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remove queues (#10347)

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This module was deprecated and superseded by deques 2 years ago.
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Miran
2019-01-17 20:37:39 +01:00
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lib/pure/collections/queues.nim
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@@ -1,257 +0,0 @@
#
#
# Nim's Runtime Library
# (c) Copyright 2012 Andreas Rumpf
#
# See the file "copying.txt", included in this
# distribution, for details about the copyright.
#
## Implementation of a `queue`:idx:. The underlying implementation uses a ``seq``.
##
## None of the procs that get an individual value from the queue can be used
## on an empty queue.
## If compiled with `boundChecks` option, those procs will raise an `IndexError`
## on such access. This should not be relied upon, as `-d:release` will
## disable those checks and may return garbage or crash the program.
##
## As such, a check to see if the queue is empty is needed before any
## access, unless your program logic guarantees it indirectly.
##
## .. code-block:: Nim
## proc foo(a, b: Positive) = # assume random positive values for `a` and `b`
## var q = initQueue[int]() # initializes the object
## for i in 1 ..< a: q.add i # populates the queue
##
## if b < q.len: # checking before indexed access
## echo "The element at index position ", b, " is ", q[b]
##
## # The following two lines don't need any checking on access due to the
## # logic of the program, but that would not be the case if `a` could be 0.
## assert q.front == 1
## assert q.back == a
##
## while q.len > 0: # checking if the queue is empty
## echo q.pop()
##
## Note: For inter thread communication use
## a `Channel <channels.html>`_ instead.
import math
{.warning: "`queues` module is deprecated - use `deques` instead".}
type
Queue* {.deprecated.} [T] = object ## A queue.
data: seq[T]
rd, wr, count, mask: int
proc initQueue*[T](initialSize: int = 4): Queue[T] =
## Create a new queue.
## Optionally, the initial capacity can be reserved via `initialSize` as a
## performance optimization. The length of a newly created queue will still
## be 0.
##
## `initialSize` needs to be a power of two. If you need to accept runtime
## values for this you could use the ``nextPowerOfTwo`` proc from the
## `math <math.html>`_ module.
assert isPowerOfTwo(initialSize)
result.mask = initialSize-1
newSeq(result.data, initialSize)
proc len*[T](q: Queue[T]): int {.inline.}=
## Return the number of elements of `q`.
result = q.count
template emptyCheck(q) =
# Bounds check for the regular queue access.
when compileOption("boundChecks"):
if unlikely(q.count < 1):
raise newException(IndexError, "Empty queue.")
template xBoundsCheck(q, i) =
# Bounds check for the array like accesses.
when compileOption("boundChecks"): # d:release should disable this.
if unlikely(i >= q.count): # x < q.low is taken care by the Natural parameter
raise newException(IndexError,
"Out of bounds: " & $i & " > " & $(q.count - 1))
proc front*[T](q: Queue[T]): T {.inline.}=
## Return the oldest element of `q`. Equivalent to `q.pop()` but does not
## remove it from the queue.
emptyCheck(q)
result = q.data[q.rd]
proc back*[T](q: Queue[T]): T {.inline.} =
## Return the newest element of `q` but does not remove it from the queue.
emptyCheck(q)
result = q.data[q.wr - 1 and q.mask]
proc `[]`*[T](q: Queue[T], i: Natural) : T {.inline.} =
## Access the i-th element of `q` by order of insertion.
## q[0] is the oldest (the next one q.pop() will extract),
## q[^1] is the newest (last one added to the queue).
xBoundsCheck(q, i)
return q.data[q.rd + i and q.mask]
proc `[]`*[T](q: var Queue[T], i: Natural): var T {.inline.} =
## Access the i-th element of `q` and returns a mutable
## reference to it.
xBoundsCheck(q, i)
return q.data[q.rd + i and q.mask]
proc `[]=`* [T] (q: var Queue[T], i: Natural, val : T) {.inline.} =
## Change the i-th element of `q`.
xBoundsCheck(q, i)
q.data[q.rd + i and q.mask] = val
iterator items*[T](q: Queue[T]): T =
## Yield every element of `q`.
var i = q.rd
for c in 0 ..< q.count:
yield q.data[i]
i = (i + 1) and q.mask
iterator mitems*[T](q: var Queue[T]): var T =
## Yield every element of `q`.
var i = q.rd
for c in 0 ..< q.count:
yield q.data[i]
i = (i + 1) and q.mask
iterator pairs*[T](q: Queue[T]): tuple[key: int, val: T] =
## Yield every (position, value) of `q`.
var i = q.rd
for c in 0 ..< q.count:
yield (c, q.data[i])
i = (i + 1) and q.mask
proc contains*[T](q: Queue[T], item: T): bool {.inline.} =
## Return true if `item` is in `q` or false if not found. Usually used
## via the ``in`` operator. It is the equivalent of ``q.find(item) >= 0``.
##
## .. code-block:: Nim
## if x in q:
## assert q.contains x
for e in q:
if e == item: return true
return false
proc add*[T](q: var Queue[T], item: T) =
## Add an `item` to the end of the queue `q`.
var cap = q.mask+1
if unlikely(q.count >= cap):
var n = newSeq[T](cap*2)
for i, x in pairs(q): # don't use copyMem because the GC and because it's slower.
shallowCopy(n[i], x)
shallowCopy(q.data, n)
q.mask = cap*2 - 1
q.wr = q.count
q.rd = 0
inc q.count
q.data[q.wr] = item
q.wr = (q.wr + 1) and q.mask
template default[T](t: typedesc[T]): T =
var v: T
v
proc pop*[T](q: var Queue[T]): T {.inline, discardable.} =
## Remove and returns the first (oldest) element of the queue `q`.
emptyCheck(q)
dec q.count
result = q.data[q.rd]
q.data[q.rd] = default(type(result))
q.rd = (q.rd + 1) and q.mask
proc enqueue*[T](q: var Queue[T], item: T) =
## Alias for the ``add`` operation.
q.add(item)
proc dequeue*[T](q: var Queue[T]): T =
## Alias for the ``pop`` operation.
q.pop()
proc `$`*[T](q: Queue[T]): string =
## Turn a queue into its string representation.
result = "["
for x in items(q): # Don't remove the items here for reasons that don't fit in this margin.
if result.len > 1: result.add(", ")
result.add($x)
result.add("]")
when isMainModule:
var q = initQueue[int](1)
q.add(123)
q.add(9)
q.enqueue(4)
var first = q.dequeue()
q.add(56)
q.add(6)
var second = q.pop()
q.add(789)
assert first == 123
assert second == 9
assert($q == "[4, 56, 6, 789]")
assert q[0] == q.front and q.front == 4
q[0] = 42
q[q.len - 1] = 7
assert 6 in q and 789 notin q
assert q.find(6) >= 0
assert q.find(789) < 0
for i in -2 .. 10:
if i in q:
assert q.contains(i) and q.find(i) >= 0
else:
assert(not q.contains(i) and q.find(i) < 0)
when compileOption("boundChecks"):
try:
echo q[99]
assert false
except IndexError:
discard
try:
assert q.len == 4
for i in 0 ..< 5: q.pop()
assert false
except IndexError:
discard
# grabs some types of resize error.
q = initQueue[int]()
for i in 1 .. 4: q.add i
q.pop()
q.pop()
for i in 5 .. 8: q.add i
assert $q == "[3, 4, 5, 6, 7, 8]"
# Similar to proc from the documentation example
proc foo(a, b: Positive) = # assume random positive values for `a` and `b`.
var q = initQueue[int]()
assert q.len == 0
for i in 1 .. a: q.add i
if b < q.len: # checking before indexed access.
assert q[b] == b + 1
# The following two lines don't need any checking on access due to the logic
# of the program, but that would not be the case if `a` could be 0.
assert q.front == 1
assert q.back == a
while q.len > 0: # checking if the queue is empty
assert q.pop() > 0
#foo(0,0)
foo(8,5)
foo(10,9)
foo(1,1)
foo(2,1)
foo(1,5)
foo(3,2)

1
tools/kochdocs.nim
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@@ -177,7 +177,6 @@ lib/pure/collections/lists.nim
lib/pure/collections/sharedlist.nim
lib/pure/collections/sharedtables.nim
lib/pure/collections/intsets.nim
lib/pure/collections/queues.nim
lib/pure/collections/deques.nim
lib/pure/encodings.nim
lib/pure/collections/sequtils.nim