exr 1.74.1

Read and write OpenEXR files without any unsafe code
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46

// see https://github.com/openexr/openexr/blob/master/OpenEXR/IlmImf/ImfCompressor.cpp

use super::{optimize_bytes::*, *};
use crate::error::Result;

// scanline decompression routine, see https://github.com/openexr/openexr/blob/master/OpenEXR/IlmImf/ImfScanLineInputFile.cpp
// 1. Uncompress the data, if necessary (If the line is uncompressed, it's in
//    XDR format, regardless of the compressor's output format.)
// 3. Convert one scan line's worth of pixel data back from the
//    machine-independent representation
// 4. Fill the frame buffer with pixel data, respective to sampling and whatnot

pub fn decompress_bytes(
    channels: &ChannelList,
    data_le: ByteVec,
    rectangle: IntegerBounds,
    expected_byte_size: usize,
    _pedantic: bool,
) -> Result<ByteVec> {
    let options = zune_inflate::DeflateOptions::default()
        .set_limit(expected_byte_size)
        .set_size_hint(expected_byte_size);
    let mut decoder = zune_inflate::DeflateDecoder::new_with_options(&data_le, options);
    let mut decompressed_le =
        decoder.decode_zlib().map_err(|_| Error::invalid("zlib-compressed data malformed"))?;

    differences_to_samples(&mut decompressed_le);
    interleave_byte_blocks(&mut decompressed_le);

    super::convert_little_endian_to_current(decompressed_le, channels, rectangle)
    // TODO no alloc
}

pub fn compress_bytes(
    channels: &ChannelList,
    uncompressed_ne: ByteVec,
    rectangle: IntegerBounds,
) -> Result<ByteVec> {
    // see https://github.com/AcademySoftwareFoundation/openexr/blob/3bd93f85bcb74c77255f28cdbb913fdbfbb39dfe/OpenEXR/IlmImf/ImfTiledOutputFile.cpp#L750-L842
    let mut packed_le = convert_current_to_little_endian(uncompressed_ne, channels, rectangle)?;

    separate_bytes_fragments(&mut packed_le);
    samples_to_differences(&mut packed_le);

    Ok(miniz_oxide::deflate::compress_to_vec_zlib(packed_le.as_slice(), 4))
}