Add helper method for turning int|float into base-10 unsigned integer string.

lib/private/largefilehelper.php

@@ -12,6 +12,30 @@ namespace OC;
  * Helper class for large files on 32-bit platforms.
  */
 class LargeFileHelper {
+	/**
+	* @brief Formats a signed integer or float as an unsigned integer base-10
+	*        string. Passed strings will be checked for being base-10.
+	*
+	* @param int|float|string $number Number containing unsigned integer data
+	*
+	* @return string Unsigned integer base-10 string
+	*/
+	public function formatUnsignedInteger($number) {
+		if (is_float($number)) {
+			// Undo the effect of the php.ini setting 'precision'.
+			return number_format($number, 0, '', '');
+		} else if (is_string($number) && ctype_digit($number)) {
+			return $number;
+		} else if (is_int($number)) {
+			// Interpret signed integer as unsigned integer.
+			return sprintf('%u', $number);
+		} else {
+			throw new \UnexpectedValueException(
+				'Expected int, float or base-10 string'
+			);
+		}
+	}
+
 	/**
 	* @brief Tries to get the filesize of a file via various workarounds that
 	*        even work for large files on 32-bit platforms.

tests/lib/largefilehelper.php

@@ -0,0 +1,46 @@
+<?php
+/**
+ * Copyright (c) 2014 Andreas Fischer <bantu@owncloud.com>
+ * This file is licensed under the Affero General Public License version 3 or
+ * later.
+ * See the COPYING-README file.
+ */
+
+namespace Test;
+
+class LargeFileHelper extends \PHPUnit_Framework_TestCase {
+	protected $helper;
+
+	public function setUp() {
+		parent::setUp();
+		$this->helper = new \OC\LargeFileHelper;
+	}
+
+	public function testFormatUnsignedIntegerFloat() {
+		$this->assertSame(
+			'9007199254740992',
+			$this->helper->formatUnsignedInteger((float) 9007199254740992)
+		);
+	}
+
+	public function testFormatUnsignedIntegerInt() {
+		$this->assertSame(
+			PHP_INT_SIZE === 4 ? '4294967295' : '18446744073709551615',
+			$this->helper->formatUnsignedInteger(-1)
+		);
+	}
+
+	public function testFormatUnsignedIntegerString() {
+		$this->assertSame(
+			'9007199254740993',
+			$this->helper->formatUnsignedInteger('9007199254740993')
+		);
+	}
+
+	/**
+	* @expectedException \UnexpectedValueException
+	*/
+	public function testFormatUnsignedIntegerStringException() {
+		$this->helper->formatUnsignedInteger('900ABCD254740993');
+	}
+}