1 files changed, 244 insertions, 0 deletions
diff --git a/libgo/go/archive/zip/writer.go b/libgo/go/archive/zip/writer.go
new file mode 100644
index 0000000..2065b06
--- /dev/null
+++ b/libgo/go/archive/zip/writer.go
@@ -0,0 +1,244 @@
+// Copyright 2011 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 zip
+
+import (
+	"bufio"
+	"compress/flate"
+	"encoding/binary"
+	"hash"
+	"hash/crc32"
+	"io"
+	"os"
+)
+
+// TODO(adg): support zip file comments
+// TODO(adg): support specifying deflate level
+
+// Writer implements a zip file writer.
+type Writer struct {
+	*countWriter
+	dir    []*header
+	last   *fileWriter
+	closed bool
+}
+
+type header struct {
+	*FileHeader
+	offset uint32
+}
+
+// NewWriter returns a new Writer writing a zip file to w.
+func NewWriter(w io.Writer) *Writer {
+	return &Writer{countWriter: &countWriter{w: bufio.NewWriter(w)}}
+}
+
+// Close finishes writing the zip file by writing the central directory.
+// It does not (and can not) close the underlying writer.
+func (w *Writer) Close() (err os.Error) {
+	if w.last != nil && !w.last.closed {
+		if err = w.last.close(); err != nil {
+			return
+		}
+		w.last = nil
+	}
+	if w.closed {
+		return os.NewError("zip: writer closed twice")
+	}
+	w.closed = true
+
+	defer recoverError(&err)
+
+	// write central directory
+	start := w.count
+	for _, h := range w.dir {
+		write(w, uint32(directoryHeaderSignature))
+		write(w, h.CreatorVersion)
+		write(w, h.ReaderVersion)
+		write(w, h.Flags)
+		write(w, h.Method)
+		write(w, h.ModifiedTime)
+		write(w, h.ModifiedDate)
+		write(w, h.CRC32)
+		write(w, h.CompressedSize)
+		write(w, h.UncompressedSize)
+		write(w, uint16(len(h.Name)))
+		write(w, uint16(len(h.Extra)))
+		write(w, uint16(len(h.Comment)))
+		write(w, uint16(0)) // disk number start
+		write(w, uint16(0)) // internal file attributes
+		write(w, uint32(0)) // external file attributes
+		write(w, h.offset)
+		writeBytes(w, []byte(h.Name))
+		writeBytes(w, h.Extra)
+		writeBytes(w, []byte(h.Comment))
+	}
+	end := w.count
+
+	// write end record
+	write(w, uint32(directoryEndSignature))
+	write(w, uint16(0))          // disk number
+	write(w, uint16(0))          // disk number where directory starts
+	write(w, uint16(len(w.dir))) // number of entries this disk
+	write(w, uint16(len(w.dir))) // number of entries total
+	write(w, uint32(end-start))  // size of directory
+	write(w, uint32(start))      // start of directory
+	write(w, uint16(0))          // size of comment
+
+	return w.w.(*bufio.Writer).Flush()
+}
+
+// Create adds a file to the zip file using the provided name.
+// It returns a Writer to which the file contents should be written.
+// The file's contents must be written to the io.Writer before the next
+// call to Create, CreateHeader, or Close.
+func (w *Writer) Create(name string) (io.Writer, os.Error) {
+	header := &FileHeader{
+		Name:   name,
+		Method: Deflate,
+	}
+	return w.CreateHeader(header)
+}
+
+// CreateHeader adds a file to the zip file using the provided FileHeader
+// for the file metadata. 
+// It returns a Writer to which the file contents should be written.
+// The file's contents must be written to the io.Writer before the next
+// call to Create, CreateHeader, or Close.
+func (w *Writer) CreateHeader(fh *FileHeader) (io.Writer, os.Error) {
+	if w.last != nil && !w.last.closed {
+		if err := w.last.close(); err != nil {
+			return nil, err
+		}
+	}
+
+	fh.Flags |= 0x8 // we will write a data descriptor
+	fh.CreatorVersion = 0x14
+	fh.ReaderVersion = 0x14
+
+	fw := &fileWriter{
+		zipw:      w,
+		compCount: &countWriter{w: w},
+		crc32:     crc32.NewIEEE(),
+	}
+	switch fh.Method {
+	case Store:
+		fw.comp = nopCloser{fw.compCount}
+	case Deflate:
+		fw.comp = flate.NewWriter(fw.compCount, 5)
+	default:
+		return nil, UnsupportedMethod
+	}
+	fw.rawCount = &countWriter{w: fw.comp}
+
+	h := &header{
+		FileHeader: fh,
+		offset:     uint32(w.count),
+	}
+	w.dir = append(w.dir, h)
+	fw.header = h
+
+	if err := writeHeader(w, fh); err != nil {
+		return nil, err
+	}
+
+	w.last = fw
+	return fw, nil
+}
+
+func writeHeader(w io.Writer, h *FileHeader) (err os.Error) {
+	defer recoverError(&err)
+	write(w, uint32(fileHeaderSignature))
+	write(w, h.ReaderVersion)
+	write(w, h.Flags)
+	write(w, h.Method)
+	write(w, h.ModifiedTime)
+	write(w, h.ModifiedDate)
+	write(w, h.CRC32)
+	write(w, h.CompressedSize)
+	write(w, h.UncompressedSize)
+	write(w, uint16(len(h.Name)))
+	write(w, uint16(len(h.Extra)))
+	writeBytes(w, []byte(h.Name))
+	writeBytes(w, h.Extra)
+	return nil
+}
+
+type fileWriter struct {
+	*header
+	zipw      io.Writer
+	rawCount  *countWriter
+	comp      io.WriteCloser
+	compCount *countWriter
+	crc32     hash.Hash32
+	closed    bool
+}
+
+func (w *fileWriter) Write(p []byte) (int, os.Error) {
+	if w.closed {
+		return 0, os.NewError("zip: write to closed file")
+	}
+	w.crc32.Write(p)
+	return w.rawCount.Write(p)
+}
+
+func (w *fileWriter) close() (err os.Error) {
+	if w.closed {
+		return os.NewError("zip: file closed twice")
+	}
+	w.closed = true
+	if err = w.comp.Close(); err != nil {
+		return
+	}
+
+	// update FileHeader
+	fh := w.header.FileHeader
+	fh.CRC32 = w.crc32.Sum32()
+	fh.CompressedSize = uint32(w.compCount.count)
+	fh.UncompressedSize = uint32(w.rawCount.count)
+
+	// write data descriptor
+	defer recoverError(&err)
+	write(w.zipw, fh.CRC32)
+	write(w.zipw, fh.CompressedSize)
+	write(w.zipw, fh.UncompressedSize)
+
+	return nil
+}
+
+type countWriter struct {
+	w     io.Writer
+	count int64
+}
+
+func (w *countWriter) Write(p []byte) (int, os.Error) {
+	n, err := w.w.Write(p)
+	w.count += int64(n)
+	return n, err
+}
+
+type nopCloser struct {
+	io.Writer
+}
+
+func (w nopCloser) Close() os.Error {
+	return nil
+}
+
+func write(w io.Writer, data interface{}) {
+	if err := binary.Write(w, binary.LittleEndian, data); err != nil {
+		panic(err)
+	}
+}
+
+func writeBytes(w io.Writer, b []byte) {
+	n, err := w.Write(b)
+	if err != nil {
+		panic(err)
+	}
+	if n != len(b) {
+		panic(io.ErrShortWrite)
+	}
+}