+
+ /**
+ * Advances to next "block" of bytes
+ *
+ * @return void
+ * @todo This method will load large but empty files in a whole
+ */
+ public function next () {
+ // Is there nothing to read?
+ if (!$this->valid()) {
+ // Nothing to read
+ return;
+ } // END - if
+
+ // Make sure the block instance is set
+ assert($this->getBlockInstance() instanceof CalculatableBlock);
+
+ // First calculate minimum block length
+ $length = $this->getBlockInstance()->caluclateMinimumBlockLength();
+
+ // Short be more than zero!
+ assert($length > 0);
+
+ // Wait until a entry/block separator has been found
+ $data = $this->getBackBuffer();
+ while ((!$this->isEndOfFileReached()) && (!$this->getBlockInstance()->isBlockSeparatorFound($data))) {
+ // Then read the block
+ $data .= $this->read($length);
+ //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput('data()=' . strlen($data));
+ } // END - if
+
+ // EOF reached?
+ if ($this->isEndOfFileReached()) {
+ // Set whole data as current block
+ //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput('Calling setCurrentBlock(' . strlen($data) . ') ...');
+ $this->setCurrentBlock($data);
+
+ // Then abort here silently
+ //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput('EOF reached.');
+ return;
+ } // END - if
+
+ /*
+ * Init back-buffer which is the data that has been found beyond the
+ * separator.
+ */
+ $this->initBackBuffer();
+
+ // Separate data
+ $dataArray = explode(self::getBlockSeparator(), $data);
+
+ // This array must contain two elements
+ //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput('dataArray=' . print_r($dataArray, TRUE));
+ assert(count($dataArray) == 2);
+
+ // Left part is the actual block, right one the back-buffer data
+ $this->setCurrentBlock($dataArray[0]);
+ $this->setBackBuffer($dataArray[1]);
+ }
+
+ /**
+ * Checks wether the current entry is valid (not at the end of the file).
+ * This method will return TRUE if an emptied (nulled) entry has been found.
+ *
+ * @return $isValid Whether the next entry is valid
+ */
+ public function valid () {
+ // Make sure the block instance is set
+ assert($this->getBlockInstance() instanceof CalculatableBlock);
+
+ // First calculate minimum block length
+ $length = $this->getBlockInstance()->caluclateMinimumBlockLength();
+
+ // Short be more than zero!
+ assert($length > 0);
+
+ // Get current seek position
+ $seekPosition = $this->key();
+
+ // Then try to read it
+ $data = $this->read($length);
+
+ // If some bytes could be read, all is fine
+ $isValid = ((is_string($data)) && (strlen($data) > 0));
+
+ // Get header size
+ $headerSize = $this->getBlockInstance()->getHeaderSize();
+
+ // Is the seek position at or beyond the header?
+ if ($seekPosition >= $headerSize) {
+ // Seek back to old position
+ $this->seek($seekPosition);
+ } else {
+ // Seek directly behind the header
+ $this->seek($headerSize);
+ }
+
+ // Return result
+ return $isValid;
+ }
projects / core.git / commitdiff