--- /dev/null
+/*
+ * Copyright (c) 2008 Apple Inc. All rights reserved.
+ *
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
+ *
+ * This file contains Original Code and/or Modifications of Original Code
+ * as defined in and that are subject to the Apple Public Source License
+ * Version 2.0 (the 'License'). You may not use this file except in
+ * compliance with the License. The rights granted to you under the License
+ * may not be used to create, or enable the creation or redistribution of,
+ * unlawful or unlicensed copies of an Apple operating system, or to
+ * circumvent, violate, or enable the circumvention or violation of, any
+ * terms of an Apple operating system software license agreement.
+ *
+ * Please obtain a copy of the License at
+ * http://www.opensource.apple.com/apsl/ and read it before using this file.
+ *
+ * The Original Code and all software distributed under the License are
+ * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
+ * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
+ * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
+ * Please see the License for the specific language governing rights and
+ * limitations under the License.
+ *
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
+ */
+#ifndef _KXLD_ARRAY_H_
+#define _KXLD_ARRAY_H_
+
+#include <sys/queue.h>
+#include <sys/types.h>
+#if KERNEL
+ #include <libkern/kxld_types.h>
+#else
+ #include "kxld_types.h"
+#endif
+
+/*******************************************************************************
+* This is a resizeable array implementation designed primarily to maximize
+* memory reuse. The array should only be allocated once, but it can be
+* initialized many times. It persists its memory across initializations, and
+* reallocates only if it needs to grow the internal array, such that memory
+* allocation churn is eliminated. Growth is accomodated by building a linked
+* list of identically sized arrays. These arrays can be consolidated into
+* one large array in the init function.
+*
+* A technique commonly used in kxld is to make an array of objects that
+* themselves contain kxld_arrays. To minimize memory churn across links, only
+* the individual objects contained in an array should be cleared at the end of
+* each link, such that they are in a state ready for reinitialization with the
+* memory they have already allocated. The array that contains them should not
+* be cleared. After all links are complete, to ensure that all memory is
+* properly freed, one should call kxld_array_get_slot to walk the entire
+* allocated space of the array and clean up all potential instances contained
+* therein. Since this technique is somewhat fragile, there are certain
+* requirements that must be met, and guarantees that the array implementation
+* provides.
+*
+* Requirements:
+* - A newly allocated, uninitialized array object must be zeroed out before
+* it is initialized
+* - The objects stored in the array that will be reused must consider
+* being bzeroed a valid initial state. Specifially, they must check that
+* pointers they contain are nonnull before they are freed or followed
+* at both construction and destruction time.
+*
+* Guarantees:
+* - The init function will always bzero newly allocated memory. If memory
+* is added by resizing, it will bzero only the newly allocated portion.
+* - clear, deinit, and copy are the only functions that will change the
+* contents of initialized memory.
+* - The reset, clear, deinit functions will accept a NULL pointer to an array.
+*******************************************************************************/
+
+STAILQ_HEAD(kxld_array_head, kxld_array_pool);
+
+struct kxld_array {
+ struct kxld_array_head pools;
+ size_t itemsize; /* The size of the items that the array contains */
+ size_t pool_capacity; /* The size of each pool's internal buffer */
+ u_int pool_maxitems; /* The maximum number of items each pool can hold
+ * given the current size of each pool's buffer.
+ */
+ u_int nitems; /* The current number of items this array contains */
+ u_int maxitems; /* The maximum number of items this array can contain */
+ u_int npools; /* The number of pools in the pool list */
+};
+
+struct kxld_array_pool {
+ STAILQ_ENTRY(kxld_array_pool) entries;
+ u_char *buffer; /* The internal memory buffer */
+ u_int nitems; /* The number of items the array contains */
+};
+
+typedef struct kxld_array KXLDArray;
+typedef struct kxld_array_head KXLDArrayHead;
+typedef struct kxld_array_pool KXLDArrayPool;
+
+/*******************************************************************************
+* Constructors and Destructors
+*******************************************************************************/
+
+/* Initializes the array's capacity to a minimum of nitems * itemsize */
+kern_return_t kxld_array_init(KXLDArray *array, size_t itemsize, u_int nitems)
+ __attribute__((nonnull, visibility("hidden")));
+
+/* Performs a deep copy of the array */
+kern_return_t kxld_array_copy(KXLDArray *array, const KXLDArray *src)
+ __attribute__((nonnull, visibility("hidden")));
+
+/* Sets the number of items in the array to 0 */
+void kxld_array_reset(KXLDArray *array)
+ __attribute__((visibility("hidden")));
+
+/* Zeroes out the array and sets nitems to 0 */
+void kxld_array_clear(KXLDArray *array)
+ __attribute__((visibility("hidden")));
+
+/* Frees the array's internal buffer */
+void kxld_array_deinit(KXLDArray *array)
+ __attribute__((visibility("hidden")));
+
+/*******************************************************************************
+* Accessors
+*******************************************************************************/
+
+/* Returns the item at the specified index, or NULL if idx > nitems */
+void *kxld_array_get_item(const KXLDArray *array, u_int idx)
+ __attribute__((pure, nonnull, visibility("hidden")));
+
+/* Returns the item at the specified index, or NULL if idx > maxitems */
+void *kxld_array_get_slot(const KXLDArray *array, u_int idx)
+ __attribute__((pure, nonnull, visibility("hidden")));
+
+/* Returns the index of a specified item in the array */
+kern_return_t kxld_array_get_index(const KXLDArray *array, const void *item,
+ u_int *idx)
+ __attribute__((nonnull, visibility("hidden")));
+
+/*******************************************************************************
+* Modifiers
+*******************************************************************************/
+
+/* Grows the array to contain a minimum of nitems. If extra memory is needed,
+ * it will allocate a pool and add it to the list of pools maintained by this
+ * array.
+ */
+kern_return_t kxld_array_resize(KXLDArray *array, u_int nitems)
+ __attribute__((nonnull, visibility("hidden")));
+
+/* Removes an element from the array. This is only supported for arrays with
+ * a single pool.
+ */
+kern_return_t kxld_array_remove(KXLDArray *array, u_int idx)
+ __attribute__((nonnull, visibility("hidden")));
+
+#endif /* _KXLD_ARRAY_H_ */