include/loaders/GP_Container.h

   1 /*****************************************************************************
   2  * This file is part of gfxprim library.                                     *
   3  *                                                                           *
   4  * Gfxprim is free software; you can redistribute it and/or                  *
   5  * modify it under the terms of the GNU Lesser General Public                *
   6  * License as published by the Free Software Foundation; either              *
   7  * version 2.1 of the License, or (at your option) any later version.        *
   8  *                                                                           *
   9  * Gfxprim is distributed in the hope that it will be useful,                *
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of            *
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU         *
  12  * Lesser General Public License for more details.                           *
  13  *                                                                           *
  14  * You should have received a copy of the GNU Lesser General Public          *
  15  * License along with gfxprim; if not, write to the Free Software            *
  16  * Foundation, Inc., 51 Franklin Street, Fifth Floor,                        *
  17  * Boston, MA  02110-1301  USA                                               *
  18  *                                                                           *
  19  * Copyright (C) 2009-2013 Cyril Hrubis <metan@ucw.cz>                       *
  20  *                                                                           *
  21  *****************************************************************************/
  22
  23  /*
  24
  25    Container is an abstraction for file formats that can include several images
  26    in one file. For example gif, tiff, apng, cbr, cbz, etc.
  27
  28   */
  29
  30 #ifndef LOADERS_GP_CONTAINER_H
  31 #define LOADERS_GP_CONTAINER_H
  32
  33 #include "core/GP_Pixmap.h"
  34 #include "core/GP_ProgressCallback.h"
  35
  36 #include "loaders/GP_DataStorage.h"
  37
  38 struct GP_Container;
  39
  40 enum GP_ContainerWhence {
  41         GP_CONT_FIRST,
  42         GP_CONT_LAST,
  43         GP_CONT_CUR,
  44 };
  45
  46 struct GP_ContainerOps {
  47         /*
  48          * Loads next image from container, use the inline function defined
  49          * below.
  50          */
  51         GP_Pixmap *(*LoadNext)(struct GP_Container *self,
  52                                 GP_ProgressCallback *callback);
  53
  54         /*
  55          * Just loads current image, does not advance to the next image.
  56          */
  57         int (*LoadEx)(struct GP_Container *self, GP_Pixmap **img,
  58                       GP_DataStorage *storage, GP_ProgressCallback *callback);
  59
  60         /*
  61          * Close callback, use the inline function defined below.
  62          */
  63         void (*Close)(struct GP_Container *self);
  64
  65         /*
  66          * Seeks to the offset from whence.
  67          *
  68          * Returns 0 on success, errno on failure.
  69          */
  70         int (*Seek)(struct GP_Container *self, int offset,
  71                     enum GP_ContainerWhence whence);
  72
  73         /*
  74          * Container type name.
  75          */
  76         const char *type;
  77 };
  78
  79 typedef struct GP_Container {
  80         /*
  81          * Image counter. This is set to number of images, or to -1 if number
  82          * of images in container is not known prior to parsing the whole
  83          * file.
  84          */
  85         unsigned int img_count;
  86
  87         /*
  88          * Current image counter, do not change from application.
  89          */
  90         unsigned int cur_img;
  91
  92         /*
  93          * Contains container callbacks
  94          */
  95         const struct GP_ContainerOps *ops;
  96
  97         char priv[];
  98 } GP_Container;
  99
 100 #define GP_CONTAINER_PRIV(c) ((void*)(c)->priv)
 101
 102 /*
 103  * Behaves just like GP_LoadImage, but takes pointer to opened container instead.
 104  */
 105 static inline GP_Pixmap *GP_ContainerLoadNext(GP_Container *self,
 106                                                GP_ProgressCallback *callback)
 107 {
 108         return self->ops->LoadNext(self, callback);
 109 }
 110
 111 /*
 112  * Just loads current image, does not advance to the next one.
 113  */
 114 int GP_ContainerLoadEx(GP_Container *self, GP_Pixmap **img,
 115                        GP_DataStorage *storage, GP_ProgressCallback *callback);
 116
 117 static inline GP_Pixmap *GP_ContainerLoad(GP_Container *self,
 118                                            GP_ProgressCallback *callback)
 119 {
 120         GP_Pixmap *ret = NULL;
 121
 122         GP_ContainerLoadEx(self, &ret, NULL, callback);
 123
 124         return ret;
 125 }
 126
 127 int GP_ContainerSeek(GP_Container *self, int offset,
 128                      enum GP_ContainerWhence whence);
 129
 130 static inline void GP_ContainerClose(GP_Container *self)
 131 {
 132         self->ops->Close(self);
 133 }
 134
 135 #endif /* LOADERS_GP_CONTAINER_H */