Commit Brian Olson's gzip stream implementations.

1 files changed, 178 insertions, 0 deletions

diff --git a/src/google/protobuf/io/gzip_stream.h b/src/google/protobuf/io/gzip_stream.h
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+++ b/src/google/protobuf/io/gzip_stream.h
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+// Protocol Buffers - Google's data interchange format
+// Copyright 2009 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)
+//  Based on original Protocol Buffers design by
+//  Sanjay Ghemawat, Jeff Dean, and others.
+//
+// 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,
+  };
+
+  // buffer_size and format may be -1 for default of 64kB and GZIP format
+  explicit GzipOutputStream(
+      ZeroCopyOutputStream* sub_stream,
+      Format format = GZIP,
+      int buffer_size = -1);
+  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_;
+
+  // 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__