use std::mem;
use diskformat::*;
#[ derive (Copy, Clone, Debug, Eq, Hash, PartialEq) ]
pub struct BtrfsExtentItem <'a> {
header: & 'a BtrfsLeafItemHeader,
data_bytes: & 'a [u8],
}
#[ repr (C, packed) ]
#[ derive (Copy, Clone, Debug, Eq, Hash, PartialEq) ]
pub struct BtrfsExtentItemData {
reference_count: u64,
generation: u64,
flags: u64,
first_entry_key: BtrfsKey,
level: u8,
}
impl <'a> BtrfsExtentItem <'a> {
pub fn from_bytes (
header: & 'a BtrfsLeafItemHeader,
data_bytes: & 'a [u8],
) -> Result <BtrfsExtentItem <'a>, String> {
let extent_item =
BtrfsExtentItem {
header: header,
data_bytes: data_bytes,
};
if data_bytes.len () != mem::size_of::<BtrfsExtentItemData> () {
return Err (
format! (
"Must be exactly 0x{:x} bytes",
mem::size_of::<BtrfsExtentItemData> ()));
}
Ok (extent_item)
}
pub fn header (& self) -> & BtrfsLeafItemHeader {
self.header
}
pub fn object_id (& self) -> u64 {
self.header.object_id ()
}
pub fn key (& self) -> BtrfsKey {
self.header.key ()
}
pub fn offset (& self) -> u64 {
self.header.key ().offset ()
}
pub fn data (& self) -> & BtrfsExtentItemData {
unsafe {
& * (
self.data_bytes.as_ptr ()
as * const BtrfsExtentItemData
)
}
}
pub fn reference_count (& self) -> u64 {
self.data ().reference_count
}
pub fn generation (& self) -> u64 {
self.data ().generation
}
pub fn flags (& self) -> u64 {
self.data ().flags
}
pub fn first_entry_key (& self) -> BtrfsKey {
self.data ().first_entry_key
}
pub fn level (& self) -> u8 {
self.data ().level
}
}