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use endian_scalar::read_scalar_at;
use follow::Follow;
use primitives::*;
#[derive(Debug)]
pub struct VTable<'a> {
buf: &'a [u8],
loc: usize,
}
impl<'a> PartialEq for VTable<'a> {
fn eq(&self, other: &VTable) -> bool {
self.as_bytes().eq(other.as_bytes())
}
}
impl<'a> VTable<'a> {
pub fn init(buf: &'a [u8], loc: usize) -> Self {
VTable {
buf: buf,
loc: loc,
}
}
pub fn num_fields(&self) -> usize {
(self.num_bytes() / SIZE_VOFFSET) - 2
}
pub fn num_bytes(&self) -> usize {
read_scalar_at::<VOffsetT>(self.buf, self.loc) as usize
}
pub fn object_inline_num_bytes(&self) -> usize {
let n = read_scalar_at::<VOffsetT>(self.buf, self.loc + SIZE_VOFFSET);
n as usize
}
pub fn get_field(&self, idx: usize) -> VOffsetT {
if idx > self.num_fields() {
return 0;
}
read_scalar_at::<VOffsetT>(
self.buf,
self.loc + SIZE_VOFFSET + SIZE_VOFFSET + SIZE_VOFFSET * idx,
)
}
pub fn get(&self, byte_loc: VOffsetT) -> VOffsetT {
if byte_loc as usize >= self.num_bytes() {
return 0;
}
read_scalar_at::<VOffsetT>(self.buf, self.loc + byte_loc as usize)
}
pub fn as_bytes(&self) -> &[u8] {
let len = self.num_bytes();
&self.buf[self.loc..self.loc + len]
}
}
#[allow(dead_code)]
pub fn field_index_to_field_offset(field_id: VOffsetT) -> VOffsetT {
let fixed_fields = 2;
((field_id + fixed_fields) * (SIZE_VOFFSET as VOffsetT)) as VOffsetT
}
#[allow(dead_code)]
pub fn field_offset_to_field_index(field_o: VOffsetT) -> VOffsetT {
debug_assert!(field_o >= 2);
let fixed_fields = 2;
(field_o / (SIZE_VOFFSET as VOffsetT)) - fixed_fields
}
impl<'a> Follow<'a> for VTable<'a> {
type Inner = VTable<'a>;
fn follow(buf: &'a [u8], loc: usize) -> Self::Inner {
VTable::init(buf, loc)
}
}