def png.chunk

gralha-png-decode@0.1.0.1 · png.bend:20

import Base
import gralha-text-scan@0.1.0.1/scan.bend as U
import gralha-bytes@0.1.0.1/bytes.bend as Bin

20def png.chunk(info: PNGInfo, +name: U32, +src: Bin.Bytes, +at: U32, +count: U32) -> PNGInfo:
21  PNGInfo{w, h, depth, kind, interlace, palette, alpha, compressed, valid} = info
22  +pal = palette
23  +trans = alpha
24  +data = compressed
25  PNGInfo{w, h, depth, kind, interlace,
26    U.branch(Bin.Bytes, U32.is_eq(name, 1347179589), _ => Bin.bytes.slice(U32.to_nat(count), src, at, Bin.bytes.empty()), _ => pal),
27    U.branch(Bin.Bytes, U32.is_eq(name, 1951551059), _ => Bin.bytes.slice(U32.to_nat(count), src, at, Bin.bytes.empty()), _ => trans),
28    U.branch(Bin.Bytes, U32.is_eq(name, 1229209940), _ => Bin.bytes.slice(U32.to_nat(count), src, at, data), _ => data),
29    valid && Bool.not(U32.is_eq(name, 1229472850)) && (U32.is_eq(name, 1347179589) || U32.is_eq(name, 1229209940) || U32.is_eq(U32.and(U32.shrn(name, 24n), 32), 32))}
30
31@unsafe