xref: /original-bsd/games/tetris/screen.c (revision b4971bb3)
1 /*-
2  * Copyright (c) 1992, 1993
3  *	The Regents of the University of California.  All rights reserved.
4  *
5  * This code is derived from software contributed to Berkeley by
6  * Chris Torek and Darren F. Provine.
7  *
8  * %sccs.include.redist.c%
9  *
10  *	@(#)screen.c	8.1 (Berkeley) 05/31/93
11  */
12 
13 /*
14  * Tetris screen control.
15  */
16 
17 #include <sgtty.h>
18 #include <sys/ioctl.h>
19 
20 #include <setjmp.h>
21 #include <signal.h>
22 #include <stdio.h>
23 #include <stdlib.h>
24 #include <string.h>
25 #include <unistd.h>
26 
27 #ifndef sigmask
28 #define sigmask(s) (1 << ((s) - 1))
29 #endif
30 
31 #include "screen.h"
32 #include "tetris.h"
33 
34 /*
35  * XXX - need a <termcap.h>
36  */
37 int	tgetent __P((char *, const char *));
38 int	tgetflag __P((const char *));
39 int	tgetnum __P((const char *));
40 int	tputs __P((const char *, int, int (*)(int)));
41 
42 static cell curscreen[B_SIZE];	/* 1 => standout (or otherwise marked) */
43 static int curscore;
44 static int isset;		/* true => terminal is in game mode */
45 static struct sgttyb oldtt;
46 static void (*tstp)();
47 
48 char	*tgetstr(), *tgoto();
49 
50 
51 /*
52  * Capabilities from TERMCAP.
53  */
54 char	PC, *BC, *UP;		/* tgoto requires globals: ugh! */
55 short	ospeed;
56 
57 static char
58 	*bcstr,			/* backspace char */
59 	*CEstr,			/* clear to end of line */
60 	*CLstr,			/* clear screen */
61 	*CMstr,			/* cursor motion string */
62 #ifdef unneeded
63 	*CRstr,			/* "\r" equivalent */
64 #endif
65 	*HOstr,			/* cursor home */
66 	*LLstr,			/* last line, first column */
67 	*pcstr,			/* pad character */
68 	*TEstr,			/* end cursor motion mode */
69 	*TIstr;			/* begin cursor motion mode */
70 char
71 	*SEstr,			/* end standout mode */
72 	*SOstr;			/* begin standout mode */
73 static int
74 	COnum,			/* co# value */
75 	LInum,			/* li# value */
76 	MSflag;			/* can move in standout mode */
77 
78 
79 struct tcsinfo {	/* termcap string info; some abbrevs above */
80 	char tcname[3];
81 	char **tcaddr;
82 } tcstrings[] = {
83 	"bc", &bcstr,
84 	"ce", &CEstr,
85 	"cl", &CLstr,
86 	"cm", &CMstr,
87 #ifdef unneeded
88 	"cr", &CRstr,
89 #endif
90 	"le", &BC,		/* move cursor left one space */
91 	"pc", &pcstr,
92 	"se", &SEstr,
93 	"so", &SOstr,
94 	"te", &TEstr,
95 	"ti", &TIstr,
96 	"up", &UP,		/* cursor up */
97 	0
98 };
99 
100 /* This is where we will actually stuff the information */
101 
102 static char combuf[1024], tbuf[1024];
103 
104 
105 /*
106  * Routine used by tputs().
107  */
108 int
109 put(c)
110 	int c;
111 {
112 
113 	return (putchar(c));
114 }
115 
116 /*
117  * putstr() is for unpadded strings (either as in termcap(5) or
118  * simply literal strings); putpad() is for padded strings with
119  * count=1.  (See screen.h for putpad().)
120  */
121 #define	putstr(s)	(void)fputs(s, stdout)
122 #define	moveto(r, c)	putpad(tgoto(CMstr, c, r))
123 
124 /*
125  * Set up from termcap.
126  */
127 void
128 scr_init()
129 {
130 	static int bsflag, xsflag, sgnum;
131 #ifdef unneeded
132 	static int ncflag;
133 #endif
134 	char *term, *fill;
135 	static struct tcninfo {	/* termcap numeric and flag info */
136 		char tcname[3];
137 		int *tcaddr;
138 	} tcflags[] = {
139 		"bs", &bsflag,
140 		"ms", &MSflag,
141 #ifdef unneeded
142 		"nc", &ncflag,
143 #endif
144 		"xs", &xsflag,
145 		0
146 	}, tcnums[] = {
147 		"co", &COnum,
148 		"li", &LInum,
149 		"sg", &sgnum,
150 		0
151 	};
152 
153 	if ((term = getenv("TERM")) == NULL)
154 		stop("you must set the TERM environment variable");
155 	if (tgetent(tbuf, term) <= 0)
156 		stop("cannot find your termcap");
157 	fill = combuf;
158 	{
159 		register struct tcsinfo *p;
160 
161 		for (p = tcstrings; p->tcaddr; p++)
162 			*p->tcaddr = tgetstr(p->tcname, &fill);
163 	}
164 	{
165 		register struct tcninfo *p;
166 
167 		for (p = tcflags; p->tcaddr; p++)
168 			*p->tcaddr = tgetflag(p->tcname);
169 		for (p = tcnums; p->tcaddr; p++)
170 			*p->tcaddr = tgetnum(p->tcname);
171 	}
172 	if (bsflag)
173 		BC = "\b";
174 	else if (BC == NULL && bcstr != NULL)
175 		BC = bcstr;
176 	if (CLstr == NULL)
177 		stop("cannot clear screen");
178 	if (CMstr == NULL || UP == NULL || BC == NULL)
179 		stop("cannot do random cursor positioning via tgoto()");
180 	PC = pcstr ? *pcstr : 0;
181 	if (sgnum >= 0 || xsflag)
182 		SOstr = SEstr = NULL;
183 #ifdef unneeded
184 	if (ncflag)
185 		CRstr = NULL;
186 	else if (CRstr == NULL)
187 		CRstr = "\r";
188 #endif
189 }
190 
191 /* this foolery is needed to modify tty state `atomically' */
192 static jmp_buf scr_onstop;
193 
194 #define	sigunblock(mask) sigsetmask(sigblock(0) & ~(mask))
195 
196 static void
197 stopset(sig)
198 	int sig;
199 {
200 	(void) signal(sig, SIG_DFL);
201 	(void) kill(getpid(), sig);
202 	(void) sigunblock(sigmask(sig));
203 	longjmp(scr_onstop, 1);
204 }
205 
206 static void
207 scr_stop()
208 {
209 	scr_end();
210 	(void) kill(getpid(), SIGTSTP);
211 	(void) sigunblock(sigmask(SIGTSTP));
212 	scr_set();
213 	scr_msg(key_msg, 1);
214 }
215 
216 /*
217  * Set up screen mode.
218  */
219 void
220 scr_set()
221 {
222 	struct winsize ws;
223 	struct sgttyb newtt;
224 	volatile int omask;
225 	void (*ttou)();
226 
227 	omask = sigblock(sigmask(SIGTSTP) | sigmask(SIGTTOU));
228 	if ((tstp = signal(SIGTSTP, stopset)) == SIG_IGN)
229 		(void) signal(SIGTSTP, SIG_IGN);
230 	if ((ttou = signal(SIGTSTP, stopset)) == SIG_IGN)
231 		(void) signal(SIGTSTP, SIG_IGN);
232 	/*
233 	 * At last, we are ready to modify the tty state.  If
234 	 * we stop while at it, stopset() above will longjmp back
235 	 * to the setjmp here and we will start over.
236 	 */
237 	(void) setjmp(scr_onstop);
238 	(void) sigsetmask(omask);
239 	Rows = 0, Cols = 0;
240 	if (ioctl(0, TIOCGWINSZ, &ws) == 0) {
241 		Rows = ws.ws_row;
242 		Cols = ws.ws_col;
243 	}
244 	if (Rows == 0)
245 		Rows = LInum;
246 	if (Cols == 0)
247 	Cols = COnum;
248 	if (Rows < MINROWS || Cols < MINCOLS) {
249 		(void) fprintf(stderr,
250 		    "the screen is too small: must be at least %d x %d",
251 		    MINROWS, MINCOLS);
252 		stop("");	/* stop() supplies \n */
253 	}
254 	if (ioctl(0, TIOCGETP, &oldtt))
255 		stop("ioctl(TIOCGETP) fails");
256 	newtt = oldtt;
257 	newtt.sg_flags = (newtt.sg_flags | CBREAK) & ~(CRMOD | ECHO);
258 	if ((newtt.sg_flags & TBDELAY) == XTABS)
259 		newtt.sg_flags &= ~TBDELAY;
260 	if (ioctl(0, TIOCSETN, &newtt))
261 		stop("ioctl(TIOCSETN) fails");
262 	ospeed = newtt.sg_ospeed;
263 	omask = sigblock(sigmask(SIGTSTP) | sigmask(SIGTTOU));
264 
265 	/*
266 	 * We made it.  We are now in screen mode, modulo TIstr
267 	 * (which we will fix immediately).
268 	 */
269 	if (TIstr)
270 		putstr(TIstr);	/* termcap(5) says this is not padded */
271 	if (tstp != SIG_IGN)
272 		(void) signal(SIGTSTP, scr_stop);
273 	(void) signal(SIGTTOU, ttou);
274 
275 	isset = 1;
276 	(void) sigsetmask(omask);
277 	scr_clear();
278 }
279 
280 /*
281  * End screen mode.
282  */
283 void
284 scr_end()
285 {
286 	int omask = sigblock(sigmask(SIGTSTP) | sigmask(SIGTTOU));
287 
288 	/* move cursor to last line */
289 	if (LLstr)
290 		putstr(LLstr);	/* termcap(5) says this is not padded */
291 	else
292 		moveto(Rows - 1, 0);
293 	/* exit screen mode */
294 	if (TEstr)
295 		putstr(TEstr);	/* termcap(5) says this is not padded */
296 	(void) fflush(stdout);
297 	(void) ioctl(0, TIOCSETN, &oldtt);
298 	isset = 0;
299 	/* restore signals */
300 	(void) signal(SIGTSTP, tstp);
301 	(void) sigsetmask(omask);
302 }
303 
304 void
305 stop(why)
306 	char *why;
307 {
308 
309 	if (isset)
310 		scr_end();
311 	(void) fprintf(stderr, "aborting: %s\n", why);
312 	exit(1);
313 }
314 
315 /*
316  * Clear the screen, forgetting the current contents in the process.
317  */
318 void
319 scr_clear()
320 {
321 
322 	putpad(CLstr);
323 	curscore = -1;
324 	bzero((char *)curscreen, sizeof(curscreen));
325 }
326 
327 #if vax && !__GNUC__
328 typedef int regcell;	/* pcc is bad at `register char', etc */
329 #else
330 typedef cell regcell;
331 #endif
332 
333 /*
334  * Update the screen.
335  */
336 void
337 scr_update()
338 {
339 	register cell *bp, *sp;
340 	register regcell so, cur_so = 0;
341 	register int i, ccol, j;
342 	int omask = sigblock(sigmask(SIGTSTP));
343 
344 	/* always leave cursor after last displayed point */
345 	curscreen[D_LAST * B_COLS - 1] = -1;
346 
347 	if (score != curscore) {
348 		if (HOstr)
349 			putpad(HOstr);
350 		else
351 			moveto(0, 0);
352 		(void) printf("%d", score);
353 		curscore = score;
354 	}
355 
356 	bp = &board[D_FIRST * B_COLS];
357 	sp = &curscreen[D_FIRST * B_COLS];
358 	for (j = D_FIRST; j < D_LAST; j++) {
359 		ccol = -1;
360 		for (i = 0; i < B_COLS; bp++, sp++, i++) {
361 			if (*sp == (so = *bp))
362 				continue;
363 			*sp = so;
364 			if (i != ccol) {
365 				if (cur_so && MSflag) {
366 					putpad(SEstr);
367 					cur_so = 0;
368 				}
369 				moveto(RTOD(j), CTOD(i));
370 			}
371 			if (SOstr) {
372 				if (so != cur_so) {
373 					putpad(so ? SOstr : SEstr);
374 					cur_so = so;
375 				}
376 				putstr("  ");
377 			} else
378 				putstr(so ? "XX" : "  ");
379 			ccol = i + 1;
380 			/*
381 			 * Look ahead a bit, to avoid extra motion if
382 			 * we will be redrawing the cell after the next.
383 			 * Motion probably takes four or more characters,
384 			 * so we save even if we rewrite two cells
385 			 * `unnecessarily'.  Skip it all, though, if
386 			 * the next cell is a different color.
387 			 */
388 #define	STOP (B_COLS - 3)
389 			if (i > STOP || sp[1] != bp[1] || so != bp[1])
390 				continue;
391 			if (sp[2] != bp[2])
392 				sp[1] = -1;
393 			else if (i < STOP && so == bp[2] && sp[3] != bp[3]) {
394 				sp[2] = -1;
395 				sp[1] = -1;
396 			}
397 		}
398 	}
399 	if (cur_so)
400 		putpad(SEstr);
401 	(void) fflush(stdout);
402 	(void) sigsetmask(omask);
403 }
404 
405 /*
406  * Write a message (set!=0), or clear the same message (set==0).
407  * (We need its length in case we have to overwrite with blanks.)
408  */
409 void
410 scr_msg(s, set)
411 	register char *s;
412 	int set;
413 {
414 
415 	if (set || CEstr == NULL) {
416 		register int l = strlen(s);
417 
418 		moveto(Rows - 2, ((Cols - l) >> 1) - 1);
419 		if (set)
420 			putstr(s);
421 		else
422 			while (--l >= 0)
423 				(void) putchar(' ');
424 	} else {
425 		moveto(Rows - 2, 0);
426 		putpad(CEstr);
427 	}
428 }
429