Task

The goal of this assignment is to implement a simple storage manager $-$ a module that is capable of reading blocks

from a file on disk into memory and writing blocks from memory to a file on disk. The storage manager deals with

pages $($blocks$)$ of fixed size $($PAGE$\_$SIZE$).$ In addition to reading and writing pages from a file, it provides methods for

creating, opening, and closing files. The storage manager has to maintain several types of information for an open

file: The number of total pages in the file, the current page position $($for reading and writing$),$ the file name, and a

POSIX file descriptor or FILE pointer. In your implementation you should implement the interface described below.

Please commit a text file README. txt that $($shortly$)$ describes the ideas behind your solution and the code structure.

Comment your code!

INTERFACE

The interface your storage manager should implement is given as a header file storage$\_$mgr$.$h$.$ The content of this

header is shown below. Two additional headers

and test$\_$helpers.h define error codes and constants

and macros used in the test cases.

#ifndef STORAGE$\_$MGR$\_$H

#define STORAGE$\_$MGR$\_$H

#include "dberror.h$"$

$\frac{?}{?}************************************************************************************************************************$

handle data structures

$***********************************************************************************************************************\frac{*}{?}$

typedef struct SM$\_$FileHandle $\{$

char $*$ fileName;

int totalNumPages;

int curPagePos;

void $*$mgmtInfo;

$\}$ SM$\_$FileHandle;

typedef char $*$ SM$\_$PageHandle;

$\frac{?}{?}************************************************************************************************************************$

$,$ interface

$***********************************************************************************************************************\frac{*}{?}$

$/*$ manipulating page files $*/$

extern void initStorageManager $($void$)$;

extern RC createPageFile $($char $*$ fileName$)$;

extern RC openPageFile $($char $*$fileName$,$ SM$\_$FileHandle $*$fHandle$)$;

extern RC closePageFile $($SM$\_$FileHandle $*$fHandle$)$;

extern RC destroyPageFile $($char $*$ fileName$)$;

$/*$ reading blocks from disc $*/$

extern RC readBlock $($int pageNum, SM$\_$FileHandle $*$fHandle$,$ SM$\_$PageHandle memPage$)$;

extern int getBlockPos $($SM$\_$FileHandle $*$fHandle$)$;

extern RC readFirstBlock $($SM$\_$FileHandle $*$fHandle$,$ SM$\_$PageHandle memPage$)$;

extern RC readPreviousBlock $($SM$\_$FileHandle $*$fHandle$,$ SM$\_$PageHandle memPage$)$;

extern RC readCurrentBlock $($SM$\_$FileHandle $*$fHandle$,$ SM$\_$PageHandle memPage$)$;

extern RC readNextBlock $($SM$\_$FileHandle $*$fHandle$,$ SM$\_$PageHandle memPage$)$;

extern RC readLastBlock $($SM$\_$FileHandle $*$fHandle$,$ SM$\_$PageHandle memPage$)$;

$/*$ writing blocks to a page file $*/$

extern RC writeBlock $($int pageNum, SM$\_$FileHandle $*$fHandle$,$ SM$\_$PageHandle memPage$)$;

extern RC writeCurrentBlock $($SM$\_$FileHandle $*$fHandle$,$ SM$\_$PageHandle memPage$)$;

extern RC appendEmptyBlock $($SM$\_$FileHandle $*$fHandle$)$;

extern RC ensureCapacity $($int number$0$fPages, SM$\_$FileHandle $*$fHandle$)$;

#endif