/*
 * Copyright (C) 2004 Red Hat Inc.
 *
 * 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, 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 *
 * Authors:
 *     Mark McLoughlin <mark@skynet.ie>
 */

#include <glib.h>
#include <zlib.h>

#define FILE_PATH "/etc/services"
#define CHUNK_LEN 256

static z_stream inflate_stream;

static gboolean
do_decompression (const char *buf,
		  int         len)
{
  z_stream *zs = &inflate_stream;
  char outbuf [1024 * 5];

  zs->next_in  = (char *) buf;
  zs->avail_in = len;

  while (1)
    {
      int ret;

      zs->next_out  = outbuf;
      zs->avail_out = sizeof (outbuf);

      ret = inflate (zs, Z_SYNC_FLUSH);
      if (ret != Z_OK && ret != Z_STREAM_END)
	{
	  g_print ("inflate returned %d: %s\n",
		   ret, zs->msg ? zs->msg : "<no-error>");
	  return FALSE;
	}

      if (ret == Z_STREAM_END)
	{
	  g_print ("Reached end of stream\n");
	  inflateReset (zs);
	}

      if (zs->avail_in == 0)
	break;
    }

  return TRUE;
}

static gboolean
do_compression (z_stream   *zs,
		int         flush,
		const char *contents,
		int         len)
{
  char outbuf [32];

  g_print ("Compressing %d bytes with %s(%d) flush\n",
	   len, flush == Z_SYNC_FLUSH ? "sync" : "full", flush);

  zs->next_in  = (char *) contents;
  zs->avail_in = len;

  while (1)
    {
      int ret;

      zs->next_out  = outbuf;
      zs->avail_out = sizeof (outbuf);

      ret = deflate (zs, flush);
      if (ret != Z_OK && ret != Z_STREAM_END)
	{
	  g_print ("deflate returned %d: %s\n",
		   ret, zs->msg ? zs->msg : "<no-error>");
	  g_print ("\n---\n");
	  return FALSE;
	}

      g_assert (do_decompression (outbuf, sizeof (outbuf) - zs->avail_out));

      if (zs->avail_out != 0)
	{
	  g_print ("Finished compressing - %d bytes in final chunk\n",
		   sizeof (outbuf) - zs->avail_out);
	  break;
	}

      g_print ("Wrote out a 32 byte chunk\n");
    }

  g_assert (zs->avail_in == 0);

  g_print ("\n---\n");

  return TRUE;
}

int
main (int argc, char **argv)
{
  char *contents;
  gsize len;
  GError *error;
  z_stream zs;
  char *chunk;
  int chunk_len;

  inflate_stream.zalloc = Z_NULL;
  inflate_stream.zfree  = Z_NULL;
  inflate_stream.opaque = Z_NULL;

  if (inflateInit (&inflate_stream) != Z_OK)
    {
      g_warning ("Unable to initialize the decompression stream: %s\n",
		 inflate_stream.msg ? inflate_stream.msg : "<no-error>");
      return 1;
    }

  contents = NULL;
  len = 0;
  error = NULL;
  if (!g_file_get_contents (FILE_PATH, &contents, &len, &error))
    {
      g_warning ("Unable to read '%s': %s", FILE_PATH, error->message);
      g_error_free (error);
      return 1;
    }

  g_print ("Read %d bytes from %s\n", len, FILE_PATH);

  zs.zalloc = Z_NULL;
  zs.zfree  = Z_NULL;
  zs.opaque = Z_NULL;

  if (deflateInit (&zs,  Z_DEFAULT_COMPRESSION) != Z_OK)
    {
      g_warning ("Unable to initialize the compression stream: %s",
		 zs.msg ? zs.msg : "<no-error>");
      return 1;
    }

  chunk_len = CHUNK_LEN;
  chunk     = contents;

  /* Write all but the last chunk with this stream */
  while (len > chunk_len)
    {
      /* Use finish the stream with the last chunk */
      int flush = (len - chunk_len) > chunk_len ? Z_SYNC_FLUSH : Z_FINISH;

      g_assert (do_compression (&zs, flush, chunk, chunk_len));

      chunk += chunk_len;
      len   -= chunk_len;
    }

  deflateEnd (&zs);

  zs.zalloc = Z_NULL;
  zs.zfree  = Z_NULL;
  zs.opaque = Z_NULL;

  if (deflateInit (&zs,  Z_DEFAULT_COMPRESSION) != Z_OK)
    {
      g_warning ("Unable to initialize the compression stream: %s",
		 zs.msg ? zs.msg : "<no-error>");
      return 1;
    }

  g_assert (do_compression (&zs, Z_SYNC_FLUSH, chunk, len));

  deflateEnd (&zs);

  g_free (contents);

  inflateEnd (&inflate_stream);

  return 0;
}