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Diffstat (limited to 'src/cm.c')
| -rw-r--r-- | src/cm.c | 414 |
1 files changed, 414 insertions, 0 deletions
diff --git a/src/cm.c b/src/cm.c new file mode 100644 index 00000000000..f88acff48f1 --- /dev/null +++ b/src/cm.c @@ -0,0 +1,414 @@ +/* Cursor motion subroutines for GNU Emacs. + Copyright (C) 1985 Free Software Foundation, Inc. + based primarily on public domain code written by Chris Torek + +This file is part of GNU Emacs. + +GNU Emacs is free software; you can redistribute it and/or modify +it under the terms of the GNU General Public License as published by +the Free Software Foundation; either version 1, or (at your option) +any later version. + +GNU Emacs is distributed in the hope that it will be useful, +but WITHOUT ANY WARRANTY; without even the implied warranty of +MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +GNU General Public License for more details. + +You should have received a copy of the GNU General Public License +along with GNU Emacs; see the file COPYING. If not, write to +the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */ + + +#include "config.h" +#include <stdio.h> +#include "cm.h" +#include "termhooks.h" + +#define BIG 9999 /* 9999 good on VAXen. For 16 bit machines + use about 2000.... */ + +char *tgoto (); + +extern char *BC, *UP; + +int cost; /* sums up costs */ + +/* ARGSUSED */ +evalcost (c) + char c; +{ + cost++; +} + +void +cmputc (c) + char c; +{ + if (termscript) + fputc (c & 0177, termscript); + putchar (c & 0177); +} + +/* NEXT TWO ARE DONE WITH MACROS */ +#if 0 +/* + * Assume the cursor is at row row, column col. Normally used only after + * clearing the screen, when the cursor is at (0, 0), but what the heck, + * let's let the guy put it anywhere. + */ + +static +at (row, col) { + curY = row; + curX = col; +} + +/* + * Add n columns to the current cursor position. + */ + +static +addcol (n) { + curX += n; + + /* + * If cursor hit edge of screen, what happened? + * N.B.: DO NOT!! write past edge of screen. If you do, you + * deserve what you get. Furthermore, on terminals with + * autowrap (but not magicwrap), don't write in the last column + * of the last line. + */ + + if (curX == Wcm.cm_cols) { + /* + * Well, if magicwrap, still there, past the edge of the + * screen (!). If autowrap, on the col 0 of the next line. + * Otherwise on last column. + */ + + if (Wcm.cm_magicwrap) + ; /* "limbo" */ + else if (Wcm.cm_autowrap) { + curX = 0; + curY++; /* Beware end of screen! */ + } + else + curX--; + } +} +#endif + +/* + * (Re)Initialize the cost factors, given the output speed of the terminal + * in the variable ospeed. (Note: this holds B300, B9600, etc -- ie stuff + * out of <sgtty.h>.) + */ + +cmcostinit () +{ + char *p; + +#define COST(x,e) (x ? (cost = 0, tputs (x, 1, e), cost) : BIG) +#define CMCOST(x,e) ((x == 0) ? BIG : (p = tgoto(x, 0, 0), COST(p ,e))) + + Wcm.cc_up = COST (Wcm.cm_up, evalcost); + Wcm.cc_down = COST (Wcm.cm_down, evalcost); + Wcm.cc_left = COST (Wcm.cm_left, evalcost); + Wcm.cc_right = COST (Wcm.cm_right, evalcost); + Wcm.cc_home = COST (Wcm.cm_home, evalcost); + Wcm.cc_cr = COST (Wcm.cm_cr, evalcost); + Wcm.cc_ll = COST (Wcm.cm_ll, evalcost); + Wcm.cc_tab = Wcm.cm_tabwidth ? COST (Wcm.cm_tab, evalcost) : BIG; + + /* + * These last three are actually minimum costs. When (if) they are + * candidates for the least-cost motion, the real cost is computed. + * (Note that "0" is the assumed to generate the minimum cost. + * While this is not necessarily true, I have yet to see a terminal + * for which is not; all the terminals that have variable-cost + * cursor motion seem to take straight numeric values. --ACT) + */ + + Wcm.cc_abs = CMCOST (Wcm.cm_abs, evalcost); + Wcm.cc_habs = CMCOST (Wcm.cm_habs, evalcost); + Wcm.cc_vabs = CMCOST (Wcm.cm_vabs, evalcost); + +#undef CMCOST +#undef COST +} + +/* + * Calculate the cost to move from (srcy, srcx) to (dsty, dstx) using + * up and down, and left and right, motions, and tabs. If doit is set + * actually perform the motion. + */ + +static +calccost (srcy, srcx, dsty, dstx, doit) +{ + register int deltay, + deltax, + c, + totalcost; + int ntabs, + n2tabs, + tabx, + tab2x, + tabcost; + register char *p; + + /* If have just wrapped on a terminal with xn, + don't believe the cursor position: give up here + and force use of absolute positioning. */ + + if (curX == Wcm.cm_cols) + goto fail; + + totalcost = 0; + if ((deltay = dsty - srcy) == 0) + goto x; + if (deltay < 0) + p = Wcm.cm_up, c = Wcm.cc_up, deltay = -deltay; + else + p = Wcm.cm_down, c = Wcm.cc_down; + if (c == BIG) { /* caint get thar from here */ + if (doit) + printf ("OOPS"); + return c; + } + totalcost = c * deltay; + if (doit) + while (--deltay >= 0) + tputs (p, 1, cmputc); +x: + if ((deltax = dstx - srcx) == 0) + goto done; + if (deltax < 0) { + p = Wcm.cm_left, c = Wcm.cc_left, deltax = -deltax; + goto dodelta; /* skip all the tab junk */ + } + /* Tabs (the toughie) */ + if (Wcm.cc_tab >= BIG || !Wcm.cm_usetabs) + goto olddelta; /* forget it! */ + + /* + * ntabs is # tabs towards but not past dstx; n2tabs is one more + * (ie past dstx), but this is only valid if that is not past the + * right edge of the screen. We can check that at the same time + * as we figure out where we would be if we use the tabs (which + * we will put into tabx (for ntabs) and tab2x (for n2tabs)). + */ + + ntabs = (deltax + srcx % Wcm.cm_tabwidth) / Wcm.cm_tabwidth; + n2tabs = ntabs + 1; + tabx = (srcx / Wcm.cm_tabwidth + ntabs) * Wcm.cm_tabwidth; + tab2x = tabx + Wcm.cm_tabwidth; + + if (tab2x >= Wcm.cm_cols) /* too far (past edge) */ + n2tabs = 0; + + /* + * Now set tabcost to the cost for using ntabs, and c to the cost + * for using n2tabs, then pick the minimum. + */ + + /* cost for ntabs + cost for right motion */ + tabcost = ntabs ? ntabs * Wcm.cc_tab + (dstx - tabx) * Wcm.cc_right + : BIG; + + /* cost for n2tabs + cost for left motion */ + c = n2tabs ? n2tabs * Wcm.cc_tab + (tab2x - dstx) * Wcm.cc_left + : BIG; + + if (c < tabcost) /* then cheaper to overshoot & back up */ + ntabs = n2tabs, tabcost = c, tabx = tab2x; + + if (tabcost >= BIG) /* caint use tabs */ + goto newdelta; + + /* + * See if tabcost is less than just moving right + */ + + if (tabcost < (deltax * Wcm.cc_right)) { + totalcost += tabcost; /* use the tabs */ + if (doit) + while (--ntabs >= 0) + tputs (Wcm.cm_tab, 1, cmputc); + srcx = tabx; + } + + /* + * Now might as well just recompute the delta. + */ + +newdelta: + if ((deltax = dstx - srcx) == 0) + goto done; +olddelta: + if (deltax > 0) + p = Wcm.cm_right, c = Wcm.cc_right; + else + p = Wcm.cm_left, c = Wcm.cc_left, deltax = -deltax; + +dodelta: + if (c == BIG) { /* caint get thar from here */ +fail: + if (doit) + printf ("OOPS"); + return BIG; + } + totalcost += c * deltax; + if (doit) + while (--deltax >= 0) + tputs (p, 1, cmputc); +done: + return totalcost; +} + +#if 0 +losecursor () +{ + curY = -1; +} +#endif + +#define USEREL 0 +#define USEHOME 1 +#define USELL 2 +#define USECR 3 + +cmgoto (row, col) +{ + int homecost, + crcost, + llcost, + relcost, + directcost; + int use; + char *p, + *dcm; + + /* First the degenerate case */ + if (row == curY && col == curX) /* already there */ + return; + + if (curY >= 0 && curX >= 0) + { + /* We may have quick ways to go to the upper-left, bottom-left, + * start-of-line, or start-of-next-line. Or it might be best to + * start where we are. Examine the options, and pick the cheapest. + */ + + relcost = calccost (curY, curX, row, col, 0); + use = USEREL; + if ((homecost = Wcm.cc_home) < BIG) + homecost += calccost (0, 0, row, col, 0); + if (homecost < relcost) + relcost = homecost, use = USEHOME; + if ((llcost = Wcm.cc_ll) < BIG) + llcost += calccost (Wcm.cm_rows - 1, 0, row, col, 0); + if (llcost < relcost) + relcost = llcost, use = USELL; + if ((crcost = Wcm.cc_cr) < BIG) { + if (Wcm.cm_autolf) + if (curY + 1 >= Wcm.cm_rows) + crcost = BIG; + else + crcost += calccost (curY + 1, 0, row, col, 0); + else + crcost += calccost (curY, 0, row, col, 0); + } + if (crcost < relcost) + relcost = crcost, use = USECR; + directcost = Wcm.cc_abs, dcm = Wcm.cm_abs; + if (row == curY && Wcm.cc_habs < BIG) + directcost = Wcm.cc_habs, dcm = Wcm.cm_habs; + else if (col == curX && Wcm.cc_vabs < BIG) + directcost = Wcm.cc_vabs, dcm = Wcm.cm_vabs; + } + else + { + directcost = 0, relcost = 100000; + dcm = Wcm.cm_abs; + } + + /* + * In the following comparison, the = in <= is because when the costs + * are the same, it looks nicer (I think) to move directly there. + */ + if (directcost <= relcost) + { + /* compute REAL direct cost */ + cost = 0; + p = dcm == Wcm.cm_habs ? tgoto (dcm, row, col) : + tgoto (dcm, col, row); + tputs (p, 1, evalcost); + if (cost <= relcost) + { /* really is cheaper */ + tputs (p, 1, cmputc); + curY = row, curX = col; + return; + } + } + + switch (use) + { + case USEHOME: + tputs (Wcm.cm_home, 1, cmputc); + curY = 0, curX = 0; + break; + + case USELL: + tputs (Wcm.cm_ll, 1, cmputc); + curY = Wcm.cm_rows - 1, curX = 0; + break; + + case USECR: + tputs (Wcm.cm_cr, 1, cmputc); + if (Wcm.cm_autolf) + curY++; + curX = 0; + break; + } + + (void) calccost (curY, curX, row, col, 1); + curY = row, curX = col; +} + +/* Clear out all terminal info. + Used before copying into it the info on the actual terminal. + */ + +Wcm_clear () +{ + bzero (&Wcm, sizeof Wcm); + UP = 0; + BC = 0; +} + +/* + * Initialized stuff + * Return 0 if can do CM. + * Return -1 if cannot. + * Return -2 if size not specified. + */ + +Wcm_init () +{ +#if 0 + if (Wcm.cm_abs && !Wcm.cm_ds) + return 0; +#endif + if (Wcm.cm_abs) + return 0; + /* Require up and left, and, if no absolute, down and right */ + if (!Wcm.cm_up || !Wcm.cm_left) + return - 1; + if (!Wcm.cm_abs && (!Wcm.cm_down || !Wcm.cm_right)) + return - 1; + /* Check that we know the size of the screen.... */ + if (Wcm.cm_rows <= 0 || Wcm.cm_cols <= 0) + return - 2; + return 0; +} |