bitmap.h

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#ifndef _IPXE_BITMAP_H
#define _IPXE_BITMAP_H
 
/** @file
 *
 * Bitmaps for multicast downloads
 *
 */
 
FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
FILE_SECBOOT ( PERMITTED );
 
#include <stdint.h>
#include <stddef.h>
#include <stdlib.h>
 
/** A single block of bits within a bitmap */
typedef unsigned long bitmap_block_t;
 
/** Size of a block of bits (in bits) */
#define BITMAP_BLKSIZE ( sizeof ( bitmap_block_t ) * 8 )
 
/**
 * Block index within bitmap
 *
 * @v bit               Bit index
 * @ret index           Block index
 */
#define BITMAP_INDEX( bit ) ( (bit) / BITMAP_BLKSIZE )
 
/**
 * Block mask within bitmap
 *
 * @v bit               Bit index
 * @ret mask            Block mask
 */
#define BITMAP_MASK( bit ) ( 1UL << ( (bit) % BITMAP_BLKSIZE ) )
 
/**
 * Number of blocks in the bitmap
 *
 * @v length            Length of the bitmap, in bits
 * @ret blocks          Number of blocks
 */
#define BITMAP_BLOCKS( length ) ( ( (length) / BITMAP_BLKSIZE ) +       \
                                  ( !! ( (length) % BITMAP_BLKSIZE ) ) )
 
/** A bitmap */
struct bitmap {
        /** Bitmap data */
        bitmap_block_t *blocks;
        /** Length of the bitmap, in bits */
        unsigned int length;
        /** Index of first gap in the bitmap */
        unsigned int first_gap;
};
 
extern int bitmap_resize ( struct bitmap *bitmap, unsigned int new_length );
extern int bitmap_test ( struct bitmap *bitmap, unsigned int bit );
extern int bitmap_set ( struct bitmap *bitmap, unsigned int bit );
 
/**
 * Free bitmap resources
 *
 * @v bitmap            Bitmap
 */
static inline void bitmap_free ( struct bitmap *bitmap ) {
        free ( bitmap->blocks );
}
 
/**
 * Get first gap within bitmap
 *
 * @v bitmap            Bitmap
 * @ret first_gap       First gap
 *
 * The first gap is the first unset bit within the bitmap.
 */
static inline unsigned int bitmap_first_gap ( struct bitmap *bitmap ) {
        return bitmap->first_gap;
}
 
/**
 * Check to see if bitmap is full
 *
 * @v bitmap            Bitmap
 * @ret is_full         Bitmap is full
 *
 * The bitmap is full if it has no gaps (i.e. no unset bits).
 */
static inline int bitmap_full ( struct bitmap *bitmap ) {
        return ( bitmap->first_gap == bitmap->length );
}
 
#endif /* _IPXE_BITMAP_H */