glib/gio/gzlibcompressor.c

/* GIO - GLib Input, Output and Streaming Library
 *
 * Copyright (C) 2009 Red Hat, Inc.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General
 * Public License along with this library; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place, Suite 330,
 * Boston, MA 02111-1307, USA.
 *
 * Author: Alexander Larsson <alexl@redhat.com>
 */

#include "config.h"

#include "gzlibcompressor.h"

#include <errno.h>
#include <zlib.h>
#include <string.h>

#include "gioerror.h"
#include "gioenums.h"
#include "gioenumtypes.h"
#include "glibintl.h"


enum {
  PROP_0,
  PROP_FORMAT,
  PROP_LEVEL
};

/**
 * SECTION:gzcompressor
 * @short_description: Zlib compressor
 * @include: gio/gio.h
 *
 * #GZlibCompressor is an implementation of #GConverter that
 * compresses data using zlib.
 */

static void g_zlib_compressor_iface_init          (GConverterIface *iface);

/**
 * GZlibCompressor:
 *
 * Zlib decompression
 */
struct _GZlibCompressor
{
  GObject parent_instance;

  GZlibCompressorFormat format;
  int level;
  z_stream zstream;
};

G_DEFINE_TYPE_WITH_CODE (GZlibCompressor, g_zlib_compressor, G_TYPE_OBJECT,
			 G_IMPLEMENT_INTERFACE (G_TYPE_CONVERTER,
						g_zlib_compressor_iface_init))

static void
g_zlib_compressor_finalize (GObject *object)
{
  GZlibCompressor *compressor;

  compressor = G_ZLIB_COMPRESSOR (object);

  deflateEnd (&compressor->zstream);

  G_OBJECT_CLASS (g_zlib_compressor_parent_class)->finalize (object);
}


static void
g_zlib_compressor_set_property (GObject      *object,
				  guint         prop_id,
				  const GValue *value,
				  GParamSpec   *pspec)
{
  GZlibCompressor *compressor;

  compressor = G_ZLIB_COMPRESSOR (object);

  switch (prop_id)
    {
    case PROP_FORMAT:
      compressor->format = g_value_get_enum (value);
      break;

    case PROP_LEVEL:
      compressor->level = g_value_get_int (value);
      break;

    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
      break;
    }

}

static void
g_zlib_compressor_get_property (GObject    *object,
				  guint       prop_id,
				  GValue     *value,
				  GParamSpec *pspec)
{
  GZlibCompressor *compressor;

  compressor = G_ZLIB_COMPRESSOR (object);

  switch (prop_id)
    {
    case PROP_FORMAT:
      g_value_set_enum (value, compressor->format);
      break;

    case PROP_LEVEL:
      g_value_set_int (value, compressor->level);
      break;

    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
      break;
    }
}

static void
g_zlib_compressor_init (GZlibCompressor *compressor)
{
}

static void
g_zlib_compressor_constructed (GObject *object)
{
  GZlibCompressor *compressor;
  int res;

  compressor = G_ZLIB_COMPRESSOR (object);

  if (compressor->format == G_ZLIB_COMPRESSOR_FORMAT_GZIP)
    {
      /* + 16 for gzip */
      res = deflateInit2 (&compressor->zstream,
			  compressor->level, Z_DEFLATED,
			  MAX_WBITS + 16, 8,
			  Z_DEFAULT_STRATEGY);
    }
  else if (compressor->format == G_ZLIB_COMPRESSOR_FORMAT_RAW)
    {
      /* negative wbits for raw */
      res = deflateInit2 (&compressor->zstream,
			  compressor->level, Z_DEFLATED,
			  -MAX_WBITS, 8,
			  Z_DEFAULT_STRATEGY);
    }
  else /* ZLIB */
    res = deflateInit (&compressor->zstream, compressor->level);

  if (res == Z_MEM_ERROR )
    g_error ("GZlibCompressor: Not enough memory for zlib use");

  if (res != Z_OK)
    g_warning ("unexpected zlib error: %s\n", compressor->zstream.msg);
}

static void
g_zlib_compressor_class_init (GZlibCompressorClass *klass)
{
  GObjectClass *gobject_class = G_OBJECT_CLASS (klass);

  gobject_class->finalize = g_zlib_compressor_finalize;
  gobject_class->constructed = g_zlib_compressor_constructed;
  gobject_class->get_property = g_zlib_compressor_get_property;
  gobject_class->set_property = g_zlib_compressor_set_property;

  g_object_class_install_property (gobject_class,
				   PROP_FORMAT,
				   g_param_spec_enum ("format",
						      P_("compression format"),
						      P_("The format of the compressed data"),
						      G_TYPE_ZLIB_COMPRESSOR_FORMAT,
						      G_ZLIB_COMPRESSOR_FORMAT_ZLIB,
						      G_PARAM_READWRITE | G_PARAM_CONSTRUCT_ONLY |
						      G_PARAM_STATIC_STRINGS));
  g_object_class_install_property (gobject_class,
				   PROP_LEVEL,
				   g_param_spec_int ("level",
						     P_("compression level"),
						     P_("The level of compression from 0 (no compression) to 9 (most compression), -1 for the default level"),
						     -1, 9,
						     -1,
						     G_PARAM_READWRITE |
						     G_PARAM_CONSTRUCT_ONLY |
						     G_PARAM_STATIC_STRINGS));
}

/**
 * g_zlib_compressor_new:
 * @format: The format to use for the compressed data
 * @level: compression level (0-9), -1 for default
 *
 * Creates a new #GZlibCompressor.
 *
 * Returns: a new #GZlibCompressor
 *
 * Since: 2.24
 **/
GZlibCompressor *
g_zlib_compressor_new (GZlibCompressorFormat format,
		       int level)
{
  GZlibCompressor *compressor;

  compressor = g_object_new (G_TYPE_ZLIB_COMPRESSOR,
			     "format", format,
			     "level", level,
			     NULL);

  return compressor;
}

static void
g_zlib_compressor_reset (GConverter *converter)
{
  GZlibCompressor *compressor = G_ZLIB_COMPRESSOR (converter);
  int res;

  res = deflateReset (&compressor->zstream);
  if (res != Z_OK)
    g_warning ("unexpected zlib error: %s\n", compressor->zstream.msg);
}

static GConverterResult
g_zlib_compressor_convert (GConverter *converter,
			   const void *inbuf,
			   gsize       inbuf_size,
			   void       *outbuf,
			   gsize       outbuf_size,
			   GConverterFlags flags,
			   gsize      *bytes_read,
			   gsize      *bytes_written,
			   GError    **error)
{
  GZlibCompressor *compressor;
  int res;
  int flush;

  compressor = G_ZLIB_COMPRESSOR (converter);

  compressor->zstream.next_in = (void *)inbuf;
  compressor->zstream.avail_in = inbuf_size;

  compressor->zstream.next_out = outbuf;
  compressor->zstream.avail_out = outbuf_size;

  flush = Z_NO_FLUSH;
  if (flags & G_CONVERTER_INPUT_AT_END)
    flush = Z_FINISH;
  else if (flags & G_CONVERTER_FLUSH)
    flush = Z_SYNC_FLUSH;

  res = deflate (&compressor->zstream, flush);

  if (res == Z_MEM_ERROR)
    {
      g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_FAILED,
			   _("Not enough memory"));
      return G_CONVERTER_ERROR;
    }

    if (res == Z_STREAM_ERROR)
    {
      g_set_error (error, G_IO_ERROR, G_IO_ERROR_FAILED,
		   _("Internal error: %s"), compressor->zstream.msg);
      return G_CONVERTER_ERROR;
    }

    if (res == Z_BUF_ERROR)
      {
	if (flags & G_CONVERTER_FLUSH)
	  return G_CONVERTER_FLUSHED;

	/* We do have output space, so this should only happen if we
	   have no input but need some */

	g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_PARTIAL_INPUT,
			     _("Need more input"));
	return G_CONVERTER_ERROR;
      }

  if (res == Z_OK || res == Z_STREAM_END)
    {
      *bytes_read = inbuf_size - compressor->zstream.avail_in;
      *bytes_written = outbuf_size - compressor->zstream.avail_out;

      if (res == Z_STREAM_END)
	return G_CONVERTER_FINISHED;
      return G_CONVERTER_CONVERTED;
    }

  g_assert_not_reached ();
}

static void
g_zlib_compressor_iface_init (GConverterIface *iface)
{
  iface->convert = g_zlib_compressor_convert;
  iface->reset = g_zlib_compressor_reset;
}