tanya/source/tanya/container/queue.d
Eugen Wissner 64f2295d1a Fix #276
Add link to the source file for each module.
2017-08-12 17:01:51 +02:00

291 lines
5.4 KiB
D

/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
/**
* FIFO queue.
*
* Copyright: Eugene Wissner 2016-2017.
* License: $(LINK2 https://www.mozilla.org/en-US/MPL/2.0/,
* Mozilla Public License, v. 2.0).
* Authors: $(LINK2 mailto:info@caraus.de, Eugene Wissner)
* Source: $(LINK2 https://github.com/caraus-ecms/tanya/blob/master/source/tanya/container/queue.d,
* tanya/container/queue.d)
*/
module tanya.container.queue;
import core.exception;
import std.traits;
import std.algorithm.mutation;
import tanya.container.entry;
import tanya.memory;
/**
* FIFO queue.
*
* Params:
* T = Content type.
*/
struct Queue(T)
{
/**
* Removes all elements from the queue.
*/
~this()
{
while (!empty)
{
dequeue();
}
}
/**
* Returns how many elements are in the queue. It iterates through the queue
* to count the elements.
*
* Returns: How many elements are in the queue.
*/
size_t length() const
{
size_t len;
for (const(SEntry!T)* i = first; i !is null; i = i.next)
{
++len;
}
return len;
}
///
unittest
{
Queue!int q;
assert(q.length == 0);
q.enqueue(5);
assert(q.length == 1);
q.enqueue(4);
assert(q.length == 2);
q.enqueue(9);
assert(q.length == 3);
q.dequeue();
assert(q.length == 2);
q.dequeue();
assert(q.length == 1);
q.dequeue();
assert(q.length == 0);
}
private void enqueueEntry(ref SEntry!T* entry)
{
if (empty)
{
first = rear = entry;
}
else
{
rear.next = entry;
rear = rear.next;
}
}
private SEntry!T* allocateEntry()
{
auto temp = cast(SEntry!T*) allocator.allocate(SEntry!T.sizeof);
if (temp is null)
{
onOutOfMemoryError();
}
return temp;
}
/**
* Inserts a new element.
*
* Params:
* x = New element.
*/
void enqueue(ref T x)
{
auto temp = allocateEntry();
*temp = SEntry!T.init;
temp.content = x;
enqueueEntry(temp);
}
/// Ditto.
void enqueue(T x)
{
auto temp = allocateEntry();
moveEmplace(x, (*temp).content);
(*temp).next = null;
enqueueEntry(temp);
}
///
unittest
{
Queue!int q;
assert(q.empty);
q.enqueue(8);
q.enqueue(9);
assert(q.dequeue() == 8);
assert(q.dequeue() == 9);
}
/**
* Returns: $(D_KEYWORD true) if the queue is empty.
*/
@property bool empty() const
{
return first is null;
}
///
unittest
{
Queue!int q;
int value = 7;
assert(q.empty);
q.enqueue(value);
assert(!q.empty);
}
/**
* Move the position to the next element.
*
* Returns: Dequeued element.
*/
T dequeue()
in
{
assert(!empty);
}
body
{
auto n = first.next;
T ret = move(first.content);
allocator.dispose(first);
first = n;
return ret;
}
///
unittest
{
Queue!int q;
q.enqueue(8);
q.enqueue(9);
assert(q.dequeue() == 8);
assert(q.dequeue() == 9);
}
/**
* $(D_KEYWORD foreach) iteration. The elements will be automatically
* dequeued.
*
* Params:
* dg = $(D_KEYWORD foreach) body.
*
* Returns: The value returned from $(D_PARAM dg).
*/
int opApply(scope int delegate(ref size_t i, ref T) @nogc dg)
{
int result;
for (size_t i = 0; !empty; ++i)
{
auto e = dequeue();
if ((result = dg(i, e)) != 0)
{
return result;
}
}
return result;
}
/// Ditto.
int opApply(scope int delegate(ref T) @nogc dg)
{
int result;
while (!empty)
{
auto e = dequeue();
if ((result = dg(e)) != 0)
{
return result;
}
}
return result;
}
///
unittest
{
Queue!int q;
size_t j;
q.enqueue(5);
q.enqueue(4);
q.enqueue(9);
foreach (i, e; q)
{
assert(i != 2 || e == 9);
assert(i != 1 || e == 4);
assert(i != 0 || e == 5);
++j;
}
assert(j == 3);
assert(q.empty);
j = 0;
q.enqueue(5);
q.enqueue(4);
q.enqueue(9);
foreach (e; q)
{
assert(j != 2 || e == 9);
assert(j != 1 || e == 4);
assert(j != 0 || e == 5);
++j;
}
assert(j == 3);
assert(q.empty);
}
private SEntry!T* first;
private SEntry!T* rear;
mixin DefaultAllocator;
}
///
unittest
{
Queue!int q;
q.enqueue(5);
assert(!q.empty);
q.enqueue(4);
q.enqueue(9);
assert(q.dequeue() == 5);
foreach (i, ref e; q)
{
assert(i != 0 || e == 4);
assert(i != 1 || e == 9);
}
assert(q.empty);
}