Struct BTreePageHeader 

pub struct BTreePageHeader {
    pub header_offset: usize,
    pub page_type: BTreePageType,
    pub first_freeblock: u16,
    pub cell_count: u16,
    pub cell_content_start: u32,
    pub fragmented_free_bytes: u8,
    pub right_most_child: Option<PageNumber>,
}

Parsed B-tree page header.

Fields

header_offset: usize

Offset within the page where the B-tree page header begins (0 normally, 100 for page 1).

page_type: BTreePageType

Page type.

first_freeblock: u16

Offset of the first freeblock in the freeblock list (0 if none).

cell_count: u16

Number of cells on this page.

cell_content_start: u32

Start of cell content area. A raw value of 0 decodes to 65536.

fragmented_free_bytes: u8

Count of fragmented free bytes on this page.

right_most_child: Option<PageNumber>

Right-most child page number for interior pages.

Implementations

impl BTreePageHeader

pub const fn header_size(self) -> usize

Size of the B-tree page header in bytes (8 for leaf, 12 for interior).

pub fn parse( page: &[u8], page_size: PageSize, reserved_per_page: u8, is_page1: bool, ) -> Result<Self, BTreePageError>

Parse a B-tree page header from a page buffer.

pub fn parse_cell_pointers( self, page: &[u8], page_size: PageSize, reserved_per_page: u8, ) -> Result<Vec<u16>, BTreePageError>

Parse the cell pointer array for this page.

pub fn parse_freeblocks( self, page: &[u8], page_size: PageSize, reserved_per_page: u8, ) -> Result<Vec<Freeblock>, BTreePageError>

Traverse and parse the freeblock list for this page.

pub fn write_empty_leaf_table( page: &mut [u8], header_offset: usize, usable_size: u32, )

Write an empty leaf-table B-tree page header into a buffer.

Sets up the 8-byte B-tree page header for an empty leaf table page (type 0x0D) with zero cells, suitable for sqlite_master or any newly created table root page.

header_offset is the byte offset of the B-tree header within the page buffer. For page 1 this must be DATABASE_HEADER_SIZE (100); for every other page it should be 0.

usable_size equals page_size − reserved_per_page. The cell content area offset is set to this value so that all usable space is available for future cell insertions.

pub fn write_empty_leaf_index( page: &mut [u8], header_offset: usize, usable_size: u32, )

Initialize an empty leaf index page (type 0x0A) with zero cells, suitable for a newly created index root page.

header_offset is the byte offset of the B-tree header within the page buffer (0 for all non-page-1 pages).

usable_size equals page_size − reserved_per_page.

Trait Implementations

impl Clone for BTreePageHeader

fn clone(&self) -> BTreePageHeader

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for BTreePageHeader

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Hash for BTreePageHeader

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq for BTreePageHeader

fn eq(&self, other: &BTreePageHeader) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Copy for BTreePageHeader

impl Eq for BTreePageHeader

impl StructuralPartialEq for BTreePageHeader