1: /* Cursor motion subroutines for GNU Emacs.
    2:    Copyright (C) 1985, 1995, 2001, 2002, 2003, 2004,
    3:                  2005, 2006, 2007  Free Software Foundation, Inc.
    4:     based primarily on public domain code written by Chris Torek
    5: 
    6: This file is part of GNU Emacs.
    7: 
    8: GNU Emacs is free software; you can redistribute it and/or modify
    9: it under the terms of the GNU General Public License as published by
   10: the Free Software Foundation; either version 2, or (at your option)
   11: any later version.
   12: 
   13: GNU Emacs is distributed in the hope that it will be useful,
   14: but WITHOUT ANY WARRANTY; without even the implied warranty of
   15: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   16: GNU General Public License for more details.
   17: 
   18: You should have received a copy of the GNU General Public License
   19: along with GNU Emacs; see the file COPYING.  If not, write to
   20: the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
   21: Boston, MA 02110-1301, USA.  */
   22: 
   23: 
   24: #include <config.h>
   25: #include <stdio.h>
   26: #include "cm.h"
   27: #include "termhooks.h"
   28: 
   29: /* For now, don't try to include termcap.h.  On some systems,
   30:    configure finds a non-standard termcap.h that the main build
   31:    won't find.  */
   32: 
   33: #if defined HAVE_TERMCAP_H && 0
   34: #include <termcap.h>
   35: #else
   36: extern void tputs P_ ((const char *, int, int (*)(int)));
   37: extern char *tgoto P_ ((const char *, int, int));
   38: #endif
   39: 
   40: #define BIG     9999                /* 9999 good on VAXen.  For 16 bit machines
   41:                                    use about 2000.... */
   42: 
   43: extern char *BC, *UP;
   44: 
   45: int cost;               /* sums up costs */
   46: 
   47: /* ARGSUSED */
   48: int
   49: evalcost (c)
   50:      char c;
   51: {
   52:   cost++;
   53:   return c;
   54: }
   55: 
   56: int
   57: cmputc (c)
   58:      char c;
   59: {
   60:   if (termscript)
   61:     fputc (c & 0177, termscript);
   62:   putchar (c & 0177);
   63:   return c;
   64: }
   65: 
   66: /* NEXT TWO ARE DONE WITH MACROS */
   67: #if 0
   68: /*
   69:  * Assume the cursor is at row row, column col.  Normally used only after
   70:  * clearing the screen, when the cursor is at (0, 0), but what the heck,
   71:  * let's let the guy put it anywhere.
   72:  */
   73: 
   74: static
   75: at (row, col) {
   76:     curY = row;
   77:     curX = col;
   78: }
   79: 
   80: /*
   81:  * Add n columns to the current cursor position.
   82:  */
   83: 
   84: static
   85: addcol (n) {
   86:     curX += n;
   87: 
   88:     /*
   89:      * If cursor hit edge of screen, what happened?
   90:      * N.B.: DO NOT!! write past edge of screen.  If you do, you
   91:      * deserve what you get.  Furthermore, on terminals with
   92:      * autowrap (but not magicwrap), don't write in the last column
   93:      * of the last line.
   94:      */
   95: 
   96:     if (curX == Wcm.cm_cols) {
   97:         /*
   98:          * Well, if magicwrap, still there, past the edge of the
   99:          * screen (!).  If autowrap, on the col 0 of the next line.
  100:          * Otherwise on last column.
  101:          */
  102: 
  103:         if (Wcm.cm_magicwrap)
  104:             ;                  /* "limbo" */
  105:         else if (Wcm.cm_autowrap) {
  106:             curX = 0;
  107:             curY++;            /* Beware end of screen! */
  108:         }
  109:         else
  110:             curX--;
  111:     }
  112: }
  113: #endif
  114: 
  115: /*
  116:  * Terminals with magicwrap (xn) don't all behave identically.
  117:  * The VT100 leaves the cursor in the last column but will wrap before
  118:  * printing the next character.  I hear that the Concept terminal does
  119:  * the wrap immediately but ignores the next newline it sees.  And some
  120:  * terminals just have buggy firmware, and think that the cursor is still
  121:  * in limbo if we use direct cursor addressing from the phantom column.
  122:  * The only guaranteed safe thing to do is to emit a CRLF immediately
  123:  * after we reach the last column; this takes us to a known state.
  124:  */
  125: void
  126: cmcheckmagic ()
  127: {
  128:   if (curX == FrameCols)
  129:     {
  130:       if (!MagicWrap || curY >= FrameRows - 1)
  131:         abort ();
  132:       if (termscript)
  133:         putc ('\r', termscript);
  134:       putchar ('\r');
  135:       if (termscript)
  136:         putc ('\n', termscript);
  137:       putchar ('\n');
  138:       curX = 0;
  139:       curY++;
  140:     }
  141: }
  142: 
  143: 
  144: /*
  145:  * (Re)Initialize the cost factors, given the output speed of the terminal
  146:  * in the variable ospeed.  (Note: this holds B300, B9600, etc -- ie stuff
  147:  * out of <sgtty.h>.)
  148:  */
  149: 
  150: void
  151: cmcostinit ()
  152: {
  153:     char *p;
  154: 
  155: #define COST(x,e)       (x ? (cost = 0, tputs (x, 1, e), cost) : BIG)
  156: #define CMCOST(x,e)     ((x == 0) ? BIG : (p = tgoto(x, 0, 0), COST(p ,e)))
  157: 
  158:     Wcm.cc_up =         COST (Wcm.cm_up, evalcost);
  159:     Wcm.cc_down =       COST (Wcm.cm_down, evalcost);
  160:     Wcm.cc_left =       COST (Wcm.cm_left, evalcost);
  161:     Wcm.cc_right =      COST (Wcm.cm_right, evalcost);
  162:     Wcm.cc_home =       COST (Wcm.cm_home, evalcost);
  163:     Wcm.cc_cr =         COST (Wcm.cm_cr, evalcost);
  164:     Wcm.cc_ll =         COST (Wcm.cm_ll, evalcost);
  165:     Wcm.cc_tab =        Wcm.cm_tabwidth ? COST (Wcm.cm_tab, evalcost) : BIG;
  166: 
  167:     /*
  168:      * These last three are actually minimum costs.  When (if) they are
  169:      * candidates for the least-cost motion, the real cost is computed.
  170:      * (Note that "0" is the assumed to generate the minimum cost.
  171:      * While this is not necessarily true, I have yet to see a terminal
  172:      * for which is not; all the terminals that have variable-cost
  173:      * cursor motion seem to take straight numeric values.  --ACT)
  174:      */
  175: 
  176:     Wcm.cc_abs =  CMCOST (Wcm.cm_abs, evalcost);
  177:     Wcm.cc_habs = CMCOST (Wcm.cm_habs, evalcost);
  178:     Wcm.cc_vabs = CMCOST (Wcm.cm_vabs, evalcost);
  179: 
  180: #undef CMCOST
  181: #undef COST
  182: }
  183: 
  184: /*
  185:  * Calculate the cost to move from (srcy, srcx) to (dsty, dstx) using
  186:  * up and down, and left and right, motions, and tabs.  If doit is set
  187:  * actually perform the motion.
  188:  */
  189: 
  190: static int
  191: calccost (srcy, srcx, dsty, dstx, doit)
  192:      int srcy, srcx, dsty, dstx, doit;
  193: {
  194:     register int    deltay,
  195:                     deltax,
  196:                     c,
  197:                     totalcost;
  198:     int     ntabs,
  199:             n2tabs,
  200:             tabx,
  201:             tab2x,
  202:             tabcost;
  203:     register char  *p;
  204: 
  205:     /* If have just wrapped on a terminal with xn,
  206:        don't believe the cursor position: give up here
  207:        and force use of absolute positioning.  */
  208: 
  209:     if (curX == Wcm.cm_cols)
  210:       goto fail;
  211: 
  212:     totalcost = 0;
  213:     if ((deltay = dsty - srcy) == 0)
  214:         goto x;
  215:     if (deltay < 0)
  216:         p = Wcm.cm_up, c = Wcm.cc_up, deltay = -deltay;
  217:     else
  218:         p = Wcm.cm_down, c = Wcm.cc_down;
  219:     if (c == BIG) {             /* caint get thar from here */
  220:         if (doit)
  221:             printf ("OOPS");
  222:         return c;
  223:     }
  224:     totalcost = c * deltay;
  225:     if (doit)
  226:         while (--deltay >= 0)
  227:             tputs (p, 1, cmputc);
  228: x:
  229:     if ((deltax = dstx - srcx) == 0)
  230:         goto done;
  231:     if (deltax < 0) {
  232:         p = Wcm.cm_left, c = Wcm.cc_left, deltax = -deltax;
  233:         goto dodelta;          /* skip all the tab junk */
  234:     }
  235:     /* Tabs (the toughie) */
  236:     if (Wcm.cc_tab >= BIG || !Wcm.cm_usetabs)
  237:         goto olddelta;         /* forget it! */
  238: 
  239:     /*
  240:      * ntabs is # tabs towards but not past dstx; n2tabs is one more
  241:      * (ie past dstx), but this is only valid if that is not past the
  242:      * right edge of the screen.  We can check that at the same time
  243:      * as we figure out where we would be if we use the tabs (which
  244:      * we will put into tabx (for ntabs) and tab2x (for n2tabs)).
  245:      */
  246: 
  247:     ntabs = (deltax + srcx % Wcm.cm_tabwidth) / Wcm.cm_tabwidth;
  248:     n2tabs = ntabs + 1;
  249:     tabx = (srcx / Wcm.cm_tabwidth + ntabs) * Wcm.cm_tabwidth;
  250:     tab2x = tabx + Wcm.cm_tabwidth;
  251: 
  252:     if (tab2x >= Wcm.cm_cols)   /* too far (past edge) */
  253:         n2tabs = 0;
  254: 
  255:     /*
  256:      * Now set tabcost to the cost for using ntabs, and c to the cost
  257:      * for using n2tabs, then pick the minimum.
  258:      */
  259: 
  260:                    /* cost for ntabs     +    cost for right motion */
  261:     tabcost = ntabs ? ntabs * Wcm.cc_tab + (dstx - tabx) * Wcm.cc_right
  262:                     : BIG;
  263: 
  264:                    /* cost for n2tabs    +    cost for left motion */
  265:     c = n2tabs  ?    n2tabs * Wcm.cc_tab + (tab2x - dstx) * Wcm.cc_left
  266:                 : BIG;
  267: 
  268:     if (c < tabcost)            /* then cheaper to overshoot & back up */
  269:         ntabs = n2tabs, tabcost = c, tabx = tab2x;
  270: 
  271:     if (tabcost >= BIG)         /* caint use tabs */
  272:         goto newdelta;
  273: 
  274:     /*
  275:      * See if tabcost is less than just moving right
  276:      */
  277: 
  278:     if (tabcost < (deltax * Wcm.cc_right)) {
  279:         totalcost += tabcost;  /* use the tabs */
  280:         if (doit)
  281:             while (--ntabs >= 0)
  282:                 tputs (Wcm.cm_tab, 1, cmputc);
  283:         srcx = tabx;
  284:     }
  285: 
  286:     /*
  287:      * Now might as well just recompute the delta.
  288:      */
  289: 
  290: newdelta:
  291:     if ((deltax = dstx - srcx) == 0)
  292:         goto done;
  293: olddelta:
  294:     if (deltax > 0)
  295:         p = Wcm.cm_right, c = Wcm.cc_right;
  296:     else
  297:         p = Wcm.cm_left, c = Wcm.cc_left, deltax = -deltax;
  298: 
  299: dodelta:
  300:     if (c == BIG) {             /* caint get thar from here */
  301: fail:
  302:         if (doit)
  303:             printf ("OOPS");
  304:         return BIG;
  305:     }
  306:     totalcost += c * deltax;
  307:     if (doit)
  308:         while (--deltax >= 0)
  309:             tputs (p, 1, cmputc);
  310: done:
  311:     return totalcost;
  312: }
  313: 
  314: #if 0
  315: losecursor ()
  316: {
  317:   curY = -1;
  318: }
  319: #endif
  320: 
  321: #define USEREL  0
  322: #define USEHOME 1
  323: #define USELL   2
  324: #define USECR   3
  325: 
  326: void
  327: cmgoto (row, col)
  328:      int row, col;
  329: {
  330:     int     homecost,
  331:             crcost,
  332:             llcost,
  333:             relcost,
  334:             directcost;
  335:     int     use;
  336:     char   *p,
  337:            *dcm;
  338: 
  339:   /* First the degenerate case */
  340:   if (row == curY && col == curX) /* already there */
  341:     return;
  342: 
  343:   if (curY >= 0 && curX >= 0)
  344:     {
  345:       /* We may have quick ways to go to the upper-left, bottom-left,
  346:        * start-of-line, or start-of-next-line.  Or it might be best to
  347:        * start where we are.  Examine the options, and pick the cheapest.
  348:        */
  349: 
  350:       relcost = calccost (curY, curX, row, col, 0);
  351:       use = USEREL;
  352:       if ((homecost = Wcm.cc_home) < BIG)
  353:           homecost += calccost (0, 0, row, col, 0);
  354:       if (homecost < relcost)
  355:           relcost = homecost, use = USEHOME;
  356:       if ((llcost = Wcm.cc_ll) < BIG)
  357:           llcost += calccost (Wcm.cm_rows - 1, 0, row, col, 0);
  358:       if (llcost < relcost)
  359:           relcost = llcost, use = USELL;
  360:       if ((crcost = Wcm.cc_cr) < BIG) {
  361:           if (Wcm.cm_autolf)
  362:               if (curY + 1 >= Wcm.cm_rows)
  363:                   crcost = BIG;
  364:               else
  365:                   crcost += calccost (curY + 1, 0, row, col, 0);
  366:           else
  367:               crcost += calccost (curY, 0, row, col, 0);
  368:       }
  369:       if (crcost < relcost)
  370:           relcost = crcost, use = USECR;
  371:       directcost = Wcm.cc_abs, dcm = Wcm.cm_abs;
  372:       if (row == curY && Wcm.cc_habs < BIG)
  373:           directcost = Wcm.cc_habs, dcm = Wcm.cm_habs;
  374:       else if (col == curX && Wcm.cc_vabs < BIG)
  375:           directcost = Wcm.cc_vabs, dcm = Wcm.cm_vabs;
  376:     }
  377:   else
  378:     {
  379:       directcost = 0, relcost = 100000;
  380:       dcm = Wcm.cm_abs;
  381:     }
  382: 
  383:   /*
  384:    * In the following comparison, the = in <= is because when the costs
  385:    * are the same, it looks nicer (I think) to move directly there.
  386:    */
  387:   if (directcost <= relcost)
  388:     {
  389:       /* compute REAL direct cost */
  390:       cost = 0;
  391:       p = dcm == Wcm.cm_habs ? tgoto (dcm, row, col) :
  392:                                tgoto (dcm, col, row);
  393:       tputs (p, 1, evalcost);
  394:       if (cost <= relcost)
  395:         {      /* really is cheaper */
  396:           tputs (p, 1, cmputc);
  397:           curY = row, curX = col;
  398:           return;
  399:         }
  400:     }
  401: 
  402:   switch (use)
  403:     {
  404:     case USEHOME:
  405:       tputs (Wcm.cm_home, 1, cmputc);
  406:       curY = 0, curX = 0;
  407:       break;
  408: 
  409:     case USELL:
  410:       tputs (Wcm.cm_ll, 1, cmputc);
  411:       curY = Wcm.cm_rows - 1, curX = 0;
  412:       break;
  413: 
  414:     case USECR:
  415:       tputs (Wcm.cm_cr, 1, cmputc);
  416:       if (Wcm.cm_autolf)
  417:         curY++;
  418:       curX = 0;
  419:       break;
  420:     }
  421: 
  422:   (void) calccost (curY, curX, row, col, 1);
  423:   curY = row, curX = col;
  424: }
  425: 
  426: /* Clear out all terminal info.
  427:    Used before copying into it the info on the actual terminal.
  428:  */
  429: 
  430: void
  431: Wcm_clear ()
  432: {
  433:   bzero (&Wcm, sizeof Wcm);
  434:   UP = 0;
  435:   BC = 0;
  436: }
  437: 
  438: /*
  439:  * Initialized stuff
  440:  * Return 0 if can do CM.
  441:  * Return -1 if cannot.
  442:  * Return -2 if size not specified.
  443:  */
  444: 
  445: int
  446: Wcm_init ()
  447: {
  448: #if 0
  449:   if (Wcm.cm_abs && !Wcm.cm_ds)
  450:     return 0;
  451: #endif
  452:   if (Wcm.cm_abs)
  453:     return 0;
  454:   /* Require up and left, and, if no absolute, down and right */
  455:   if (!Wcm.cm_up || !Wcm.cm_left)
  456:     return - 1;
  457:   if (!Wcm.cm_abs && (!Wcm.cm_down || !Wcm.cm_right))
  458:     return - 1;
  459:   /* Check that we know the size of the screen.... */
  460:   if (Wcm.cm_rows <= 0 || Wcm.cm_cols <= 0)
  461:     return - 2;
  462:   return 0;
  463: }
  464: 
  465: /* arch-tag: bcf64c02-00f6-44ef-94b6-c56eab5b3dc4
  466:    (do not change this comment) */