Commit LivePathEffect branch to trunk!

(disabled extension/internal/bitmap/*.* in build.xml to fix compilation)

(bzr r3472)

1 files changed, 67 insertions, 0 deletions

diff --git a/src/2geom/choose.h b/src/2geom/choose.h
new file mode 100644
index 000000000..169d77c79
--- /dev/null
+++ b/src/2geom/choose.h
@@ -0,0 +1,67 @@
+/*
+ * choose.h
+ *
+ * Copyright 2006 Nathan Hurst <njh@mail.csse.monash.edu.au>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it either under the terms of the GNU Lesser General Public
+ * License version 2.1 as published by the Free Software Foundation
+ * (the "LGPL") or, at your option, under the terms of the Mozilla
+ * Public License Version 1.1 (the "MPL"). If you do not alter this
+ * notice, a recipient may use your version of this file under either
+ * the MPL or the LGPL.
+ *
+ * You should have received a copy of the LGPL along with this library
+ * in the file COPYING-LGPL-2.1; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ * You should have received a copy of the MPL along with this library
+ * in the file COPYING-MPL-1.1
+ *
+ * The contents of this file are subject to the Mozilla Public License
+ * Version 1.1 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ * http://www.mozilla.org/MPL/
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY
+ * OF ANY KIND, either express or implied. See the LGPL or the MPL for
+ * the specific language governing rights and limitations.
+ *
+ */
+
+#ifndef _CHOOSE_H
+#define _CHOOSE_H
+
+// XXX: Can we keep only the left terms easily? 
+// this would more than halve the array
+// row index becomes n2 = n/2, row2 = n2*(n2+1)/2, row = row2*2+(n&1)?n2:0
+// we could also leave off the ones
+
+template <typename T>
+T choose(unsigned n, unsigned k) {
+    static std::vector<T> pascals_triangle;
+    static unsigned rows_done = 0;
+    // indexing is (0,0,), (1,0), (1,1), (2, 0)...
+    // to get (i, j) i*(i+1)/2 + j
+    if(k < 0 || k > n) return 0;
+    if(rows_done <= n) {// we haven't got there yet
+        if(rows_done == 0) {
+            pascals_triangle.push_back(1);
+            rows_done = 1;
+        }
+        while(rows_done <= n) {
+            unsigned p = pascals_triangle.size() - rows_done;
+            pascals_triangle.push_back(1);
+            for(unsigned i = 0; i < rows_done-1; i++) {
+                pascals_triangle.push_back(pascals_triangle[p] 
+                                           + pascals_triangle[p+1]);
+		p++;
+            }
+            pascals_triangle.push_back(1);
+            rows_done ++;
+        }
+    }
+    unsigned row = (n*(n+1))/2;
+    return pascals_triangle[row+k];
+}
+
+#endif