/*******************  start of original comments  ********************/
/*
 * Written by Douglas Thomson (1989/1990)
 *
 * This source code is released into the public domain.
 */

/*
 * Name:    dte - Doug's Text Editor program - window module
 * Purpose: This file contains the code associated with opening and sizing
 *           windows, and also displaying the help window.
 * File:    window.c
 * Author:  Douglas Thomson
 * System:  this file is intended to be system-independent
 * Date:    October 12, 1989
 */
/*********************  end of original comments   ********************/


/*
 * The window routines have been EXTENSIVELY rewritten.  Some routines were
 * changed so only one logical function is carried out, eg. 'initialize_window'.
 * I like the Microsoft way of resizing windows - just press the up and down
 * arrows to adjust the window to desired size.  I also like pressing one key
 * to change windows.  All of which are implemented.
 *
 * In tde, version 1.4, I added support for vertical windows.
 *
 * New editor name:  tde, the Thomson-Davis Editor.
 * Author:           Frank Davis
 * Date:             June 5, 1991, version 1.0
 * Date:             July 29, 1991, version 1.1
 * Date:             October 5, 1991, version 1.2
 * Date:             January 20, 1992, version 1.3
 * Date:             February 17, 1992, version 1.4
 * Date:             April 1, 1992, version 1.5
 * Date:             June 5, 1992, version 2.0
 *
 * This modification of Douglas Thomson's code is released into the
 * public domain, Frank Davis.  You may distribute it freely.
 */

#include "tdestr.h"
#include "common.h"
#include "define.h"
#include "tdefunc.h"


/*
 * Name:    initialize_window
 * Purpose: To open a new window
 * Date:    June 5, 1991
 * Returns: OK if window opened successfully
 *          ERROR if anything went wrong
 * Notes:   If this is first window then set up as normal displayed window
 *          otherwise make the present window invisible and open a new
 *          window in the same screen location as the old one.
 */
int  initialize_window( void )
{
int top;
int bottom;
int start_col;
int end_col;
WINDOW *wp;        /* used for scanning windows */
WINDOW *window;
register file_infos *fp;     /* used for scanning files */
register int rc;

   rc = OK;
   window = g_status.current_window;
   fp = g_status.current_file;
   if (window == NULL) {
      /*
       * special case if this is the first window on screen.
       */
      top = start_col = 0;
      bottom  = g_display.nlines;
      end_col = g_display.ncols - 1;
   } else {
      /*
       * else put the new window in same place as current window.
       * make current window invisible.  new window becomes current window.
       */
      top       = window->top_line - 1;
      bottom    = window->bottom_line;
      start_col = window->start_col;
      end_col   = window->end_col;
   }

   if (create_window( &wp, top, bottom, start_col, end_col, fp ) == ERROR) {
      /*
       * out of memory
       */
      error( WARNING, bottom, main4 );

      /*
       * This is a real nuisance. We had room for the file and the
       *  file structure, but not enough for the window as well.
       * Now we must free all the memory that has already been
       *  allocated.
       */
      if (fp->ref_count == 0) {
         if (fp->prev)
            fp->prev->next = fp->next;
         else
            g_status.file_list = fp->next;
         if (fp->next)
            fp->next->prev = fp->prev;
         g_status.end_mem = fp->start_text;
         free( fp );
         wp = g_status.current_window;
         if (wp != NULL && wp->visible)
            g_status.current_file = wp->file_info;
         else
            g_status.stop = TRUE;
      }
      rc = ERROR;
   }

   if (rc != ERROR) {
      /*
       * set up the new cursor position as appropriate
       */
      wp->cursor = cpf( fp->start_text );
      wp->ccol = wp->start_col;
      wp->rcol = wp->bcol = 0;
      wp->rline = 1l;
      wp->visible = TRUE;
      wp->letter = fp->next_letter++;
      if (window != NULL)
         window->visible = FALSE;

      /*
       * the new window becomes the current window.
       */
      g_status.current_window = wp;
   }
   return( rc );
}


/*
 * Name:    next_window
 * Purpose: To move to the next visible window.
 * Date:    June 5, 1991
 * Passed:  window:  pointer to current window
 * Notes:   Start with current window.  If next window exists then go to
 *          it else go to the first (top) window on screen.
 *          When I added vertical windows, finding the "correct" next
 *          window became extremely, unnecessarily, unmanageably complicated.
 *          let's just use a simple procedure to find the first available,
 *          visible, next window.
 */
int  next_window( WINDOW *window )
{
register WINDOW *wp;
int change;

   if (window != NULL) {
      change = FALSE;
      /*
       * start with current window and look for first next
       * visible window
       */
      wp = window->next;
      while (wp != NULL) {
         if (wp->visible) {
            change = TRUE;
            break;
         }
         wp = wp->next;
      }

      /*
       * if we haven't found a visible window yet, go to the beginning of
       * the list until we find a visible window.
       */
      if (!change) {
         wp = g_status.window_list;
         while (wp != window) {
            if (wp->visible) {
               change = TRUE;
               break;
            }
            wp = wp->next;
         }
      }
      if (change == TRUE) {
         un_copy_line( window->cursor, window, TRUE );
         g_status.current_window = wp;
         g_status.current_file = wp->file_info;
      }
   }
   return( OK );
}


/*
 * Name:    prev_window
 * Purpose: To move to the previous visible window.
 * Date:    June 5, 1991
 * Passed:  window:  pointer to current window
 * Notes:   Start with current window.  If previous window exists then go to
 *          it else go to the last (bottom) window on screen.  Opposite of
 *          next_window.
 *          when I added vertical windows, finding the "correct" previous
 *          window became extremely, unnecessarily, unmanageably complicated.
 *          let's just use a simple procedure to find the first available,
 *          visible, previous window.
 */
int  prev_window( WINDOW *window )
{
register WINDOW *wp;
int change;

   if (window != NULL) {
      change = FALSE;

      /*
       * start with current window and look for first previous
       * visible window
       */
      wp = window->prev;
      while (wp != NULL) {
         if (wp->visible) {
            change = TRUE;
            break;
         }
         wp = wp->prev;
      }

      /*
       * if we haven't found a visible window yet, go to the end of
       * the list and work backwards until we find a visible window.
       */
      if (!change) {
         wp = window->next;
         if (wp != NULL) {
            while (wp->next != NULL)
               wp = wp->next;
            while (wp != window) {
               if (wp->visible) {
                  change = TRUE;
                  break;
               }
               wp = wp->prev;
            }
         }
      }
      if (change == TRUE) {
         un_copy_line( window->cursor, window, TRUE );
         g_status.current_window = wp;
         g_status.current_file = wp->file_info;
      }
   }
   return( OK );
}


/*
 * Name:    split_horizontal
 * Purpose: To split screen horizontally at the cursor.
 * Date:    June 5, 1991
 * Passed:  window:  pointer to current window
 * Notes:   split the screen horizontally at the cursor position.
 */
int  split_horizontal( WINDOW *window )
{
register WINDOW *wp;
register WINDOW *win;  /* register pointer for window */
WINDOW *temp;
file_infos *file;       /* file structure for file belonging to new window */
int rc;

   win = window;
   /*
    * check that there is room for the window
    */
   if (win->bottom_line - win->cline < 2) {
      /*
       * move cursor up first
       */
      error( WARNING, win->bottom_line, win1 );
      rc = ERROR;
   } else {
      file = win->file_info;
      if (create_window( &temp, win->cline+1, win->bottom_line,
                         win->start_col, win->end_col, file ) == ERROR) {
         /*
          * out of memory
          */
         error( WARNING, win->bottom_line, main4 );
         rc = ERROR;
      } else {
         un_copy_line( win->cursor, win, TRUE );
         wp = temp;
         /*
          * record that the current window has lost some lines from
          *  the bottom for the new window, and adjust its page size
          *  etc accordingly.
          */
         win->bottom_line = win->cline;
         setup_window( win );
         display_current_window( win );

         /*
          * set up the new cursor position as appropriate
          */
         wp->rcol = win->rcol;
         wp->ccol = win->ccol;
         wp->bcol = win->bcol;
         wp->rline = win->rline;
         wp->cline = wp->cline + win->cline - (win->top_line + win->ruler);
         if (wp->cline > wp->bottom_line)
            wp->cline = wp->bottom_line;
         wp->cursor = win->cursor;
         wp->visible = TRUE;
         wp->vertical = win->vertical;
         wp->letter = file->next_letter++;
         wp->ruler  = mode.ruler;

         /*
          * the new window becomes the current window.
          */
         g_status.current_window = wp;

         show_window_count( g_status.window_count );
         show_window_header( wp );
         display_current_window( wp );
         if (wp->vertical)
            show_vertical_separator( wp );
         make_ruler( wp );
         show_ruler( wp );
         rc = OK;
      }
   }
   return( rc );
}


/*
 * Name:    split_vertical
 * Purpose: To split screen vertically at the cursor.
 * Date:    June 5, 1991
 * Passed:  window:  pointer to current window
 * Notes:   split the screen vertically at the cursor position.
 */
int  split_vertical( WINDOW *window )
{
register WINDOW *wp;
register WINDOW *win;  /* register pointer for window */
WINDOW *temp;
file_infos *file;       /* file structure for file belonging to new window */
int rc;

   win = window;
   /*
    * check that there is room for the window
    */
   if (win->start_col + 15 > win->ccol) {
      /*
       * move cursor right first
       */
      error( WARNING, win->bottom_line, win2 );
      rc = ERROR;
   } else if (win->end_col - 15 < win->ccol) {
      /*
       * move cursor left first
       */
      error( WARNING, win->bottom_line, win3 );
      rc = ERROR;
   } else {
      file = win->file_info;
      if (create_window( &temp, win->top_line-1, win->bottom_line,
                         win->ccol+1, win->end_col, file ) == ERROR) {
         /*
          * out of memory
          */
         error( WARNING, win->bottom_line, main4 );
         rc = ERROR;
      } else {
         un_copy_line( win->cursor, win, TRUE );
         wp = temp;
         /*
          * record that the current window has lost some columns from
          *  the window to the left for the new window
          */
         win->ccol = win->end_col = win->ccol - 1;
         win->rcol--;
         win->vertical = TRUE;
         show_window_header( win );
         show_vertical_separator( win );
         display_current_window( win );
         make_ruler( win );
         show_ruler( win );
         show_ruler_pointer( win );

         /*
          * set up the new cursor position as appropriate
          */
         wp->rcol = win->rcol;
         wp->ccol = wp->start_col + win->ccol - win->start_col;
         if (wp->ccol > wp->end_col)
            wp->ccol = wp->end_col;
         wp->bcol = win->bcol;
         wp->rline = win->rline;
         wp->cline = win->cline;
         wp->cursor = win->cursor;
         wp->visible = TRUE;
         wp->vertical = TRUE;
         wp->letter = file->next_letter++;
         wp->ruler  = mode.ruler;

         /*
          * the new window becomes the current window.
          */
         g_status.current_window = wp;

         check_virtual_col( wp, wp->rcol, wp->ccol );
         wp->file_info->dirty = FALSE;
         show_window_count( g_status.window_count );
         show_window_header( wp );
         display_current_window( wp );
         make_ruler( wp );
         show_ruler( wp );
         rc = OK;
      }
   }
   return( rc );
}


/*
 * Name:    show_vertical_separator
 * Purpose: To separate vertical screens
 * Date:    June 5, 1991
 * Passed:  window:  pointer to current window
 */
void show_vertical_separator( WINDOW *window )
{
int i;
int line;
int col;

   line = window->top_line - 1;
   col  = window->end_col + 1;
   if (col < g_display.ncols - 1) {
      i = window->bottom_line + 1 - line;
      while (i-- > 0)
         c_output( VERTICAL_CHAR, col, line++, g_display.head_color );
   }
}


/*
 * Name:    size_window
 * Purpose: To change the size of the current and one other window.
 * Date:    June 5, 1991
 * Passed:  window:  pointer to current window
 * Notes:   Use the Up and Down arrow keys to make the current window
 *          bigger or smaller.  The window above will either grow
 *          or contract accordingly.
 */
int  size_window( WINDOW *window )
{
char line_buff[(MAX_COLS+1)*2]; /* buffer for char and attribute  */
int func, c;
register WINDOW *above;
register WINDOW *win;
int resize;
int show_above_ruler;
int old_bottom_line;
int old_top_line;
int new_bottom_line;
int new_top_line;

   win = window;
   if (win->top_line != 1 && !win->vertical) {
      un_copy_line( win->cursor, win, TRUE );
      save_screen_line( 0, win->bottom_line, line_buff );
      /*
       * press up or down to change window size
       */
      set_prompt( win4, win->bottom_line );

      /*
       * resizing only affects current window and above visible window
       */
      above = g_status.window_list;
      while (above->bottom_line + 2 != win->top_line || !above->visible)
         above = above->next;
      if (above->vertical)
         /*
          * cannot resize vertical window
          */
         error( WARNING, win->bottom_line, win5 );
      else {
         old_top_line = win->top_line;
         old_bottom_line = above->bottom_line;
         show_above_ruler = FALSE;
         for (func=0; func != AbortCommand && func != Rturn; ) {

            /*
             * If user has redined the ESC and Return keys, make them Rturn and
             * AbortCommand in this function.
             */
            c = getkey( );
            func = getfunc( c );
            if (c == RTURN || func == NextLine || func == BegNextLine)
               func = Rturn;
            else if (c == ESC)
               func = AbortCommand;
            resize = FALSE;

            /*
             * if LineUp, make current window top line grow and bottom line
             * of above window shrink.   if window movement covers up current
             * line of window then we must adjust logical line and real line.
             */
            if (func == LineUp) {
               if (above->bottom_line > above->top_line + above->ruler) {
                  if (win->rline == (win->cline - (win->top_line+win->ruler-1)))
                     --win->cline;
                  --win->top_line;
                  if (above->cline == above->bottom_line)
                     --above->cline;
                  --above->bottom_line;
                  resize = TRUE;
                  if (mode.ruler) {
                     if (win->ruler == FALSE) {
                        if (win->cline == win->top_line)
                           ++win->cline;
                        if (win->cline > win->bottom_line)
                           win->cline = win->bottom_line;
                        win->ruler = TRUE;
                     }
                  }
               }

            /*
             * if LineDown, make current window top line shrink and bottom line
             * of above window grow.   if window movement covers up current
             * line of window then we must adjust logical line and real line.
             */
            } else if (func == LineDown) {
               if (win->bottom_line > win->top_line + win->ruler) {
                  if (win->cline == win->top_line + win->ruler)
                     ++win->cline;
                  ++win->top_line;
                  ++above->bottom_line;
                  resize = TRUE;
                  if (mode.ruler) {
                     if (above->ruler == FALSE) {
                        if (above->cline == above->top_line)
                           ++above->cline;
                        if (above->cline > above->bottom_line)
                           above->cline = above->bottom_line;
                        above->ruler = TRUE;
                        make_ruler( above );
                        show_above_ruler = TRUE;
                     }
                  }
               }
            }

            /*
             * if we resize a window then update window size and current and
             * real lines if needed.
             */
            if (resize == TRUE) {
               setup_window( above );
               display_current_window( above );
               if (show_above_ruler) {
                  show_ruler( above );
                  show_ruler_pointer( above );
                  show_above_ruler = FALSE;
               }
               setup_window( win );
               show_window_header( win );
               win->ruler = mode.ruler;
               make_ruler( win );
               show_ruler( win );
               show_ruler_pointer( win );
               display_current_window( win );
               save_screen_line( 0, win->bottom_line, line_buff );
               /*
                * press up or down to change window size
                */
               set_prompt( win4, win->bottom_line );
            }
         }
         new_top_line = win->top_line;
         new_bottom_line = above->bottom_line;
         for (above=g_status.window_list; above != NULL; above=above->next) {
            if (!above->visible) {
               if (above->bottom_line == old_bottom_line) {
                  above->bottom_line = new_bottom_line;
                  if (above->cline < new_bottom_line)
                     above->cline = new_bottom_line;
                  setup_window( above );
               } else if (above->top_line == old_top_line) {
                  above->top_line = new_top_line;
                  if (above->cline < new_top_line)
                     above->cline = new_top_line;
                  if ((long)(above->cline+1L - (above->top_line+above->ruler)) >
                                                                above->rline)
                     above->cline = (int)above->rline + above->top_line +
                                     above->ruler - 1;
                  setup_window( above );
               }
            }
         }
      }
      restore_screen_line( 0, win->bottom_line, line_buff );
   } else {
     if (win->vertical)
        /*
         * cannot resize vertical window
         */
        error( WARNING, win->bottom_line, win5 );
     else
        /*
         * cannot resize top window
         */
        error( WARNING, win->bottom_line, win6 );
   }
   return( OK );
}


/*
 * Name:    zoom_window
 * Purpose: To blow-up current window.
 * Date:    September 1, 1991
 * Passed:  window:  pointer to current window
 * Notes:   Make all windows, visible and hidden, full size.
 */
int  zoom_window( WINDOW *window )
{
register WINDOW *wp;

   if (window != NULL) {
      un_copy_line( window->cursor, window, TRUE );
      for (wp=g_status.window_list; wp != NULL; wp=wp->next) {
         if (wp != window && wp->visible)
            wp->visible = FALSE;
         if (wp->top_line != 1)
            wp->cline = wp->cline - (wp->top_line+wp->ruler) + 1;
         wp->top_line = 1;
         wp->bottom_line = g_display.nlines;
         wp->end_col   = g_display.ncols - 1;
         wp->start_col = 0;
         wp->vertical = FALSE;
         make_ruler( wp );
      }
      redraw_screen( window );
      show_ruler( window );
   }
   return( OK );
}


/*
 * Name:    next_hidden_window
 * Purpose: To display the window that is "behind" current window.
 * Date:    September 1, 1991
 * Passed:  window:  pointer to current window
 */
int  next_hidden_window( WINDOW *window )
{
int poof = FALSE;
register WINDOW *wp;

   if (window != NULL) {

      /*
       * look for next hidden window starting with current window.
       */
      wp = window;
      for (wp=window->next; wp != NULL && !poof; ) {
         if (!wp->visible)
            poof = TRUE;
         else
            wp = wp->next;
      }

      /*
       * if we haven't found an invisible window yet, start looking
       * for a hidden window from the beginning of the window list.
       */
      if (!poof) {
         for (wp=g_status.window_list; wp != NULL && !poof; ) {
            if (!wp->visible)
               poof = TRUE;
            else
               wp = wp->next;
         }
      }

      if (poof) {
         un_copy_line( window->cursor, window, TRUE );
         wp->cline = window->top_line + window->ruler +
                       (wp->cline - (wp->top_line + wp->ruler));
         wp->top_line = window->top_line;
         wp->bottom_line = window->bottom_line;
         wp->start_col = window->start_col;
         wp->end_col   = window->end_col;
         wp->vertical  = window->vertical;
         if (wp->cline < wp->top_line + wp->ruler)
            wp->cline = wp->top_line + wp->ruler;
         if (wp->cline > wp->bottom_line)
            wp->cline = wp->bottom_line;
         if ((wp->cline+1L - (wp->top_line+wp->ruler)) > wp->rline)
            wp->cline = (int)wp->rline + wp->top_line + wp->ruler - 1;
         wp->visible = TRUE;
         window->visible = FALSE;
         g_status.current_window = wp;
         redraw_current_window( wp );
         make_ruler( wp );
         show_ruler( wp );
      }
   }
   return( OK );
}


/*
 * Name:    setup_window
 * Purpose: To set the page length and the center line of a window, based
 *           on the top and bottom lines.
 * Date:    June 5, 1991
 * Passed:  window: window to be set up
 */
void setup_window( WINDOW *window )
{
   window->page = window->bottom_line - (window->top_line + window->ruler) -
                  g_status.overlap + 1;
   if (window->page < 1)
      window->page = 1;
}


/*
 * Name:    finish
 * Purpose: To remove the current window and terminate the program if no
 *           more windows are left.
 * Date:    June 5, 1991
 * Passed:  window:  pointer to current window
 * Notes:   Order of deciding which window becomes current window:
 *          1) If any invisible window with same top and bottom line,
 *          and start_col and end_col, then first invisible one becomes
 *          current window.
 *          2) window above if it exists becomes current window
 *          3) window below if it exists becomes current window
 *          4) window right if it exists becomes current window
 *          5) window left  if it exists becomes current window
 *          6) first available invisible window becomes current window.
 *          When I added vertical windows, this routine became a LOT
 *          more complicated.  To keep things reasonably sane, let's
 *          only close windows that have three common edges, eg.
 *
 *                    ÚÄÄÄÄÄÄÂÄÄÄÄÄÄÄÄÄÄ¿
 *                    ³      ³    no    ³
 *                    ³      ÃÄÄÄÄÄÂÄÄÄÄ´
 *                    ³      ³yes1 ³yes1³
 *                    ³  no  ÃÄÄÄÄÄÁÄÄÄÄ´
 *                    ³      ³   yes2   ³
 *                    ³      ÃÄÄÄÄÄÄÄÄÄÄ´
 *                    ³      ³   yes2   ³
 *                    ÀÄÄÄÄÄÄÁÄÄÄÄÄÄÄÄÄÄÙ
 *
 *          Windows with 'no' cannot be closed.  Windows with 'yes' can
 *          be combined with windows that have the same yes number.
 */
void finish( WINDOW *window )
{
register WINDOW *wp;   /* for scanning other windows */
register WINDOW *win;  /* register pointer for window */
file_infos *file, *fp;  /* for scanning other files */
long number;            /* number of bytes removed / copied */
int poof;
int cline;
int top, bottom;
int start_col, end_col;
int max_letter;
int file_change = FALSE;

   win = window;
   un_copy_line( win->cursor, win, TRUE );

   file = win->file_info;
   /*
    * remove all hidden windows that point to same file
    */
   file = win->file_info;
   for (wp=g_status.window_list; wp != NULL; wp=wp->next) {
      if (wp->file_info == file) {
         if (!wp->visible) {
            if (wp->prev == NULL) {
               if (wp->next == NULL)
                  g_status.stop = TRUE;
               else
                  g_status.window_list = wp->next;
            } else
               wp->prev->next = wp->next;
            if (wp->next)
               wp->next->prev = wp->prev;
            --wp->file_info->ref_count;
            free( wp );
            --g_status.window_count;
         }
      }
   }

   if (win->prev == NULL && win->next == NULL)
      g_status.stop = TRUE;
   poof = FALSE;

   if (g_status.stop != TRUE) {
      /*
       * see if there are any invisible windows with same top and bottom,
       * lines, and start_col and end_col as this window.  start looking at
       * end of window list.
       */
      top       = win->top_line;
      bottom    = win->bottom_line;
      start_col = win->start_col;
      end_col   = win->end_col;
      wp = g_status.window_list;
      if (wp != NULL) {
         while (wp->next != NULL)
            wp = wp->next;
      }
      while (wp != NULL && poof == FALSE) {
         if (wp->top_line == top         &&  wp->bottom_line == bottom  &&
             wp->start_col == start_col  &&  wp->end_col == end_col     &&
             !wp->visible)
            poof = TRUE;
         else
            wp = wp->prev;
      }

      if (poof == FALSE) {
         /*
          * see if there are any windows above
          */
         wp = g_status.window_list;
         while (wp != NULL && poof == FALSE) {
            if (wp->bottom_line+2 == win->top_line &&
                wp->start_col     == win->start_col &&
                wp->end_col       == win->end_col   && wp->visible) {
               poof = TRUE;
               top  = wp->top_line;
            } else
               wp = wp->next;
         }
         if (poof == FALSE) {
            /*
             * see if there are any windows below
             */
            wp = g_status.window_list;
            while (wp != NULL && poof == FALSE) {
               if (wp->top_line-2 == win->bottom_line  &&
                   wp->start_col     == win->start_col &&
                   wp->end_col       == win->end_col   && wp->visible) {
                  poof = TRUE;
                  bottom = wp->bottom_line;
               } else
                  wp = wp->next;
            }
         }
         if (poof == FALSE) {
            /*
             * see if there are any windows right
             */
            wp = g_status.window_list;
            while (wp != NULL && poof == FALSE) {
               if (wp->top_line    == win->top_line  &&
                   wp->bottom_line == win->bottom_line &&
                   wp->start_col-2 == win->end_col     && wp->visible) {
                  poof = TRUE;
                  end_col = wp->end_col;
               } else
                  wp = wp->next;
            }
         }
         if (poof == FALSE) {
            /*
             * see if there are any windows left
             */
            wp = g_status.window_list;
            while (wp != NULL && poof == FALSE) {
               if (wp->top_line    == win->top_line  &&
                   wp->bottom_line == win->bottom_line &&
                   wp->end_col+2   == win->start_col   && wp->visible) {
                  poof = TRUE;
                  start_col = wp->start_col;
               } else
                  wp = wp->next;
            }
         }
         if (poof == FALSE) {
            /*
             * see if there are any other invisible windows.  start looking
             * at the end of the window list.
             */
            wp = g_status.window_list;
            if (wp != NULL) {
               while (wp->next != NULL)
                  wp = wp->next;
            }
            while (wp != NULL && poof == FALSE) {
               if (!wp->visible)
                  poof = TRUE;
               else
                  wp = wp->prev;
            }
         }
      }
      if (poof) {
         wp->visible = TRUE;
         cline = wp->cline - (wp->top_line+wp->ruler);
         wp->top_line = top;
         wp->bottom_line = bottom;
         wp->cline = (wp->top_line+wp->ruler) + cline;
         if (wp->cline > wp->bottom_line)
            wp->cline = wp->top_line+wp->ruler;
         wp->start_col = start_col;
         wp->end_col   = end_col;
         if (start_col == 0 && end_col == g_display.ncols - 1)
            wp->vertical = FALSE;
         else
            wp->vertical = TRUE;
         check_virtual_col( wp, wp->rcol, wp->ccol );
         setup_window( wp );
         show_window_header( wp );
         if (wp->vertical)
            show_vertical_separator( wp );

         /*
          * The window above, below, or previously invisible becomes the new
          * current window.
          */
         g_status.current_window = wp;
      }
   }

   if (!poof && g_status.stop != TRUE)
      /*
       * cannot close current window
       */
      error( WARNING, win->bottom_line, win7 );
   else {

      /*
       * free unused file memory if necessary
       */
      if (--file->ref_count == 0) {

         /*
          * if a block is marked, unmark it
          */
         if (file == g_status.marked_file) {
            g_status.marked      = FALSE;
            g_status.marked_file = NULL;
         }

         for (fp=g_status.file_list; fp != NULL; fp=fp->next) {
            if (fp->file_no > file->file_no)
               fp->file_no--;
         }
         file_change = file->file_no;

         /*
          * no window now refers to this file, so remove file from the list
          */
         if (file->prev == NULL)
            g_status.file_list = file->next;
         else
            file->prev->next = file->next;
         if (file->next)
            file->next->prev = file->prev;

         /*
          * close up the gap in the memory buffer
          */
         number = ptoul( g_status.end_mem ) - ptoul( file->end_text );
         hw_move( file->start_text, file->end_text, number );
         number = ptoul( file->end_text ) - ptoul( file->start_text );
         g_status.end_mem = addltop( -number, g_status.end_mem );
         addorsub_all_cursors( win, -number );
         adjust_start_end( file, -number );

         /*
          * free the memory taken by the file structure
          */
         free( file );
         if (--g_status.file_count) {
            show_file_count( g_status.file_count );
            show_avail_mem( );
         }
      }

      /*
       * remove the current window from the window list
       */
      if (win->prev == NULL) {
         if (win->next != NULL)
            g_status.window_list = win->next;
      } else
         win->prev->next = win->next;

      if (win->next)
         win->next->prev = win->prev;

      /*
       * free the memory taken by the window structure
       */
      free( win );
      --g_status.window_count;

      if (g_status.stop == FALSE) {
         g_status.current_file = wp->file_info;
         wp->file_info->dirty = LOCAL;
         make_ruler( wp );
         show_ruler( wp );
         show_window_count( g_status.window_count );
         if (file_change) {
            for (wp=g_status.window_list; wp!=NULL; wp=wp->next)
               if (wp->visible)
                  show_window_number_letter( wp );
         } else {
            max_letter = 'a';
            for (wp=g_status.window_list; wp!=NULL; wp=wp->next) {
               if (wp->file_info == file && wp->letter > max_letter)
                  max_letter = wp->letter;
            }
            if (max_letter < file->next_letter - 1)
               file->next_letter = max_letter + 1;
         }
      }
   }
}


/*
 * Name:    create_window
 * Purpose: To allocate space for a new window structure and set up some
 *           of the relevant fields.
 * Date:    June 5, 1991
 * Passed:  window: pointer to window pointer
 *          top:    the top line of the new window
 *          bottom: the bottom line of the new window
 *          file:   the file structure to be associated with the new window
 * Returns: OK if window could be created
 *          ERROR if out of memory
 */
int  create_window( WINDOW **window, int top, int bottom, int start_col,
                    int end_col, file_infos *file )
{
WINDOW *wp;            /* temporary variable - use it instead of **window */
register WINDOW *prev;
int rc;                 /* return code */

   rc = OK;
   /*
    * allocate space for new window structure
    */
   if ((*window = (WINDOW *)calloc( 1, sizeof(WINDOW) )) == NULL) {
      /*
       * out of memory
       */
      error( WARNING, g_display.nlines, main4 );
      rc = ERROR;
   } else {

     /*
      * set up appropriate fields
      */
      wp              = *window;
      wp->file_info   = file;
      wp->top_line    = top+1;
      wp->bottom_line = bottom;
      wp->start_col   = start_col;
      wp->end_col     = end_col;
      wp->ruler       = mode.ruler;
      make_ruler( wp );
      wp->cline       = wp->top_line + wp->ruler;
      if (start_col == 0 && end_col == g_display.ncols-1)
         wp->vertical = FALSE;
      else
         wp->vertical = TRUE;
      wp->prev        = NULL;
      wp->next        = NULL;

      setup_window( wp );

      /*
       * add window into window list
       */
      prev = g_status.current_window;
      if (prev) {
         (*window)->prev = prev;
         if (prev->next)
            prev->next->prev = *window;
         (*window)->next = prev->next;
         prev->next = *window;
      }
      if (g_status.window_list == NULL)
         g_status.window_list = *window;


      /*
       * record that another window is referencing this file
       */
      ++file->ref_count;
      file->dirty = LOCAL;
      ++g_status.window_count;
   }
   return( rc );
}


/*
 * Name:    edit_file
 * Purpose: To allocate space for a new file structure and set up some
 *           of the relevant fields.
 * Date:    June 5, 1991
 * Passed:  name:  name of the file to edit
 * Returns: OK if file structure could be created
 *          ERROR if out of memory
 */
int  edit_file( char *name )
{
int rc;           /* return code */
int existing;
int line;
register file_infos *file; /* file structure for file belonging to new window */
file_infos *fp;
text_ptr next;      /* text pointer */
long size;

   rc = OK;
   line = g_display.nlines;
   if (hw_fattrib( name ) == OK) {
      existing = TRUE;
      /*
       * g_status.temp_end is set last character read in file
       */
      rc = load_file( name );
   } else {
      if (ceh.flag == ERROR)
         rc = ERROR;
      else {
         existing = FALSE;
         g_status.temp_end = cpf( g_status.end_mem );
      }
   }

   if (rc != ERROR) {
      /*
       * allocate a file structure for the new file
       */
      file = (file_infos *)calloc( 1, sizeof(file_infos) );
      if (file == NULL) {
         /*
          * out of memory
          */
         error( WARNING, g_display.nlines, main4 );
         rc = ERROR;
      } else {
         /*
          * add file into list
          */
         file->prev = NULL;
         file->next = NULL;
         if (g_status.file_list == NULL)
            g_status.file_list = file;
         else {
            fp = g_status.current_file;
            file->prev = fp;
            if (fp->next)
               fp->next->prev = file;
            file->next = fp->next;
            fp->next = file;
         }
      }
      if (rc != ERROR) {
         /*
          * set up all the info we need to know about a file, and
          *  record that we have used some more memory.
          */
         strcpy( file->file_name, name );
         get_fattr( name, &file->file_attrib );
         file->start_text = g_status.end_mem;
         *g_status.temp_end = CONTROL_Z;
         g_status.temp_end = cpf( g_status.temp_end );
         g_status.end_mem = g_status.temp_end + 1;
         g_status.temp_end = g_status.end_mem;
         file->end_text = g_status.end_mem;
         size = 0l;
         if (existing) {
            next = file->start_text = cpf( file->start_text );
            while ((next = find_next( next )) != NULL)
               size++;
         }
         file->length      = size;
         file->block_type  = NOTMARKED;
         file->block_end   = file->block_start = NULL;
         file->block_br    = file->block_er = 0l;
         file->block_bc    = file->block_ec = 0;
         file->ref_count   = 0;
         file->modified    = FALSE;
         file->backed_up   = FALSE;
         file->new_file    = !existing;
         file->next_letter = 'a';
         file->file_no     = ++g_status.file_count;
         g_status.current_file = file;
         make_backup_fname( file );
      }
   }
   return( rc );
}


/*
 * Name:    edit_another_file
 * Purpose: Bring in another file to editor.
 * Date:    June 5, 1991
 * Passed:  window:  pointer to current window
 * Notes:   New window replaces old window.  Old window becomes invisible.
 */
int  edit_another_file( WINDOW *window )
{
char fname[MAX_COLS];            /* new name for file */
register WINDOW *win;           /* put window pointer in a register */
int rc;

   win = window;
   un_copy_line( win->cursor, win, TRUE );
   /*
    * read in name, no default
    */
   fname[0] = '\0';
   /*
    * file name to edit
    */
   if ((rc = get_name( ed15, win->bottom_line, fname,
                 g_display.message_color )) == OK)
      rc = attempt_edit_display( fname, LOCAL );
   return( rc );
}


/*
 * Name:    edit_next_file
 * Purpose: edit next file on command line.
 * Date:    January 6, 1992
 * Passed:  window:  pointer to current window
 * Notes:   New window replaces old window.  Old window becomes invisible.
 */
int  edit_next_file( WINDOW *window )
{
char name[MAX_COLS];            /* new name for file */
int i;
int update_type;
register int rc = ERROR;
register WINDOW *win;           /* put window pointer in a register */

   win = window;
   update_type = win == NULL ? GLOBAL : LOCAL;
   if (g_status.arg < g_status.argc) {
      if (win != NULL)
         un_copy_line( win->cursor, win, TRUE );

      /*
       * while we haven't found a valid file, search thru the command
       * line path.
       * we may have an invalid file name when we finish matching all
       * files according to a pattern.  then, we need to go to the next
       * command line argument if it exists.
       */
      while (rc == ERROR && g_status.arg < g_status.argc) {

         /*
          * if we haven't starting searching for a file, check to see if
          * the file is a valid file name.  if no file is found, then let's
          * see if we can find according to a search pattern.
          */
         if (g_status.found_first == FALSE) {
            strcpy( name, g_status.argv[g_status.arg] );
            rc = get_fattr( name, &i );

            /*
             * a new or blank file generates a return code of 2.
             * a pattern with wild cards generates a return code of 3.
             */
            if (rc == OK || rc == 2) {
               ++g_status.arg;
               rc = OK;

            /*
             * if we get this far, we got an invalid path name.
             *  let's try to find a matching file name using pattern.
             */
            } else if (rc != ERROR) {
               rc = findfirst( &g_status.dta, name, NORMAL | READ_ONLY |
                               HIDDEN | SYSTEM | ARCHIVE );

               /*
                * if we found a file using wildcard characters,
                * set the g_status.found_first flag to true so we can
                * find the next matching file.  we need to save the
                * pathname stem so we know which directory we are working in.
                */
               if (rc == OK) {
                  g_status.found_first = TRUE;
                  i = strlen( name ) - 1;
                  while (i >= 0) {
                     if (name[i] == ':' || name[i] == '\\')
                        break;
                     --i;
                  }
                  name[++i] = '\0';
                  strcpy( g_status.path, name );
                  strcpy( name, g_status.path );
                  strcat( name, g_status.dta.name );
               } else {
                  ++g_status.arg;
                  if (win != NULL)
                     /*
                      * invalid path or file name
                      */
                     error( WARNING, win->bottom_line, win8 );
               }
            } else if (rc == ERROR)
               ++g_status.arg;
         } else {

            /*
             * we already found one file with wild card characters,
             * find the next matching file.
             */
            rc = findnext( &g_status.dta );
            if (rc == OK) {
               strcpy( name, g_status.path );
               strcat( name, g_status.dta.name );
            } else {
               g_status.found_first = FALSE;
               ++g_status.arg;
            }
         }

         /*
          * if everything is everything so far, set up the file
          * and window structures and bring the file into the editor.
          */
         if (rc == OK)
            rc = attempt_edit_display( name, update_type );

         /*
          * either there are no more matching files or we had an
          * invalid file name, set rc to ERROR and let's look at the
          * next file name or pattern on the command line.
          */
         else
            rc = ERROR;
      }
   }
   if (rc == ERROR  &&  g_status.arg >= g_status.argc  &&  win != NULL)
      /*
       * no more files to load
       */
      error( WARNING, win->bottom_line, win9 );
   return( rc );
}


/*
 * Name:    attempt_edit_display
 * Purpose: try to load then display a file
 * Date:    June 5, 1991
 * Passed:  fname:       file name to load
 *          update_type: update current window or entire screen
 * Notes:   When we first start the editor, we need to update the entire
 *          screen.  When we load in a new file, we only need to update
 *          the current window.
 */
int  attempt_edit_display( char *fname, int update_type )
{
register int rc;
WINDOW *win;

   rc = edit_file( fname );
   if (rc != ERROR) {
      rc = initialize_window( );
      if (rc != ERROR) {
         win = g_status.current_window;
         if (update_type == LOCAL) {
            redraw_current_window( win );
            show_file_count( g_status.file_count );
            show_window_count( g_status.window_count );
            show_avail_mem( );
         } else if (update_type == GLOBAL)
            redraw_screen( win );
         if (win->file_info->new_file) {
            g_status.command = AddLine;
            insert_newline( win );
            win->file_info->modified = FALSE;
         }
      }
   }
   return( rc );
}


/*
 * Name:    make_backup_fname
 * Purpose: add .bak to file name
 * Date:    January 6, 1992
 * Passed:  file: information allowing access to the current file
 */
void make_backup_fname( file_infos *file )
{
char name[MAX_COLS];            /* new name for file */
char *p;
int i;
int len;

   /*
    * if this is a new file then don't create a backup - can't backup
    *   a nonexisting file.
    */
   if (file->new_file)
      file->backed_up = TRUE;

   /*
    * find the file name extension if it exists
    */
   else {
      strcpy( name, file->file_name );
      len = strlen( name );
      for (i=len,p=name+len; i>=0; i--) {

         /*
          * we found the '.' extension character.  get out
          */
         if (*p == '.')
            break;

         /*
          * we found the drive or directory character.  no extension so
          *  set the pointer to the end of file name string.
          */
         else if (*p == '\\' || *p == ':') {
            p = name + len;
            break;

         /*
          * we're at the beginning of the string - no '.', drive, or directory
          *  char was found.  set the pointer to the end of file name string.
          */
         } else if (i == 0) {
            p = name + len;
            break;
         }
         --p;
      }
      strcpy( p, ".bak" );
      strcpy( file->backup_fname, name );
   }
}