use super::{ContainerHeader, ReadError, Reader};
use crate::{ChunkRef, ChunkType, PrimaryHints};
impl<'a> Reader<'a> {
pub fn primary(&self) -> Result<Option<ChunkRef<'a>>, ReadError> {
let ContainerHeader::Chunk(header) = self.header else {
return Ok(None);
};
let Some(chunk_type) = ChunkType::new(header.primary_chunk_type) else {
return Ok(None);
};
Ok(self.chunks().find(|chunk| chunk.chunk_type() == chunk_type))
}
pub const fn primary_hints(&self) -> PrimaryHints {
match self.header {
ContainerHeader::Flat(header) => PrimaryHints::new(
crate::image::SampleLayout::new(header.color_format as u16),
header.width,
header.height,
header.stride,
),
ContainerHeader::Chunk(header) => PrimaryHints::new(
crate::image::SampleLayout::new(header.primary_sample_layout),
header.primary_width,
header.primary_height,
header.primary_stride,
),
}
}
}
#[cfg(test)]
mod tests {
use alloc::vec;
use super::*;
use crate::header::{CHUNK_FILE_HEADER_LEN, VERSION_MINOR, chunk_type};
use crate::{ColorFormat, Layout, crc32, encode_chunks};
fn set_primary(
bytes: &mut [u8],
chunk_type: u16,
sample_layout: u16,
width: u32,
height: u32,
stride: u32,
) {
bytes[20..22].copy_from_slice(&chunk_type.to_le_bytes());
bytes[22..24].copy_from_slice(&sample_layout.to_le_bytes());
bytes[24..28].copy_from_slice(&width.to_le_bytes());
bytes[28..32].copy_from_slice(&height.to_le_bytes());
bytes[32..36].copy_from_slice(&stride.to_le_bytes());
let checksum = crc32(&bytes[..40]);
bytes[40..44].copy_from_slice(&checksum.to_le_bytes());
}
fn flat_a8() -> alloc::vec::Vec<u8> {
let mut bytes = vec![0; crate::FLAT_HEADER_LEN + 1];
bytes[..4].copy_from_slice(b"MIRX");
bytes[4] = crate::VERSION_MAJOR;
bytes[5] = VERSION_MINOR;
bytes[6] = Layout::Flat.to_u8();
bytes[8] = ColorFormat::A8.to_u8();
bytes[12..16].copy_from_slice(&1u32.to_le_bytes());
bytes[16..20].copy_from_slice(&1u32.to_le_bytes());
bytes[20..24].copy_from_slice(&1u32.to_le_bytes());
let checksum = crc32(&bytes[..24]);
bytes[24..28].copy_from_slice(&checksum.to_le_bytes());
bytes
}
#[test]
fn flat_has_image_hints_but_no_chunk_primary() {
let bytes = flat_a8();
let reader = Reader::open(&bytes).unwrap();
assert_eq!(reader.primary(), Ok(None));
assert_eq!(
reader.primary_hints(),
PrimaryHints::new(
crate::image::SampleLayout::from_color_format(ColorFormat::A8),
1,
1,
1
)
);
}
#[test]
fn primary_type_zero_preserves_raw_hints() {
let mut bytes = encode_chunks(&[]);
set_primary(&mut bytes, 0, 0xfedc, 13, 21, 55);
let reader = Reader::open(&bytes).unwrap();
assert_eq!(reader.primary(), Ok(None));
assert_eq!(
reader.primary_hints(),
PrimaryHints::new(crate::image::SampleLayout::new(0xfedc), 13, 21, 55)
);
assert_eq!(reader.primary_hints().known_color_format(), None);
}
#[test]
fn primary_layout_uses_both_header_bytes() {
for layout in [
crate::image::SampleLayout::I420,
crate::image::SampleLayout::NV12,
crate::image::SampleLayout::P010,
crate::image::SampleLayout::new(0xfedc),
] {
let mut bytes = encode_chunks(&[(0xbeef, 0, b"opaque")]);
set_primary(&mut bytes, 0xbeef, layout.raw(), 320, 240, 640);
let reader = Reader::open(&bytes).unwrap();
assert_eq!(reader.primary_hints().sample_layout(), layout);
assert_eq!(reader.primary_hints().known_color_format(), None);
}
}
#[test]
fn resolves_the_first_matching_entry_in_table_order() {
let mut bytes = encode_chunks(&[
(chunk_type::META, 0, b"meta"),
(chunk_type::FONT, 0, b"first"),
(chunk_type::FONT, 0, b"second"),
]);
set_primary(
&mut bytes,
chunk_type::FONT,
crate::image::SampleLayout::NONE.raw(),
0,
0,
0,
);
let reader = Reader::open(&bytes).unwrap();
let primary = reader.primary().unwrap().unwrap();
assert_eq!(primary.index(), 1);
assert_eq!(primary.payload(), b"first");
assert_eq!(primary.chunk_type(), ChunkType::FONT);
}
#[test]
fn resolves_custom_types_and_keeps_legacy_zero_hints() {
let mut bytes = encode_chunks(&[(0xbeef, 0, b"custom")]);
set_primary(&mut bytes, 0xbeef, 0, 0, 0, 0);
let reader = Reader::open(&bytes).unwrap();
let primary = reader.primary().unwrap().unwrap();
assert_eq!(primary.chunk_type().raw(), 0xbeef);
assert_eq!(primary.payload(), b"custom");
assert_eq!(reader.primary_hints(), PrimaryHints::ZERO);
}
#[test]
fn stale_type_remains_queryable() {
let mut bytes = encode_chunks(&[(chunk_type::META, 0, b"meta")]);
set_primary(&mut bytes, chunk_type::VECTOR, 0xa5, 3, 4, 12);
let reader = Reader::open(&bytes).unwrap();
assert_eq!(reader.primary(), Ok(None));
assert_eq!(
reader.primary_hints(),
PrimaryHints::new(crate::image::SampleLayout::new(0xa5), 3, 4, 12)
);
assert_eq!(reader.chunks().next().unwrap().payload(), b"meta");
}
#[test]
fn matching_primary_payload_is_bound_to_the_reader_source() {
let mut bytes = encode_chunks(&[(chunk_type::IMAGE, 0, b"image")]);
set_primary(
&mut bytes,
chunk_type::IMAGE,
crate::image::SampleLayout::RGBA8888.raw(),
2,
3,
8,
);
let reader = Reader::open(&bytes).unwrap();
let primary = reader.primary().unwrap().unwrap();
assert_eq!(
primary.payload().as_ptr(),
bytes[primary.payload_offset() as usize..].as_ptr()
);
assert_eq!(
reader.primary_hints().known_color_format(),
Some(ColorFormat::RGBA8888)
);
assert!(primary.payload_offset() as usize >= CHUNK_FILE_HEADER_LEN);
}
}