OC\Files\Stream\Encryption::stream_write()

Complexity

Conditions	6
Paths	4

Size

Total Lines	49
Code Lines	28

Duplication

Lines	0
Ratio	0 %

Importance

Changes

0

<?php
	public function stream_write($data) {
		$length = 0;
		// loop over $data to fit it in 6126 sized unencrypted blocks
		while (isset($data[0])) {
			$remainingLength = strlen($data);

			// set the cache to the current 6126 block
			$this->readCache();

			// for seekable streams the pointer is moved back to the beginning of the encrypted block
			// flush will start writing there when the position moves to another block
			$positionInFile = (int)floor($this->position / $this->unencryptedBlockSize) *
				$this->util->getBlockSize() + $this->headerSize;
			$resultFseek = $this->parentStreamSeek($positionInFile);

			// only allow writes on seekable streams, or at the end of the encrypted stream
			if (!$this->readOnly && ($resultFseek || $positionInFile === $this->size)) {

				// switch the writeFlag so flush() will write the block
				$this->writeFlag = true;
				$this->fileUpdated = true;

				// determine the relative position in the current block
				$blockPosition = ($this->position % $this->unencryptedBlockSize);
				// check if $data fits in current block
				// if so, overwrite existing data (if any)
				// update position and liberate $data
				if ($remainingLength < ($this->unencryptedBlockSize - $blockPosition)) {
					$this->cache = substr($this->cache, 0, $blockPosition)
						. $data . substr($this->cache, $blockPosition + $remainingLength);
					$this->position += $remainingLength;
					$length += $remainingLength;
					$data = '';
					// if $data doesn't fit the current block, the fill the current block and reiterate
					// after the block is filled, it is flushed and $data is updatedxxx
				} else {
					$this->cache = substr($this->cache, 0, $blockPosition) .
						substr($data, 0, $this->unencryptedBlockSize - $blockPosition);
					$this->flush();
					$this->position += ($this->unencryptedBlockSize - $blockPosition);
					$length += ($this->unencryptedBlockSize - $blockPosition);
					$data = substr($data, $this->unencryptedBlockSize - $blockPosition);
				}
			} else {
				$data = '';
			}
			$this->unencryptedSize = max($this->unencryptedSize, $this->position);
		}
		return $length;
	}