diff options
Diffstat (limited to 'lib/pure/collections/intsets.nim')
-rw-r--r-- | lib/pure/collections/intsets.nim | 66 |
1 files changed, 33 insertions, 33 deletions
diff --git a/lib/pure/collections/intsets.nim b/lib/pure/collections/intsets.nim index 7520e6e46..ae26c5af6 100644 --- a/lib/pure/collections/intsets.nim +++ b/lib/pure/collections/intsets.nim @@ -14,12 +14,12 @@ ## copy; use ``assign`` to get a deep copy. import - os, hashes, math + hashes, math type BitScalar = int -const +const InitIntSetSize = 8 # must be a power of two! TrunkShift = 9 BitsPerTrunk = 1 shl TrunkShift # needs to be a power of 2 and @@ -31,11 +31,11 @@ const type PTrunk = ref TTrunk - TTrunk {.final.} = object + TTrunk {.final.} = object next: PTrunk # all nodes are connected with this pointer key: int # start address at bit 0 bits: array[0..IntsPerTrunk - 1, BitScalar] # a bit vector - + TTrunkSeq = seq[PTrunk] IntSet* = object ## an efficient set of 'int' implemented as a sparse bit set counter, max: int @@ -44,42 +44,42 @@ type {.deprecated: [TIntSet: IntSet].} -proc mustRehash(length, counter: int): bool {.inline.} = +proc mustRehash(length, counter: int): bool {.inline.} = assert(length > counter) result = (length * 2 < counter * 3) or (length - counter < 4) -proc nextTry(h, maxHash: THash): THash {.inline.} = - result = ((5 * h) + 1) and maxHash +proc nextTry(h, maxHash: THash): THash {.inline.} = + result = ((5 * h) + 1) and maxHash -proc intSetGet(t: IntSet, key: int): PTrunk = +proc intSetGet(t: IntSet, key: int): PTrunk = var h = key and t.max - while t.data[h] != nil: - if t.data[h].key == key: + while t.data[h] != nil: + if t.data[h].key == key: return t.data[h] h = nextTry(h, t.max) result = nil -proc intSetRawInsert(t: IntSet, data: var TTrunkSeq, desc: PTrunk) = +proc intSetRawInsert(t: IntSet, data: var TTrunkSeq, desc: PTrunk) = var h = desc.key and t.max - while data[h] != nil: + while data[h] != nil: assert(data[h] != desc) h = nextTry(h, t.max) assert(data[h] == nil) data[h] = desc -proc intSetEnlarge(t: var IntSet) = +proc intSetEnlarge(t: var IntSet) = var n: TTrunkSeq var oldMax = t.max t.max = ((t.max + 1) * 2) - 1 newSeq(n, t.max + 1) - for i in countup(0, oldMax): + for i in countup(0, oldMax): if t.data[i] != nil: intSetRawInsert(t, n, t.data[i]) swap(t.data, n) -proc intSetPut(t: var IntSet, key: int): PTrunk = +proc intSetPut(t: var IntSet, key: int): PTrunk = var h = key and t.max - while t.data[h] != nil: - if t.data[h].key == key: + while t.data[h] != nil: + if t.data[h].key == key: return t.data[h] h = nextTry(h, t.max) if mustRehash(t.max + 1, t.counter): intSetEnlarge(t) @@ -94,43 +94,43 @@ proc intSetPut(t: var IntSet, key: int): PTrunk = t.data[h] = result proc contains*(s: IntSet, key: int): bool = - ## returns true iff `key` is in `s`. + ## returns true iff `key` is in `s`. var t = intSetGet(s, `shr`(key, TrunkShift)) - if t != nil: + if t != nil: var u = key and TrunkMask result = (t.bits[`shr`(u, IntShift)] and `shl`(1, u and IntMask)) != 0 - else: + else: result = false - -proc incl*(s: var IntSet, key: int) = + +proc incl*(s: var IntSet, key: int) = ## includes an element `key` in `s`. var t = intSetPut(s, `shr`(key, TrunkShift)) var u = key and TrunkMask t.bits[`shr`(u, IntShift)] = t.bits[`shr`(u, IntShift)] or `shl`(1, u and IntMask) -proc excl*(s: var IntSet, key: int) = +proc excl*(s: var IntSet, key: int) = ## excludes `key` from the set `s`. var t = intSetGet(s, `shr`(key, TrunkShift)) - if t != nil: + if t != nil: var u = key and TrunkMask t.bits[`shr`(u, IntShift)] = t.bits[`shr`(u, IntShift)] and not `shl`(1, u and IntMask) -proc containsOrIncl*(s: var IntSet, key: int): bool = +proc containsOrIncl*(s: var IntSet, key: int): bool = ## returns true if `s` contains `key`, otherwise `key` is included in `s` ## and false is returned. var t = intSetGet(s, `shr`(key, TrunkShift)) - if t != nil: + if t != nil: var u = key and TrunkMask result = (t.bits[`shr`(u, IntShift)] and `shl`(1, u and IntMask)) != 0 - if not result: + if not result: t.bits[`shr`(u, IntShift)] = t.bits[`shr`(u, IntShift)] or `shl`(1, u and IntMask) - else: + else: incl(s, key) result = false - + proc initIntSet*: IntSet = ## creates a new int set that is empty. newSeq(result.data, InitIntSetSize) @@ -140,14 +140,14 @@ proc initIntSet*: IntSet = proc assign*(dest: var IntSet, src: IntSet) = ## copies `src` to `dest`. `dest` does not need to be initialized by - ## `initIntSet`. + ## `initIntSet`. dest.counter = src.counter dest.max = src.max newSeq(dest.data, src.data.len) - + var it = src.head while it != nil: - + var h = it.key and dest.max while dest.data[h] != nil: h = nextTry(h, dest.max) assert(dest.data[h] == nil) @@ -168,7 +168,7 @@ iterator items*(s: IntSet): int {.inline.} = while r != nil: var i = 0 while i <= high(r.bits): - var w = r.bits[i] + var w = r.bits[i] # taking a copy of r.bits[i] here is correct, because # modifying operations are not allowed during traversation var j = 0 |