/src/php-src/ext/spl/spl_heap.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 "spl_heap.h"
#include "spl_heap_arginfo.h"
#include "spl_exceptions.h"
#include "spl_functions.h" /* For spl_set_private_debug_info_property() */

#define PTR_HEAP_BLOCK_SIZE 64

#define SPL_HEAP_CORRUPTED       0x00000001
#define SPL_HEAP_WRITE_LOCKED    0x00000002

static zend_object_handlers spl_handler_SplHeap;
static zend_object_handlers spl_handler_SplPriorityQueue;

PHPAPI zend_class_entry  *spl_ce_SplHeap;
PHPAPI zend_class_entry  *spl_ce_SplMaxHeap;
PHPAPI zend_class_entry  *spl_ce_SplMinHeap;
PHPAPI zend_class_entry  *spl_ce_SplPriorityQueue;


typedef void (*spl_ptr_heap_dtor_func)(void *);
typedef void (*spl_ptr_heap_ctor_func)(void *);
typedef int  (*spl_ptr_heap_cmp_func)(void *, void *, zval *);

typedef struct _spl_ptr_heap {
  void                   *elements;
  spl_ptr_heap_ctor_func  ctor;
  spl_ptr_heap_dtor_func  dtor;
  spl_ptr_heap_cmp_func   cmp;
  size_t                  count;
  int                     flags;
  size_t                  max_size;
  size_t                  elem_size;
} spl_ptr_heap;

typedef struct _spl_heap_object spl_heap_object;
typedef struct _spl_heap_it spl_heap_it;

struct _spl_heap_object {
  spl_ptr_heap       *heap;
  int                 flags;
  zend_function      *fptr_cmp;
  zend_function      *fptr_count;
  zend_object         std;
};

typedef struct _spl_pqueue_elem {
  zval data;
  zval priority;
} spl_pqueue_elem;

#define spl_heap_from_obj(obj) ZEND_CONTAINER_OF(obj, spl_heap_object, std)

#define Z_SPLHEAP_P(zv)  spl_heap_from_obj(Z_OBJ_P((zv)))

static zend_always_inline void *spl_heap_elem(spl_ptr_heap *heap, size_t i) {
  return (void *) ((char *) heap->elements + heap->elem_size * i);
}

static zend_always_inline void spl_heap_elem_copy(spl_ptr_heap *heap, void *to, void *from) {
  assert(to != from);

  /* Specialized for cases of heap and priority queue. With the size being
   * constant known at compile time the compiler can fully inline calls to memcpy. */
  if (heap->elem_size == sizeof(spl_pqueue_elem)) {
    memcpy(to, from, sizeof(spl_pqueue_elem));
  } else {
    ZEND_ASSERT(heap->elem_size == sizeof(zval));
    memcpy(to, from, sizeof(zval));
  }
}

static void spl_ptr_heap_zval_dtor(void *elem) { /* {{{ */
  zval_ptr_dtor((zval *) elem);
}
/* }}} */

static void spl_ptr_heap_zval_ctor(void *elem) { /* {{{ */
  Z_TRY_ADDREF_P((zval *) elem);
}
/* }}} */

static void spl_ptr_heap_pqueue_elem_dtor(void *elem) { /* {{{ */
  spl_pqueue_elem *pq_elem = elem;
  zval_ptr_dtor(&pq_elem->data);
  zval_ptr_dtor(&pq_elem->priority);
}
/* }}} */

static void spl_ptr_heap_pqueue_elem_ctor(void *elem) { /* {{{ */
  spl_pqueue_elem *pq_elem = elem;
  Z_TRY_ADDREF_P(&pq_elem->data);
  Z_TRY_ADDREF_P(&pq_elem->priority);
}
/* }}} */

static zend_result spl_ptr_heap_cmp_cb_helper(zval *object, spl_heap_object *heap_object, zval *a, zval *b, zend_long *result) { /* {{{ */
  zval zresult;

  zend_call_method_with_2_params(Z_OBJ_P(object), heap_object->std.ce, &heap_object->fptr_cmp, "compare", &zresult, a, b);

  if (EG(exception)) {
    return FAILURE;
  }

  *result = zval_get_long(&zresult);
  zval_ptr_dtor(&zresult);

  return SUCCESS;
}
/* }}} */

static void spl_pqueue_extract_helper(zval *result, spl_pqueue_elem *elem, int flags) /* {{{ */
{
  if ((flags & SPL_PQUEUE_EXTR_BOTH) == SPL_PQUEUE_EXTR_BOTH) {
    array_init(result);
    Z_TRY_ADDREF(elem->data);
    add_assoc_zval_ex(result, "data", sizeof("data") - 1, &elem->data);
    Z_TRY_ADDREF(elem->priority);
    add_assoc_zval_ex(result, "priority", sizeof("priority") - 1, &elem->priority);
    return;
  }

  if (flags & SPL_PQUEUE_EXTR_DATA) {
    ZVAL_COPY(result, &elem->data);
    return;
  }

  if (flags & SPL_PQUEUE_EXTR_PRIORITY) {
    ZVAL_COPY(result, &elem->priority);
    return;
  }

  ZEND_UNREACHABLE();
}
/* }}} */

static int spl_ptr_heap_zval_max_cmp(void *x, void *y, zval *object) { /* {{{ */
  zval *a = x, *b = y;

  if (EG(exception)) {
    return 0;
  }

  if (object) {
    spl_heap_object *heap_object = Z_SPLHEAP_P(object);
    if (heap_object->fptr_cmp) {
      zend_long lval = 0;
      if (spl_ptr_heap_cmp_cb_helper(object, heap_object, a, b, &lval) == FAILURE) {
        /* exception or call failure */
        return 0;
      }
      return ZEND_NORMALIZE_BOOL(lval);
    }
  }

  return zend_compare(a, b);
}
/* }}} */

static int spl_ptr_heap_zval_min_cmp(void *x, void *y, zval *object) { /* {{{ */
  zval *a = x, *b = y;

  if (EG(exception)) {
    return 0;
  }

  if (object) {
    spl_heap_object *heap_object = Z_SPLHEAP_P(object);
    if (heap_object->fptr_cmp) {
      zend_long lval = 0;
      if (spl_ptr_heap_cmp_cb_helper(object, heap_object, a, b, &lval) == FAILURE) {
        /* exception or call failure */
        return 0;
      }
      return ZEND_NORMALIZE_BOOL(lval);
    }
  }

  return zend_compare(b, a);
}
/* }}} */

static int spl_ptr_pqueue_elem_cmp(void *x, void *y, zval *object) { /* {{{ */
  spl_pqueue_elem *a = x;
  spl_pqueue_elem *b = y;
  zval *a_priority_p = &a->priority;
  zval *b_priority_p = &b->priority;

  if (EG(exception)) {
    return 0;
  }

  if (object) {
    spl_heap_object *heap_object = Z_SPLHEAP_P(object);
    if (heap_object->fptr_cmp) {
      zend_long lval = 0;
      if (spl_ptr_heap_cmp_cb_helper(object, heap_object, a_priority_p, b_priority_p, &lval) == FAILURE) {
        /* exception or call failure */
        return 0;
      }
      return ZEND_NORMALIZE_BOOL(lval);
    }
  }

  return zend_compare(a_priority_p, b_priority_p);
}
/* }}} */

/* Specialized comparator used when we are absolutely sure an instance of the
 * not inherited SplPriorityQueue class contains only priorities as longs. This
 * fact is tracked during insertion into the queue. */
static int spl_ptr_pqueue_elem_cmp_long(void *x, void *y, zval *object) {
  zend_long a = Z_LVAL(((spl_pqueue_elem*) x)->priority);
  zend_long b = Z_LVAL(((spl_pqueue_elem*) y)->priority);
  return a>b ? 1 : (a<b ? -1 : 0);
}

/* same as spl_ptr_pqueue_elem_cmp_long */
static int spl_ptr_pqueue_elem_cmp_double(void *x, void *y, zval *object) {
  double a = Z_DVAL(((spl_pqueue_elem*) x)->priority);
  double b = Z_DVAL(((spl_pqueue_elem*) y)->priority);
  return ZEND_THREEWAY_COMPARE(a, b);
}

static spl_ptr_heap *spl_ptr_heap_init(spl_ptr_heap_cmp_func cmp, spl_ptr_heap_ctor_func ctor, spl_ptr_heap_dtor_func dtor, size_t elem_size) /* {{{ */
{
  spl_ptr_heap *heap = emalloc(sizeof(spl_ptr_heap));

  heap->dtor     = dtor;
  heap->ctor     = ctor;
  heap->cmp      = cmp;
  heap->elements = ecalloc(PTR_HEAP_BLOCK_SIZE, elem_size);
  heap->max_size = PTR_HEAP_BLOCK_SIZE;
  heap->count    = 0;
  heap->flags    = 0;
  heap->elem_size = elem_size;

  return heap;
}
/* }}} */

static void spl_ptr_heap_insert(spl_ptr_heap *heap, void *elem, void *cmp_userdata) { /* {{{ */
  if (heap->count+1 > heap->max_size) {
    size_t alloc_size = heap->max_size * heap->elem_size;
    /* we need to allocate more memory */
    heap->elements  = safe_erealloc(heap->elements, 2, alloc_size, 0);
    memset((char *) heap->elements + alloc_size, 0, alloc_size);
    heap->max_size *= 2;
  }

  heap->flags |= SPL_HEAP_WRITE_LOCKED;

  /* sifting up */
  size_t pos;
  for (pos = heap->count; pos > 0 && heap->cmp(spl_heap_elem(heap, (pos-1)/2), elem, cmp_userdata) < 0; pos = (pos-1)/2) {
    spl_heap_elem_copy(heap, spl_heap_elem(heap, pos), spl_heap_elem(heap, (pos-1)/2));
  }
  heap->count++;

  heap->flags &= ~SPL_HEAP_WRITE_LOCKED;

  if (EG(exception)) {
    /* exception thrown during comparison */
    heap->flags |= SPL_HEAP_CORRUPTED;
  }

  spl_heap_elem_copy(heap, spl_heap_elem(heap, pos), elem);
}
/* }}} */

static void *spl_ptr_heap_top(spl_ptr_heap *heap) { /* {{{ */
  if (heap->count == 0) {
    return NULL;
  }

  return heap->elements;
}
/* }}} */

static zend_result spl_ptr_heap_delete_top(spl_ptr_heap *heap, void *elem, void *cmp_userdata) { /* {{{ */
  const size_t limit = (heap->count-1)/2;
  void *bottom;

  if (heap->count == 0) {
    return FAILURE;
  }

  heap->flags |= SPL_HEAP_WRITE_LOCKED;

  if (elem) {
    spl_heap_elem_copy(heap, elem, spl_heap_elem(heap, 0));
  } else {
    heap->dtor(spl_heap_elem(heap, 0));
  }

  bottom = spl_heap_elem(heap, --heap->count);

  size_t parent_idx, child_idx;
  for (parent_idx = 0; parent_idx < limit; parent_idx = child_idx) {
    /* Find smaller child */
    child_idx = parent_idx * 2 + 1;
    if (child_idx != heap->count && heap->cmp(spl_heap_elem(heap, child_idx+1), spl_heap_elem(heap, child_idx), cmp_userdata) > 0) {
      child_idx++; /* next child is bigger */
    }

    /* swap elements between two levels */
    if(heap->cmp(bottom, spl_heap_elem(heap, child_idx), cmp_userdata) < 0) {
      spl_heap_elem_copy(heap, spl_heap_elem(heap, parent_idx), spl_heap_elem(heap, child_idx));
    } else {
      break;
    }
  }

  heap->flags &= ~SPL_HEAP_WRITE_LOCKED;

  if (EG(exception)) {
    /* exception thrown during comparison */
    heap->flags |= SPL_HEAP_CORRUPTED;
  }

  void *to = spl_heap_elem(heap, parent_idx);
  if (to != bottom) {
    spl_heap_elem_copy(heap, to, bottom);
  }
  return SUCCESS;
}
/* }}} */

static spl_ptr_heap *spl_ptr_heap_clone(spl_ptr_heap *from) { /* {{{ */
  spl_ptr_heap *heap = emalloc(sizeof(spl_ptr_heap));

  heap->dtor     = from->dtor;
  heap->ctor     = from->ctor;
  heap->cmp      = from->cmp;
  heap->max_size = from->max_size;
  heap->count    = from->count;
  heap->flags    = from->flags;
  heap->elem_size = from->elem_size;

  heap->elements = safe_emalloc(from->elem_size, from->max_size, 0);
  memcpy(heap->elements, from->elements, from->elem_size * from->max_size);

  for (size_t i = 0; i < heap->count; ++i) {
    heap->ctor(spl_heap_elem(heap, i));
  }

  return heap;
}
/* }}} */

static void spl_ptr_heap_destroy(spl_ptr_heap *heap) { /* {{{ */
  /* Heap might be null if we OOMed during object initialization. */
  if (!heap) {
    return;
  }

  heap->flags |= SPL_HEAP_WRITE_LOCKED;

  for (size_t i = 0; i < heap->count; ++i) {
    heap->dtor(spl_heap_elem(heap, i));
  }

  heap->flags &= ~SPL_HEAP_WRITE_LOCKED;

  efree(heap->elements);
  efree(heap);
}
/* }}} */

static size_t spl_ptr_heap_count(spl_ptr_heap *heap) { /* {{{ */
  return heap->count;
}
/* }}} */

static void spl_heap_object_free_storage(zend_object *object) /* {{{ */
{
  spl_heap_object *intern = spl_heap_from_obj(object);

  zend_object_std_dtor(&intern->std);

  spl_ptr_heap_destroy(intern->heap);
}
/* }}} */

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

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

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

  if (orig) {
    spl_heap_object *other = spl_heap_from_obj(orig);
    intern->std.handlers = other->std.handlers;

    if (clone_orig) {
      intern->heap = spl_ptr_heap_clone(other->heap);
    } else {
      intern->heap = other->heap;
    }

    intern->flags = other->flags;
    intern->fptr_cmp = other->fptr_cmp;
    intern->fptr_count = other->fptr_count;
    return &intern->std;
  }

  while (parent) {
    if (parent == spl_ce_SplPriorityQueue) {
      intern->heap = spl_ptr_heap_init(spl_ptr_pqueue_elem_cmp, spl_ptr_heap_pqueue_elem_ctor, spl_ptr_heap_pqueue_elem_dtor, sizeof(spl_pqueue_elem));
      intern->flags = SPL_PQUEUE_EXTR_DATA;
      break;
    }

    if (parent == spl_ce_SplMinHeap || parent == spl_ce_SplMaxHeap
        || parent == spl_ce_SplHeap) {
      intern->heap = spl_ptr_heap_init(
        parent == spl_ce_SplMinHeap ? spl_ptr_heap_zval_min_cmp : spl_ptr_heap_zval_max_cmp,
        spl_ptr_heap_zval_ctor, spl_ptr_heap_zval_dtor, sizeof(zval));
      break;
    }

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

  ZEND_ASSERT(parent);

  if (inherited) {
    intern->fptr_cmp = zend_hash_str_find_ptr(&class_type->function_table, "compare", sizeof("compare") - 1);
    if (intern->fptr_cmp->common.scope == parent) {
      intern->fptr_cmp = NULL;
    }
    /* 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_heap_object_new(zend_class_entry *class_type) /* {{{ */
{
  return spl_heap_object_new_ex(class_type, NULL, 0);
}
/* }}} */

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

  zend_objects_clone_members(new_object, old_object);

  return new_object;
}
/* }}} */

static zend_result spl_heap_object_count_elements(zend_object *object, zend_long *count) /* {{{ */
{
  spl_heap_object *intern = spl_heap_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_heap_count(intern->heap);

  return SUCCESS;
}
/* }}} */

static HashTable* spl_heap_object_get_debug_info(const zend_class_entry *ce, zend_object *obj) { /* {{{ */
  spl_heap_object *intern = spl_heap_from_obj(obj);
  zval tmp, heap_array;
  HashTable *debug_info;
  HashTable *properties = zend_std_get_properties_ex(&intern->std);

  /* +3 As we are adding 3 additional key-entries */
  debug_info = zend_new_array(zend_hash_num_elements(properties) + 3);
  zend_hash_copy(debug_info, properties, (copy_ctor_func_t) zval_add_ref);

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

  ZVAL_BOOL(&tmp, intern->heap->flags&SPL_HEAP_CORRUPTED);
  spl_set_private_debug_info_property(ce, "isCorrupted", strlen("isCorrupted"), debug_info, &tmp);

  array_init(&heap_array);

  for (size_t i = 0; i < intern->heap->count; ++i) {
    if (ce == spl_ce_SplPriorityQueue) {
      spl_pqueue_elem *pq_elem = spl_heap_elem(intern->heap, i);
      zval elem;
      spl_pqueue_extract_helper(&elem, pq_elem, SPL_PQUEUE_EXTR_BOTH);
      add_index_zval(&heap_array, i, &elem);
    } else {
      zval *elem = spl_heap_elem(intern->heap, i);
      add_index_zval(&heap_array, i, elem);
      Z_TRY_ADDREF_P(elem);
    }
  }

  spl_set_private_debug_info_property(ce, "heap", strlen("heap"), debug_info, &heap_array);

  return debug_info;
}
/* }}} */

static HashTable *spl_heap_object_get_gc(zend_object *obj, zval **gc_data, int *gc_data_count) /* {{{ */
{
  spl_heap_object *intern = spl_heap_from_obj(obj);
  *gc_data = (zval *) intern->heap->elements;
  *gc_data_count = intern->heap->count;

  return zend_std_get_properties(obj);
}
/* }}} */

static HashTable *spl_pqueue_object_get_gc(zend_object *obj, zval **gc_data, int *gc_data_count) /* {{{ */
{
  spl_heap_object *intern = spl_heap_from_obj(obj);
  *gc_data = (zval *) intern->heap->elements;
  /* Two zvals (value and priority) per pqueue entry */
  *gc_data_count = 2 * intern->heap->count;

  return zend_std_get_properties(obj);
}
/* }}} */

/* {{{ Return the number of elements in the heap. */
PHP_METHOD(SplHeap, count)
{
  zend_long count;
  spl_heap_object *intern = Z_SPLHEAP_P(ZEND_THIS);

  ZEND_PARSE_PARAMETERS_NONE();

  count = spl_ptr_heap_count(intern->heap);
  RETURN_LONG(count);
}
/* }}} */

/* {{{ Return true if the heap is empty. */
PHP_METHOD(SplHeap, isEmpty)
{
  spl_heap_object *intern = Z_SPLHEAP_P(ZEND_THIS);

  ZEND_PARSE_PARAMETERS_NONE();

  RETURN_BOOL(spl_ptr_heap_count(intern->heap) == 0);
}
/* }}} */

static zend_result spl_heap_consistency_validations(const spl_heap_object *intern, bool write)
{
  if (intern->heap->flags & SPL_HEAP_CORRUPTED) {
    zend_throw_exception(spl_ce_RuntimeException, "Heap is corrupted, heap properties are no longer ensured.", 0);
    return FAILURE;
  }

  if (write && (intern->heap->flags & SPL_HEAP_WRITE_LOCKED)) {
    zend_throw_exception(spl_ce_RuntimeException, "Heap cannot be changed when it is already being modified.", 0);
    return FAILURE;
  }

  return SUCCESS;
}

/* {{{ Push $value on the heap */
PHP_METHOD(SplHeap, insert)
{
  zval *value;
  spl_heap_object *intern;

  ZEND_PARSE_PARAMETERS_START(1, 1)
    Z_PARAM_ZVAL(value);
  ZEND_PARSE_PARAMETERS_END();

  intern = Z_SPLHEAP_P(ZEND_THIS);

  if (UNEXPECTED(spl_heap_consistency_validations(intern, true) != SUCCESS)) {
    RETURN_THROWS();
  }

  Z_TRY_ADDREF_P(value);
  spl_ptr_heap_insert(intern->heap, value, ZEND_THIS);

  RETURN_TRUE;
}
/* }}} */

/* {{{ extract the element out of the top of the heap */
PHP_METHOD(SplHeap, extract)
{
  spl_heap_object *intern;

  ZEND_PARSE_PARAMETERS_NONE();

  intern = Z_SPLHEAP_P(ZEND_THIS);

  if (UNEXPECTED(spl_heap_consistency_validations(intern, true) != SUCCESS)) {
    RETURN_THROWS();
  }

  if (spl_ptr_heap_delete_top(intern->heap, return_value, ZEND_THIS) == FAILURE) {
    zend_throw_exception(spl_ce_RuntimeException, "Can't extract from an empty heap", 0);
    RETURN_THROWS();
  }
}
/* }}} */

/* {{{ Push $value with the priority $priodiry on the priorityqueue */
PHP_METHOD(SplPriorityQueue, insert)
{
  zval *data, *priority;
  spl_heap_object *intern;
  spl_pqueue_elem elem;

  ZEND_PARSE_PARAMETERS_START(2, 2)
    Z_PARAM_ZVAL(data);
    Z_PARAM_ZVAL(priority);
  ZEND_PARSE_PARAMETERS_END();

  intern = Z_SPLHEAP_P(ZEND_THIS);

  if (UNEXPECTED(spl_heap_consistency_validations(intern, true) != SUCCESS)) {
    RETURN_THROWS();
  }

  ZVAL_COPY(&elem.data, data);
  ZVAL_COPY(&elem.priority, priority);

  /* If we know this call came from non inherited SplPriorityQueue it's
   * possible to do specialization on the type of the priority parameter. */
  if (!intern->fptr_cmp) {
    int type = Z_TYPE(elem.priority);
    spl_ptr_heap_cmp_func new_cmp =
      (type == IS_LONG) ? spl_ptr_pqueue_elem_cmp_long :
      ((type == IS_DOUBLE) ? spl_ptr_pqueue_elem_cmp_double : spl_ptr_pqueue_elem_cmp);

    if (intern->heap->count == 0) { /* Specialize empty queue */
      intern->heap->cmp = new_cmp;
    } else if (new_cmp != intern->heap->cmp) { /* Despecialize on type conflict. */
      intern->heap->cmp = spl_ptr_pqueue_elem_cmp;
    }
  }

  spl_ptr_heap_insert(intern->heap, &elem, ZEND_THIS);

  RETURN_TRUE;
}
/* }}} */

/* {{{ extract the element out of the top of the priority queue */
PHP_METHOD(SplPriorityQueue, extract)
{
  spl_pqueue_elem elem;
  spl_heap_object *intern;

  ZEND_PARSE_PARAMETERS_NONE();

  intern = Z_SPLHEAP_P(ZEND_THIS);

  if (UNEXPECTED(spl_heap_consistency_validations(intern, true) != SUCCESS)) {
    RETURN_THROWS();
  }

  if (spl_ptr_heap_delete_top(intern->heap, &elem, ZEND_THIS) == FAILURE) {
    zend_throw_exception(spl_ce_RuntimeException, "Can't extract from an empty heap", 0);
    RETURN_THROWS();
  }

  spl_pqueue_extract_helper(return_value, &elem, intern->flags);
  spl_ptr_heap_pqueue_elem_dtor(&elem);
}
/* }}} */

/* {{{ Peek at the top element of the priority queue */
PHP_METHOD(SplPriorityQueue, top)
{
  spl_heap_object *intern;
  spl_pqueue_elem *elem;

  ZEND_PARSE_PARAMETERS_NONE();

  intern = Z_SPLHEAP_P(ZEND_THIS);

  if (UNEXPECTED(spl_heap_consistency_validations(intern, false) != SUCCESS)) {
    RETURN_THROWS();
  }

  elem = spl_ptr_heap_top(intern->heap);

  if (!elem) {
    zend_throw_exception(spl_ce_RuntimeException, "Can't peek at an empty heap", 0);
    RETURN_THROWS();
  }

  spl_pqueue_extract_helper(return_value, elem, intern->flags);
}
/* }}} */


/* {{{ Set the flags of extraction*/
PHP_METHOD(SplPriorityQueue, setExtractFlags)
{
  zend_long value;
  spl_heap_object *intern;

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

  value &= SPL_PQUEUE_EXTR_MASK;
  if (!value) {
    zend_throw_exception(spl_ce_RuntimeException, "Must specify at least one extract flag", 0);
    RETURN_THROWS();
  }

  intern = Z_SPLHEAP_P(ZEND_THIS);
  intern->flags = value;
  RETURN_LONG(intern->flags);
}
/* }}} */

/* {{{ Get the flags of extraction*/
PHP_METHOD(SplPriorityQueue, getExtractFlags)
{
  spl_heap_object *intern;

  ZEND_PARSE_PARAMETERS_NONE();

  intern = Z_SPLHEAP_P(ZEND_THIS);

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

/* {{{ Recover from a corrupted state*/
PHP_METHOD(SplHeap, recoverFromCorruption)
{
  spl_heap_object *intern;

  ZEND_PARSE_PARAMETERS_NONE();

  intern = Z_SPLHEAP_P(ZEND_THIS);

  intern->heap->flags = intern->heap->flags & ~SPL_HEAP_CORRUPTED;

  RETURN_TRUE;
}
/* }}} */

/* {{{ Tells if the heap is in a corrupted state*/
PHP_METHOD(SplHeap, isCorrupted)
{
  spl_heap_object *intern;

  ZEND_PARSE_PARAMETERS_NONE();

  intern = Z_SPLHEAP_P(ZEND_THIS);

  RETURN_BOOL(intern->heap->flags & SPL_HEAP_CORRUPTED);
}
/* }}} */

/* {{{ compare the priorities */
PHP_METHOD(SplPriorityQueue, compare)
{
  zval *a, *b;

  if (zend_parse_parameters(ZEND_NUM_ARGS(), "zz", &a, &b) == FAILURE) {
    RETURN_THROWS();
  }

  RETURN_LONG(spl_ptr_heap_zval_max_cmp(a, b, NULL));
}
/* }}} */

/* {{{ Peek at the top element of the heap */
PHP_METHOD(SplHeap, top)
{
  zval *value;
  spl_heap_object *intern;

  ZEND_PARSE_PARAMETERS_NONE();

  intern = Z_SPLHEAP_P(ZEND_THIS);

  if (UNEXPECTED(spl_heap_consistency_validations(intern, false) != SUCCESS)) {
    RETURN_THROWS();
  }

  value = spl_ptr_heap_top(intern->heap);

  if (!value) {
    zend_throw_exception(spl_ce_RuntimeException, "Can't peek at an empty heap", 0);
    RETURN_THROWS();
  }

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

/* {{{ compare the values */
PHP_METHOD(SplMinHeap, compare)
{
  zval *a, *b;

  if (zend_parse_parameters(ZEND_NUM_ARGS(), "zz", &a, &b) == FAILURE) {
    RETURN_THROWS();
  }

  RETURN_LONG(spl_ptr_heap_zval_min_cmp(a, b, NULL));
}
/* }}} */

/* {{{ compare the values */
PHP_METHOD(SplMaxHeap, compare)
{
  zval *a, *b;

  if (zend_parse_parameters(ZEND_NUM_ARGS(), "zz", &a, &b) == FAILURE) {
    RETURN_THROWS();
  }

  RETURN_LONG(spl_ptr_heap_zval_max_cmp(a, b, NULL));
}
/* }}} */

static void spl_heap_it_dtor(zend_object_iterator *iter) /* {{{ */
{
  zend_user_it_invalidate_current(iter);
  zval_ptr_dtor(&iter->data);
}
/* }}} */

static void spl_heap_it_rewind(zend_object_iterator *iter) /* {{{ */
{
  /* do nothing, the iterator always points to the top element */
}
/* }}} */

static zend_result spl_heap_it_valid(zend_object_iterator *iter) /* {{{ */
{
  return ((Z_SPLHEAP_P(&iter->data))->heap->count != 0 ? SUCCESS : FAILURE);
}
/* }}} */

static zval *spl_heap_it_get_current_data(zend_object_iterator *iter) /* {{{ */
{
  spl_heap_object *object = Z_SPLHEAP_P(&iter->data);

  if (UNEXPECTED(spl_heap_consistency_validations(object, false) != SUCCESS)) {
    return NULL;
  }

  if (object->heap->count == 0) {
    return NULL;
  } else {
    return spl_heap_elem(object->heap, 0);
  }
}
/* }}} */

static zval *spl_pqueue_it_get_current_data(zend_object_iterator *iter) /* {{{ */
{
  zend_user_iterator *user_it = (zend_user_iterator *) iter;
  spl_heap_object *object = Z_SPLHEAP_P(&iter->data);

  if (UNEXPECTED(spl_heap_consistency_validations(object, false) != SUCCESS)) {
    return NULL;
  }

  if (object->heap->count == 0) {
    return NULL;
  }

  if (Z_ISUNDEF(user_it->value)) {
    spl_pqueue_elem *elem = spl_heap_elem(object->heap, 0);
    spl_pqueue_extract_helper(&user_it->value, elem, object->flags);
  }
  return &user_it->value;
}
/* }}} */

static void spl_heap_it_get_current_key(zend_object_iterator *iter, zval *key) /* {{{ */
{
  spl_heap_object *object = Z_SPLHEAP_P(&iter->data);

  ZVAL_LONG(key, object->heap->count - 1);
}
/* }}} */

static void spl_heap_it_move_forward(zend_object_iterator *iter) /* {{{ */
{
  spl_heap_object *object = Z_SPLHEAP_P(&iter->data);

  if (UNEXPECTED(spl_heap_consistency_validations(object, true) != SUCCESS)) {
    return;
  }

  spl_ptr_heap_delete_top(object->heap, NULL, &iter->data);
  zend_user_it_invalidate_current(iter);
}
/* }}} */

/* {{{ Return current array key */
PHP_METHOD(SplHeap, key)
{
  spl_heap_object *intern = Z_SPLHEAP_P(ZEND_THIS);

  ZEND_PARSE_PARAMETERS_NONE();

  RETURN_LONG(intern->heap->count - 1);
}
/* }}} */

/* {{{ Move to next entry */
PHP_METHOD(SplHeap, next)
{
  spl_heap_object *intern = Z_SPLHEAP_P(ZEND_THIS);

  ZEND_PARSE_PARAMETERS_NONE();

  if (UNEXPECTED(spl_heap_consistency_validations(intern, true) != SUCCESS)) {
    RETURN_THROWS();
  }

  spl_ptr_heap_delete_top(intern->heap, NULL, ZEND_THIS);
}
/* }}} */

/* {{{ Check whether the datastructure contains more entries */
PHP_METHOD(SplHeap, valid)
{
  spl_heap_object *intern = Z_SPLHEAP_P(ZEND_THIS);

  ZEND_PARSE_PARAMETERS_NONE();

  RETURN_BOOL(intern->heap->count != 0);
}
/* }}} */

/* {{{ Rewind the datastructure back to the start */
PHP_METHOD(SplHeap, rewind)
{
  ZEND_PARSE_PARAMETERS_NONE();
  /* do nothing, the iterator always points to the top element */
}
/* }}} */

/* {{{ Return current datastructure entry */
PHP_METHOD(SplHeap, current)
{
  spl_heap_object *intern  = Z_SPLHEAP_P(ZEND_THIS);

  ZEND_PARSE_PARAMETERS_NONE();

  if (!intern->heap->count) {
    RETURN_NULL();
  } else {
    zval *element = spl_heap_elem(intern->heap, 0);
    RETURN_COPY_DEREF(element);
  }
}
/* }}} */

/* {{{ Return current datastructure entry */
PHP_METHOD(SplPriorityQueue, current)
{
  spl_heap_object  *intern  = Z_SPLHEAP_P(ZEND_THIS);

  ZEND_PARSE_PARAMETERS_NONE();

  if (!intern->heap->count) {
    RETURN_NULL();
  } else {
    spl_pqueue_elem *elem = spl_heap_elem(intern->heap, 0);
    spl_pqueue_extract_helper(return_value, elem, intern->flags);
  }
}
/* }}} */

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

  RETURN_ARR(spl_heap_object_get_debug_info(spl_ce_SplHeap, Z_OBJ_P(ZEND_THIS)));
} /* }}} */

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

  RETURN_ARR(spl_heap_object_get_debug_info(spl_ce_SplPriorityQueue, Z_OBJ_P(ZEND_THIS)));
} /* }}} */

static void spl_heap_serialize_internal_state(zval *return_value, spl_heap_object *intern, bool is_pqueue)
{
  zval heap_elements;
  int heap_count = intern->heap->count;

  array_init(return_value);
  add_assoc_long(return_value, "flags", intern->flags);

  array_init_size(&heap_elements, heap_count);

  if (heap_count == 0) {
    add_assoc_zval(return_value, "heap_elements", &heap_elements);
    return;
  }

  for (int heap_idx = 0; heap_idx < heap_count; ++heap_idx) {
    if (is_pqueue) {
      spl_pqueue_elem *elem = spl_heap_elem(intern->heap, heap_idx);
      zval entry;
      array_init(&entry);
      add_assoc_zval_ex(&entry, "data", strlen("data"), &elem->data);
      Z_TRY_ADDREF(elem->data);
      add_assoc_zval_ex(&entry, "priority", strlen("priority"), &elem->priority);
      Z_TRY_ADDREF(elem->priority);
      zend_hash_next_index_insert(Z_ARRVAL(heap_elements), &entry);
    } else {
      zval *elem = spl_heap_elem(intern->heap, heap_idx);
      zend_hash_next_index_insert(Z_ARRVAL(heap_elements), elem);
      Z_TRY_ADDREF_P(elem);
    }
  }

  add_assoc_zval(return_value, "heap_elements", &heap_elements);
}

static zend_result spl_heap_unserialize_internal_state(HashTable *state_ht, spl_heap_object *intern, zval *this_ptr, bool is_pqueue)
{
  zval *flags_val = zend_hash_str_find(state_ht, "flags", strlen("flags"));
  if (!flags_val || Z_TYPE_P(flags_val) != IS_LONG) {
    return FAILURE;
  }

  zend_long flags_value = Z_LVAL_P(flags_val);

  if (is_pqueue) {
    flags_value &= SPL_PQUEUE_EXTR_MASK;
    if (!flags_value) {
      return FAILURE;
    }
  } else if (flags_value != 0) { /* Regular heaps should not have user-visible flags */
    return FAILURE;
  }

  intern->flags = (int) flags_value;

  zval *heap_elements = zend_hash_str_find(state_ht, "heap_elements", strlen("heap_elements"));
  if (!heap_elements) {
    return FAILURE;
  }

  if (Z_TYPE_P(heap_elements) != IS_ARRAY) {
    return FAILURE;
  }

  ZEND_HASH_FOREACH_VAL(Z_ARRVAL_P(heap_elements), zval *val) {
    if (is_pqueue) {
      /* PriorityQueue elements are serialized as arrays with 'data' and 'priority' keys */
      if (Z_TYPE_P(val) != IS_ARRAY || zend_hash_num_elements(Z_ARRVAL_P(val)) != 2) {
        return FAILURE;
      }

      zval *data_val = zend_hash_str_find(Z_ARRVAL_P(val), "data", strlen("data") );
      zval *priority_val = zend_hash_str_find(Z_ARRVAL_P(val), "priority", strlen("priority"));

      if (!data_val || !priority_val) {
        return FAILURE;
      }

      spl_pqueue_elem elem;
      ZVAL_COPY(&elem.data, data_val);
      ZVAL_COPY(&elem.priority, priority_val);
      spl_ptr_heap_insert(intern->heap, &elem, this_ptr);
      if (EG(exception)) {
        return FAILURE;
      }
    } else {
      Z_TRY_ADDREF_P(val);
      spl_ptr_heap_insert(intern->heap, val, this_ptr);
      if (EG(exception)) {
        return FAILURE;
      }
    }
  } ZEND_HASH_FOREACH_END();

  return SUCCESS;
}

static void spl_heap_serialize_internal(INTERNAL_FUNCTION_PARAMETERS, bool is_pqueue)
{
  spl_heap_object *intern = Z_SPLHEAP_P(ZEND_THIS);
  zval props, state;

  ZEND_PARSE_PARAMETERS_NONE();

  if (UNEXPECTED(spl_heap_consistency_validations(intern, false) != SUCCESS)) {
    RETURN_THROWS();
  }

  if (intern->heap->flags & SPL_HEAP_WRITE_LOCKED) {
    zend_throw_exception(spl_ce_RuntimeException, "Cannot serialize heap while it is being modified.", 0);
    RETURN_THROWS();
  }

  array_init(return_value);

  ZVAL_ARR(&props, zend_array_dup(zend_std_get_properties(&intern->std)));
  zend_hash_next_index_insert(Z_ARRVAL_P(return_value), &props);

  spl_heap_serialize_internal_state(&state, intern, is_pqueue);
  zend_hash_next_index_insert(Z_ARRVAL_P(return_value), &state);
}

PHP_METHOD(SplPriorityQueue, __serialize)
{
  spl_heap_serialize_internal(INTERNAL_FUNCTION_PARAM_PASSTHRU, true);
}

PHP_METHOD(SplPriorityQueue, __unserialize)
{
  HashTable *data;
  spl_heap_object *intern = Z_SPLHEAP_P(ZEND_THIS);

  ZEND_PARSE_PARAMETERS_START(1, 1)
    Z_PARAM_ARRAY_HT(data)
  ZEND_PARSE_PARAMETERS_END();

  if (zend_hash_num_elements(data) != 2) {
    zend_throw_exception_ex(NULL, 0, "Invalid serialization data for %s object", ZSTR_VAL(intern->std.ce->name));
    RETURN_THROWS();
  }

  zval *props = zend_hash_index_find(data, 0);
  if (!props || Z_TYPE_P(props) != IS_ARRAY) {
    zend_throw_exception_ex(NULL, 0, "Invalid serialization data for %s object", ZSTR_VAL(intern->std.ce->name));
    RETURN_THROWS();
  }

  object_properties_load(&intern->std, Z_ARRVAL_P(props));
  if (EG(exception)) {
    zend_throw_exception_ex(NULL, 0, "Invalid serialization data for %s object", ZSTR_VAL(intern->std.ce->name));
    RETURN_THROWS();
  }

  zval *state = zend_hash_index_find(data, 1);
  if (!state || Z_TYPE_P(state) != IS_ARRAY) {
    zend_throw_exception_ex(NULL, 0, "Invalid serialization data for %s object", ZSTR_VAL(intern->std.ce->name));
    RETURN_THROWS();
  }

  if (spl_heap_unserialize_internal_state(Z_ARRVAL_P(state), intern, ZEND_THIS, true) != SUCCESS) {
    zend_throw_exception_ex(NULL, 0, "Invalid serialization data for %s object", ZSTR_VAL(intern->std.ce->name));
    RETURN_THROWS();
  }

  if (EG(exception)) {
    RETURN_THROWS();
  }

  if (UNEXPECTED(spl_heap_consistency_validations(intern, false) != SUCCESS)) {
    RETURN_THROWS();
  }
}

PHP_METHOD(SplHeap, __serialize)
{
  spl_heap_serialize_internal(INTERNAL_FUNCTION_PARAM_PASSTHRU, false);
}

PHP_METHOD(SplHeap, __unserialize)
{
  HashTable *data;
  spl_heap_object *intern = Z_SPLHEAP_P(ZEND_THIS);

  ZEND_PARSE_PARAMETERS_START(1, 1)
    Z_PARAM_ARRAY_HT(data)
  ZEND_PARSE_PARAMETERS_END();

  if (UNEXPECTED(spl_heap_consistency_validations(intern, true) != SUCCESS)) {
    RETURN_THROWS();
  }

  if (zend_hash_num_elements(data) != 2) {
    zend_throw_exception_ex(NULL, 0, "Invalid serialization data for %s object", ZSTR_VAL(intern->std.ce->name));
    RETURN_THROWS();
  }

  zval *props = zend_hash_index_find(data, 0);
  if (!props || Z_TYPE_P(props) != IS_ARRAY) {
    zend_throw_exception_ex(NULL, 0, "Invalid serialization data for %s object", ZSTR_VAL(intern->std.ce->name));
    RETURN_THROWS();
  }

  object_properties_load(&intern->std, Z_ARRVAL_P(props));
  if (EG(exception)) {
    zend_throw_exception_ex(NULL, 0, "Invalid serialization data for %s object", ZSTR_VAL(intern->std.ce->name));
    RETURN_THROWS();
  }

  zval *state = zend_hash_index_find(data, 1);
  if (!state || Z_TYPE_P(state) != IS_ARRAY) {
    zend_throw_exception_ex(NULL, 0, "Invalid serialization data for %s object", ZSTR_VAL(intern->std.ce->name));
    RETURN_THROWS();
  }

  if (spl_heap_unserialize_internal_state(Z_ARRVAL_P(state), intern, ZEND_THIS, false) != SUCCESS) {
    zend_throw_exception_ex(NULL, 0, "Invalid serialization data for %s object", ZSTR_VAL(intern->std.ce->name));
    RETURN_THROWS();
  }

  if (UNEXPECTED(spl_heap_consistency_validations(intern, false) != SUCCESS)) {
    RETURN_THROWS();
  }
}

/* iterator handler table */
static const zend_object_iterator_funcs spl_heap_it_funcs = {
  spl_heap_it_dtor,
  spl_heap_it_valid,
  spl_heap_it_get_current_data,
  spl_heap_it_get_current_key,
  spl_heap_it_move_forward,
  spl_heap_it_rewind,
  NULL,
  NULL, /* get_gc */
};

static const zend_object_iterator_funcs spl_pqueue_it_funcs = {
  spl_heap_it_dtor,
  spl_heap_it_valid,
  spl_pqueue_it_get_current_data,
  spl_heap_it_get_current_key,
  spl_heap_it_move_forward,
  spl_heap_it_rewind,
  NULL,
  NULL, /* get_gc */
};

static zend_object_iterator *spl_heap_get_iterator(zend_class_entry *ce, zval *object, int by_ref) /* {{{ */
{
  if (by_ref) {
    zend_throw_error(NULL, "An iterator cannot be used with foreach by reference");
    return NULL;
  }

  zend_user_iterator *iterator = emalloc(sizeof(zend_user_iterator));
  zend_iterator_init(&iterator->it);

  ZVAL_OBJ_COPY(&iterator->it.data, Z_OBJ_P(object));
  iterator->it.funcs = &spl_heap_it_funcs;
  iterator->ce       = ce;
  ZVAL_UNDEF(&iterator->value);

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

static zend_object_iterator *spl_pqueue_get_iterator(zend_class_entry *ce, zval *object, int by_ref) /* {{{ */
{
  if (by_ref) {
    zend_throw_error(NULL, "An iterator cannot be used with foreach by reference");
    return NULL;
  }

  zend_user_iterator *iterator = emalloc(sizeof(zend_user_iterator));
  zend_iterator_init(&iterator->it);

  ZVAL_OBJ_COPY(&iterator->it.data, Z_OBJ_P(object));
  iterator->it.funcs = &spl_pqueue_it_funcs;
  iterator->ce       = ce;
  ZVAL_UNDEF(&iterator->value);

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

PHP_MINIT_FUNCTION(spl_heap) /* {{{ */
{
  spl_ce_SplHeap = register_class_SplHeap(zend_ce_iterator, zend_ce_countable);
  spl_ce_SplHeap->create_object = spl_heap_object_new;
  spl_ce_SplHeap->default_object_handlers = &spl_handler_SplHeap;
  spl_ce_SplHeap->get_iterator = spl_heap_get_iterator;

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

  spl_handler_SplHeap.offset         = offsetof(spl_heap_object, std);
  spl_handler_SplHeap.clone_obj      = spl_heap_object_clone;
  spl_handler_SplHeap.count_elements = spl_heap_object_count_elements;
  spl_handler_SplHeap.get_gc         = spl_heap_object_get_gc;
  spl_handler_SplHeap.free_obj = spl_heap_object_free_storage;

  spl_ce_SplMinHeap = register_class_SplMinHeap(spl_ce_SplHeap);
  spl_ce_SplMinHeap->create_object = spl_heap_object_new;
  spl_ce_SplMinHeap->get_iterator = spl_heap_get_iterator;

  spl_ce_SplMaxHeap = register_class_SplMaxHeap(spl_ce_SplHeap);
  spl_ce_SplMaxHeap->create_object = spl_heap_object_new;
  spl_ce_SplMaxHeap->get_iterator = spl_heap_get_iterator;

  spl_ce_SplPriorityQueue = register_class_SplPriorityQueue(zend_ce_iterator, zend_ce_countable);
  spl_ce_SplPriorityQueue->create_object = spl_heap_object_new;
  spl_ce_SplPriorityQueue->default_object_handlers = &spl_handler_SplPriorityQueue;
  spl_ce_SplPriorityQueue->get_iterator = spl_pqueue_get_iterator;

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

  spl_handler_SplPriorityQueue.offset         = offsetof(spl_heap_object, std);
  spl_handler_SplPriorityQueue.clone_obj      = spl_heap_object_clone;
  spl_handler_SplPriorityQueue.count_elements = spl_heap_object_count_elements;
  spl_handler_SplPriorityQueue.get_gc         = spl_pqueue_object_get_gc;
  spl_handler_SplPriorityQueue.free_obj = spl_heap_object_free_storage;

  return SUCCESS;
}
/* }}} */

Coverage Report

Created: 2026-06-02 06:39