Update OFFSET

Fix #4376.

Author: oleibman

src/PhpSpreadsheet/Calculation/LookupRef/Offset.php

@@ -7,6 +7,7 @@
 use PhpOffice\PhpSpreadsheet\Calculation\Information\ExcelError;
 use PhpOffice\PhpSpreadsheet\Cell\Cell;
 use PhpOffice\PhpSpreadsheet\Cell\Coordinate;
+use PhpOffice\PhpSpreadsheet\Worksheet\Validations;
 use PhpOffice\PhpSpreadsheet\Worksheet\Worksheet;
 
 class Offset
@@ -55,19 +56,22 @@ public static function OFFSET(?string $cellAddress = null, mixed $rows = 0, mixe
         if (!is_object($cell)) {
             return ExcelError::REF();
         }
+        $sheet = $cell->getParent()?->getParent(); // worksheet
+        if ($sheet !== null) {
+            $cellAddress = Validations::definedNameToCoordinate($cellAddress, $sheet);
+        }
 
         [$cellAddress, $worksheet] = self::extractWorksheet($cellAddress, $cell);
 
         $startCell = $endCell = $cellAddress;
         if (strpos($cellAddress, ':')) {
             [$startCell, $endCell] = explode(':', $cellAddress);
         }
-        [$startCellColumn, $startCellRow] = Coordinate::coordinateFromString($startCell);
-        [$endCellColumn, $endCellRow] = Coordinate::coordinateFromString($endCell);
+        [$startCellColumn, $startCellRow] = Coordinate::indexesFromString($startCell);
+        [, $endCellRow, $endCellColumn] = Coordinate::indexesFromString($endCell);
 
         $startCellRow += $rows;
-        $startCellColumn = Coordinate::columnIndexFromString($startCellColumn) - 1;
-        $startCellColumn += $columns;
+        $startCellColumn += $columns - 1;
 
         if (($startCellRow <= 0) || ($startCellColumn < 0)) {
             return ExcelError::REF();

tests/PhpSpreadsheetTests/Calculation/Functions/LookupRef/OffsetTest.php

@@ -74,4 +74,14 @@ public function testOffsetNamedRangeApostropheSheet(): void
 
         self::assertSame(2, $workSheet->getCell('B2')->getCalculatedValue());
     }
+
+    public function testOffsetMultiCellNamedRange(): void
+    {
+        $sheet = $this->getSheet();
+        $sheet->setCellValue('D13', 'Hello');
+        $this->getSpreadsheet()
+            ->addNamedRange(new NamedRange('CELLAREA', $sheet, '$B$6:$F$22'));
+        $sheet->setCellValue('D1', '=OFFSET(CELLAREA,7,2,1,1)');
+        self::assertSame('Hello', $sheet->getCell('D1')->getCalculatedValue());
+    }
 }