megazeux/helpsys.cpp

/* $Id$
 * MegaZeux
 *
 * Copyright (C) 1996 Greg Janson
 * Copyright (C) 1998 Matthew D. Williams - dbwilli@scsn.net
 *
 * This program 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 2 of
 * the License, or (at your option) any later version.
 *
 * This program 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 this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

// internal help system

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "scrdisp.h"
#include "helpsys.h"
#include "data.h"
#include "graphics.h"
#include "world.h"

int context = 72; // 72 = "No" context link
char *help = NULL;
int contexts[20];
int curr_context = 0;

void set_context(int con)
{
  contexts[curr_context++] = context;
  context = con;
}

void pop_context(void)
{
  context = contexts[--curr_context];
}

void help_system(World *mzx_world)
{
  FILE *fp;
  int t1, t2;
  cursor_mode_types old_cmode = get_cursor_mode();
  int where;
  int offs;
  int size;
  char file[13];
  char file2[13];
  char label[20];
  // Reserve memory (24k)
  help = (char *)malloc(24576);
  // Search context links
  fp = fopen(help_file, "rb");
  if(fp == NULL)
  {
    free(help);
    return;
  }
  t1 = fgetw(fp);
  fseek(fp, t1 * 21 + 4 + context * 12, SEEK_SET);
  // At proper context info
  where = fgetd(fp);    // Where file to load is
  size = fgetd(fp);     // Size of file to load
  offs = fgetd(fp);     //Offset within file of link

  // Jump to file
  fseek(fp, where, SEEK_SET);
  // Read it in
  fread(help, 1, size, fp);
  // Display it
  cursor_off();

  labelled:
  help_display(mzx_world, help, offs, file, label);
  // File?
  if(file[0])
  {
    //Yep. Search for file.
    fseek(fp, 2, SEEK_SET);
    for(t2 = 0; t2 < t1; t2++)
    {
      fread(file2, 1, 13, fp);
      if(!strcmp(file, file2)) break;
      fseek(fp, 8, SEEK_CUR);
    }
    if(t2 < t1)
    {
      //Found file.
      where = fgetd(fp);
      size = fgetd(fp);
      fseek(fp, where, SEEK_SET);
      fread(help, 1, size, fp);
      // Search for label
      for(t2 = 0; t2 < size; t2++)
      {
        if(help[t2] != 255) continue;
        if(help[t2 + 1] != ':') continue;
        if(!strcmp(help + t2 + 3, label)) break; // Found label!
      }
      if(t2 < size)
      {
        //Found label. t2 is offset.
        offs = t2;
        goto labelled;
      }
    }
  }
  //All done!
  fclose(fp);
  free(help);
  set_cursor_mode(old_cmode);
}