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Diffstat (limited to 'src/pkg/bytes/buffer.go')
| -rw-r--r-- | src/pkg/bytes/buffer.go | 348 | 
1 files changed, 0 insertions, 348 deletions
| diff --git a/src/pkg/bytes/buffer.go b/src/pkg/bytes/buffer.go deleted file mode 100644 index 5de86105d..000000000 --- a/src/pkg/bytes/buffer.go +++ /dev/null @@ -1,348 +0,0 @@ -// 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 bytes - -// Simple byte buffer for marshaling data. - -import ( -	"io" -	"os" -	"utf8" -) - -// A Buffer is a variable-sized buffer of bytes with Read and Write methods. -// The zero value for Buffer is an empty buffer ready to use. -type Buffer struct { -	buf       []byte            // contents are the bytes buf[off : len(buf)] -	off       int               // read at &buf[off], write at &buf[len(buf)] -	runeBytes [utf8.UTFMax]byte // avoid allocation of slice on each WriteByte or Rune -	bootstrap [64]byte          // memory to hold first slice; helps small buffers (Printf) avoid allocation. -	lastRead  readOp            // last read operation, so that Unread* can work correctly. -} - -// The readOp constants describe the last action performed on -// the buffer, so that UnreadRune and UnreadByte can -// check for invalid usage. -type readOp int - -const ( -	opInvalid  readOp = iota // Non-read operation. -	opReadRune               // Read rune. -	opRead                   // Any other read operation. -) - -// Bytes returns a slice of the contents of the unread portion of the buffer; -// len(b.Bytes()) == b.Len().  If the caller changes the contents of the -// returned slice, the contents of the buffer will change provided there -// are no intervening method calls on the Buffer. -func (b *Buffer) Bytes() []byte { return b.buf[b.off:] } - -// String returns the contents of the unread portion of the buffer -// as a string.  If the Buffer is a nil pointer, it returns "<nil>". -func (b *Buffer) String() string { -	if b == nil { -		// Special case, useful in debugging. -		return "<nil>" -	} -	return string(b.buf[b.off:]) -} - -// Len returns the number of bytes of the unread portion of the buffer; -// b.Len() == len(b.Bytes()). -func (b *Buffer) Len() int { return len(b.buf) - b.off } - -// Truncate discards all but the first n unread bytes from the buffer. -// It is an error to call b.Truncate(n) with n > b.Len(). -func (b *Buffer) Truncate(n int) { -	b.lastRead = opInvalid -	if n == 0 { -		// Reuse buffer space. -		b.off = 0 -	} -	b.buf = b.buf[0 : b.off+n] -} - -// Reset resets the buffer so it has no content. -// b.Reset() is the same as b.Truncate(0). -func (b *Buffer) Reset() { b.Truncate(0) } - -// Grow buffer to guarantee space for n more bytes. -// Return index where bytes should be written. -func (b *Buffer) grow(n int) int { -	m := b.Len() -	// If buffer is empty, reset to recover space. -	if m == 0 && b.off != 0 { -		b.Truncate(0) -	} -	if len(b.buf)+n > cap(b.buf) { -		var buf []byte -		if b.buf == nil && n <= len(b.bootstrap) { -			buf = b.bootstrap[0:] -		} else { -			// not enough space anywhere -			buf = make([]byte, 2*cap(b.buf)+n) -			copy(buf, b.buf[b.off:]) -		} -		b.buf = buf -		b.off = 0 -	} -	b.buf = b.buf[0 : b.off+m+n] -	return b.off + m -} - -// Write appends the contents of p to the buffer.  The return -// value n is the length of p; err is always nil. -func (b *Buffer) Write(p []byte) (n int, err os.Error) { -	b.lastRead = opInvalid -	m := b.grow(len(p)) -	copy(b.buf[m:], p) -	return len(p), nil -} - -// WriteString appends the contents of s to the buffer.  The return -// value n is the length of s; err is always nil. -func (b *Buffer) WriteString(s string) (n int, err os.Error) { -	b.lastRead = opInvalid -	m := b.grow(len(s)) -	return copy(b.buf[m:], s), nil -} - -// MinRead is the minimum slice size passed to a Read call by -// Buffer.ReadFrom.  As long as the Buffer has at least MinRead bytes beyond -// what is required to hold the contents of r, ReadFrom will not grow the -// underlying buffer. -const MinRead = 512 - -// ReadFrom reads data from r until EOF and appends it to the buffer. -// The return value n is the number of bytes read. -// Any error except os.EOF encountered during the read -// is also returned. -func (b *Buffer) ReadFrom(r io.Reader) (n int64, err os.Error) { -	b.lastRead = opInvalid -	// If buffer is empty, reset to recover space. -	if b.off >= len(b.buf) { -		b.Truncate(0) -	} -	for { -		if cap(b.buf)-len(b.buf) < MinRead { -			var newBuf []byte -			// can we get space without allocation? -			if b.off+cap(b.buf)-len(b.buf) >= MinRead { -				// reuse beginning of buffer -				newBuf = b.buf[0 : len(b.buf)-b.off] -			} else { -				// not enough space at end; put space on end -				newBuf = make([]byte, len(b.buf)-b.off, 2*(cap(b.buf)-b.off)+MinRead) -			} -			copy(newBuf, b.buf[b.off:]) -			b.buf = newBuf -			b.off = 0 -		} -		m, e := r.Read(b.buf[len(b.buf):cap(b.buf)]) -		b.buf = b.buf[0 : len(b.buf)+m] -		n += int64(m) -		if e == os.EOF { -			break -		} -		if e != nil { -			return n, e -		} -	} -	return n, nil // err is EOF, so return nil explicitly -} - -// WriteTo writes data to w until the buffer is drained or an error -// occurs. The return value n is the number of bytes written; it always -// fits into an int, but it is int64 to match the io.WriterTo interface. -// Any error encountered during the write is also returned. -func (b *Buffer) WriteTo(w io.Writer) (n int64, err os.Error) { -	b.lastRead = opInvalid -	if b.off < len(b.buf) { -		m, e := w.Write(b.buf[b.off:]) -		b.off += m -		n = int64(m) -		if e != nil { -			return n, e -		} -		// otherwise all bytes were written, by definition of -		// Write method in io.Writer -	} -	// Buffer is now empty; reset. -	b.Truncate(0) -	return -} - -// WriteByte appends the byte c to the buffer. -// The returned error is always nil, but is included -// to match bufio.Writer's WriteByte. -func (b *Buffer) WriteByte(c byte) os.Error { -	b.lastRead = opInvalid -	m := b.grow(1) -	b.buf[m] = c -	return nil -} - -// WriteRune appends the UTF-8 encoding of Unicode -// code point r to the buffer, returning its length and -// an error, which is always nil but is included -// to match bufio.Writer's WriteRune. -func (b *Buffer) WriteRune(r int) (n int, err os.Error) { -	if r < utf8.RuneSelf { -		b.WriteByte(byte(r)) -		return 1, nil -	} -	n = utf8.EncodeRune(b.runeBytes[0:], r) -	b.Write(b.runeBytes[0:n]) -	return n, nil -} - -// Read reads the next len(p) bytes from the buffer or until the buffer -// is drained.  The return value n is the number of bytes read.  If the -// buffer has no data to return, err is os.EOF even if len(p) is zero; -// otherwise it is nil. -func (b *Buffer) Read(p []byte) (n int, err os.Error) { -	b.lastRead = opInvalid -	if b.off >= len(b.buf) { -		// Buffer is empty, reset to recover space. -		b.Truncate(0) -		return 0, os.EOF -	} -	n = copy(p, b.buf[b.off:]) -	b.off += n -	if n > 0 { -		b.lastRead = opRead -	} -	return -} - -// Next returns a slice containing the next n bytes from the buffer, -// advancing the buffer as if the bytes had been returned by Read. -// If there are fewer than n bytes in the buffer, Next returns the entire buffer. -// The slice is only valid until the next call to a read or write method. -func (b *Buffer) Next(n int) []byte { -	b.lastRead = opInvalid -	m := b.Len() -	if n > m { -		n = m -	} -	data := b.buf[b.off : b.off+n] -	b.off += n -	if n > 0 { -		b.lastRead = opRead -	} -	return data -} - -// ReadByte reads and returns the next byte from the buffer. -// If no byte is available, it returns error os.EOF. -func (b *Buffer) ReadByte() (c byte, err os.Error) { -	b.lastRead = opInvalid -	if b.off >= len(b.buf) { -		// Buffer is empty, reset to recover space. -		b.Truncate(0) -		return 0, os.EOF -	} -	c = b.buf[b.off] -	b.off++ -	b.lastRead = opRead -	return c, nil -} - -// ReadRune reads and returns the next UTF-8-encoded -// Unicode code point from the buffer. -// If no bytes are available, the error returned is os.EOF. -// If the bytes are an erroneous UTF-8 encoding, it -// consumes one byte and returns U+FFFD, 1. -func (b *Buffer) ReadRune() (r int, size int, err os.Error) { -	b.lastRead = opInvalid -	if b.off >= len(b.buf) { -		// Buffer is empty, reset to recover space. -		b.Truncate(0) -		return 0, 0, os.EOF -	} -	b.lastRead = opReadRune -	c := b.buf[b.off] -	if c < utf8.RuneSelf { -		b.off++ -		return int(c), 1, nil -	} -	r, n := utf8.DecodeRune(b.buf[b.off:]) -	b.off += n -	return r, n, nil -} - -// UnreadRune unreads the last rune returned by ReadRune. -// If the most recent read or write 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 *Buffer) UnreadRune() os.Error { -	if b.lastRead != opReadRune { -		return os.NewError("bytes.Buffer: UnreadRune: previous operation was not ReadRune") -	} -	b.lastRead = opInvalid -	if b.off > 0 { -		_, n := utf8.DecodeLastRune(b.buf[0:b.off]) -		b.off -= n -	} -	return nil -} - -// UnreadByte unreads the last byte returned by the most recent -// read operation.  If write has happened since the last read, UnreadByte -// returns an error. -func (b *Buffer) UnreadByte() os.Error { -	if b.lastRead != opReadRune && b.lastRead != opRead { -		return os.NewError("bytes.Buffer: UnreadByte: previous operation was not a read") -	} -	b.lastRead = opInvalid -	if b.off > 0 { -		b.off-- -	} -	return nil -} - -// 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 os.EOF). -// ReadBytes returns err != nil if and only if the returned data does not end in -// delim. -func (b *Buffer) ReadBytes(delim byte) (line []byte, err os.Error) { -	i := IndexByte(b.buf[b.off:], delim) -	size := i + 1 -	if i < 0 { -		size = len(b.buf) - b.off -		err = os.EOF -	} -	line = make([]byte, size) -	copy(line, b.buf[b.off:]) -	b.off += size -	return -} - -// 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 os.EOF). -// ReadString returns err != nil if and only if the returned data does not end -// in delim. -func (b *Buffer) ReadString(delim byte) (line string, err os.Error) { -	bytes, err := b.ReadBytes(delim) -	return string(bytes), err -} - -// NewBuffer creates and initializes a new Buffer using buf as its initial -// contents.  It is intended to prepare a Buffer to read existing data.  It -// can also be used to size the internal buffer for writing.  To do that, -// buf should have the desired capacity but a length of zero. -func NewBuffer(buf []byte) *Buffer { return &Buffer{buf: buf} } - -// NewBufferString creates and initializes a new Buffer using string s as its -// initial contents.  It is intended to prepare a buffer to read an existing -// string. -func NewBufferString(s string) *Buffer { -	return &Buffer{buf: []byte(s)} -} | 
