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diff --git a/erts/emulator/beam/safe_hash.h b/erts/emulator/beam/safe_hash.h
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+++ b/erts/emulator/beam/safe_hash.h
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+/*
+ * %CopyrightBegin%
+ * 
+ * Copyright Ericsson AB 2008-2009. All Rights Reserved.
+ * 
+ * The contents of this file are subject to the Erlang Public License,
+ * Version 1.1, (the "License"); you may not use this file except in
+ * compliance with the License. You should have received a copy of the
+ * Erlang Public License along with this software. If not, it can be
+ * retrieved online at http://www.erlang.org/.
+ * 
+ * Software distributed under the License is distributed on an "AS IS"
+ * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
+ * the License for the specific language governing rights and limitations
+ * under the License.
+ * 
+ * %CopyrightEnd%
+ */
+
+/*
+** General thread safe hash table. Simular interface as hash.h
+**
+** Author: Sverker Eriksson
+*/
+#ifndef __SAFE_HASH_H__
+#define __SAFE_HASH_H__
+
+
+#ifndef __SYS_H__
+#include "sys.h"
+#endif
+
+#include "erl_alloc.h"
+
+
+typedef unsigned long SafeHashValue;
+
+typedef int (*SHCMP_FUN)(void*, void*);
+typedef SafeHashValue (*SH_FUN)(void*);
+typedef void* (*SHALLOC_FUN)(void*);
+typedef void (*SHFREE_FUN)(void*);
+
+/*
+** This bucket must be placed in top of 
+** every object that uses hashing!!!
+** (Object*) == (Object*) &bucket
+*/
+typedef struct safe_hashbucket
+{
+    struct safe_hashbucket* next;	/* Next bucket */
+    SafeHashValue hvalue;           /* Store hash value for get, rehash */
+} SafeHashBucket;
+
+typedef struct safe_hashfunctions
+{
+    SH_FUN hash;
+    SHCMP_FUN cmp;
+    SHALLOC_FUN alloc;
+    SHFREE_FUN free;
+} SafeHashFunctions;
+
+typedef struct {
+  char *name;
+  int   size;
+  int   used;
+  int   objs;
+  int   depth;
+} SafeHashInfo;
+
+#define SAFE_HASH_LOCK_CNT 16
+typedef struct
+{
+    SafeHashFunctions fun;    /* (C) Function block */
+    ErtsAlcType_t type;       /* (C) */
+    char* name;               /* (C) Table name (static, for debugging) */
+    int size_mask;	      /* (RW) Number of slots - 1 */
+    SafeHashBucket** tab;     /* (RW) Vector of bucket pointers (objects) */
+    int grow_limit;           /* (RW) Threshold for growing table */
+    erts_smp_atomic_t nitems;       /* (A) Number of items in table */
+    erts_smp_atomic_t is_rehashing; /* (A) Table rehashing in progress */
+
+    union {
+	erts_smp_mtx_t mtx;
+	byte __cache_line__[64];
+    }lock_vec[SAFE_HASH_LOCK_CNT];
+
+    /* C: Constants initialized once */
+    /* RW: One lock (or is_rehashing) to read and _all_ locks to write */
+    /* A: Lockless atomics */
+} SafeHash;
+
+SafeHash* safe_hash_init(ErtsAlcType_t, SafeHash*, char*, int, SafeHashFunctions);
+
+void  safe_hash_get_info(SafeHashInfo*, SafeHash*);
+int   safe_hash_table_sz(SafeHash *);
+
+void* safe_hash_get(SafeHash*, void*);
+void* safe_hash_put(SafeHash*, void*);
+void* safe_hash_erase(SafeHash*, void*);
+
+void  safe_hash_for_each(SafeHash*, void (*func)(void *, void *), void *);
+
+#endif /* __SAFE_HASH_H__ */
+