--- /dev/null
+++ libmalloc/libmalloc-715.100.22/src/magazine_rack.h
@@ -0,0 +1,128 @@
+/*
+ * Copyright (c) 2016 Apple Inc. All rights reserved.
+ *
+ * @APPLE_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. 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_LICENSE_HEADER_END@
+ */
+
+#ifndef __MAGAZINE_RACK_H
+#define __MAGAZINE_RACK_H
+
+#include <malloc/_ptrcheck.h>
+__ptrcheck_abi_assume_single()
+
+/*******************************************************************************
+ * Definitions for region hash
+ ******************************************************************************/
+
+typedef void * __single region_t;
+typedef region_t * __single rgnhdl_t; /* A pointer into hashed_regions array. */
+typedef struct region_trailer region_trailer_t;
+
+#define INITIAL_NUM_REGIONS_SHIFT 6							 // log2(INITIAL_NUM_REGIONS)
+#define INITIAL_NUM_REGIONS (1 << INITIAL_NUM_REGIONS_SHIFT) // Must be a power of 2!
+#define HASHRING_OPEN_ENTRY ((region_t)0)					 // Initial value and sentinel marking end of collision chain
+#define HASHRING_REGION_DEALLOCATED __unsafe_forge_single(void *, ~0UL)			 // Region at this slot reclaimed by OS
+#define HASH_BLOCKS_ALIGN TINY_BLOCKS_ALIGN					 // MIN( TINY_BLOCKS_ALIGN, SMALL_BLOCKS_ALIGN, ... )
+
+typedef struct region_hash_generation {
+	size_t num_regions_allocated;
+	size_t num_regions_allocated_shift; // log2(num_regions_allocated)
+	region_t * __counted_by(num_regions_allocated) hashed_regions;			// hashed by location
+	struct region_hash_generation *nextgen;
+} region_hash_generation_t;
+
+OS_ENUM(rack_type, uint32_t,
+	RACK_TYPE_NONE = 0,
+	RACK_TYPE_TINY,
+	RACK_TYPE_SMALL,
+	RACK_TYPE_MEDIUM,
+);
+
+/*******************************************************************************
+ * Per-allocator collection of regions and magazines
+ ******************************************************************************/
+
+typedef struct rack_s {
+	/* Regions for tiny objects */
+	_malloc_lock_s region_lock MALLOC_CACHE_ALIGN;
+
+	rack_type_t type;
+	size_t num_regions;
+	size_t num_regions_dealloc;
+	region_hash_generation_t *region_generation;
+	region_hash_generation_t rg[2];
+	region_t initial_regions[INITIAL_NUM_REGIONS];
+
+	int num_magazines;
+	unsigned num_magazines_mask;
+	int num_magazines_mask_shift;
+	uint32_t debug_flags;
+
+	// array of per-processor magazines
+	magazine_t *magazines;
+
+	uintptr_t cookie;
+	uintptr_t last_madvise;
+} rack_t;
+
+MALLOC_NOEXPORT
+void
+rack_init(rack_t *rack, rack_type_t type, uint32_t num_magazines, uint32_t debug_flags);
+
+MALLOC_NOEXPORT
+void
+rack_destroy_regions(rack_t *rack, size_t region_size);
+
+MALLOC_NOEXPORT
+void
+rack_destroy(rack_t *rack);
+
+MALLOC_NOEXPORT
+void
+rack_region_insert(rack_t *rack, region_t region);
+
+MALLOC_NOEXPORT
+bool
+rack_region_remove(rack_t *rack, region_t region, region_trailer_t *trailer);
+
+MALLOC_NOEXPORT
+bool
+rack_region_maybe_dispose(rack_t *rack, region_t region, size_t region_size,
+		region_trailer_t *trailer);
+
+MALLOC_NOEXPORT
+unsigned int
+rack_get_thread_index(rack_t *rack);
+
+MALLOC_NOEXPORT MALLOC_ALWAYS_INLINE MALLOC_INLINE
+static void
+rack_region_lock(rack_t *rack)
+{
+	_malloc_lock_lock(&rack->region_lock);
+}
+
+MALLOC_NOEXPORT MALLOC_ALWAYS_INLINE MALLOC_INLINE
+static void
+rack_region_unlock(rack_t *rack)
+{
+	_malloc_lock_unlock(&rack->region_lock);
+}
+
+#endif // __MAGAZINE_RACK_H