From 3325d89c50330769819788cf5f2aba1b30aa5a9b Mon Sep 17 00:00:00 2001
From: cxl <cxl@f0d560ea-af0d-0410-9eb7-867de7ffcac7>
Date: Tue, 17 Mar 2009 13:57:45 +0000
Subject: [PATCH] LazyUpdate reference example

git-svn-id: svn://ultimatepp.org/upp/trunk@968 f0d560ea-af0d-0410-9eb7-867de7ffcac7
---
 reference/LazyUpdate/LazyUpdate.cpp | 35 +++++++++++++++++++++++++++++
 reference/LazyUpdate/LazyUpdate.upp | 10 +++++++++
 reference/LazyUpdate/init           |  4 ++++
 3 files changed, 49 insertions(+)
 create mode 100644 reference/LazyUpdate/LazyUpdate.cpp
 create mode 100644 reference/LazyUpdate/LazyUpdate.upp
 create mode 100644 reference/LazyUpdate/init

diff --git a/reference/LazyUpdate/LazyUpdate.cpp b/reference/LazyUpdate/LazyUpdate.cpp
new file mode 100644
index 000000000..eaea63572
--- /dev/null
+++ b/reference/LazyUpdate/LazyUpdate.cpp
@@ -0,0 +1,35 @@
+#include <Core/Core.h>
+
+using namespace Upp;
+
+struct DblSum {
+	Vector<double> d;
+	mutable double sum;
+	LazyUpdate dirty;
+
+public:
+	void Add(double x) {
+		d.Add(x);
+		dirty.Invalidate();
+	}
+
+	double Sum() const {
+		if(dirty.BeginUpdate()) {
+			Vector<int> o = GetSortOrder(d);
+			sum = 0;
+			for(int i = 0; i < o.GetCount(); i++)
+				sum += d[o[i]];
+			dirty.EndUpdate();
+		}
+		return sum;
+	}
+};
+
+CONSOLE_APP_MAIN
+{
+	DblSum x;
+	x.Add(100);
+	for(int i = 0; i < 1000*1000; i++)
+		x.Add(1e-10);
+	Cout() << x.Sum() << "\n";
+}
diff --git a/reference/LazyUpdate/LazyUpdate.upp b/reference/LazyUpdate/LazyUpdate.upp
new file mode 100644
index 000000000..d33ffd48a
--- /dev/null
+++ b/reference/LazyUpdate/LazyUpdate.upp
@@ -0,0 +1,10 @@
+uses
+	Core;
+
+file
+	LazyUpdate.cpp;
+
+mainconfig
+	"" = "",
+	"" = "MT";
+
diff --git a/reference/LazyUpdate/init b/reference/LazyUpdate/init
new file mode 100644
index 000000000..a16b356f0
--- /dev/null
+++ b/reference/LazyUpdate/init
@@ -0,0 +1,4 @@
+#ifndef _LazyUpdate_icpp_init_stub
+#define _LazyUpdate_icpp_init_stub
+#include "Core/init"
+#endif