Struct DatabaseHeader 

pub struct DatabaseHeader {

    pub page_size: PageSize,
    pub write_version: u8,
    pub read_version: u8,
    pub reserved_per_page: u8,
    pub change_counter: u32,
    pub page_count: u32,
    pub freelist_trunk: u32,
    pub freelist_count: u32,
    pub schema_cookie: u32,
    pub schema_format: u32,
    pub default_cache_size: i32,
    pub largest_root_page: u32,
    pub text_encoding: TextEncoding,
    pub user_version: u32,
    pub incremental_vacuum: u32,
    pub application_id: u32,
    pub version_valid_for: u32,
    pub sqlite_version: u32,
}

The 100-byte database file header layout.

This struct represents the parsed content of the first 100 bytes of a SQLite database file.

Fields

page_size: PageSize

Page size in bytes (stored as big-endian u16 at offset 16; value 1 means 65536).

write_version: u8

File format write version (1 = legacy, 2 = WAL).

read_version: u8

File format read version (1 = legacy, 2 = WAL).

reserved_per_page: u8

Reserved bytes per page (at offset 20).

change_counter: u32

File change counter (at offset 24).

page_count: u32

Total number of pages in the database file.

freelist_trunk: u32

Page number of the first freelist trunk page (0 if none).

freelist_count: u32

Total number of freelist pages.

schema_cookie: u32

Schema cookie (incremented on schema changes).

schema_format: u32

Schema format number (currently 4).

default_cache_size: i32

Default page cache size (from PRAGMA default_cache_size).

largest_root_page: u32

Largest root page number for auto-vacuum/incremental-vacuum (0 if not auto-vacuum).

text_encoding: TextEncoding

Database text encoding (1=UTF8, 2=UTF16le, 3=UTF16be).

user_version: u32

User version (from PRAGMA user_version).

incremental_vacuum: u32

Non-zero for incremental vacuum mode.

application_id: u32

Application ID (from PRAGMA application_id).

version_valid_for: u32

Version-valid-for number (the change counter value when the version number was stored).

sqlite_version: u32

SQLite version number that created the database.

Implementations

impl DatabaseHeader

pub fn from_bytes(buf: &[u8; 100]) -> Result<Self, DatabaseHeaderError>

Parse and validate a 100-byte database header.

pub const fn open_mode( &self, max_supported: u8, ) -> Result<DatabaseOpenMode, DatabaseHeaderError>

Compute the open mode implied by the header’s read/write version bytes.

pub const fn is_page_count_stale(&self) -> bool

Check whether the header-derived database size might be stale.

When version_valid_for != change_counter, header-derived fields like page_count may be stale and should be recomputed from the actual file size. This protects against partial header writes or external modification.

pub const fn page_count_from_file_size(&self, file_size: u64) -> Option<u32>

Compute the page count from the actual file size.

This should be used when is_page_count_stale() returns true. Returns None if the file size is not a multiple of the page size or would exceed u32::MAX pages.

pub fn write_to_bytes( &self, out: &mut [u8; 100], ) -> Result<(), DatabaseHeaderError>

Serialize this header into a 100-byte buffer.

pub fn to_bytes(&self) -> Result<[u8; 100], DatabaseHeaderError>

Serialize this header to bytes.

Trait Implementations

impl Clone for DatabaseHeader

fn clone(&self) -> DatabaseHeader

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for DatabaseHeader

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

Formats the value using the given formatter.

impl Default for DatabaseHeader

fn default() -> Self

Returns the “default value” for a type.

impl Eq for DatabaseHeader

impl PartialEq for DatabaseHeader

fn eq(&self, other: &DatabaseHeader) -> 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 StructuralPartialEq for DatabaseHeader