#ifndef _UTIL_H_e07286a3_
#define _UTIL_H_e07286a3_

/*
 * APIs exported by util.c.  Assorted utility routines that didn't seem
 *  to me to fall into other categories.
 */

#include "structs.h"

/*
 * Always returns false, and has the calling signature of an object ops
 *  `collapsible' function.
 */
extern int never_collapsible(OBJ *, OBJ *);

/*
 * Always returns false, and has the calling signature of an object ops
 *  `identical' function.
 */
extern int never_identical(OBJ *, OBJ *);

/*
 * Returns the square of the (Euclidean) distance between two cells on
 *  the same level.  This knows about LVF_WRAPAROUND.  This panics if
 *  handed LOCs that aren't on the same level.
 */
extern int distance2(LOC *, LOC *);

/*
 * Returns the L-infinity distance between two cells on the same level,
 *  that is, the larger of the difference in X coordinates and the
 *  difference in Y coordinates.  This knows about LVF_WRAPAROUND.
 *  This panics if handed LOCs that aren't on the same level.
 */
extern int distancei(LOC *, LOC *);

/*
 * Return true iff the argument is a vowel.  This is specific to ASCII
 *  and English...but so is much of the rest of the game.
 */
extern int vowel(char);

/*
 * movecell(c,dx,dy,wrap) moves a distance (dx,dy) from c, returning
 *  the cell reached.  If wrap is true or if the level has
 *  LVF_WRAPAROUND set, the delta can wrap.  Panics if asked to move
 *  off the edge of a level when not wrapping.
 */
extern LOC *movecell(LOC *, int, int, int);

/*
 * dirkey(key,dxp,dyp,dxyp,oflagsp,iflags) takes key as a motion
 *  command (one of hjklyubn, possibly uppercase or control-modified)
 *  and some flags.  iflags can include zero or more of DK_NOCTL and
 *  DK_NOCAPS; these suppress recognition of, respectively,
 *  control-modified and uppercase motion commands.  If key is a valid
 *  motion command, taking iflags into account, then up to four things
 *  are written through the remaining arguments: the corresponding X
 *  delta through dxp, the Y delta through dyp, both deltas as an XY
 *  through dxyp, and a flags value with 0, DK_CTL, or DK_CAPS through
 *  oflagsp.  If any of these last four are nil, that write is skipped.
 */
extern int dirkey(int, int *, int *, XY *, int *, int);
#define DK_CTL    0x00000001
#define DK_CAPS   0x00000002
#define DK_NOCTL  0x00000004
#define DK_NOCAPS 0x00000008

/*
 * These take an (X,Y) delta and rotate it clockwise 90° (turn_r),
 *  counterclockwise 90° (turn_l), clockwise 45° (turn_r45), or
 *  counterclockwise 45° (turn_l45).  The 45° turns, of course, switch
 *  between both-coordinate steps and single-coordinate steps, meaning
 *  their Euclidean length switches betwen 1 and sqrt(2).
 */
extern XY turn_r(XY);
extern XY turn_l(XY);
extern XY turn_r45(XY);
extern XY turn_l45(XY);

/*
 * This returns its second or third argument depending on whether the
 *  monster is the player avatar (second arg) or not (third arg).
 */
extern const char *pickverb(MONST *, const char *, const char *);

#endif