gstreamer/sources/custom/Iterator.cs

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// Iterator.cs - Custom iterator wrapper for IEnumerable
//
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// Authors:
// Maarten Bosmans <mkbosmans@gmail.com>
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// Sebastian Dröge <slomo@circular-chaos.org>
// Stephan Sundermann <stephansundermann@gmail.com>
//
// Copyright (c) 2009 Maarten Bosmans
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// Copyright (c) 2009 Sebastian Dröge
// Copyright (c) 2013 Stephan Sundermann
//
// This program is free software; you can redistribute it and/or
// modify it under the terms of version 2 of the Lesser GNU 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., 59 Temple Place - Suite 330,
// Boston, MA 02111-1307, USA.
namespace Gst {
using System;
using System.Collections;
using System.Collections.Generic;
using System.Runtime.InteropServices;
using GLib;
public partial class Iterator : IEnumerable {
[DllImport ("gobject-2.0-0.dll", CallingConvention = CallingConvention.Cdecl)]
static extern IntPtr g_value_reset (ref GLib.Value val);
[DllImport("gstreamer-1.0-0.dll", CallingConvention = CallingConvention.Cdecl)]
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static extern int gst_iterator_next(IntPtr raw, ref GLib.Value elem);
public Gst.IteratorResult Next(ref GLib.Value elem) {
int raw_ret = gst_iterator_next(Handle, ref elem);
Gst.IteratorResult ret = (Gst.IteratorResult) raw_ret;
return ret;
}
private class Enumerator : IEnumerator {
Iterator iterator;
Hashtable seen = new Hashtable ();
private object current = null;
public object Current {
get {
return current;
}
}
public bool MoveNext () {
IntPtr raw_ret;
bool retry = false;
if (iterator.Handle == IntPtr.Zero)
return false;
do {
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GLib.Value value = new GLib.Value (GLib.GType.Boolean);
value.Dispose ();
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IteratorResult ret = iterator.Next (ref value);
switch (ret) {
case IteratorResult.Done:
return false;
case IteratorResult.Ok:
if (seen.Contains (value)) {
retry = true;
break;
}
seen.Add (value , null);
current = value.Val;
return true;
case IteratorResult.Resync:
iterator.Resync ();
retry = true;
break;
default:
case IteratorResult.Error:
throw new Exception ("Error while iterating");
}
} while (retry);
return false;
}
public void Reset () {
seen.Clear ();
if (iterator.Handle != IntPtr.Zero)
iterator.Resync ();
}
public Enumerator (Iterator iterator) {
this.iterator = iterator;
}
}
private Enumerator enumerator = null;
public IEnumerator GetEnumerator () {
if (this.enumerator == null)
this.enumerator = new Enumerator (this);
return this.enumerator;
}
}
}