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#
#
# The Nimrod Compiler
# (c) Copyright 2009 Andreas Rumpf
#
# See the file "copying.txt", included in this
# distribution, for details about the copyright.
#
# this unit handles Nimrod sets; it implements symbolic sets
import
ast, astalgo, trees, nversion, msgs, platform, bitsets, types, renderer
proc toBitSet*(s: PNode, b: var TBitSet)
# this function is used for case statement checking:
proc overlap*(a, b: PNode): bool
proc inSet*(s: PNode, elem: PNode): bool
proc someInSet*(s: PNode, a, b: PNode): bool
proc emptyRange*(a, b: PNode): bool
proc SetHasRange*(s: PNode): bool
# returns true if set contains a range (needed by the code generator)
# these are used for constant folding:
proc unionSets*(a, b: PNode): PNode
proc diffSets*(a, b: PNode): PNode
proc intersectSets*(a, b: PNode): PNode
proc symdiffSets*(a, b: PNode): PNode
proc containsSets*(a, b: PNode): bool
proc equalSets*(a, b: PNode): bool
proc cardSet*(s: PNode): BiggestInt
# implementation
proc inSet(s: PNode, elem: PNode): bool =
if s.kind != nkCurly: InternalError(s.info, "inSet")
for i in countup(0, sonsLen(s) - 1):
if s.sons[i].kind == nkRange:
if leValue(s.sons[i].sons[0], elem) and
leValue(elem, s.sons[i].sons[1]):
return true
else:
if sameValue(s.sons[i], elem):
return true
result = false
proc overlap(a, b: PNode): bool =
if a.kind == nkRange:
if b.kind == nkRange:
result = leValue(a.sons[0], b.sons[1]) and
leValue(b.sons[1], a.sons[1]) or
leValue(a.sons[0], b.sons[0]) and leValue(b.sons[0], a.sons[1])
else:
result = leValue(a.sons[0], b) and leValue(b, a.sons[1])
else:
if b.kind == nkRange:
result = leValue(b.sons[0], a) and leValue(a, b.sons[1])
else:
result = sameValue(a, b)
proc SomeInSet(s: PNode, a, b: PNode): bool =
# checks if some element of a..b is in the set s
if s.kind != nkCurly: InternalError(s.info, "SomeInSet")
for i in countup(0, sonsLen(s) - 1):
if s.sons[i].kind == nkRange:
if leValue(s.sons[i].sons[0], b) and leValue(b, s.sons[i].sons[1]) or
leValue(s.sons[i].sons[0], a) and leValue(a, s.sons[i].sons[1]):
return true
else:
# a <= elem <= b
if leValue(a, s.sons[i]) and leValue(s.sons[i], b):
return true
result = false
proc toBitSet(s: PNode, b: var TBitSet) =
var first, j: BiggestInt
first = firstOrd(s.typ.sons[0])
bitSetInit(b, int(getSize(s.typ)))
for i in countup(0, sonsLen(s) - 1):
if s.sons[i].kind == nkRange:
j = getOrdValue(s.sons[i].sons[0])
while j <= getOrdValue(s.sons[i].sons[1]):
BitSetIncl(b, j - first)
inc(j)
else:
BitSetIncl(b, getOrdValue(s.sons[i]) - first)
proc ToTreeSet(s: TBitSet, settype: PType, info: TLineInfo): PNode =
var
a, b, e, first: BiggestInt # a, b are interval borders
elemType: PType
n: PNode
elemType = settype.sons[0]
first = firstOrd(elemType)
result = newNodeI(nkCurly, info)
result.typ = settype
result.info = info
e = 0
while e < high(s) * elemSize:
if bitSetIn(s, e):
a = e
b = e
while true:
Inc(b)
if (b > high(s) * elemSize) or not bitSetIn(s, b): break
Dec(b)
if a == b:
addSon(result, newIntTypeNode(nkIntLit, a + first, elemType))
else:
n = newNodeI(nkRange, info)
n.typ = elemType
addSon(n, newIntTypeNode(nkIntLit, a + first, elemType))
addSon(n, newIntTypeNode(nkIntLit, b + first, elemType))
addSon(result, n)
e = b
Inc(e)
type
TSetOP = enum
soUnion, soDiff, soSymDiff, soIntersect
proc nodeSetOp(a, b: PNode, op: TSetOp): PNode =
var x, y: TBitSet
toBitSet(a, x)
toBitSet(b, y)
case op
of soUnion: BitSetUnion(x, y)
of soDiff: BitSetDiff(x, y)
of soSymDiff: BitSetSymDiff(x, y)
of soIntersect: BitSetIntersect(x, y)
result = toTreeSet(x, a.typ, a.info)
proc unionSets(a, b: PNode): PNode =
result = nodeSetOp(a, b, soUnion)
proc diffSets(a, b: PNode): PNode =
result = nodeSetOp(a, b, soDiff)
proc intersectSets(a, b: PNode): PNode =
result = nodeSetOp(a, b, soIntersect)
proc symdiffSets(a, b: PNode): PNode =
result = nodeSetOp(a, b, soSymDiff)
proc containsSets(a, b: PNode): bool =
var x, y: TBitSet
toBitSet(a, x)
toBitSet(b, y)
result = bitSetContains(x, y)
proc equalSets(a, b: PNode): bool =
var x, y: TBitSet
toBitSet(a, x)
toBitSet(b, y)
result = bitSetEquals(x, y)
proc cardSet(s: PNode): BiggestInt =
# here we can do better than converting it into a compact set
# we just count the elements directly
result = 0
for i in countup(0, sonsLen(s) - 1):
if s.sons[i].kind == nkRange:
result = result + getOrdValue(s.sons[i].sons[1]) -
getOrdValue(s.sons[i].sons[0]) + 1
else:
Inc(result)
proc SetHasRange(s: PNode): bool =
if s.kind != nkCurly: InternalError(s.info, "SetHasRange")
for i in countup(0, sonsLen(s) - 1):
if s.sons[i].kind == nkRange:
return true
result = false
proc emptyRange(a, b: PNode): bool =
result = not leValue(a, b) # a > b iff not (a <= b)
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