gimp/app/xcf/xcf-load.c

/* The GIMP -- an image manipulation program
 * Copyright (C) 1995 Spencer Kimball and Peter Mattis
 *
 * 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

#include "config.h"

#include <stdio.h>
#include <string.h> /* strcmp, memcmp */

#include <glib-object.h>

#include "libgimpbase/gimpbase.h"
#include "libgimpcolor/gimpcolor.h"

#include "core/core-types.h"

#include "base/tile.h"
#include "base/tile-manager.h"
#include "base/tile-manager-private.h"

#include "config/gimpcoreconfig.h"

#include "core/gimp.h"
#include "core/gimpcontainer.h"
#include "core/gimpdrawable.h"
#include "core/gimpgrid.h"
#include "core/gimpimage.h"
#include "core/gimpimage-grid.h"
#include "core/gimpimage-guides.h"
#include "core/gimplayer.h"
#include "core/gimplayer-floating-sel.h"
#include "core/gimplayermask.h"
#include "core/gimpparasitelist.h"
#include "core/gimpselection.h"
#include "core/gimptemplate.h"
#include "core/gimpunit.h"

#include "text/gimptextlayer.h"
#include "text/gimptextlayer-xcf.h"

#include "vectors/gimpanchor.h"
#include "vectors/gimpstroke.h"
#include "vectors/gimpbezierstroke.h"
#include "vectors/gimpvectors.h"
#include "vectors/gimpvectors-compat.h"

#include "xcf-private.h"
#include "xcf-load.h"
#include "xcf-read.h"
#include "xcf-seek.h"

#include "gimp-intl.h"

/* #define GIMP_XCF_PATH_DEBUG */

static gboolean        xcf_load_image_props   (XcfInfo      *info,
                                               GimpImage    *image);
static gboolean        xcf_load_layer_props   (XcfInfo      *info,
                                               GimpImage    *image,
                                               GimpLayer    *layer,
                                               gboolean     *apply_mask,
                                               gboolean     *edit_mask,
                                               gboolean     *show_mask,
                                               guint32      *text_layer_flags);
static gboolean        xcf_load_channel_props (XcfInfo      *info,
                                               GimpImage    *image,
                                               GimpChannel **channel);
static gboolean        xcf_load_prop          (XcfInfo      *info,
                                               PropType     *prop_type,
                                               guint32      *prop_size);
static GimpLayer     * xcf_load_layer         (XcfInfo      *info,
                                               GimpImage    *image);
static GimpChannel   * xcf_load_channel       (XcfInfo      *info,
                                               GimpImage    *image);
static GimpLayerMask * xcf_load_layer_mask    (XcfInfo      *info,
                                               GimpImage    *image);
static gboolean        xcf_load_hierarchy     (XcfInfo      *info,
                                               TileManager  *tiles);
static gboolean        xcf_load_level         (XcfInfo      *info,
                                               TileManager  *tiles);
static gboolean        xcf_load_tile          (XcfInfo      *info,
                                               Tile         *tile);
static gboolean        xcf_load_tile_rle      (XcfInfo      *info,
                                               Tile         *tile,
                                               gint          data_length);
static GimpParasite  * xcf_load_parasite      (XcfInfo      *info);
static gboolean        xcf_load_old_paths     (XcfInfo      *info,
                                               GimpImage    *image);
static gboolean        xcf_load_old_path      (XcfInfo      *info,
                                               GimpImage    *image);
static gboolean        xcf_load_vectors       (XcfInfo      *info,
                                               GimpImage    *image);
static gboolean        xcf_load_vector        (XcfInfo      *info,
                                               GimpImage    *image);

#ifdef SWAP_FROM_FILE
static gboolean        xcf_swap_func          (gint          fd,
                                               Tile         *tile,
                                               gint          cmd,
                                               gpointer      user_data);
#endif


GimpImage *
xcf_load_image (Gimp    *gimp,
                XcfInfo *info)
{
  GimpImage    *image;
  GimpLayer    *layer;
  GimpChannel  *channel;
  GimpParasite *parasite;
  guint32       saved_pos;
  guint32       offset;
  gint          width;
  gint          height;
  gint          image_type;
  gint          num_successful_elements = 0;

  /* read in the image width, height and type */
  info->cp += xcf_read_int32 (info->fp, (guint32 *) &width, 1);
  info->cp += xcf_read_int32 (info->fp, (guint32 *) &height, 1);
  info->cp += xcf_read_int32 (info->fp, (guint32 *) &image_type, 1);

  image = gimp_create_image (gimp,
                              width, height,
                              image_type,
                              FALSE);

  gimp_image_undo_disable (image);

  /* read the image properties */
  if (! xcf_load_image_props (info, image))
    goto hard_error;

  /* check for a GimpGrid parasite */
  parasite = gimp_image_parasite_find (GIMP_IMAGE (image),
                                       gimp_grid_parasite_name ());
  if (parasite)
    {
      GimpGrid *grid = gimp_grid_from_parasite (parasite);

      if (grid)
        {
          gimp_parasite_list_remove (GIMP_IMAGE (image)->parasites,
                                     gimp_parasite_name (parasite));

          gimp_image_set_grid (GIMP_IMAGE (image), grid, FALSE);
        }
    }

  while (TRUE)
    {
      /* read in the offset of the next layer */
      info->cp += xcf_read_int32 (info->fp, &offset, 1);

      /* if the offset is 0 then we are at the end
       *  of the layer list.
       */
      if (offset == 0)
        break;

      /* save the current position as it is where the
       *  next layer offset is stored.
       */
      saved_pos = info->cp;

      /* seek to the layer offset */
      if (! xcf_seek_pos (info, offset, NULL))
        goto error;

      /* read in the layer */
      layer = xcf_load_layer (info, image);
      if (!layer)
        goto error;

      num_successful_elements++;

      /* add the layer to the image if its not the floating selection */
      if (layer != info->floating_sel)
        gimp_image_add_layer (image, layer,
                              gimp_container_num_children (image->layers));

      /* restore the saved position so we'll be ready to
       *  read the next offset.
       */
      if (! xcf_seek_pos (info, saved_pos, NULL))
        goto error;
    }

  while (TRUE)
    {
      /* read in the offset of the next channel */
      info->cp += xcf_read_int32 (info->fp, &offset, 1);

      /* if the offset is 0 then we are at the end
       *  of the channel list.
       */
      if (offset == 0)
        break;

      /* save the current position as it is where the
       *  next channel offset is stored.
       */
      saved_pos = info->cp;

      /* seek to the channel offset */
      if (! xcf_seek_pos (info, offset, NULL))
        goto error;

      /* read in the layer */
      channel = xcf_load_channel (info, image);
      if (!channel)
        goto error;

      num_successful_elements++;

      /* add the channel to the image if its not the selection */
      if (channel != image->selection_mask)
        gimp_image_add_channel (image, channel, -1);

      /* restore the saved position so we'll be ready to
       *  read the next offset.
       */
      if (! xcf_seek_pos (info, saved_pos, NULL))
        goto error;
    }

  if (info->floating_sel && info->floating_sel_drawable)
    floating_sel_attach (info->floating_sel, info->floating_sel_drawable);

  if (info->active_layer)
    gimp_image_set_active_layer (image, info->active_layer);

  if (info->active_channel)
    gimp_image_set_active_channel (image, info->active_channel);

  gimp_image_set_filename (image, info->filename);

  if (info->tattoo_state > 0)
    gimp_image_set_tattoo_state (image, info->tattoo_state);

  gimp_image_undo_enable (image);

  return image;

 error:
  if (num_successful_elements == 0)
    goto hard_error;

  g_message ("XCF: This file is corrupt!  I have loaded as much\n"
             "of it as I can, but it is incomplete.");

  gimp_image_undo_enable (image);

  return image;

 hard_error:
  g_message ("XCF: This file is corrupt!  I could not even\n"
             "salvage any partial image data from it.");

  g_object_unref (image);

  return NULL;
}

static gboolean
xcf_load_image_props (XcfInfo   *info,
                      GimpImage *image)
{
  PropType prop_type;
  guint32  prop_size;

  while (TRUE)
    {
      if (!xcf_load_prop (info, &prop_type, &prop_size))
        return FALSE;

      switch (prop_type)
        {
        case PROP_END:
          return TRUE;

        case PROP_COLORMAP:
          if (info->file_version == 0)
            {
              gint i;

              g_message (_("XCF warning: version 0 of XCF file format\n"
                           "did not save indexed colormaps correctly.\n"
                           "Substituting grayscale map."));
              info->cp +=
                xcf_read_int32 (info->fp, (guint32 *) &image->num_cols, 1);
              image->cmap = g_new (guchar, image->num_cols * 3);
              if (!xcf_seek_pos (info, info->cp + image->num_cols, NULL))
                return FALSE;

              for (i = 0; i<image->num_cols; i++)
                {
                  image->cmap[i*3+0] = i;
                  image->cmap[i*3+1] = i;
                  image->cmap[i*3+2] = i;
                }
            }
          else
            {
              info->cp +=
                xcf_read_int32 (info->fp, (guint32 *) &image->num_cols, 1);
              image->cmap = g_new (guchar, image->num_cols * 3);
              info->cp +=
                xcf_read_int8 (info->fp,
                               (guint8 *) image->cmap, image->num_cols * 3);
            }

          /* discard color map, if image is not indexed, this is just
	   * sanity checking to make sure gimp doesn't end up with an
	   * image state that is impossible.
           */
          if (gimp_image_base_type (image) != GIMP_INDEXED)
            {
              g_free (image->cmap);
              image->cmap = NULL;
              image->num_cols = 0;
            }
          break;

        case PROP_COMPRESSION:
          {
            guint8 compression;

            info->cp += xcf_read_int8 (info->fp, (guint8 *) &compression, 1);

            if ((compression != COMPRESS_NONE) &&
                (compression != COMPRESS_RLE) &&
                (compression != COMPRESS_ZLIB) &&
                (compression != COMPRESS_FRACTAL))
              {
                g_message ("unknown compression type: %d", (int) compression);
                return FALSE;
              }

            info->compression = compression;
          }
          break;

        case PROP_GUIDES:
          {
            gint32 position;
            gint8  orientation;
            gint   i, nguides;

            nguides = prop_size / (4 + 1);
            for (i = 0; i < nguides; i++)
              {
                info->cp += xcf_read_int32 (info->fp, (guint32 *) &position, 1);
                info->cp += xcf_read_int8 (info->fp, (guint8 *) &orientation, 1);

                /*  skip -1 guides from old XCFs  */
                if (position < 0)
                  continue;

                switch (orientation)
                  {
                  case XCF_ORIENTATION_HORIZONTAL:
                    gimp_image_add_hguide (image, position, FALSE);
                    break;

                  case XCF_ORIENTATION_VERTICAL:
                    gimp_image_add_vguide (image, position, FALSE);
                    break;

                  default:
                    g_message ("guide orientation out of range in XCF file");
                    continue;
                  }
              }

            /*  this is silly as the order of guides doesn't really matter,
             *  but it restores the list to it's original order, which
             *  cannot be wrong  --Mitch
             */
            image->guides = g_list_reverse (image->guides);
          }
          break;

        case PROP_RESOLUTION:
          {
            gfloat xres, yres;

            info->cp += xcf_read_float (info->fp, &xres, 1);
            info->cp += xcf_read_float (info->fp, &yres, 1);
            if (xres < GIMP_MIN_RESOLUTION || xres > GIMP_MAX_RESOLUTION ||
                yres < GIMP_MIN_RESOLUTION || yres > GIMP_MAX_RESOLUTION)
              {
                g_message ("Warning, resolution out of range in XCF file");
                xres = image->gimp->config->default_image->xresolution;
                yres = image->gimp->config->default_image->yresolution;
              }
            image->xresolution = xres;
            image->yresolution = yres;
          }
          break;

        case PROP_TATTOO:
          {
            info->cp += xcf_read_int32 (info->fp, &info->tattoo_state, 1);
          }
          break;

        case PROP_PARASITES:
          {
            glong         base = info->cp;
            GimpParasite *p;

            while (info->cp - base < prop_size)
              {
                p = xcf_load_parasite (info);
                gimp_image_parasite_attach (image, p);
                gimp_parasite_free (p);
              }
            if (info->cp - base != prop_size)
              g_message ("Error while loading an image's parasites");
          }
          break;

        case PROP_UNIT:
          {
            guint32 unit;

            info->cp += xcf_read_int32 (info->fp, &unit, 1);

            if ((unit <= GIMP_UNIT_PIXEL) ||
                (unit >= _gimp_unit_get_number_of_built_in_units (image->gimp)))
              {
                g_message ("Warning, unit out of range in XCF file, "
                           "falling back to inches");
                unit = GIMP_UNIT_INCH;
              }

            image->resolution_unit = unit;
          }
          break;

        case PROP_PATHS:
          xcf_load_old_paths (info, image);
          break;

        case PROP_USER_UNIT:
          {
            gchar    *unit_strings[5];
            float     factor;
            guint32   digits;
            GimpUnit  unit;
            gint      num_units;
            gint      i;

            info->cp += xcf_read_float (info->fp, &factor, 1);
            info->cp += xcf_read_int32 (info->fp, &digits, 1);
            info->cp += xcf_read_string (info->fp, unit_strings, 5);

            for (i = 0; i < 5; i++)
              if (unit_strings[i] == NULL)
                unit_strings[i] = g_strdup ("");

            num_units = _gimp_unit_get_number_of_units (image->gimp);

            for (unit = _gimp_unit_get_number_of_built_in_units (image->gimp);
                 unit < num_units; unit++)
              {
                /* if the factor and the identifier match some unit
                 * in unitrc, use the unitrc unit
                 */
                if ((ABS (_gimp_unit_get_factor (image->gimp,
                                                 unit) - factor) < 1e-5) &&
                    (strcmp (unit_strings[0],
                             _gimp_unit_get_identifier (image->gimp,
                                                        unit)) == 0))
                  {
                    break;
                  }
              }

            /* no match */
            if (unit == num_units)
              unit = _gimp_unit_new (image->gimp,
                                     unit_strings[0],
                                     factor,
                                     digits,
                                     unit_strings[1],
                                     unit_strings[2],
                                     unit_strings[3],
                                     unit_strings[4]);

            image->resolution_unit = unit;

            for (i = 0; i < 5; i++)
              g_free (unit_strings[i]);
          }
         break;

        case PROP_VECTORS:
          {
            guint32 base = info->cp;

            if (xcf_load_vectors (info, image))
              {
                if (base + prop_size != info->cp)
                  {
                    g_warning ("Mismatch in PROP_VECTORS size: skipping %d bytes.",
                               base + prop_size - info->cp);
                    xcf_seek_pos (info, base + prop_size, NULL);
                  }
              }
            else
              {
                /* skip silently since we don't understand the format and
                 * xcf_load_vectors already explained what was wrong
                 */
                xcf_seek_pos (info, base + prop_size, NULL);
              }
          }
          break;

        default:
#ifdef GIMP_UNSTABLE
          g_printerr ("unexpected/unknown image property: %d (skipping)",
                      prop_type);
#endif
          {
            guint8 buf[16];
            guint  amount;

            while (prop_size > 0)
              {
                amount = MIN (16, prop_size);
                info->cp += xcf_read_int8 (info->fp, buf, amount);
                prop_size -= MIN (16, amount);
              }
          }
          break;
        }
    }

  return FALSE;
}

static gboolean
xcf_load_layer_props (XcfInfo   *info,
                      GimpImage *image,
                      GimpLayer *layer,
                      gboolean  *apply_mask,
                      gboolean  *edit_mask,
                      gboolean  *show_mask,
                      guint32   *text_layer_flags)
{
  PropType prop_type;
  guint32  prop_size;

  while (TRUE)
    {
      if (!xcf_load_prop (info, &prop_type, &prop_size))
        return FALSE;

      switch (prop_type)
        {
        case PROP_END:
          return TRUE;

        case PROP_ACTIVE_LAYER:
          info->active_layer = layer;
          break;

        case PROP_FLOATING_SELECTION:
          info->floating_sel = layer;
          info->cp +=
            xcf_read_int32 (info->fp,
                            (guint32 *) &info->floating_sel_offset, 1);
          break;

        case PROP_OPACITY:
          {
            guint32 opacity;

            info->cp += xcf_read_int32 (info->fp, &opacity, 1);
            layer->opacity = CLAMP ((gdouble) opacity / 255.0,
                                    GIMP_OPACITY_TRANSPARENT,
                                    GIMP_OPACITY_OPAQUE);
          }
          break;

        case PROP_VISIBLE:
          {
            gboolean visible;

            info->cp += xcf_read_int32 (info->fp, (guint32 *) &visible, 1);
            gimp_item_set_visible (GIMP_ITEM (layer),
                                   visible ? TRUE : FALSE, FALSE);
          }
          break;

        case PROP_LINKED:
          {
            gboolean linked;

            info->cp += xcf_read_int32 (info->fp, (guint32 *) &linked, 1);
            gimp_item_set_linked (GIMP_ITEM (layer),
                                  linked ? TRUE : FALSE, FALSE);
          }
          break;

        case PROP_LOCK_ALPHA:
          info->cp +=
            xcf_read_int32 (info->fp, (guint32 *) &layer->lock_alpha, 1);
          break;

        case PROP_APPLY_MASK:
          info->cp += xcf_read_int32 (info->fp, (guint32 *) apply_mask, 1);
          break;

        case PROP_EDIT_MASK:
          info->cp += xcf_read_int32 (info->fp, (guint32 *) edit_mask, 1);
          break;

        case PROP_SHOW_MASK:
          info->cp += xcf_read_int32 (info->fp, (guint32 *) show_mask, 1);
          break;

        case PROP_OFFSETS:
          info->cp +=
            xcf_read_int32 (info->fp,
                            (guint32 *) &GIMP_ITEM (layer)->offset_x, 1);
          info->cp +=
            xcf_read_int32 (info->fp,
                            (guint32 *) &GIMP_ITEM (layer)->offset_y, 1);
          break;

        case PROP_MODE:
          info->cp += xcf_read_int32 (info->fp, (guint32 *) &layer->mode, 1);
          break;

        case PROP_TATTOO:
          info->cp += xcf_read_int32 (info->fp,
                                      (guint32 *) &GIMP_ITEM (layer)->tattoo,
                                      1);
          break;

        case PROP_PARASITES:
          {
            glong         base = info->cp;
            GimpParasite *p;

            while (info->cp - base < prop_size)
              {
                p = xcf_load_parasite (info);
                gimp_item_parasite_attach (GIMP_ITEM (layer), p);
                gimp_parasite_free (p);
              }
            if (info->cp - base != prop_size)
              g_message ("Error while loading a layer's parasites");
          }
          break;

        case PROP_TEXT_LAYER_FLAGS:
          info->cp += xcf_read_int32 (info->fp, text_layer_flags, 1);
          break;

        default:
          {
            guint8 buf[16];
            guint  amount;

#ifdef GIMP_UNSTABLE
            g_printerr ("unexpected/unknown layer property: %d (skipping)",
                        prop_type);
#endif
            while (prop_size > 0)
              {
                amount = MIN (16, prop_size);
                info->cp += xcf_read_int8 (info->fp, buf, amount);
                prop_size -= MIN (16, amount);
              }
          }
          break;
        }
    }

  return FALSE;
}

static gboolean
xcf_load_channel_props (XcfInfo      *info,
                        GimpImage    *image,
                        GimpChannel **channel)
{
  PropType prop_type;
  guint32  prop_size;

  while (TRUE)
    {
      if (!xcf_load_prop (info, &prop_type, &prop_size))
        return FALSE;

      switch (prop_type)
        {
        case PROP_END:
          return TRUE;

        case PROP_ACTIVE_CHANNEL:
          info->active_channel = *channel;
          break;

        case PROP_SELECTION:
          g_object_unref (image->selection_mask);
          image->selection_mask =
            gimp_selection_new (image,
                                gimp_item_width (GIMP_ITEM (*channel)),
                                gimp_item_height (GIMP_ITEM (*channel)));
          g_object_ref (image->selection_mask);
          gimp_item_sink (GIMP_ITEM (image->selection_mask));

          tile_manager_unref (GIMP_DRAWABLE (image->selection_mask)->tiles);
          GIMP_DRAWABLE (image->selection_mask)->tiles =
            GIMP_DRAWABLE (*channel)->tiles;
          GIMP_DRAWABLE (*channel)->tiles = NULL;
          g_object_unref (*channel);
          *channel = image->selection_mask;
          (*channel)->boundary_known = FALSE;
          (*channel)->bounds_known   = FALSE;
          break;

        case PROP_OPACITY:
          {
            guint32 opacity;

            info->cp += xcf_read_int32 (info->fp, &opacity, 1);
            (*channel)->color.a = opacity / 255.0;
          }
          break;

        case PROP_VISIBLE:
          {
            gboolean visible;

            info->cp += xcf_read_int32 (info->fp, (guint32 *) &visible, 1);
            gimp_item_set_visible (GIMP_ITEM (*channel),
                                   visible ? TRUE : FALSE, FALSE);
          }
          break;

        case PROP_LINKED:
          {
            gboolean linked;

            info->cp += xcf_read_int32 (info->fp, (guint32 *) &linked, 1);
            gimp_item_set_linked (GIMP_ITEM (*channel),
                                  linked ? TRUE : FALSE, FALSE);
          }
          break;

        case PROP_SHOW_MASKED:
          {
            gboolean show_masked;

            info->cp += xcf_read_int32 (info->fp, (guint32 *) &show_masked, 1);
            gimp_channel_set_show_masked (*channel, show_masked);
          }
          break;

        case PROP_COLOR:
          {
            guchar col[3];

            info->cp += xcf_read_int8 (info->fp, (guint8 *) col, 3);

            gimp_rgb_set_uchar (&(*channel)->color, col[0], col[1], col[2]);
          }
          break;

        case PROP_TATTOO:
          info->cp +=
            xcf_read_int32 (info->fp, &GIMP_ITEM (*channel)->tattoo, 1);
          break;

        case PROP_PARASITES:
          {
            glong         base = info->cp;
            GimpParasite *p;

            while ((info->cp - base) < prop_size)
              {
                p = xcf_load_parasite (info);
                gimp_item_parasite_attach (GIMP_ITEM (*channel), p);
                gimp_parasite_free (p);
              }
            if (info->cp - base != prop_size)
              g_message ("Error while loading a channel's parasites");
          }
          break;

        default:
#ifdef GIMP_UNSTABLE
          g_printerr ("unexpected/unknown channel property: %d (skipping)",
                      prop_type);
#endif

          {
            guint8 buf[16];
            guint amount;

            while (prop_size > 0)
              {
                amount = MIN (16, prop_size);
                info->cp += xcf_read_int8 (info->fp, buf, amount);
                prop_size -= MIN (16, amount);
              }
          }
          break;
        }
    }

  return FALSE;
}

static gboolean
xcf_load_prop (XcfInfo  *info,
               PropType *prop_type,
               guint32  *prop_size)
{
  info->cp += xcf_read_int32 (info->fp, (guint32 *) prop_type, 1);
  info->cp += xcf_read_int32 (info->fp, (guint32 *) prop_size, 1);
  return TRUE;
}

static GimpLayer *
xcf_load_layer (XcfInfo   *info,
                GimpImage *image)
{
  GimpLayer     *layer;
  GimpLayerMask *layer_mask;
  guint32        hierarchy_offset;
  guint32        layer_mask_offset;
  gboolean       apply_mask = TRUE;
  gboolean       edit_mask  = FALSE;
  gboolean       show_mask  = FALSE;
  gboolean       active;
  gboolean       floating;
  guint32        text_layer_flags = 0;
  gint           width;
  gint           height;
  gint           type;
  gboolean       is_fs_drawable;
  gchar         *name;

  /* check and see if this is the drawable the floating selection
   *  is attached to. if it is then we'll do the attachment in our caller.
   */
  is_fs_drawable = (info->cp == info->floating_sel_offset);

  /* read in the layer width, height, type and name */
  info->cp += xcf_read_int32 (info->fp, (guint32 *) &width, 1);
  info->cp += xcf_read_int32 (info->fp, (guint32 *) &height, 1);
  info->cp += xcf_read_int32 (info->fp, (guint32 *) &type, 1);
  info->cp += xcf_read_string (info->fp, &name, 1);

  /* create a new layer */
  layer = gimp_layer_new (image, width, height,
                          type, name, 255, GIMP_NORMAL_MODE);
  g_free (name);
  if (! layer)
    return NULL;

  /* read in the layer properties */
  if (! xcf_load_layer_props (info, image, layer,
                              &apply_mask, &edit_mask, &show_mask,
                              &text_layer_flags))
    goto error;

  /* call the evil text layer hack that might change our layer pointer */
  active   = (info->active_layer == layer);
  floating = (info->floating_sel == layer);

  if (gimp_text_layer_xcf_load_hack (&layer))
    {
      gimp_text_layer_set_xcf_flags (GIMP_TEXT_LAYER (layer),
                                     text_layer_flags);

      if (active)
        info->active_layer = layer;
      if (floating)
        info->floating_sel = layer;
    }

  /* read the hierarchy and layer mask offsets */
  info->cp += xcf_read_int32 (info->fp, &hierarchy_offset, 1);
  info->cp += xcf_read_int32 (info->fp, &layer_mask_offset, 1);

  /* read in the hierarchy */
  if (! xcf_seek_pos (info, hierarchy_offset, NULL))
    goto error;

  if (! xcf_load_hierarchy (info, GIMP_DRAWABLE (layer)->tiles))
    goto error;

  /* read in the layer mask */
  if (layer_mask_offset != 0)
    {
      if (! xcf_seek_pos (info, layer_mask_offset, NULL))
        goto error;

      layer_mask = xcf_load_layer_mask (info, image);
      if (! layer_mask)
        goto error;

      layer_mask->apply_mask = apply_mask;
      layer_mask->edit_mask  = edit_mask;
      layer_mask->show_mask  = show_mask;

      gimp_layer_add_mask (layer, layer_mask, FALSE);
    }

  /* attach the floating selection... */
  if (is_fs_drawable)
    info->floating_sel_drawable = GIMP_DRAWABLE (layer);

  return layer;

 error:
  g_object_unref (layer);
  return NULL;
}

static GimpChannel *
xcf_load_channel (XcfInfo   *info,
                  GimpImage *image)
{
  GimpChannel *channel;
  guint32      hierarchy_offset;
  gint         width;
  gint         height;
  gboolean     is_fs_drawable;
  gchar       *name;
  GimpRGB      color = { 0.0, 0.0, 0.0, GIMP_OPACITY_OPAQUE };

  /* check and see if this is the drawable the floating selection
   *  is attached to. if it is then we'll do the attachment in our caller.
   */
  is_fs_drawable = (info->cp == info->floating_sel_offset);

  /* read in the layer width, height and name */
  info->cp += xcf_read_int32 (info->fp, (guint32 *) &width, 1);
  info->cp += xcf_read_int32 (info->fp, (guint32 *) &height, 1);
  info->cp += xcf_read_string (info->fp, &name, 1);

  /* create a new channel */
  channel = gimp_channel_new (image, width, height, name, &color);
  g_free (name);
  if (!channel)
    return NULL;

  /* read in the channel properties */
  if (!xcf_load_channel_props (info, image, &channel))
    goto error;

  /* read the hierarchy and layer mask offsets */
  info->cp += xcf_read_int32 (info->fp, &hierarchy_offset, 1);

  /* read in the hierarchy */
  if (!xcf_seek_pos (info, hierarchy_offset, NULL))
    goto error;

  if (!xcf_load_hierarchy (info, GIMP_DRAWABLE (channel)->tiles))
    goto error;

  if (is_fs_drawable)
    info->floating_sel_drawable = GIMP_DRAWABLE (channel);

  return channel;

 error:
  g_object_unref (channel);
  return NULL;
}

static GimpLayerMask *
xcf_load_layer_mask (XcfInfo   *info,
                     GimpImage *image)
{
  GimpLayerMask *layer_mask;
  GimpChannel   *channel;
  guint32        hierarchy_offset;
  gint           width;
  gint           height;
  gboolean       is_fs_drawable;
  gchar         *name;
  GimpRGB        color = { 0.0, 0.0, 0.0, GIMP_OPACITY_OPAQUE };

  /* check and see if this is the drawable the floating selection
   *  is attached to. if it is then we'll do the attachment in our caller.
   */
  is_fs_drawable = (info->cp == info->floating_sel_offset);

  /* read in the layer width, height and name */
  info->cp += xcf_read_int32 (info->fp, (guint32 *) &width, 1);
  info->cp += xcf_read_int32 (info->fp, (guint32 *) &height, 1);
  info->cp += xcf_read_string (info->fp, &name, 1);

  /* create a new layer mask */
  layer_mask = gimp_layer_mask_new (image, width, height, name, &color);
  g_free (name);
  if (!layer_mask)
    return NULL;

  /* read in the layer_mask properties */
  channel = GIMP_CHANNEL (layer_mask);
  if (!xcf_load_channel_props (info, image, &channel))
    goto error;

  /* read the hierarchy and layer mask offsets */
  info->cp += xcf_read_int32 (info->fp, &hierarchy_offset, 1);

  /* read in the hierarchy */
  if (! xcf_seek_pos (info, hierarchy_offset, NULL))
    goto error;

  if (!xcf_load_hierarchy (info, GIMP_DRAWABLE (layer_mask)->tiles))
    goto error;

  /* attach the floating selection... */
  if (is_fs_drawable)
    info->floating_sel_drawable = GIMP_DRAWABLE (layer_mask);

  return layer_mask;

 error:
  g_object_unref (layer_mask);
  return NULL;
}

static gboolean
xcf_load_hierarchy (XcfInfo     *info,
                    TileManager *tiles)
{
  guint32 saved_pos;
  guint32 offset;
  guint32 junk;
  gint    width;
  gint    height;
  gint    bpp;

  info->cp += xcf_read_int32 (info->fp, (guint32 *) &width, 1);
  info->cp += xcf_read_int32 (info->fp, (guint32 *) &height, 1);
  info->cp += xcf_read_int32 (info->fp, (guint32 *) &bpp, 1);

  /* make sure the values in the file correspond to the values
   *  calculated when the TileManager was created.
   */
  if (width  != tile_manager_width (tiles)  ||
      height != tile_manager_height (tiles) ||
      bpp    != tile_manager_bpp (tiles))
    return FALSE;

  /* load in the levels...we make sure that the number of levels
   *  calculated when the TileManager was created is the same
   *  as the number of levels found in the file.
   */

  info->cp += xcf_read_int32 (info->fp, &offset, 1); /* top level */

  /* discard offsets for layers below first, if any.
   */
  do
    {
      info->cp += xcf_read_int32 (info->fp, &junk, 1);
    }
  while (junk != 0);

  /* save the current position as it is where the
   *  next level offset is stored.
   */
  saved_pos = info->cp;

  /* seek to the level offset */
  if (!xcf_seek_pos (info, offset, NULL))
    return FALSE;

  /* read in the level */
  if (!xcf_load_level (info, tiles))
    return FALSE;

  /* restore the saved position so we'll be ready to
   *  read the next offset.
   */
  if (!xcf_seek_pos (info, saved_pos, NULL))
    return FALSE;

  return TRUE;
}


static gboolean
xcf_load_level (XcfInfo     *info,
                TileManager *tiles)
{
  guint32 saved_pos;
  guint32 offset, offset2;
  guint ntiles;
  gint width;
  gint height;
  gint i;
  gint fail;
  Tile *previous;
  Tile *tile;

  info->cp += xcf_read_int32 (info->fp, (guint32 *) &width, 1);
  info->cp += xcf_read_int32 (info->fp, (guint32 *) &height, 1);

  if (width  != tile_manager_width  (tiles) ||
      height != tile_manager_height (tiles))
    return FALSE;

  /* read in the first tile offset.
   *  if it is '0', then this tile level is empty
   *  and we can simply return.
   */
  info->cp += xcf_read_int32 (info->fp, &offset, 1);
  if (offset == 0)
    return TRUE;

  /* Initialise the reference for the in-memory tile-compression
   */
  previous = NULL;

  ntiles = tiles->ntile_rows * tiles->ntile_cols;
  for (i = 0; i < ntiles; i++)
    {
      fail = FALSE;

      if (offset == 0)
        {
          g_message ("not enough tiles found in level");
          return FALSE;
        }

      /* save the current position as it is where the
       *  next tile offset is stored.
       */
      saved_pos = info->cp;

      /* read in the offset of the next tile so we can calculate the amount
         of data needed for this tile*/
      info->cp += xcf_read_int32 (info->fp, &offset2, 1);

      /* if the offset is 0 then we need to read in the maximum possible
         allowing for negative compression */
      if (offset2 == 0)
        offset2 = offset + TILE_WIDTH * TILE_WIDTH * 4 * 1.5;
                                        /* 1.5 is probably more
                                           than we need to allow */

      /* seek to the tile offset */
      if (! xcf_seek_pos (info, offset, NULL))
        return FALSE;

      /* get the tile from the tile manager */
      tile = tile_manager_get (tiles, i, TRUE, TRUE);

      /* read in the tile */
      switch (info->compression)
        {
        case COMPRESS_NONE:
          if (!xcf_load_tile (info, tile))
            fail = TRUE;
          break;
        case COMPRESS_RLE:
          if (!xcf_load_tile_rle (info, tile, offset2 - offset))
            fail = TRUE;
          break;
        case COMPRESS_ZLIB:
          g_error ("xcf: zlib compression unimplemented");
          fail = TRUE;
          break;
        case COMPRESS_FRACTAL:
          g_error ("xcf: fractal compression unimplemented");
          fail = TRUE;
          break;
        }

      if (fail)
        {
          tile_release (tile, TRUE);
          return FALSE;
        }

      /* To potentially save memory, we compare the
       *  newly-fetched tile against the last one, and
       *  if they're the same we copy-on-write mirror one against
       *  the other.
       */
      if (previous != NULL)
        {
          tile_lock (previous);
          if (tile_ewidth (tile) == tile_ewidth (previous) &&
              tile_eheight (tile) == tile_eheight (previous) &&
              tile_bpp (tile) == tile_bpp (previous) &&
              memcmp (tile_data_pointer (tile, 0, 0),
                      tile_data_pointer (previous, 0, 0),
                      tile_size (tile)) == 0)
            tile_manager_map (tiles, i, previous);
          tile_release (previous, FALSE);
        }
      tile_release (tile, TRUE);
      previous = tile_manager_get (tiles, i, FALSE, FALSE);

      /* restore the saved position so we'll be ready to
       *  read the next offset.
       */
      if (!xcf_seek_pos (info, saved_pos, NULL))
        return FALSE;

      /* read in the offset of the next tile */
      info->cp += xcf_read_int32 (info->fp, &offset, 1);
    }

  if (offset != 0)
    {
      g_message ("encountered garbage after reading level: %d", offset);
      return FALSE;
    }

  return TRUE;
}

static gboolean
xcf_load_tile (XcfInfo *info,
               Tile    *tile)
{
#ifdef SWAP_FROM_FILE

  if (!info->swap_num)
    {
      info->ref_count = g_new (int, 1);
      info->swap_num = tile_swap_add (info->filename,
                                      xcf_swap_func,
                                      info->ref_count);
    }

  tile->swap_num = info->swap_num;
  tile->swap_offset = info->cp;
  *info->ref_count += 1;

#else

  info->cp += xcf_read_int8 (info->fp, tile_data_pointer(tile, 0, 0),
                             tile_size (tile));

#endif

  return TRUE;
}

static gboolean
xcf_load_tile_rle (XcfInfo *info,
                   Tile    *tile,
                   int     data_length)
{
  guchar *data;
  guchar val;
  gint size;
  gint count;
  gint length;
  gint bpp;
  gint i, j;
  gint nmemb_read_successfully;
  guchar *xcfdata, *xcfodata, *xcfdatalimit;

  data = tile_data_pointer (tile, 0, 0);
  bpp = tile_bpp (tile);

  xcfdata = xcfodata = g_malloc (data_length);

  /* we have to use fread instead of xcf_read_* because we may be
     reading past the end of the file here */
  nmemb_read_successfully = fread ((gchar *) xcfdata, sizeof (gchar),
                                   data_length, info->fp);
  info->cp += nmemb_read_successfully;

  xcfdatalimit = &xcfodata[nmemb_read_successfully - 1];

  for (i = 0; i < bpp; i++)
    {
      data = (guchar *) tile_data_pointer (tile, 0, 0) + i;
      size = tile_ewidth (tile) * tile_eheight (tile);
      count = 0;

      while (size > 0)
        {
          if (xcfdata > xcfdatalimit)
            {
              goto bogus_rle;
            }

          val = *xcfdata++;

          length = val;
          if (length >= 128)
            {
              length = 255 - (length - 1);
              if (length == 128)
                {
                  if (xcfdata >= xcfdatalimit)
                    {
                      goto bogus_rle;
                    }

                  length = (*xcfdata << 8) + xcfdata[1];
                  xcfdata += 2;
                }

              count += length;
              size -= length;

              if (size < 0)
                {
                  goto bogus_rle;
                }

              if (&xcfdata[length-1] > xcfdatalimit)
                {
                  goto bogus_rle;
                }

              while (length-- > 0)
                {
                  *data = *xcfdata++;
                  data += bpp;
                }
            }
          else
            {
              length += 1;
              if (length == 128)
                {
                  if (xcfdata >= xcfdatalimit)
                    {
                      goto bogus_rle;
                    }

                  length = (*xcfdata << 8) + xcfdata[1];
                  xcfdata += 2;
                }

              count += length;
              size -= length;

              if (size < 0)
                {
                  goto bogus_rle;
                }

              if (xcfdata > xcfdatalimit)
                {
                  goto bogus_rle;
                }

              val = *xcfdata++;

              for (j = 0; j < length; j++)
                {
                  *data = val;
                  data += bpp;
                }
            }
        }
    }
  g_free (xcfodata);
  return TRUE;

 bogus_rle:
  if (xcfodata)
    g_free (xcfodata);
  return FALSE;
}

static GimpParasite *
xcf_load_parasite (XcfInfo *info)
{
  GimpParasite *p;

  p = g_new (GimpParasite, 1);
  info->cp += xcf_read_string (info->fp, &p->name, 1);
  info->cp += xcf_read_int32 (info->fp, &p->flags, 1);
  info->cp += xcf_read_int32 (info->fp, &p->size, 1);
  p->data = g_new (gchar, p->size);
  info->cp += xcf_read_int8 (info->fp, p->data, p->size);

  return p;
}

static gboolean
xcf_load_old_paths (XcfInfo   *info,
                    GimpImage *image)
{
  guint32      num_paths;
  guint32      last_selected_row;
  GimpVectors *active_vectors;

  info->cp += xcf_read_int32 (info->fp, &last_selected_row, 1);
  info->cp += xcf_read_int32 (info->fp, &num_paths, 1);

  while (num_paths-- > 0)
    xcf_load_old_path (info, image);

  active_vectors = (GimpVectors *)
    gimp_container_get_child_by_index (image->vectors, last_selected_row);

  if (active_vectors)
    gimp_image_set_active_vectors (image, active_vectors);

  return TRUE;
}

static gboolean
xcf_load_old_path (XcfInfo   *info,
                   GimpImage *image)
{
  gchar                  *name;
  guint32                 locked;
  guint8                  state;
  guint32                 closed;
  guint32                 num_points;
  guint32                 version; /* changed from num_paths */
  GimpTattoo              tattoo = 0;
  GimpVectors            *vectors;
  GimpVectorsCompatPoint *points;
  gint                    i;

  info->cp += xcf_read_string (info->fp, &name, 1);
  info->cp += xcf_read_int32  (info->fp, &locked, 1);
  info->cp += xcf_read_int8   (info->fp, &state, 1);
  info->cp += xcf_read_int32  (info->fp, &closed, 1);
  info->cp += xcf_read_int32  (info->fp, &num_points, 1);
  info->cp += xcf_read_int32  (info->fp, &version, 1);

  if (version == 2)
    {
      guint32 dummy;

      /* Had extra type field and points are stored as doubles */
      info->cp += xcf_read_int32 (info->fp, (guint32 *) &dummy, 1);
    }
  else if (version == 3)
    {
      guint32 dummy;

      /* Has extra tatto field */
      info->cp += xcf_read_int32 (info->fp, (guint32 *) &dummy,  1);
      info->cp += xcf_read_int32 (info->fp, (guint32 *) &tattoo, 1);
    }
  else if (version != 1)
    {
      g_warning ("Unknown path type. Possibly corrupt XCF file");

      return FALSE;
    }

  /* skip empty compatibility paths */
  if (num_points == 0)
    return FALSE;

  points = g_new0 (GimpVectorsCompatPoint, num_points);

  for (i = 0; i < num_points; i++)
    {
      if (version == 1)
        {
          gint32 x;
          gint32 y;

          info->cp += xcf_read_int32 (info->fp, &points[i].type, 1);
          info->cp += xcf_read_int32 (info->fp, (guint32 *) &x,  1);
          info->cp += xcf_read_int32 (info->fp, (guint32 *) &y,  1);

          points[i].x = x;
          points[i].y = y;
        }
      else
        {
          gfloat x;
          gfloat y;

          info->cp += xcf_read_int32 (info->fp, &points[i].type, 1);
          info->cp += xcf_read_float (info->fp, &x,              1);
          info->cp += xcf_read_float (info->fp, &y,              1);

          points[i].x = x;
          points[i].y = y;
        }
    }

  vectors = gimp_vectors_compat_new (image, name, points, num_points, closed);

  g_free (name);
  g_free (points);

  GIMP_ITEM (vectors)->linked = locked;

  if (tattoo)
    GIMP_ITEM (vectors)->tattoo = tattoo;

  gimp_image_add_vectors (image, vectors,
                          gimp_container_num_children (image->vectors));

  return TRUE;
}

static gboolean
xcf_load_vectors (XcfInfo   *info,
                  GimpImage *image)
{
  guint32      version;
  guint32      active_index;
  guint32      num_paths;
  GimpVectors *active_vectors;
  guint32      base;

#ifdef GIMP_XCF_PATH_DEBUG
  g_printerr ("xcf_load_vectors\n");
#endif

  base = info->cp;

  info->cp += xcf_read_int32  (info->fp, &version, 1);

  if (version != 1)
    {
      g_message ("Unknown vectors version: %d (skipping)", version);
      return FALSE;
    }

  info->cp += xcf_read_int32 (info->fp, &active_index, 1);
  info->cp += xcf_read_int32 (info->fp, &num_paths,    1);

#ifdef GIMP_XCF_PATH_DEBUG
  g_printerr ("%d paths (active: %d)\n", num_paths, active_index);
#endif

  while (num_paths-- > 0)
    if (! xcf_load_vector (info, image))
      return FALSE;

  active_vectors = (GimpVectors *)
    gimp_container_get_child_by_index (image->vectors, active_index);

  if (active_vectors)
    gimp_image_set_active_vectors (image, active_vectors);

#ifdef GIMP_XCF_PATH_DEBUG
  g_printerr ("xcf_load_vectors: loaded %d bytes\n", info->cp - base);
#endif
  return TRUE;
}

static gboolean
xcf_load_vector (XcfInfo   *info,
                 GimpImage *image)
{
  gchar       *name;
  GimpTattoo   tattoo = 0;
  guint32      visible;
  guint32      linked;
  guint32      num_parasites;
  guint32      num_strokes;
  GimpVectors *vectors;
  gint         i;

#ifdef GIMP_XCF_PATH_DEBUG
  g_printerr ("xcf_load_vector\n");
#endif

  info->cp += xcf_read_string (info->fp, &name,          1);
  info->cp += xcf_read_int32  (info->fp, &tattoo,        1);
  info->cp += xcf_read_int32  (info->fp, &visible,       1);
  info->cp += xcf_read_int32  (info->fp, &linked,        1);
  info->cp += xcf_read_int32  (info->fp, &num_parasites, 1);
  info->cp += xcf_read_int32  (info->fp, &num_strokes,   1);

#ifdef GIMP_XCF_PATH_DEBUG
  g_printerr ("name: %s, tattoo: %d, visible: %d, linked: %d, num_parasites %d, "
              "num_strokes %d\n",
              name, tattoo, visible, linked, num_parasites, num_strokes);
#endif

  vectors = gimp_vectors_new (image, name);

  GIMP_ITEM (vectors)->visible = visible ? TRUE : FALSE;
  GIMP_ITEM (vectors)->linked  = linked  ? TRUE : FALSE;

  if (tattoo)
    GIMP_ITEM (vectors)->tattoo = tattoo;

  for (i = 0; i < num_parasites; i++)
    {
      GimpParasite *parasite;

      parasite = xcf_load_parasite (info);

      if (! parasite)
        return FALSE;

      gimp_item_parasite_attach (GIMP_ITEM (vectors), parasite);
      gimp_parasite_free (parasite);
    }

  for (i = 0; i < num_strokes; i++)
    {
      guint32      stroke_type_id;
      guint32      closed;
      guint32      num_axes;
      guint32      num_control_points;
      guint32      type;
      gfloat       coords[6] = { 0.0, 0.0, 1.0, 0.5, 0.5, 0.5 };
      GimpStroke  *stroke;
      gint         j;

      GValueArray *control_points;
      GValue       value = { 0, };
      GimpAnchor   anchor;
      GType        stroke_type;

      g_value_init (&value, GIMP_TYPE_ANCHOR);

      info->cp += xcf_read_int32 (info->fp, &stroke_type_id,     1);
      info->cp += xcf_read_int32 (info->fp, &closed,             1);
      info->cp += xcf_read_int32 (info->fp, &num_axes,           1);
      info->cp += xcf_read_int32 (info->fp, &num_control_points, 1);

#ifdef GIMP_XCF_PATH_DEBUG
      g_printerr ("stroke_type: %d, closed: %d, num_axes %d, len %d\n",
                  stroke_type_id, closed, num_axes, num_control_points);
#endif

      switch (stroke_type_id)
        {
        case XCF_STROKETYPE_BEZIER_STROKE:
          stroke_type = GIMP_TYPE_BEZIER_STROKE;
          break;

        default:
          g_printerr ("skipping unknown stroke type\n");
          xcf_seek_pos (info,
                        info->cp + 4 * num_axes * num_control_points,
                        NULL);
          continue;
        }

      control_points = g_value_array_new (num_control_points);

      anchor.selected = FALSE;

      for (j = 0; j < num_control_points; j++)
        {
          info->cp += xcf_read_int32 (info->fp, &type, 1);
          info->cp += xcf_read_float (info->fp, coords, num_axes);

          anchor.type              = type;
          anchor.position.x        = coords[0];
          anchor.position.y        = coords[1];
          anchor.position.pressure = coords[2];
          anchor.position.xtilt    = coords[3];
          anchor.position.ytilt    = coords[4];
          anchor.position.wheel    = coords[5];

          g_value_set_boxed (&value, &anchor);
          g_value_array_append (control_points, &value);

#ifdef GIMP_XCF_PATH_DEBUG
          g_printerr ("Anchor: %d, (%f, %f, %f, %f, %f, %f)\n", type,
                      coords[0], coords[1], coords[2], coords[3],
                      coords[4], coords[5]);
#endif
        }

      g_value_unset (&value);

      stroke = g_object_new (stroke_type,
                             "closed",         closed,
                             "control-points", control_points,
                             NULL);

      gimp_vectors_stroke_add (vectors, stroke);
    }

  gimp_image_add_vectors (image, vectors,
                          gimp_container_num_children (image->vectors));

  return TRUE;
}

#ifdef SWAP_FROM_FILE

static gboolean
xcf_swap_func (gint      fd,
               Tile     *tile,
               gint      cmd,
               gpointer  user_data)
{
  gint bytes;
  gint err;
  gint nleft;
  gint *ref_count;

  switch (cmd)
    {
    case SWAP_IN:
      lseek (fd, tile->swap_offset, SEEK_SET);

      bytes = tile_size (tile);
      tile_alloc (tile);

      nleft = bytes;
      while (nleft > 0)
        {
          do {
            err = read (fd, tile->data + bytes - nleft, nleft);
          } while ((err == -1) && ((errno == EAGAIN) || (errno == EINTR)));

          if (err <= 0)
            {
              g_message ("unable to read tile data from xcf file: "
                         "%d ( %d ) bytes read", err, nleft);
              return FALSE;
            }

          nleft -= err;
        }
      break;

    case SWAP_OUT:
    case SWAP_DELETE:
    case SWAP_COMPRESS:
      ref_count = user_data;
      *ref_count -= 1;
      if (*ref_count == 0)
        {
          tile_swap_remove (tile->swap_num);
          g_free (ref_count);
        }

      tile->swap_num = 1;
      tile->swap_offset = -1;

      return TRUE;
    }

  return FALSE;
}

#endif