Struct CompactRecordHeader 

pub struct CompactRecordHeader {
    pub n_owned: u8,
    pub delete_mark: bool,
    pub min_rec: bool,
    pub heap_no: u16,
    pub rec_type: RecordType,
    pub next_offset: i16,
}

Parsed compact (new-style) record header.

In compact format, 5 bytes precede each record:

• Byte 0: info bits (delete mark, min_rec flag) + n_owned upper nibble
• Bytes 1-2: heap_no (13 bits) + rec_type (3 bits)
• Bytes 3-4: next record offset (signed, relative)

Fields

n_owned: u8

Number of records owned by this record in the page directory.

delete_mark: bool

Delete mark flag.

min_rec: bool

Min-rec flag (leftmost record on a non-leaf level).

heap_no: u16

Record’s position in the heap.

rec_type: RecordType

Record type.

next_offset: i16

Relative offset to the next record (signed).

Implementations

impl CompactRecordHeader

pub fn parse(data: &[u8]) -> Option<Self>

Parse a compact record header from the 5 bytes preceding the record origin.

data should point to the start of the 5-byte extra header.

Examples

use idb::innodb::record::{CompactRecordHeader, RecordType};
use byteorder::{BigEndian, ByteOrder};

let mut data = vec![0u8; 5];
// byte 0: info_bits(4) | n_owned(4)
//   delete_mark=1 (bit 5), n_owned=2 (bits 0-3) => 0x22
data[0] = 0x22;
// bytes 1-2: heap_no=7 (7<<3=56), rec_type=0 (Ordinary) => 56
BigEndian::write_u16(&mut data[1..3], 7 << 3);
// bytes 3-4: next_offset = 42
BigEndian::write_i16(&mut data[3..5], 42);

let hdr = CompactRecordHeader::parse(&data).unwrap();
assert_eq!(hdr.n_owned, 2);
assert!(hdr.delete_mark);
assert!(!hdr.min_rec);
assert_eq!(hdr.heap_no, 7);
assert_eq!(hdr.rec_type, RecordType::Ordinary);
assert_eq!(hdr.next_offset, 42);

Trait Implementations

impl Clone for CompactRecordHeader

fn clone(&self) -> CompactRecordHeader

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for CompactRecordHeader

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

Formats the value using the given formatter.