diff options
Diffstat (limited to 'Godeps/_workspace/src/gopkg.in/bufio.v1/bufio.go')
| -rw-r--r-- | Godeps/_workspace/src/gopkg.in/bufio.v1/bufio.go | 728 |
1 files changed, 728 insertions, 0 deletions
diff --git a/Godeps/_workspace/src/gopkg.in/bufio.v1/bufio.go b/Godeps/_workspace/src/gopkg.in/bufio.v1/bufio.go new file mode 100644 index 000000000..8f5cdc084 --- /dev/null +++ b/Godeps/_workspace/src/gopkg.in/bufio.v1/bufio.go @@ -0,0 +1,728 @@ +// 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") +) + +// 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 +const maxConsecutiveEmptyReads = 100 + +// 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 + } + r := new(Reader) + r.reset(make([]byte, size), rd) + return r +} + +// NewReader returns a new Reader whose buffer has the default size. +func NewReader(rd io.Reader) *Reader { + return NewReaderSize(rd, defaultBufSize) +} + +// Reset discards any buffered data, resets all state, and switches +// the buffered reader to read from r. +func (b *Reader) Reset(r io.Reader) { + b.reset(b.buf, r) +} + +func (b *Reader) reset(buf []byte, r io.Reader) { + *b = Reader{ + buf: buf, + rd: r, + lastByte: -1, + lastRuneSize: -1, + } +} + +var errNegativeRead = errors.New("bufio: reader returned negative count from Read") + +// 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 + } + + if b.w >= len(b.buf) { + panic("bufio: tried to fill full buffer") + } + + // Read new data: try a limited number of times. + for i := maxConsecutiveEmptyReads; i > 0; i-- { + n, err := b.rd.Read(b.buf[b.w:]) + if n < 0 { + panic(errNegativeRead) + } + b.w += n + if err != nil { + b.err = err + return + } + if n > 0 { + return + } + } + b.err = io.ErrNoProgress +} + +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 + } + // 0 <= n <= len(b.buf) + for b.w-b.r < n && b.err == nil { + b.fill() // b.w-b.r < len(b.buf) => buffer is not full + } + m := b.w - b.r + if m > n { + m = n + } + var err error + if m < n { + err = b.readErr() + if 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.r == b.w { + 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 { + panic(errNegativeRead) + } + if n > 0 { + b.lastByte = int(p[n-1]) + b.lastRuneSize = -1 + } + return n, b.readErr() + } + b.fill() // buffer is empty + 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.r == b.w { + if b.err != nil { + return 0, b.readErr() + } + b.fill() // buffer is empty + } + 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 { + if b.lastByte < 0 || b.r == 0 && b.w > 0 { + return ErrInvalidUnreadByte + } + // b.r > 0 || b.w == 0 + if b.r > 0 { + b.r-- + } else { + // b.r == 0 && b.w == 0 + b.w = 1 + } + b.buf[b.r] = byte(b.lastByte) + b.lastByte = -1 + b.lastRuneSize = -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.w-b.r < len(b.buf) { + b.fill() // b.w-b.r < len(buf) => buffer is not full + } + 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 < b.lastRuneSize { + 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. +// 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) { + for { + // Search buffer. + if i := bytes.IndexByte(b.buf[b.r:b.w], delim); i >= 0 { + line = b.buf[b.r : b.r+i+1] + b.r += i + 1 + break + } + + // Pending error? + if b.err != nil { + line = b.buf[b.r:b.w] + b.r = b.w + err = b.readErr() + break + } + + // Buffer full? + if n := b.Buffered(); n >= len(b.buf) { + b.r = b.w + line = b.buf + err = ErrBufferFull + break + } + + b.fill() // buffer is not full + } + + // Handle last byte, if any. + if i := len(line) - 1; i >= 0 { + b.lastByte = int(line[i]) + } + + return +} + +// ReadN tries to read exactly n bytes. +// The bytes stop being valid at the next read call. +// If ReadN encounters an error before reading n bytes, +// it returns all the data in the buffer and the error itself (often io.EOF). +// ReadN fails with error ErrBufferFull if the buffer fills +// without reading N bytes. +// Because the data returned from ReadN will be overwritten +// by the next I/O operation, most clients should use +// ReadBytes or ReadString instead. +func (b *Reader) ReadN(n int) ([]byte, error) { + for b.Buffered() < n { + if b.err != nil { + buf := b.buf[b.r:b.w] + b.r = b.w + return buf, b.readErr() + } + + // Buffer is full? + if b.Buffered() >= len(b.buf) { + b.r = b.w + return b.buf, ErrBufferFull + } + + b.fill() + } + buf := b.buf[b.r : b.r+n] + b.r += n + return buf, nil +} + +// 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 (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. +// For simple uses, a Scanner may be more convenient. +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. +// For simple uses, a Scanner may be more convenient. +func (b *Reader) ReadString(delim byte) (line string, err error) { + bytes, err := b.ReadBytes(delim) + line = string(bytes) + return line, err +} + +// WriteTo implements io.WriterTo. +func (b *Reader) WriteTo(w io.Writer) (n int64, err error) { + n, err = b.writeBuf(w) + if err != nil { + return + } + + if r, ok := b.rd.(io.WriterTo); ok { + m, err := r.WriteTo(w) + n += m + return n, err + } + + if w, ok := w.(io.ReaderFrom); ok { + m, err := w.ReadFrom(b.rd) + n += m + return n, err + } + + if b.w-b.r < len(b.buf) { + b.fill() // buffer not full + } + + for b.r < b.w { + // b.r < b.w => buffer is not empty + m, err := b.writeBuf(w) + n += m + if err != nil { + return n, err + } + b.fill() // buffer is empty + } + + if b.err == io.EOF { + b.err = nil + } + + return n, b.readErr() +} + +// writeBuf writes the Reader's buffer to the writer. +func (b *Reader) writeBuf(w io.Writer) (int64, error) { + n, err := w.Write(b.buf[b.r:b.w]) + if n < b.r-b.w { + panic(errors.New("bufio: writer did not write all data")) + } + b.r += n + return int64(n), err +} + +// 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. +// 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 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(w io.Writer, size int) *Writer { + // Is it already a Writer? + b, ok := w.(*Writer) + if ok && len(b.buf) >= size { + return b + } + if size <= 0 { + size = defaultBufSize + } + return &Writer{ + buf: make([]byte, size), + wr: w, + } +} + +// NewWriter returns a new Writer whose buffer has the default size. +func NewWriter(w io.Writer) *Writer { + return NewWriterSize(w, defaultBufSize) +} + +// Reset discards any unflushed buffered data, clears any error, and +// resets b to write its output to w. +func (b *Writer) Reset(w io.Writer) { + b.err = nil + b.n = 0 + b.wr = w +} + +// Flush writes any buffered data to the underlying io.Writer. +func (b *Writer) Flush() error { + err := b.flush() + return err +} + +func (b *Writer) flush() error { + if b.err != nil { + return b.err + } + if b.n == 0 { + return nil + } + n, err := b.wr.Write(b.buf[0:b.n]) + if n < b.n && err == nil { + err = io.ErrShortWrite + } + if err != nil { + if n > 0 && n < b.n { + copy(b.buf[0:b.n-n], b.buf[n:b.n]) + } + b.n -= n + b.err = err + return err + } + 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 +} + +// ReadFrom implements io.ReaderFrom. +func (b *Writer) ReadFrom(r io.Reader) (n int64, err error) { + if b.Buffered() == 0 { + if w, ok := b.wr.(io.ReaderFrom); ok { + return w.ReadFrom(r) + } + } + var m int + for { + if b.Available() == 0 { + if err1 := b.flush(); err1 != nil { + return n, err1 + } + } + nr := 0 + for nr < maxConsecutiveEmptyReads { + m, err = r.Read(b.buf[b.n:]) + if m != 0 || err != nil { + break + } + nr++ + } + if nr == maxConsecutiveEmptyReads { + return n, io.ErrNoProgress + } + b.n += m + n += int64(m) + if err != nil { + break + } + } + if err == io.EOF { + // If we filled the buffer exactly, flush pre-emptively. + if b.Available() == 0 { + err = b.flush() + } else { + err = nil + } + } + return n, err +} + +// 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} +} |