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writeengine/bulk/we_colbufcompressed.h

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+/* Copyright (C) 2014 InfiniDB, Inc.
+
+   This program is free software; you can redistribute it and/or
+   modify it under the terms of the GNU General Public License
+   as published by the Free Software Foundation; version 2 of
+   the License.
+
+   This program 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 General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+   MA 02110-1301, USA. */
+
+/******************************************************************************
+ * $Id: we_colbufcompressed.h 4726 2013-08-07 03:38:36Z bwilkinson $
+ *
+ *****************************************************************************/
+
+/** @file
+ * class ColumnBufferCompressed
+ */
+
+#ifndef WRITEENGINE_COLUMNBUFCOMPRESSED_H
+#define WRITEENGINE_COLUMNBUFCOMPRESSED_H
+
+#include "we_colbuf.h"
+
+#include <cstdio>
+#include <vector>
+
+#include "idbcompress.h"
+
+namespace WriteEngine {
+class Log;
+struct ColumnInfo;
+
+/** @brief A buffer class to store data written to compressed column files
+ *
+ * ColumnBufferCompressed is to be used as a temporary buffer to store
+ * compressed column data before writing it out to the intended destination
+ * (currently a file stream). The file stream should be initialized by
+ * the client of this class
+ */
+class ColumnBufferCompressed : public ColumnBuffer {
+
+  public:
+
+    /** @brief default Constructor
+     */
+    ColumnBufferCompressed( ColumnInfo* pColInfo, Log* logger);
+
+    /** @brief default Destructor
+     */
+    virtual ~ColumnBufferCompressed();
+
+    /** @brief Final flushing of data and headers prior to closing the file.
+     * @param bTruncFile is file to be truncated
+     * @return NO_ERROR or success
+     */
+    virtual int finishFile(bool bTruncFile);
+
+    /** @brief Reset the ColBuf to-be-compressed buffer prior to importing the
+     * next extent.
+     * @param startFileOffset Byte offset where next extent chunk will start
+     */
+    virtual int resetToBeCompressedColBuf(long long& startFileOffset );
+
+    /** @brief file mutator
+     *
+     * @param cFile    Destination FILE stream where buffer data will be written
+     * @param startHwm Starting HWM for cFile
+     * @param hdrs     Headers with ptr information.
+     */
+    virtual int setDbFile(IDBDataFile * const cFile, HWM startHwm, const char* hdrs);
+
+    /** @brief Write data to FILE
+     *
+     * @param startOffset The buffer offset from where the write should begin
+     * @param writeSize   The number of bytes to be written to the file
+     */
+    virtual int writeToFile(int startOffset, int writeSize);
+
+  private:
+
+    // Disable copy constructor and assignment operator by declaring and
+    // not defining.
+    ColumnBufferCompressed(const ColumnBufferCompressed&);
+    ColumnBufferCompressed& operator=(const ColumnBufferCompressed&);
+
+    // Compress and flush the to-be-compressed buffer; updates header if needed
+    int compressAndFlush(bool bFinishFile);
+    int initToBeCompressedBuffer( long long& startFileOffset);
+                                // Initialize the to-be-compressed buffer
+    int saveCompressionHeaders(); // Saves compression headers to the db file
+
+    unsigned char*       fToBeCompressedBuffer; // data waiting to be compressed
+    size_t               fToBeCompressedCapacity;//size of comp buffer;
+                                                // should always be 4MB, unless
+                                                // working with abbrev extent.
+    size_t               fNumBytes;             // num Bytes in comp buffer
+    compress::IDBCompressInterface*
+                         fCompressor;           // data compression object
+    compress::CompChunkPtrList
+                         fChunkPtrs;            // col file header information
+    bool                 fPreLoadHWMChunk;      // preload 1st HWM chunk only
+    unsigned int         fUserPaddingBytes;     // compressed chunk padding
+    bool                 fFlushedStartHwmChunk; // have we rewritten the hdr
+                                                //   for the starting HWM chunk
+};
+
+}
+
+#endif //WRITEENGINE_COLUMNBUFCOMPRESSED_H