Paranoid::IO::FileMultiplexer::Block3pm

new

    $obj = Paranoid::IO::FileMultiplexer::Block->new(
            $filename, $bnum, $bsize);

This creates a new instance of a block object. It requires the filename in order to retrieve the cached file handle from Paranoid::IO, the number of the block (using zero-based indexing), and the size of the block. It will block size and the block number to calculate its actual position within the file.

blockNum

    $bn = $obj->blockNum;

This method returns the object's assigned block number.

blockSize

    $bs = $obj->blockSize;

This method returns the object's assigned block size.

minPos

    $minp = $obj->minPos;

This method returns the minimum file position for the block.

maxPos

    $maxp = $obj->maxPos;

This method returns the maximum file position for the block.

allocate

    $rv = $obj->allocate;

This method attempts to allocate the block on the file system, and returns a boolean indicating its success. This method will fail if you attempt to allocate a block that's already been allocated, or a block whose file position is beyond the current end of the file. In other words, blocks must be allocated in sequence.

recalibrate

    $rv = $obj->recalibrate;

This method recalculates minimum/maximum file position based on the currently set block size. This should always be called after any change to blockSize.

bwrite

    $bytesWritten = $obj->bwrite($content);
    $bytesWritten = $obj->bwrite($content, $start );
    $bytesWritten = $obj->bwrite($content, $start, $length );
    $bytesWritten = $obj->bwrite($content, $start, $length, $offset );

This method writes the passed content to the block, while making sure that the content does not overflow the block boundaries. If the start position of the write is omitted, it writes from the beginning of the block. If the start position is provided, note that this is the position relative to the block, not the file. That means you would specify values from a range of o to (blockSize - 1).

This method is intentionally designed to allow you to pass more content than will fit inside of a block, and yet only write as much as will fit within the block. The calling code should use the return value to figure out what remains to be written in other blocks, as needed.

bread

    $bytesRead = $obj->bread(\$content);
    $bytesRead = $obj->bread(\$content, $start);
    $bytesRead = $obj->bread(\$content, undef, $bytes);
    $bytesRead = $obj->bread(\$content, $start, $bytes);

This method reads the content of the block, while making sure that the content read does not go beyond the borders of the block. If the start position of the read is omitted, it reads from the beginning of the block. Like bwrite, this position is relative to the beginning of the block, not the file.

This method is also intentionally designed to allow you to request more data than can fit within the block, yet returning only what the block contains. The calling code should use the return value to figure out what remains to be read from other blocks, as needed.