dcdc33b0af
* BCompressionAlgorithm is a base class for classes that provide compression/decompression functionality. There are methods for compressing/decompressing a single buffer and factory methods for a compressing/decompressing input/output BDataIO. * BZlibCompressionAlgorithm is a BCompressionAlgorithm implementation using zlib.
122 lines
3.1 KiB
C++
122 lines
3.1 KiB
C++
/*
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* Copyright 2014, Ingo Weinhold, ingo_weinhold@gmx.de.
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* Distributed under the terms of the MIT License.
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*/
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#ifndef _COMPRESSION_ALGORITHM_H_
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#define _COMPRESSION_ALGORITHM_H_
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#include <DataIO.h>
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class BCompressionParameters {
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public:
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BCompressionParameters();
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virtual ~BCompressionParameters();
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};
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class BDecompressionParameters {
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public:
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BDecompressionParameters();
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virtual ~BDecompressionParameters();
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};
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class BCompressionAlgorithm {
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public:
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BCompressionAlgorithm();
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virtual ~BCompressionAlgorithm();
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virtual status_t CreateCompressingInputStream(BDataIO* input,
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const BCompressionParameters* parameters,
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BDataIO*& _stream);
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virtual status_t CreateCompressingOutputStream(BDataIO* output,
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const BCompressionParameters* parameters,
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BDataIO*& _stream);
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virtual status_t CreateDecompressingInputStream(BDataIO* input,
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const BDecompressionParameters* parameters,
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BDataIO*& _stream);
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virtual status_t CreateDecompressingOutputStream(BDataIO* output,
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const BDecompressionParameters* parameters,
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BDataIO*& _stream);
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virtual status_t CompressBuffer(const void* input,
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size_t inputSize, void* output,
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size_t outputSize, size_t& _compressedSize,
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const BCompressionParameters* parameters
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= NULL);
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virtual status_t DecompressBuffer(const void* input,
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size_t inputSize, void* output,
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size_t outputSize,
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size_t& _uncompressedSize,
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const BDecompressionParameters* parameters
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= NULL);
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protected:
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class BAbstractStream;
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class BAbstractInputStream;
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class BAbstractOutputStream;
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};
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class BCompressionAlgorithm::BAbstractStream : public BDataIO {
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public:
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BAbstractStream();
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virtual ~BAbstractStream();
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status_t Init(size_t bufferSize);
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protected:
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virtual status_t ProcessData(const void* input, size_t inputSize,
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void* output, size_t outputSize,
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size_t& bytesConsumed,
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size_t& bytesProduced) = 0;
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// must consume or produce at least 1 byte
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// or return an error
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virtual status_t FlushPendingData(void* output,
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size_t outputSize,
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size_t& bytesProduced) = 0;
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protected:
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uint8* fBuffer;
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size_t fBufferCapacity;
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size_t fBufferOffset;
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size_t fBufferSize;
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};
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class BCompressionAlgorithm::BAbstractInputStream : public BAbstractStream {
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public:
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BAbstractInputStream(BDataIO* input);
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virtual ~BAbstractInputStream();
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virtual ssize_t Read(void* buffer, size_t size);
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private:
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BDataIO* fInput;
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bool fEndOfInput;
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bool fNoMorePendingData;
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};
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class BCompressionAlgorithm::BAbstractOutputStream : public BAbstractStream {
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public:
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BAbstractOutputStream(BDataIO* output);
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virtual ~BAbstractOutputStream();
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virtual ssize_t Write(const void* buffer, size_t size);
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virtual status_t Flush();
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private:
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ssize_t _Write(const void* buffer, size_t size,
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bool flush);
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private:
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BDataIO* fOutput;
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};
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#endif // _COMPRESSION_ALGORITHM_H_
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