#include<stdio.
h>
#include<stdlib.h>
#include<string.h>
struct File_details
{
char file_name[10];
int file_size;
int file_start;
int file_end;
}directory[100];
int bit_vector[100];
int memory_size;
int free_blocks;
int count = 0;
void initialize_bit_vector()
{
int i;
printf("Enter number of memory blocks : ");
scanf("%d",&memory_size);
for(i=0 ; i < memory_size ; i++)
{
bit_vector[i] = -1;
}
free_blocks = memory_size;
}
void show_memory_blocks()
{
int i;
for(i=0 ; i < memory_size ; i++)
{
printf("%d\t",bit_vector[i]);
}
printf("\nFree blocks : %d",free_blocks);
}
int find_free_block()
{
int i;
int block_index[memory_size];
int block_count = 0;
int random;
for(i=0 ; i<memory_size ; i++)
{
if(bit_vector[i] == -1)
{
block_index[block_count++] = i;
}
}
if(block_count == 0)
return -1;
else
{
random=rand() % block_count;
return block_index[random];
}
}
void update_bit_vector(int index , int value)
{
bit_vector[index] = value;
}
void add_directory_entry(char *filename , int filesize ,int start_pos , int
end_pos)
{
strcpy(directory[count].file_name , filename);
directory[count].file_size = filesize;
directory[count].file_start = start_pos;
directory[count].file_end = end_pos;
count++;
}
void create_file()
{
char filename[10];
int filesize;
int start_pos , prev_pos , next_pos;
int i;
printf("Enter file name to create : ");
scanf("%s",filename);
printf("Enter file size : ");
scanf("%d",&filesize);
if(filesize > free_blocks)
{
printf("\nNo free memory !");
}
start_pos = find_free_block();
if(start_pos == -1)
{
printf("\nNo free memory !");
}
else
{
prev_pos = start_pos;
update_bit_vector(prev_pos , -2);
}
for (i = 0; i < filesize; i++)
{
if (i == filesize - 1)
{
update_bit_vector(prev_pos, -9);
}
else
{
next_pos = find_free_block();
if (next_pos == -1)
{
printf("No free memory !\n");
return;
}
update_bit_vector(prev_pos, next_pos);
prev_pos = next_pos;
update_bit_vector(prev_pos, -2);
}
}
add_directory_entry(filename, filesize, start_pos, prev_pos);
free_blocks = free_blocks - filesize;
printf("File created: %s, Size: %d, Start: %d, End: %d\n",
filename, filesize, start_pos, prev_pos);
}
void delete_file()
{
char filename[10];
int start_pos, next_pos;
int i, j, temp;
int file_found = 0;
printf("Enter file name to delete: ");
scanf("%s", filename);
for (i = 0; i < count; i++)
{
if (strcmp(directory[i].file_name, filename) == 0)
{
file_found = 1;
start_pos = directory[i].file_start;
next_pos = start_pos;
while (next_pos != -9)
{
temp = next_pos;
next_pos = bit_vector[temp];
update_bit_vector(temp, -1);
free_blocks++;
}
for (j = i; j < count - 1; j++)
{
directory[j] = directory[j + 1];
}
count--;
printf("File deleted\n");
break;
}
}
if (!file_found) {
printf("File not found\n");
}
}
void display_directory()
{
int i;
for(i = 0 ; i < count ; i++)
{
printf("\nName: %s , Size : %d , Start : %d , End : %d",
directory[i].file_name ,directory[i].file_size , directory[i].file_start ,
directory[i].file_end);
}
}
int main()
{
int choice;
initialize_bit_vector();
do
{
printf("\n\n1. Show Memory Blocks\n");
printf("2. Create New File\n");
printf("3. Show Directory\n");
printf("4. Delete File\n");
printf("5. Exit\n");
printf("\nEnter choice: ");
scanf("%d", &choice);
switch (choice)
{
case 1: show_memory_blocks(); break;
case 2: create_file(); break;
case 3: display_directory(); break;
case 4: delete_file(); break;
case 5: printf("You chose to Exit !"); break;
default: printf("Invalid Choice\n");
}
}while(choice !=5);
}
