diff --git a/bzip_extent_writer.h b/bzip_extent_writer.h
new file mode 100644
index 0000000..fdd9671
--- /dev/null
+++ b/bzip_extent_writer.h
@@ -0,0 +1,38 @@
+// 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 CHROMEOS_PLATFORM_UPDATE_ENGINE_BZIP_EXTENT_WRITER_H__
+#define CHROMEOS_PLATFORM_UPDATE_ENGINE_BZIP_EXTENT_WRITER_H__
+
+#include <vector>
+#include <bzlib.h>
+#include "update_engine/extent_writer.h"
+#include "update_engine/utils.h"
+
+// BzipExtentWriter is a concrete ExtentWriter subclass that bzip-decompresses
+// what it's given in Write. It passes the decompressed data to an underlying
+// ExtentWriter.
+
+namespace chromeos_update_engine {
+
+class BzipExtentWriter : public ExtentWriter {
+ public:
+  BzipExtentWriter(ExtentWriter* next) : next_(next) {
+    memset(&stream_, 0, sizeof(stream_));
+  }
+  ~BzipExtentWriter() {}
+
+  bool Init(int fd, const std::vector<Extent>& extents, uint32 block_size);
+  bool Write(const void* bytes, size_t count);
+  bool EndImpl();
+
+ private:
+  ExtentWriter* const next_;  // The underlying ExtentWriter.
+  bz_stream stream_;  // the libbz2 stream
+  std::vector<char> input_buffer_;
+};
+
+}  // namespace chromeos_update_engine
+
+#endif  // CHROMEOS_PLATFORM_UPDATE_ENGINE_BZIP_EXTENT_WRITER_H__