Struct rustdb::block::BlockStg

pub struct BlockStg { /* private fields */ }

Manages allocation and deallocation of numbered relocatable fixed size blocks from underlying Storage.

Blocks are numbered. A map of the physical location of each block is kept at the start of the storage (after the header).

Physical blocks can be relocated by adjusting the map entry to point to the new location.

On save, the map of free block numbers is processed and any associated physical blocks are freed.

When a physical block is freed, the last physical block is relocated to fill it.

Implementations

impl BlockStg

pub fn new(stg: Box<dyn Storage>, blk_cap: u64) -> Self

Construct BlockStg with specified underlying Storage and block capacity. For existing file, block capacity will be read from file header.

pub fn blk_cap(&self) -> u64

Get the block capacity.

pub fn nsz(&self) -> usize

Get size of block number in bytes.

pub fn is_new(&self) -> bool

Is this new storage.

pub fn new_block(&mut self) -> u64

Allocate a new block number.

pub fn drop_block(&mut self, bn: u64)

Release a block number ( no longer valid ).

pub fn write(&mut self, bn: u64, offset: u64, data: &[u8])

Write data to specified numbered block at specified offset.

pub fn write_data( &mut self, bn: u64, offset: u64, data: Data, s: usize, n: usize )

Write slice of Data to specified numbered block at specified offset.

pub fn read(&self, bn: u64, offset: u64, data: &mut [u8])

Read data from specified numbered block and offset.

pub fn set_rsvd(&mut self, rsvd: [u8; 16])

Set the reserved area in the storage header.

pub fn get_rsvd(&self) -> [u8; 16]

Get the reserved area from the storage header.

pub fn save(&mut self)

Save changes to underlying storage.

pub fn wait_complete(&self)

Wait for save to complete.