law fhit

lawful-bytes@0.1.1.0 · proof_fast_find.bend:506

import Base
import lawful-bytes@0.1.1.0/defs.bend as D
import lawful-bytes@0.1.1.0/fast.bend as FA
import lawful-bytes@0.1.1.0/proof_core.bend as C
import lawful-bytes@0.1.1.0/proof_fast_word.bend as FW
import lawful-arrays@0.1.0.0/proof_tree.bend as P

506# The flagged word: the answer is the first c from the start, or to.
507law fhit:
508  for +len: U32
509  for +t: P.Tree<U32>
510  for +d: Nat
511  for +to: U32
512  for +c: U32
513  for +wi: U32
514  for +o: Nat
515  for +v: U32
516  for +h: {D.ok(C.BT(len, t), d) == True{} : Bool}
517  for +ht: {Nat.is_le(U32.to_nat(to), U32.to_nat(len)) == True{} : Bool}
518  for +ho: {Nat.is_lt(o, 4n) == True{} : Bool}
519  for +hs: {Nat.is_le(SS(wi, o), U32.to_nat(to)) == True{} : Bool}
520  for +hk: {Nat.is_lt(U32.to_nat(wi), Nat.pow(2n, d)) == True{} : Bool}
521  for +hv: {FW.P0(v) == Nat.add(o, D.run_len(AW(t, wi, o), c)) : Nat}
522  for +hz: {U32.is_zero(FA.zb(v)) == False{} : Bool}
523  {U32.to_nat(U32.min(((wi << 2n : U32) + FA.bidx(FA.zb(v)) : U32), to)) == D.first(UB(t), SS(wi, o), U32.to_nat(to), c) : Nat}