System.TPFS.Block
Contents
Description
Functions for dealing with TPFS blocks.
This is not a high level interface; it only provides a few utility functions
for dealing with the blocks on disk themselves. It does not deal with
extents or anything like that. See System.TPFS.Extent.
If you are looking for a high level interface, check out the modules for the the objects you are trying to access, as TPFS blocks simply contain these objects.
- type BlockIndex = Word64
- blockIndexToAddress :: Header -> BlockIndex -> Address
- addressToBlockIndex :: Header -> Address -> BlockIndex
- addressToBlockIndexAndOffset :: Header -> Address -> (BlockIndex, Word64)
- divBlocks :: Integral i => i -> Header -> i
- readBlock :: Device m h => Filesystem m h -> BlockIndex -> m ByteString
- writeBlock :: Device m h => Filesystem m h -> BlockIndex -> ByteString -> m ()
Indexing
type BlockIndex = Word64Source
blockIndexToAddress :: Header -> BlockIndex -> AddressSource
Converts a BlockIndex to an Address in the context of a filesystem.
addressToBlockIndex :: Header -> Address -> BlockIndexSource
Converts an Address to a Blockindex in the context of a filesystem.
Note: This function will floor any addresses to the block boundary; it does
not preserve offsets. See addressToBlockIndexAndOffset.
addressToBlockIndexAndOffset :: Header -> Address -> (BlockIndex, Word64)Source
Converts an Address to a BlockIndex and byte offset within the block
in the context of a filesystem.
Note: Undefined when the Address points to somewhere before the beginning
of the block space.
divBlocks :: Integral i => i -> Header -> iSource
Divides a number of bytes into the required number of blocks according to a filesystem header.
Reading and writing
readBlock :: Device m h => Filesystem m h -> BlockIndex -> m ByteStringSource
Reads an entire block into memory.
writeBlock :: Device m h => Filesystem m h -> BlockIndex -> ByteString -> m ()Source
Replaces a block with the given string. The string is truncated/padded with NULs to fit the filesystem's block size.