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structure BM =
struct
structure W8A = Word8Array
structure W8 = Word8
structure W = Word
fun create N = W8A.array(W.toIntX(W.>>(W.fromInt(N + 7), 0w3)), 0w0)
fun markAndTest(bitmap,i) =
let val byte = W.toIntX(W.>>(W.fromInt i,0w3))
val mask = W8.<<(0w1, W.andb(W.fromInt i,0w7))
val n = W8A.sub(bitmap, byte)
in W8.andb(n, mask) <> 0w0 orelse
(W8A.update(bitmap, byte, W8.orb(n, mask)); false)
end
fun contains(bitmap,i) =
let val byte = W.toIntX(W.>>(W.fromInt i,0w3))
val mask = W8.<<(0w1, W.andb(W.fromInt i,0w7))
in W8.andb(W8A.sub(bitmap, byte), mask) <> 0w0 end
end
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