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72 lines
2.2 KiB
Nim
Executable File
72 lines
2.2 KiB
Nim
Executable File
#
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#
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# The Nimrod Compiler
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# (c) Copyright 2012 Andreas Rumpf
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#
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# See the file "copying.txt", included in this
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# distribution, for details about the copyright.
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#
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# this unit handles Nimrod sets; it implements bit sets
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# the code here should be reused in the Nimrod standard library
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type
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TBitSet* = seq[int8] # we use byte here to avoid issues with
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# cross-compiling; uint would be more efficient
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# however
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const
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ElemSize* = sizeof(int8) * 8
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proc BitSetInit*(b: var TBitSet, length: int)
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proc BitSetUnion*(x: var TBitSet, y: TBitSet)
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proc BitSetDiff*(x: var TBitSet, y: TBitSet)
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proc BitSetSymDiff*(x: var TBitSet, y: TBitSet)
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proc BitSetIntersect*(x: var TBitSet, y: TBitSet)
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proc BitSetIncl*(x: var TBitSet, elem: BiggestInt)
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proc BitSetExcl*(x: var TBitSet, elem: BiggestInt)
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proc BitSetIn*(x: TBitSet, e: BiggestInt): bool
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proc BitSetEquals*(x, y: TBitSet): bool
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proc BitSetContains*(x, y: TBitSet): bool
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# implementation
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proc BitSetIn(x: TBitSet, e: BiggestInt): bool =
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result = (x[int(e div ElemSize)] and toU8(int(1 shl (e mod ElemSize)))) !=
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toU8(0)
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proc BitSetIncl(x: var TBitSet, elem: BiggestInt) =
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assert(elem >= 0)
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x[int(elem div ElemSize)] = x[int(elem div ElemSize)] or
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toU8(int(1 shl (elem mod ElemSize)))
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proc BitSetExcl(x: var TBitSet, elem: BiggestInt) =
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x[int(elem div ElemSize)] = x[int(elem div ElemSize)] and
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not toU8(int(1 shl (elem mod ElemSize)))
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proc BitSetInit(b: var TBitSet, length: int) =
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newSeq(b, length)
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proc BitSetUnion(x: var TBitSet, y: TBitSet) =
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for i in countup(0, high(x)): x[i] = x[i] or y[i]
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proc BitSetDiff(x: var TBitSet, y: TBitSet) =
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for i in countup(0, high(x)): x[i] = x[i] and not y[i]
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proc BitSetSymDiff(x: var TBitSet, y: TBitSet) =
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for i in countup(0, high(x)): x[i] = x[i] xor y[i]
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proc BitSetIntersect(x: var TBitSet, y: TBitSet) =
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for i in countup(0, high(x)): x[i] = x[i] and y[i]
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proc BitSetEquals(x, y: TBitSet): bool =
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for i in countup(0, high(x)):
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if x[i] != y[i]:
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return false
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result = true
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proc BitSetContains(x, y: TBitSet): bool =
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for i in countup(0, high(x)):
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if (x[i] and not y[i]) != int8(0):
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return false
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result = true
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