PHP SPL Data Structure notes summary

The main data structures used by PHP SPL (standard PHP Library) are: Doubly linked list (Spldoublylinkedlis), Stack (splstack), queue (Splqueue), Heap (Splheap), Dagen ( SPLMAXHEAP), small Gan (splminheap), Priority queue (Splpriorityqueue), fixed array (splfixedarray), Object Store (splstorageobject).

Spldoublylinkedlist

Data structure: (C code reference PHP7.0.0)

typedef struct _spl_ptr_llist_element {struct _spl_ptr_llist_element *prev;    struct _spl_ptr_llist_element *next;      int RC;    Number of citations void *data;      Data type} spl_ptr_llist_element;typedef struct _spl_ptr_llist {spl_ptr_llist_element *head;    Spl_ptr_llist_element *tail;    Spl_ptr_llist_dtor_func dtor;    Delete Element Reference-1 Spl_ptr_llist_ctor_func ctor;                        Create an element reference +1 int count;    Number of elements} spl_ptr_llist;struct _spl_dllist_object {zend_object std;    Spl_ptr_llist *llist;    int traverse_position;    Spl_ptr_llist_element *traverse_pointer;    Zval *retval;    int flags;    Zend_function *fptr_offset_get;    Zend_function *fptr_offset_set;    Zend_function *fptr_offset_has;    Zend_function *fptr_offset_del;    Zend_function *fptr_count; Zend_class_entry *ce_geT_iterator; HashTable *debug_info;};

Doubly linked list spldoublylinkedlist implements Iterator, arrayaccess, countable {/* method */public __construct (void) public void add (Mixed $index, mixed $newval) public mixed Bottom (void) public int count (void) public mixed current (void) public I NT Getiteratormode (void) public bool IsEmpty (void) public mixed key (void) public void next (void) public bool OFFSE Texists (mixed $index) public mixed offsetget (mixed $index) public void Offsetset (mixed $index, mixed $newval) publi c void Offsetunset (mixed $index) public mixed pops (void) public void prev (void) public void push (mixed $value) publ IC void Rewind (void) public string serialize (void) public void Setiteratormode (int. $mode) public mixed shift (void )      //Delete first element public mixed top (void) public void unserialize (string $serialized) public void unshift (mixed $value )   //Insert value into the first element, the original first element does not delete public bool valid (void)}

It is important to note that:

Add is a function added by the 5.5+ version, and the others are 5.3+

As can be seen from the data structure, although many functions contain a direct index element, the Outofrangeexception exception is thrown if it is not in scope, and the actual implementation time complexity is O (n).

Detailed functions can be found in the PHP official manual

The above describes the PHP SPL data structure Note Summary, including the aspects of the content, I hope that the PHP tutorial interested in a friend helpful.

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