A very basic obicount

src/obidmscolumn.c

@@ -0,0 +1,46 @@
+/****************************************************************************
+ * 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);
+}