diff --git a/typo3/sysext/core/Documentation/Changelog/master/Feature-58621-FormatCaseViewHelper.rst b/typo3/sysext/core/Documentation/Changelog/master/Feature-58621-FormatCaseViewHelper.rst
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+++ b/typo3/sysext/core/Documentation/Changelog/master/Feature-58621-FormatCaseViewHelper.rst
@@ -0,0 +1,27 @@
+======================================
+Feature: #58621 - FormatCaseViewHelper
+======================================
+
+Description
+===========
+
+Add a format case view helper to change casing of strings.
+
+Possible modes are:
+* ``upper`` Transforms the input string to its uppercase representation
+* ``lower`` Transforms the input string to its lowercase representation
+* ``capital`` Transforms the input string to its first letter upper-cased
+* ``uncapital`` Transforms the input string to its first letter lower-cased
+
+
+.. code-block:: html
+
+ <f:format.case>Some Text with miXed case</f:format.case> renders "SOME TEXT WITH MIXED CASE"
+
+ <f:format.case mode="capital">someString</f:format.case> renders "SomeString"
+
+
+Impact
+======
+
+The new ViewHelper can be used in all new projects. There is no interference with any part of existing code.
\ No newline at end of file
diff --git a/typo3/sysext/fluid/Classes/ViewHelpers/Format/CaseViewHelper.php b/typo3/sysext/fluid/Classes/ViewHelpers/Format/CaseViewHelper.php
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index 0000000000000000000000000000000000000000..3af111fd576c87b460377f23781c5166e511d0ec
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+++ b/typo3/sysext/fluid/Classes/ViewHelpers/Format/CaseViewHelper.php
@@ -0,0 +1,160 @@
+<?php
+namespace TYPO3\CMS\Fluid\ViewHelpers\Format;
+
+/* *
+ * This script is backported from the TYPO3 Flow package "TYPO3.Fluid". *
+ * *
+ * It is free software; you can redistribute it and/or modify it under *
+ * the terms of the GNU Lesser General Public License, either version 3 *
+ * of the License, or (at your option) any later version. *
+ * *
+ * The TYPO3 project - inspiring people to share! *
+ * */
+
+use TYPO3\CMS\Fluid\Core\ViewHelper\AbstractViewHelper;
+use TYPO3\CMS\Fluid\Core\ViewHelper\Exception\InvalidVariableException;
+use TYPO3\CMS\Core\Charset\CharsetConverter;
+use TYPO3\CMS\Core\Utility\GeneralUtility;
+use TYPO3\CMS\Fluid\Core\ViewHelper\Facets\CompilableInterface;
+use TYPO3\CMS\Fluid\Core\Rendering\RenderingContextInterface;
+
+/**
+ * Modifies the case of an input string to upper- or lowercase or capitalization.
+ * The default transformation will be uppercase as in ``mb_convert_case`` [1].
+ *
+ * Possible modes are:
+ *
+ * ``lower``
+ * Transforms the input string to its lowercase representation
+ *
+ * ``upper``
+ * Transforms the input string to its uppercase representation
+ *
+ * ``capital``
+ * Transforms the input string to its first letter upper-cased, i.e. capitalization
+ *
+ * ``uncapital``
+ * Transforms the input string to its first letter lower-cased, i.e. uncapitalization
+ *
+ * ``capitalWords``
+ * Not supported yet: Transforms the input string to each containing word being capitalized
+ *
+ * Note that the behavior will be the same as in the appropriate PHP function ``mb_convert_case`` [1];
+ * especially regarding locale and multibyte behavior.
+ *
+ * @see http://php.net/manual/function.mb-convert-case.php [1]
+ *
+ * = Examples =
+ *
+ * <code title="Example">
+ * <f:format.case>Some Text with miXed case</f:format.case>
+ * </code>
+ * <output>
+ * SOME TEXT WITH MIXED CASE
+ * </output>
+ *
+ * <code title="Example with given mode">
+ * <f:format.case mode="capital">someString</f:format.case>
+ * </code>
+ * <output>
+ * SomeString
+ * </output>
+ *
+ * @api
+ */
+class CaseViewHelper extends AbstractViewHelper implements CompilableInterface {
+
+ /**
+ * Directs the input string being converted to "lowercase"
+ */
+ const CASE_LOWER = 'lower';
+
+ /**
+ * Directs the input string being converted to "UPPERCASE"
+ */
+ const CASE_UPPER = 'upper';
+
+ /**
+ * Directs the input string being converted to "Capital case"
+ */
+ const CASE_CAPITAL = 'capital';
+
+ /**
+ * Directs the input string being converted to "unCapital case"
+ */
+ const CASE_UNCAPITAL = 'uncapital';
+
+ /**
+ * Directs the input string being converted to "Capital Case For Each Word"
+ */
+ const CASE_CAPITAL_WORDS = 'capitalWords';
+
+ /**
+ * @var NULL|CharsetConverter
+ */
+ static protected $charsetConverter = NULL;
+
+ /**
+ * Changes the case of the input string
+ *
+ * @param string $value The input value. If not given, the evaluated child nodes will be used
+ * @param string $mode The case to apply, must be one of this' CASE_* constants. Defaults to uppercase application
+ * @return string the altered string.
+ * @api
+ */
+ public function render($value = NULL, $mode = self::CASE_UPPER) {
+ return self::renderStatic(
+ array(
+ 'value' => $value,
+ 'mode' => $mode,
+ ),
+ $this->buildRenderChildrenClosure(),
+ $this->renderingContext
+ );
+ }
+
+ /**
+ * Changes the case of the input string
+ *
+ * @param array $arguments
+ * @param \Closure $renderChildrenClosure
+ * @param RenderingContextInterface $renderingContext
+ * @return string
+ * @throws InvalidVariableException
+ */
+ static public function renderStatic(array $arguments, \Closure $renderChildrenClosure, RenderingContextInterface $renderingContext) {
+ $value = $arguments['value'];
+ $mode = $arguments['mode'];
+
+ if ($value === NULL) {
+ $value = $renderChildrenClosure();
+ }
+
+ if (is_null(static::$charsetConverter)) {
+ static::$charsetConverter = GeneralUtility::makeInstance(CharsetConverter::class);
+ }
+ $charsetConverter = static::$charsetConverter;
+
+ switch ($mode) {
+ case self::CASE_LOWER:
+ $output = $charsetConverter->conv_case('utf-8', $value, 'toLower');
+ break;
+ case self::CASE_UPPER:
+ $output = $charsetConverter->conv_case('utf-8', $value, 'toUpper');
+ break;
+ case self::CASE_CAPITAL:
+ $output = $charsetConverter->utf8_substr($charsetConverter->convCaseFirst('utf-8', $value, 'toUpper'), 0, 1) . $charsetConverter->utf8_substr($value, 1);
+ break;
+ case self::CASE_UNCAPITAL:
+ $output = $charsetConverter->utf8_substr($charsetConverter->convCaseFirst('utf-8', $value, 'toLower'), 0, 1) . $charsetConverter->utf8_substr($value, 1);
+ break;
+ case self::CASE_CAPITAL_WORDS:
+ // @todo: Implement method once there is a proper solution with using the CharsetConverter
+ default:
+ throw new InvalidVariableException('The case mode "' . $mode . '" supplied to Fluid\'s format.case ViewHelper is not supported.', 1358349150);
+ }
+
+ return $output;
+ }
+
+}
\ No newline at end of file
diff --git a/typo3/sysext/fluid/Tests/Unit/ViewHelpers/Format/CaseViewHelperTest.php b/typo3/sysext/fluid/Tests/Unit/ViewHelpers/Format/CaseViewHelperTest.php
new file mode 100644
index 0000000000000000000000000000000000000000..ce24e3df592ee1f5de129a953e864580946b090a
--- /dev/null
+++ b/typo3/sysext/fluid/Tests/Unit/ViewHelpers/Format/CaseViewHelperTest.php
@@ -0,0 +1,90 @@
+<?php
+namespace TYPO3\CMS\Fluid\Tests\Unit\ViewHelpers\Format;
+
+/* *
+ * This script is backported from the TYPO3 Flow package "TYPO3.Fluid". *
+ * *
+ * It is free software; you can redistribute it and/or modify it under *
+ * the terms of the GNU General Public License, either version 3 of the *
+ * License, or (at your option) any later version. *
+ * *
+ * The TYPO3 project - inspiring people to share! *
+ * */
+
+use TYPO3\CMS\Fluid\Tests\Unit\ViewHelpers\ViewHelperBaseTestcase;
+use TYPO3\CMS\Fluid\ViewHelpers\Format\CaseViewHelper;
+
+/**
+ * Test case
+ */
+class CaseViewHelperTest extends ViewHelperBaseTestcase {
+
+ /**
+ * @var CaseViewHelper|\PHPUnit_Framework_MockObject_MockObject
+ */
+ protected $subject;
+
+ public function setUp() {
+ parent::setUp();
+ $this->subject = $this->getMock(CaseViewHelper::class, array('renderChildren'));
+ $this->injectDependenciesIntoViewHelper($this->subject);
+ }
+
+ /**
+ * @test
+ */
+ public function viewHelperRendersChildrenIfGivenValueIsNull() {
+ $this->subject->expects($this->once())->method('renderChildren');
+ $this->subject->render();
+ }
+
+ /**
+ * @test
+ */
+ public function viewHelperDoesNotRenderChildrenIfGivenValueIsNotNull() {
+ $this->subject->expects($this->never())->method('renderChildren');
+ $this->subject->render('');
+ $this->subject->render(0);
+ $this->subject->render('foo');
+ }
+
+ /**
+ * @test
+ * @expectedException \TYPO3\CMS\Fluid\Core\ViewHelper\Exception\InvalidVariableException
+ */
+ public function viewHelperThrowsExceptionIfIncorrectModeIsGiven() {
+ $this->subject->render('Foo', 'incorrectMode');
+ }
+
+ /**
+ * @test
+ */
+ public function viewHelperConvertsUppercasePerDefault() {
+ $this->assertSame('FOOB4R', $this->subject->render('FooB4r'));
+ }
+
+ /**
+ * Signature: $input, $mode, $expected
+ */
+ public function conversionTestingDataProvider() {
+ return array(
+ array('FooB4r', CaseViewHelper::CASE_LOWER, 'foob4r'),
+ array('FooB4r', CaseViewHelper::CASE_UPPER, 'FOOB4R'),
+ array('foo bar', CaseViewHelper::CASE_CAPITAL, 'Foo bar'),
+ array('FOO Bar', CaseViewHelper::CASE_UNCAPITAL, 'fOO Bar'),
+ array('smørrebrød', CaseViewHelper::CASE_UPPER, 'SMØRREBRØD'),
+ array('smørrebrød', CaseViewHelper::CASE_CAPITAL, 'Smørrebrød'),
+ array('römtömtömtöm', CaseViewHelper::CASE_UPPER, 'RÖMTÖMTÖMTÖM'),
+ array('á¼Î»Î»Î¬Ï‚ α ω', CaseViewHelper::CASE_UPPER, 'á¼Î›Î›Î†Î£ Α Ω'),
+ );
+ }
+
+ /**
+ * @test
+ * @dataProvider conversionTestingDataProvider
+ */
+ public function viewHelperConvertsCorrectly($input, $mode, $expected) {
+ $this->assertSame($expected, $this->subject->render($input, $mode), sprintf('The conversion with mode "%s" did not perform as expected.', $mode));
+ }
+
+}