src/include/cdb/cdbparquetfooterbuffer.h

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 * 
 *   http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

#ifndef CDBPARQUETFOOTERBUFFER_H_
#define CDBPARQUETFOOTERBUFFER_H_

#include "postgres.h"
#include "storage/fd.h"

#define PARQUET_FOOTER_BUFFERMODE_READ 			0x1
#define PARQUET_FOOTER_BUFFERMODE_WRITE			0X2

#define PARQUET_FOOTER_BUFFER_CAPACITY_DEFAULT	16*1024

typedef struct ParquetFooterBuffer {
    
    int      Mode;            /* The mode of the buffer.                      */
    
	char    *FileName;		  /* The name of current file for error reporting.*/
	
    File 	 FileHandler;	  /* The handler of the file with offset adjusted.*/
    
	int		 FooterLength;	  /* The total length of the footer.			  */
                              /* FooterLength is useful for reading only.     */
    
	int		 FooterProcessed; /* The processed amount of bytes of this footer.*/
                              /* For reading, FooterProcessed saves bytes read*/
                              /* For writing, FooterProcessed saves the bytes */
                              /* already written to the buffer,unnecessary to */
                              /* be one legal footer structure data.          */
    
	int		 Capacity;        /* The capacity of this buffer.				  */
    
	int		 ValidLen;        /* The valid length of the content in buffer.   */
                              /* ValidLen is useful for reading only.         */

	int		 Cursor;	      /* The cursor for reading data in buffer.       */
                              /* For reading, Cursor is the first byte to read*/
                              /* For writing, Cursor is the last valid byte   */

	uint8_t *Head;	          /* The address of the buffer.                   */
    
    File     TmpFile;         /* The temporary file for footer write buffer.  */

} ParquetFooterBuffer;

#define PARQUET_FOOTER_BUFFER_MOVE_OK		0x0
#define PARQUET_FOOTER_BUFFER_MOVE_ERROR	0x1

ParquetFooterBuffer *createParquetFooterBuffer( File  dataFile, 
												char *filename,
												int   footerlength, 
												int   capacity,
												int   mode);

void freeParquetFooterBuffer( ParquetFooterBuffer *buffer);

int  prepareFooterBufferForwardReading( ParquetFooterBuffer  *buffer,
                                        int                   length,
                                        uint8_t             **ptr);

void writeToFooterBuffer( ParquetFooterBuffer *buffer,
                          uint8_t             *content,
                          int                  length);

void flushFooterBufferToTempFile( ParquetFooterBuffer *buffer);

int appendFooterBufferTempData(File targetFile, ParquetFooterBuffer *buffer);

#endif /* CDBPARQUETFOOTERBUFFER_H_  */