/*
 * dri.c -- dri file handler
 * (C)Copyright 1998, 99 by Hiroshi Takekawa
 * This file is part of Enfle.
 *
 * Last Modified: Sun Jan  9 14:40:51 2000.
 * $Id: dri.c,v 1.12 2000/01/23 11:19:11 sian Exp $
 *
 * Enfle 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.
 *
 * Enfle 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
 */

#include "enfle.h"
#include "utils.h"
#include "plugin.h"
#include "dri.h"

/* define if you want to pack mapping table */
#define REMAP 1

int
#ifdef PIC
get_plugininfo(PluginInfo *p)
#else
archiver_dri_get_plugininfo(PluginInfo *p)
#endif
{
  p->version = 1;
  p->type = _Archiver;
  p->pluginname = "DRI Format Archiver Plugin version 0.2.1";
  p->pluginshortname = FORMAT_NAME;
  p->author = "Hiroshi Takekawa";
  p->dlhandle = NULL; /* set by plugin_load */
  p->functions.archiver.open = dri_archive_open;

  return 1;
}

int
dri_archive_open(Archive *ar)
{
  DRI_info *info;
  char buf[6];
  int ptrsize, mapsize;
  int i;

  if ((ar->fp = fopen(ar->filename, "rb")) == NULL)
    return 0;
#ifdef DEBUG
  fprintf(stderr, "dri_archive_open(): open %s\n", ar->filename);
#endif

  fseek(ar->fp, 0L, SEEK_END);
  ar->asize = ftell(ar->fp);
  fseek(ar->fp, 0L, SEEK_SET);

  if (fread(buf, 1, 6, ar->fp) != 6) {
    fclose(ar->fp);
    return 0;
  }

  ptrsize = (((buf[2] << 8) + buf[1]) << 8) + buf[0];
  mapsize = (((buf[5] << 8) + buf[4]) << 8) + buf[3] - ptrsize;

#ifdef DEBUG
  fprintf(stderr, "dri_archive_open: ptrsize = %d, mapsize = %d, asize = %d\n",
	  ptrsize, mapsize, ar->asize);
#endif

  if ((mapsize << 8) > ar->asize || (ptrsize << 8) > ar->asize || mapsize < 0 || ptrsize < 0) {
#ifdef DEBUG
    fprintf(stderr, "Invalid mapsize or ptrsize\n");
#endif
    fclose(ar->fp);
    return 0;
  }

  /* allocate DRI_info */
  if ((info = calloc(1, sizeof(DRI_info))) == NULL) {
    fprintf(stderr, "No enough memory for info\n");
    fclose(ar->fp);
    return 0;
  }

  fseek(ar->fp, 0L, SEEK_SET);
  if ((info->ptr = malloc(ptrsize << 8)) == NULL) {
#if DEBUG
    fprintf(stderr, "No enough memory for ptr\n");
#endif
    fclose(ar->fp);
    free(info);
    return 0;
  }
  if (fread(info->ptr, 1, ptrsize << 8, ar->fp) != ptrsize << 8) {
#ifdef DEBUG
    fprintf(stderr, "Error while reading ptr\n");
#endif
    fclose(ar->fp);
    free(info->ptr);
    free(info);
    return 0;
  }

  fseek(ar->fp, ptrsize << 8, SEEK_SET);
  if ((info->map = malloc(mapsize << 8)) == NULL) {
#ifdef DEBUG
    fprintf(stderr, "No enough memory for map\n");
#endif
    fclose(ar->fp);
    free(info->ptr);
    free(info);
    return 0;
  }
  if (fread(info->map, 1, mapsize << 8, ar->fp) != mapsize << 8) {
#ifdef DEBUG
    fprintf(stderr, "Error while reading map\n");
#endif
    fclose(ar->fp);
    free(info->map);
    free(info->ptr);
    free(info);
    return 0;
  }

  ar->nfiles = 0;
  for (i = 0; i < (mapsize << 8) / 3; i++)
    if (info->map[i * 3]) {
#ifdef REMAP
      info->map[ar->nfiles * 3] = info->map[i * 3];
      info->map[ar->nfiles * 3 + 1] = info->map[i * 3 + 1];
      info->map[ar->nfiles * 3 + 2] = info->map[i * 3 + 2];
#endif
      ar->nfiles++;
    }

#ifdef DEBUG
  fprintf(stderr, "nfiles = %d\n", ar->nfiles);
#endif

  /* sanity check */
  {
    int f_num = info->map[0];
    int f_loc = info->map[1] + (info->map[2] << 8);
    int f_ptr;

    if (f_loc * 3 + 2 > ptrsize << 8) {
#ifdef DEBUG
      fprintf(stderr, "Sanity check error: f_loc * 3 + 2 > ptrsize << 8\n");
#endif
      fclose(ar->fp);
      free(info->map);
      free(info->ptr);
      free(info);
      return 0;
    }
    f_ptr = (((info->ptr[f_loc * 3 + 2] << 8) +
	       info->ptr[f_loc * 3 + 1]) << 8) +
               info->ptr[f_loc * 3];
    if (f_num < 0 || f_num > 10 || f_loc < 0 || f_loc > 8192 || f_ptr < 0) {
#ifdef DEBUG
      fprintf(stderr, "Sanity check error: f_num = %d, f_loc = %d, f_ptr = %d\n",
              f_num, f_loc, f_ptr);
#endif
      fclose(ar->fp);
      free(info->map);
      free(info->ptr);
      free(info);
      return 0;
    }
  }

  ar->info = info;
  ar->format = FORMAT_NAME;
  ar->select = dri_archive_select;
  ar->seek = NULL;
  ar->tell = NULL;
  ar->read = NULL;
  ar->close = dri_archive_close;

  return 1;
}

int
dri_archive_select(Archive *ar, int index)
{
  DRI_info *info = ar->info;
  unsigned char buf[256 + 16];
  int f_num = 0, f_loc = 0, f_ptr = 0;
  long offset;

  if (index < 0)
    return 0;

  f_num = info->map[index * 3];
#ifdef DEBUG
  fprintf(stderr, "f_num = %d\n", f_num);
#endif
  if (f_num == 0)
    return 0;

  f_loc = (info->map[index * 3 + 2] << 8) + info->map[index * 3 + 1];
  f_ptr = (((info->ptr[f_loc * 3 + 2] << 8) +
	     info->ptr[f_loc * 3 + 1]) << 8) +
             info->ptr[f_loc * 3];
#ifdef DEBUG
  fprintf(stderr, "f_loc = %d, f_ptr = %d\n", f_loc, f_ptr);
#endif
  if (f_num < 0 || f_num > 10 || f_loc < 0 || f_loc > 8192 || f_ptr < 0)
    return 0;

  fseek(ar->fp, f_ptr << 8, SEEK_SET);
  if (fread(buf, 1, 256 + 16, ar->fp) != 256 + 16)
    return 0;

  offset = get_little_dword(buf);
  strncpy(ar->ifname, &buf[16], ((offset - 16) > 16) ? 16 : (offset - 16));
#ifdef DEBUG
  fprintf(stderr, "name = %s\n", ar->ifname);
#endif

  ar->size = get_little_dword(buf + 4);
  ar->offset =  (f_ptr << 8) + offset;
  fseek(ar->fp, ar->offset, SEEK_SET);

  return 1;
}

int
dri_archive_close(Archive *ar)
{
  int f = fclose(ar->fp);
  DRI_info *info = ar->info;

  free(info->map);
  free(info->ptr);
  free(ar->info);

  return f;
}