camel/camel-seekable-stream.c

   1 /* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
   2
   3 /*
   4  *
   5  * Author :
   6  *  Bertrand Guiheneuf <bertrand@helixcode.com>
   7  *
   8  * Copyright 1999, 2000 Helix Code, Inc. (http://www.helixcode.com)
   9  *
  10  * This program is free software; you can redistribute it and/or
  11  * modify it under the terms of the GNU General Public License as
  12  * published by the Free Software Foundation; either version 2 of the
  13  * License, or (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  * GNU General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program; if not, write to the Free Software
  22  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
  23  * USA
  24  */
  25
  26
  27
  28 #include <config.h>
  29 #include "camel-seekable-stream.h"
  30
  31 static CamelStreamClass *parent_class=NULL;
  32
  33
  34 /* Returns the class for a CamelSeekableStream */
  35 #define CSS_CLASS(so) CAMEL_SEEKABLE_STREAM_CLASS (GTK_OBJECT(so)->klass)
  36
  37 static gint      _seek      (CamelSeekableStream *stream,
  38                              gint offset,
  39                              CamelStreamSeekPolicy policy);
  40 static void      _reset     (CamelStream *stream);
  41
  42
  43 static void
  44 camel_seekable_stream_class_init (CamelSeekableStreamClass *camel_seekable_stream_class)
  45 {
  46         CamelStreamClass *camel_stream_class = CAMEL_STREAM_CLASS (camel_seekable_stream_class);
  47
  48         parent_class = gtk_type_class (camel_stream_get_type ());
  49
  50         /* seekable stream methods */
  51         camel_seekable_stream_class->seek = _seek;
  52
  53         /* camel stream methods overload */
  54         camel_stream_class->reset = _reset;
  55 }
  56
  57 GtkType
  58 camel_seekable_stream_get_type (void)
  59 {
  60         static GtkType camel_seekable_stream_type = 0;
  61
  62         if (!camel_seekable_stream_type)        {
  63                 GtkTypeInfo camel_seekable_stream_info =
  64                 {
  65                         "CamelSeekableStream",
  66                         sizeof (CamelSeekableStream),
  67                         sizeof (CamelSeekableStreamClass),
  68                         (GtkClassInitFunc) camel_seekable_stream_class_init,
  69                         (GtkObjectInitFunc) NULL,
  70                                 /* reserved_1 */ NULL,
  71                                 /* reserved_2 */ NULL,
  72                         (GtkClassInitFunc) NULL,
  73                 };
  74
  75                 camel_seekable_stream_type = gtk_type_unique (camel_stream_get_type (), &camel_seekable_stream_info);
  76         }
  77
  78         return camel_seekable_stream_type;
  79 }
  80
  81
  82
  83
  84 static gint
  85 _seek (CamelSeekableStream *stream,
  86        gint offset,
  87        CamelStreamSeekPolicy policy)
  88 {
  89         g_warning ("CamelSeekableStream::seek called on default implementation \n");
  90         return -1;
  91 }
  92
  93
  94
  95 /**
  96  * camel_stream_seek:
  97  * @stream: a CamelStream object.
  98  * @offset: offset value
  99  * @policy: what to do with the offset
 100  *
 101  *
 102  *
 103  * Return value: new position, -1 if operation failed.
 104  **/
 105 gint
 106 camel_seekable_stream_seek (CamelSeekableStream *stream,
 107                             gint offset,
 108                             CamelStreamSeekPolicy policy)
 109 {
 110         return CSS_CLASS (stream)->seek (stream, offset, policy);
 111 }
 112
 113
 114
 115
 116 /**
 117  * camel_seekable_stream_get_current_position: get the position of a stream
 118  * @stream: seekable stream object
 119  *
 120  * Get the current position of a seekable stream.
 121  *
 122  * Return value: the position.
 123  **/
 124 guint32
 125 camel_seekable_stream_get_current_position  (CamelSeekableStream *stream)
 126 {
 127         return stream->cur_pos;
 128 }
 129
 130
 131
 132 /* a default implementation of reset for seekable streams */
 133 static void
 134 _reset (CamelStream *stream)
 135 {
 136         CamelSeekableStream *seekable_stream;
 137
 138         g_assert (stream);
 139         seekable_stream = CAMEL_SEEKABLE_STREAM (stream);
 140
 141         camel_seekable_stream_seek (seekable_stream, 0, CAMEL_STREAM_SET);
 142 }
 143
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