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// Copyright (c) the JPEG XL Project Authors. All rights reserved.
//
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
use std::{fmt::Debug, marker::PhantomData};
use crate::{error::Result, util::CACHE_LINE_BYTE_SIZE};
use super::{Rect, internal::RawImageBuffer};
pub struct OwnedRawImage {
// Safety invariant: all the accessible bytes of `self.data` are initialized, and
// belongs to a single allocation that lives until `self` is dropped.
// The data referenced by self.data was allocated by RawImageBuffer::try_allocate.
// `data.is_aligned(CACHE_LINE_BYTE_SIZE)` is true.
pub(super) data: RawImageBuffer,
offset: (usize, usize),
padding: (usize, usize),
}
impl OwnedRawImage {
pub fn new_zeroed_with_padding(
byte_size: (usize, usize),
offset: (usize, usize),
mut padding: (usize, usize),
) -> Result<Self> {
// Since RawImageBuffer::try_allocate will round up the length of a row to a cache line,
// might as well declare that as available padding space.
if !(padding.0 + byte_size.0).is_multiple_of(CACHE_LINE_BYTE_SIZE) {
padding.0 += CACHE_LINE_BYTE_SIZE - (padding.0 + byte_size.0) % CACHE_LINE_BYTE_SIZE;
}
Ok(Self {
// Safety note: the returned memory is initialized and part of a single allocation of
// the correct length.
data: RawImageBuffer::try_allocate(
(byte_size.0 + padding.0, byte_size.1 + padding.1),
false,
)?,
offset,
padding,
})
}
pub fn get_rect_including_padding_mut(&mut self, rect: Rect) -> RawImageRectMut<'_> {
RawImageRectMut {
// Safety note: we are lending exclusive ownership to RawImageRectMut.
data: self.data.rect(rect),
_ph: PhantomData,
}
}
pub fn get_rect_including_padding(&'_ self, rect: Rect) -> RawImageRect<'_> {
RawImageRect {
// Safety note: correctness ensured by the return value borrowing from `self`.
data: self.data.rect(rect),
_ph: PhantomData,
}
}
fn shift_rect(&self, rect: Rect) -> Rect {
if cfg!(debug_assertions) {
// Check the original rect is within the content size (without padding)
rect.check_within(self.byte_size());
}
Rect {
origin: (rect.origin.0 + self.offset.0, rect.origin.1 + self.offset.1),
size: rect.size,
}
}
pub fn get_rect_mut(&mut self, rect: Rect) -> RawImageRectMut<'_> {
self.get_rect_including_padding_mut(self.shift_rect(rect))
}
pub fn get_rect(&'_ self, rect: Rect) -> RawImageRect<'_> {
self.get_rect_including_padding(self.shift_rect(rect))
}
#[inline(always)]
pub fn row_mut(&mut self, row: usize) -> &mut [u8] {
let offset = self.offset;
let end = offset.0 + self.byte_size().0;
// SAFETY: we don't write uninit data to `row`, and we have ownership of the accessible
// bytes of `self.data`.
let row = &mut unsafe { self.data.row_mut(row + offset.1) }[offset.0..end];
// SAFETY: MaybeUninit<u8> and u8 have the same size and layout, and our safety invariant
// guarantees the data is initialized.
unsafe { std::slice::from_raw_parts_mut(row.as_mut_ptr() as *mut u8, row.len()) }
}
#[inline(always)]
pub fn row(&self, row: usize) -> &[u8] {
let offset = self.offset;
let end = offset.0 + self.byte_size().0;
// SAFETY: we have shared access to the accessible bytes of `self.data`.
let row = &unsafe { self.data.row(row + offset.1) }[offset.0..end];
// SAFETY: MaybeUninit<u8> and u8 have the same size and layout, and our safety invariant
// guarantees the data is initialized.
unsafe { std::slice::from_raw_parts(row.as_ptr() as *const u8, row.len()) }
}
pub fn byte_size(&self) -> (usize, usize) {
let size = self.data.byte_size();
(size.0 - self.padding.0, size.1 - self.padding.1)
}
pub fn byte_offset(&self) -> (usize, usize) {
self.offset
}
pub fn byte_padding(&self) -> (usize, usize) {
self.padding
}
pub fn try_clone(&self) -> Result<OwnedRawImage> {
Ok(Self {
// SAFETY: we own the data that self.data references, so it is all accessible.
// Moreover, it is initialized and try_clone creates a copy, so the resulting data is
// owned and initialized.
data: unsafe { self.data.try_clone()? },
offset: self.offset,
padding: self.padding,
})
}
}
impl Drop for OwnedRawImage {
fn drop(&mut self) {
// SAFETY: we own the data referenced by self.data, and it was allocated by
// RawImageBuffer::try_allocate.
unsafe {
self.data.deallocate();
}
}
}
#[derive(Clone, Copy)]
pub struct RawImageRect<'a> {
// Safety invariant: all the accessible bytes of `self.data` are initialized.
pub(super) data: RawImageBuffer,
_ph: PhantomData<&'a u8>,
}
impl<'a> RawImageRect<'a> {
#[inline(always)]
pub fn row(&self, row: usize) -> &[u8] {
// SAFETY: we have shared access to the accessible bytes of `self.data`.
let row = unsafe { self.data.row(row) };
// SAFETY: MaybeUninit<u8> and u8 have the same size and layout, and our safety invariant
// guarantees the data is initialized.
unsafe { std::slice::from_raw_parts(row.as_ptr() as *const u8, row.len()) }
}
pub fn rect(&self, rect: Rect) -> RawImageRect<'a> {
Self {
// Safety note: correctness ensured by the fact that the return value still borrows
// from the original data source.
data: self.data.rect(rect),
_ph: PhantomData,
}
}
pub fn byte_size(&self) -> (usize, usize) {
self.data.byte_size()
}
}
pub struct RawImageRectMut<'a> {
// Safety invariant: all the accessible bytes of `self.data` are initialized and we have
// exclusive access to them.
pub(super) data: RawImageBuffer,
_ph: PhantomData<&'a mut u8>,
}
impl<'a> RawImageRectMut<'a> {
#[inline(always)]
pub fn row(&mut self, row: usize) -> &mut [u8] {
// SAFETY: we don't write uninit data to `row`, and we have exclusive access to the accessible
// bytes of `self.data`.
let row = unsafe { self.data.row_mut(row) };
// SAFETY: MaybeUninit<u8> and u8 have the same size and layout, and our safety invariant
// guarantees the data is initialized.
unsafe { std::slice::from_raw_parts_mut(row.as_mut_ptr() as *mut u8, row.len()) }
}
pub fn rect_mut(&'_ mut self, rect: Rect) -> RawImageRectMut<'_> {
Self {
// Safety note: we are lending ownership to the returned RawImageRectMut, and Rust's
// type system ensures correctness.
data: self.data.rect(rect),
_ph: PhantomData,
}
}
pub fn as_rect(&'_ self) -> RawImageRect<'_> {
RawImageRect {
// Safety note: correctness ensured by the return value borrowing from self.
data: self.data,
_ph: PhantomData,
}
}
pub fn byte_size(&self) -> (usize, usize) {
self.data.byte_size()
}
}
impl Debug for OwnedRawImage {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
write!(f, "raw {}x{}", self.byte_size().0, self.byte_size().1)
}
}
impl Debug for RawImageRect<'_> {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
write!(f, "raw rect {}x{}", self.byte_size().0, self.byte_size().1)
}
}
impl Debug for RawImageRectMut<'_> {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
write!(
f,
"raw mutrect {}x{}",
self.byte_size().0,
self.byte_size().1
)
}
}