1 /*
2 * Copyright (C) 2007 Michael Brown <mbrown@fensystems.co.uk>.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License as
6 * published by the Free Software Foundation; either version 2 of the
7 * License, or any later version.
8 *
9 * This program is distributed in the hope that it will be useful, but
10 * WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
17 */
18
19 FILE_LICENCE ( GPL2_OR_LATER );
20
21 #include <errno.h>
22 #include <gpxe/bitmap.h>
23
24 /** @file
25 *
26 * Bitmaps for multicast downloads
27 *
28 */
29
30 /**
31 * Resize bitmap
32 *
33 * @v bitmap Bitmap
34 * @v new_length New length of bitmap, in bits
35 * @ret rc Return status code
36 */
bitmap_resize(struct bitmap * bitmap,unsigned int new_length)37 int bitmap_resize ( struct bitmap *bitmap, unsigned int new_length ) {
38 unsigned int old_num_blocks;
39 unsigned int new_num_blocks;
40 size_t new_size;
41 bitmap_block_t *new_blocks;
42
43 old_num_blocks = BITMAP_INDEX ( bitmap->length + BITMAP_BLKSIZE - 1 );
44 new_num_blocks = BITMAP_INDEX ( new_length + BITMAP_BLKSIZE - 1 );
45
46 if ( old_num_blocks != new_num_blocks ) {
47 new_size = ( new_num_blocks * sizeof ( bitmap->blocks[0] ) );
48 new_blocks = realloc ( bitmap->blocks, new_size );
49 if ( ! new_blocks ) {
50 DBGC ( bitmap, "Bitmap %p could not resize to %d "
51 "bits\n", bitmap, new_length );
52 return -ENOMEM;
53 }
54 bitmap->blocks = new_blocks;
55 }
56 bitmap->length = new_length;
57
58 while ( old_num_blocks < new_num_blocks ) {
59 bitmap->blocks[old_num_blocks++] = 0;
60 }
61
62 DBGC ( bitmap, "Bitmap %p resized to %d bits\n", bitmap, new_length );
63 return 0;
64 }
65
66 /**
67 * Test bit in bitmap
68 *
69 * @v bitmap Bitmap
70 * @v bit Bit index
71 * @ret is_set Bit is set
72 */
bitmap_test(struct bitmap * bitmap,unsigned int bit)73 int bitmap_test ( struct bitmap *bitmap, unsigned int bit ) {
74 unsigned int index = BITMAP_INDEX ( bit );
75 bitmap_block_t mask = BITMAP_MASK ( bit );
76
77 if ( bit >= bitmap->length )
78 return 0;
79 return ( bitmap->blocks[index] & mask );
80 }
81
82 /**
83 * Set bit in bitmap
84 *
85 * @v bitmap Bitmap
86 * @v bit Bit index
87 */
bitmap_set(struct bitmap * bitmap,unsigned int bit)88 void bitmap_set ( struct bitmap *bitmap, unsigned int bit ) {
89 unsigned int index = BITMAP_INDEX ( bit );
90 bitmap_block_t mask = BITMAP_MASK ( bit );
91
92 DBGC ( bitmap, "Bitmap %p setting bit %d\n", bitmap, bit );
93
94 /* Update bitmap */
95 bitmap->blocks[index] |= mask;
96
97 /* Update first gap counter */
98 while ( bitmap_test ( bitmap, bitmap->first_gap ) ) {
99 bitmap->first_gap++;
100 }
101 }
102