Annotation of embedaddon/php/ext/spl/internal/spldoublylinkedlist.inc, revision 1.1
1.1 ! misho 1: <?php
! 2: /** @file spldoublylinkedlist.inc
! 3: * @ingroup SPL
! 4: * @brief class SplDoublyLinkedList
! 5: * @author Etienne Kneuss
! 6: * @date 2008 - 2009
! 7: *
! 8: * SPL - Standard PHP Library
! 9: */
! 10:
! 11: /** @ingroup SPL
! 12: * @brief Doubly Linked List
! 13: * @since PHP 5.3
! 14: *
! 15: * The SplDoublyLinkedList class provides the main functionalities of a
! 16: * doubly linked list (DLL).
! 17: * @note The following userland implementation of Iterator is a bit different
! 18: * from the internal one. Internally, iterators generated by nested
! 19: * foreachs are independent, while they share the same traverse pointer
! 20: * in userland.
! 21: */
! 22: class SplDoublyLinkedList implements Iterator, ArrayAccess, Countable
! 23: {
! 24: protected $_llist = array();
! 25: protected $_it_mode = 0;
! 26: protected $_it_pos = 0;
! 27:
! 28: /** Iterator mode
! 29: * @see setIteratorMode
! 30: */
! 31: const IT_MODE_LIFO = 0x00000002;
! 32:
! 33: /** Iterator mode
! 34: * @see setIteratorMode
! 35: */
! 36: const IT_MODE_FIFO = 0x00000000;
! 37:
! 38: /** Iterator mode
! 39: * @see setIteratorMode
! 40: */
! 41: const IT_MODE_KEEP = 0x00000000;
! 42:
! 43: /** Iterator mode
! 44: * @see setIteratorMode
! 45: */
! 46: const IT_MODE_DELETE = 0x00000001;
! 47:
! 48: /** @return the element popped from the end of the DLL.
! 49: * @throw RuntimeException If the datastructure is empty.
! 50: */
! 51: public function pop()
! 52: {
! 53: if (count($this->_llist) == 0) {
! 54: throw new RuntimeException("Can't pop from an empty datastructure");
! 55: }
! 56: return array_pop($this->_llist);
! 57: }
! 58:
! 59: /** @return the element shifted from the beginning of the DLL.
! 60: * @throw RuntimeException If the datastructure is empty.
! 61: */
! 62: public function shift()
! 63: {
! 64: if (count($this->_llist) == 0) {
! 65: throw new RuntimeException("Can't shift from an empty datastructure");
! 66: }
! 67: return array_shift($this->_llist);
! 68: }
! 69:
! 70: /** Pushes an element to the end of the DLL.
! 71: * @param $data variable to add to the DLL.
! 72: */
! 73: public function push($data)
! 74: {
! 75: array_push($this->_llist, $data);
! 76: return true;
! 77: }
! 78:
! 79: /** Adds an element to the beginning of the DLL.
! 80: * @param $data variable to add to the DLL.
! 81: */
! 82: public function unshift($data)
! 83: {
! 84: array_unshift($this->_llist, $data);
! 85: return true;
! 86: }
! 87:
! 88: /** @return the element at the beginning of the DLL.
! 89: */
! 90: public function top()
! 91: {
! 92: return end($this->_llist);
! 93: }
! 94:
! 95: /** @return the element at the end of the DLL.
! 96: */
! 97: public function bottom()
! 98: {
! 99: return reset($this->_llist);
! 100: }
! 101:
! 102: /** @return number elements in the DLL.
! 103: */
! 104: public function count()
! 105: {
! 106: return count($this->_llist);
! 107: }
! 108:
! 109: /** @return whether the DLL is empty.
! 110: */
! 111: public function isEmpty()
! 112: {
! 113: return ($this->count() == 0);
! 114: }
! 115:
! 116: /** Changes the iteration mode. There are two orthogonal sets of modes that
! 117: * can be set:
! 118: * - The direction of the iteration (either one or the other)
! 119: * - SplDoublyLnkedList::IT_MODE_LIFO (Stack style)
! 120: * - SplDoublyLnkedList::IT_MODE_FIFO (Queue style)
! 121: *
! 122: * - The behavior of the iterator (either one or the other)
! 123: * - SplDoublyLnkedList::IT_MODE_DELETE (Elements are deleted by the iterator)
! 124: * - SplDoublyLnkedList::IT_MODE_KEEP (Elements are traversed by the iterator)
! 125: *
! 126: * The default mode is 0 : SplDoublyLnkedList::IT_MODE_FIFO | SplDoublyLnkedList::IT_MODE_KEEP
! 127: *
! 128: * @param $mode new mode of iteration
! 129: */
! 130: public function setIteratorMode($mode)
! 131: {
! 132: $this->_it_mode = $mode;
! 133: }
! 134:
! 135: /** @return the current iteration mode
! 136: * @see setIteratorMode
! 137: */
! 138: public function getIteratorMode()
! 139: {
! 140: return $this->_it_mode;
! 141: }
! 142:
! 143: /** Rewind to top iterator as set in constructor
! 144: */
! 145: public function rewind()
! 146: {
! 147: if ($this->_it_mode & self::IT_MODE_LIFO) {
! 148: $this->_it_pos = count($this->_llist)-1;
! 149: } else {
! 150: $this->_it_pos = 0;
! 151: }
! 152: }
! 153:
! 154: /** @return whether iterator is valid
! 155: */
! 156: public function valid()
! 157: {
! 158: return array_key_exists($this->_it_pos, $this->_llist);
! 159: }
! 160:
! 161: /** @return current key
! 162: */
! 163: public function key()
! 164: {
! 165: return $this->_it_pos;
! 166: }
! 167:
! 168: /** @return current object
! 169: */
! 170: public function current()
! 171: {
! 172: return $this->_llist[$this->_it_pos];
! 173: }
! 174:
! 175: /** Forward to next element
! 176: */
! 177: public function next()
! 178: {
! 179: if ($this->_it_mode & self::IT_MODE_LIFO) {
! 180: if ($this->_it_mode & self::IT_MODE_DELETE) {
! 181: $this->pop();
! 182: }
! 183: $this->_it_pos--;
! 184: } else {
! 185: if ($this->_it_mode & self::IT_MODE_DELETE) {
! 186: $this->shift();
! 187: } else {
! 188: $this->_it_pos++;
! 189: }
! 190: }
! 191: }
! 192:
! 193: /** @return whether a certain offset exists in the DLL
! 194: *
! 195: * @param $offset The offset
! 196: * @throw OutOfRangeException If the offset is either invalid or out of
! 197: * range.
! 198: */
! 199: public function offsetExists($offset)
! 200: {
! 201: if (!is_numeric($offset)) {
! 202: throw new OutOfRangeException("Offset invalid or out of range");
! 203: } else {
! 204: return array_key_exists($offset, $this->_llist);
! 205: }
! 206: }
! 207:
! 208: /** @return the data at a certain offset in the DLL
! 209: *
! 210: * @param $offset The offset
! 211: * @throw OutOfRangeException If the offset is either invalid or out of
! 212: * range.
! 213: */
! 214: public function offsetGet($offset)
! 215: {
! 216: if ($this->_it_mode & self::IT_MODE_LIFO) {
! 217: $realOffset = count($this->_llist)-$offset;
! 218: } else {
! 219: $realOffset = $offset;
! 220: }
! 221:
! 222: if (!is_numeric($offset) || !array_key_exists($realOffset, $this->_llist)) {
! 223: throw new OutOfRangeException("Offset invalid or out of range");
! 224: } else {
! 225: return $this->_llist[$realOffset];
! 226: }
! 227: }
! 228:
! 229: /** Defines the data at a certain offset in the DLL
! 230: *
! 231: * @param $offset The offset
! 232: * @param $value New value
! 233: * @throw OutOfRangeException If the offset is either invalid or out of
! 234: * range.
! 235: */
! 236: public function offsetSet($offset, $value)
! 237: {
! 238: if ($offset === null) {
! 239: return $this->push($value);
! 240: }
! 241:
! 242: if ($this->_it_mode & self::IT_MODE_LIFO) {
! 243: $realOffset = count($this->_llist)-$offset;
! 244: } else {
! 245: $realOffset = $offset;
! 246: }
! 247:
! 248: if (!is_numeric($offset) || !array_key_exists($realOffset, $this->_llist)) {
! 249: throw new OutOfRangeException("Offset invalid or out of range");
! 250: } else {
! 251: $this->_llist[$realOffset] = $value;
! 252: }
! 253: }
! 254:
! 255: /** Unsets the element at a certain offset in the DLL
! 256: *
! 257: * @param $offset The offset
! 258: * @throw OutOfRangeException If the offset is either invalid or out of
! 259: * range.
! 260: */
! 261: public function offsetUnset($offset)
! 262: {
! 263: if ($this->_it_mode & self::IT_MODE_LIFO) {
! 264: $realOffset = count($this->_llist)-$offset;
! 265: } else {
! 266: $realOffset = $offset;
! 267: }
! 268:
! 269: if (!is_numeric($offset) || !array_key_exists($realOffset, $this->_llist)) {
! 270: throw new OutOfRangeException("Offset invalid or out of range");
! 271: } else {
! 272: array_splice($this->_llist, $realOffset, 1);
! 273: }
! 274: }
! 275: }
! 276:
! 277: ?>
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