/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
/* camel-stream-fs.c : file system based stream
*
* Authors: Bertrand Guiheneuf <bertrand@helixcode.com>
* Michael Zucchi <notzed@helixcode.com>
*
* Copyright 1999, 2000 Helix Code, Inc. (http://www.helixcode.com)
*
* 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 "camel-seekable-substream.h"
static CamelSeekableStreamClass *parent_class = NULL;
/* Returns the class for a CamelSeekableSubStream */
#define CSS_CLASS(so) CAMEL_SEEKABLE_SUBSTREAM_CLASS (CAMEL_OBJECT(so)->klass)
static int stream_read (CamelStream *stream, char *buffer, unsigned int n);
static int stream_write (CamelStream *stream, const char *buffer, unsigned int n);
static int stream_flush (CamelStream *stream);
static int stream_close (CamelStream *stream);
static gboolean eos (CamelStream *stream);
static off_t stream_seek (CamelSeekableStream *stream, off_t offset,
CamelStreamSeekPolicy policy);
static void
camel_seekable_substream_class_init (CamelSeekableSubstreamClass *camel_seekable_substream_class)
{
CamelSeekableStreamClass *camel_seekable_stream_class =
CAMEL_SEEKABLE_STREAM_CLASS (camel_seekable_substream_class);
CamelStreamClass *camel_stream_class =
CAMEL_STREAM_CLASS (camel_seekable_substream_class);
parent_class = CAMEL_SEEKABLE_STREAM_CLASS (camel_type_get_global_classfuncs (camel_seekable_stream_get_type ()));
/* virtual method definition */
/* virtual method overload */
camel_stream_class->read = stream_read;
camel_stream_class->write = stream_write;
camel_stream_class->flush = stream_flush;
camel_stream_class->close = stream_close;
camel_stream_class->eos = eos;
camel_seekable_stream_class->seek = stream_seek;
}
static void
camel_seekable_substream_finalize (CamelObject *object)
{
CamelSeekableSubstream *seekable_substream =
CAMEL_SEEKABLE_SUBSTREAM (object);
if (seekable_substream->parent_stream)
camel_object_unref (CAMEL_OBJECT (seekable_substream->parent_stream));
}
CamelType
camel_seekable_substream_get_type (void)
{
static CamelType camel_seekable_substream_type = CAMEL_INVALID_TYPE;
if (camel_seekable_substream_type == CAMEL_INVALID_TYPE) {
camel_seekable_substream_type = camel_type_register (camel_seekable_stream_get_type (), "CamelSeekableSubstream",
sizeof (CamelSeekableSubstream),
sizeof (CamelSeekableSubstreamClass),
(CamelObjectClassInitFunc) camel_seekable_substream_class_init,
NULL,
NULL,
(CamelObjectFinalizeFunc) camel_seekable_substream_finalize);
}
return camel_seekable_substream_type;
}
/**
* camel_seekable_substream_new_with_seekable_stream_and_bounds:
* @parent_stream: a seekable parent stream
* @inf_bound: a lower bound
* @sup_bound: an upper bound
*
* Creates a new CamelSeekableSubstream that references the portion
* of @parent_stream from @inf_bound to @sup_bound. (If @sup_bound is
* #CAMEL_STREAM_UNBOUND, it references to the end of stream, even if
* the stream grows.)
*
* While the substream is open, the caller cannot assume anything about
* the current position of @parent_stream. After the substream has been
* closed, @parent_stream will stabilize again.
*
* Return value: the substream
**/
CamelStream *
camel_seekable_substream_new_with_seekable_stream_and_bounds (CamelSeekableStream *parent_stream,
off_t start, off_t end)
{
CamelSeekableSubstream *seekable_substream;
g_return_val_if_fail (CAMEL_IS_SEEKABLE_STREAM (parent_stream), NULL);
/* Create the seekable substream. */
seekable_substream = CAMEL_SEEKABLE_SUBSTREAM (camel_object_new (camel_seekable_substream_get_type ()));
/* Initialize it. */
seekable_substream->parent_stream = parent_stream;
camel_object_ref (CAMEL_OBJECT (parent_stream));
/* Set the bound of the substream. We can ignore any possible error
* here, because if we fail to seek now, it will try again later.
*/
camel_seekable_stream_set_bounds ((CamelSeekableStream *)seekable_substream, start, end);
return CAMEL_STREAM (seekable_substream);
}
static gboolean
parent_reset (CamelSeekableSubstream *seekable_substream, CamelSeekableStream *parent)
{
CamelSeekableStream *seekable_stream =
CAMEL_SEEKABLE_STREAM (seekable_substream);
if (camel_seekable_stream_tell (parent) == seekable_stream->position)
return TRUE;
return camel_seekable_stream_seek (parent, seekable_stream->position, CAMEL_STREAM_SET)
== seekable_stream->position;
}
static int
stream_read (CamelStream *stream, char *buffer, unsigned int n)
{
CamelSeekableStream *parent;
CamelSeekableStream *seekable_stream = CAMEL_SEEKABLE_STREAM (stream);
CamelSeekableSubstream *seekable_substream =
CAMEL_SEEKABLE_SUBSTREAM (stream);
int v;
if (n == 0)
return 0;
parent = seekable_substream->parent_stream;
/* Go to our position in the parent stream. */
if (!parent_reset (seekable_substream, parent)) {
stream->eos = TRUE;
return 0;
}
/* Compute how many bytes should be read. */
if (seekable_stream->bound_end != CAMEL_STREAM_UNBOUND)
n = MIN (seekable_stream->bound_end - seekable_stream->position, n);
if (n == 0) {
stream->eos = TRUE;
return 0;
}
v = camel_stream_read (CAMEL_STREAM (parent), buffer, n);
/* ignore <0 - it's an error, let the caller deal */
if (v > 0)
seekable_stream->position += v;
return v;
}
static int
stream_write (CamelStream *stream, const char *buffer, unsigned int n)
{
/* NOT VALID ON SEEKABLE SUBSTREAM */
/* Well, it's entirely valid, just not implemented */
g_warning ("CamelSeekableSubstream:: seekable substream doesn't "
"have a write method yet?\n");
return -1;
}
static int
stream_flush (CamelStream *stream)
{
/* NOT VALID ON SEEKABLE SUBSTREAM */
g_warning ("CamelSeekableSubstream:: seekable substream doesn't "
"have a flush method\n");
return -1;
}
static int
stream_close (CamelStream *stream)
{
/* we dont really want to close the substream ... */
return 0;
}
static gboolean
eos (CamelStream *stream)
{
CamelSeekableSubstream *seekable_substream =
CAMEL_SEEKABLE_SUBSTREAM (stream);
CamelSeekableStream *seekable_stream = CAMEL_SEEKABLE_STREAM (stream);
CamelSeekableStream *parent;
gboolean eos;
if (stream->eos)
eos = TRUE;
else {
parent = seekable_substream->parent_stream;
if (!parent_reset (seekable_substream, parent))
return TRUE;
eos = camel_stream_eos (CAMEL_STREAM (parent));
if (!eos && (seekable_stream->bound_end != CAMEL_STREAM_UNBOUND)) {
eos = seekable_stream->position >= seekable_stream->bound_end;
}
}
return eos;
}
static off_t
stream_seek (CamelSeekableStream *seekable_stream, off_t offset,
CamelStreamSeekPolicy policy)
{
CamelSeekableSubstream *seekable_substream =
CAMEL_SEEKABLE_SUBSTREAM (seekable_stream);
CamelStream *stream = CAMEL_STREAM (seekable_stream);
off_t real_offset = 0;
stream->eos = FALSE;
switch (policy) {
case CAMEL_STREAM_SET:
real_offset = offset;
break;
case CAMEL_STREAM_CUR:
real_offset = seekable_stream->position + offset;
break;
case CAMEL_STREAM_END:
real_offset = camel_seekable_stream_seek (seekable_substream->parent_stream,
offset,
CAMEL_STREAM_END);
if (real_offset == -1)
return -1;
break;
}
if (seekable_stream->bound_end != CAMEL_STREAM_UNBOUND)
real_offset = MIN (real_offset, seekable_stream->bound_end);
if (real_offset<seekable_stream->bound_start)
real_offset = seekable_stream->bound_start;
seekable_stream->position = real_offset;
return real_offset;
}
