/src/php-src/ext/spl/spl_dllist.c

Source
/*
   +----------------------------------------------------------------------+
   | Copyright © The PHP Group and Contributors.                          |
   +----------------------------------------------------------------------+
   | This source file is subject to the Modified BSD License that is      |
   | bundled with this package in the file LICENSE, and is available      |
   | through the World Wide Web at <https://www.php.net/license/>.        |
   |                                                                      |
   | SPDX-License-Identifier: BSD-3-Clause                                |
   +----------------------------------------------------------------------+
   | Authors: Etienne Kneuss <colder@php.net>                             |
   +----------------------------------------------------------------------+
 */

#ifdef HAVE_CONFIG_H
# include "config.h"
#endif

#include "php.h"
#include "zend_interfaces.h"
#include "zend_exceptions.h"
#include "zend_hash.h"

#include "ext/standard/php_var.h"
#include "zend_smart_str.h"
#include "spl_dllist.h"
#include "spl_dllist_arginfo.h"
#include "spl_exceptions.h"
#include "spl_functions.h" /* For spl_set_private_debug_info_property() */

static zend_object_handlers spl_handler_SplDoublyLinkedList;
PHPAPI zend_class_entry  *spl_ce_SplDoublyLinkedList;
PHPAPI zend_class_entry  *spl_ce_SplQueue;
PHPAPI zend_class_entry  *spl_ce_SplStack;

#define SPL_LLIST_RC(elem) Z_EXTRA((elem)->data)

#define SPL_LLIST_DELREF(elem) if (!--SPL_LLIST_RC(elem)) { \
  efree(elem); \
}

#define SPL_LLIST_CHECK_DELREF_EX(elem, on_free) if ((elem) && !--SPL_LLIST_RC(elem)) { \
  efree(elem); \
  on_free \
}

#define SPL_LLIST_CHECK_DELREF(elem) SPL_LLIST_CHECK_DELREF_EX(elem, ;)

#define SPL_LLIST_ADDREF(elem) SPL_LLIST_RC(elem)++
#define SPL_LLIST_CHECK_ADDREF(elem) if (elem) SPL_LLIST_RC(elem)++

#ifdef accept
#undef accept
#endif

typedef struct _spl_ptr_llist_element {
  struct _spl_ptr_llist_element *prev;
  struct _spl_ptr_llist_element *next;
  zval                           data;
} spl_ptr_llist_element;

typedef struct _spl_ptr_llist {
  spl_ptr_llist_element *head;
  spl_ptr_llist_element *tail;
  int count;
} spl_ptr_llist;

typedef struct _spl_dllist_object spl_dllist_object;
typedef struct _spl_dllist_it spl_dllist_it;

struct _spl_dllist_object {
  spl_ptr_llist         *llist;
  spl_ptr_llist_element *traverse_pointer;
  int                    traverse_position;
  int                    flags;
  zend_function         *fptr_count;
  zend_object            std;
};

/* define an overloaded iterator structure */
struct _spl_dllist_it {
  zend_object_iterator   intern;
  spl_ptr_llist_element *traverse_pointer;
  int                    traverse_position;
  int                    flags;
};

#define spl_dllist_from_obj(obj) ZEND_CONTAINER_OF(obj, spl_dllist_object, std)

#define Z_SPLDLLIST_P(zv)  spl_dllist_from_obj(Z_OBJ_P((zv)))

static spl_ptr_llist *spl_ptr_llist_init(void) /* {{{ */
{
  spl_ptr_llist *llist = emalloc(sizeof(spl_ptr_llist));

  llist->head  = NULL;
  llist->tail  = NULL;
  llist->count = 0;

  return llist;
}
/* }}} */

static zend_long spl_ptr_llist_count(spl_ptr_llist *llist) /* {{{ */
{
  return (zend_long)llist->count;
}
/* }}} */

static void spl_ptr_llist_destroy(spl_ptr_llist *llist) /* {{{ */
{
  spl_ptr_llist_element *current = llist->head, *next;

  while (current) {
    next = current->next;
    zval_ptr_dtor(&current->data);
    SPL_LLIST_DELREF(current);
    current = next;
  }

  efree(llist);
}
/* }}} */

static spl_ptr_llist_element *spl_ptr_llist_offset(spl_ptr_llist *llist, zend_long offset, int backward) /* {{{ */
{

  spl_ptr_llist_element *current;
  int pos = 0;

  if (backward) {
    current = llist->tail;
  } else {
    current = llist->head;
  }

  while (current && pos < offset) {
    pos++;
    if (backward) {
      current = current->prev;
    } else {
      current = current->next;
    }
  }

  return current;
}
/* }}} */

static void spl_ptr_llist_unshift(spl_ptr_llist *llist, zval *data) /* {{{ */
{
  spl_ptr_llist_element *elem = emalloc(sizeof(spl_ptr_llist_element));

  elem->prev = NULL;
  elem->next = llist->head;
  ZVAL_COPY(&elem->data, data);
  SPL_LLIST_RC(elem) = 1;

  if (llist->head) {
    llist->head->prev = elem;
  } else {
    llist->tail = elem;
  }

  llist->head = elem;
  llist->count++;
}
/* }}} */

static void spl_ptr_llist_push(spl_ptr_llist *llist, zval *data) /* {{{ */
{
  spl_ptr_llist_element *elem = emalloc(sizeof(spl_ptr_llist_element));

  elem->prev = llist->tail;
  elem->next = NULL;
  ZVAL_COPY(&elem->data, data);
  SPL_LLIST_RC(elem) = 1;

  if (llist->tail) {
    llist->tail->next = elem;
  } else {
    llist->head = elem;
  }

  llist->tail = elem;
  llist->count++;
}
/* }}} */

static void spl_ptr_llist_pop(spl_ptr_llist *llist, zval *ret) /* {{{ */
{
  spl_ptr_llist_element    *tail = llist->tail;

  if (tail == NULL) {
    ZVAL_UNDEF(ret);
    return;
  }

  if (tail->prev) {
    tail->prev->next = NULL;
  } else {
    llist->head = NULL;
  }

  llist->tail = tail->prev;
  llist->count--;
  ZVAL_COPY_VALUE(ret, &tail->data);
  ZVAL_UNDEF(&tail->data);

  tail->prev = NULL;

  SPL_LLIST_DELREF(tail);
}
/* }}} */

static zval *spl_ptr_llist_last(spl_ptr_llist *llist) /* {{{ */
{
  spl_ptr_llist_element *tail = llist->tail;

  if (tail == NULL) {
    return NULL;
  } else {
    return &tail->data;
  }
}
/* }}} */

static zval *spl_ptr_llist_first(spl_ptr_llist *llist) /* {{{ */
{
  spl_ptr_llist_element *head = llist->head;

  if (head == NULL) {
    return NULL;
  } else {
    return &head->data;
  }
}
/* }}} */

static void spl_ptr_llist_shift(spl_ptr_llist *llist, zval *ret) /* {{{ */
{
  spl_ptr_llist_element   *head = llist->head;

  if (head == NULL) {
    ZVAL_UNDEF(ret);
    return;
  }

  if (head->next) {
    head->next->prev = NULL;
  } else {
    llist->tail = NULL;
  }

  llist->head = head->next;
  llist->count--;
  ZVAL_COPY_VALUE(ret, &head->data);
  ZVAL_UNDEF(&head->data);

  head->next = NULL;

  SPL_LLIST_DELREF(head);
}
/* }}} */

static void spl_ptr_llist_copy(spl_ptr_llist *from, spl_ptr_llist *to) /* {{{ */
{
  spl_ptr_llist_element *current = from->head, *next;

  while (current) {
    next = current->next;
    spl_ptr_llist_push(to, &current->data);
    current = next;
  }

}
/* }}} */

/* }}} */

static void spl_dllist_object_free_storage(zend_object *object) /* {{{ */
{
  spl_dllist_object *intern = spl_dllist_from_obj(object);
  zval tmp;

  zend_object_std_dtor(&intern->std);

  if (intern->llist) {
    while (intern->llist->count > 0) {
      spl_ptr_llist_pop(intern->llist, &tmp);
      zval_ptr_dtor(&tmp);
    }
    spl_ptr_llist_destroy(intern->llist);
  }
  SPL_LLIST_CHECK_DELREF(intern->traverse_pointer);
}
/* }}} */

static zend_object *spl_dllist_object_new_ex(zend_class_entry *class_type, zend_object *orig, int clone_orig) /* {{{ */
{
  spl_dllist_object *intern;
  const zend_class_entry *parent = class_type;
  int                inherited = 0;

  intern = zend_object_alloc(sizeof(spl_dllist_object), parent);

  zend_object_std_init(&intern->std, class_type);
  object_properties_init(&intern->std, class_type);

  intern->flags = 0;
  intern->traverse_position = 0;

  if (orig) {
    const spl_dllist_object *other = spl_dllist_from_obj(orig);

    if (clone_orig) {
      intern->llist = spl_ptr_llist_init();
      spl_ptr_llist_copy(other->llist, intern->llist);
      intern->traverse_pointer  = intern->llist->head;
      SPL_LLIST_CHECK_ADDREF(intern->traverse_pointer);
    } else {
      intern->llist = other->llist;
      intern->traverse_pointer  = intern->llist->head;
      SPL_LLIST_CHECK_ADDREF(intern->traverse_pointer);
    }

    intern->flags = other->flags;
  } else {
    intern->llist = spl_ptr_llist_init();
    intern->traverse_pointer  = intern->llist->head;
    SPL_LLIST_CHECK_ADDREF(intern->traverse_pointer);
  }

  while (parent) {
    if (parent == spl_ce_SplStack) {
      intern->flags |= (SPL_DLLIST_IT_FIX | SPL_DLLIST_IT_LIFO);
    } else if (parent == spl_ce_SplQueue) {
      intern->flags |= SPL_DLLIST_IT_FIX;
    }

    if (parent == spl_ce_SplDoublyLinkedList) {
      break;
    }

    parent = parent->parent;
    inherited = 1;
  }

  ZEND_ASSERT(parent);

  if (inherited) {
    /* Find count() method */
    intern->fptr_count = zend_hash_find_ptr(&class_type->function_table, ZSTR_KNOWN(ZEND_STR_COUNT));
    if (intern->fptr_count->common.scope == parent) {
      intern->fptr_count = NULL;
    }
  }

  return &intern->std;
}
/* }}} */

static zend_object *spl_dllist_object_new(zend_class_entry *class_type) /* {{{ */
{
  return spl_dllist_object_new_ex(class_type, NULL, 0);
}
/* }}} */

static zend_object *spl_dllist_object_clone(zend_object *old_object) /* {{{ */
{
  zend_object *new_object = spl_dllist_object_new_ex(old_object->ce, old_object, 1);

  zend_objects_clone_members(new_object, old_object);

  return new_object;
}
/* }}} */

static zend_result spl_dllist_object_count_elements(zend_object *object, zend_long *count) /* {{{ */
{
  spl_dllist_object *intern = spl_dllist_from_obj(object);

  if (intern->fptr_count) {
    zval rv;
    zend_call_method_with_0_params(object, intern->std.ce, &intern->fptr_count, "count", &rv);
    if (!Z_ISUNDEF(rv)) {
      *count = zval_get_long(&rv);
      zval_ptr_dtor(&rv);
      return SUCCESS;
    }
    *count = 0;
    return FAILURE;
  }

  *count = spl_ptr_llist_count(intern->llist);
  return SUCCESS;
}
/* }}} */

static inline HashTable* spl_dllist_object_get_debug_info(zend_object *obj) /* {{{{ */
{
  spl_dllist_object     *intern  = spl_dllist_from_obj(obj);
  spl_ptr_llist_element *current = intern->llist->head;
  zval tmp, dllist_array;
  HashTable *debug_info;
  HashTable *properties = zend_std_get_properties_ex(&intern->std);

  /* +2 As we are adding 2 additional key-entries */
  debug_info = zend_new_array(zend_hash_num_elements(properties) + 2);
  zend_hash_copy(debug_info, properties, (copy_ctor_func_t) zval_add_ref);

  ZVAL_LONG(&tmp, intern->flags);
  spl_set_private_debug_info_property(spl_ce_SplDoublyLinkedList, "flags", strlen("flags"), debug_info, &tmp);

  array_init(&dllist_array);

  zend_ulong index = 0;
  while (current) {
    spl_ptr_llist_element *next = current->next;

    add_index_zval(&dllist_array, index, &current->data);
    if (Z_REFCOUNTED(current->data)) {
      Z_ADDREF(current->data);
    }
    index++;

    current = next;
  }

  spl_set_private_debug_info_property(spl_ce_SplDoublyLinkedList, "dllist", strlen("dllist"), debug_info, &dllist_array);

  return debug_info;
}
/* }}}} */

static HashTable *spl_dllist_object_get_gc(zend_object *obj, zval **gc_data, int *gc_data_count) /* {{{ */
{
  spl_dllist_object *intern = spl_dllist_from_obj(obj);
  zend_get_gc_buffer *gc_buffer = zend_get_gc_buffer_create();
  spl_ptr_llist_element *current = intern->llist->head;

  while (current) {
    zend_get_gc_buffer_add_zval(gc_buffer, &current->data);
    current = current->next;
  }

  zend_get_gc_buffer_use(gc_buffer, gc_data, gc_data_count);
  return zend_std_get_properties(obj);
}
/* }}} */

/* {{{ Push $value on the SplDoublyLinkedList */
PHP_METHOD(SplDoublyLinkedList, push)
{
  zval *value;
  spl_dllist_object *intern;

  if (zend_parse_parameters(ZEND_NUM_ARGS(), "z", &value) == FAILURE) {
    RETURN_THROWS();
  }

  intern = Z_SPLDLLIST_P(ZEND_THIS);
  spl_ptr_llist_push(intern->llist, value);
}
/* }}} */

/* {{{ Unshift $value on the SplDoublyLinkedList */
PHP_METHOD(SplDoublyLinkedList, unshift)
{
  zval *value;
  spl_dllist_object *intern;

  if (zend_parse_parameters(ZEND_NUM_ARGS(), "z", &value) == FAILURE) {
    RETURN_THROWS();
  }

  intern = Z_SPLDLLIST_P(ZEND_THIS);
  spl_ptr_llist_unshift(intern->llist, value);
}
/* }}} */

/* {{{ Pop an element out of the SplDoublyLinkedList */
PHP_METHOD(SplDoublyLinkedList, pop)
{
  spl_dllist_object *intern;

  ZEND_PARSE_PARAMETERS_NONE();

  intern = Z_SPLDLLIST_P(ZEND_THIS);
  spl_ptr_llist_pop(intern->llist, return_value);

  if (Z_ISUNDEF_P(return_value)) {
    zend_throw_exception(spl_ce_RuntimeException, "Can't pop from an empty datastructure", 0);
    RETURN_THROWS();
  }
}
/* }}} */

/* {{{ Shift an element out of the SplDoublyLinkedList */
PHP_METHOD(SplDoublyLinkedList, shift)
{
  spl_dllist_object *intern;

  ZEND_PARSE_PARAMETERS_NONE();

  intern = Z_SPLDLLIST_P(ZEND_THIS);
  spl_ptr_llist_shift(intern->llist, return_value);

  if (Z_ISUNDEF_P(return_value)) {
    zend_throw_exception(spl_ce_RuntimeException, "Can't shift from an empty datastructure", 0);
    RETURN_THROWS();
  }
}
/* }}} */

/* {{{ Peek at the top element of the SplDoublyLinkedList */
PHP_METHOD(SplDoublyLinkedList, top)
{
  zval *value;
  spl_dllist_object *intern;

  ZEND_PARSE_PARAMETERS_NONE();

  intern = Z_SPLDLLIST_P(ZEND_THIS);
  value = spl_ptr_llist_last(intern->llist);

  if (value == NULL || Z_ISUNDEF_P(value)) {
    zend_throw_exception(spl_ce_RuntimeException, "Can't peek at an empty datastructure", 0);
    RETURN_THROWS();
  }

  RETURN_COPY_DEREF(value);
}
/* }}} */

/* {{{ Peek at the bottom element of the SplDoublyLinkedList */
PHP_METHOD(SplDoublyLinkedList, bottom)
{
  zval *value;
  spl_dllist_object *intern;

  ZEND_PARSE_PARAMETERS_NONE();

  intern = Z_SPLDLLIST_P(ZEND_THIS);
  value  = spl_ptr_llist_first(intern->llist);

  if (value == NULL || Z_ISUNDEF_P(value)) {
    zend_throw_exception(spl_ce_RuntimeException, "Can't peek at an empty datastructure", 0);
    RETURN_THROWS();
  }

  RETURN_COPY_DEREF(value);
}
/* }}} */

/* {{{ Return the number of elements in the datastructure. */
PHP_METHOD(SplDoublyLinkedList, count)
{
  zend_long count;
  spl_dllist_object *intern = Z_SPLDLLIST_P(ZEND_THIS);

  ZEND_PARSE_PARAMETERS_NONE();

  count = spl_ptr_llist_count(intern->llist);
  RETURN_LONG(count);
}
/* }}} */

/* {{{ Return true if the SplDoublyLinkedList is empty. */
PHP_METHOD(SplDoublyLinkedList, isEmpty)
{
  zend_long count;

  ZEND_PARSE_PARAMETERS_NONE();

  spl_dllist_object_count_elements(Z_OBJ_P(ZEND_THIS), &count);
  RETURN_BOOL(count == 0);
}
/* }}} */

/* {{{ Set the mode of iteration */
PHP_METHOD(SplDoublyLinkedList, setIteratorMode)
{
  zend_long value;
  spl_dllist_object *intern;

  if (zend_parse_parameters(ZEND_NUM_ARGS(), "l", &value) == FAILURE) {
    RETURN_THROWS();
  }

  intern = Z_SPLDLLIST_P(ZEND_THIS);

  if ((intern->flags & SPL_DLLIST_IT_FIX)
    && (intern->flags & SPL_DLLIST_IT_LIFO) != (value & SPL_DLLIST_IT_LIFO)) {
    zend_throw_exception(spl_ce_RuntimeException, "Iterators' LIFO/FIFO modes for SplStack/SplQueue objects are frozen", 0);
    RETURN_THROWS();
  }

  intern->flags = (value & SPL_DLLIST_IT_MASK) | (intern->flags & SPL_DLLIST_IT_FIX);

  RETURN_LONG(intern->flags);
}
/* }}} */

/* {{{ Return the mode of iteration */
PHP_METHOD(SplDoublyLinkedList, getIteratorMode)
{
  spl_dllist_object *intern;

  ZEND_PARSE_PARAMETERS_NONE();

  intern = Z_SPLDLLIST_P(ZEND_THIS);

  RETURN_LONG(intern->flags);
}
/* }}} */

/* {{{ Returns whether the requested $index exists. */
PHP_METHOD(SplDoublyLinkedList, offsetExists)
{
  spl_dllist_object *intern;
  zend_long index;

  if (zend_parse_parameters(ZEND_NUM_ARGS(), "l", &index) == FAILURE) {
    RETURN_THROWS();
  }

  intern = Z_SPLDLLIST_P(ZEND_THIS);

  RETURN_BOOL(index >= 0 && index < intern->llist->count);
} /* }}} */

/* {{{ Returns the value at the specified $index. */
PHP_METHOD(SplDoublyLinkedList, offsetGet)
{
  zend_long                   index;
  spl_dllist_object     *intern;
  spl_ptr_llist_element *element;

  if (zend_parse_parameters(ZEND_NUM_ARGS(), "l", &index) == FAILURE) {
    RETURN_THROWS();
  }

  intern = Z_SPLDLLIST_P(ZEND_THIS);

  if (index < 0 || index >= intern->llist->count) {
    zend_argument_error(spl_ce_OutOfRangeException, 1, "is out of range");
    RETURN_THROWS();
  }

  element = spl_ptr_llist_offset(intern->llist, index, intern->flags & SPL_DLLIST_IT_LIFO);
  if (element == NULL) {
    zend_argument_error(spl_ce_OutOfRangeException, 1, "is an invalid offset");
    RETURN_THROWS();
  }

  RETURN_COPY_DEREF(&element->data);
} /* }}} */

/* {{{ Sets the value at the specified $index to $newval. */
PHP_METHOD(SplDoublyLinkedList, offsetSet)
{
  zend_long index;
  bool index_is_null = true;
  zval *value;
  spl_dllist_object *intern;

  if (zend_parse_parameters(ZEND_NUM_ARGS(), "l!z", &index, &index_is_null, &value) == FAILURE) {
    RETURN_THROWS();
  }

  intern = Z_SPLDLLIST_P(ZEND_THIS);

  if (index_is_null) {
    /* $obj[] = ... */
    spl_ptr_llist_push(intern->llist, value);
  } else {
    /* $obj[$foo] = ... */
    spl_ptr_llist_element *element;

    if (index < 0 || index >= intern->llist->count) {
      zend_argument_error(spl_ce_OutOfRangeException, 1, "is out of range");
      RETURN_THROWS();
    }

    element = spl_ptr_llist_offset(intern->llist, index, intern->flags & SPL_DLLIST_IT_LIFO);

    if (element != NULL) {
      /* the element is replaced, delref the old one as in
       * SplDoublyLinkedList::pop() */
      zval garbage;
      ZVAL_COPY_VALUE(&garbage, &element->data);
      ZVAL_COPY(&element->data, value);
      zval_ptr_dtor(&garbage);
    } else {
      zval_ptr_dtor(value);
      zend_argument_error(spl_ce_OutOfRangeException, 1, "is an invalid offset");
      RETURN_THROWS();
    }
  }
} /* }}} */

/* {{{ Unsets the value at the specified $index. */
PHP_METHOD(SplDoublyLinkedList, offsetUnset)
{
  zend_long             index;
  spl_dllist_object     *intern;
  spl_ptr_llist_element *element;
  spl_ptr_llist         *llist;

  if (zend_parse_parameters(ZEND_NUM_ARGS(), "l", &index) == FAILURE) {
    RETURN_THROWS();
  }

  intern = Z_SPLDLLIST_P(ZEND_THIS);
  llist  = intern->llist;

  if (index < 0 || index >= intern->llist->count) {
    zend_argument_error(spl_ce_OutOfRangeException, 1, "is out of range");
    RETURN_THROWS();
  }

  element = spl_ptr_llist_offset(intern->llist, index, intern->flags & SPL_DLLIST_IT_LIFO);

  if (element != NULL) {
    /* disconnect the neighbours */
    if (element->prev) {
      element->prev->next = element->next;
    }
    if (element->next) {
      element->next->prev = element->prev;
    }

    /* take care of head/tail */
    if (element == llist->head) {
      llist->head = element->next;
    }

    if (element == llist->tail) {
      llist->tail = element->prev;
    }

    /* Keep consistency if element is kept alive. */
    element->prev = NULL;
    element->next = NULL;

    /* finally, delete the element */
    llist->count--;

    if (intern->traverse_pointer == element) {
      SPL_LLIST_DELREF(element);
      intern->traverse_pointer = NULL;
    }

    zval_ptr_dtor(&element->data);
    ZVAL_UNDEF(&element->data);

    SPL_LLIST_DELREF(element);
  } else {
    zend_argument_error(spl_ce_OutOfRangeException, 1, "is an invalid offset");
    RETURN_THROWS();
  }
} /* }}} */

static void spl_dllist_it_dtor(zend_object_iterator *iter) /* {{{ */
{
  spl_dllist_it *iterator = (spl_dllist_it *)iter;

  SPL_LLIST_CHECK_DELREF(iterator->traverse_pointer);

  zval_ptr_dtor(&iterator->intern.data);
}
/* }}} */

static void spl_dllist_it_helper_rewind(spl_ptr_llist_element **traverse_pointer_ptr, int *traverse_position_ptr, spl_ptr_llist *llist, int flags) /* {{{ */
{
  SPL_LLIST_CHECK_DELREF(*traverse_pointer_ptr);

  if (flags & SPL_DLLIST_IT_LIFO) {
    *traverse_position_ptr = llist->count-1;
    *traverse_pointer_ptr  = llist->tail;
  } else {
    *traverse_position_ptr = 0;
    *traverse_pointer_ptr  = llist->head;
  }

  SPL_LLIST_CHECK_ADDREF(*traverse_pointer_ptr);
}
/* }}} */

static void spl_dllist_it_helper_move_forward(spl_ptr_llist_element **traverse_pointer_ptr, int *traverse_position_ptr, spl_ptr_llist *llist, int flags) /* {{{ */
{
  if (*traverse_pointer_ptr) {
    spl_ptr_llist_element *old = *traverse_pointer_ptr;

    if (flags & SPL_DLLIST_IT_LIFO) {
      *traverse_pointer_ptr = old->prev;
      SPL_LLIST_CHECK_ADDREF(*traverse_pointer_ptr);
      (*traverse_position_ptr)--;

      if (flags & SPL_DLLIST_IT_DELETE) {
        zval prev;
        spl_ptr_llist_pop(llist, &prev);

        zval_ptr_dtor(&prev);
      }
    } else {
      *traverse_pointer_ptr = old->next;
      SPL_LLIST_CHECK_ADDREF(*traverse_pointer_ptr);

      if (flags & SPL_DLLIST_IT_DELETE) {
        zval prev;
        spl_ptr_llist_shift(llist, &prev);

        zval_ptr_dtor(&prev);
      } else {
        (*traverse_position_ptr)++;
      }
    }

    SPL_LLIST_DELREF(old);
  }
}
/* }}} */

static void spl_dllist_it_rewind(zend_object_iterator *iter) /* {{{ */
{
  spl_dllist_it *iterator = (spl_dllist_it *)iter;
  spl_dllist_object *object = Z_SPLDLLIST_P(&iter->data);
  spl_ptr_llist *llist = object->llist;

  spl_dllist_it_helper_rewind(&iterator->traverse_pointer, &iterator->traverse_position, llist, iterator->flags);
}
/* }}} */

static zend_result spl_dllist_it_valid(zend_object_iterator *iter) /* {{{ */
{
  spl_dllist_it         *iterator = (spl_dllist_it *)iter;
  spl_ptr_llist_element *element  = iterator->traverse_pointer;

  return (element != NULL ? SUCCESS : FAILURE);
}
/* }}} */

static zval *spl_dllist_it_get_current_data(zend_object_iterator *iter) /* {{{ */
{
  spl_dllist_it         *iterator = (spl_dllist_it *)iter;
  spl_ptr_llist_element *element  = iterator->traverse_pointer;

  if (element == NULL || Z_ISUNDEF(element->data)) {
    return NULL;
  }

  return &element->data;
}
/* }}} */

static void spl_dllist_it_get_current_key(zend_object_iterator *iter, zval *key) /* {{{ */
{
  spl_dllist_it *iterator = (spl_dllist_it *)iter;

  ZVAL_LONG(key, iterator->traverse_position);
}
/* }}} */

static void spl_dllist_it_move_forward(zend_object_iterator *iter) /* {{{ */
{
  spl_dllist_it *iterator = (spl_dllist_it *)iter;
  spl_dllist_object *object = Z_SPLDLLIST_P(&iter->data);

  spl_dllist_it_helper_move_forward(&iterator->traverse_pointer, &iterator->traverse_position, object->llist, iterator->flags);
}
/* }}} */

/* {{{ Return current array key */
PHP_METHOD(SplDoublyLinkedList, key)
{
  spl_dllist_object *intern = Z_SPLDLLIST_P(ZEND_THIS);

  ZEND_PARSE_PARAMETERS_NONE();

  RETURN_LONG(intern->traverse_position);
}
/* }}} */

/* {{{ Move to next entry */
PHP_METHOD(SplDoublyLinkedList, prev)
{
  spl_dllist_object *intern = Z_SPLDLLIST_P(ZEND_THIS);

  ZEND_PARSE_PARAMETERS_NONE();

  spl_dllist_it_helper_move_forward(&intern->traverse_pointer, &intern->traverse_position, intern->llist, intern->flags ^ SPL_DLLIST_IT_LIFO);
}
/* }}} */

/* {{{ Move to next entry */
PHP_METHOD(SplDoublyLinkedList, next)
{
  spl_dllist_object *intern = Z_SPLDLLIST_P(ZEND_THIS);

  ZEND_PARSE_PARAMETERS_NONE();

  spl_dllist_it_helper_move_forward(&intern->traverse_pointer, &intern->traverse_position, intern->llist, intern->flags);
}
/* }}} */

/* {{{ Check whether the datastructure contains more entries */
PHP_METHOD(SplDoublyLinkedList, valid)
{
  spl_dllist_object *intern = Z_SPLDLLIST_P(ZEND_THIS);

  ZEND_PARSE_PARAMETERS_NONE();

  RETURN_BOOL(intern->traverse_pointer != NULL);
}
/* }}} */

/* {{{ Rewind the datastructure back to the start */
PHP_METHOD(SplDoublyLinkedList, rewind)
{
  spl_dllist_object *intern = Z_SPLDLLIST_P(ZEND_THIS);

  ZEND_PARSE_PARAMETERS_NONE();

  spl_dllist_it_helper_rewind(&intern->traverse_pointer, &intern->traverse_position, intern->llist, intern->flags);
}
/* }}} */

/* {{{ Return current datastructure entry */
PHP_METHOD(SplDoublyLinkedList, current)
{
  spl_dllist_object     *intern  = Z_SPLDLLIST_P(ZEND_THIS);
  spl_ptr_llist_element *element = intern->traverse_pointer;

  ZEND_PARSE_PARAMETERS_NONE();

  if (element == NULL || Z_ISUNDEF(element->data)) {
    RETURN_NULL();
  } else {
    RETURN_COPY_DEREF(&element->data);
  }
}
/* }}} */

/* {{{ Serializes storage */
PHP_METHOD(SplDoublyLinkedList, serialize)
{
  spl_dllist_object     *intern   = Z_SPLDLLIST_P(ZEND_THIS);
  smart_str              buf      = {0};
  spl_ptr_llist_element *current  = intern->llist->head, *next;
  zval                   flags;
  php_serialize_data_t   var_hash;

  ZEND_PARSE_PARAMETERS_NONE();

  PHP_VAR_SERIALIZE_INIT(var_hash);

  /* flags */
  ZVAL_LONG(&flags, intern->flags);
  php_var_serialize(&buf, &flags, &var_hash);

  /* elements */
  while (current) {
    smart_str_appendc(&buf, ':');
    next = current->next;

    SPL_LLIST_CHECK_ADDREF(next);

    php_var_serialize(&buf, &current->data, &var_hash);

    SPL_LLIST_CHECK_DELREF_EX(next, break;);

    current = next;
  }

  /* done */
  PHP_VAR_SERIALIZE_DESTROY(var_hash);

  RETURN_STR(smart_str_extract(&buf));
} /* }}} */

/* {{{ Unserializes storage */
PHP_METHOD(SplDoublyLinkedList, unserialize)
{
  spl_dllist_object *intern = Z_SPLDLLIST_P(ZEND_THIS);
  zval *flags, *elem;
  char *buf;
  size_t buf_len;
  const unsigned char *p, *s;
  php_unserialize_data_t var_hash;

  if (zend_parse_parameters(ZEND_NUM_ARGS(), "s", &buf, &buf_len) == FAILURE) {
    RETURN_THROWS();
  }

  if (buf_len == 0) {
    return;
  }

  while (intern->llist->count > 0) {
    zval tmp;
    spl_ptr_llist_pop(intern->llist, &tmp);
    zval_ptr_dtor(&tmp);
  }

  s = p = (const unsigned char*)buf;
  PHP_VAR_UNSERIALIZE_INIT(var_hash);

  /* flags */
  flags = var_tmp_var(&var_hash);
  if (!php_var_unserialize(flags, &p, s + buf_len, &var_hash) || Z_TYPE_P(flags) != IS_LONG) {
    goto error;
  }

  intern->flags = (int)Z_LVAL_P(flags);

  /* elements */
  while(*p == ':') {
    ++p;
    elem = var_tmp_var(&var_hash);
    if (!php_var_unserialize(elem, &p, s + buf_len, &var_hash)) {
      goto error;
    }
    var_push_dtor(&var_hash, elem);

    spl_ptr_llist_push(intern->llist, elem);
  }

  if (*p != '\0') {
    goto error;
  }

  PHP_VAR_UNSERIALIZE_DESTROY(var_hash);
  return;

error:
  PHP_VAR_UNSERIALIZE_DESTROY(var_hash);
  zend_throw_exception_ex(spl_ce_UnexpectedValueException, 0, "Error at offset %zd of %zd bytes", ((char*)p - buf), buf_len);
  RETURN_THROWS();

} /* }}} */

/* {{{ */
PHP_METHOD(SplDoublyLinkedList, __serialize)
{
  spl_dllist_object *intern = Z_SPLDLLIST_P(ZEND_THIS);
  spl_ptr_llist_element *current = intern->llist->head;
  zval tmp;

  ZEND_PARSE_PARAMETERS_NONE();

  array_init(return_value);

  /* flags */
  ZVAL_LONG(&tmp, intern->flags);
  zend_hash_next_index_insert(Z_ARRVAL_P(return_value), &tmp);

  /* elements */
  array_init_size(&tmp, intern->llist->count);
  while (current) {
    zend_hash_next_index_insert(Z_ARRVAL(tmp), &current->data);
    Z_TRY_ADDREF(current->data);
    current = current->next;
  }
  zend_hash_next_index_insert(Z_ARRVAL_P(return_value), &tmp);

  /* members */
  ZVAL_ARR(&tmp, zend_proptable_to_symtable(
    zend_std_get_properties(&intern->std), /* always_duplicate */ 1));
  zend_hash_next_index_insert(Z_ARRVAL_P(return_value), &tmp);
} /* }}} */

/* {{{ */
PHP_METHOD(SplDoublyLinkedList, __unserialize) {
  spl_dllist_object *intern = Z_SPLDLLIST_P(ZEND_THIS);
  HashTable *data;
  zval *flags_zv, *storage_zv, *members_zv, *elem;

  if (zend_parse_parameters(ZEND_NUM_ARGS(), "h", &data) == FAILURE) {
    RETURN_THROWS();
  }

  flags_zv = zend_hash_index_find(data, 0);
  storage_zv = zend_hash_index_find(data, 1);
  members_zv = zend_hash_index_find(data, 2);
  if (!flags_zv || !storage_zv || !members_zv ||
      Z_TYPE_P(flags_zv) != IS_LONG || Z_TYPE_P(storage_zv) != IS_ARRAY ||
      Z_TYPE_P(members_zv) != IS_ARRAY) {
    zend_throw_exception(spl_ce_UnexpectedValueException,
      "Incomplete or ill-typed serialization data", 0);
    RETURN_THROWS();
  }

  intern->flags = (int) Z_LVAL_P(flags_zv);

  ZEND_HASH_FOREACH_VAL(Z_ARRVAL_P(storage_zv), elem) {
    spl_ptr_llist_push(intern->llist, elem);
  } ZEND_HASH_FOREACH_END();

  object_properties_load(&intern->std, Z_ARRVAL_P(members_zv));
} /* }}} */

/* {{{ Inserts a new entry before the specified $index consisting of $newval. */
PHP_METHOD(SplDoublyLinkedList, add)
{
  zval                  *value;
  spl_dllist_object     *intern;
  spl_ptr_llist_element *element;
  zend_long                  index;

  if (zend_parse_parameters(ZEND_NUM_ARGS(), "lz", &index, &value) == FAILURE) {
    RETURN_THROWS();
  }

  intern = Z_SPLDLLIST_P(ZEND_THIS);

  if (index < 0 || index > intern->llist->count) {
    zend_argument_error(spl_ce_OutOfRangeException, 1, "is out of range");
    RETURN_THROWS();
  }

  if (index == intern->llist->count) {
    /* If index is the last entry+1 then we do a push because we're not inserting before any entry */
    spl_ptr_llist_push(intern->llist, value);
  } else {
    /* Create the new element we want to insert */
    spl_ptr_llist_element *elem = emalloc(sizeof(spl_ptr_llist_element));

    /* Get the element we want to insert before */
    element = spl_ptr_llist_offset(intern->llist, index, intern->flags & SPL_DLLIST_IT_LIFO);
    ZEND_ASSERT(element != NULL);

    ZVAL_COPY(&elem->data, value);
    SPL_LLIST_RC(elem) = 1;
    /* connect to the neighbours */
    elem->next = element;
    elem->prev = element->prev;

    /* connect the neighbours to this new element */
    if (elem->prev == NULL) {
      intern->llist->head = elem;
    } else {
      element->prev->next = elem;
    }
    element->prev = elem;

    intern->llist->count++;
  }
} /* }}} */

/* {{{ */
PHP_METHOD(SplDoublyLinkedList, __debugInfo)
{
  ZEND_PARSE_PARAMETERS_NONE();

  RETURN_ARR(spl_dllist_object_get_debug_info(Z_OBJ_P(ZEND_THIS)));
} /* }}} */

/* {{{ iterator handler table */
static const zend_object_iterator_funcs spl_dllist_it_funcs = {
  spl_dllist_it_dtor,
  spl_dllist_it_valid,
  spl_dllist_it_get_current_data,
  spl_dllist_it_get_current_key,
  spl_dllist_it_move_forward,
  spl_dllist_it_rewind,
  NULL,
  NULL, /* get_gc */
}; /* }}} */

static zend_object_iterator *spl_dllist_get_iterator(zend_class_entry *ce, zval *object, int by_ref) /* {{{ */
{
  spl_dllist_object *dllist_object = Z_SPLDLLIST_P(object);

  if (by_ref) {
    zend_throw_error(NULL, "An iterator cannot be used with foreach by reference");
    return NULL;
  }

  spl_dllist_it *iterator = emalloc(sizeof(spl_dllist_it));

  zend_iterator_init(&iterator->intern);

  ZVAL_OBJ_COPY(&iterator->intern.data, Z_OBJ_P(object));
  iterator->intern.funcs       = &spl_dllist_it_funcs;
  iterator->traverse_position  = dllist_object->traverse_position;
  iterator->traverse_pointer   = dllist_object->traverse_pointer;
  iterator->flags              = dllist_object->flags & SPL_DLLIST_IT_MASK;

  SPL_LLIST_CHECK_ADDREF(iterator->traverse_pointer);

  return &iterator->intern;
}
/* }}} */

PHP_MINIT_FUNCTION(spl_dllist) /* {{{ */
{
  spl_ce_SplDoublyLinkedList = register_class_SplDoublyLinkedList(
    zend_ce_iterator, zend_ce_countable, zend_ce_arrayaccess, zend_ce_serializable
  );
  spl_ce_SplDoublyLinkedList->create_object = spl_dllist_object_new;
  spl_ce_SplDoublyLinkedList->default_object_handlers = &spl_handler_SplDoublyLinkedList;
  spl_ce_SplDoublyLinkedList->get_iterator = spl_dllist_get_iterator;

  memcpy(&spl_handler_SplDoublyLinkedList, &std_object_handlers, sizeof(zend_object_handlers));

  spl_handler_SplDoublyLinkedList.offset = offsetof(spl_dllist_object, std);
  spl_handler_SplDoublyLinkedList.clone_obj = spl_dllist_object_clone;
  spl_handler_SplDoublyLinkedList.count_elements = spl_dllist_object_count_elements;
  spl_handler_SplDoublyLinkedList.get_gc = spl_dllist_object_get_gc;
  spl_handler_SplDoublyLinkedList.free_obj = spl_dllist_object_free_storage;

  spl_ce_SplQueue = register_class_SplQueue(spl_ce_SplDoublyLinkedList);
  spl_ce_SplQueue->create_object = spl_dllist_object_new;
  spl_ce_SplQueue->get_iterator = spl_dllist_get_iterator;

  spl_ce_SplStack = register_class_SplStack(spl_ce_SplDoublyLinkedList);
  spl_ce_SplStack->create_object = spl_dllist_object_new;
  spl_ce_SplStack->get_iterator = spl_dllist_get_iterator;

  return SUCCESS;
}
/* }}} */

Coverage Report

Created: 2026-06-02 06:40