libsimdb/src/bitmap.h

#ifndef HAS_BITMAP_H
#define HAS_BITMAP_H 1

/**
 * @file
 * @brief Functions for work with image bitmaps
 */

/** Bits per bitmap side (currently - 16) */
#define SIMDB_BITMAP_SIDE 16
/** Bitmap size in bytes (currently - 32) */
#define SIMDB_BITMAP_SIZE (SIMDB_BITMAP_SIDE * (SIMDB_BITMAP_SIDE / 8))
/** Total bits in bitmap (currently - 256) */
#define SIMDB_BITMAP_BITS (SIMDB_BITMAP_SIZE * 8)

/** placeholders for various bit states */
#define CHAR_USED '@' /**< bit is 1 */
#define CHAR_NONE '-' /**< bit is 0 */

/**
 * @brief Compare two bitmaps
 * @param a First bitmap to compare
 * @param b Second bitmap to compare
 * @returns Integer showing difference between bitmaps in bits (0-256)
 */
int
simdb_bitmap_compare(const unsigned char *a,
                     const unsigned char *b);

/**
 * @brief Make difference map of to bitmaps
 * @param a    First bitmap to compare
 * @param b    Second bitmap to compare
 * @param diff Storage for difference map
 * @returns Size of generated map (now is @a BITMAP_SIZE)
 */
size_t
simdb_bitmap_diffmap(const unsigned char *a,
                     const unsigned char *b,
                     unsigned char *diff);


/**
 * @brief Unpack BITmap to BYTEmap
 * @param map Source bitmap
 * @param buf Pointer to store generated bytemap
 * @returns Size of generated bytemap (now is @a BITMAP_BITS)
 */
size_t
simdb_bitmap_unpack(const unsigned char *map,
                    unsigned char ** const buf);

/**
 * @brief Print bitmap to stdout as ascii-square
 * @param map Source bitmap
 * @note Height of "square" is equals to BITMAP_SIDE,
 *   but width is BITMAP_SIDE x 2, for ease of reading
 */
void
simdb_bitmap_print(const unsigned char *map);
#endif