gmime/gmime-stream-null.c

   1 /* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
   2 /*  GMime
   3  *  Copyright (C) 2000-2012 Jeffrey Stedfast
   4  *
   5  *  This library is free software; you can redistribute it and/or
   6  *  modify it under the terms of the GNU Lesser General Public License
   7  *  as published by the Free Software Foundation; either version 2.1
   8  *  of the License, or (at your option) any later version.
   9  *
  10  *  This library is distributed in the hope that it will be useful,
  11  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  *  Lesser General Public License for more details.
  14  *
  15  *  You should have received a copy of the GNU Lesser General Public
  16  *  License along with this library; if not, write to the Free
  17  *  Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
  18  *  02110-1301, USA.
  19  */
  20
  21
  22 #ifdef HAVE_CONFIG_H
  23 #include <config.h>
  24 #endif
  25
  26 #include <string.h>
  27
  28 #include "gmime-stream-null.h"
  29
  30
  31 /**
  32  * SECTION: gmime-stream-null
  33  * @title: GMimeStreamNull
  34  * @short_description: A null stream
  35  * @see_also: #GMimeStream
  36  *
  37  * A #GMimeStream which has no real backing storage at all. This
  38  * stream is useful for dry-runs and can also be useful for
  39  * determining statistics on source data which can be written to
  40  * streams but cannot be read as a stream itself (e.g. a #GMimeObject
  41  * via g_mime_object_write_to_stream()).
  42  **/
  43
  44
  45 static void g_mime_stream_null_class_init (GMimeStreamNullClass *klass);
  46 static void g_mime_stream_null_init (GMimeStreamNull *stream, GMimeStreamNullClass *klass);
  47 static void g_mime_stream_null_finalize (GObject *object);
  48
  49 static ssize_t stream_read (GMimeStream *stream, char *buf, size_t len);
  50 static ssize_t stream_write (GMimeStream *stream, const char *buf, size_t len);
  51 static int stream_flush (GMimeStream *stream);
  52 static int stream_close (GMimeStream *stream);
  53 static gboolean stream_eos (GMimeStream *stream);
  54 static int stream_reset (GMimeStream *stream);
  55 static gint64 stream_seek (GMimeStream *stream, gint64 offset, GMimeSeekWhence whence);
  56 static gint64 stream_tell (GMimeStream *stream);
  57 static gint64 stream_length (GMimeStream *stream);
  58 static GMimeStream *stream_substream (GMimeStream *stream, gint64 start, gint64 end);
  59
  60
  61 static GMimeStreamClass *parent_class = NULL;
  62
  63
  64 GType
  65 g_mime_stream_null_get_type (void)
  66 {
  67         static GType type = 0;
  68
  69         if (!type) {
  70                 static const GTypeInfo info = {
  71                         sizeof (GMimeStreamNullClass),
  72                         NULL, /* base_class_init */
  73                         NULL, /* base_class_finalize */
  74                         (GClassInitFunc) g_mime_stream_null_class_init,
  75                         NULL, /* class_finalize */
  76                         NULL, /* class_data */
  77                         sizeof (GMimeStreamNull),
  78                         0,    /* n_preallocs */
  79                         (GInstanceInitFunc) g_mime_stream_null_init,
  80                 };
  81
  82                 type = g_type_register_static (GMIME_TYPE_STREAM, "GMimeStreamNull", &info, 0);
  83         }
  84
  85         return type;
  86 }
  87
  88
  89 static void
  90 g_mime_stream_null_class_init (GMimeStreamNullClass *klass)
  91 {
  92         GMimeStreamClass *stream_class = GMIME_STREAM_CLASS (klass);
  93         GObjectClass *object_class = G_OBJECT_CLASS (klass);
  94
  95         parent_class = g_type_class_ref (GMIME_TYPE_STREAM);
  96
  97         object_class->finalize = g_mime_stream_null_finalize;
  98
  99         stream_class->read = stream_read;
 100         stream_class->write = stream_write;
 101         stream_class->flush = stream_flush;
 102         stream_class->close = stream_close;
 103         stream_class->eos = stream_eos;
 104         stream_class->reset = stream_reset;
 105         stream_class->seek = stream_seek;
 106         stream_class->tell = stream_tell;
 107         stream_class->length = stream_length;
 108         stream_class->substream = stream_substream;
 109 }
 110
 111 static void
 112 g_mime_stream_null_init (GMimeStreamNull *stream, GMimeStreamNullClass *klass)
 113 {
 114         stream->written = 0;
 115         stream->newlines = 0;
 116 }
 117
 118 static void
 119 g_mime_stream_null_finalize (GObject *object)
 120 {
 121         G_OBJECT_CLASS (parent_class)->finalize (object);
 122 }
 123
 124
 125 static ssize_t
 126 stream_read (GMimeStream *stream, char *buf, size_t len)
 127 {
 128         memset (buf, 0, len);
 129
 130         stream->position += len;
 131
 132         return len;
 133 }
 134
 135 static ssize_t
 136 stream_write (GMimeStream *stream, const char *buf, size_t len)
 137 {
 138         GMimeStreamNull *null = (GMimeStreamNull *) stream;
 139         register const char *inptr = buf;
 140         const char *inend = buf + len;
 141
 142         while (inptr < inend) {
 143                 if (*inptr == '\n')
 144                         null->newlines++;
 145                 inptr++;
 146         }
 147
 148         null->written += len;
 149         stream->position += len;
 150
 151         return len;
 152 }
 153
 154 static int
 155 stream_flush (GMimeStream *stream)
 156 {
 157         return 0;
 158 }
 159
 160 static int
 161 stream_close (GMimeStream *stream)
 162 {
 163         return 0;
 164 }
 165
 166 static gboolean
 167 stream_eos (GMimeStream *stream)
 168 {
 169         return TRUE;
 170 }
 171
 172 static int
 173 stream_reset (GMimeStream *stream)
 174 {
 175         GMimeStreamNull *null = (GMimeStreamNull *) stream;
 176
 177         null->written = 0;
 178         null->newlines = 0;
 179
 180         return 0;
 181 }
 182
 183 static gint64
 184 stream_seek (GMimeStream *stream, gint64 offset, GMimeSeekWhence whence)
 185 {
 186         GMimeStreamNull *null = (GMimeStreamNull *) stream;
 187         gint64 bound_end;
 188
 189         bound_end = stream->bound_end != -1 ? stream->bound_end : null->written;
 190
 191         switch (whence) {
 192         case GMIME_STREAM_SEEK_SET:
 193                 stream->position = MIN (offset + stream->bound_start, bound_end);
 194                 break;
 195         case GMIME_STREAM_SEEK_END:
 196                 stream->position = MAX (offset + bound_end, 0);
 197                 break;
 198         case GMIME_STREAM_SEEK_CUR:
 199                 stream->position += offset;
 200                 if (stream->position < stream->bound_start)
 201                         stream->position = stream->bound_start;
 202                 else if (stream->position > bound_end)
 203                         stream->position = bound_end;
 204         }
 205
 206         return stream->position;
 207 }
 208
 209 static gint64
 210 stream_tell (GMimeStream *stream)
 211 {
 212         return stream->position;
 213 }
 214
 215 static gint64
 216 stream_length (GMimeStream *stream)
 217 {
 218         GMimeStreamNull *null = (GMimeStreamNull *) stream;
 219         gint64 bound_end;
 220
 221         bound_end = stream->bound_end != -1 ? stream->bound_end : null->written;
 222
 223         return bound_end - stream->bound_start;
 224 }
 225
 226 static GMimeStream *
 227 stream_substream (GMimeStream *stream, gint64 start, gint64 end)
 228 {
 229         GMimeStream *null;
 230
 231         null = g_object_newv (GMIME_TYPE_STREAM_NULL, 0, NULL);
 232         g_mime_stream_construct (null, start, end);
 233
 234         return null;
 235 }
 236
 237
 238 /**
 239  * g_mime_stream_null_new:
 240  *
 241  * Creates a new #GMimeStreamNull object.
 242  *
 243  * Returns: a new null stream (similar to /dev/null on Unix).
 244  **/
 245 GMimeStream *
 246 g_mime_stream_null_new (void)
 247 {
 248         GMimeStream *null;
 249
 250         null = g_object_newv (GMIME_TYPE_STREAM_NULL, 0, NULL);
 251         g_mime_stream_construct (null, 0, -1);
 252
 253         return null;
 254 }