/****************************************************************************
 * OBIDMSColumn functions                                                   *
 ****************************************************************************/

/**
 * @file obidmscolumn.h
 * @author Celine Mercier
 * @date 22 May 2015
 * @brief Functions for the shared elements of all the OBIColumn structures.
 */


#include <stdio.h>
#include <stdlib.h>
#include <sys/mman.h>	/* mmap() is defined in this header */


/**
 * @brief Reads a memory block from a file.
 *
 * * @param file The file that should be mapped.
 * * @param size The number of bytes that should be mapped.
 * * @param start The position at which the mapping should start.
 * @return A pointer on the first element of the block.
 */
char* obi_map_read_only(int file, int start, int size)
{
	char* map;
	map = (char*) mmap(0, size, PROT_READ, MAP_PRIVATE, file, start);
	if (map == MAP_FAILED)
	{
		fprintf(stderr, "\nmmap read-only error\n");
		exit(1);
	}
	return(map);
}

/**
 * @brief Unmaps a memory block.
 *
 * * @param size The size of the block that should be unmapped.
 */
void obi_unmap(int size)
{
	munmap(0, size);
}