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Diffstat (limited to 'indra/llcorehttp/bufferstream.h')
| -rw-r--r-- | indra/llcorehttp/bufferstream.h | 153 |
1 files changed, 153 insertions, 0 deletions
diff --git a/indra/llcorehttp/bufferstream.h b/indra/llcorehttp/bufferstream.h new file mode 100644 index 0000000000..9327a798aa --- /dev/null +++ b/indra/llcorehttp/bufferstream.h @@ -0,0 +1,153 @@ +/** + * @file bufferstream.h + * @brief Public-facing declaration for the BufferStream adapter class + * + * $LicenseInfo:firstyear=2012&license=viewerlgpl$ + * Second Life Viewer Source Code + * Copyright (C) 2012, Linden Research, Inc. + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; + * version 2.1 of the License only. + * + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + * + * Linden Research, Inc., 945 Battery Street, San Francisco, CA 94111 USA + * $/LicenseInfo$ + */ + +#ifndef _LLCORE_BUFFER_STREAM_H_ +#define _LLCORE_BUFFER_STREAM_H_ + + +#include <sstream> +#include <cstdlib> + +#include "bufferarray.h" + + +/// @file bufferstream.h +/// +/// std::streambuf and std::iostream adapters for BufferArray +/// objects. +/// +/// BufferArrayStreamBuf inherits std::streambuf and implements +/// an unbuffered interface for streambuf. This may or may not +/// be the most time efficient implementation and it is a little +/// challenging. +/// +/// BufferArrayStream inherits std::iostream and will be the +/// adapter object most callers will be interested in (though +/// it uses BufferArrayStreamBuf internally). Instances allow +/// for the usual streaming operators ('<<', '>>') and serialization +/// methods. +/// +/// Example of LLSD serialization to a BufferArray: +/// +/// BufferArray * ba = new BufferArray; +/// BufferArrayStream bas(ba); +/// LLSDSerialize::toXML(llsd, bas); +/// operationOnBufferArray(ba); +/// ba->release(); +/// ba = NULL; +/// // operationOnBufferArray and bas are each holding +/// // references to the ba instance at this point. +/// + +namespace LLCore +{ + + +// ===================================================== +// BufferArrayStreamBuf +// ===================================================== + +/// Adapter class to put a std::streambuf interface on a BufferArray +/// +/// Application developers will rarely be interested in anything +/// other than the constructor and even that will rarely be used +/// except indirectly via the @BufferArrayStream class. The +/// choice of interfaces implemented yields a bufferless adapter +/// that doesn't used either the input or output pointer triplets +/// of the more common buffered implementations. This may or may +/// not be faster and that question could stand to be looked at +/// sometime. +/// + +class BufferArrayStreamBuf : public std::streambuf +{ +public: + /// Constructor increments the reference count on the + /// BufferArray argument and calls release() on destruction. + BufferArrayStreamBuf(BufferArray * array); + virtual ~BufferArrayStreamBuf(); + +private: + BufferArrayStreamBuf(const BufferArrayStreamBuf &); // Not defined + void operator=(const BufferArrayStreamBuf &); // Not defined + +public: + // Input interfaces from std::streambuf + int_type underflow(); + int_type uflow(); + int_type pbackfail(int_type ch); + std::streamsize showmanyc(); + + // Output interfaces from std::streambuf + int_type overflow(int c); + std::streamsize xsputn(const char * src, std::streamsize count); + + // Common/misc interfaces from std::streambuf + std::streampos seekoff(std::streamoff off, std::ios_base::seekdir way, std::ios_base::openmode which); + +protected: + BufferArray * mBufferArray; // Ref counted + size_t mReadCurPos; + int mReadCurBlock; + const char * mReadBegin; + const char * mReadCur; + const char * mReadEnd; + size_t mWriteCurPos; + +}; // end class BufferArrayStreamBuf + + +// ===================================================== +// BufferArrayStream +// ===================================================== + +/// Adapter class that supplies streaming operators to BufferArray +/// +/// Provides a streaming adapter to an existing BufferArray +/// instance so that the convenient '<<' and '>>' conversions +/// can be applied to a BufferArray. Very convenient for LLSD +/// serialization and parsing as well. + +class BufferArrayStream : public std::iostream +{ +public: + /// Constructor increments the reference count on the + /// BufferArray argument and calls release() on destruction. + BufferArrayStream(BufferArray * ba); + ~BufferArrayStream(); + +protected: + BufferArrayStream(const BufferArrayStream &); + void operator=(const BufferArrayStream &); + +protected: + BufferArrayStreamBuf mStreamBuf; +}; // end class BufferArrayStream + + +} // end namespace LLCore + +#endif // _LLCORE_BUFFER_STREAM_H_ |