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<?php
declare(strict_types = 1);
namespace DASPRiD\Enum;
use DASPRiD\Enum\Exception\ExpectationException;
use DASPRiD\Enum\Exception\IllegalArgumentException;
use IteratorAggregate;
use Serializable;
use Traversable;
/**
* A specialized map implementation for use with enum type keys.
*
* All of the keys in an enum map must come from a single enum type that is specified, when the map is created. Enum
* maps are represented internally as arrays. This representation is extremely compact and efficient.
*
* Enum maps are maintained in the natural order of their keys (the order in which the enum constants are declared).
* This is reflected in the iterators returned by the collection views {@see self::getIterator()} and
* {@see self::values()}.
*
* Iterators returned by the collection views are not consistent: They may or may not show the effects of modifications
* to the map that occur while the iteration is in progress.
*/
final class EnumMap implements Serializable, IteratorAggregate
{
/**
* The class name of the key.
*
* @var string
*/
private $keyType;
/**
* The type of the value.
*
* @var string
*/
private $valueType;
/**
* @var bool
*/
private $allowNullValues;
/**
* All of the constants comprising the enum, cached for performance.
*
* @var array<int, AbstractEnum>
*/
private $keyUniverse;
/**
* Array representation of this map. The ith element is the value to which universe[i] is currently mapped, or null
* if it isn't mapped to anything, or NullValue if it's mapped to null.
*
* @var array<int, mixed>
*/
private $values;
/**
* @var int
*/
private $size = 0;
/**
* Creates a new enum map.
*
* @param string $keyType the type of the keys, must extend AbstractEnum
* @param string $valueType the type of the values
* @param bool $allowNullValues whether to allow null values
* @throws IllegalArgumentException when key type does not extend AbstractEnum
*/
public function __construct(string $keyType, string $valueType, bool $allowNullValues)
{
if (! is_subclass_of($keyType, AbstractEnum::class)) {
throw new IllegalArgumentException(sprintf(
'Class %s does not extend %s',
$keyType,
AbstractEnum::class
));
}
$this->keyType = $keyType;
$this->valueType = $valueType;
$this->allowNullValues = $allowNullValues;
$this->keyUniverse = $keyType::values();
$this->values = array_fill(0, count($this->keyUniverse), null);
}
/**
* Checks whether the map types match the supplied ones.
*
* You should call this method when an EnumMap is passed to you and you want to ensure that it's made up of the
* correct types.
*
* @throws ExpectationException when supplied key type mismatches local key type
* @throws ExpectationException when supplied value type mismatches local value type
* @throws ExpectationException when the supplied map allows null values, abut should not
*/
public function expect(string $keyType, string $valueType, bool $allowNullValues) : void
{
if ($keyType !== $this->keyType) {
throw new ExpectationException(sprintf(
'Callee expected an EnumMap with key type %s, but got %s',
$keyType,
$this->keyType
));
}
if ($valueType !== $this->valueType) {
throw new ExpectationException(sprintf(
'Callee expected an EnumMap with value type %s, but got %s',
$keyType,
$this->keyType
));
}
if ($allowNullValues !== $this->allowNullValues) {
throw new ExpectationException(sprintf(
'Callee expected an EnumMap with nullable flag %s, but got %s',
($allowNullValues ? 'true' : 'false'),
($this->allowNullValues ? 'true' : 'false')
));
}
}
/**
* Returns the number of key-value mappings in this map.
*/
public function size() : int
{
return $this->size;
}
/**
* Returns true if this map maps one or more keys to the specified value.
*/
public function containsValue($value) : bool
{
return in_array($this->maskNull($value), $this->values, true);
}
/**
* Returns true if this map contains a mapping for the specified key.
*/
public function containsKey(AbstractEnum $key) : bool
{
$this->checkKeyType($key);
return null !== $this->values[$key->ordinal()];
}
/**
* Returns the value to which the specified key is mapped, or null if this map contains no mapping for the key.
*
* More formally, if this map contains a mapping from a key to a value, then this method returns the value;
* otherwise it returns null (there can be at most one such mapping).
*
* A return value of null does not necessarily indicate that the map contains no mapping for the key; it's also
* possible that hte map explicitly maps the key to null. The {@see self::containsKey()} operation may be used to
* distinguish these two cases.
*
* @return mixed
*/
public function get(AbstractEnum $key)
{
$this->checkKeyType($key);
return $this->unmaskNull($this->values[$key->ordinal()]);
}
/**
* Associates the specified value with the specified key in this map.
*
* If the map previously contained a mapping for this key, the old value is replaced.
*
* @return mixed the previous value associated with the specified key, or null if there was no mapping for the key.
* (a null return can also indicate that the map previously associated null with the specified key.)
* @throws IllegalArgumentException when the passed values does not match the internal value type
*/
public function put(AbstractEnum $key, $value)
{
$this->checkKeyType($key);
if (! $this->isValidValue($value)) {
throw new IllegalArgumentException(sprintf('Value is not of type %s', $this->valueType));
}
$index = $key->ordinal();
$oldValue = $this->values[$index];
$this->values[$index] = $this->maskNull($value);
if (null === $oldValue) {
++$this->size;
}
return $this->unmaskNull($oldValue);
}
/**
* Removes the mapping for this key frm this map if present.
*
* @return mixed the previous value associated with the specified key, or null if there was no mapping for the key.
* (a null return can also indicate that the map previously associated null with the specified key.)
*/
public function remove(AbstractEnum $key)
{
$this->checkKeyType($key);
$index = $key->ordinal();
$oldValue = $this->values[$index];
$this->values[$index] = null;
if (null !== $oldValue) {
--$this->size;
}
return $this->unmaskNull($oldValue);
}
/**
* Removes all mappings from this map.
*/
public function clear() : void
{
$this->values = array_fill(0, count($this->keyUniverse), null);
$this->size = 0;
}
/**
* Compares the specified map with this map for quality.
*
* Returns true if the two maps represent the same mappings.
*/
public function equals(self $other) : bool
{
if ($this === $other) {
return true;
}
if ($this->size !== $other->size) {
return false;
}
return $this->values === $other->values;
}
/**
* Returns the values contained in this map.
*
* The array will contain the values in the order their corresponding keys appear in the map, which is their natural
* order (the order in which the num constants are declared).
*/
public function values() : array
{
return array_values(array_map(function ($value) {
return $this->unmaskNull($value);
}, array_filter($this->values, function ($value) : bool {
return null !== $value;
})));
}
public function serialize() : string
{
$values = [];
foreach ($this->values as $ordinal => $value) {
if (null === $value) {
continue;
}
$values[$ordinal] = $this->unmaskNull($value);
}
return serialize([
'keyType' => $this->keyType,
'valueType' => $this->valueType,
'allowNullValues' => $this->allowNullValues,
'values' => $values,
]);
}
public function unserialize($serialized) : void
{
$data = unserialize($serialized);
$this->__construct($data['keyType'], $data['valueType'], $data['allowNullValues']);
foreach ($this->keyUniverse as $key) {
if (array_key_exists($key->ordinal(), $data['values'])) {
$this->put($key, $data['values'][$key->ordinal()]);
}
}
}
public function getIterator() : Traversable
{
foreach ($this->keyUniverse as $key) {
if (null === $this->values[$key->ordinal()]) {
continue;
}
yield $key => $this->unmaskNull($this->values[$key->ordinal()]);
}
}
private function maskNull($value)
{
if (null === $value) {
return NullValue::instance();
}
return $value;
}
private function unmaskNull($value)
{
if ($value instanceof NullValue) {
return null;
}
return $value;
}
/**
* @throws IllegalArgumentException when the passed key does not match the internal key type
*/
private function checkKeyType(AbstractEnum $key) : void
{
if (get_class($key) !== $this->keyType) {
throw new IllegalArgumentException(sprintf(
'Object of type %s is not the same type as %s',
get_class($key),
$this->keyType
));
}
}
private function isValidValue($value) : bool
{
if (null === $value) {
if ($this->allowNullValues) {
return true;
}
return false;
}
switch ($this->valueType) {
case 'mixed':
return true;
case 'bool':
case 'boolean':
return is_bool($value);
case 'int':
case 'integer':
return is_int($value);
case 'float':
case 'double':
return is_float($value);
case 'string':
return is_string($value);
case 'object':
return is_object($value);
case 'array':
return is_array($value);
}
return $value instanceof $this->valueType;
}
}
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