114 lines
4.3 KiB
C++
114 lines
4.3 KiB
C++
/*
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* Copyright (c) 2014, Oculus VR, Inc.
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* All rights reserved.
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*
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* This source code is licensed under the BSD-style license found in the
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* LICENSE file in the root directory of this source tree. An additional grant
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* of patent rights can be found in the PATENTS file in the same directory.
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*
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*/
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/// \file
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/// \brief \b Compresses/Decompresses ASCII strings and writes/reads them to BitStream class instances. You can use this to easily serialize and deserialize your own strings.
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///
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#ifndef __STRING_COMPRESSOR_H
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#define __STRING_COMPRESSOR_H
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#include "Export.hpp"
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#include "DS_Map.hpp"
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#include "RakMemoryOverride.hpp"
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#include "NativeTypes.hpp"
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#ifdef _STD_STRING_COMPRESSOR
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#include <string>
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#endif
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/// Forward declaration
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namespace RakNet
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{
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class BitStream;
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class RakString;
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};
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namespace RakNet
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{
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/// Forward declarations
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class HuffmanEncodingTree;
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/// \brief Writes and reads strings to and from bitstreams.
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///
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/// Only works with ASCII strings. The default compression is for English.
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/// You can call GenerateTreeFromStrings to compress and decompress other languages efficiently as well.
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class RAK_DLL_EXPORT StringCompressor
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{
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public:
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// Destructor
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~StringCompressor();
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/// static function because only static functions can access static members
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/// The RakPeer constructor adds a reference to this class, so don't call this until an instance of RakPeer exists, or unless you call AddReference yourself.
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/// \return the unique instance of the StringCompressor
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static StringCompressor* Instance(void);
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/// Given an array of strings, such as a chat log, generate the optimal encoding tree for it.
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/// This function is optional and if it is not called a default tree will be used instead.
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/// \param[in] input An array of bytes which should point to text.
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/// \param[in] inputLength Length of \a input
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/// \param[in] languageID An identifier for the language / string table to generate the tree for. English is automatically created with ID 0 in the constructor.
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void GenerateTreeFromStrings( unsigned char *input, unsigned inputLength, uint8_t languageId );
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/// Writes input to output, compressed. Takes care of the null terminator for you.
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/// \param[in] input Pointer to an ASCII string
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/// \param[in] maxCharsToWrite The max number of bytes to write of \a input. Use 0 to mean no limit.
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/// \param[out] output The bitstream to write the compressed string to
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/// \param[in] languageID Which language to use
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void EncodeString( const char *input, int maxCharsToWrite, RakNet::BitStream *output, uint8_t languageId=0 );
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/// Writes input to output, uncompressed. Takes care of the null terminator for you.
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/// \param[out] output A block of bytes to receive the output
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/// \param[in] maxCharsToWrite Size, in bytes, of \a output . A NULL terminator will always be appended to the output string. If the maxCharsToWrite is not large enough, the string will be truncated.
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/// \param[in] input The bitstream containing the compressed string
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/// \param[in] languageID Which language to use
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bool DecodeString( char *output, int maxCharsToWrite, RakNet::BitStream *input, uint8_t languageId=0 );
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#ifdef _CSTRING_COMPRESSOR
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void EncodeString( const CString &input, int maxCharsToWrite, RakNet::BitStream *output, uint8_t languageId=0 );
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bool DecodeString( CString &output, int maxCharsToWrite, RakNet::BitStream *input, uint8_t languageId=0 );
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#endif
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#ifdef _STD_STRING_COMPRESSOR
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void EncodeString( const std::string &input, int maxCharsToWrite, RakNet::BitStream *output, uint8_t languageId=0 );
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bool DecodeString( std::string *output, int maxCharsToWrite, RakNet::BitStream *input, uint8_t languageId=0 );
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#endif
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void EncodeString( const RakNet::RakString *input, int maxCharsToWrite, RakNet::BitStream *output, uint8_t languageId=0 );
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bool DecodeString( RakNet::RakString *output, int maxCharsToWrite, RakNet::BitStream *input, uint8_t languageId=0 );
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/// Used so I can allocate and deallocate this singleton at runtime
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static void AddReference(void);
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/// Used so I can allocate and deallocate this singleton at runtime
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static void RemoveReference(void);
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StringCompressor();
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private:
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/// Singleton instance
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static StringCompressor *instance;
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/// Pointer to the huffman encoding trees.
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DataStructures::Map<int, HuffmanEncodingTree *> huffmanEncodingTrees;
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static int referenceCount;
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};
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} // namespace RakNet
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#endif
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