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-rw-r--r--xpcom/io/SnappyFrameUtils.h85
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diff --git a/xpcom/io/SnappyFrameUtils.h b/xpcom/io/SnappyFrameUtils.h
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+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_SnappyFrameUtils_h__
+#define mozilla_SnappyFrameUtils_h__
+
+#include "mozilla/Attributes.h"
+#include "nsError.h"
+
+namespace mozilla {
+namespace detail {
+
+//
+// Utility class providing primitives necessary to build streams based
+// on the snappy compressor. This essentially abstracts the framing format
+// defined in:
+//
+// other-licences/snappy/src/framing_format.txt
+//
+// NOTE: Currently only the StreamIdentifier and CompressedData chunks are
+// supported.
+//
+class SnappyFrameUtils
+{
+public:
+ enum ChunkType
+ {
+ Unknown,
+ StreamIdentifier,
+ CompressedData,
+ UncompressedData,
+ Padding,
+ Reserved,
+ ChunkTypeCount
+ };
+
+ static const size_t kChunkTypeLength = 1;
+ static const size_t kChunkLengthLength = 3;
+ static const size_t kHeaderLength = kChunkTypeLength + kChunkLengthLength;
+ static const size_t kStreamIdentifierDataLength = 6;
+ static const size_t kCRCLength = 4;
+
+ static nsresult
+ WriteStreamIdentifier(char* aDest, size_t aDestLength,
+ size_t* aBytesWrittenOut);
+
+ static nsresult
+ WriteCompressedData(char* aDest, size_t aDestLength,
+ const char* aData, size_t aDataLength,
+ size_t* aBytesWrittenOut);
+
+ static nsresult
+ ParseHeader(const char* aSource, size_t aSourceLength, ChunkType* aTypeOut,
+ size_t* aDataLengthOut);
+
+ static nsresult
+ ParseData(char* aDest, size_t aDestLength,
+ ChunkType aType, const char* aData, size_t aDataLength,
+ size_t* aBytesWrittenOut, size_t* aBytesReadOut);
+
+ static nsresult
+ ParseStreamIdentifier(char* aDest, size_t aDestLength,
+ const char* aData, size_t aDataLength,
+ size_t* aBytesWrittenOut, size_t* aBytesReadOut);
+
+ static nsresult
+ ParseCompressedData(char* aDest, size_t aDestLength,
+ const char* aData, size_t aDataLength,
+ size_t* aBytesWrittenOut, size_t* aBytesReadOut);
+
+ static size_t
+ MaxCompressedBufferLength(size_t aSourceLength);
+
+protected:
+ SnappyFrameUtils() { }
+ virtual ~SnappyFrameUtils() { }
+};
+
+} // namespace detail
+} // namespace mozilla
+
+#endif // mozilla_SnappyFrameUtils_h__