Struct rustdb::page::Page

pub struct Page {
    pub data: Data,
    pub pnum: u64,
    pub is_dirty: bool,
    pub count: usize,
    pub level: u8,
    pub node_size: usize,
    pub root: usize,
    pub first_page: u64,
    // some fields omitted
}

A page in a SortedFile. Note that left subtree has nodes that compare greater.

Fields

data: Data

Data storage.

pnum: u64

Page number in file where page is saved.

is_dirty: bool

Does page need to be saved to backing storage?

count: usize

Number of records currently stored in the page.

level: u8

Page level. 0 means a child page, more than 0 a parent page.

node_size: usize

Number of bytes required for each node.

root: usize

Root node for the page.

first_page: u64

First child page ( for a parent page ).

Implementations

impl Page

pub fn size(&self) -> usize

The size of the page in bytes.

pub fn new(rec_size: usize, level: u8, data: Data, pnum: u64) -> Page

Construct a new page.

pub fn write_header(&mut self)

Sets header and trailer data (if parent). Called just before page is saved to file.

pub fn full(&self, db: &DB) -> bool

Is the page full?

pub fn new_page(&self) -> Page

Construct a new empty page inheriting record size and level from self. Used when splitting a page that is full.

pub fn find_child(&self, db: &DB, r: &dyn Record) -> u64

Find child page number.

pub fn find_equal(&self, db: &DB, r: &dyn Record) -> usize

Returns node id of Record equal to r, or zero if no such node exists.

pub fn insert(&mut self, db: &DB, r: &dyn Record)

Insert a record into the page ( if the key is a duplicate, nothing happens, and the record is not saved ).

pub fn insert_page(&mut self, db: &DB, r: &dyn Record, cp: u64)

Insert a child page with specified key and number.

pub fn append_page(&mut self, r: &dyn Record, cp: u64)

Append a child page with specified key and number.

pub fn append_from(&mut self, from: &Page, x: usize)

Append record x from specified page to this page.

pub fn copy(&self, x: usize) -> Vec<u8>

Make a copy of a parent key record.

pub fn append_page_copy(&mut self, b: &[u8], cp: u64)

Append a copied parent key.

pub fn remove(&mut self, db: &DB, r: &dyn Record)

Remove record from this page.

pub fn rec_offset(&self, x: usize) -> usize

Offset of the client data for node x.

pub fn rec_size(&self) -> usize

The client data size.

pub fn left(&self, x: usize) -> usize

Get the left child node for node x. Result is zero if there is no child.

pub fn right(&self, x: usize) -> usize

Get the right child node for node x. Result is zero if there is no child.

pub fn child_page(&self, x: usize) -> u64

Get the child page number for node x in a parent page.

pub fn set_child_page(&mut self, x: usize, pnum: u64)

Set the child page for node x.

pub fn compare(&self, db: &DB, r: &dyn Record, x: usize) -> Ordering

Compare record data for node x with record r.

pub fn get_key(&self, db: &DB, x: usize, r: &dyn Record) -> Box<dyn Record>

Get record key for node x.

pub fn clear(&mut self)

pub fn drop_key(&self, db: &DB, x: usize, r: &dyn Record)

pub fn compress(&mut self, db: &DB)

Reduce page size using free nodes.