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remove a condition that table size must be passed as power of 2 (#14926)

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* remove a condition that table size must be passed as power of 2
* remove power-of-2 condition from sets and sharedtables
* remove power-of-2 condition from deques
* use 'correctSize' for both branches
* prettify changelog.md and fix typos
* add a changelog entry
* fix double-call of 'right-size'
* fix the same thing in sets.nim
* introduce a new internal proc `slotsNeeded`

Deprecate the public proc `rightSize`, which is not needed anymore.
Now it is an identity function, allowing the old code to work
correctly and without extra allocations.
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Miran 2020-07-08 15:01:47 +02:00 • committed by GitHub
commit 3de5296337
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10 changed files with 83 additions and 120 deletions
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30
lib/pure/collections/sets.nim
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@ -94,11 +94,6 @@ include setimpl
proc init*[A](s: var HashSet[A], initialSize = defaultInitialSize) =
## Initializes a hash set.
##
## The `initialSize` parameter needs to be a power of two (default: 64).
## If you need to accept runtime values for this, you can use
## `math.nextPowerOfTwo proc <math.html#nextPowerOfTwo,int>`_ or
## `rightSize proc <#rightSize,Natural>`_ from this module.
##
## Starting from Nim v0.20, sets are initialized by default and it is
## not necessary to call this function explicitly.
##
@ -222,7 +217,7 @@ proc toHashSet*[A](keys: openArray[A]): HashSet[A] =
assert len(b) == 5
## b == {'a', 'b', 'c', 'd', 'r'}
result = initHashSet[A](rightSize(keys.len))
result = initHashSet[A](keys.len)
for key in items(keys): result.incl(key)
iterator items*[A](s: HashSet[A]): A =
@ -628,11 +623,6 @@ template forAllOrderedPairs(yieldStmt: untyped) {.dirty.} =
proc init*[A](s: var OrderedSet[A], initialSize = defaultInitialSize) =
## Initializes an ordered hash set.
##
## The `initialSize` parameter needs to be a power of two (default: 64).
## If you need to accept runtime values for this, you can use
## `math.nextPowerOfTwo proc <math.html#nextPowerOfTwo,int>`_ or
## `rightSize proc <#rightSize,Natural>`_ from this module.
##
## Starting from Nim v0.20, sets are initialized by default and it is
## not necessary to call this function explicitly.
##
@ -685,7 +675,7 @@ proc toOrderedSet*[A](keys: openArray[A]): OrderedSet[A] =
assert len(b) == 5
## b == {'a', 'b', 'r', 'c', 'd'} # different than in HashSet
result = initOrderedSet[A](rightSize(keys.len))
result = initOrderedSet[A](keys.len)
for key in items(keys): result.incl(key)
proc contains*[A](s: OrderedSet[A], key: A): bool =
@ -980,7 +970,7 @@ when isMainModule and not defined(release):
block toSeqAndString:
var a = toHashSet([2, 7, 5])
var b = initHashSet[int](rightSize(a.len))
var b = initHashSet[int](a.len)
for x in [2, 7, 5]: b.incl(x)
assert($a == $b)
#echo a
@ -1098,20 +1088,6 @@ when isMainModule and not defined(release):
b.incl(2)
assert b.len == 1
block:
type FakeTable = object
dataLen: int
counter: int
countDeleted: int
var t: FakeTable
for i in 0 .. 32:
var s = rightSize(i)
t.dataLen = s
t.counter = i
doAssert s > i and not mustRehash(t),
"performance issue: rightSize() will not elide enlarge() at: " & $i
block missingOrExcl:
var s = toOrderedSet([2, 3, 6, 7])
assert s.missingOrExcl(4) == true