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+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc. All rights reserved.
+// http://code.google.com/p/protobuf/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+// * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+// * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+// * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// Author: brianolson@google.com (Brian Olson)
+//
+// This file contains the definition for classes GzipInputStream and
+// GzipOutputStream.
+//
+// GzipInputStream decompresses data from an underlying
+// ZeroCopyInputStream and provides the decompressed data as a
+// ZeroCopyInputStream.
+//
+// GzipOutputStream is an ZeroCopyOutputStream that compresses data to
+// an underlying ZeroCopyOutputStream.
+
+#ifndef GOOGLE_PROTOBUF_IO_GZIP_STREAM_H__
+#define GOOGLE_PROTOBUF_IO_GZIP_STREAM_H__
+
+#include <zlib.h>
+
+#include <google/protobuf/io/zero_copy_stream.h>
+
+namespace google {
+namespace protobuf {
+namespace io {
+
+// A ZeroCopyInputStream that reads compressed data through zlib
+class LIBPROTOBUF_EXPORT GzipInputStream : public ZeroCopyInputStream {
+ public:
+ // Format key for constructor
+ enum Format {
+ // zlib will autodetect gzip header or deflate stream
+ AUTO = 0,
+
+ // GZIP streams have some extra header data for file attributes.
+ GZIP = 1,
+
+ // Simpler zlib stream format.
+ ZLIB = 2,
+ };
+
+ // buffer_size and format may be -1 for default of 64kB and GZIP format
+ explicit GzipInputStream(
+ ZeroCopyInputStream* sub_stream,
+ Format format = AUTO,
+ int buffer_size = -1);
+ virtual ~GzipInputStream();
+
+ // Return last error message or NULL if no error.
+ inline const char* ZlibErrorMessage() const {
+ return zcontext_.msg;
+ }
+ inline int ZlibErrorCode() const {
+ return zerror_;
+ }
+
+ // implements ZeroCopyInputStream ----------------------------------
+ bool Next(const void** data, int* size);
+ void BackUp(int count);
+ bool Skip(int count);
+ int64 ByteCount() const;
+
+ private:
+ Format format_;
+
+ ZeroCopyInputStream* sub_stream_;
+
+ z_stream zcontext_;
+ int zerror_;
+
+ void* output_buffer_;
+ void* output_position_;
+ size_t output_buffer_length_;
+
+ int Inflate(int flush);
+ void DoNextOutput(const void** data, int* size);
+
+ GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(GzipInputStream);
+};
+
+
+class LIBPROTOBUF_EXPORT GzipOutputStream : public ZeroCopyOutputStream {
+ public:
+ // Format key for constructor
+ enum Format {
+ // GZIP streams have some extra header data for file attributes.
+ GZIP = 1,
+
+ // Simpler zlib stream format.
+ ZLIB = 2,
+ };
+
+ struct Options {
+ // Defaults to GZIP.
+ Format format;
+
+ // What size buffer to use internally. Defaults to 64kB.
+ int buffer_size;
+
+ // A number between 0 and 9, where 0 is no compression and 9 is best
+ // compression. Defaults to Z_DEFAULT_COMPRESSION (see zlib.h).
+ int compression_level;
+
+ // Defaults to Z_DEFAULT_STRATEGY. Can also be set to Z_FILTERED,
+ // Z_HUFFMAN_ONLY, or Z_RLE. See the documentation for deflateInit2 in
+ // zlib.h for definitions of these constants.
+ int compression_strategy;
+
+ Options(); // Initializes with default values.
+ };
+
+ // Create a GzipOutputStream with default options.
+ explicit GzipOutputStream(ZeroCopyOutputStream* sub_stream);
+
+ // Create a GzipOutputStream with the given options.
+ GzipOutputStream(
+ ZeroCopyOutputStream* sub_stream,
+ const Options& options);
+
+ // DEPRECATED: Use one of the above constructors instead.
+ GzipOutputStream(
+ ZeroCopyOutputStream* sub_stream,
+ Format format,
+ int buffer_size = -1) GOOGLE_ATTRIBUTE_DEPRECATED;
+
+ virtual ~GzipOutputStream();
+
+ // Return last error message or NULL if no error.
+ inline const char* ZlibErrorMessage() const {
+ return zcontext_.msg;
+ }
+ inline int ZlibErrorCode() const {
+ return zerror_;
+ }
+
+ // Flushes data written so far to zipped data in the underlying stream.
+ // It is the caller's responsibility to flush the underlying stream if
+ // necessary.
+ // Compression may be less efficient stopping and starting around flushes.
+ // Returns true if no error.
+ bool Flush();
+
+ // Writes out all data and closes the gzip stream.
+ // It is the caller's responsibility to close the underlying stream if
+ // necessary.
+ // Returns true if no error.
+ bool Close();
+
+ // implements ZeroCopyOutputStream ---------------------------------
+ bool Next(void** data, int* size);
+ void BackUp(int count);
+ int64 ByteCount() const;
+
+ private:
+ ZeroCopyOutputStream* sub_stream_;
+ // Result from calling Next() on sub_stream_
+ void* sub_data_;
+ int sub_data_size_;
+
+ z_stream zcontext_;
+ int zerror_;
+ void* input_buffer_;
+ size_t input_buffer_length_;
+
+ // Shared constructor code.
+ void Init(ZeroCopyOutputStream* sub_stream, const Options& options);
+
+ // Do some compression.
+ // Takes zlib flush mode.
+ // Returns zlib error code.
+ int Deflate(int flush);
+
+ GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(GzipOutputStream);
+};
+
+} // namespace io
+} // namespace protobuf
+
+} // namespace google
+#endif // GOOGLE_PROTOBUF_IO_GZIP_STREAM_H__