Subversion Repositories SvarDOS

/* Sved, the SvarDOS editor

 *

 * Copyright (C) 2023 Mateusz Viste

 *

 * Sved is released under the terms of the MIT license.

 *

 * Permission is hereby granted, free of charge, to any person obtaining a copy

 * of this software and associated documentation files (the "Software"), to

 * deal in the Software without restriction, including without limitation the

 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or

 * sell copies of the Software, and to permit persons to whom the Software is

 * furnished to do so, subject to the following conditions:

 *

 * The above copyright notice and this permission notice shall be included in

 * all copies or substantial portions of the Software.

 *

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE

 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING

 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS

 * IN THE SOFTWARE.

 */

#include <dos.h>

#include <fcntl.h>

#include <stdlib.h>

#include <string.h>

#include <malloc.h>   /* _fcalloc() */

#include "mdr\bios.h"

#include "mdr\cout.h"

#include "mdr\dos.h"

#include "mdr\keyb.h"

#include "svarlang\svarlang.h"

#define COL_TXT        0

#define COL_STATUSBAR1 1

#define COL_STATUSBAR2 2

#define COL_SCROLLBAR  3

#define COL_MSG        4

#define COL_ERR        5

/* preload the mono scheme (to be overloaded at runtime if color adapter present) */

static unsigned char scheme[] = {0x07, 0x70, 0x70, 0x70, 0x70, 0xf0};

#define SCROLL_CURSOR 0xB1

struct line {

  struct line far *prev;

  struct line far *next;

  unsigned short len;

  char payload[1];

};

struct file {

  int fd;

  struct line far *cursor;

  unsigned short xoffset;

  unsigned char cursorposx;

  unsigned char cursorposy;

  char lfonly; /* set if line endings are LF (CR/LF otherwise) */

  char fname[1]; /* dynamically sized */

};

/* adds a new line at cursor position into file linked list and dvance cursor

 * returns non-zero on error */

static int line_add(struct file *db, const char far *line) {

  unsigned short slen;

  struct line far *l;

  /* slen = strlen(line) (but for far pointer) */

  for (slen = 0; line[slen] != 0; slen++);

  /* trim out CR/LF line endings */

  if ((slen >= 2) && (line[slen - 2] == '\r')) {

    slen -= 2;

  } else if ((slen >= 1) && (line[slen - 1] == '\n')) {

    slen--;

  }

  l = _fcalloc(1, sizeof(struct line) + slen + 1);

  if (l == NULL) return(-1);

  l->prev = db->cursor;

  if (db->cursor) {

    l->next = db->cursor->next;

    db->cursor->next = l;

    l->next->prev = l;

  }

  db->cursor = l;

  _fmemcpy(l->payload, line, slen);

  l->len = slen;

  return(0);

}

/* append a nul-terminated string to line at cursor position */

static int line_append(struct file *f, const char far *buf, unsigned short len) {

  struct line far *n;

  if (sizeof(struct line) + f->cursor->len + len < len) return(-1); /* overflow check */

  n = _frealloc(f->cursor, sizeof(struct line) + f->cursor->len + len);

  if (n == NULL) return(-1);

  f->cursor = n;

  _fmemcpy(f->cursor->payload + f->cursor->len, buf, len);

  f->cursor->len += len;

  /* rewire the linked list */

  if (f->cursor->next) f->cursor->next->prev = f->cursor;

  if (f->cursor->prev) f->cursor->prev->next = f->cursor;

  return(0);

}

static void db_rewind(struct file *db) {

  if (db->cursor == NULL) return;

  while (db->cursor->prev) db->cursor = db->cursor->prev;

}

static void load_colorscheme(void) {

  scheme[COL_TXT] = 0x17;

  scheme[COL_STATUSBAR1] = 0x70;

  scheme[COL_STATUSBAR2] = 0x78;

  scheme[COL_SCROLLBAR] = 0x70;

  scheme[COL_MSG] = 0xf0;

  scheme[COL_ERR] = 0x4f;

}

static void ui_basic(unsigned char screenw, unsigned char screenh, const struct file *db) {

  unsigned char i;

  const char *s = svarlang_strid(0); /* HELP */

  unsigned char helpcol = screenw - (strlen(s) + 4);

  /* fill status bar with background */

  mdr_cout_char_rep(screenh - 1, 0, ' ', scheme[COL_STATUSBAR1], screenw);

  /* filename */

  if (db->fname[0] == 0) {

    mdr_cout_str(screenh - 1, 0, svarlang_str(0, 1), scheme[COL_STATUSBAR1], screenw);

  } else {

    mdr_cout_str(screenh - 1, 0, db->fname, scheme[COL_STATUSBAR1], screenw);

  }

  /* eol type */

  if (db->lfonly) {

    mdr_cout_str(screenh - 1, helpcol - 3, "LF", scheme[COL_STATUSBAR1], 5);

  } else {

    mdr_cout_str(screenh - 1, helpcol - 5, "CRLF", scheme[COL_STATUSBAR1], 5);

  }

  mdr_cout_str(screenh - 1, helpcol, " F1=", scheme[COL_STATUSBAR2], 40);

  mdr_cout_str(screenh - 1, helpcol + 4, s, scheme[COL_STATUSBAR2], 40);

  /* scroll bar */

  for (i = 0; i < (screenh - 1); i++) {

    mdr_cout_char(i, screenw - 1, SCROLL_CURSOR, scheme[COL_SCROLLBAR]);

  }

}

static void ui_msg(const char *msg, unsigned char screenw, unsigned char screenh, unsigned char *uidirtyfrom, unsigned char *uidirtyto, unsigned char attr) {

  unsigned short x, y, msglen, i;

  msglen = strlen(msg);

  y = (screenh - 4) >> 1;

  x = (screenw - msglen - 4) >> 1;

  for (i = y+2; i >= y; i--) mdr_cout_char_rep(i, x, ' ', attr, msglen + 2);

  mdr_cout_str(y+1, x+1, msg, attr, msglen);

  if (*uidirtyfrom > y) *uidirtyfrom = y;

  if (*uidirtyto < y+2) *uidirtyto = y+2;

}

static void ui_help(unsigned char screenw) {

#define MAXLINLEN 35

  unsigned short i, offset;

  offset = (screenw - MAXLINLEN + 2) >> 1;

  mdr_cout_cursor_hide();

  for (i = 2; i <= 15; i++) {

    mdr_cout_char_rep(i, offset - 2, ' ', scheme[COL_STATUSBAR1], MAXLINLEN + 2);

  }

  mdr_cout_str(3, offset, svarlang_str(0, 0), scheme[COL_STATUSBAR1], MAXLINLEN);

  for (i = 0; i <= 4; i++) {

    mdr_cout_str(5 + i, offset, svarlang_str(8, i), scheme[COL_STATUSBAR1], MAXLINLEN);

  }

  mdr_cout_str(5 + 1 + i, offset, svarlang_str(8, 10), scheme[COL_STATUSBAR1], MAXLINLEN);

  /* Press any key */

  mdr_cout_str(14, offset, svarlang_str(8, 11), scheme[COL_STATUSBAR1], MAXLINLEN);

  keyb_getkey();

  mdr_cout_cursor_show();

#undef MAXLINLEN

}

static void ui_refresh(const struct file *db, unsigned char screenw, unsigned char screenh, unsigned char uidirtyfrom, unsigned char uidirtyto) {

  unsigned char x;

  const struct line far *l;

  unsigned char y = db->cursorposy;

#ifdef DBG_REFRESH

  static char m = 'a';

  m++;

  if (m > 'z') m = 'a';

#endif

  /* rewind cursor line to first line that needs redrawing */

  for (l = db->cursor; y > uidirtyfrom; y--) l = l->prev;

  /* iterate over lines and redraw whatever needs to be redrawn */

  for (; l != NULL; l = l->next, y++) {

    /* skip lines that do not need to be refreshed */

    if (y < uidirtyfrom) continue;

    if (y > uidirtyto) break;

    x = 0;

    if (db->xoffset < l->len) {

      unsigned char i, limit;

      if (l->len - db->xoffset < screenw) {

        limit = l->len;

      } else {

        limit = db->xoffset + screenw - 1;

      }

      for (i = db->xoffset; i < limit; i++) mdr_cout_char(y, x++, l->payload[i], scheme[COL_TXT]);

    }

    /* write empty spaces until end of line */

    if (x < screenw - 1) mdr_cout_char_rep(y, x, ' ', scheme[COL_TXT], screenw - 1 - x);

#ifdef DBG_REFRESH

    mdr_cout_char(y, 0, m, scheme[COL_STATUSBAR1]);

#endif

    if (y == screenh - 2) break;

  }

  /* fill all lines below if empty (and they need to be redrawn) */

  if (l == NULL) {

    while ((y < screenh - 1) && (y < uidirtyto)) {

      mdr_cout_char_rep(y++, 0, ' ', scheme[COL_TXT], screenw - 1);

    }

  }

}

static void check_cursor_not_after_eol(struct file *db, unsigned char *uidirtyfrom, unsigned char *uidirtyto) {

  if (db->xoffset + db->cursorposx <= db->cursor->len) return;

  if (db->cursor->len < db->xoffset) {

    db->cursorposx = 0;

    db->xoffset = db->cursor->len;

    *uidirtyfrom = 0;

    *uidirtyto = 0xff;

  } else {

    db->cursorposx = db->cursor->len - db->xoffset;

  }

}

static void cursor_up(struct file *db, unsigned char *uidirtyfrom, unsigned char *uidirtyto) {

  if (db->cursor->prev != NULL) {

    db->cursor = db->cursor->prev;

    if (db->cursorposy == 0) {

      *uidirtyfrom = 0;

      *uidirtyto = 0xff;

    } else {

      db->cursorposy -= 1;

    }

  }

}

static void cursor_eol(struct file *db, unsigned char screenw, unsigned char *uidirtyfrom, unsigned char *uidirtyto) {

  /* adjust xoffset to make sure eol is visible on screen */

  if (db->xoffset > db->cursor->len) {

    db->xoffset = db->cursor->len - 1;

    *uidirtyfrom = 0;

    *uidirtyto = 0xff;

  }

  if (db->xoffset + screenw - 1 <= db->cursor->len) {

    db->xoffset = db->cursor->len - screenw + 2;

    *uidirtyfrom = 0;

    *uidirtyto = 0xff;

  }

  db->cursorposx = db->cursor->len - db->xoffset;

}

static void cursor_down(struct file *db, unsigned char screenh, unsigned char *uidirtyfrom, unsigned char *uidirtyto) {

  if (db->cursor->next != NULL) {

    db->cursor = db->cursor->next;

    if (db->cursorposy < screenh - 2) {

      db->cursorposy += 1;

    } else {

      *uidirtyfrom = 0;

      *uidirtyto = 0xff;

    }

  }

}

static void cursor_left(struct file *db, unsigned char screenw, unsigned char *uidirtyfrom, unsigned char *uidirtyto) {

  if (db->cursorposx > 0) {

    db->cursorposx -= 1;

  } else if (db->xoffset > 0) {

    db->xoffset -= 1;

    *uidirtyfrom = 0;

    *uidirtyto = 0xff;

  } else if (db->cursor->prev != NULL) { /* jump to end of line above */

    cursor_up(db, uidirtyfrom, uidirtyto);

    cursor_eol(db, screenw, uidirtyfrom, uidirtyto);

  }

}

static void cursor_home(struct file *db, unsigned char *uidirtyfrom, unsigned char *uidirtyto) {

  db->cursorposx = 0;

  if (db->xoffset != 0) {

    db->xoffset = 0;

    *uidirtyfrom = 0;

    *uidirtyto = 0xff;

  }

}

static void cursor_right(struct file *db, unsigned char screenw, unsigned char screenh, unsigned char *uidirtyfrom, unsigned char *uidirtyto) {

  if (db->cursor->len > db->xoffset + db->cursorposx) {

    if (db->cursorposx < screenw - 2) {

      db->cursorposx += 1;

    } else {

      db->xoffset += 1;

      *uidirtyfrom = 0;

      *uidirtyto = 0xff;

    }

  } else {

    cursor_down(db, screenh, uidirtyfrom, uidirtyto);

    cursor_home(db, uidirtyfrom, uidirtyto);

  }

}

static void del(struct file *db, unsigned char *uidirtyfrom, unsigned char *uidirtyto) {

  if (db->cursorposx + db->xoffset < db->cursor->len) {

    _fmemmove(db->cursor->payload + db->cursorposx + db->xoffset, db->cursor->payload + db->cursorposx + db->xoffset + 1, db->cursor->len - db->cursorposx - db->xoffset);

    db->cursor->len -= 1; /* do this AFTER memmove so the copy includes the nul terminator */

    *uidirtyfrom = db->cursorposy;

    *uidirtyto = db->cursorposy;

  } else if (db->cursor->next != NULL) { /* cursor is at end of line: merge current line with next one (if there is a next one) */

    struct line far *nextline = db->cursor->next;

    if (db->cursor->next->len > 0) {

      void far *newptr = _frealloc(db->cursor, sizeof(struct line) + db->cursor->len + db->cursor->next->len + 1);

      if (newptr != NULL) {

        db->cursor = newptr;

        _fmemcpy(db->cursor->payload + db->cursor->len, db->cursor->next->payload, db->cursor->next->len + 1);

        db->cursor->len += db->cursor->next->len;

      }

    }

    db->cursor->next = db->cursor->next->next;

    db->cursor->next->prev = db->cursor;

    if (db->cursor->prev != NULL) db->cursor->prev->next = db->cursor; /* in case realloc changed my pointer */

    _ffree(nextline);

    *uidirtyfrom = db->cursorposy;

    *uidirtyto = 0xff;

  }

}

static void bkspc(struct file *db, unsigned char screenw, unsigned char *uidirtyfrom, unsigned char *uidirtyto) {

  /* backspace is basically "left + del", not applicable only if cursor is on 1st byte of the file */

  if ((db->cursorposx == 0) && (db->xoffset == 0) && (db->cursor->prev == NULL)) return;

  cursor_left(db, screenw, uidirtyfrom, uidirtyto);

  del(db, uidirtyfrom, uidirtyto);

}

/* a custom argv-parsing routine that looks directly inside the PSP, avoids the need

 * of argc and argv, saves some 330 bytes of binary size */

static char *parseargv(void) {

  char *tail = (void *)0x81; /* THIS WORKS ONLY IN SMALL MEMORY MODEL */

  unsigned char count = 0;

  char *argv[4];

  while (count < 4) {

    /* jump to nearest arg */

    while (*tail == ' ') {

      *tail = 0;

      tail++;

    }

    if (*tail == '\r') {

      *tail = 0;

      break;

    }

    argv[count++] = tail;

    /* jump to next delimiter */

    while ((*tail != ' ') && (*tail != '\r')) tail++;

  }

  /* check args now */

  if (count == 0) return("");

  return(argv[0]);

}

static struct file *loadfile(const char *fname) {

  char buff[512]; /* read one entire sector at a time (faster) */

  char *buffptr;

  unsigned int len, llen;

  int fd;

  unsigned char eolfound;

  struct file *db;

  len = strlen(fname) + 1;

  db = calloc(1, sizeof(struct file) + len);

  if (db == NULL) return(NULL);

  memcpy(db->fname, fname, len);

  if (*fname == 0) goto SKIPLOADING;

  if (_dos_open(fname, O_RDONLY, &fd) != 0) {

    mdr_coutraw_puts("Failed to open file:");

    mdr_coutraw_puts(fname);

    free(db);

    return(NULL);

  }

  db->lfonly = 1;

  /* start by adding an empty line */

  if (line_add(db, "") != 0) {

    /* TODO ERROR HANDLING */

  }

  for (eolfound = 0;;) {

    unsigned short consumedbytes;

    if ((_dos_read(fd, buff, sizeof(buff), &len) != 0) || (len == 0)) break;

    buffptr = buff;

    FINDLINE:

    /* look for nearest \n */

    for (consumedbytes = 0;; consumedbytes++) {

      if (consumedbytes == len) {

        llen = consumedbytes;

        break;

      }

      if (buffptr[consumedbytes] == '\r') {

        llen = consumedbytes;

        consumedbytes++;

        db->lfonly = 0;

        break;

      }

      if (buffptr[consumedbytes] == '\n') {

        eolfound = 1;

        llen = consumedbytes;

        consumedbytes++;

        break;

      }

    }

    /* consumedbytes is the amount of bytes processed from buffptr,

     * llen is the length of line's payload (without its line terminator) */

    /* append content, if line is non-empty */

    if ((llen > 0) && (line_append(db, buffptr, llen) != 0)) {

      mdr_coutraw_puts("out of memory");

      free(db);

      db = NULL;

      break;

    }

    /* add a new line if necessary */

    if (eolfound) {

      if (line_add(db, "") != 0) {

      /* TODO ERROR HANDLING */

        mdr_coutraw_puts("out of memory");

        free(db);

        db = NULL;

        break;

      }

      eolfound = 0;

    }

    /* anything left? process the buffer leftover again */

    if (consumedbytes < len) {

      len -= consumedbytes;

      buffptr += consumedbytes;

      goto FINDLINE;

    }

  }

  _dos_close(fd);

  SKIPLOADING:

  /* add an empty line at end if not present already, also rewind cursor to top of file */

  if (db != NULL) {

    if ((db->cursor == NULL) || (db->cursor->len != 0)) line_add(db, "");

    db_rewind(db);

  }

  return(db);

}

static int savefile(const struct file *db) {

  int fd;

  const struct line far *l;

  unsigned bytes;

  unsigned char eollen;

  unsigned char eolbuf[2];

  if (_dos_open(db->fname, O_WRONLY, &fd) != 0) {

    return(-1);

  }

  l = db->cursor;

  while (l->prev) l = l->prev;

  /* preset line terminators */

  if (db->lfonly) {

    eolbuf[0] = '\n';

    eollen = 1;

  } else {

    eolbuf[0] = '\r';

    eolbuf[1] = '\n';

    eollen = 2;

  }

  while (l) {

    /* do not write the last empty line, it is only useful for edition */

    if (l->len != 0) {

      _dos_write(fd, l->payload, l->len, &bytes);

    } else if (l->next == NULL) {

      break;

    }

    _dos_write(fd, eolbuf, eollen, &bytes);

    l = l->next;

  }

  _dos_close(fd);

  return(0);

}

static void insert_in_line(struct file *db, const char *databuf, unsigned short len, unsigned char screenw, unsigned char screenh, unsigned char *uidirtyfrom, unsigned char *uidirtyto) {

  struct line far *n;

  n = _frealloc(db->cursor, sizeof(struct line) + db->cursor->len + len);

  if (n != NULL) {

    unsigned short off = db->xoffset + db->cursorposx;

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

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

    db->cursor = n;

    _fmemmove(db->cursor->payload + off + len, db->cursor->payload + off, db->cursor->len - off + 1);

    db->cursor->len += len;

    *uidirtyfrom = db->cursorposy;

    *uidirtyto = db->cursorposy;

    while (len--) {

      db->cursor->payload[off++] = *databuf;

      databuf++;

      cursor_right(db, screenw, screenh, uidirtyfrom, uidirtyto);

    }

  }

}

int main(void) {

  const char *fname;

  struct file *db;

  unsigned char screenw = 0, screenh = 0;

  unsigned char uidirtyfrom = 0, uidirtyto = 0xff; /* make sure to redraw entire UI at first run */

  {

    char nlspath[128], lang[8];

    svarlang_autoload_pathlist("sved", mdr_dos_getenv(nlspath, "NLSPATH", sizeof(nlspath)), mdr_dos_getenv(lang, "LANG", sizeof(lang)));

  }

  fname = parseargv();

  if (fname == NULL) {

    mdr_coutraw_puts(svarlang_str(1,0)); /* usage: sved file.txt */

    return(0);

  }

  /* load file */

  db = loadfile(fname);

  if (db == NULL) return(1);

  if (mdr_cout_init(&screenw, &screenh)) load_colorscheme();

  ui_basic(screenw, screenh, db);

  for (;;) {

    int k;

    check_cursor_not_after_eol(db, &uidirtyfrom, &uidirtyto);

    mdr_cout_locate(db->cursorposy, db->cursorposx);

    if (uidirtyfrom != 0xff) {

      ui_refresh(db, screenw, screenh, uidirtyfrom, uidirtyto);

      uidirtyfrom = 0xff;

    }

    k = keyb_getkey();

    if (k == 0x150) { /* down */

      cursor_down(db, screenh, &uidirtyfrom, &uidirtyto);

    } else if (k == 0x148) { /* up */

      cursor_up(db, &uidirtyfrom, &uidirtyto);

    } else if (k == 0x14D) { /* right */

      cursor_right(db, screenw, screenh, &uidirtyfrom, &uidirtyto);

    } else if (k == 0x14B) { /* left */

      cursor_left(db, screenw, &uidirtyfrom, &uidirtyto);

    } else if (k == 0x149) { /* pgup */

      // TODO

    } else if (k == 0x151) { /* pgdown */

      // TODO

    } else if (k == 0x147) { /* home */

       cursor_home(db, &uidirtyfrom, &uidirtyto);

    } else if (k == 0x14F) { /* end */

       cursor_eol(db, screenw, &uidirtyfrom, &uidirtyto);

    } else if (k == 0x1B) { /* ESC */

      break;

    } else if (k == 0x0D) { /* ENTER */

      /* add a new line */

      if (line_add(db, db->cursor->payload + db->xoffset + db->cursorposx) == 0) {

        /* trim the line above */

        db->cursor->prev->len = db->xoffset + db->cursorposx;

        db->cursor->prev->payload[db->cursor->prev->len] = 0;

        /* move cursor to the (new) line below */

        db->cursorposx = 0;

        if (db->cursorposy < screenh - 2) {

          uidirtyfrom = db->cursorposy;

          db->cursorposy++;

        } else {

          uidirtyfrom = 0;

        }

        uidirtyto = 0xff;

      } else {

        /* ERROR: OUT OF MEMORY */

      }

    } else if (k == 0x153) {  /* DEL */

      del(db, &uidirtyfrom, &uidirtyto);

    } else if (k == 0x008) { /* BKSPC */

      bkspc(db, screenw, &uidirtyfrom, &uidirtyto);

    } else if ((k >= 0x20) && (k <= 0xff)) { /* "normal" character */

      char c = k;

      insert_in_line(db, &c, 1, screenw, screenh, &uidirtyfrom, &uidirtyto);

    } else if (k == 0x009) { /* TAB */

      const char *tab = "        ";

      insert_in_line(db, tab, 8, screenw, screenh, &uidirtyfrom, &uidirtyto);

    } else if (k == 0x13b) { /* F1 */

      ui_help(screenw);

      uidirtyfrom = 0;

      uidirtyto = 0xff;

    } else if (k == 0x13f) { /* F5 */

      if (savefile(db) == 0) {

        ui_msg(svarlang_str(0, 2), screenw, screenh, &uidirtyfrom, &uidirtyto, scheme[COL_MSG]);

        mdr_bios_tickswait(11); /* 11 ticks is about 600 ms */

      } else {

        ui_msg(svarlang_str(0, 3), screenw, screenh, &uidirtyfrom, &uidirtyto, scheme[COL_ERR]);

        mdr_bios_tickswait(36); /* 2s */

      }

    } else if (k == 0x144) { /* F10 */

      db->lfonly ^= 1;

      ui_basic(screenw, screenh, db);

    } else if (k == 0x174) { /* CTRL+ArrRight - jump to next word */

      /* if currently cursor is on a non-space, then fast-forward to nearest space or EOL */

      for (;;) {

        if (db->xoffset + db->cursorposx == db->cursor->len) break;

        if (db->cursor->payload[db->xoffset + db->cursorposx] == ' ') break;

        cursor_right(db, screenw, screenh, &uidirtyfrom, &uidirtyto);

      }

      /* now skip to next non-space or end of file */

      for (;;) {

        cursor_right(db, screenw, screenh, &uidirtyfrom, &uidirtyto);

        if (db->cursor->payload[db->xoffset + db->cursorposx] != ' ') break;

        if ((db->cursor->next == NULL) && (db->cursorposx + db->xoffset == db->cursor->len)) break;

      }

    } else if (k == 0x173) { /* CTRL+ArrLeft - jump to prev word */

      cursor_left(db, screenw, &uidirtyfrom, &uidirtyto);

      /* if currently cursor is on a space, then fast-forward to nearest non-space or start of line */

      for (;;) {

        if ((db->xoffset == 0) && (db->cursorposx == 0)) break;

        if (db->cursor->payload[db->xoffset + db->cursorposx] != ' ') break;

        cursor_left(db, screenw, &uidirtyfrom, &uidirtyto);

      }

      /* now skip to next space or start of file */

      for (;;) {

        cursor_left(db, screenw, &uidirtyfrom, &uidirtyto);

        if (db->cursor->payload[db->xoffset + db->cursorposx] == ' ') {

          cursor_right(db, screenw, screenh, &uidirtyfrom, &uidirtyto);

          break;

        }

        if ((db->cursorposx == 0) && (db->xoffset == 0)) break;

      }

    } else { /* UNHANDLED KEY - TODO IGNORE THIS IN PRODUCTION RELEASE */

      char buff[4];

      const char *HEX = "0123456789ABCDEF";

      buff[0] = HEX[(k >> 8) & 15];

      buff[1] = HEX[(k >> 4) & 15];

      buff[2] = HEX[k & 15];

      mdr_cout_str(screenh - 1, 0, "UNHANDLED KEY: 0x", scheme[COL_STATUSBAR1], 17);

      mdr_cout_str(screenh - 1, 17, buff, scheme[COL_STATUSBAR1], 3);

      keyb_getkey();

      break;

    }

  }

  mdr_cout_close();

  /* no need to free memory, DOS will do it for me */

  return(0);

}