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1.1 root 1: /* Cursor motion subroutines for GNU Emacs.
2: Copyright (C) 1985 Free Software Foundation, Inc.
3: based primarily on public domain code written by Chris Torek
4:
5: This file is part of GNU Emacs.
6:
7: GNU Emacs is free software; you can redistribute it and/or modify
8: it under the terms of the GNU General Public License as published by
9: the Free Software Foundation; either version 1, or (at your option)
10: any later version.
11:
12: GNU Emacs is distributed in the hope that it will be useful,
13: but WITHOUT ANY WARRANTY; without even the implied warranty of
14: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15: GNU General Public License for more details.
16:
17: You should have received a copy of the GNU General Public License
18: along with GNU Emacs; see the file COPYING. If not, write to
19: the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
20:
21:
22: #include "config.h"
23: #include <stdio.h>
24: #include "cm.h"
25: #include "termhooks.h"
26:
27: #define BIG 9999 /* 9999 good on VAXen. For 16 bit machines
28: use about 2000.... */
29:
30: char *tgoto ();
31:
32: extern char *BC, *UP;
33:
34: int cost; /* sums up costs */
35:
36: /* ARGSUSED */
37: evalcost (c)
38: char c;
39: {
40: cost++;
41: }
42:
43: void
44: cmputc (c)
45: char c;
46: {
47: if (termscript)
48: fputc (c & 0177, termscript);
49: putchar (c & 0177);
50: }
51:
52: /* NEXT TWO ARE DONE WITH MACROS */
53: #if 0
54: /*
55: * Assume the cursor is at row row, column col. Normally used only after
56: * clearing the screen, when the cursor is at (0, 0), but what the heck,
57: * let's let the guy put it anywhere.
58: */
59:
60: static
61: at (row, col) {
62: curY = row;
63: curX = col;
64: }
65:
66: /*
67: * Add n columns to the current cursor position.
68: */
69:
70: static
71: addcol (n) {
72: curX += n;
73:
74: /*
75: * If cursor hit edge of screen, what happened?
76: * N.B.: DO NOT!! write past edge of screen. If you do, you
77: * deserve what you get. Furthermore, on terminals with
78: * autowrap (but not magicwrap), don't write in the last column
79: * of the last line.
80: */
81:
82: if (curX == Wcm.cm_cols) {
83: /*
84: * Well, if magicwrap, still there, past the edge of the
85: * screen (!). If autowrap, on the col 0 of the next line.
86: * Otherwise on last column.
87: */
88:
89: if (Wcm.cm_magicwrap)
90: ; /* "limbo" */
91: else if (Wcm.cm_autowrap) {
92: curX = 0;
93: curY++; /* Beware end of screen! */
94: }
95: else
96: curX--;
97: }
98: }
99: #endif
100:
101: /*
102: * (Re)Initialize the cost factors, given the output speed of the terminal
103: * in the variable ospeed. (Note: this holds B300, B9600, etc -- ie stuff
104: * out of <sgtty.h>.)
105: */
106:
107: cmcostinit ()
108: {
109: char *p;
110:
111: #define COST(x,e) (x ? (cost = 0, tputs (x, 1, e), cost) : BIG)
112: #define CMCOST(x,e) ((x == 0) ? BIG : (p = tgoto(x, 0, 0), COST(p ,e)))
113:
114: Wcm.cc_up = COST (Wcm.cm_up, evalcost);
115: Wcm.cc_down = COST (Wcm.cm_down, evalcost);
116: Wcm.cc_left = COST (Wcm.cm_left, evalcost);
117: Wcm.cc_right = COST (Wcm.cm_right, evalcost);
118: Wcm.cc_home = COST (Wcm.cm_home, evalcost);
119: Wcm.cc_cr = COST (Wcm.cm_cr, evalcost);
120: Wcm.cc_ll = COST (Wcm.cm_ll, evalcost);
121: Wcm.cc_tab = Wcm.cm_tabwidth ? COST (Wcm.cm_tab, evalcost) : BIG;
122:
123: /*
124: * These last three are actually minimum costs. When (if) they are
125: * candidates for the least-cost motion, the real cost is computed.
126: * (Note that "0" is the assumed to generate the minimum cost.
127: * While this is not necessarily true, I have yet to see a terminal
128: * for which is not; all the terminals that have variable-cost
129: * cursor motion seem to take straight numeric values. --ACT)
130: */
131:
132: Wcm.cc_abs = CMCOST (Wcm.cm_abs, evalcost);
133: Wcm.cc_habs = CMCOST (Wcm.cm_habs, evalcost);
134: Wcm.cc_vabs = CMCOST (Wcm.cm_vabs, evalcost);
135:
136: #undef CMCOST
137: #undef COST
138: }
139:
140: /*
141: * Calculate the cost to move from (srcy, srcx) to (dsty, dstx) using
142: * up and down, and left and right, motions, and tabs. If doit is set
143: * actually perform the motion.
144: */
145:
146: static
147: calccost (srcy, srcx, dsty, dstx, doit)
148: {
149: register int deltay,
150: deltax,
151: c,
152: totalcost;
153: int ntabs,
154: n2tabs,
155: tabx,
156: tab2x,
157: tabcost;
158: register char *p;
159:
160: /* If have just wrapped on a terminal with xn,
161: don't believe the cursor position: give up here
162: and force use of absolute positioning. */
163:
164: if (curX == Wcm.cm_cols)
165: goto fail;
166:
167: totalcost = 0;
168: if ((deltay = dsty - srcy) == 0)
169: goto x;
170: if (deltay < 0)
171: p = Wcm.cm_up, c = Wcm.cc_up, deltay = -deltay;
172: else
173: p = Wcm.cm_down, c = Wcm.cc_down;
174: if (c == BIG) { /* caint get thar from here */
175: if (doit)
176: printf ("OOPS");
177: return c;
178: }
179: totalcost = c * deltay;
180: if (doit)
181: while (--deltay >= 0)
182: tputs (p, 1, cmputc);
183: x:
184: if ((deltax = dstx - srcx) == 0)
185: goto done;
186: if (deltax < 0) {
187: p = Wcm.cm_left, c = Wcm.cc_left, deltax = -deltax;
188: goto dodelta; /* skip all the tab junk */
189: }
190: /* Tabs (the toughie) */
191: if (Wcm.cc_tab >= BIG || !Wcm.cm_usetabs)
192: goto olddelta; /* forget it! */
193:
194: /*
195: * ntabs is # tabs towards but not past dstx; n2tabs is one more
196: * (ie past dstx), but this is only valid if that is not past the
197: * right edge of the screen. We can check that at the same time
198: * as we figure out where we would be if we use the tabs (which
199: * we will put into tabx (for ntabs) and tab2x (for n2tabs)).
200: */
201:
202: ntabs = (deltax + srcx % Wcm.cm_tabwidth) / Wcm.cm_tabwidth;
203: n2tabs = ntabs + 1;
204: tabx = (srcx / Wcm.cm_tabwidth + ntabs) * Wcm.cm_tabwidth;
205: tab2x = tabx + Wcm.cm_tabwidth;
206:
207: if (tab2x >= Wcm.cm_cols) /* too far (past edge) */
208: n2tabs = 0;
209:
210: /*
211: * Now set tabcost to the cost for using ntabs, and c to the cost
212: * for using n2tabs, then pick the minimum.
213: */
214:
215: /* cost for ntabs + cost for right motion */
216: tabcost = ntabs ? ntabs * Wcm.cc_tab + (dstx - tabx) * Wcm.cc_right
217: : BIG;
218:
219: /* cost for n2tabs + cost for left motion */
220: c = n2tabs ? n2tabs * Wcm.cc_tab + (tab2x - dstx) * Wcm.cc_left
221: : BIG;
222:
223: if (c < tabcost) /* then cheaper to overshoot & back up */
224: ntabs = n2tabs, tabcost = c, tabx = tab2x;
225:
226: if (tabcost >= BIG) /* caint use tabs */
227: goto newdelta;
228:
229: /*
230: * See if tabcost is less than just moving right
231: */
232:
233: if (tabcost < (deltax * Wcm.cc_right)) {
234: totalcost += tabcost; /* use the tabs */
235: if (doit)
236: while (--ntabs >= 0)
237: tputs (Wcm.cm_tab, 1, cmputc);
238: srcx = tabx;
239: }
240:
241: /*
242: * Now might as well just recompute the delta.
243: */
244:
245: newdelta:
246: if ((deltax = dstx - srcx) == 0)
247: goto done;
248: olddelta:
249: if (deltax > 0)
250: p = Wcm.cm_right, c = Wcm.cc_right;
251: else
252: p = Wcm.cm_left, c = Wcm.cc_left, deltax = -deltax;
253:
254: dodelta:
255: if (c == BIG) { /* caint get thar from here */
256: fail:
257: if (doit)
258: printf ("OOPS");
259: return BIG;
260: }
261: totalcost += c * deltax;
262: if (doit)
263: while (--deltax >= 0)
264: tputs (p, 1, cmputc);
265: done:
266: return totalcost;
267: }
268:
269: losecursor ()
270: {
271: curY = -1;
272: }
273:
274: #define USEREL 0
275: #define USEHOME 1
276: #define USELL 2
277: #define USECR 3
278:
279: cmgoto (row, col)
280: {
281: int homecost,
282: crcost,
283: llcost,
284: relcost,
285: directcost;
286: int use;
287: char *p,
288: *dcm;
289:
290: /* First the degenerate case */
291: if (row == curY && col == curX) /* already there */
292: return;
293:
294: if (curY >= 0 && curX >= 0)
295: {
296: /*
297: * Pick least-cost motions
298: */
299:
300: relcost = calccost (curY, curX, row, col, 0);
301: use = USEREL;
302: if ((homecost = Wcm.cc_home) < BIG)
303: homecost += calccost (0, 0, row, col, 0);
304: if (homecost < relcost)
305: relcost = homecost, use = USEHOME;
306: if ((llcost = Wcm.cc_ll) < BIG)
307: llcost += calccost (Wcm.cm_rows - 1, 0, row, col, 0);
308: if (llcost < relcost)
309: relcost = llcost, use = USELL;
310: if ((crcost = Wcm.cc_cr) < BIG) {
311: if (Wcm.cm_autolf)
312: if (curY + 1 >= Wcm.cm_rows)
313: crcost = BIG;
314: else
315: crcost += calccost (curY + 1, 0, row, col, 0);
316: else
317: crcost += calccost (curY, 0, row, col, 0);
318: }
319: if (crcost < relcost)
320: relcost = crcost, use = USECR;
321: directcost = Wcm.cc_abs, dcm = Wcm.cm_abs;
322: if (row == curY && Wcm.cc_habs < BIG)
323: directcost = Wcm.cc_habs, dcm = Wcm.cm_habs;
324: else if (col == curX && Wcm.cc_vabs < BIG)
325: directcost = Wcm.cc_vabs, dcm = Wcm.cm_vabs;
326: }
327: else
328: {
329: directcost = 0, relcost = 100000;
330: dcm = Wcm.cm_abs;
331: }
332:
333: /*
334: * In the following comparison, the = in <= is because when the costs
335: * are the same, it looks nicer (I think) to move directly there.
336: */
337: if (directcost <= relcost)
338: {
339: /* compute REAL direct cost */
340: cost = 0;
341: p = dcm == Wcm.cm_habs ? tgoto (dcm, row, col) :
342: tgoto (dcm, col, row);
343: tputs (p, 1, evalcost);
344: if (cost <= relcost)
345: { /* really is cheaper */
346: tputs (p, 1, cmputc);
347: curY = row, curX = col;
348: return;
349: }
350: }
351:
352: switch (use)
353: {
354: case USEHOME:
355: tputs (Wcm.cm_home, 1, cmputc);
356: curY = 0, curX = 0;
357: break;
358:
359: case USELL:
360: tputs (Wcm.cm_ll, 1, cmputc);
361: curY = Wcm.cm_rows - 1, curX = 0;
362: break;
363:
364: case USECR:
365: tputs (Wcm.cm_cr, 1, cmputc);
366: if (Wcm.cm_autolf)
367: curY++;
368: curX = 0;
369: break;
370: }
371:
372: (void) calccost (curY, curX, row, col, 1);
373: curY = row, curX = col;
374: }
375:
376: /* Clear out all terminal info.
377: Used before copying into it the info on the actual terminal.
378: */
379:
380: Wcm_clear ()
381: {
382: bzero (&Wcm, sizeof Wcm);
383: UP = 0;
384: BC = 0;
385: }
386:
387: /*
388: * Initialized stuff
389: * Return 0 if can do CM.
390: */
391:
392: Wcm_init ()
393: {
394: /* Check that we know the size of the screen.... */
395: if (Wcm.cm_rows <= 0 || Wcm.cm_cols <= 0)
396: return - 1;
397: if (Wcm.cm_abs && !Wcm.cm_ds)
398: return 0;
399: /* Require up and left, and, if no absolute, down and right */
400: if (!Wcm.cm_up || !Wcm.cm_left)
401: return - 1;
402: if (!Wcm.cm_abs && (!Wcm.cm_down || !Wcm.cm_right))
403: return - 1;
404: return 0;
405: }
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