another nice arithmetic operation for the polynomial... | Leonard Ritter

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another nice arithmetic operation for the polynomial rolling hash: computing the hash of replace operations without actually performing them.

do
zero := nullof u128
s := "le quick brown fox jumped over le lazy dogue!"
k := "le quick brown dog jumped over le lazy foxxx!"
u0 := "fox"
u1 := "dog"
v0 := "dogue"
v1 := "foxxx"
Hs := sc_bighashbytes zero ('data s)
Hk := sc_bighashbytes zero ('data k)
Hu0 := sc_bighashbytes zero ('data u0)
Hu1 := sc_bighashbytes zero ('data u1)
Hv0 := sc_bighashbytes zero ('data v0)
Hv1 := sc_bighashbytes zero ('data v1)
Hkk := sc_bighash_replace Hs Hu0 Hu1 ((countof s) - (countof u0) - 15)
Hkk := sc_bighash_replace Hkk Hv0 Hv1 ((countof s) - (countof v0) - 39)
test (Hk == Hkk)

Like 6 Sep 2023 at 15:11 | Open on mastodon.gamedev.place

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