1/*
2
3/usr/src/ext2ed/blockbitmap_com.c
4
5A part of the extended file system 2 disk editor.
6
7-------------------------
8Handles the block bitmap.
9-------------------------
10
11This file implements the commands which are specific to the blockbitmap type.
12
13First written on: July 5 1995
14
15Copyright (C) 1995 Gadi Oxman
16
17*/
18
19#include <stdio.h>
20#include <stdlib.h>
21#include <string.h>
22
23#include "ext2ed.h"
24
25/*
26
27The functions in this file use the flobal structure block_bitmap_info. This structure contains the current
28position in the bitmap.
29
30*/
31
32void type_ext2_block_bitmap___entry (char *command_line)
33
34/*
35
36This function changes the current entry in the bitmap. It just changes the entry_num variable in block_bitmap_info
37and dispatches a show command to show the new entry.
38
39*/
40
41{
42	unsigned long entry_num;
43	char *ptr,buffer [80];
44
45
46
47	ptr=parse_word (command_line,buffer);					/* Get the requested entry */
48	if (*ptr==0) {
49		wprintw (command_win,"Error - No argument specified\n");
50		refresh_command_win ();	return;
51	}
52	ptr=parse_word (ptr,buffer);
53
54	entry_num=atol (buffer);
55
56
57	if (entry_num >= file_system_info.super_block.s_blocks_per_group) {	/* Check if it is a valid entry number */
58
59		wprintw (command_win,"Error - Entry number out of bounds\n");
60		refresh_command_win ();return;
61	}
62
63
64
65	block_bitmap_info.entry_num=entry_num;					/* If it is, just change entry_num and */
66	strcpy (buffer,"show");dispatch (buffer);				/* dispatch a show command */
67}
68
69void type_ext2_block_bitmap___next (char *command_line)
70
71/*
72
73This function passes to the next entry in the bitmap. We just call the above entry command.
74
75*/
76
77{
78	long entry_offset=1;
79	char *ptr,buffer [80];
80
81	ptr=parse_word (command_line,buffer);
82	if (*ptr!=0) {
83		ptr=parse_word (ptr,buffer);
84		entry_offset=atol (buffer);
85	}
86
87	sprintf (buffer,"entry %ld",block_bitmap_info.entry_num+entry_offset);
88	dispatch (buffer);
89}
90
91void type_ext2_block_bitmap___prev (char *command_line)
92
93{
94	long entry_offset=1;
95	char *ptr,buffer [80];
96
97	ptr=parse_word (command_line,buffer);
98	if (*ptr!=0) {
99		ptr=parse_word (ptr,buffer);
100		entry_offset=atol (buffer);
101	}
102
103	sprintf (buffer,"entry %ld",block_bitmap_info.entry_num-entry_offset);
104	dispatch (buffer);
105}
106
107void type_ext2_block_bitmap___allocate (char *command_line)
108
109/*
110
111This function starts allocating block from the current position. Allocating involves setting the correct bits
112in the bitmap. This function is a vector version of allocate_block below - We just run on the blocks that
113we need to allocate, and call allocate_block for each one.
114
115*/
116
117{
118	long entry_num,num=1;
119	char *ptr,buffer [80];
120
121	ptr=parse_word (command_line,buffer);					/* Get the number of blocks to allocate */
122	if (*ptr!=0) {
123		ptr=parse_word (ptr,buffer);
124		num=atol (buffer);
125	}
126
127	entry_num=block_bitmap_info.entry_num;
128										/* Check for limits */
129	if (num > file_system_info.super_block.s_blocks_per_group-entry_num) {
130		wprintw (command_win,"Error - There aren't that much blocks in the group\n");
131		refresh_command_win ();return;
132	}
133
134	while (num) {								/* And call allocate_block */
135		allocate_block (entry_num);					/* for each block */
136		num--;entry_num++;
137	}
138
139	dispatch ("show");							/* Show the result */
140}
141
142void type_ext2_block_bitmap___deallocate (char *command_line)
143
144/* This is the opposite of the above function - We call deallocate_block instead of allocate_block */
145
146{
147	long entry_num,num=1;
148	char *ptr,buffer [80];
149
150	ptr=parse_word (command_line,buffer);
151	if (*ptr!=0) {
152		ptr=parse_word (ptr,buffer);
153		num=atol (buffer);
154	}
155
156	entry_num=block_bitmap_info.entry_num;
157	if (num > file_system_info.super_block.s_blocks_per_group-entry_num) {
158		wprintw (command_win,"Error - There aren't that much blocks in the group\n");
159		refresh_command_win ();return;
160	}
161
162	while (num) {
163		deallocate_block (entry_num);
164		num--;entry_num++;
165	}
166
167	dispatch ("show");
168}
169
170
171void allocate_block (long entry_num)
172
173/* In this function we convert the bit number into the right byte and inner bit positions. */
174
175{
176	unsigned char bit_mask=1;
177	int byte_offset,j;
178
179	byte_offset=entry_num/8;					/* Find the correct byte - entry_num/8 */
180									/* The position inside the byte is entry_num %8 */
181	for (j=0;j<entry_num%8;j++)
182		bit_mask*=2;						/* Generate the or mask - 1 at the right place */
183	type_data.u.buffer [byte_offset] |= bit_mask;			/* And apply it */
184}
185
186void deallocate_block (long entry_num)
187
188/* This is the opposite of allocate_block above. We use an and mask instead of an or mask. */
189
190{
191	unsigned char bit_mask=1;
192	int byte_offset,j;
193
194	byte_offset=entry_num/8;
195	for (j=0;j<entry_num%8;j++)
196		bit_mask*=2;
197	bit_mask^=0xff;
198
199	type_data.u.buffer [byte_offset] &= bit_mask;
200}
201
202void type_ext2_block_bitmap___show (char *command_line)
203
204/*
205
206We show the bitmap as a series of bits, grouped at 8-bit intervals. We display 8 such groups on each line.
207The current position (as known from block_bitmap_info.entry_num) is highlighted.
208
209*/
210
211{
212	int i,j;
213	unsigned char *ptr;
214	unsigned long block_num,entry_num;
215
216	ptr=type_data.u.buffer;
217	show_pad_info.line=0;show_pad_info.max_line=-1;
218
219	wmove (show_pad,0,0);
220	for (i=0,entry_num=0;i<file_system_info.super_block.s_blocks_per_group/8;i++,ptr++) {
221		for (j=1;j<=128;j*=2) {						/* j contains the and bit mask */
222			if (entry_num==block_bitmap_info.entry_num) {		/* Highlight the current entry */
223				wattrset (show_pad,A_REVERSE);
224				show_pad_info.line=show_pad_info.max_line-show_pad_info.display_lines/2;
225			}
226
227			if ((*ptr) & j)						/* Apply the mask */
228				wprintw (show_pad,"1");
229			else
230				wprintw (show_pad,"0");
231
232			if (entry_num==block_bitmap_info.entry_num)
233				wattrset (show_pad,A_NORMAL);
234
235			entry_num++;						/* Pass to the next entry */
236		}
237		wprintw (show_pad," ");
238		if (i%8==7) {							/* Display 8 groups in a row */
239			wprintw (show_pad,"\n");
240			show_pad_info.max_line++;
241		}
242	}
243
244	refresh_show_pad ();
245	show_info ();								/* Show the usual information */
246
247										/* Show the group number */
248	wmove (show_win,1,0);
249	wprintw (show_win,"Block bitmap of block group %ld\n",block_bitmap_info.group_num);
250										/* Show the block number */
251
252	block_num=block_bitmap_info.entry_num+block_bitmap_info.group_num*file_system_info.super_block.s_blocks_per_group;
253	block_num+=file_system_info.super_block.s_first_data_block;
254
255	wprintw (show_win,"Status of block %ld - ",block_num);			/* and the allocation status */
256	ptr=type_data.u.buffer+block_bitmap_info.entry_num/8;
257	j=1;
258	for (i=block_bitmap_info.entry_num % 8;i>0;i--)
259		j*=2;
260	if ((*ptr) & j)
261		wprintw (show_win,"Allocated\n");
262	else
263		wprintw (show_win,"Free\n");
264	refresh_show_win ();
265}
266