use crate::{config::MAX_INLINE, marker_byte::Marker};
use core::{
slice::{from_raw_parts, from_raw_parts_mut},
str::{from_utf8_unchecked, from_utf8_unchecked_mut},
};
#[repr(C)]
pub(crate) struct InlineString {
pub(crate) marker: Marker,
pub(crate) data: [u8; MAX_INLINE],
}
impl Clone for InlineString {
fn clone(&self) -> Self {
unreachable!("InlineString should be copy!")
}
}
impl Copy for InlineString {}
impl InlineString {
pub(crate) const fn new() -> Self {
Self {
marker: Marker::empty(),
data: [0; MAX_INLINE],
}
}
pub(crate) fn set_size(&mut self, size: usize) {
self.marker.set_data(size as u8);
}
pub(crate) fn len(&self) -> usize {
let len = self.marker.data() as usize;
assert!(len <= MAX_INLINE);
len
}
pub(crate) fn as_slice(&self) -> &[u8] {
self.data.as_ref()
}
pub(crate) fn as_mut_slice(&mut self) -> &mut [u8] {
self.data.as_mut()
}
pub(crate) fn as_str(&self) -> &str {
unsafe {
let data = from_raw_parts(self.data.as_ref().as_ptr(), self.len());
from_utf8_unchecked(data)
}
}
pub(crate) fn as_mut_str(&mut self) -> &mut str {
unsafe {
let data = from_raw_parts_mut(self.data.as_mut().as_mut_ptr(), self.len());
from_utf8_unchecked_mut(data)
}
}
pub(crate) fn insert_bytes(&mut self, index: usize, bytes: &[u8]) {
assert!(self.as_str().is_char_boundary(index));
if bytes.is_empty() {
return;
}
let len = self.len();
unsafe {
let ptr = self.data.as_mut().as_mut_ptr();
if index != len {
ptr.add(index + bytes.len())
.copy_from(&self.data.as_ref()[index], len - index);
}
ptr.add(index)
.copy_from_nonoverlapping(bytes.as_ptr(), bytes.len());
}
self.set_size(len + bytes.len());
}
pub(crate) fn remove_bytes(&mut self, start: usize, end: usize) {
let len = self.len();
assert!(start <= end);
assert!(end <= len);
assert!(self.as_str().is_char_boundary(start));
assert!(self.as_str().is_char_boundary(end));
if start == end {
return;
}
if end < len {
unsafe {
let ptr = self.data.as_mut().as_mut_ptr();
ptr.add(start).copy_from(ptr.add(end), len - end);
}
}
self.set_size(len - (end - start));
}
}
impl From<&'_ [u8]> for InlineString {
fn from(bytes: &[u8]) -> Self {
let len = bytes.len();
debug_assert!(len <= MAX_INLINE);
let mut out = Self::new();
out.marker = Marker::new_inline(len as u8);
out.data.as_mut()[..len].copy_from_slice(bytes);
out
}
}