From f185bbf898ddeaadbe092d4709a8e963fd2550fc Mon Sep 17 00:00:00 2001
From: Sean Harvey <sean@silverstripe.com>
Date: Mon, 30 Nov 2009 22:00:23 +0000
Subject: [PATCH] FEATURE Added MultipleOf and Modulus methods to ViewableData
 - useful for templating work

git-svn-id: svn://svn.silverstripe.com/silverstripe/open/modules/sapphire/branches/2.4@94063 467b73ca-7a2a-4603-9d3b-597d59a354a9
---
 core/ViewableData.php       | 16 ++++++++++++++++
 tests/DataObjectSetTest.php | 24 +++++++++++++++++++++++-
 2 files changed, 39 insertions(+), 1 deletion(-)

diff --git a/core/ViewableData.php b/core/ViewableData.php
index 472861d21..d02b81426 100755
--- a/core/ViewableData.php
+++ b/core/ViewableData.php
@@ -620,7 +620,23 @@ class ViewableData extends Object implements IteratorAggregate {
 	public function TotalItems() {
 		return $this->iteratorTotalItems;
 	}
+
+	/**
+	 * Returns the modulus of the numerical position of the item in the data set.
+	 * The count starts from $startIndex, which defaults to 1.
+	 * @param int $Mod The number to perform Mod operation to.
+	 * @param int $startIndex Number to start count from.
+	 * @return int
+	 */
+	public function Modulus($mod, $startIndex = 1) {
+		return ($this->iteratorPos + $startIndex) % $mod;
+	}
 	
+	public function MultipleOf($factor, $offset = 1) {
+		return ($this->Modulus($factor, $offset) == 0);
+	}
+
+
 	// UTILITY METHODS -------------------------------------------------------------------------------------------------
 	
 	/**
diff --git a/tests/DataObjectSetTest.php b/tests/DataObjectSetTest.php
index 0dd5f8cf3..c94483c2f 100644
--- a/tests/DataObjectSetTest.php
+++ b/tests/DataObjectSetTest.php
@@ -69,7 +69,29 @@ class DataObjectSetTest extends SapphireTest {
 		$this->assertTrue($three->Odd());
 		$this->assertFalse($four->Odd());
 	}
-	
+
+	public function testMultipleOf() {
+		$comments = DataObject::get('PageComment', '', "\"ID\" ASC");
+		$commArr = $comments->toArray();
+		$multiplesOf3 = 0;
+		
+		foreach($comments as $comment) {
+			if($comment->MultipleOf(3)) {
+				$comment->IsMultipleOf3 = true;
+				$multiplesOf3++;
+			} else {
+				$comment->IsMultipleOf3 = false;
+			}
+		}
+		
+		$this->assertEquals(2, $multiplesOf3);
+		
+		$this->assertFalse($commArr[0]->IsMultipleOf3);
+		$this->assertFalse($commArr[1]->IsMultipleOf3);
+		$this->assertTrue($commArr[2]->IsMultipleOf3);
+		$this->assertTrue($commArr[5]->IsMultipleOf3);
+	}
+
 	/**
 	 * Test {@link DataObjectSet->Count()}
 	 */