Source:NetHack 3.2.0/worm.c

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Below is the full text to worm.c from the source code of NetHack 3.2.0. To link to a particular line, write [[NetHack 3.2.0/worm.c#line123]], for example.

Warning! This is the source code from an old release. For the latest release, see Source code

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1.    /*	SCCS Id: @(#)worm.c	3.2	95/01/28	*/
2.    /* Copyright (c) Stichting Mathematisch Centrum, Amsterdam, 1985. */
3.    /* NetHack may be freely redistributed.  See license for details. */
4.    
5.    #include "hack.h"
6.    #include "lev.h"
7.    
8.    #define newseg()		(struct wseg *) alloc(sizeof(struct wseg))
9.    #define dealloc_seg(wseg)	free((genericptr_t) (wseg))
10.   
11.   /* worm segment structure */
12.   struct wseg {
13.       struct wseg *nseg;
14.       xchar  wx, wy;	/* the segment's position */
15.   };
16.   
17.   static void FDECL(toss_wsegs, (struct wseg *,BOOLEAN_P));
18.   static void FDECL(shrink_worm, (int));
19.   static void FDECL(random_dir, (XCHAR_P,XCHAR_P,xchar *,xchar *));
20.   static struct wseg *FDECL(create_worm_tail, (int));
21.   
22.   /*  Description of long worm implementation.
23.    *
24.    *  Each monst struct of the head of a tailed worm has a wormno set to
25.    *			1 <= wormno < MAX_NUM_WORMS
26.    *  If wormno == 0 this does not mean that the monster is not a worm,
27.    *  it just means that the monster does not have a long worm tail.
28.    *
29.    *  The actual segments of a worm are not full blown monst structs.
30.    *  They are small wseg structs, and their position in the levels.monsters[][]
31.    *  array is held by the monst struct of the head of the worm.  This makes
32.    *  things like probing and hit point bookkeeping much easier.
33.    *
34.    *  The segments of the long worms on a level are kept as an array of
35.    *  singly threaded linked lists.  The wormno variable is used as an index
36.    *  for these segment arrays.
37.    *
38.    *  wtails:	The first (starting struct) of a linked list.  This points
39.    *		to the tail (last) segment of the worm.
40.    *
41.    *  wheads:	The last (end) of a linked list of segments.  This points to
42.    *		the segment that is at the same position as the real monster
43.    *		(the head).  Note that the segment that wheads[wormno] points
44.    *		to, is not displayed.  It is simply there to keep track of
45.    *		where the head came from, so that worm movement and display are
46.    *		simplified later.
47.    *		Keeping the head segment of the worm at the end of the list
48.    *		of tail segments is an endless source of confusion, but it is
49.    *		necessary.
50.    *		From now on, we will use "start" and "end" to refer to the
51.    *		linked list and "head" and "tail" to refer to the worm.
52.    *
53.    *  One final worm array is:
54.    *
55.    *  wgrowtime:	This tells us when to add another segment to the worm.
56.    *
57.    *  When a worm is moved, we add a new segment at the head, and delete the
58.    *  segment at the tail (unless we want it to grow).  This new head segment is
59.    *  located in the same square as the actual head of the worm.  If we want
60.    *  to grow the worm, we don't delete the tail segment, and we give the worm
61.    *  extra hit points, which possibly go into its maximum.
62.    *
63.    *  Non-moving worms (worm_nomove) are assumed to be surrounded by their own
64.    *  tail, and, thus, shrink instead of grow (as their tails keep going while
65.    *  their heads are stopped short).  In this case, we delete the last tail
66.    *  segment, and remove hit points from the worm.
67.    */
68.   
69.   struct wseg *wheads[MAX_NUM_WORMS]   = DUMMY, *wtails[MAX_NUM_WORMS] = DUMMY;
70.   long	    wgrowtime[MAX_NUM_WORMS] = DUMMY;
71.   
72.   /*
73.    *  get_wormno()
74.    *
75.    *  Find an unused worm tail slot and return the index.  A zero means that
76.    *  there are no slots available.  This means that the worm head can exist,
77.    *  it just cannot ever grow a tail.
78.    *
79.    *  It, also, means that there is an optimisation to made.  The [0] positions
80.    *  of the arrays are never used.  Meaning, we really *could* have one more
81.    *  tailed worm on the level, or use a smaller array (using wormno - 1).
82.    *
83.    *  Implementation is left to the interested hacker.
84.    */
85.   int
86.   get_wormno()
87.   {
88.       register int new_wormno = 1;
89.   
90.       while (new_wormno < MAX_NUM_WORMS) {
91.   	if (!wheads[new_wormno])
92.   	    return new_wormno; /* found an empty wtails[] slot at new_wormno */
93.   	new_wormno++;
94.       }
95.   
96.       return(0);	/* level infested with worms */
97.   }
98.   
99.   /*
100.   *  initworm()
101.   *
102.   *  Use if (mon->wormno = get_wormno()) before calling this function!
103.   *
104.   *  Initialize the worm entry.  This will set up the worm grow time, and
105.   *  create and initialize the dummy segment for wheads[] and wtails[].
106.   *
107.   *  If the worm has no tail (ie get_wormno() fails) then this function need
108.   *  not be called.
109.   */
110.  void
111.  initworm(worm, wseg_count)
112.      struct monst *worm;
113.      int wseg_count;
114.  {
115.      register struct wseg *seg, *new_tail = create_worm_tail(wseg_count);
116.      register int wnum = worm->wormno;
117.  
118.  /*  if (!wnum) return; /* bullet proofing */
119.  
120.      if (new_tail) {
121.  	wtails[wnum] = new_tail;
122.  	for (seg = new_tail; seg->nseg; seg = seg->nseg);
123.  	wheads[wnum] = seg;
124.      } else {
125.  	wtails[wnum] = wheads[wnum] = seg = newseg();
126.  	seg->nseg    = (struct wseg *) 0;
127.  	seg->wx      = worm->mx;
128.  	seg->wy      = worm->my;
129.      }
130.      wgrowtime[wnum] = 0L;
131.  }
132.  
133.  
134.  /*
135.   *  toss_wsegs()
136.   *
137.   *  Get rid of all worm segments on and following the given pointer curr.
138.   *  The display may or may not need to be updated as we free the segments.
139.   */
140.  static
141.  void
142.  toss_wsegs(curr, display_update)
143.      register struct wseg *curr;
144.      register boolean display_update;
145.  {
146.      register struct wseg *seg;
147.  
148.      while (curr) {
149.  	seg = curr->nseg;
150.  
151.  	/* remove from level.monsters[][] */
152.  
153.  	/* need to check curr->wx for genocided while migrating_mon */
154.  	if (curr->wx) {
155.  	    remove_monster(curr->wx, curr->wy);
156.  
157.  	    /* update screen before deallocation */
158.  	    if (display_update) newsym(curr->wx,curr->wy);
159.  	}
160.  
161.  	/* free memory used by the segment */
162.  	dealloc_seg(curr);
163.  	curr = seg;
164.      }
165.  }
166.  
167.  
168.  /*
169.   *  shrink_worm()
170.   *
171.   *  Remove the tail segment of the worm (the starting segment of the list).
172.   */
173.  static
174.  void
175.  shrink_worm(wnum)
176.      int wnum;	/* worm number */
177.  {
178.      struct wseg *seg;
179.  
180.      if (wtails[wnum] == wheads[wnum]) return;	/* no tail */
181.  
182.      seg = wtails[wnum];
183.      wtails[wnum] = seg->nseg;
184.      seg->nseg = (struct wseg *) 0;
185.      toss_wsegs(seg, TRUE);
186.  }
187.  
188.  /*
189.   *  worm_move()
190.   *
191.   *  Check for mon->wormno before calling this function!
192.   *
193.   *  Move the worm.  Maybe grow.
194.   */
195.  void
196.  worm_move(worm)
197.      struct monst *worm;
198.  {
199.      register struct wseg *seg, *new_seg;	/* new segment */
200.      register int	 wnum = worm->wormno;	/* worm number */
201.  
202.  
203.  /*  if (!wnum) return; /* bullet proofing */
204.  
205.      /*
206.       *  Place a segment at the old worm head.  The head has already moved.
207.       */
208.      seg = wheads[wnum];
209.      place_worm_seg(worm, seg->wx, seg->wy);
210.      newsym(seg->wx,seg->wy);		/* display the new segment */
211.  
212.      /*
213.       *  Create a new dummy segment head and place it at the end of the list.
214.       */
215.      new_seg       = newseg();
216.      new_seg->wx   = worm->mx;
217.      new_seg->wy   = worm->my;
218.      new_seg->nseg = (struct wseg *) 0;
219.      seg->nseg     = new_seg;		/* attach it to the end of the list */
220.      wheads[wnum]  = new_seg;		/* move the end pointer */
221.  
222.  
223.      if (wgrowtime[wnum] <= moves) {
224.  	if (!wgrowtime[wnum])
225.  	    wgrowtime[wnum] = moves + rnd(5);
226.  	else
227.  	    wgrowtime[wnum] += rn1(15, 3);
228.  	worm->mhp += 3;
229.  	if (worm->mhp > MHPMAX) worm->mhp = MHPMAX;
230.  	if (worm->mhp > worm->mhpmax) worm->mhpmax = worm->mhp;
231.      } else
232.  	/* The worm doesn't grow, so the last segment goes away. */
233.  	shrink_worm(wnum);
234.  }
235.  
236.  /*
237.   *  worm_nomove()
238.   *
239.   *  Check for mon->wormno before calling this function!
240.   *
241.   *  The worm don't move so it should shrink.
242.   */
243.  void
244.  worm_nomove(worm)
245.      register struct monst *worm;
246.  {
247.      shrink_worm((int) worm->wormno);	/* shrink */
248.  
249.      if (worm->mhp > 3)
250.  	worm->mhp -= 3;		/* mhpmax not changed ! */
251.      else
252.  	worm->mhp = 1;
253.  }
254.  
255.  /*
256.   *  wormgone()
257.   *
258.   *  Check for mon->wormno before calling this function!
259.   *
260.   *  Kill a worm tail.
261.   */
262.  void
263.  wormgone(worm)
264.      register struct monst *worm;
265.  {
266.      register int wnum = worm->wormno;
267.  
268.  /*  if (!wnum) return; /* bullet proofing */
269.  
270.      worm->wormno = 0;
271.  
272.      /*  This will also remove the real monster (ie 'w') from the its
273.       *  position in level.monsters[][].
274.       */
275.      toss_wsegs(wtails[wnum], TRUE);
276.  
277.      wheads[wnum] = wtails[wnum] = (struct wseg *) 0;
278.  }
279.  
280.  /*
281.   *  wormhitu()
282.   *
283.   *  Check for mon->wormno before calling this function!
284.   *
285.   *  If the hero is near any part of the worm, the worm will try to attack.
286.   */
287.  void
288.  wormhitu(worm)
289.      register struct monst *worm;
290.  {
291.      register int wnum = worm->wormno;
292.      register struct wseg *seg;
293.  
294.  /*  if (!wnum) return; /* bullet proofing */
295.  
296.  /*  This does not work right now because mattacku() thinks that the head is
297.   *  out of range of the player.  We might try to kludge, and bring the head
298.   *  within range for a tiny moment, but this needs a bit more looking at
299.   *  before we decide to do this.
300.   */
301.      for (seg = wtails[wnum]; seg; seg = seg->nseg)
302.  	if (distu(seg->wx, seg->wy) < 3)
303.  	    (void) mattacku(worm);
304.  }
305.  
306.  /*  cutworm()
307.   *
308.   *  Check for mon->wormno before calling this function!
309.   *
310.   *  When hitting a worm (worm) at position x, y, with a weapon (weap),
311.   *  there is a chance that the worm will be cut in half, and a chance
312.   *  that both halves will survive.
313.   */
314.  void
315.  cutworm(worm, x, y, weap)
316.      struct monst *worm;
317.      xchar x,y;
318.      struct obj *weap;
319.  {
320.      register struct wseg  *curr, *new_tail;
321.      register struct monst *new_worm;
322.      int wnum = worm->wormno;
323.      int cut_chance, new_wnum;
324.  
325.      if (!wnum) return; /* bullet proofing */
326.  
327.      if (x == worm->mx && y == worm->my) return;		/* hit on head */
328.  
329.      /* cutting goes best with a bladed weapon */
330.      cut_chance = rnd(20);	/* Normally  1-16 does not cut */
331.  				/* Normally 17-20 does */
332.  
333.      if (weap && is_blade(weap))	/* With a blade 1- 6 does not cut */
334.  	cut_chance += 10;	/*		7-20 does */
335.  
336.      if (cut_chance < 17) return;	/* not good enough */
337.  
338.      /* Find the segment that was attacked. */
339.      curr = wtails[wnum];
340.  
341.      while ( (curr->wx != x) || (curr->wy != y) ) {
342.  	curr = curr->nseg;
343.  	if (!curr) {
344.  	    impossible("cut_worm:  no segment at (%d,%d)", (int) x, (int) y);
345.  	    return;
346.  	}
347.      }
348.  
349.      /* If this is the tail segment, then the worm just loses it. */
350.      if (curr == wtails[wnum]) {
351.  	shrink_worm(wnum);
352.  	return;
353.      }
354.  
355.      /*
356.       *  Split the worm.  The tail for the new worm is the old worm's tail.
357.       *  The tail for the old worm is the segment that follows "curr",
358.       *  and "curr" becomes the dummy segment under the new head.
359.       */
360.      new_tail = wtails[wnum];
361.      wtails[wnum] = curr->nseg;
362.      curr->nseg = (struct wseg *) 0;	/* split the worm */
363.  
364.      /*
365.       *  At this point, the old worm is correct.  Any new worm will have
366.       *  it's head at "curr" and its tail at "new_tail".
367.       */
368.  
369.      /* Sometimes the tail end dies. */
370.      if (rn2(3) || !(new_wnum = get_wormno())) {
371.  	You("cut part of the tail off of %s.", mon_nam(worm));
372.  	toss_wsegs(new_tail, TRUE);
373.  	if (worm->mhp > 1) worm->mhp /= 2;
374.  	return;
375.      }
376.  
377.      /* Create the second worm. */
378.      new_worm  = newmonst(0);
379.      *new_worm = *worm;			/* make a copy of the old worm */
380.      new_worm->m_id = flags.ident++;	/* make sure it has a unique id */
381.      new_worm->wormno = new_wnum;	/* affix new worm number */
382.  
383.      if (worm->mtame)
384.  	new_worm->mtame = (rn2(max(2 + u.uluck, 2)) ? worm->mtame : 0);
385.      else
386.  	if (worm->mpeaceful)
387.  	    new_worm->mpeaceful = (rn2(max(2 + u.uluck, 2)) ? 1 : 0);
388.      set_malign(new_worm);
389.  
390.      new_worm->mxlth = new_worm->mnamelth = 0;
391.  
392.      /* Devalue the monster level of both halves of the worm. */
393.      worm->m_lev = ((unsigned)worm->m_lev <= 3) ?
394.  		   (unsigned)worm->m_lev : max((unsigned)worm->m_lev - 2, 3);
395.      new_worm->m_lev = worm->m_lev;
396.  
397.      /* Calculate the mhp on the new_worm for the (lower) monster level. */
398.      new_worm->mhpmax = new_worm->mhp = d((int)new_worm->m_lev, 8);
399.  
400.      /* Calculate the mhp on the old worm for the (lower) monster level. */
401.      if (worm->m_lev > 3) {
402.  	worm->mhpmax = d((int)worm->m_lev, 8);
403.  	if (worm->mhpmax < worm->mhp) worm->mhp = worm->mhpmax;
404.      }
405.  
406.      /* Add new monster to mon chain. */
407.      new_worm->nmon = fmon;
408.      fmon = new_worm;
409.  
410.      /* Initialize the new worm. */
411.      place_monster(new_worm, x, y);	/* put worm in level.monsters[][] */
412.      newsym(x, y);			/* make sure new worm shows up */
413.  
414.      wtails[new_wnum] = new_tail;	/* We've got all the info right now */
415.      wheads[new_wnum] = curr;		/* so we can do this faster than    */
416.      wgrowtime[new_wnum] = 0L;		/* trying to call initworm().       */
417.  
418.      /* Place the new monster at all the segment locations. */
419.      place_wsegs(new_worm);
420.  
421.  #if 0	/* long worms don't glow in the dark... */
422.      if (emits_light(worm->data))
423.  	new_light_source(new_worm->mx, new_worm->my,
424.  			 emits_light(worm->data),
425.  			 LS_MONSTER, (genericptr_t)new_worm);
426.  #endif
427.  
428.      You("cut %s in half.", mon_nam(worm));
429.  }
430.  
431.  
432.  /*
433.   *  see_wsegs()
434.   *
435.   *  Refresh all of the segments of the given worm.  This is only called
436.   *  from see_monster() in display.c or when a monster goes minvis.  It
437.   *  is located here for modularity.
438.   */
439.  void
440.  see_wsegs(worm)
441.      struct monst *worm;
442.  {
443.      struct wseg *curr = wtails[worm->wormno];
444.  
445.  /*  if (!mtmp->wormno) return; /* bullet proofing */
446.  
447.      while (curr != wheads[worm->wormno]) {
448.  	newsym(curr->wx,curr->wy);
449.  	curr = curr->nseg;
450.      }
451.  }
452.  
453.  
454.  /*
455.   *  save_worm()
456.   *
457.   *  Save the worm information for later use.  The count is the number
458.   *  of segments, including the dummy.  Called from save.c.
459.   */
460.  void
461.  save_worm(fd, mode)
462.      int fd, mode;
463.  {
464.      int i;
465.      int count;
466.      struct wseg *curr, *temp;
467.  
468.      if (perform_bwrite(mode)) {
469.  	for (i = 1; i < MAX_NUM_WORMS; i++) {
470.  	    for (count = 0, curr = wtails[i]; curr; curr = curr->nseg) count++;
471.  	    /* Save number of segments */
472.  	    bwrite(fd, (genericptr_t) &count, sizeof(int));
473.  	    /* Save segment locations of the monster. */
474.  	    if (count) {
475.  		for (curr = wtails[i]; curr; curr = curr->nseg) {
476.  		    bwrite(fd, (genericptr_t) &(curr->wx), sizeof(xchar));
477.  		    bwrite(fd, (genericptr_t) &(curr->wy), sizeof(xchar));
478.  		}
479.  	    }
480.  	}
481.  	bwrite(fd, (genericptr_t) wgrowtime, sizeof(wgrowtime));
482.      }
483.  
484.      if (release_data(mode)) {
485.  	/* Free the segments only.  savemonchn() will take care of the
486.  	 * monsters. */
487.  	for (i = 1; i < MAX_NUM_WORMS; i++) {
488.  	    if (!(curr = wtails[i])) continue;
489.  
490.  	    while (curr) {
491.  		temp = curr->nseg;
492.  		dealloc_seg(curr);		/* free the segment */
493.  		curr = temp;
494.  	    }
495.  	    wheads[i] = wtails[i] = (struct wseg *) 0;
496.  	}
497.      }
498.  
499.  }
500.  
501.  /*
502.   *  rest_worm()
503.   *
504.   *  Restore the worm information from the save file.  Called from restore.c
505.   */
506.  void
507.  rest_worm(fd)
508.      int fd;
509.  {
510.      int i, j, count;
511.      struct wseg *curr, *temp;
512.  
513.      for (i = 1; i < MAX_NUM_WORMS; i++) {
514.  	mread(fd, (genericptr_t) &count, sizeof(int));
515.  	if (!count) continue;	/* none */
516.  
517.  	/* Get the segments. */
518.  	for (curr = (struct wseg *) 0, j = 0; j < count; j++) {
519.  	    temp = newseg();
520.  	    temp->nseg = (struct wseg *) 0;
521.  	    mread(fd, (genericptr_t) &(temp->wx), sizeof(xchar));
522.  	    mread(fd, (genericptr_t) &(temp->wy), sizeof(xchar));
523.  	    if (curr)
524.  		curr->nseg = temp;
525.  	    else
526.  		wtails[i] = temp;
527.  	    curr = temp;
528.  	}
529.  	wheads[i] = curr;
530.      }
531.      mread(fd, (genericptr_t) wgrowtime, sizeof(wgrowtime));
532.  }
533.  
534.  /*
535.   *  place_wsegs()
536.   *
537.   *  Place the segments of the given worm.  Called from restore.c
538.   */
539.  void
540.  place_wsegs(worm)
541.      struct monst *worm;
542.  {
543.      struct wseg *curr = wtails[worm->wormno];
544.  
545.  /*  if (!mtmp->wormno) return; /* bullet proofing */
546.  
547.      while (curr != wheads[worm->wormno]) {
548.  	place_worm_seg(worm,curr->wx,curr->wy);
549.  	curr = curr->nseg;
550.      }
551.  }
552.  
553.  /*
554.   *  remove_worm()
555.   *
556.   *  This function is equivalent to the remove_monster #define in
557.   *  rm.h, only it will take the worm *and* tail out of the levels array.
558.   *  It does not get rid of (dealloc) the worm tail structures, and it does
559.   *  not remove the mon from the fmon chain.
560.   */
561.  void
562.  remove_worm(worm)
563.      register struct monst *worm;
564.  {
565.      register struct wseg *curr = wtails[worm->wormno];
566.  
567.  /*  if (!mtmp->wormno) return; /* bullet proofing */
568.  
569.      while (curr) {
570.  	remove_monster(curr->wx, curr->wy);
571.  	newsym(curr->wx, curr->wy);
572.  	curr = curr->nseg;
573.      }
574.  }
575.  
576.  /*
577.   *  place_worm_tail_randomly()
578.   *
579.   *  Place a worm tail somewhere on a level behind the head.
580.   *  This routine essentially reverses the order of the wsegs from head
581.   *  to tail while placing them.
582.   *  x, and y are most likely the worm->mx, and worm->my, but don't *need* to
583.   *  be, if somehow the head is disjoint from the tail.
584.   */
585.  void
586.  place_worm_tail_randomly(worm, x, y)
587.      struct monst *worm;
588.      xchar x, y;
589.  {
590.      int wnum = worm->wormno;
591.      struct wseg *curr = wtails[wnum];
592.      struct wseg *new_tail;
593.      register xchar ox = x, oy = y;
594.  
595.  /*  if (!wnum) return; /* bullet proofing */
596.  
597.      if (wnum && (!wtails[wnum] || !wheads[wnum]) ) {
598.  	impossible("place_worm_tail_randomly: wormno is set without a tail!");
599.  	return;
600.      }
601.  
602.      wheads[wnum] = new_tail = curr;
603.      curr = curr->nseg;
604.      new_tail->nseg = (struct wseg *) 0;
605.      new_tail->wx = x;
606.      new_tail->wy = y;
607.  
608.      while(curr)  {
609.  	xchar nx, ny;
610.  	char tryct = 0;
611.  
612.  	/* pick a random direction from x, y and search for goodpos() */
613.  
614.  	do {
615.  	    random_dir(ox, oy, &nx, &ny);
616.  	} while (!goodpos(nx, ny, worm, worm->data) && (tryct++ < 50));
617.  
618.  	if (tryct < 50)  {
619.  	    place_worm_seg(worm, nx, ny);
620.  	    curr->wx = ox = nx;
621.  	    curr->wy = oy = ny;
622.  	    wtails[wnum] = curr;
623.  	    curr = curr->nseg;
624.  	    wtails[wnum]->nseg = new_tail;
625.  	    new_tail = wtails[wnum];
626.  	    newsym(nx, ny);
627.  	} else {			/* Oops.  Truncate because there was */
628.  	    toss_wsegs(curr, FALSE);    /* no place for the rest of it */
629.  	    curr = (struct wseg *) 0;
630.  	}
631.      }
632.  }
633.  
634.  /*
635.   * Given a coordinate x, y.
636.   * return in *nx, *ny, the coordinates of one of the <= 8 squares adjoining.
637.   *
638.   * This function, and the loop it serves, could be eliminated by coding
639.   * enexto() with a search radius.
640.   */
641.  static
642.  void
643.  random_dir(x, y, nx, ny)
644.      register xchar   x,   y;
645.      register xchar *nx, *ny;
646.  {
647.      *nx = x;
648.      *ny = y;
649.  
650.      *nx += (x > 1 ?			/* extreme left ? */
651.  		(x < COLNO ?		 /* extreme right ? */
652.  			(rn2(3) - 1)	  /* neither so +1, 0, or -1 */
653.  		:	-rn2(2))	 /* 0, or -1 */
654.  	   :	rn2(2));		/* 0, or 1 */
655.  
656.      *ny += (*nx == x ?			/* same kind of thing with y */
657.  		(y > 1 ?
658.  		    (y < ROWNO ?
659.  			(rn2(2) ?
660.  			    1
661.  			:   -1)
662.  		    :	-1)
663.  		:   1)
664.  	    :	(y > 1 ?
665.  		    (y < ROWNO ?
666.  			(rn2(3) - 1)
667.  		    :	-rn2(2))
668.  		:   rn2(2)));
669.  }
670.  
671.  /*  count_wsegs()
672.   *
673.   *  returns
674.   *  the number of visible segments that a worm has.
675.   */
676.  
677.  int
678.  count_wsegs(mtmp)
679.      struct monst *mtmp;
680.  {
681.      register int i=0;
682.      register struct wseg *curr = (wtails[mtmp->wormno])->nseg;
683.  
684.  /*  if (!mtmp->wormno) return 0; /* bullet proofing */
685.  
686.      while (curr) {
687.  	i++;
688.  	curr = curr->nseg;
689.      }
690.  
691.      return i;
692.  }
693.  
694.  /*  create_worm_tail()
695.   *
696.   *  will create a worm tail chain of (num_segs + 1) and return a pointer to it.
697.   */
698.  static
699.  struct wseg *
700.  create_worm_tail(num_segs)
701.      int num_segs;
702.  {
703.      register int i=0;
704.      register struct wseg *new_tail, *curr;
705.  
706.      if (!num_segs) return (struct wseg *)0;
707.  
708.      new_tail = curr = newseg();
709.      curr->nseg = (struct wseg *)0;
710.      curr->wx = 0;
711.      curr->wy = 0;
712.  
713.      while (i < num_segs) {
714.  	curr->nseg = newseg();
715.  	curr = curr->nseg;
716.  	curr->nseg = (struct wseg *)0;
717.  	curr->wx = 0;
718.  	curr->wy = 0;
719.  	i++;
720.      }
721.  
722.      return (new_tail);
723.  }
724.  
725.  /*  worm_known()
726.   *
727.   *  Is any segment of this worm in viewing range?  Note: caller must check
728.   *  invisibility and telepathy (which should only show the head anyway).
729.   *  Mostly used in the canseemon() macro.
730.   */
731.  boolean
732.  worm_known(worm)
733.  struct monst *worm;
734.  {
735.      struct wseg *curr = (wtails[worm->wormno])->nseg;
736.  
737.      while (curr) {
738.  	if(cansee(curr->wx,curr->wy)) return TRUE;
739.  	curr = curr->nseg;
740.      }
741.      return FALSE;
742.  }
743.  
744.  /*worm.c*/