public function __construct(FileInterface $file, ColumnSchema $columnPage) { $this->file = $file; $this->columnSchema = $columnPage; $cellSize = $columnPage->getCellSize(); if ($cellSize <= 1) { $this->cellLengthSize = 1; } else { $this->cellLengthSize = ceil(log($columnPage->getCellSize(), 256)); } assert($this->file->getLength() % $this->getPageSize() === 0); }