/*
 * gz.c -- gz file handler
 * (C)Copyright 1999 by Hiroshi Takekawa
 * This file is part of Enfle.
 *
 * Last Modified: Wed Sep 29 20:32:44 1999.
 * $Id: gz.c,v 1.3 1999/09/29 12:22:54 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 "gz.h"

int
#ifdef PIC
get_plugininfo(PluginInfo *p)
#else
archiver_gz_get_plugininfo(PluginInfo *p)
#endif
{
  p->version = 1;
  p->type = _Archiver;
  p->pluginname = "GZ Format Archiver Plugin version 0.1";
  p->pluginshortname = FORMAT_NAME;
  p->author = "Hiroshi Takekawa";
  p->dlhandle = NULL; /* set by plugin_load */
  p->functions.archiver.open = gz_archive_open;

  return 1;
}

int
gz_archive_open(Archive *ar)
{
  unsigned char buf[2];
  GZ_info *info;

  if ((ar->fp = fopen(ar->filename, "rb")) == NULL)
    return 0;
#ifdef DEBUG
  fprintf(stderr, "gz_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, 2, ar->fp) != 2) {
    fclose(ar->fp);
    return 0;
  }
  fclose(ar->fp);

  /* check ID1 ID2 */
  if (buf[0] != 0x1f || buf[1] != 0x8b)
    return 0;

  if ((info = malloc(sizeof(GZ_info))) == NULL) {
    fprintf(stderr, "No enough memory for GZ_info\n");
    exit(1);
  }

  if ((info->gzfile = gzopen(ar->filename, "rb")) == NULL) {
    free(info);
    return 0;
  }

  ar->nfiles = 1;
  ar->info = info;
  ar->format = FORMAT_NAME;
  ar->select = NULL;
  ar->seek = gz_archive_seek;
  ar->tell = gz_archive_tell;
  ar->read = gz_archive_read;
  ar->close = gz_archive_close;

  return 1;
}

int
gz_archive_seek(Archive *ar, long ptr, int whence)
{
  GZ_info *info = ar->info;

  /* hmm... gzseek() does not support SEEK_END. */
  return (gzseek(info->gzfile, ptr, whence) == -1) ? -1 : 0;
}

int
gz_archive_tell(Archive *ar)
{
  GZ_info *info = ar->info;

  return gztell(info->gzfile);
}

int
gz_archive_read(Archive *ar, unsigned char *buf, int size)
{
  GZ_info *info = ar->info;
  int r, err;

  if ((r = gzread(info->gzfile, buf, size)) < 0) {
    fprintf(stderr, "%s\n", gzerror(info->gzfile, &err));
    return -1;
  }
  return r;
}

int
gz_archive_close(Archive *ar)
{
  GZ_info *info = ar->info;
  int f = gzclose(info->gzfile);

  free(ar->info);

  return f;
}