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refactor(ludic.lab): the PNG writer's CRC constants are long literals again

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Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
This commit is contained in:
Orkun ÇAKILKAYA 2026-09-25 08:10:46 +03:00
parent afa4d23a4f
commit ab5584f421
1 changed files with 2 additions and 3 deletions
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5
packages/ludic.lab/png.ludic
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@ -3,11 +3,10 @@
# on every row, in deflate's stored blocks, with its CRCs and its Adler-32.
var lp_table: []long = null
function lp_u32(hi: int, lo: int) -> long { return long(hi) * long(65536) + long(lo) }
function lp_table_init() -> void {
if lp_table != null { return }
lp_table = new []long
let poly = lp_u32(60856, 33568) # 0xEDB88320
let poly: long = 3988292384 # 0xEDB88320: eight hex digits would be a 32-bit pattern
for n in 0 .. 256 {
var c = long(n)
for k in 0 .. 8 {
@ -19,7 +18,7 @@ function lp_table_init() -> void {
# CRC-32 of out[from .. from + n)
function lp_crc(out: []byte, from: int, n: int) -> long {
lp_table_init()
let mask = lp_u32(65535, 65535)
let mask: long = 4294967295
var c = mask
for i in from .. from + n {
let k = int((c ^ long(out[i])) & long(255))