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\cout.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

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

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

#define SCROLL_CURSOR 0xB1

struct line {

  struct line far *prev;

  struct line far *next;

  unsigned short len;

  char payload[1];

};

struct linedb {

  struct line far *topscreen;

  struct line far *cursor;

  unsigned short xoffset;

};

/* returns non-zero on error */

static int line_add(struct linedb *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);

}

static void db_rewind(struct linedb *db) {

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

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

  db->topscreen = db->cursor;

}

static void load_colorscheme(void) {

  scheme[COL_TXT] = 0x17;

  scheme[COL_STATUSBAR1] = 0x70;

  scheme[COL_STATUSBAR2] = 0x78;

  scheme[COL_SCROLLBAR] = 0x70;

}

static void ui_basic(unsigned char screenw, unsigned char screenh, const char *fname) {

  unsigned char i;

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

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

  /* clear screen */

  mdr_cout_cls(scheme[COL_TXT]);

  /* status bar */

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

    mdr_cout_char(screenh - 1, i, *fname, scheme[COL_STATUSBAR1]);

    if (*fname != 0) fname++;

  }

  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_refresh(const struct linedb *db, unsigned char screenw, unsigned char screenh, unsigned char uidirtyfrom, unsigned char uidirtyto) {

  unsigned char y = 0;

  unsigned char len;

  struct line far *l;

#ifdef DBG_REFRESH

  static char m = 'a';

  m++;

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

#endif

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

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

    if (y < uidirtyfrom) continue;

    if (y > uidirtyto) break;

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

      for (len = 0; l->payload[len] != 0; len++) mdr_cout_char(y, len, l->payload[len], scheme[COL_TXT]);

    } else {

      len = 0;

    }

    while (len < screenw - 1) mdr_cout_char(y, len++, ' ', scheme[COL_TXT]);

#ifdef DBG_REFRESH

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

#endif

    if (y == screenh - 2) break;

  }

}

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

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

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

    *cursorpos = 0;

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

    *uidirtyfrom = 0;

    *uidirtyto = 0xff;

  } else {

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

  }

}

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

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

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

    if (*cursorposy == 0) {

      db->topscreen = db->cursor;

      *uidirtyfrom = 0;

      *uidirtyto = 0xff;

    } else {

      *cursorposy -= 1;

    }

  }

}

static void cursor_eol(struct linedb *db, unsigned char *cursorposx, 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;

  }

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

}

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

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

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

    if (*cursorposy < screenh - 2) {

      *cursorposy += 1;

    } else {

      db->topscreen = db->topscreen->next;

      *uidirtyfrom = 0;

      *uidirtyto = 0xff;

    }

  }

}

static void cursor_left(struct linedb *db, unsigned char *cursorposx, unsigned char *cursorposy, unsigned char screenw, unsigned char *uidirtyfrom, unsigned char *uidirtyto) {

  if (*cursorposx > 0) {

    *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, cursorposy, uidirtyfrom, uidirtyto);

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

  }

}

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

  *cursorposx = 0;

  if (db->xoffset != 0) {

    db->xoffset = 0;

    *uidirtyfrom = 0;

    *uidirtyto = 0xff;

  }

}

static void del(struct linedb *db, unsigned char cursorposx, unsigned char cursorposy, unsigned char *uidirtyfrom, unsigned char *uidirtyto) {

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

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

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

    *uidirtyfrom = cursorposy;

    *uidirtyto = 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;

        /* update db->topscreen if needed */

        if (cursorposy == 0) db->topscreen = db->cursor;

      }

    }

    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 = cursorposy;

    *uidirtyto = 0xff;

  }

}

static void bkspc(struct linedb *db, unsigned char *cursorposx, unsigned char *cursorposy, 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 ((*cursorposx == 0) && (db->xoffset == 0) && (db->cursor->prev == NULL)) return;

  cursor_left(db, cursorposx, cursorposy, screenw, uidirtyfrom, uidirtyto);

  del(db, *cursorposx, *cursorposy, 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 != 1) return(NULL);

  return(argv[0]);

}

static int loadfile(struct linedb *db, const char *fname) {

  char buff[1024];

  unsigned int prevlen = 0, len, llen;

  int fd;

  int r = 0;

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

    mdr_coutraw_puts("Failed to open file:");

    mdr_coutraw_puts(fname);

    return(-1);

  }

  do {

    if (_dos_read(fd, buff + prevlen, sizeof(buff) - prevlen, &len) == 0) {

      len += prevlen;

    } else {

      len = prevlen;

    }

    /* look for nearest \n and replace with 0*/

    for (llen = 0; buff[llen] != '\n'; llen++) {

      if (llen == sizeof(buff)) break;

    }

    buff[llen] = 0;

    if ((llen > 0) && (buff[llen - 1])) buff[llen - 1] = 0; /* trim \r if line ending is cr/lf */

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

      mdr_coutraw_puts("out of memory");

      r = -1;

      break;

    }

    len -= llen + 1;

    memmove(buff, buff + llen + 1, len);

    prevlen = len;

  } while (len > 0);

  _dos_close(fd);

  return(r);

}

int main(void) {

  const char *fname;

  struct linedb db;

  unsigned char screenw = 0, screenh = 0;

  unsigned char cursorposx = 0, cursorposy = 0;

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

  bzero(&db, sizeof(db));

  svarlang_autoload_nlspath("sved");

  fname = parseargv();

  if (fname == NULL) {

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

    return(0);

  }

  /* load file */

  if (loadfile(&db, fname) != 0) return(1);

  /* add an empty line at end if not present already */

  if (db.cursor->len != 0) line_add(&db, "");

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

  ui_basic(screenw, screenh, fname);

  db_rewind(&db);

  for (;;) {

    int k;

    check_cursor_not_after_eol(&db, &cursorposx, &uidirtyfrom, &uidirtyto);

    mdr_cout_locate(cursorposy, cursorposx);

    if (uidirtyfrom != 0xff) {

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

      uidirtyfrom = 0xff;

    }

    k = keyb_getkey();

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

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

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

      cursor_up(&db, &cursorposy, &uidirtyfrom, &uidirtyto);

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

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

        if (cursorposx < screenw - 2) {

          cursorposx++;

        } else {

          db.xoffset++;

          uidirtyfrom = 0;

          uidirtyto = 0xff;

        }

      } else {

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

        cursor_home(&db, &cursorposx, &uidirtyfrom, &uidirtyto);

      }

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

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

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

      // TODO

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

      // TODO

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

       cursor_home(&db, &cursorposx, &uidirtyfrom, &uidirtyto);

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

       cursor_eol(&db, &cursorposx, 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 + cursorposx) == 0) {

        /* trim the line above */

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

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

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

        cursorposx = 0;

        if (cursorposy < screenh - 2) {

          uidirtyfrom = cursorposy;

          cursorposy++;

        } else {

          db.topscreen = db.topscreen->next;

          uidirtyfrom = 0;

        }

        uidirtyto = 0xff;

      } else {

        /* ERROR: OUT OF MEMORY */

      }

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

      del(&db, cursorposx, cursorposy, &uidirtyfrom, &uidirtyto);

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

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

    } 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();

  /* TODO free memory */

  return(0);

}