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use super::{DecodeError, EncodedImageError, ImageDecodePlan, ImageGroups, Preflight};
use crate::{
PayloadLimits,
image::{
BufferRequirements, DecodeRequest, DecodeUnitRef, DecodeUnits, EncodedImageView,
GroupPlanes, Region, RegionMemoryPlan, RegionUnits, SurfaceRequirements, UnitGroup,
units::ScalarProfile,
},
};
#[derive(Clone, Copy, Debug)]
pub(super) enum DecodeScope {
Whole,
Region,
}
impl DecodeScope {
pub(super) fn units<'a>(
self,
group: UnitGroup<'a>,
region: RegionMemoryPlan,
) -> PlannedUnits<'a> {
match self {
Self::Whole => PlannedUnits::Whole(group.iter()),
Self::Region => {
let query = match group.planes() {
GroupPlanes::Joint(_) => region.region(),
GroupPlanes::Plane(index) => {
region.plane_region(index).expect("selected plane")
}
};
PlannedUnits::Region(group.units_in(query).expect("exact source region"))
}
}
}
}
pub(super) enum PlannedUnits<'a> {
Whole(DecodeUnits<'a>),
Region(RegionUnits<'a>),
}
impl PlannedUnits<'_> {
fn work_bound(&self) -> u64 {
match self {
Self::Whole(_) => 0,
Self::Region(units) => units.work_bound(),
}
}
}
impl<'a> Iterator for PlannedUnits<'a> {
type Item = DecodeUnitRef<'a>;
fn next(&mut self) -> Option<Self::Item> {
match self {
Self::Whole(units) => units.next(),
Self::Region(units) => units.next(),
}
}
}
#[derive(Default)]
struct Checksums {
end: u32,
byte_len: u64,
}
impl Checksums {
fn verify(
&mut self,
image: EncodedImageView<'_>,
range: core::ops::Range<u32>,
preflight: &mut Preflight<'_>,
) -> Result<(), EncodedImageError> {
if range.end <= self.end {
return Ok(());
}
let media = image.media();
// Includes bounded section scans and both integrity index searches.
preflight.spend(u64::from(media.header().section_count()) * 2 + 64)?;
let plan = media
.data_check_plan(range.start.max(self.end)..range.end)
.map_err(EncodedImageError::Media)?;
preflight.spend(u64::from(plan.byte_len()))?;
let end = plan.covered_end().unwrap_or_else(|| {
let data = image.data.descriptor();
data.offset() + data.size()
});
let byte_len = u64::from(plan.byte_len());
plan.verify().map_err(EncodedImageError::Media)?;
self.end = end;
self.byte_len += byte_len;
Ok(())
}
}
impl<'a, 'g> ImageGroups<'a, 'g> {
/// Preflights selected scalar units and plans exact cropped reconstruction.
///
/// Source groups already have verified static coverage. Complete intersecting
/// units are decoded into reusable workspace, then only the requested sample
/// intersections are copied. Chroma boundaries are exact, not expanded.
/// Shared checksum partitions are verified once; whole-DATA integrity still
/// requires one complete DATA scan. Unselected coding syntax is not consumed.
/// No allocation or file I/O occurs. All failures precede final output writes.
///
/// ```
/// use mirx::{reader::PayloadLimits, types::{ByteAlignment, DataIntegrity}, coding::Rle, image::{
/// ColorDescription, CoverageBudget, EncodedImageAsset, EncodedImageView,
/// SampleLayout, SurfaceDescriptor, SurfaceRequirements, UnitGroup,
/// }};
/// let surface = SurfaceDescriptor::new(4, 2, SampleLayout::A8, ColorDescription::NONE).unwrap();
/// let data = [0x81, 10, 0x81, 20, 0x81, 30, 0x81, 40];
/// let groups = [UnitGroup::builder(surface, Rle::new().record(), &data)
/// .with_tiles(2, 1).build().unwrap()];
/// let bytes = EncodedImageAsset::from_groups(surface, &groups)
/// .with_integrity(DataIntegrity::Indexed(&[2, 4, 6, 8])).encode().unwrap();
/// let image = EncodedImageView::open(&bytes).unwrap();
/// let mut slots = [None];
/// let groups = image.groups_into(&mut slots, &mut CoverageBudget::new(100)).unwrap();
/// let plan = groups.decode_region_plan(surface.region(2, 0, 2, 2).unwrap(),
/// SurfaceRequirements::new().with_base_alignment(ByteAlignment::new(64).unwrap()).with_stride_multiple(64),
/// &PayloadLimits::EMBEDDED).unwrap();
/// assert_eq!(plan.unit_count(), 2);
/// assert_eq!(plan.input_byte_len(), 4);
/// assert_eq!(plan.checksum_byte_len(), 4);
/// assert_eq!(plan.workspace_requirements().byte_len(), 2);
/// #[repr(align(64))]
/// struct Output([u8; 128]);
/// let mut output = Output([0; 128]);
/// let mut workspace = [0; 2];
/// let decoded = plan.decode_into(&mut output.0, &mut workspace).unwrap();
/// assert_eq!(decoded.plane(0).unwrap().row(0).unwrap(), Some(&[20, 20][..]));
/// assert_eq!(decoded.plane(0).unwrap().row(1).unwrap(), Some(&[40, 40][..]));
/// ```
pub fn decode_region_plan(
self,
requested: Region,
requirements: SurfaceRequirements,
limits: &PayloadLimits,
) -> Result<ImageDecodePlan<'a, 'g>, DecodeError> {
self.decode_region_plan_for(requested, DecodeRequest::new(requirements), limits)
}
/// Preflights cropped reconstruction for explicit execution and memory policy.
pub fn decode_region_plan_for(
self,
requested: Region,
request: DecodeRequest,
limits: &PayloadLimits,
) -> Result<ImageDecodePlan<'a, 'g>, DecodeError> {
request
.validate_reconstruction()
.map_err(DecodeError::Request)?;
let mut preflight = Preflight::new(limits, self.len()).map_err(DecodeError::Image)?;
let memory = self
.image()
.surface()
.region_plan(requested, request.requirements())
.map_err(DecodeError::Memory)?;
preflight
.spend(u64::from(memory.memory_plan().byte_len()) + 2 * self.len() as u64)
.map_err(DecodeError::Image)?;
let mut workspace = 0;
let mut input_bytes = 0;
let mut input_alignment = crate::ByteAlignment::ONE;
let mut input_addresses_aligned = true;
let mut checksums = Checksums::default();
for (index, group) in self.iter().enumerate() {
let units = DecodeScope::Region.units(group, memory);
preflight
.spend(units.work_bound() * 2)
.map_err(DecodeError::Image)?;
let mut profile = None;
let base = self.image.data.descriptor().offset()
+ self
.image
.group_source()
.record(index)
.map_err(DecodeError::Image)?
.data_range()
.start;
for unit in units {
input_alignment = input_alignment.max(unit.input_alignment());
input_addresses_aligned &= unit.data_address_is_aligned();
preflight.add_units(1).map_err(DecodeError::Image)?;
let selected_profile = match profile {
Some(profile) => profile,
None => {
let value =
ScalarProfile::new(group.coding(), group.surface().sample_layout())
.map_err(|error| {
DecodeError::Image(EncodedImageError::Coding {
group: index,
error,
})
})?;
profile = Some(value);
value
}
};
let ordinal = group
.selection()
.position(unit.cell())
.expect("selected ordinal");
let unit_memory = preflight
.unit(index, ordinal, unit, selected_profile)
.map_err(DecodeError::Image)?;
workspace = workspace.max(unit_memory.byte_len());
input_bytes += unit.data().len() as u64;
let profile_work = selected_profile
.extra_work(unit_memory)
.expect("preflighted profile work");
preflight
.spend_replay(
unit.data().len(),
unit_memory.sample_byte_len(),
profile_work,
)
.map_err(DecodeError::Image)?;
let range = unit.data_range();
checksums
.verify(
self.image,
base + range.start..base + range.end,
&mut preflight,
)
.map_err(DecodeError::Image)?;
}
}
Ok(ImageDecodePlan {
groups: self,
memory,
scope: DecodeScope::Region,
request,
workspace: BufferRequirements::new(workspace, request.workspace_alignment())
.map_err(DecodeError::Memory)?,
units: preflight.total_units(),
work: preflight.work(),
input_bytes,
input_alignment,
input_addresses_aligned,
checksum_bytes: checksums.byte_len,
})
}
}
#[cfg(test)]
mod tests;