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Diffstat (limited to 'lib/compress/Compress.h')
| -rwxr-xr-x | lib/compress/Compress.h | 195 |
1 files changed, 195 insertions, 0 deletions
diff --git a/lib/compress/Compress.h b/lib/compress/Compress.h new file mode 100755 index 00000000..9b609adb --- /dev/null +++ b/lib/compress/Compress.h @@ -0,0 +1,195 @@ +// -------------------------------------------------------------------------- +// +// File +// Name: CompressContext.h +// Purpose: Interface to zlib compression +// Created: 5/12/03 +// +// -------------------------------------------------------------------------- + +#ifndef COMPRESSCONTEXT__H +#define COMPRESSCONTEXT__H + +#include <zlib.h> + +#include "CompressException.h" + +// -------------------------------------------------------------------------- +// +// Class +// Name: CompressContext +// Purpose: Interface to zlib compression, only very slight wrapper. +// (Use CompressStream for a more friendly interface.) +// Created: 5/12/03 +// +// -------------------------------------------------------------------------- +template<bool Compressing> +class Compress +{ +public: + Compress() + : mFinished(false), + mFlush(Z_NO_FLUSH) + { + // initialise stream + mStream.zalloc = Z_NULL; + mStream.zfree = Z_NULL; + mStream.opaque = Z_NULL; + mStream.data_type = Z_BINARY; + + if((Compressing)?(deflateInit(&mStream, Z_DEFAULT_COMPRESSION)) + :(inflateInit(&mStream)) != Z_OK) + { + THROW_EXCEPTION(CompressException, InitFailed) + } + + mStream.avail_in = 0; + } + + ~Compress() + { + int r = 0; + if((r = ((Compressing)?(deflateEnd(&mStream)) + :(inflateEnd(&mStream)))) != Z_OK) + { + TRACE1("zlib error code = %d\n", r); + if(r == Z_DATA_ERROR) + { + TRACE0("WARNING: End of compress/decompress without all input being consumed -- possible corruption?\n"); + } + else + { + THROW_EXCEPTION(CompressException, EndFailed) + } + } + } + + // -------------------------------------------------------------------------- + // + // Function + // Name: Compress<Function>::InputRequired() + // Purpose: Input required yet? + // Created: 5/12/03 + // + // -------------------------------------------------------------------------- + bool InputRequired() + { + return mStream.avail_in <= 0; + } + + // -------------------------------------------------------------------------- + // + // Function + // Name: Compress<Function>::Input(const void *, int) + // Purpose: Set the input buffer ready for next output call. + // Created: 5/12/03 + // + // -------------------------------------------------------------------------- + void Input(const void *pInBuffer, int InLength) + { + // Check usage + if(mStream.avail_in != 0) + { + THROW_EXCEPTION(CompressException, BadUsageInputNotRequired) + } + + // Store info + mStream.next_in = (unsigned char *)pInBuffer; + mStream.avail_in = InLength; + } + + // -------------------------------------------------------------------------- + // + // Function + // Name: Compress<Function>::FinishInput() + // Purpose: When compressing, no more input will be given. + // Created: 5/12/03 + // + // -------------------------------------------------------------------------- + void FinishInput() + { + mFlush = Z_FINISH; + } + + // -------------------------------------------------------------------------- + // + // Function + // Name: Compress<Function>::Output(void *, int) + // Purpose: Get some output data + // Created: 5/12/03 + // + // -------------------------------------------------------------------------- + int Output(void *pOutBuffer, int OutLength, bool SyncFlush = false) + { + // need more input? + if(mStream.avail_in == 0 && mFlush != Z_FINISH && !SyncFlush) + { + return 0; + } + + // Buffers + mStream.next_out = (unsigned char *)pOutBuffer; + mStream.avail_out = OutLength; + + // Call one of the functions + int flush = mFlush; + if(SyncFlush && mFlush != Z_FINISH) + { + flush = Z_SYNC_FLUSH; + } + int ret = (Compressing)?(deflate(&mStream, flush)):(inflate(&mStream, flush)); + + if(SyncFlush && ret == Z_BUF_ERROR) + { + // No progress possible. Just return 0. + return 0; + } + + // Check errors + if(ret < 0) + { + TRACE1("zlib error code = %d\n", ret); + THROW_EXCEPTION(CompressException, TransformFailed) + } + + // Parse result + if(ret == Z_STREAM_END) + { + mFinished = true; + } + + // Return how much data was output + return OutLength - mStream.avail_out; + } + + // -------------------------------------------------------------------------- + // + // Function + // Name: Compress<Function>::OutputHasFinished() + // Purpose: No more output to be recieved + // Created: 5/12/03 + // + // -------------------------------------------------------------------------- + bool OutputHasFinished() + { + return mFinished; + } + + +private: + z_stream mStream; + bool mFinished; + int mFlush; +}; + +template<typename Integer> +Integer Compress_MaxSizeForCompressedData(Integer InLen) +{ + // Conservative rendition of the info found here: http://www.gzip.org/zlib/zlib_tech.html + int blocks = (InLen + 32*1024 - 1) / (32*1024); + return InLen + (blocks * 6) + 8; +} + + +#endif // COMPRESSCONTEXT__H + |