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/* vim: set sw=8: -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
/*
* gsf-input-proxy.c: proxy object (with its own current position)
*
* Copyright (C) 2004-2006 Morten Welinder (terra@gnome.org)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of version 2.1 of the GNU Lesser General Public
* License as published by the Free Software Foundation.
*
* 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 Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301
* USA
*/
#include <gsf-config.h>
#include <gsf/gsf-input-proxy.h>
#include <gsf/gsf.h>
static GObjectClass *parent_class;
struct _GsfInputProxy {
GsfInput input;
GsfInput *source;
gsf_off_t offset;
};
typedef struct {
GsfInputClass input_class;
} GsfInputProxyClass;
/**
* gsf_input_proxy_new_section:
* @source: The underlying data source.
* @offset: Offset into source for start of section.
* @size: Length of section.
*
* This creates a new proxy to a section of the given source. The new
* object will have its own current position, but any operation on it
* can change the source's position.
*
* If a proxy to a proxy is created, the intermediate proxy is short-
* circuited.
*
* This function will ref the source.
*
* Returns: a new input object.
**/
GsfInput *
gsf_input_proxy_new_section (GsfInput *source,
gsf_off_t offset,
gsf_off_t size)
{
GsfInputProxy *proxy;
gsf_off_t source_size;
g_return_val_if_fail (GSF_IS_INPUT (source), NULL);
g_return_val_if_fail (offset >= 0, NULL);
source_size = gsf_input_size (source);
g_return_val_if_fail (offset <= source_size, NULL);
g_return_val_if_fail (size <= source_size - offset, NULL);
proxy = g_object_new (GSF_INPUT_PROXY_TYPE, NULL);
proxy->offset = offset;
gsf_input_set_size (GSF_INPUT (proxy), size);
gsf_input_set_name (GSF_INPUT (proxy), gsf_input_name (source));
/* Short-circuit multiple proxies. */
if (GSF_IS_INPUT_PROXY (source)) {
GsfInputProxy *proxy_source = GSF_INPUT_PROXY (source);
proxy->offset += proxy_source->offset;
source = proxy_source->source;
}
proxy->source = g_object_ref (source);
return GSF_INPUT (proxy);
}
/**
* gsf_input_proxy_new:
* @source: The underlying data source.
*
* This creates a new proxy to the entire, given input source. See
* gsf_input_proxy_new_section for details.
*
* Returns: a new input object.
**/
GsfInput *
gsf_input_proxy_new (GsfInput *source)
{
return gsf_input_proxy_new_section (source, 0, gsf_input_size (source));
}
static void
gsf_input_proxy_finalize (GObject *obj)
{
GsfInputProxy *proxy = (GsfInputProxy *)obj;
if (proxy->source != NULL) {
g_object_unref (proxy->source);
proxy->source = NULL;
}
parent_class->finalize (obj);
}
static GsfInput *
gsf_input_proxy_dup (GsfInput *src_input, G_GNUC_UNUSED GError **err)
{
return gsf_input_proxy_new (src_input);
}
static guint8 const *
gsf_input_proxy_read (GsfInput *input, size_t num_bytes, guint8 *buffer)
{
GsfInputProxy *proxy = GSF_INPUT_PROXY (input);
/* Seek to our position in the source. */
if (gsf_input_seek (proxy->source,
proxy->offset + gsf_input_tell (input),
G_SEEK_SET))
return NULL;
/* Read the data. */
return gsf_input_read (proxy->source, num_bytes, buffer);
}
static gboolean
gsf_input_proxy_seek (G_GNUC_UNUSED GsfInput *input,
G_GNUC_UNUSED gsf_off_t offset,
G_GNUC_UNUSED GSeekType whence)
{
return FALSE;
}
static void
gsf_input_proxy_init (GObject *obj)
{
GsfInputProxy *proxy = GSF_INPUT_PROXY (obj);
proxy->source = NULL;
proxy->offset = 0;
}
static void
gsf_input_proxy_class_init (GObjectClass *gobject_class)
{
GsfInputClass *input_class = GSF_INPUT_CLASS (gobject_class);
gobject_class->finalize = gsf_input_proxy_finalize;
input_class->Dup = gsf_input_proxy_dup;
input_class->Read = gsf_input_proxy_read;
input_class->Seek = gsf_input_proxy_seek;
parent_class = g_type_class_peek_parent (gobject_class);
}
GSF_CLASS (GsfInputProxy, gsf_input_proxy,
gsf_input_proxy_class_init, gsf_input_proxy_init,
GSF_INPUT_TYPE)
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