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<?php
/*
* This file is part of Fusonic-linq.
*
* (c) Fusonic GmbH
*
* For the full copyright and license information, please view the LICENSE
* file that was distributed with this source code.
*/
namespace Fusonic\Linq;
use Countable;
use Fusonic\Linq\Iterator\ExceptIterator;
use Fusonic\Linq\Iterator\DistinctIterator;
use Fusonic\Linq\Iterator\GroupIterator;
use Fusonic\Linq\Iterator\IntersectIterator;
use Fusonic\Linq\Iterator\OfTypeIterator;
use Fusonic\Linq\Iterator\OrderIterator;
use Fusonic\Linq\Iterator\SelectIterator;
use Fusonic\Linq\Iterator\SelectManyIterator;
use Fusonic\Linq\Iterator\WhereIterator;
use Fusonic\Linq\Helper\LinqHelper;
use IteratorAggregate;
use Traversable;
use UnexpectedValueException;
use InvalidArgumentException;
use OutOfRangeException;
/**
* Linq is a simple, powerful and consistent library for querying, projecting and aggregating data in php.
*
* @author David Roth <david.roth@fusonic.net>.
*/
class Linq implements IteratorAggregate, Countable
{
private $iterator;
/**
* Creates a new Linq object using the provided dataSource.
*
* @param array|\Iterator|IteratorAggregate $dataSource A Traversable sequence as data source.
*/
public function __construct($dataSource)
{
LinqHelper::assertArgumentIsIterable($dataSource, "dataSource");
$dataSource = LinqHelper::getIteratorOrThrow($dataSource);
$this->iterator = $dataSource;
}
/**
* Creates a new Linq object using the provided dataDataSource.
* This is the recommended way for getting a new Linq instance.
*
* @param array|\Iterator|IteratorAggregate $dataSource A Traversable sequence as data source.
* @return Linq
*/
public static function from($dataSource)
{
return new Linq($dataSource);
}
/**
* Generates a sequence of integral numbers within a specified range.
*
* @param $start The value of the first integer in the sequence.
* @param $count The number of sequential integers to generate.
* @return Linq An sequence that contains a range of sequential int numbers.
* @throws \OutOfRangeException
*/
public static function range($start, $count)
{
if ($count < 0) {
throw new OutOfRangeException('$count must be not be negative.');
}
return new Linq(range($start, $start + $count - 1));
}
/**
* Filters the Linq object according to func return result.
*
* @param callback $func A func that returns boolean
* @return Linq Filtered results according to $func
*/
public function where($func)
{
return new Linq(new WhereIterator($this->iterator, $func));
}
/**
* Filters the Linq object according to type.
*
* @param string $type
*
* @return Linq Filtered results according to $func
*/
public function ofType($type)
{
return new Linq(new OfTypeIterator($this->iterator, $type));
}
/**
* Bypasses a specified number of elements and then returns the remaining elements.
*
* @param int $count The number of elements to skip before returning the remaining elements.
* @return Linq A Linq object that contains the elements that occur after the specified index.
*/
public function skip($count)
{
// If its an array iterator we must check the arrays bounds are greater than the skip count.
// This is because the LimitIterator will use the seek() method which will throw an exception if $count > array.bounds.
$innerIterator = $this->iterator;
if ($innerIterator instanceof \ArrayIterator) {
if ($count >= $innerIterator->count()) {
return new Linq(array());
}
}
return new Linq(new \LimitIterator($innerIterator, $count, -1));
}
/**
* Returns a specified number of contiguous elements from the start of a sequence
*
* @param int $count The number of elements to return.
* @return Linq A Linq object that contains the specified number of elements from the start.
*/
public function take($count)
{
if ($count == 0) {
return new Linq(array());
}
return new Linq(new \LimitIterator($this->iterator, 0, $count));
}
/**
* Applies an accumulator function over a sequence.
* The aggregate method makes it simple to perform a calculation over a sequence of values.
* This method works by calling $func one time for each element.
* The first element of source is used as the initial aggregate value if $seed parameter is not specified.
* If $seed is specified, this value will be used as the first value.
*
* @param callback $func An accumulator function to be invoked on each element.
* @param mixed $seed
* @throws \RuntimeException if the input sequence contains no elements.
* @return mixed Returns the final result of $func.
*/
public function aggregate($func, $seed = null)
{
$result = null;
$first = true;
if ($seed !== null) {
$result = $seed;
$first = false;
}
foreach ($this->iterator as $current) {
if (!$first) {
$result = $func($result, $current);
} else {
$result = $current;
$first = false;
}
}
if ($first) {
throw new \RuntimeException("The input sequence contains no elements.");
}
return $result;
}
/**
* Splits the sequence in chunks according to $chunksize.
*
* @param $chunksize Specifies how many elements are grouped together per chunk.
* @throws \InvalidArgumentException
* @return Linq
*/
public function chunk($chunksize)
{
if ($chunksize < 1) {
throw new \InvalidArgumentException("chunksize", $chunksize);
}
$i = -1;
return $this->select(
function ($x) use (&$i) {
$i++;
return array("index" => $i, "value" => $x);
}
)
->groupBy(
function ($pair) use ($chunksize) {
return $pair["index"] / $chunksize;
}
)
->select(
function (GroupedLinq $group) {
return $group->select(
function ($v) {
return $v["value"];
}
);
}
);
}
/**
* Determines whether all elements satisfy a condition.
*
* @param callback $func A function to test each element for a condition.
* @return bool True if every element passes the test in the specified func, or if the sequence is empty; otherwise, false.
*/
public function all($func)
{
foreach ($this->iterator as $current) {
$match = LinqHelper::getBoolOrThrowException($func($current));
if (!$match) {
return false;
}
}
return true;
}
/**
* Determines whether any element exists or satisfies a condition by invoking $func.
*
* @param callback $func A function to test each element for a condition or NULL to determine if any element exists.
* @return bool True if no $func given and the source sequence contains any elements or True if any elements passed the test in the specified func; otherwise, false.
*/
public function any($func = null)
{
foreach ($this->iterator as $current) {
if ($func === null) {
return true;
}
$match = LinqHelper::getBoolOrThrowException($func($current));
if ($match) {
return true;
}
}
return false;
}
/**
* Counts the elements of this Linq sequence.
* @return int
*/
public function count()
{
if ($this->iterator instanceof Countable) {
return $this->iterator->count();
}
return iterator_count($this->iterator);
}
/**
* Computes the average of all numeric values. Uses $func to obtain the value on each element.
*
* @param callback $func A func that returns any numeric type (int, float etc.)
* @throws \UnexpectedValueException if an item of the sequence is not a numeric value.
* @return double Average of items
*/
public function average($func = null)
{
$resultTotal = 0;
$itemCount = 0;
$source = $this->getSelectIteratorOrInnerIterator($func);
foreach ($source as $item) {
if (!is_numeric($item)) {
throw new UnexpectedValueException("Cannot calculate an average on a none numeric value");
}
$resultTotal += $item;
$itemCount++;
}
return $itemCount == 0 ? 0 : ($resultTotal / $itemCount);
}
/**
* Sorts the elements in ascending order according to a key provided by $func.
*
* @param callback $func A function to extract a key from an element.
* @return Linq A new Linq instance whose elements are sorted ascending according to a key.
*/
public function orderBy($func)
{
return $this->order($func, LinqHelper::LINQ_ORDER_ASC);
}
/**
* Sorts the elements in descending order according to a key provided by $func.
*
* @param callback $func A function to extract a key from an element.
* @return Linq A new Linq instance whose elements are sorted descending according to a key.
*/
public function orderByDescending($func)
{
return $this->order($func, LinqHelper::LINQ_ORDER_DESC);
}
private function order($func, $direction = LinqHelper::LINQ_ORDER_ASC)
{
return new Linq(new OrderIterator($this->iterator, $func, $direction));
}
/**
* Gets the sum of all items or by invoking a transform function on each item to get a numeric value.
*
* @param callback $func A func that returns any numeric type (int, float etc.) from the given element, or NULL to use the element itself.
* @throws \UnexpectedValueException if any element is not a numeric value.
* @return double The sum of all items.
*/
public function sum($func = null)
{
$sum = 0;
$iterator = $this->getSelectIteratorOrInnerIterator($func);
foreach ($iterator as $value) {
if (!is_numeric($value)) {
throw new UnexpectedValueException("sum() only works on numeric values.");
}
$sum += $value;
}
return $sum;
}
/**
* Gets the minimum item value of all items or by invoking a transform function on each item to get a numeric value.
*
* @param callback $func A func that returns any numeric type (int, float etc.) from the given element, or NULL to use the element itself.
* @throws \RuntimeException if the sequence contains no elements
* @throws \UnexpectedValueException
* @return double Minimum item value
*/
public function min($func = null)
{
$min = null;
$iterator = $this->getSelectIteratorOrInnerIterator($func);
foreach ($iterator as $value) {
if (!is_numeric($value) && !is_string($value) && !($value instanceof \DateTime)) {
throw new UnexpectedValueException("min() only works on numeric values, strings and DateTime objects.");
}
if (is_null($min)) {
$min = $value;
} elseif ($min > $value) {
$min = $value;
}
}
if ($min === null) {
throw new \RuntimeException("Cannot calculate min() as the Linq sequence contains no elements.");
}
return $min;
}
/**
* Returns the maximum item value according to $func
*
* @param callback $func A func that returns any numeric type (int, float etc.)
* @throws \RuntimeException if the sequence contains no elements
* @throws \UnexpectedValueException if any element is not a numeric value or a string.
* @return double Maximum item value
*/
public function max($func = null)
{
$max = null;
$iterator = $this->getSelectIteratorOrInnerIterator($func);
foreach ($iterator as $value) {
if (!is_numeric($value) && !is_string($value) && !($value instanceof \DateTime)) {
throw new UnexpectedValueException("max() only works on numeric values, strings and DateTime objects.");
}
if (is_null($max)) {
$max = $value;
} elseif ($max < $value) {
$max = $value;
}
}
if ($max === null) {
throw new \RuntimeException("Cannot calculate max() as the Linq sequence contains no elements.");
}
return $max;
}
/**
* Projects each element into a new form by invoking the selector function.
*
* @param callback $func A transform function to apply to each element.
* @return Linq A new Linq object whose elements are the result of invoking the transform function on each element of the original Linq object.
*/
public function select($func)
{
return new Linq(new SelectIterator($this->iterator, $func));
}
/**
* Projects each element of a sequence to a new Linq and flattens the resulting sequences into one sequence.
*
* @param callback $func A func that returns a sequence (array, Linq, Iterator).
* @throws \UnexpectedValueException if an element is not a traversable sequence.
* @return Linq A new Linq object whose elements are the result of invoking the one-to-many transform function on each element of the input sequence.
*/
public function selectMany($func)
{
return new Linq(new SelectManyIterator(new SelectIterator($this->iterator, $func)));
}
/**
* Performs the specified action on each element of the Linq sequence and returns the Linq sequence.
* @param callback $func A func that will be evaluated for each item in the linq sequence.
* @return Linq The original Linq sequence that was used to perform the foreach.
*/
public function each($func)
{
foreach ($this->iterator as $item) {
$func($item);
}
return $this;
}
/**
* Determines whether a sequence contains a specified element.
* This function will use php strict comparison (===). If you need custom comparison use the Linq::any($func) method.
*
* @param mixed $value The value to locate in the sequence.
* @return bool True if $value is found within the sequence; otherwise false.
*/
public function contains($value)
{
return $this->any(
function ($x) use ($value) {
return $x === $value;
}
);
}
/**
* Concatenates this Linq object with the given sequence.
*
* @param array|\Iterator $second A sequence which will be concatenated with this Linq object.
* @throws InvalidArgumentException if the given sequence is not traversable.
* @return Linq A new Linq object that contains the concatenated elements of the input sequence and the original Linq sequence.
*/
public function concat($second)
{
LinqHelper::assertArgumentIsIterable($second, "second");
$allItems = new \ArrayIterator(array($this->iterator, $second));
return new Linq(new SelectManyIterator($allItems));
}
/**
* Returns distinct item values of this
*
* @param callback $func
* @return Linq Distinct item values of this
*/
public function distinct($func = null)
{
return new Linq(new DistinctIterator($this->getSelectIteratorOrInnerIterator($func)));
}
/**
* Intersects the Linq sequence with second Iterable sequence.
*
* @param \Iterator|array An iterator to intersect with:
* @return Linq intersected items
*/
public function intersect($second)
{
LinqHelper::assertArgumentIsIterable($second, "second");
return new Linq(new IntersectIterator($this->iterator, LinqHelper::getIteratorOrThrow($second)));
}
/**
* Returns all elements except the ones of the given sequence.
*
* @param array|\Iterator $second
* @return Linq Returns all items of this not occuring in $second
*/
public function except($second)
{
LinqHelper::assertArgumentIsIterable($second, "second");
return new Linq(new ExceptIterator($this->iterator, LinqHelper::getIteratorOrThrow($second)));
}
/**
* Returns the element at a specified index.
* This method throws an exception if index is out of range.
* To instead return NULL when the specified index is out of range, use the elementAtOrNull method.
*
* @throws \OutOfRangeException if index is less than 0 or greater than or equal to the number of elements in the sequence.
* @param int $index
* @return mixed Item at $index
*/
public function elementAt($index)
{
return $this->getValueAt($index, true);
}
/**
* Returns the element at a specified index or NULL if the index is out of range.
*
* @param $index
* @return mixed Item at $index
*/
public function elementAtOrNull($index)
{
return $this->getValueAt($index, false);
}
private function getValueAt($index, $throwEx)
{
$i = 0;
foreach ($this->iterator as $value) {
if ($i == $index) {
return $value;
}
$i++;
}
if ($throwEx) {
throw new OutOfRangeException("Index is less than 0 or greater than or equal to the number of elements in the sequence.");
}
return null;
}
/**
* Groups the object according to the $func generated key
*
* @param callback $keySelector a func that returns an item as key, item can be any type.
* @return GroupedLinq
*/
public function groupBy($keySelector)
{
return new Linq(new GroupIterator($this->iterator, $keySelector));
}
/**
* Returns the last element that satisfies a specified condition.
* @throws \RuntimeException if no element satisfies the condition in predicate or the source sequence is empty.
*
* @param callback $func a func that returns boolean.
* @return Object Last item in this
*/
public function last($func = null)
{
return $this->getLast($func, true);
}
/**
* Returns the last element that satisfies a condition or NULL if no such element is found.
*
* @param callback $func a func that returns boolean.
* @return mixed
*/
public function lastOrNull($func = null)
{
return $this->getLast($func, false);
}
/**
* Returns the first element that satisfies a specified condition
* @throws \RuntimeException if no element satisfies the condition in predicate -or- the source sequence is empty / does not match any elements.
*
* @param callback $func a func that returns boolean.
* @return mixed
*/
public function first($func = null)
{
return $this->getFirst($func, true);
}
/**
* Returns the first element, or NULL if the sequence contains no elements.
*
* @param callback $func a func that returns boolean.
* @return mixed
*/
public function firstOrNull($func = null)
{
return $this->getFirst($func, false);
}
/**
* Returns the only element that satisfies a specified condition.
*
* @throws \RuntimeException if no element exists or if more than one element exists.
* @param callback $func a func that returns boolean.
* @return mixed
*/
public function single($func = null)
{
return $this->getSingle($func, true);
}
/**
* Returns the only element that satisfies a specified condition or NULL if no such element exists.
*
* @throws \RuntimeException if more than one element satisfies the condition.
* @param callback $func a func that returns boolean.
* @return mixed
*/
public function singleOrNull($func = null)
{
return $this->getSingle($func, false);
}
private function getWhereIteratorOrInnerIterator($func)
{
return $func === null ? $this->iterator : new WhereIterator($this->iterator, $func);
}
private function getSelectIteratorOrInnerIterator($func)
{
return $func === null ? $this->iterator : new SelectIterator($this->iterator, $func);
}
private function getSingle($func, $throw)
{
$source = $this->getWhereIteratorOrInnerIterator($func);
$count = 0;
$single = null;
foreach ($source as $stored) {
$count++;
if ($count > 1) {
throw new \RuntimeException("The input sequence contains more than 1 elements.");
}
$single = $stored;
}
if ($count == 0 && $throw) {
throw new \RuntimeException("The input sequence contains no matching element.");
}
return $single;
}
private function getFirst($func, $throw)
{
$source = $this->getWhereIteratorOrInnerIterator($func);
$count = 0;
$first = null;
foreach ($source as $stored) {
$count++;
$first = $stored;
break;
}
if ($count == 0 && $throw) {
throw new \RuntimeException("The input sequence contains no matching element.");
}
return $first;
}
private function getLast($func, $throw)
{
$source = $this->getWhereIteratorOrInnerIterator($func);
$count = 0;
$last = null;
foreach ($source as $stored) {
$count++;
$last = $stored;
}
if ($count == 0 && $throw) {
throw new \RuntimeException("The input sequence contains no matching element.");
}
return $last;
}
/**
* Creates an Array from this Linq object with key/value selector(s).
*
* @param callback $keySelector a func that returns the array-key for each element.
* @param callback $valueSelector a func that returns the array-value for each element.
*
* @return Array An array with all values.
*/
public function toArray($keySelector = null, $valueSelector = null)
{
if ($keySelector === null && $valueSelector === null) {
return iterator_to_array($this, false);
} elseif ($keySelector == null) {
return iterator_to_array(new SelectIterator($this->getIterator(), $valueSelector), false);
} else {
$array = array();
foreach ($this as $value) {
$key = $keySelector($value);
$array[$key] = $valueSelector == null ? $value : $valueSelector($value);
}
return $array;
}
}
/**
* Retrieves the iterator of this Linq class.
* @link http://php.net/manual/en/iteratoraggregate.getiterator.php
* @return Traversable An instance of an object implementing <b>Iterator</b> or
* <b>Traversable</b>
*/
public function getIterator()
{
return $this->iterator;
}
}
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