89 lines
3.1 KiB
C++
89 lines
3.1 KiB
C++
/* Copyright (c) 2010 Wildfire Games
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*
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* Permission is hereby granted, free of charge, to any person obtaining
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* a copy of this software and associated documentation files (the
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* "Software"), to deal in the Software without restriction, including
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* without limitation the rights to use, copy, modify, merge, publish,
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* distribute, sublicense, and/or sell copies of the Software, and to
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* permit persons to whom the Software is furnished to do so, subject to
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* the following conditions:
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*
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* The above copyright notice and this permission notice shall be included
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* in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
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* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
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* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
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* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
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* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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*/
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/*
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* this layer allows for other compression methods/libraries
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* besides ZLib. it also simplifies the interface for user code and
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* does error checking, etc.
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*/
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#ifndef INCLUDED_CODEC
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#define INCLUDED_CODEC
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#define CODEC_COMPUTE_CHECKSUM 1
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struct ICodec
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{
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public:
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/**
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* note: the implementation should not check whether any data remains -
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* codecs are sometimes destroyed without completing a transfer.
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**/
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virtual ~ICodec();
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/**
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* @return an upper bound on the output size for the given amount of input.
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* this is used when allocating a single buffer for the whole operation.
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**/
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virtual size_t MaxOutputSize(size_t inSize) const = 0;
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/**
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* clear all previous state and prepare for reuse.
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*
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* this is as if the object were destroyed and re-created, but more
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* efficient since it avoids reallocating a considerable amount of
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* memory (about 200KB for LZ).
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**/
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virtual LibError Reset() = 0;
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/**
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* process (i.e. compress or decompress) data.
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*
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* @param outSize bytes remaining in the output buffer; shall not be zero.
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* @param inConsumed, outProduced how many bytes in the input and
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* output buffers were used. either or both of these can be zero if
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* the input size is small or there's not enough output space.
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**/
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virtual LibError Process(const u8* in, size_t inSize, u8* out, size_t outSize, size_t& inConsumed, size_t& outProduced) = 0;
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/**
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* flush buffers and make sure all output has been produced.
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*
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* @param checksum over all input data.
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* @return error status for the entire operation.
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**/
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virtual LibError Finish(u32& checksum, size_t& outProduced) = 0;
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/**
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* update a checksum to reflect the contents of a buffer.
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*
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* @param checksum the initial value (must be 0 on first call)
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* @return the new checksum. note: after all data has been seen, this is
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* identical to the what Finish would return.
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**/
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virtual u32 UpdateChecksum(u32 checksum, const u8* in, size_t inSize) const = 0;
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};
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typedef shared_ptr<ICodec> PICodec;
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#endif // #ifndef INCLUDED_CODEC
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