entered into RCS

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;
+}