Update functions.php

Author: jakewhiteley

functions.php

@@ -1,11 +1,123 @@
 <?php
 
+/**
+ * Native-like helper functions for working with Sets
+ */
+
 /**
  * An additional function which allows a non OOP initialization of the Set object
  *
  * @param  mixed ...$args Values to initially add to the Set object
+ * @return \JakeWhiteley\PhpSets\Set
  */
 function set() 
 {
     return ( new \ReflectionClass('\JakeWhiteley\PhpSets\Set') )->newInstanceArgs( func_get_args() );
 }
+
+/**
+ * Returns a new Set which contains the unique items of both sets
+ * 
+ * @param  \JakeWhiteley\PhpSets\Set $set           The original set
+ * @param  \JakeWhiteley\PhpSets\Set $additionalSet The set to append
+ * @return \JakeWhiteley\PhpSets\Set A new set containing the merged items
+ */
+function set_merge( \JakeWhiteley\PhpSets\Set $set, \JakeWhiteley\PhpSets\Set $additionalSet )
+{
+	$iterator = $additionalSet->entries();
+
+	// create a copy of $set 
+	$merged = new \JakeWhiteley\PhpSets\Set();
+	$merged->exchangeArray( $set->values() );
+
+	// add values from $additionalSet if not present
+	while ( $iterator->valid() ) {
+	    if ( ! $set->has( $iterator->current() ) )
+	    	$merged->add( $iterator->current() );
+	    $iterator->next();
+	}
+	$iterator->rewind();
+
+	return $merged;
+}
+
+/**
+ * Returns a new Set object containing the common elements between two given sets
+ * 
+ * @param  \JakeWhiteley\PhpSets\Set $set           
+ * @param  \JakeWhiteley\PhpSets\Set $additionalSet
+ * @return \JakeWhiteley\PhpSets\Set
+ */
+function set_intersect( \JakeWhiteley\PhpSets\Set $set, \JakeWhiteley\PhpSets\Set $additionalSet )
+{
+	$iterator = $additionalSet->entries();
+	$intersect = new \JakeWhiteley\PhpSets\Set;
+
+	while ( $iterator->valid() ) {
+	    if ( $set->has( $iterator->current() ) )
+	    	$intersect->add( $iterator->current() );
+	    $iterator->next();
+	}
+	$iterator->rewind();
+
+	return $intersect;
+}
+
+/**
+ * Returns a new Set containing all uncommon items between the two given Sets
+ *
+ * @todo  This is not very efficient as it iterates both Sets completely
+ * 
+ * @param  \JakeWhiteley\PhpSets\Set $set           
+ * @param  \JakeWhiteley\PhpSets\Set $additionalSet
+ * @return \JakeWhiteley\PhpSets\Set
+ */
+function set_diff( \JakeWhiteley\PhpSets\Set $set, \JakeWhiteley\PhpSets\Set $additionalSet )
+{
+	$originalArray = $set->entries();
+	$iterator = $additionalSet->entries();
+	$intersect = new \JakeWhiteley\PhpSets\Set;
+
+	// check $set values
+	while ( $originalArray->valid() ) {
+	    if ( ! $additionalSet->has( $originalArray->current() ) ) 
+	    	$intersect->add( $originalArray->current() );
+	    $originalArray->next();
+	}
+
+	// check $additionalSet values
+	while ( $iterator->valid() ) {
+	    if ( ! $set->has( $iterator->current() ) ) 
+	    	$intersect->add( $iterator->current() );
+	    $iterator->next();
+	}
+	// reset both Set internal pointers
+	$originalArray->rewind();
+	$iterator->rewind();
+
+	return $intersect;
+}
+
+
+/**
+ * Checks if a given $additionalSet is a subset of $set
+ * All values should be present, but ordinality does not matter
+ * 
+ * @param  \JakeWhiteley\PhpSets\Set $set           The original Set to check against
+ * @param  \JakeWhiteley\PhpSets\Set $additionalSet The subset
+ * @return bool Whether $additionalSet was a subset of $set
+ */
+function set_subset( \JakeWhiteley\PhpSets\Set $set, \JakeWhiteley\PhpSets\Set $additionalSet )
+{
+	$iterator = $additionalSet->entries();
+	
+	// iterate through $additionalSet and return false is an uncommon value is present
+	while ( $iterator->valid() ) {
+	    if ( ! $set->has( $iterator->current() ) )
+	    	return false;
+	    $iterator->next();
+	}
+	$iterator->rewind();
+	
+	return true;
+}