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