/*
/usr/src/ext2ed/blockbitmap_com.c
A part of the extended file system 2 disk editor.
-------------------------
Handles the block bitmap.
-------------------------
This file implements the commands which are specific to the blockbitmap type.
First written on: July 5 1995
Copyright (C) 1995 Gadi Oxman
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "ext2ed.h"
/*
The functions in this file use the flobal structure block_bitmap_info. This structure contains the current
position in the bitmap.
*/
void type_ext2_block_bitmap___entry (char *command_line)
/*
This function changes the current entry in the bitmap. It just changes the entry_num variable in block_bitmap_info
and dispatches a show command to show the new entry.
*/
{
unsigned long entry_num;
char *ptr,buffer [80];
ptr=parse_word (command_line,buffer); /* Get the requested entry */
if (*ptr==0) {
wprintw (command_win,"Error - No argument specified\n");
refresh_command_win (); return;
}
ptr=parse_word (ptr,buffer);
entry_num=atol (buffer);
if (entry_num >= file_system_info.super_block.s_blocks_per_group) { /* Check if it is a valid entry number */
wprintw (command_win,"Error - Entry number out of bounds\n");
refresh_command_win ();return;
}
block_bitmap_info.entry_num=entry_num; /* If it is, just change entry_num and */
strcpy (buffer,"show");dispatch (buffer); /* dispatch a show command */
}
void type_ext2_block_bitmap___next (char *command_line)
/*
This function passes to the next entry in the bitmap. We just call the above entry command.
*/
{
long entry_offset=1;
char *ptr,buffer [80];
ptr=parse_word (command_line,buffer);
if (*ptr!=0) {
ptr=parse_word (ptr,buffer);
entry_offset=atol (buffer);
}
sprintf (buffer,"entry %ld",block_bitmap_info.entry_num+entry_offset);
dispatch (buffer);
}
void type_ext2_block_bitmap___prev (char *command_line)
{
long entry_offset=1;
char *ptr,buffer [80];
ptr=parse_word (command_line,buffer);
if (*ptr!=0) {
ptr=parse_word (ptr,buffer);
entry_offset=atol (buffer);
}
sprintf (buffer,"entry %ld",block_bitmap_info.entry_num-entry_offset);
dispatch (buffer);
}
void type_ext2_block_bitmap___allocate (char *command_line)
/*
This function starts allocating block from the current position. Allocating involves setting the correct bits
in the bitmap. This function is a vector version of allocate_block below - We just run on the blocks that
we need to allocate, and call allocate_block for each one.
*/
{
long entry_num,num=1;
char *ptr,buffer [80];
ptr=parse_word (command_line,buffer); /* Get the number of blocks to allocate */
if (*ptr!=0) {
ptr=parse_word (ptr,buffer);
num=atol (buffer);
}
entry_num=block_bitmap_info.entry_num;
/* Check for limits */
if (num > file_system_info.super_block.s_blocks_per_group-entry_num) {
wprintw (command_win,"Error - There aren't that much blocks in the group\n");
refresh_command_win ();return;
}
while (num) { /* And call allocate_block */
allocate_block (entry_num); /* for each block */
num--;entry_num++;
}
dispatch ("show"); /* Show the result */
}
void type_ext2_block_bitmap___deallocate (char *command_line)
/* This is the opposite of the above function - We call deallocate_block instead of allocate_block */
{
long entry_num,num=1;
char *ptr,buffer [80];
ptr=parse_word (command_line,buffer);
if (*ptr!=0) {
ptr=parse_word (ptr,buffer);
num=atol (buffer);
}
entry_num=block_bitmap_info.entry_num;
if (num > file_system_info.super_block.s_blocks_per_group-entry_num) {
wprintw (command_win,"Error - There aren't that much blocks in the group\n");
refresh_command_win ();return;
}
while (num) {
deallocate_block (entry_num);
num--;entry_num++;
}
dispatch ("show");
}
void allocate_block (long entry_num)
/* In this function we convert the bit number into the right byte and inner bit positions. */
{
unsigned char bit_mask=1;
int byte_offset,j;
byte_offset=entry_num/8; /* Find the correct byte - entry_num/8 */
/* The position inside the byte is entry_num %8 */
for (j=0;j<entry_num%8;j++)
bit_mask*=2; /* Generate the or mask - 1 at the right place */
type_data.u.buffer [byte_offset] |= bit_mask; /* And apply it */
}
void deallocate_block (long entry_num)
/* This is the opposite of allocate_block above. We use an and mask instead of an or mask. */
{
unsigned char bit_mask=1;
int byte_offset,j;
byte_offset=entry_num/8;
for (j=0;j<entry_num%8;j++)
bit_mask*=2;
bit_mask^=0xff;
type_data.u.buffer [byte_offset] &= bit_mask;
}
void type_ext2_block_bitmap___show (char *command_line)
/*
We show the bitmap as a series of bits, grouped at 8-bit intervals. We display 8 such groups on each line.
The current position (as known from block_bitmap_info.entry_num) is highlighted.
*/
{
int i,j;
unsigned char *ptr;
unsigned long block_num,entry_num;
ptr=type_data.u.buffer;
show_pad_info.line=0;show_pad_info.max_line=-1;
wmove (show_pad,0,0);
for (i=0,entry_num=0;i<file_system_info.super_block.s_blocks_per_group/8;i++,ptr++) {
for (j=1;j<=128;j*=2) { /* j contains the and bit mask */
if (entry_num==block_bitmap_info.entry_num) { /* Highlight the current entry */
wattrset (show_pad,A_REVERSE);
show_pad_info.line=show_pad_info.max_line-show_pad_info.display_lines/2;
}
if ((*ptr) & j) /* Apply the mask */
wprintw (show_pad,"1");
else
wprintw (show_pad,"0");
if (entry_num==block_bitmap_info.entry_num)
wattrset (show_pad,A_NORMAL);
entry_num++; /* Pass to the next entry */
}
wprintw (show_pad," ");
if (i%8==7) { /* Display 8 groups in a row */
wprintw (show_pad,"\n");
show_pad_info.max_line++;
}
}
refresh_show_pad ();
show_info (); /* Show the usual information */
/* Show the group number */
wmove (show_win,1,0);
wprintw (show_win,"Block bitmap of block group %ld\n",block_bitmap_info.group_num);
/* Show the block number */
block_num=block_bitmap_info.entry_num+block_bitmap_info.group_num*file_system_info.super_block.s_blocks_per_group;
block_num+=file_system_info.super_block.s_first_data_block;
wprintw (show_win,"Status of block %ld - ",block_num); /* and the allocation status */
ptr=type_data.u.buffer+block_bitmap_info.entry_num/8;
j=1;
for (i=block_bitmap_info.entry_num % 8;i>0;i--)
j*=2;
if ((*ptr) & j)
wprintw (show_win,"Allocated\n");
else
wprintw (show_win,"Free\n");
refresh_show_win ();
}