diff --git a/decompressing_file_writer.h b/decompressing_file_writer.h
new file mode 100644
index 0000000..975ca3c
--- /dev/null
+++ b/decompressing_file_writer.h
@@ -0,0 +1,60 @@
+// Copyright (c) 2009 The Chromium OS Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef UPDATE_ENGINE_DECOMPRESSING_FILE_WRITER_H__
+#define UPDATE_ENGINE_DECOMPRESSING_FILE_WRITER_H__
+
+#include <zlib.h>
+#include "base/basictypes.h"
+#include "update_engine/file_writer.h"
+
+// GzipDecompressingFileWriter is an implementation of FileWriter. It will
+// gzip decompress all data that is passed via Write() onto another FileWriter,
+// which is responsible for actually writing the data out. Calls to
+// Open and Close are passed through to the other FileWriter.
+
+namespace chromeos_update_engine {
+
+class GzipDecompressingFileWriter : public FileWriter {
+ public:
+  explicit GzipDecompressingFileWriter(FileWriter* next) : next_(next) {
+    memset(&stream_, 0, sizeof(stream_));
+    CHECK_EQ(inflateInit2(&stream_, 16 + MAX_WBITS), Z_OK);
+  }
+  virtual ~GzipDecompressingFileWriter() {
+    inflateEnd(&stream_);
+  }
+
+  virtual int Open(const char* path, int flags, mode_t mode) {
+    return next_->Open(path, flags, mode);
+  }
+
+  // Write() calls into zlib to decompress the bytes passed in. It will not
+  // necessarily write all the decompressed data associated with this set of
+  // passed-in compressed data during this call, however for a valid gzip
+  // stream, after the entire stream has been written to this object,
+  // the entire decompressed stream will have been written to the
+  // underlying FileWriter.
+  virtual int Write(const void* bytes, size_t count);
+
+  virtual int Close() {
+    return next_->Close();
+  }
+ private:
+  // The FileWriter that we write all uncompressed data to
+  FileWriter* next_;
+
+  // The zlib state
+  z_stream stream_;
+
+  // This is for an optimization in Write(). We can keep this buffer around
+  // in our class to avoid repeated calls to malloc().
+  std::vector<char> buffer_;
+
+  DISALLOW_COPY_AND_ASSIGN(GzipDecompressingFileWriter);
+};
+
+}  // namespace chromeos_update_engine
+
+#endif  // UPDATE_ENGINE_DECOMPRESSING_FILE_WRITER_H__