
507
508			`// WriteString writes a string.`
509			`// It returns the number of bytes written.`
510			`// If the count is less than len(s), it also returns an error explaining`
511			`// why the write is short.`
512			`func (b *Writer) WriteString(s string) (int, error) {`
513			`nn := 0`
514			`for len(s) > b.Available() && b.err == nil {`
515			`n := copy(b.buf[b.n:], s)`
516			`b.n += n`
517			`nn += n`
518			`s = s[n:]`
519			`b.Flush()`
520			`}`
521			`if b.err != nil {`
522			`return nn, b.err`
523			`}`
524			`n := copy(b.buf[b.n:], s)`
525			`b.n += n`
526			`nn += n`
527			`return nn, nil`
528			`}`
529
530			`// buffered input and output`
531
532			`// ReadWriter stores pointers to a Reader and a Writer.`
533			`// It implements io.ReadWriter.`
534			`type ReadWriter struct {`
535			`*Reader`
536			`*Writer`
537			`}`
538
539			`// NewReadWriter allocates a new ReadWriter that dispatches to r and w.`
540			`func NewReadWriter(r Reader, w Writer) *ReadWriter {`
541			`return &ReadWriter{r, w}`
542			`}`