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Comparing jsr166/src/jsr166e/ConcurrentHashMapV8.java (file contents):
Revision 1.23 by jsr166, Sun Sep 11 04:25:00 2011 UTC vs.
Revision 1.39 by jsr166, Sat Jun 9 16:54:12 2012 UTC

#	Line 4 | Line 4
4		* http://creativecommons.org/publicdomain/zero/1.0/
5		*/
6
7	+	// Snapshot Tue Jun  5 14:56:09 2012  Doug Lea  (dl at altair)
8	+
9		package jsr166e;
10		import jsr166e.LongAdder;
11	+	import java.util.Arrays;
12		import java.util.Map;
13		import java.util.Set;
14		import java.util.Collection;
#	Line 19 | Line 22 | import java.util.Enumeration;
22		import java.util.ConcurrentModificationException;
23		import java.util.NoSuchElementException;
24		import java.util.concurrent.ConcurrentMap;
25	+	import java.util.concurrent.ThreadLocalRandom;
26	+	import java.util.concurrent.locks.LockSupport;
27	+	import java.util.concurrent.locks.AbstractQueuedSynchronizer;
28		import java.io.Serializable;
29
30		/**
#	Line 54 | Line 60 | import java.io.Serializable;
60		* <p> The table is dynamically expanded when there are too many
61		* collisions (i.e., keys that have distinct hash codes but fall into
62		* the same slot modulo the table size), with the expected average
63	<	* effect of maintaining roughly two bins per mapping. There may be
64	<	* much variance around this average as mappings are added and
65	<	* removed, but overall, this maintains a commonly accepted time/space
66	<	* tradeoff for hash tables.  However, resizing this or any other kind
67	<	* of hash table may be a relatively slow operation. When possible, it
68	<	* is a good idea to provide a size estimate as an optional {@code
63	>	* effect of maintaining roughly two bins per mapping (corresponding
64	>	* to a 0.75 load factor threshold for resizing). There may be much
65	>	* variance around this average as mappings are added and removed, but
66	>	* overall, this maintains a commonly accepted time/space tradeoff for
67	>	* hash tables.  However, resizing this or any other kind of hash
68	>	* table may be a relatively slow operation. When possible, it is a
69	>	* good idea to provide a size estimate as an optional {@code
70		* initialCapacity} constructor argument. An additional optional
71		* {@code loadFactor} constructor argument provides a further means of
72		* customizing initial table capacity by specifying the table density
#	Line 68 | Line 75 | import java.io.Serializable;
75		* versions of this class, constructors may optionally specify an
76		* expected {@code concurrencyLevel} as an additional hint for
77		* internal sizing.  Note that using many keys with exactly the same
78	<	* {@code hashCode{}} is a sure way to slow down performance of any
78	>	* {@code hashCode()} is a sure way to slow down performance of any
79		* hash table.
80		*
81		* <p>This class and its views and iterators implement all of the
#	Line 95 | Line 102 | public class ConcurrentHashMapV8<K, V>
102		private static final long serialVersionUID = 7249069246763182397L;
103
104		/**
105	<	* A function computing a mapping from the given key to a value,
106	<	* or {@code null} if there is no mapping. This is a place-holder
100	<	* for an upcoming JDK8 interface.
105	>	* A function computing a mapping from the given key to a value.
106	>	* This is a place-holder for an upcoming JDK8 interface.
107		*/
108		public static interface MappingFunction<K, V> {
109		/**
110	<	* Returns a value for the given key, or null if there is no
105	<	* mapping. If this function throws an (unchecked) exception,
106	<	* the exception is rethrown to its caller, and no mapping is
107	<	* recorded.  Because this function is invoked within
108	<	* atomicity control, the computation should be short and
109	<	* simple. The most common usage is to construct a new object
110	<	* serving as an initial mapped value.
110	>	* Returns a non-null value for the given key.
111		*
112		* @param key the (non-null) key
113	<	* @return a value, or null if none
113	>	* @return a non-null value
114		*/
115		V map(K key);
116		}
117
118	+	/**
119	+	* A function computing a new mapping given a key and its current
120	+	* mapped value (or {@code null} if there is no current
121	+	* mapping). This is a place-holder for an upcoming JDK8
122	+	* interface.
123	+	*/
124	+	public static interface RemappingFunction<K, V> {
125	+	/**
126	+	* Returns a new value given a key and its current value.
127	+	*
128	+	* @param key the (non-null) key
129	+	* @param value the current value, or null if there is no mapping
130	+	* @return a non-null value
131	+	*/
132	+	V remap(K key, V value);
133	+	}
134	+
135		/*
136		* Overview:
137		*
138		* The primary design goal of this hash table is to maintain
139		* concurrent readability (typically method get(), but also
140		* iterators and related methods) while minimizing update
141	<	* contention.
141	>	* contention. Secondary goals are to keep space consumption about
142	>	* the same or better than java.util.HashMap, and to support high
143	>	* initial insertion rates on an empty table by many threads.
144		*
145		* Each key-value mapping is held in a Node.  Because Node fields
146		* can contain special values, they are defined using plain Object
#	Line 129 | Line 148 | public class ConcurrentHashMapV8<K, V>
148		* work off Object types. And similarly, so do the internal
149		* methods of auxiliary iterator and view classes.  All public
150		* generic typed methods relay in/out of these internal methods,
151	<	* supplying null-checks and casts as needed.
151	>	* supplying null-checks and casts as needed. This also allows
152	>	* many of the public methods to be factored into a smaller number
153	>	* of internal methods (although sadly not so for the five
154	>	* variants of put-related operations). The validation-based
155	>	* approach explained below leads to a lot of code sprawl because
156	>	* retry-control precludes factoring into smaller methods.
157		*
158		* The table is lazily initialized to a power-of-two size upon the
159	<	* first insertion.  Each bin in the table contains a list of
160	<	* Nodes (most often, zero or one Node).  Table accesses require
161	<	* volatile/atomic reads, writes, and CASes.  Because there is no
162	<	* other way to arrange this without adding further indirections,
163	<	* we use intrinsics (sun.misc.Unsafe) operations.  The lists of
164	<	* nodes within bins are always accurately traversable under
165	<	* volatile reads, so long as lookups check hash code and
166	<	* non-nullness of value before checking key equality. (All valid
167	<	* hash codes are nonnegative. Negative values are reserved for
168	<	* special forwarding nodes; see below.)
159	>	* first insertion.  Each bin in the table normally contains a
160	>	* list of Nodes (most often, the list has only zero or one Node).
161	>	* Table accesses require volatile/atomic reads, writes, and
162	>	* CASes.  Because there is no other way to arrange this without
163	>	* adding further indirections, we use intrinsics
164	>	* (sun.misc.Unsafe) operations.  The lists of nodes within bins
165	>	* are always accurately traversable under volatile reads, so long
166	>	* as lookups check hash code and non-nullness of value before
167	>	* checking key equality.
168	>	*
169	>	* We use the top two bits of Node hash fields for control
170	>	* purposes -- they are available anyway because of addressing
171	>	* constraints.  As explained further below, these top bits are
172	>	* used as follows:
173	>	*  00 - Normal
174	>	*  01 - Locked
175	>	*  11 - Locked and may have a thread waiting for lock
176	>	*  10 - Node is a forwarding node
177	>	*
178	>	* The lower 30 bits of each Node's hash field contain a
179	>	* transformation of the key's hash code, except for forwarding
180	>	* nodes, for which the lower bits are zero (and so always have
181	>	* hash field == MOVED).
182		*
183	<	* Insertion (via put or putIfAbsent) of the first node in an
183	>	* Insertion (via put or its variants) of the first node in an
184		* empty bin is performed by just CASing it to the bin.  This is
185	<	* on average by far the most common case for put operations.
186	<	* Other update operations (insert, delete, and replace) require
187	<	* locks.  We do not want to waste the space required to associate
188	<	* a distinct lock object with each bin, so instead use the first
189	<	* node of a bin list itself as a lock, using plain "synchronized"
190	<	* locks. These save space and we can live with block-structured
191	<	* lock/unlock operations. Using the first node of a list as a
192	<	* lock does not by itself suffice though. When a node is locked,
193	<	* any update must first validate that it is still the first node,
194	<	* and retry if not. Because new nodes are always appended to
195	<	* lists, once a node is first in a bin, it remains first until
196	<	* deleted or the bin becomes invalidated.  However, operations
197	<	* that only conditionally update can and sometimes do inspect
198	<	* nodes until the point of update. This is a converse of sorts to
199	<	* the lazy locking technique described by Herlihy & Shavit.
185	>	* by far the most common case for put operations under most
186	>	* key/hash distributions.  Other update operations (insert,
187	>	* delete, and replace) require locks.  We do not want to waste
188	>	* the space required to associate a distinct lock object with
189	>	* each bin, so instead use the first node of a bin list itself as
190	>	* a lock. Blocking support for these locks relies on the builtin
191	>	* "synchronized" monitors.  However, we also need a tryLock
192	>	* construction, so we overlay these by using bits of the Node
193	>	* hash field for lock control (see above), and so normally use
194	>	* builtin monitors only for blocking and signalling using
195	>	* wait/notifyAll constructions. See Node.tryAwaitLock.
196	>	*
197	>	* Using the first node of a list as a lock does not by itself
198	>	* suffice though: When a node is locked, any update must first
199	>	* validate that it is still the first node after locking it, and
200	>	* retry if not. Because new nodes are always appended to lists,
201	>	* once a node is first in a bin, it remains first until deleted
202	>	* or the bin becomes invalidated (upon resizing).  However,
203	>	* operations that only conditionally update may inspect nodes
204	>	* until the point of update. This is a converse of sorts to the
205	>	* lazy locking technique described by Herlihy & Shavit.
206		*
207	<	* The main disadvantage of this approach is that most update
207	>	* The main disadvantage of per-bin locks is that other update
208		* operations on other nodes in a bin list protected by the same
209		* lock can stall, for example when user equals() or mapping
210	<	* functions take a long time.  However, statistically, this is
211	<	* not a common enough problem to outweigh the time/space overhead
212	<	* of alternatives: Under random hash codes, the frequency of
170	<	* nodes in bins follows a Poisson distribution
210	>	* functions take a long time.  However, statistically, under
211	>	* random hash codes, this is not a common problem.  Ideally, the
212	>	* frequency of nodes in bins follows a Poisson distribution
213		* (http://en.wikipedia.org/wiki/Poisson_distribution) with a
214		* parameter of about 0.5 on average, given the resizing threshold
215		* of 0.75, although with a large variance because of resizing
216		* granularity. Ignoring variance, the expected occurrences of
217		* list size k are (exp(-0.5) * pow(0.5, k) / factorial(k)). The
218	<	* first few values are:
218	>	* first values are:
219		*
220	<	* 0:    0.607
221	<	* 1:    0.303
222	<	* 2:    0.076
223	<	* 3:    0.012
224	<	* more: 0.002
220	>	* 0:    0.60653066
221	>	* 1:    0.30326533
222	>	* 2:    0.07581633
223	>	* 3:    0.01263606
224	>	* 4:    0.00157952
225	>	* 5:    0.00015795
226	>	* 6:    0.00001316
227	>	* 7:    0.00000094
228	>	* 8:    0.00000006
229	>	* more: less than 1 in ten million
230		*
231		* Lock contention probability for two threads accessing distinct
232	<	* elements is roughly 1 / (8 * #elements).  Function "spread"
186	<	* performs hashCode randomization that improves the likelihood
187	<	* that these assumptions hold unless users define exactly the
188	<	* same value for too many hashCodes.
189	<	*
190	<	* The table is resized when occupancy exceeds a threshold.  Only
191	<	* a single thread performs the resize (using field "resizing", to
192	<	* arrange exclusion), but the table otherwise remains usable for
193	<	* reads and updates. Resizing proceeds by transferring bins, one
194	<	* by one, from the table to the next table.  Upon transfer, the
195	<	* old table bin contains only a special forwarding node (with
196	<	* negative hash field) that contains the next table as its
197	<	* key. On encountering a forwarding node, access and update
198	<	* operations restart, using the new table. To ensure concurrent
199	<	* readability of traversals, transfers must proceed from the last
200	<	* bin (table.length - 1) up towards the first.  Upon seeing a
201	<	* forwarding node, traversals (see class InternalIterator)
202	<	* arrange to move to the new table for the rest of the traversal
203	<	* without revisiting nodes.  This constrains bin transfers to a
204	<	* particular order, and so can block indefinitely waiting for the
205	<	* next lock, and other threads cannot help with the transfer.
206	<	* However, expected stalls are infrequent enough to not warrant
207	<	* the additional overhead of access and iteration schemes that
208	<	* could admit out-of-order or concurrent bin transfers.
232	>	* elements is roughly 1 / (8 * #elements) under random hashes.
233		*
234	<	* This traversal scheme also applies to partial traversals of
234	>	* Actual hash code distributions encountered in practice
235	>	* sometimes deviate significantly from uniform randomness.  This
236	>	* includes the case when N > (1<<30), so some keys MUST collide.
237	>	* Similarly for dumb or hostile usages in which multiple keys are
238	>	* designed to have identical hash codes. Also, although we guard
239	>	* against the worst effects of this (see method spread), sets of
240	>	* hashes may differ only in bits that do not impact their bin
241	>	* index for a given power-of-two mask.  So we use a secondary
242	>	* strategy that applies when the number of nodes in a bin exceeds
243	>	* a threshold, and at least one of the keys implements
244	>	* Comparable.  These TreeBins use a balanced tree to hold nodes
245	>	* (a specialized form of red-black trees), bounding search time
246	>	* to O(log N).  Each search step in a TreeBin is around twice as
247	>	* slow as in a regular list, but given that N cannot exceed
248	>	* (1<<64) (before running out of addresses) this bounds search
249	>	* steps, lock hold times, etc, to reasonable constants (roughly
250	>	* 100 nodes inspected per operation worst case) so long as keys
251	>	* are Comparable (which is very common -- String, Long, etc).
252	>	* TreeBin nodes (TreeNodes) also maintain the same "next"
253	>	* traversal pointers as regular nodes, so can be traversed in
254	>	* iterators in the same way.
255	>	*
256	>	* The table is resized when occupancy exceeds a percentage
257	>	* threshold (nominally, 0.75, but see below).  Only a single
258	>	* thread performs the resize (using field "sizeCtl", to arrange
259	>	* exclusion), but the table otherwise remains usable for reads
260	>	* and updates. Resizing proceeds by transferring bins, one by
261	>	* one, from the table to the next table.  Because we are using
262	>	* power-of-two expansion, the elements from each bin must either
263	>	* stay at same index, or move with a power of two offset. We
264	>	* eliminate unnecessary node creation by catching cases where old
265	>	* nodes can be reused because their next fields won't change.  On
266	>	* average, only about one-sixth of them need cloning when a table
267	>	* doubles. The nodes they replace will be garbage collectable as
268	>	* soon as they are no longer referenced by any reader thread that
269	>	* may be in the midst of concurrently traversing table.  Upon
270	>	* transfer, the old table bin contains only a special forwarding
271	>	* node (with hash field "MOVED") that contains the next table as
272	>	* its key. On encountering a forwarding node, access and update
273	>	* operations restart, using the new table.
274	>	*
275	>	* Each bin transfer requires its bin lock. However, unlike other
276	>	* cases, a transfer can skip a bin if it fails to acquire its
277	>	* lock, and revisit it later (unless it is a TreeBin). Method
278	>	* rebuild maintains a buffer of TRANSFER_BUFFER_SIZE bins that
279	>	* have been skipped because of failure to acquire a lock, and
280	>	* blocks only if none are available (i.e., only very rarely).
281	>	* The transfer operation must also ensure that all accessible
282	>	* bins in both the old and new table are usable by any traversal.
283	>	* When there are no lock acquisition failures, this is arranged
284	>	* simply by proceeding from the last bin (table.length - 1) up
285	>	* towards the first.  Upon seeing a forwarding node, traversals
286	>	* (see class InternalIterator) arrange to move to the new table
287	>	* without revisiting nodes.  However, when any node is skipped
288	>	* during a transfer, all earlier table bins may have become
289	>	* visible, so are initialized with a reverse-forwarding node back
290	>	* to the old table until the new ones are established. (This
291	>	* sometimes requires transiently locking a forwarding node, which
292	>	* is possible under the above encoding.) These more expensive
293	>	* mechanics trigger only when necessary.
294	>	*
295	>	* The traversal scheme also applies to partial traversals of
296		* ranges of bins (via an alternate InternalIterator constructor)
297		* to support partitioned aggregate operations (that are not
298		* otherwise implemented yet).  Also, read-only operations give up
#	Line 218 | Line 303 | public class ConcurrentHashMapV8<K, V>
303		* Lazy table initialization minimizes footprint until first use,
304		* and also avoids resizings when the first operation is from a
305		* putAll, constructor with map argument, or deserialization.
306	<	* These cases attempt to override the targetCapacity used in
307	<	* growTable. These harmlessly fail to take effect in cases of
223	<	* races with other ongoing resizings. Uses of the threshold and
224	<	* targetCapacity during attempted initializations or resizings
225	<	* are racy but fall back on checks to preserve correctness.
306	>	* These cases attempt to override the initial capacity settings,
307	>	* but harmlessly fail to take effect in cases of races.
308		*
309		* The element count is maintained using a LongAdder, which avoids
310		* contention on updates but can encounter cache thrashing if read
311		* too frequently during concurrent access. To avoid reading so
312	<	* often, resizing is normally attempted only upon adding to a bin
313	<	* already holding two or more nodes. Under uniform hash
314	<	* distributions, the probability of this occurring at threshold
315	<	* is around 13%, meaning that only about 1 in 8 puts check
316	<	* threshold (and after resizing, many fewer do so). But this
317	<	* approximation has high variance for small table sizes, so we
318	<	* check on any collision for sizes <= 64.  Further, to increase
319	<	* the probability that a resize occurs soon enough, we offset the
320	<	* threshold (see THRESHOLD_OFFSET) by the expected number of puts
321	<	* between checks.
312	>	* often, resizing is attempted either when a bin lock is
313	>	* contended, or upon adding to a bin already holding two or more
314	>	* nodes (checked before adding in the xIfAbsent methods, after
315	>	* adding in others). Under uniform hash distributions, the
316	>	* probability of this occurring at threshold is around 13%,
317	>	* meaning that only about 1 in 8 puts check threshold (and after
318	>	* resizing, many fewer do so). But this approximation has high
319	>	* variance for small table sizes, so we check on any collision
320	>	* for sizes <= 64. The bulk putAll operation further reduces
321	>	* contention by only committing count updates upon these size
322	>	* checks.
323		*
324		* Maintaining API and serialization compatibility with previous
325		* versions of this class introduces several oddities. Mainly: We
326		* leave untouched but unused constructor arguments refering to
327	<	* concurrencyLevel. We also declare an unused "Segment" class
328	<	* that is instantiated in minimal form only when serializing.
327	>	* concurrencyLevel. We accept a loadFactor constructor argument,
328	>	* but apply it only to initial table capacity (which is the only
329	>	* time that we can guarantee to honor it.) We also declare an
330	>	* unused "Segment" class that is instantiated in minimal form
331	>	* only when serializing.
332		*/
333
334		/* ---------------- Constants -------------- */
#	Line 250 | Line 336 | public class ConcurrentHashMapV8<K, V>
336		/**
337		* The largest possible table capacity.  This value must be
338		* exactly 1<<30 to stay within Java array allocation and indexing
339	<	* bounds for power of two table sizes.
339	>	* bounds for power of two table sizes, and is further required
340	>	* because the top two bits of 32bit hash fields are used for
341	>	* control purposes.
342		*/
343		private static final int MAXIMUM_CAPACITY = 1 << 30;
344
#	Line 261 | Line 349 | public class ConcurrentHashMapV8<K, V>
349		private static final int DEFAULT_CAPACITY = 16;
350
351		/**
352	<	* The load factor for this table. Overrides of this value in
353	<	* constructors affect only the initial table capacity.  The
266	<	* actual floating point value isn't normally used, because it is
267	<	* simpler to rely on the expression {@code n - (n >>> 2)} for the
268	<	* associated resizing threshold.
352	>	* The largest possible (non-power of two) array size.
353	>	* Needed by toArray and related methods.
354		*/
355	<	private static final float LOAD_FACTOR = 0.75f;
355	>	static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8;
356
357		/**
358	<	* The count value to offset thresholds to compensate for checking
359	<	* for the need to resize only when inserting into bins with two
275	<	* or more elements. See above for explanation.
358	>	* The default concurrency level for this table. Unused but
359	>	* defined for compatibility with previous versions of this class.
360		*/
361	<	private static final int THRESHOLD_OFFSET = 8;
361	>	private static final int DEFAULT_CONCURRENCY_LEVEL = 16;
362
363		/**
364	<	* The default concurrency level for this table. Unused except as
365	<	* a sizing hint, but defined for compatibility with previous
366	<	* versions of this class.
364	>	* The load factor for this table. Overrides of this value in
365	>	* constructors affect only the initial table capacity.  The
366	>	* actual floating point value isn't normally used -- it is
367	>	* simpler to use expressions such as {@code n - (n >>> 2)} for
368	>	* the associated resizing threshold.
369		*/
370	<	private static final int DEFAULT_CONCURRENCY_LEVEL = 16;
285	<
286	<	/* ---------------- Nodes -------------- */
370	>	private static final float LOAD_FACTOR = 0.75f;
371
372		/**
373	<	* Key-value entry. Note that this is never exported out as a
374	<	* user-visible Map.Entry. Nodes with a negative hash field are
375	<	* special, and do not contain user keys or values.  Otherwise,
292	<	* keys are never null, and null val fields indicate that a node
293	<	* is in the process of being deleted or created. For purposes of
294	<	* read-only access, a key may be read before a val, but can only
295	<	* be used after checking val.  (For an update operation, when a
296	<	* lock is held on a node, order doesn't matter.)
373	>	* The buffer size for skipped bins during transfers. The
374	>	* value is arbitrary but should be large enough to avoid
375	>	* most locking stalls during resizes.
376		*/
377	<	static final class Node {
299	<	final int hash;
300	<	final Object key;
301	<	volatile Object val;
302	<	volatile Node next;
303	<
304	<	Node(int hash, Object key, Object val, Node next) {
305	<	this.hash = hash;
306	<	this.key = key;
307	<	this.val = val;
308	<	this.next = next;
309	<	}
310	<	}
377	>	private static final int TRANSFER_BUFFER_SIZE = 32;
378
379		/**
380	<	* Sign bit of node hash value indicating to use table in node.key.
380	>	* The bin count threshold for using a tree rather than list for a
381	>	* bin.  The value reflects the approximate break-even point for
382	>	* using tree-based operations.
383		*/
384	<	private static final int SIGN_BIT = 0x80000000;
384	>	private static final int TREE_THRESHOLD = 8;
385	>
386	>	/*
387	>	* Encodings for special uses of Node hash fields. See above for
388	>	* explanation.
389	>	*/
390	>	static final int MOVED     = 0x80000000; // hash field for forwarding nodes
391	>	static final int LOCKED    = 0x40000000; // set/tested only as a bit
392	>	static final int WAITING   = 0xc0000000; // both bits set/tested together
393	>	static final int HASH_BITS = 0x3fffffff; // usable bits of normal node hash
394
395		/* ---------------- Fields -------------- */
396
#	Line 322 | Line 400 | public class ConcurrentHashMapV8<K, V>
400		*/
401		transient volatile Node[] table;
402
403	<	/** The counter maintaining number of elements. */
403	>	/**
404	>	* The counter maintaining number of elements.
405	>	*/
406		private transient final LongAdder counter;
407	<	/** Nonzero when table is being initialized or resized. Updated via CAS. */
408	<	private transient volatile int resizing;
409	<	/** The next element count value upon which to resize the table. */
410	<	private transient int threshold;
411	<	/** The target capacity; volatile to cover initialization races. */
412	<	private transient volatile int targetCapacity;
407	>
408	>	/**
409	>	* Table initialization and resizing control.  When negative, the
410	>	* table is being initialized or resized. Otherwise, when table is
411	>	* null, holds the initial table size to use upon creation, or 0
412	>	* for default. After initialization, holds the next element count
413	>	* value upon which to resize the table.
414	>	*/
415	>	private transient volatile int sizeCtl;
416
417		// views
418		private transient KeySet<K,V> keySet;
#	Line 365 | Line 448 | public class ConcurrentHashMapV8<K, V>
448		UNSAFE.putObjectVolatile(tab, ((long)i<<ASHIFT)+ABASE, v);
449		}
450
451	<	/* ----------------Table Initialization and Resizing -------------- */
451	>	/* ---------------- Nodes -------------- */
452
453		/**
454	<	* Returns a power of two table size for the given desired capacity.
455	<	* See Hackers Delight, sec 3.2
454	>	* Key-value entry. Note that this is never exported out as a
455	>	* user-visible Map.Entry (see WriteThroughEntry and SnapshotEntry
456	>	* below). Nodes with a hash field of MOVED are special, and do
457	>	* not contain user keys or values.  Otherwise, keys are never
458	>	* null, and null val fields indicate that a node is in the
459	>	* process of being deleted or created. For purposes of read-only
460	>	* access, a key may be read before a val, but can only be used
461	>	* after checking val to be non-null.
462		*/
463	<	private static final int tableSizeFor(int c) {
464	<	int n = c - 1;
465	<	n |= n >>> 1;
466	<	n |= n >>> 2;
467	<	n |= n >>> 4;
468	<	n |= n >>> 8;
469	<	n |= n >>> 16;
470	<	return (n < 0) ? 1 : (n >= MAXIMUM_CAPACITY) ? MAXIMUM_CAPACITY : n + 1;
463	>	static class Node {
464	>	volatile int hash;
465	>	final Object key;
466	>	volatile Object val;
467	>	volatile Node next;
468	>
469	>	Node(int hash, Object key, Object val, Node next) {
470	>	this.hash = hash;
471	>	this.key = key;
472	>	this.val = val;
473	>	this.next = next;
474	>	}
475	>
476	>	/** CompareAndSet the hash field */
477	>	final boolean casHash(int cmp, int val) {
478	>	return UNSAFE.compareAndSwapInt(this, hashOffset, cmp, val);
479	>	}
480	>
481	>	/** The number of spins before blocking for a lock */
482	>	static final int MAX_SPINS =
483	>	Runtime.getRuntime().availableProcessors() > 1 ? 64 : 1;
484	>
485	>	/**
486	>	* Spins a while if LOCKED bit set and this node is the first
487	>	* of its bin, and then sets WAITING bits on hash field and
488	>	* blocks (once) if they are still set.  It is OK for this
489	>	* method to return even if lock is not available upon exit,
490	>	* which enables these simple single-wait mechanics.
491	>	*
492	>	* The corresponding signalling operation is performed within
493	>	* callers: Upon detecting that WAITING has been set when
494	>	* unlocking lock (via a failed CAS from non-waiting LOCKED
495	>	* state), unlockers acquire the sync lock and perform a
496	>	* notifyAll.
497	>	*/
498	>	final void tryAwaitLock(Node[] tab, int i) {
499	>	if (tab != null && i >= 0 && i < tab.length) { // bounds check
500	>	int r = ThreadLocalRandom.current().nextInt(); // randomize spins
501	>	int spins = MAX_SPINS, h;
502	>	while (tabAt(tab, i) == this && ((h = hash) & LOCKED) != 0) {
503	>	if (spins >= 0) {
504	>	r ^= r << 1; r ^= r >>> 3; r ^= r << 10; // xorshift
505	>	if (r >= 0 && --spins == 0)
506	>	Thread.yield();  // yield before block
507	>	}
508	>	else if (casHash(h, h | WAITING)) {
509	>	synchronized (this) {
510	>	if (tabAt(tab, i) == this &&
511	>	(hash & WAITING) == WAITING) {
512	>	try {
513	>	wait();
514	>	} catch (InterruptedException ie) {
515	>	Thread.currentThread().interrupt();
516	>	}
517	>	}
518	>	else
519	>	notifyAll(); // possibly won race vs signaller
520	>	}
521	>	break;
522	>	}
523	>	}
524	>	}
525	>	}
526	>
527	>	// Unsafe mechanics for casHash
528	>	private static final sun.misc.Unsafe UNSAFE;
529	>	private static final long hashOffset;
530	>
531	>	static {
532	>	try {
533	>	UNSAFE = getUnsafe();
534	>	Class<?> k = Node.class;
535	>	hashOffset = UNSAFE.objectFieldOffset
536	>	(k.getDeclaredField("hash"));
537	>	} catch (Exception e) {
538	>	throw new Error(e);
539	>	}
540	>	}
541		}
542
543	+	/* ---------------- TreeBins -------------- */
544	+
545		/**
546	<	* If not already resizing, initializes or creates next table and
547	<	* transfers bins. Initial table size uses the capacity recorded
548	<	* in targetCapacity.  Rechecks occupancy after a transfer to see
549	<	* if another resize is already needed because resizings are
550	<	* lagging additions.
551	<	*
552	<	* @return current table
553	<	*/
554	<	private final Node[] growTable() {
555	<	if (resizing == 0 &&
556	<	UNSAFE.compareAndSwapInt(this, resizingOffset, 0, 1)) {
557	<	try {
546	>	* Nodes for use in TreeBins
547	>	*/
548	>	static final class TreeNode extends Node {
549	>	TreeNode parent;  // red-black tree links
550	>	TreeNode left;
551	>	TreeNode right;
552	>	TreeNode prev;    // needed to unlink next upon deletion
553	>	boolean red;
554	>
555	>	TreeNode(int hash, Object key, Object val, Node next, TreeNode parent) {
556	>	super(hash, key, val, next);
557	>	this.parent = parent;
558	>	}
559	>	}
560	>
561	>	/**
562	>	* A specialized form of red-black tree for use in bins
563	>	* whose size exceeds a threshold.
564	>	*
565	>	* TreeBins use a special form of comparison for search and
566	>	* related operations (which is the main reason we cannot use
567	>	* existing collections such as TreeMaps). TreeBins contain
568	>	* Comparable elements, but may contain others, as well as
569	>	* elements that are Comparable but not necessarily Comparable<T>
570	>	* for the same T, so we cannot invoke compareTo among them. To
571	>	* handle this, the tree is ordered primarily by hash value, then
572	>	* by getClass().getName() order, and then by Comparator order
573	>	* among elements of the same class.  On lookup at a node, if
574	>	* non-Comparable, both left and right children may need to be
575	>	* searched in the case of tied hash values. (This corresponds to
576	>	* the full list search that would be necessary if all elements
577	>	* were non-Comparable and had tied hashes.)
578	>	*
579	>	* TreeBins also maintain a separate locking discipline than
580	>	* regular bins. Because they are forwarded via special MOVED
581	>	* nodes at bin heads (which can never change once established),
582	>	* we cannot use use those nodes as locks. Instead, TreeBin
583	>	* extends AbstractQueuedSynchronizer to support a simple form of
584	>	* read-write lock. For update operations and table validation,
585	>	* the exclusive form of lock behaves in the same way as bin-head
586	>	* locks. However, lookups use shared read-lock mechanics to allow
587	>	* multiple readers in the absence of writers.  Additionally,
588	>	* these lookups do not ever block: While the lock is not
589	>	* available, they proceed along the slow traversal path (via
590	>	* next-pointers) until the lock becomes available or the list is
591	>	* exhausted, whichever comes first. (These cases are not fast,
592	>	* but maximize aggregate expected throughput.)  The AQS mechanics
593	>	* for doing this are straightforward.  The lock state is held as
594	>	* AQS getState().  Read counts are negative; the write count (1)
595	>	* is positive.  There are no signalling preferences among readers
596	>	* and writers. Since we don't need to export full Lock API, we
597	>	* just override the minimal AQS methods and use them directly.
598	>	*/
599	>	static final class TreeBin extends AbstractQueuedSynchronizer {
600	>	private static final long serialVersionUID = 2249069246763182397L;
601	>	TreeNode root;  // root of tree
602	>	TreeNode first; // head of next-pointer list
603	>
604	>	/* AQS overrides */
605	>	public final boolean isHeldExclusively() { return getState() > 0; }
606	>	public final boolean tryAcquire(int ignore) {
607	>	if (compareAndSetState(0, 1)) {
608	>	setExclusiveOwnerThread(Thread.currentThread());
609	>	return true;
610	>	}
611	>	return false;
612	>	}
613	>	public final boolean tryRelease(int ignore) {
614	>	setExclusiveOwnerThread(null);
615	>	setState(0);
616	>	return true;
617	>	}
618	>	public final int tryAcquireShared(int ignore) {
619	>	for (int c;;) {
620	>	if ((c = getState()) > 0)
621	>	return -1;
622	>	if (compareAndSetState(c, c -1))
623	>	return 1;
624	>	}
625	>	}
626	>	public final boolean tryReleaseShared(int ignore) {
627	>	int c;
628	>	do {} while (!compareAndSetState(c = getState(), c + 1));
629	>	return c == -1;
630	>	}
631	>
632	>	/**
633	>	* Return the TreeNode (or null if not found) for the given key
634	>	* starting at given root.
635	>	*/
636	>	@SuppressWarnings("unchecked") // suppress Comparable cast warning
637	>	final TreeNode getTreeNode(int h, Object k, TreeNode p) {
638	>	Class<?> c = k.getClass();
639	>	while (p != null) {
640	>	int dir, ph;  Object pk; Class<?> pc; TreeNode r;
641	>	if (h < (ph = p.hash))
642	>	dir = -1;
643	>	else if (h > ph)
644	>	dir = 1;
645	>	else if ((pk = p.key) == k || k.equals(pk))
646	>	return p;
647	>	else if (c != (pc = pk.getClass()))
648	>	dir = c.getName().compareTo(pc.getName());
649	>	else if (k instanceof Comparable)
650	>	dir = ((Comparable)k).compareTo((Comparable)pk);
651	>	else
652	>	dir = 0;
653	>	TreeNode pr = p.right;
654	>	if (dir > 0)
655	>	p = pr;
656	>	else if (dir == 0 && pr != null && h >= pr.hash &&
657	>	(r = getTreeNode(h, k, pr)) != null)
658	>	return r;
659	>	else
660	>	p = p.left;
661	>	}
662	>	return null;
663	>	}
664	>
665	>	/**
666	>	* Wrapper for getTreeNode used by CHM.get. Tries to obtain
667	>	* read-lock to call getTreeNode, but during failure to get
668	>	* lock, searches along next links.
669	>	*/
670	>	final Object getValue(int h, Object k) {
671	>	Node r = null;
672	>	int c = getState(); // Must read lock state first
673	>	for (Node e = first; e != null; e = e.next) {
674	>	if (c <= 0 && compareAndSetState(c, c - 1)) {
675	>	try {
676	>	r = getTreeNode(h, k, root);
677	>	} finally {
678	>	releaseShared(0);
679	>	}
680	>	break;
681	>	}
682	>	else if ((e.hash & HASH_BITS) == h && k.equals(e.key)) {
683	>	r = e;
684	>	break;
685	>	}
686	>	else
687	>	c = getState();
688	>	}
689	>	return r == null ? null : r.val;
690	>	}
691	>
692	>	/**
693	>	* Find or add a node
694	>	* @return null if added
695	>	*/
696	>	@SuppressWarnings("unchecked") // suppress Comparable cast warning
697	>	final TreeNode putTreeNode(int h, Object k, Object v) {
698	>	Class<?> c = k.getClass();
699	>	TreeNode p = root;
700	>	int dir = 0;
701	>	if (p != null) {
702		for (;;) {
703	<	Node[] tab = table;
704	<	int n, c, m;
705	<	if (tab == null)
706	<	n = (c = targetCapacity) > 0 ? c : DEFAULT_CAPACITY;
707	<	else if ((m = tab.length) < MAXIMUM_CAPACITY &&
708	<	counter.sum() >= (long)threshold)
709	<	n = m << 1;
703	>	int ph;  Object pk; Class<?> pc; TreeNode r;
704	>	if (h < (ph = p.hash))
705	>	dir = -1;
706	>	else if (h > ph)
707	>	dir = 1;
708	>	else if ((pk = p.key) == k || k.equals(pk))
709	>	return p;
710	>	else if (c != (pc = (pk = p.key).getClass()))
711	>	dir = c.getName().compareTo(pc.getName());
712	>	else if (k instanceof Comparable)
713	>	dir = ((Comparable)k).compareTo((Comparable)pk);
714		else
715	+	dir = 0;
716	+	TreeNode pr = p.right, pl;
717	+	if (dir > 0) {
718	+	if (pr == null)
719	+	break;
720	+	p = pr;
721	+	}
722	+	else if (dir == 0 && pr != null && h >= pr.hash &&
723	+	(r = getTreeNode(h, k, pr)) != null)
724	+	return r;
725	+	else if ((pl = p.left) == null)
726		break;
727	<	threshold = n - (n >>> 2) - THRESHOLD_OFFSET;
728	<	Node[] nextTab = new Node[n];
409	<	if (tab != null)
410	<	transfer(tab, nextTab,
411	<	new Node(SIGN_BIT, nextTab, null, null));
412	<	table = nextTab;
413	<	if (tab == null)
414	<	break;
727	>	else
728	>	p = pl;
729		}
416	–	} finally {
417	–	resizing = 0;
730		}
731	+	TreeNode f = first;
732	+	TreeNode r = first = new TreeNode(h, k, v, f, p);
733	+	if (p == null)
734	+	root = r;
735	+	else {
736	+	if (dir <= 0)
737	+	p.left = r;
738	+	else
739	+	p.right = r;
740	+	if (f != null)
741	+	f.prev = r;
742	+	fixAfterInsertion(r);
743	+	}
744	+	return null;
745		}
420	–	else if (table == null)
421	–	Thread.yield(); // lost initialization race; just spin
422	–	return table;
423	–	}
746
747	<	/**
748	<	* Reclassifies nodes in each bin to new table.  Because we are
749	<	* using power-of-two expansion, the elements from each bin must
750	<	* either stay at same index, or move with a power of two
751	<	* offset. We eliminate unnecessary node creation by catching
752	<	* cases where old nodes can be reused because their next fields
753	<	* won't change.  Statistically, only about one-sixth of them need
754	<	* cloning when a table doubles. The nodes they replace will be
755	<	* garbage collectable as soon as they are no longer referenced by
756	<	* any reader thread that may be in the midst of concurrently
757	<	* traversing table.
758	<	*
759	<	* Transfers are done from the bottom up to preserve iterator
760	<	* traversability. On each step, the old bin is locked,
761	<	* moved/copied, and then replaced with a forwarding node.
762	<	*/
763	<	private static final void transfer(Node[] tab, Node[] nextTab, Node fwd) {
764	<	int n = tab.length;
765	<	Node ignore = nextTab[n + n - 1]; // force bounds check
766	<	for (int i = n - 1; i >= 0; --i) {
767	<	for (Node e;;) {
768	<	if ((e = tabAt(tab, i)) != null) {
769	<	boolean validated = false;
770	<	synchronized (e) {
771	<	if (tabAt(tab, i) == e) {
772	<	validated = true;
773	<	Node lo = null, hi = null, lastRun = e;
774	<	int runBit = e.hash & n;
775	<	for (Node p = e.next; p != null; p = p.next) {
776	<	int b = p.hash & n;
777	<	if (b != runBit) {
778	<	runBit = b;
779	<	lastRun = p;
780	<	}
747	>	/**
748	>	* Removes the given node, that must be present before this
749	>	* call.  This is messier than typical red-black deletion code
750	>	* because we cannot swap the contents of an interior node
751	>	* with a leaf successor that is pinned by "next" pointers
752	>	* that are accessible independently of lock. So instead we
753	>	* swap the tree linkages.
754	>	*/
755	>	final void deleteTreeNode(TreeNode p) {
756	>	TreeNode next = (TreeNode)p.next; // unlink traversal pointers
757	>	TreeNode pred = p.prev;
758	>	if (pred == null)
759	>	first = next;
760	>	else
761	>	pred.next = next;
762	>	if (next != null)
763	>	next.prev = pred;
764	>	TreeNode replacement;
765	>	TreeNode pl = p.left;
766	>	TreeNode pr = p.right;
767	>	if (pl != null && pr != null) {
768	>	TreeNode s = pr;
769	>	while (s.left != null) // find successor
770	>	s = s.left;
771	>	boolean c = s.red; s.red = p.red; p.red = c; // swap colors
772	>	TreeNode sr = s.right;
773	>	TreeNode pp = p.parent;
774	>	if (s == pr) { // p was s's direct parent
775	>	p.parent = s;
776	>	s.right = p;
777	>	}
778	>	else {
779	>	TreeNode sp = s.parent;
780	>	if ((p.parent = sp) != null) {
781	>	if (s == sp.left)
782	>	sp.left = p;
783	>	else
784	>	sp.right = p;
785	>	}
786	>	if ((s.right = pr) != null)
787	>	pr.parent = s;
788	>	}
789	>	p.left = null;
790	>	if ((p.right = sr) != null)
791	>	sr.parent = p;
792	>	if ((s.left = pl) != null)
793	>	pl.parent = s;
794	>	if ((s.parent = pp) == null)
795	>	root = s;
796	>	else if (p == pp.left)
797	>	pp.left = s;
798	>	else
799	>	pp.right = s;
800	>	replacement = sr;
801	>	}
802	>	else
803	>	replacement = (pl != null) ? pl : pr;
804	>	TreeNode pp = p.parent;
805	>	if (replacement == null) {
806	>	if (pp == null) {
807	>	root = null;
808	>	return;
809	>	}
810	>	replacement = p;
811	>	}
812	>	else {
813	>	replacement.parent = pp;
814	>	if (pp == null)
815	>	root = replacement;
816	>	else if (p == pp.left)
817	>	pp.left = replacement;
818	>	else
819	>	pp.right = replacement;
820	>	p.left = p.right = p.parent = null;
821	>	}
822	>	if (!p.red)
823	>	fixAfterDeletion(replacement);
824	>	if (p == replacement && (pp = p.parent) != null) {
825	>	if (p == pp.left) // detach pointers
826	>	pp.left = null;
827	>	else if (p == pp.right)
828	>	pp.right = null;
829	>	p.parent = null;
830	>	}
831	>	}
832	>
833	>	// CLR code updated from pre-jdk-collections version at
834	>	// http://gee.cs.oswego.edu/dl/classes/collections/RBCell.java
835	>
836	>	/** From CLR */
837	>	private void rotateLeft(TreeNode p) {
838	>	if (p != null) {
839	>	TreeNode r = p.right, pp, rl;
840	>	if ((rl = p.right = r.left) != null)
841	>	rl.parent = p;
842	>	if ((pp = r.parent = p.parent) == null)
843	>	root = r;
844	>	else if (pp.left == p)
845	>	pp.left = r;
846	>	else
847	>	pp.right = r;
848	>	r.left = p;
849	>	p.parent = r;
850	>	}
851	>	}
852	>
853	>	/** From CLR */
854	>	private void rotateRight(TreeNode p) {
855	>	if (p != null) {
856	>	TreeNode l = p.left, pp, lr;
857	>	if ((lr = p.left = l.right) != null)
858	>	lr.parent = p;
859	>	if ((pp = l.parent = p.parent) == null)
860	>	root = l;
861	>	else if (pp.right == p)
862	>	pp.right = l;
863	>	else
864	>	pp.left = l;
865	>	l.right = p;
866	>	p.parent = l;
867	>	}
868	>	}
869	>
870	>	/** From CLR */
871	>	private void fixAfterInsertion(TreeNode x) {
872	>	x.red = true;
873	>	TreeNode xp, xpp;
874	>	while (x != null && (xp = x.parent) != null && xp.red &&
875	>	(xpp = xp.parent) != null) {
876	>	TreeNode xppl = xpp.left;
877	>	if (xp == xppl) {
878	>	TreeNode y = xpp.right;
879	>	if (y != null && y.red) {
880	>	y.red = false;
881	>	xp.red = false;
882	>	xpp.red = true;
883	>	x = xpp;
884	>	}
885	>	else {
886	>	if (x == xp.right) {
887	>	x = xp;
888	>	rotateLeft(x);
889	>	xpp = (xp = x.parent) == null ? null : xp.parent;
890	>	}
891	>	if (xp != null) {
892	>	xp.red = false;
893	>	if (xpp != null) {
894	>	xpp.red = true;
895	>	rotateRight(xpp);
896		}
897	<	if (runBit == 0)
898	<	lo = lastRun;
899	<	else
900	<	hi = lastRun;
901	<	for (Node p = e; p != lastRun; p = p.next) {
902	<	int ph = p.hash;
903	<	Object pk = p.key, pv = p.val;
904	<	if ((ph & n) == 0)
905	<	lo = new Node(ph, pk, pv, lo);
906	<	else
907	<	hi = new Node(ph, pk, pv, hi);
897	>	}
898	>	}
899	>	}
900	>	else {
901	>	TreeNode y = xppl;
902	>	if (y != null && y.red) {
903	>	y.red = false;
904	>	xp.red = false;
905	>	xpp.red = true;
906	>	x = xpp;
907	>	}
908	>	else {
909	>	if (x == xp.left) {
910	>	x = xp;
911	>	rotateRight(x);
912	>	xpp = (xp = x.parent) == null ? null : xp.parent;
913	>	}
914	>	if (xp != null) {
915	>	xp.red = false;
916	>	if (xpp != null) {
917	>	xpp.red = true;
918	>	rotateLeft(xpp);
919		}
472	–	setTabAt(nextTab, i, lo);
473	–	setTabAt(nextTab, i + n, hi);
474	–	setTabAt(tab, i, fwd);
920		}
921		}
477	–	if (validated)
478	–	break;
922		}
923	<	else if (casTabAt(tab, i, e, fwd))
923	>	}
924	>	TreeNode r = root;
925	>	if (r != null && r.red)
926	>	r.red = false;
927	>	}
928	>
929	>	/** From CLR */
930	>	private void fixAfterDeletion(TreeNode x) {
931	>	while (x != null) {
932	>	TreeNode xp, xpl;
933	>	if (x.red || (xp = x.parent) == null) {
934	>	x.red = false;
935		break;
936	+	}
937	+	if (x == (xpl = xp.left)) {
938	+	TreeNode sib = xp.right;
939	+	if (sib != null && sib.red) {
940	+	sib.red = false;
941	+	xp.red = true;
942	+	rotateLeft(xp);
943	+	sib = (xp = x.parent) == null ? null : xp.right;
944	+	}
945	+	if (sib == null)
946	+	x = xp;
947	+	else {
948	+	TreeNode sl = sib.left, sr = sib.right;
949	+	if ((sr == null || !sr.red) &&
950	+	(sl == null || !sl.red)) {
951	+	sib.red = true;
952	+	x = xp;
953	+	}
954	+	else {
955	+	if (sr == null || !sr.red) {
956	+	if (sl != null)
957	+	sl.red = false;
958	+	sib.red = true;
959	+	rotateRight(sib);
960	+	sib = (xp = x.parent) == null ? null : xp.right;
961	+	}
962	+	if (sib != null) {
963	+	sib.red = (xp == null) ? false : xp.red;
964	+	if ((sr = sib.right) != null)
965	+	sr.red = false;
966	+	}
967	+	if (xp != null) {
968	+	xp.red = false;
969	+	rotateLeft(xp);
970	+	}
971	+	x = root;
972	+	}
973	+	}
974	+	}
975	+	else { // symmetric
976	+	TreeNode sib = xpl;
977	+	if (sib != null && sib.red) {
978	+	sib.red = false;
979	+	xp.red = true;
980	+	rotateRight(xp);
981	+	sib = (xp = x.parent) == null ? null : xp.left;
982	+	}
983	+	if (sib == null)
984	+	x = xp;
985	+	else {
986	+	TreeNode sl = sib.left, sr = sib.right;
987	+	if ((sl == null || !sl.red) &&
988	+	(sr == null || !sr.red)) {
989	+	sib.red = true;
990	+	x = xp;
991	+	}
992	+	else {
993	+	if (sl == null || !sl.red) {
994	+	if (sr != null)
995	+	sr.red = false;
996	+	sib.red = true;
997	+	rotateLeft(sib);
998	+	sib = (xp = x.parent) == null ? null : xp.left;
999	+	}
1000	+	if (sib != null) {
1001	+	sib.red = (xp == null) ? false : xp.red;
1002	+	if ((sl = sib.left) != null)
1003	+	sl.red = false;
1004	+	}
1005	+	if (xp != null) {
1006	+	xp.red = false;
1007	+	rotateRight(xp);
1008	+	}
1009	+	x = root;
1010	+	}
1011	+	}
1012	+	}
1013		}
1014		}
1015		}
1016
1017	<	/* ---------------- Internal access and update methods -------------- */
1017	>	/* ---------------- Collision reduction methods -------------- */
1018
1019		/**
1020	<	* Applies a supplemental hash function to a given hashCode, which
1021	<	* defends against poor quality hash functions.  The result must
1022	<	* be non-negative, and for reasonable performance must have good
1023	<	* avalanche properties; i.e., that each bit of the argument
1024	<	* affects each bit (except sign bit) of the result.
1020	>	* Spreads higher bits to lower, and also forces top 2 bits to 0.
1021	>	* Because the table uses power-of-two masking, sets of hashes
1022	>	* that vary only in bits above the current mask will always
1023	>	* collide. (Among known examples are sets of Float keys holding
1024	>	* consecutive whole numbers in small tables.)  To counter this,
1025	>	* we apply a transform that spreads the impact of higher bits
1026	>	* downward. There is a tradeoff between speed, utility, and
1027	>	* quality of bit-spreading. Because many common sets of hashes
1028	>	* are already reaonably distributed across bits (so don't benefit
1029	>	* from spreading), and because we use trees to handle large sets
1030	>	* of collisions in bins, we don't need excessively high quality.
1031		*/
1032		private static final int spread(int h) {
1033	<	// Apply base step of MurmurHash; see http://code.google.com/p/smhasher/
1034	<	h ^= h >>> 16;
498	<	h *= 0x85ebca6b;
499	<	h ^= h >>> 13;
500	<	h *= 0xc2b2ae35;
501	<	return (h >>> 16) ^ (h & 0x7fffffff); // mask out sign bit
1033	>	h ^= (h >>> 18) ^ (h >>> 12);
1034	>	return (h ^ (h >>> 10)) & HASH_BITS;
1035		}
1036
1037	+	/**
1038	+	* Replaces a list bin with a tree bin. Call only when locked.
1039	+	* Fails to replace if the given key is non-comparable or table
1040	+	* is, or needs, resizing.
1041	+	*/
1042	+	private final void replaceWithTreeBin(Node[] tab, int index, Object key) {
1043	+	if ((key instanceof Comparable) &&
1044	+	(tab.length >= MAXIMUM_CAPACITY || counter.sum() < (long)sizeCtl)) {
1045	+	TreeBin t = new TreeBin();
1046	+	for (Node e = tabAt(tab, index); e != null; e = e.next)
1047	+	t.putTreeNode(e.hash & HASH_BITS, e.key, e.val);
1048	+	setTabAt(tab, index, new Node(MOVED, t, null, null));
1049	+	}
1050	+	}
1051	+
1052	+	/* ---------------- Internal access and update methods -------------- */
1053	+
1054		/** Implementation for get and containsKey */
1055		private final Object internalGet(Object k) {
1056		int h = spread(k.hashCode());
1057		retry: for (Node[] tab = table; tab != null;) {
1058	<	Node e; Object ek, ev; int eh;  // locals to read fields once
1058	>	Node e, p; Object ek, ev; int eh;      // locals to read fields once
1059		for (e = tabAt(tab, (tab.length - 1) & h); e != null; e = e.next) {
1060	<	if ((eh = e.hash) == h) {
1061	<	if ((ev = e.val) != null &&
1062	<	((ek = e.key) == k || k.equals(ek)))
1063	<	return ev;
1064	<	}
1065	<	else if (eh < 0) {          // sign bit set
1066	<	tab = (Node[])e.key;    // bin was moved during resize
517	<	continue retry;
1060	>	if ((eh = e.hash) == MOVED) {
1061	>	if ((ek = e.key) instanceof TreeBin)  // search TreeBin
1062	>	return ((TreeBin)ek).getValue(h, k);
1063	>	else {                        // restart with new table
1064	>	tab = (Node[])ek;
1065	>	continue retry;
1066	>	}
1067		}
1068	+	else if ((eh & HASH_BITS) == h && (ev = e.val) != null &&
1069	+	((ek = e.key) == k || k.equals(ek)))
1070	+	return ev;
1071		}
1072		break;
1073		}
1074		return null;
1075		}
1076
1077	<	/** Implementation for put and putIfAbsent */
1078	<	private final Object internalPut(Object k, Object v, boolean replace) {
1077	>	/**
1078	>	* Implementation for the four public remove/replace methods:
1079	>	* Replaces node value with v, conditional upon match of cv if
1080	>	* non-null.  If resulting value is null, delete.
1081	>	*/
1082	>	private final Object internalReplace(Object k, Object v, Object cv) {
1083		int h = spread(k.hashCode());
1084	<	Object oldVal = null;               // previous value or null if none
1084	>	Object oldVal = null;
1085		for (Node[] tab = table;;) {
1086	<	Node e; int i; Object ek, ev;
1086	>	Node f; int i, fh; Object fk;
1087	>	if (tab == null ||
1088	>	(f = tabAt(tab, i = (tab.length - 1) & h)) == null)
1089	>	break;
1090	>	else if ((fh = f.hash) == MOVED) {
1091	>	if ((fk = f.key) instanceof TreeBin) {
1092	>	TreeBin t = (TreeBin)fk;
1093	>	boolean validated = false;
1094	>	boolean deleted = false;
1095	>	t.acquire(0);
1096	>	try {
1097	>	if (tabAt(tab, i) == f) {
1098	>	validated = true;
1099	>	TreeNode p = t.getTreeNode(h, k, t.root);
1100	>	if (p != null) {
1101	>	Object pv = p.val;
1102	>	if (cv == null || cv == pv || cv.equals(pv)) {
1103	>	oldVal = pv;
1104	>	if ((p.val = v) == null) {
1105	>	deleted = true;
1106	>	t.deleteTreeNode(p);
1107	>	}
1108	>	}
1109	>	}
1110	>	}
1111	>	} finally {
1112	>	t.release(0);
1113	>	}
1114	>	if (validated) {
1115	>	if (deleted)
1116	>	counter.add(-1L);
1117	>	break;
1118	>	}
1119	>	}
1120	>	else
1121	>	tab = (Node[])fk;
1122	>	}
1123	>	else if ((fh & HASH_BITS) != h && f.next == null) // precheck
1124	>	break;                          // rules out possible existence
1125	>	else if ((fh & LOCKED) != 0) {
1126	>	checkForResize();               // try resizing if can't get lock
1127	>	f.tryAwaitLock(tab, i);
1128	>	}
1129	>	else if (f.casHash(fh, fh | LOCKED)) {
1130	>	boolean validated = false;
1131	>	boolean deleted = false;
1132	>	try {
1133	>	if (tabAt(tab, i) == f) {
1134	>	validated = true;
1135	>	for (Node e = f, pred = null;;) {
1136	>	Object ek, ev;
1137	>	if ((e.hash & HASH_BITS) == h &&
1138	>	((ev = e.val) != null) &&
1139	>	((ek = e.key) == k || k.equals(ek))) {
1140	>	if (cv == null || cv == ev || cv.equals(ev)) {
1141	>	oldVal = ev;
1142	>	if ((e.val = v) == null) {
1143	>	deleted = true;
1144	>	Node en = e.next;
1145	>	if (pred != null)
1146	>	pred.next = en;
1147	>	else
1148	>	setTabAt(tab, i, en);
1149	>	}
1150	>	}
1151	>	break;
1152	>	}
1153	>	pred = e;
1154	>	if ((e = e.next) == null)
1155	>	break;
1156	>	}
1157	>	}
1158	>	} finally {
1159	>	if (!f.casHash(fh | LOCKED, fh)) {
1160	>	f.hash = fh;
1161	>	synchronized (f) { f.notifyAll(); };
1162	>	}
1163	>	}
1164	>	if (validated) {
1165	>	if (deleted)
1166	>	counter.add(-1L);
1167	>	break;
1168	>	}
1169	>	}
1170	>	}
1171	>	return oldVal;
1172	>	}
1173	>
1174	>	/*
1175	>	* Internal versions of the five insertion methods, each a
1176	>	* little more complicated than the last. All have
1177	>	* the same basic structure as the first (internalPut):
1178	>	*  1. If table uninitialized, create
1179	>	*  2. If bin empty, try to CAS new node
1180	>	*  3. If bin stale, use new table
1181	>	*  4. if bin converted to TreeBin, validate and relay to TreeBin methods
1182	>	*  5. Lock and validate; if valid, scan and add or update
1183	>	*
1184	>	* The others interweave other checks and/or alternative actions:
1185	>	*  * Plain put checks for and performs resize after insertion.
1186	>	*  * putIfAbsent prescans for mapping without lock (and fails to add
1187	>	*    if present), which also makes pre-emptive resize checks worthwhile.
1188	>	*  * computeIfAbsent extends form used in putIfAbsent with additional
1189	>	*    mechanics to deal with, calls, potential exceptions and null
1190	>	*    returns from function call.
1191	>	*  * compute uses the same function-call mechanics, but without
1192	>	*    the prescans
1193	>	*  * putAll attempts to pre-allocate enough table space
1194	>	*    and more lazily performs count updates and checks.
1195	>	*
1196	>	* Someday when details settle down a bit more, it might be worth
1197	>	* some factoring to reduce sprawl.
1198	>	*/
1199	>
1200	>	/** Implementation for put */
1201	>	private final Object internalPut(Object k, Object v) {
1202	>	int h = spread(k.hashCode());
1203	>	int count = 0;
1204	>	for (Node[] tab = table;;) {
1205	>	int i; Node f; int fh; Object fk;
1206		if (tab == null)
1207	<	tab = growTable();
1208	<	else if ((e = tabAt(tab, i = (tab.length - 1) & h)) == null) {
1207	>	tab = initTable();
1208	>	else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
1209		if (casTabAt(tab, i, null, new Node(h, k, v, null)))
1210		break;                   // no lock when adding to empty bin
1211		}
1212	<	else if (e.hash < 0)             // resized -- restart with new table
1213	<	tab = (Node[])e.key;
1214	<	else if (!replace && e.hash == h && (ev = e.val) != null &&
1215	<	((ek = e.key) == k || k.equals(ek))) {
1216	<	if (tabAt(tab, i) == e) {    // inspect and validate 1st node
1217	<	oldVal = ev;             // without lock for putIfAbsent
1218	<	break;
1212	>	else if ((fh = f.hash) == MOVED) {
1213	>	if ((fk = f.key) instanceof TreeBin) {
1214	>	TreeBin t = (TreeBin)fk;
1215	>	Object oldVal = null;
1216	>	t.acquire(0);
1217	>	try {
1218	>	if (tabAt(tab, i) == f) {
1219	>	count = 2;
1220	>	TreeNode p = t.putTreeNode(h, k, v);
1221	>	if (p != null) {
1222	>	oldVal = p.val;
1223	>	p.val = v;
1224	>	}
1225	>	}
1226	>	} finally {
1227	>	t.release(0);
1228	>	}
1229	>	if (count != 0) {
1230	>	if (oldVal != null)
1231	>	return oldVal;
1232	>	break;
1233	>	}
1234		}
1235	+	else
1236	+	tab = (Node[])fk;
1237		}
1238	<	else {
1239	<	boolean validated = false;
1240	<	boolean checkSize = false;
1241	<	synchronized (e) {           // lock the 1st node of bin list
1242	<	if (tabAt(tab, i) == e) {
1243	<	validated = true;    // retry if 1st already deleted
1244	<	for (Node first = e;;) {
1245	<	if (e.hash == h &&
1246	<	((ek = e.key) == k || k.equals(ek)) &&
1247	<	(ev = e.val) != null) {
1238	>	else if ((fh & LOCKED) != 0) {
1239	>	checkForResize();
1240	>	f.tryAwaitLock(tab, i);
1241	>	}
1242	>	else if (f.casHash(fh, fh | LOCKED)) {
1243	>	Object oldVal = null;
1244	>	try {                        // needed in case equals() throws
1245	>	if (tabAt(tab, i) == f) {
1246	>	count = 1;
1247	>	for (Node e = f;; ++count) {
1248	>	Object ek, ev;
1249	>	if ((e.hash & HASH_BITS) == h &&
1250	>	(ev = e.val) != null &&
1251	>	((ek = e.key) == k || k.equals(ek))) {
1252		oldVal = ev;
1253	<	if (replace)
558	<	e.val = v;
1253	>	e.val = v;
1254		break;
1255		}
1256		Node last = e;
1257		if ((e = e.next) == null) {
1258		last.next = new Node(h, k, v, null);
1259	<	if (last != first || tab.length <= 64)
1260	<	checkSize = true;
1259	>	if (count >= TREE_THRESHOLD)
1260	>	replaceWithTreeBin(tab, i, k);
1261		break;
1262		}
1263		}
1264		}
1265	+	} finally {                  // unlock and signal if needed
1266	+	if (!f.casHash(fh | LOCKED, fh)) {
1267	+	f.hash = fh;
1268	+	synchronized (f) { f.notifyAll(); };
1269	+	}
1270		}
1271	<	if (validated) {
1272	<	if (checkSize && tab.length < MAXIMUM_CAPACITY &&
1273	<	resizing == 0 && counter.sum() >= (long)threshold)
1274	<	growTable();
1271	>	if (count != 0) {
1272	>	if (oldVal != null)
1273	>	return oldVal;
1274	>	if (tab.length <= 64)
1275	>	count = 2;
1276		break;
1277		}
1278		}
1279		}
1280	<	if (oldVal == null)
1281	<	counter.increment();             // update counter outside of locks
1282	<	return oldVal;
1280	>	counter.add(1L);
1281	>	if (count > 1)
1282	>	checkForResize();
1283	>	return null;
1284		}
1285
1286	<	/**
1287	<	* Implementation for the four public remove/replace methods:
586	<	* Replaces node value with v, conditional upon match of cv if
587	<	* non-null.  If resulting value is null, delete.
588	<	*/
589	<	private final Object internalReplace(Object k, Object v, Object cv) {
1286	>	/** Implementation for putIfAbsent */
1287	>	private final Object internalPutIfAbsent(Object k, Object v) {
1288		int h = spread(k.hashCode());
1289	+	int count = 0;
1290		for (Node[] tab = table;;) {
1291	<	Node e; int i;
1292	<	if (tab == null ||
1293	<	(e = tabAt(tab, i = (tab.length - 1) & h)) == null)
1294	<	return null;
1295	<	else if (e.hash < 0)
1296	<	tab = (Node[])e.key;
1291	>	int i; Node f; int fh; Object fk, fv;
1292	>	if (tab == null)
1293	>	tab = initTable();
1294	>	else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
1295	>	if (casTabAt(tab, i, null, new Node(h, k, v, null)))
1296	>	break;
1297	>	}
1298	>	else if ((fh = f.hash) == MOVED) {
1299	>	if ((fk = f.key) instanceof TreeBin) {
1300	>	TreeBin t = (TreeBin)fk;
1301	>	Object oldVal = null;
1302	>	t.acquire(0);
1303	>	try {
1304	>	if (tabAt(tab, i) == f) {
1305	>	count = 2;
1306	>	TreeNode p = t.putTreeNode(h, k, v);
1307	>	if (p != null)
1308	>	oldVal = p.val;
1309	>	}
1310	>	} finally {
1311	>	t.release(0);
1312	>	}
1313	>	if (count != 0) {
1314	>	if (oldVal != null)
1315	>	return oldVal;
1316	>	break;
1317	>	}
1318	>	}
1319	>	else
1320	>	tab = (Node[])fk;
1321	>	}
1322	>	else if ((fh & HASH_BITS) == h && (fv = f.val) != null &&
1323	>	((fk = f.key) == k || k.equals(fk)))
1324	>	return fv;
1325		else {
1326	<	Object oldVal = null;
1327	<	boolean validated = false;
1328	<	boolean deleted = false;
1329	<	synchronized (e) {
1330	<	if (tabAt(tab, i) == e) {
1331	<	validated = true;
1332	<	Node pred = null;
1333	<	do {
1334	<	Object ek, ev;
1335	<	if (e.hash == h &&
1336	<	((ek = e.key) == k || k.equals(ek)) &&
1337	<	((ev = e.val) != null)) {
1338	<	if (cv == null || cv == ev || cv.equals(ev)) {
1326	>	Node g = f.next;
1327	>	if (g != null) { // at least 2 nodes -- search and maybe resize
1328	>	for (Node e = g;;) {
1329	>	Object ek, ev;
1330	>	if ((e.hash & HASH_BITS) == h && (ev = e.val) != null &&
1331	>	((ek = e.key) == k || k.equals(ek)))
1332	>	return ev;
1333	>	if ((e = e.next) == null) {
1334	>	checkForResize();
1335	>	break;
1336	>	}
1337	>	}
1338	>	}
1339	>	if (((fh = f.hash) & LOCKED) != 0) {
1340	>	checkForResize();
1341	>	f.tryAwaitLock(tab, i);
1342	>	}
1343	>	else if (tabAt(tab, i) == f && f.casHash(fh, fh | LOCKED)) {
1344	>	Object oldVal = null;
1345	>	try {
1346	>	if (tabAt(tab, i) == f) {
1347	>	count = 1;
1348	>	for (Node e = f;; ++count) {
1349	>	Object ek, ev;
1350	>	if ((e.hash & HASH_BITS) == h &&
1351	>	(ev = e.val) != null &&
1352	>	((ek = e.key) == k || k.equals(ek))) {
1353		oldVal = ev;
1354	<	if ((e.val = v) == null) {
1355	<	deleted = true;
1356	<	Node en = e.next;
1357	<	if (pred != null)
1358	<	pred.next = en;
1359	<	else
1360	<	setTabAt(tab, i, en);
1361	<	}
1354	>	break;
1355	>	}
1356	>	Node last = e;
1357	>	if ((e = e.next) == null) {
1358	>	last.next = new Node(h, k, v, null);
1359	>	if (count >= TREE_THRESHOLD)
1360	>	replaceWithTreeBin(tab, i, k);
1361	>	break;
1362		}
622	–	break;
1363		}
1364	<	} while ((e = (pred = e).next) != null);
1364	>	}
1365	>	} finally {
1366	>	if (!f.casHash(fh | LOCKED, fh)) {
1367	>	f.hash = fh;
1368	>	synchronized (f) { f.notifyAll(); };
1369	>	}
1370	>	}
1371	>	if (count != 0) {
1372	>	if (oldVal != null)
1373	>	return oldVal;
1374	>	if (tab.length <= 64)
1375	>	count = 2;
1376	>	break;
1377		}
1378		}
1379	<	if (validated) {
1380	<	if (deleted)
1381	<	counter.decrement();
1382	<	return oldVal;
1379	>	}
1380	>	}
1381	>	counter.add(1L);
1382	>	if (count > 1)
1383	>	checkForResize();
1384	>	return null;
1385	>	}
1386	>
1387	>	/** Implementation for computeIfAbsent */
1388	>	private final Object internalComputeIfAbsent(K k,
1389	>	MappingFunction<? super K, ?> mf) {
1390	>	int h = spread(k.hashCode());
1391	>	Object val = null;
1392	>	int count = 0;
1393	>	for (Node[] tab = table;;) {
1394	>	Node f; int i, fh; Object fk, fv;
1395	>	if (tab == null)
1396	>	tab = initTable();
1397	>	else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
1398	>	Node node = new Node(fh = h | LOCKED, k, null, null);
1399	>	if (casTabAt(tab, i, null, node)) {
1400	>	count = 1;
1401	>	try {
1402	>	if ((val = mf.map(k)) != null)
1403	>	node.val = val;
1404	>	} finally {
1405	>	if (val == null)
1406	>	setTabAt(tab, i, null);
1407	>	if (!node.casHash(fh, h)) {
1408	>	node.hash = h;
1409	>	synchronized (node) { node.notifyAll(); };
1410	>	}
1411	>	}
1412	>	}
1413	>	if (count != 0)
1414	>	break;
1415	>	}
1416	>	else if ((fh = f.hash) == MOVED) {
1417	>	if ((fk = f.key) instanceof TreeBin) {
1418	>	TreeBin t = (TreeBin)fk;
1419	>	boolean added = false;
1420	>	t.acquire(0);
1421	>	try {
1422	>	if (tabAt(tab, i) == f) {
1423	>	count = 1;
1424	>	TreeNode p = t.getTreeNode(h, k, t.root);
1425	>	if (p != null)
1426	>	val = p.val;
1427	>	else if ((val = mf.map(k)) != null) {
1428	>	added = true;
1429	>	count = 2;
1430	>	t.putTreeNode(h, k, val);
1431	>	}
1432	>	}
1433	>	} finally {
1434	>	t.release(0);
1435	>	}
1436	>	if (count != 0) {
1437	>	if (!added)
1438	>	return val;
1439	>	break;
1440	>	}
1441	>	}
1442	>	else
1443	>	tab = (Node[])fk;
1444	>	}
1445	>	else if ((fh & HASH_BITS) == h && (fv = f.val) != null &&
1446	>	((fk = f.key) == k || k.equals(fk)))
1447	>	return fv;
1448	>	else {
1449	>	Node g = f.next;
1450	>	if (g != null) {
1451	>	for (Node e = g;;) {
1452	>	Object ek, ev;
1453	>	if ((e.hash & HASH_BITS) == h && (ev = e.val) != null &&
1454	>	((ek = e.key) == k || k.equals(ek)))
1455	>	return ev;
1456	>	if ((e = e.next) == null) {
1457	>	checkForResize();
1458	>	break;
1459	>	}
1460	>	}
1461	>	}
1462	>	if (((fh = f.hash) & LOCKED) != 0) {
1463	>	checkForResize();
1464	>	f.tryAwaitLock(tab, i);
1465	>	}
1466	>	else if (tabAt(tab, i) == f && f.casHash(fh, fh | LOCKED)) {
1467	>	boolean added = false;
1468	>	try {
1469	>	if (tabAt(tab, i) == f) {
1470	>	count = 1;
1471	>	for (Node e = f;; ++count) {
1472	>	Object ek, ev;
1473	>	if ((e.hash & HASH_BITS) == h &&
1474	>	(ev = e.val) != null &&
1475	>	((ek = e.key) == k || k.equals(ek))) {
1476	>	val = ev;
1477	>	break;
1478	>	}
1479	>	Node last = e;
1480	>	if ((e = e.next) == null) {
1481	>	if ((val = mf.map(k)) != null) {
1482	>	added = true;
1483	>	last.next = new Node(h, k, val, null);
1484	>	if (count >= TREE_THRESHOLD)
1485	>	replaceWithTreeBin(tab, i, k);
1486	>	}
1487	>	break;
1488	>	}
1489	>	}
1490	>	}
1491	>	} finally {
1492	>	if (!f.casHash(fh | LOCKED, fh)) {
1493	>	f.hash = fh;
1494	>	synchronized (f) { f.notifyAll(); };
1495	>	}
1496	>	}
1497	>	if (count != 0) {
1498	>	if (!added)
1499	>	return val;
1500	>	if (tab.length <= 64)
1501	>	count = 2;
1502	>	break;
1503	>	}
1504		}
1505		}
1506		}
1507	+	if (val == null)
1508	+	throw new NullPointerException();
1509	+	counter.add(1L);
1510	+	if (count > 1)
1511	+	checkForResize();
1512	+	return val;
1513		}
1514
1515	<	/** Implementation for computeIfAbsent and compute. Like put, but messier. */
1515	>	/** Implementation for compute */
1516		@SuppressWarnings("unchecked")
1517	<	private final V internalCompute(K k,
1518	<	MappingFunction<? super K, ? extends V> f,
640	<	boolean replace) {
1517	>	private final Object internalCompute(K k,
1518	>	RemappingFunction<? super K, V> mf) {
1519		int h = spread(k.hashCode());
1520	<	V val = null;
1520	>	Object val = null;
1521		boolean added = false;
1522	<	Node[] tab = table;
1523	<	outer:for (;;) {
1524	<	Node e; int i; Object ek, ev;
1522	>	int count = 0;
1523	>	for (Node[] tab = table;;) {
1524	>	Node f; int i, fh; Object fk;
1525		if (tab == null)
1526	<	tab = growTable();
1527	<	else if ((e = tabAt(tab, i = (tab.length - 1) & h)) == null) {
1528	<	Node node = new Node(h, k, null, null);
1529	<	boolean validated = false;
1530	<	synchronized (node) {  // must lock while computing value
1531	<	if (casTabAt(tab, i, null, node)) {
1532	<	validated = true;
1533	<	try {
1534	<	val = f.map(k);
1535	<	if (val != null) {
1536	<	node.val = val;
1537	<	added = true;
1538	<	}
1539	<	} finally {
1540	<	if (!added)
1541	<	setTabAt(tab, i, null);
1526	>	tab = initTable();
1527	>	else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
1528	>	Node node = new Node(fh = h | LOCKED, k, null, null);
1529	>	if (casTabAt(tab, i, null, node)) {
1530	>	try {
1531	>	count = 1;
1532	>	if ((val = mf.remap(k, null)) != null) {
1533	>	node.val = val;
1534	>	added = true;
1535	>	}
1536	>	} finally {
1537	>	if (!added)
1538	>	setTabAt(tab, i, null);
1539	>	if (!node.casHash(fh, h)) {
1540	>	node.hash = h;
1541	>	synchronized (node) { node.notifyAll(); };
1542		}
1543		}
1544		}
1545	<	if (validated)
1545	>	if (count != 0)
1546		break;
1547		}
1548	<	else if (e.hash < 0)
1549	<	tab = (Node[])e.key;
1550	<	else if (!replace && e.hash == h && (ev = e.val) != null &&
1551	<	((ek = e.key) == k || k.equals(ek))) {
1552	<	if (tabAt(tab, i) == e) {
1553	<	val = (V)ev;
1554	<	break;
1548	>	else if ((fh = f.hash) == MOVED) {
1549	>	if ((fk = f.key) instanceof TreeBin) {
1550	>	TreeBin t = (TreeBin)fk;
1551	>	t.acquire(0);
1552	>	try {
1553	>	if (tabAt(tab, i) == f) {
1554	>	count = 1;
1555	>	TreeNode p = t.getTreeNode(h, k, t.root);
1556	>	Object pv = (p == null) ? null : p.val;
1557	>	if ((val = mf.remap(k, (V)pv)) != null) {
1558	>	if (p != null)
1559	>	p.val = val;
1560	>	else {
1561	>	count = 2;
1562	>	added = true;
1563	>	t.putTreeNode(h, k, val);
1564	>	}
1565	>	}
1566	>	}
1567	>	} finally {
1568	>	t.release(0);
1569	>	}
1570	>	if (count != 0)
1571	>	break;
1572		}
1573	+	else
1574	+	tab = (Node[])fk;
1575		}
1576	<	else if (Thread.holdsLock(e))
1577	<	throw new IllegalStateException("Recursive map computation");
1578	<	else {
1579	<	boolean validated = false;
1580	<	boolean checkSize = false;
1581	<	synchronized (e) {
1582	<	if (tabAt(tab, i) == e) {
1583	<	validated = true;
1584	<	for (Node first = e;;) {
1585	<	if (e.hash == h &&
1586	<	((ek = e.key) == k || k.equals(ek)) &&
1587	<	((ev = e.val) != null)) {
1588	<	Object fv;
1589	<	if (replace && (fv = f.map(k)) != null)
1590	<	ev = e.val = fv;
1591	<	val = (V)ev;
1576	>	else if ((fh & LOCKED) != 0) {
1577	>	checkForResize();
1578	>	f.tryAwaitLock(tab, i);
1579	>	}
1580	>	else if (f.casHash(fh, fh | LOCKED)) {
1581	>	try {
1582	>	if (tabAt(tab, i) == f) {
1583	>	count = 1;
1584	>	for (Node e = f;; ++count) {
1585	>	Object ek, ev;
1586	>	if ((e.hash & HASH_BITS) == h &&
1587	>	(ev = e.val) != null &&
1588	>	((ek = e.key) == k || k.equals(ek))) {
1589	>	val = mf.remap(k, (V)ev);
1590	>	if (val != null)
1591	>	e.val = val;
1592		break;
1593		}
1594		Node last = e;
1595		if ((e = e.next) == null) {
1596	<	if ((val = f.map(k)) != null) {
1596	>	if ((val = mf.remap(k, null)) != null) {
1597		last.next = new Node(h, k, val, null);
1598		added = true;
1599	<	if (last != first || tab.length <= 64)
1600	<	checkSize = true;
1599	>	if (count >= TREE_THRESHOLD)
1600	>	replaceWithTreeBin(tab, i, k);
1601		}
1602		break;
1603		}
1604		}
1605		}
1606	+	} finally {
1607	+	if (!f.casHash(fh | LOCKED, fh)) {
1608	+	f.hash = fh;
1609	+	synchronized (f) { f.notifyAll(); };
1610	+	}
1611		}
1612	<	if (validated) {
1613	<	if (checkSize && tab.length < MAXIMUM_CAPACITY &&
1614	<	resizing == 0 && counter.sum() >= (long)threshold)
713	<	growTable();
1612	>	if (count != 0) {
1613	>	if (tab.length <= 64)
1614	>	count = 2;
1615		break;
1616		}
1617		}
1618		}
1619	<	if (added)
1620	<	counter.increment();
1619	>	if (val == null)
1620	>	throw new NullPointerException();
1621	>	if (added) {
1622	>	counter.add(1L);
1623	>	if (count > 1)
1624	>	checkForResize();
1625	>	}
1626		return val;
1627		}
1628
1629	+	/** Implementation for putAll */
1630	+	private final void internalPutAll(Map<?, ?> m) {
1631	+	tryPresize(m.size());
1632	+	long delta = 0L;     // number of uncommitted additions
1633	+	boolean npe = false; // to throw exception on exit for nulls
1634	+	try {                // to clean up counts on other exceptions
1635	+	for (Map.Entry<?, ?> entry : m.entrySet()) {
1636	+	Object k, v;
1637	+	if (entry == null || (k = entry.getKey()) == null ||
1638	+	(v = entry.getValue()) == null) {
1639	+	npe = true;
1640	+	break;
1641	+	}
1642	+	int h = spread(k.hashCode());
1643	+	for (Node[] tab = table;;) {
1644	+	int i; Node f; int fh; Object fk;
1645	+	if (tab == null)
1646	+	tab = initTable();
1647	+	else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null){
1648	+	if (casTabAt(tab, i, null, new Node(h, k, v, null))) {
1649	+	++delta;
1650	+	break;
1651	+	}
1652	+	}
1653	+	else if ((fh = f.hash) == MOVED) {
1654	+	if ((fk = f.key) instanceof TreeBin) {
1655	+	TreeBin t = (TreeBin)fk;
1656	+	boolean validated = false;
1657	+	t.acquire(0);
1658	+	try {
1659	+	if (tabAt(tab, i) == f) {
1660	+	validated = true;
1661	+	TreeNode p = t.getTreeNode(h, k, t.root);
1662	+	if (p != null)
1663	+	p.val = v;
1664	+	else {
1665	+	t.putTreeNode(h, k, v);
1666	+	++delta;
1667	+	}
1668	+	}
1669	+	} finally {
1670	+	t.release(0);
1671	+	}
1672	+	if (validated)
1673	+	break;
1674	+	}
1675	+	else
1676	+	tab = (Node[])fk;
1677	+	}
1678	+	else if ((fh & LOCKED) != 0) {
1679	+	counter.add(delta);
1680	+	delta = 0L;
1681	+	checkForResize();
1682	+	f.tryAwaitLock(tab, i);
1683	+	}
1684	+	else if (f.casHash(fh, fh | LOCKED)) {
1685	+	int count = 0;
1686	+	try {
1687	+	if (tabAt(tab, i) == f) {
1688	+	count = 1;
1689	+	for (Node e = f;; ++count) {
1690	+	Object ek, ev;
1691	+	if ((e.hash & HASH_BITS) == h &&
1692	+	(ev = e.val) != null &&
1693	+	((ek = e.key) == k || k.equals(ek))) {
1694	+	e.val = v;
1695	+	break;
1696	+	}
1697	+	Node last = e;
1698	+	if ((e = e.next) == null) {
1699	+	++delta;
1700	+	last.next = new Node(h, k, v, null);
1701	+	if (count >= TREE_THRESHOLD)
1702	+	replaceWithTreeBin(tab, i, k);
1703	+	break;
1704	+	}
1705	+	}
1706	+	}
1707	+	} finally {
1708	+	if (!f.casHash(fh | LOCKED, fh)) {
1709	+	f.hash = fh;
1710	+	synchronized (f) { f.notifyAll(); };
1711	+	}
1712	+	}
1713	+	if (count != 0) {
1714	+	if (count > 1) {
1715	+	counter.add(delta);
1716	+	delta = 0L;
1717	+	checkForResize();
1718	+	}
1719	+	break;
1720	+	}
1721	+	}
1722	+	}
1723	+	}
1724	+	} finally {
1725	+	if (delta != 0)
1726	+	counter.add(delta);
1727	+	}
1728	+	if (npe)
1729	+	throw new NullPointerException();
1730	+	}
1731	+
1732	+	/* ---------------- Table Initialization and Resizing -------------- */
1733	+
1734	+	/**
1735	+	* Returns a power of two table size for the given desired capacity.
1736	+	* See Hackers Delight, sec 3.2
1737	+	*/
1738	+	private static final int tableSizeFor(int c) {
1739	+	int n = c - 1;
1740	+	n |= n >>> 1;
1741	+	n |= n >>> 2;
1742	+	n |= n >>> 4;
1743	+	n |= n >>> 8;
1744	+	n |= n >>> 16;
1745	+	return (n < 0) ? 1 : (n >= MAXIMUM_CAPACITY) ? MAXIMUM_CAPACITY : n + 1;
1746	+	}
1747	+
1748	+	/**
1749	+	* Initializes table, using the size recorded in sizeCtl.
1750	+	*/
1751	+	private final Node[] initTable() {
1752	+	Node[] tab; int sc;
1753	+	while ((tab = table) == null) {
1754	+	if ((sc = sizeCtl) < 0)
1755	+	Thread.yield(); // lost initialization race; just spin
1756	+	else if (UNSAFE.compareAndSwapInt(this, sizeCtlOffset, sc, -1)) {
1757	+	try {
1758	+	if ((tab = table) == null) {
1759	+	int n = (sc > 0) ? sc : DEFAULT_CAPACITY;
1760	+	tab = table = new Node[n];
1761	+	sc = n - (n >>> 2);
1762	+	}
1763	+	} finally {
1764	+	sizeCtl = sc;
1765	+	}
1766	+	break;
1767	+	}
1768	+	}
1769	+	return tab;
1770	+	}
1771	+
1772	+	/**
1773	+	* If table is too small and not already resizing, creates next
1774	+	* table and transfers bins.  Rechecks occupancy after a transfer
1775	+	* to see if another resize is already needed because resizings
1776	+	* are lagging additions.
1777	+	*/
1778	+	private final void checkForResize() {
1779	+	Node[] tab; int n, sc;
1780	+	while ((tab = table) != null &&
1781	+	(n = tab.length) < MAXIMUM_CAPACITY &&
1782	+	(sc = sizeCtl) >= 0 && counter.sum() >= (long)sc &&
1783	+	UNSAFE.compareAndSwapInt(this, sizeCtlOffset, sc, -1)) {
1784	+	try {
1785	+	if (tab == table) {
1786	+	table = rebuild(tab);
1787	+	sc = (n << 1) - (n >>> 1);
1788	+	}
1789	+	} finally {
1790	+	sizeCtl = sc;
1791	+	}
1792	+	}
1793	+	}
1794	+
1795	+	/**
1796	+	* Tries to presize table to accommodate the given number of elements.
1797	+	*
1798	+	* @param size number of elements (doesn't need to be perfectly accurate)
1799	+	*/
1800	+	private final void tryPresize(int size) {
1801	+	int c = (size >= (MAXIMUM_CAPACITY >>> 1)) ? MAXIMUM_CAPACITY :
1802	+	tableSizeFor(size + (size >>> 1) + 1);
1803	+	int sc;
1804	+	while ((sc = sizeCtl) >= 0) {
1805	+	Node[] tab = table; int n;
1806	+	if (tab == null || (n = tab.length) == 0) {
1807	+	n = (sc > c) ? sc : c;
1808	+	if (UNSAFE.compareAndSwapInt(this, sizeCtlOffset, sc, -1)) {
1809	+	try {
1810	+	if (table == tab) {
1811	+	table = new Node[n];
1812	+	sc = n - (n >>> 2);
1813	+	}
1814	+	} finally {
1815	+	sizeCtl = sc;
1816	+	}
1817	+	}
1818	+	}
1819	+	else if (c <= sc || n >= MAXIMUM_CAPACITY)
1820	+	break;
1821	+	else if (UNSAFE.compareAndSwapInt(this, sizeCtlOffset, sc, -1)) {
1822	+	try {
1823	+	if (table == tab) {
1824	+	table = rebuild(tab);
1825	+	sc = (n << 1) - (n >>> 1);
1826	+	}
1827	+	} finally {
1828	+	sizeCtl = sc;
1829	+	}
1830	+	}
1831	+	}
1832	+	}
1833	+
1834	+	/*
1835	+	* Moves and/or copies the nodes in each bin to new table. See
1836	+	* above for explanation.
1837	+	*
1838	+	* @return the new table
1839	+	*/
1840	+	private static final Node[] rebuild(Node[] tab) {
1841	+	int n = tab.length;
1842	+	Node[] nextTab = new Node[n << 1];
1843	+	Node fwd = new Node(MOVED, nextTab, null, null);
1844	+	int[] buffer = null;       // holds bins to revisit; null until needed
1845	+	Node rev = null;           // reverse forwarder; null until needed
1846	+	int nbuffered = 0;         // the number of bins in buffer list
1847	+	int bufferIndex = 0;       // buffer index of current buffered bin
1848	+	int bin = n - 1;           // current non-buffered bin or -1 if none
1849	+
1850	+	for (int i = bin;;) {      // start upwards sweep
1851	+	int fh; Node f;
1852	+	if ((f = tabAt(tab, i)) == null) {
1853	+	if (bin >= 0) {    // no lock needed (or available)
1854	+	if (!casTabAt(tab, i, f, fwd))
1855	+	continue;
1856	+	}
1857	+	else {             // transiently use a locked forwarding node
1858	+	Node g = new Node(MOVED|LOCKED, nextTab, null, null);
1859	+	if (!casTabAt(tab, i, f, g))
1860	+	continue;
1861	+	setTabAt(nextTab, i, null);
1862	+	setTabAt(nextTab, i + n, null);
1863	+	setTabAt(tab, i, fwd);
1864	+	if (!g.casHash(MOVED|LOCKED, MOVED)) {
1865	+	g.hash = MOVED;
1866	+	synchronized (g) { g.notifyAll(); }
1867	+	}
1868	+	}
1869	+	}
1870	+	else if ((fh = f.hash) == MOVED) {
1871	+	Object fk = f.key;
1872	+	if (fk instanceof TreeBin) {
1873	+	TreeBin t = (TreeBin)fk;
1874	+	boolean validated = false;
1875	+	t.acquire(0);
1876	+	try {
1877	+	if (tabAt(tab, i) == f) {
1878	+	validated = true;
1879	+	splitTreeBin(nextTab, i, t);
1880	+	setTabAt(tab, i, fwd);
1881	+	}
1882	+	} finally {
1883	+	t.release(0);
1884	+	}
1885	+	if (!validated)
1886	+	continue;
1887	+	}
1888	+	}
1889	+	else if ((fh & LOCKED) == 0 && f.casHash(fh, fh|LOCKED)) {
1890	+	boolean validated = false;
1891	+	try {              // split to lo and hi lists; copying as needed
1892	+	if (tabAt(tab, i) == f) {
1893	+	validated = true;
1894	+	splitBin(nextTab, i, f);
1895	+	setTabAt(tab, i, fwd);
1896	+	}
1897	+	} finally {
1898	+	if (!f.casHash(fh | LOCKED, fh)) {
1899	+	f.hash = fh;
1900	+	synchronized (f) { f.notifyAll(); };
1901	+	}
1902	+	}
1903	+	if (!validated)
1904	+	continue;
1905	+	}
1906	+	else {
1907	+	if (buffer == null) // initialize buffer for revisits
1908	+	buffer = new int[TRANSFER_BUFFER_SIZE];
1909	+	if (bin < 0 && bufferIndex > 0) {
1910	+	int j = buffer[--bufferIndex];
1911	+	buffer[bufferIndex] = i;
1912	+	i = j;         // swap with another bin
1913	+	continue;
1914	+	}
1915	+	if (bin < 0 || nbuffered >= TRANSFER_BUFFER_SIZE) {
1916	+	f.tryAwaitLock(tab, i);
1917	+	continue;      // no other options -- block
1918	+	}
1919	+	if (rev == null)   // initialize reverse-forwarder
1920	+	rev = new Node(MOVED, tab, null, null);
1921	+	if (tabAt(tab, i) != f || (f.hash & LOCKED) == 0)
1922	+	continue;      // recheck before adding to list
1923	+	buffer[nbuffered++] = i;
1924	+	setTabAt(nextTab, i, rev);     // install place-holders
1925	+	setTabAt(nextTab, i + n, rev);
1926	+	}
1927	+
1928	+	if (bin > 0)
1929	+	i = --bin;
1930	+	else if (buffer != null && nbuffered > 0) {
1931	+	bin = -1;
1932	+	i = buffer[bufferIndex = --nbuffered];
1933	+	}
1934	+	else
1935	+	return nextTab;
1936	+	}
1937	+	}
1938	+
1939	+	/**
1940	+	* Split a normal bin with list headed by e into lo and hi parts;
1941	+	* install in given table
1942	+	*/
1943	+	private static void splitBin(Node[] nextTab, int i, Node e) {
1944	+	int bit = nextTab.length >>> 1; // bit to split on
1945	+	int runBit = e.hash & bit;
1946	+	Node lastRun = e, lo = null, hi = null;
1947	+	for (Node p = e.next; p != null; p = p.next) {
1948	+	int b = p.hash & bit;
1949	+	if (b != runBit) {
1950	+	runBit = b;
1951	+	lastRun = p;
1952	+	}
1953	+	}
1954	+	if (runBit == 0)
1955	+	lo = lastRun;
1956	+	else
1957	+	hi = lastRun;
1958	+	for (Node p = e; p != lastRun; p = p.next) {
1959	+	int ph = p.hash & HASH_BITS;
1960	+	Object pk = p.key, pv = p.val;
1961	+	if ((ph & bit) == 0)
1962	+	lo = new Node(ph, pk, pv, lo);
1963	+	else
1964	+	hi = new Node(ph, pk, pv, hi);
1965	+	}
1966	+	setTabAt(nextTab, i, lo);
1967	+	setTabAt(nextTab, i + bit, hi);
1968	+	}
1969	+
1970		/**
1971	<	* Implementation for clear. Steps through each bin, removing all nodes.
1971	>	* Split a tree bin into lo and hi parts; install in given table
1972	>	*/
1973	>	private static void splitTreeBin(Node[] nextTab, int i, TreeBin t) {
1974	>	int bit = nextTab.length >>> 1;
1975	>	TreeBin lt = new TreeBin();
1976	>	TreeBin ht = new TreeBin();
1977	>	int lc = 0, hc = 0;
1978	>	for (Node e = t.first; e != null; e = e.next) {
1979	>	int h = e.hash & HASH_BITS;
1980	>	Object k = e.key, v = e.val;
1981	>	if ((h & bit) == 0) {
1982	>	++lc;
1983	>	lt.putTreeNode(h, k, v);
1984	>	}
1985	>	else {
1986	>	++hc;
1987	>	ht.putTreeNode(h, k, v);
1988	>	}
1989	>	}
1990	>	Node ln, hn; // throw away trees if too small
1991	>	if (lc <= (TREE_THRESHOLD >>> 1)) {
1992	>	ln = null;
1993	>	for (Node p = lt.first; p != null; p = p.next)
1994	>	ln = new Node(p.hash, p.key, p.val, ln);
1995	>	}
1996	>	else
1997	>	ln = new Node(MOVED, lt, null, null);
1998	>	setTabAt(nextTab, i, ln);
1999	>	if (hc <= (TREE_THRESHOLD >>> 1)) {
2000	>	hn = null;
2001	>	for (Node p = ht.first; p != null; p = p.next)
2002	>	hn = new Node(p.hash, p.key, p.val, hn);
2003	>	}
2004	>	else
2005	>	hn = new Node(MOVED, ht, null, null);
2006	>	setTabAt(nextTab, i + bit, hn);
2007	>	}
2008	>
2009	>	/**
2010	>	* Implementation for clear. Steps through each bin, removing all
2011	>	* nodes.
2012		*/
2013		private final void internalClear() {
2014		long delta = 0L; // negative number of deletions
2015		int i = 0;
2016		Node[] tab = table;
2017		while (tab != null && i < tab.length) {
2018	<	Node e = tabAt(tab, i);
2019	<	if (e == null)
2018	>	int fh; Object fk;
2019	>	Node f = tabAt(tab, i);
2020	>	if (f == null)
2021		++i;
2022	<	else if (e.hash < 0)
2023	<	tab = (Node[])e.key;
2024	<	else {
2025	<	boolean validated = false;
2026	<	synchronized (e) {
2027	<	if (tabAt(tab, i) == e) {
2028	<	validated = true;
2029	<	Node en;
742	<	do {
743	<	en = e.next;
744	<	if (e.val != null) { // currently always true
745	<	e.val = null;
2022	>	else if ((fh = f.hash) == MOVED) {
2023	>	if ((fk = f.key) instanceof TreeBin) {
2024	>	TreeBin t = (TreeBin)fk;
2025	>	t.acquire(0);
2026	>	try {
2027	>	if (tabAt(tab, i) == f) {
2028	>	for (Node p = t.first; p != null; p = p.next) {
2029	>	p.val = null;
2030		--delta;
2031		}
2032	<	} while ((e = en) != null);
2032	>	t.first = null;
2033	>	t.root = null;
2034	>	++i;
2035	>	}
2036	>	} finally {
2037	>	t.release(0);
2038	>	}
2039	>	}
2040	>	else
2041	>	tab = (Node[])fk;
2042	>	}
2043	>	else if ((fh & LOCKED) != 0) {
2044	>	counter.add(delta); // opportunistically update count
2045	>	delta = 0L;
2046	>	f.tryAwaitLock(tab, i);
2047	>	}
2048	>	else if (f.casHash(fh, fh | LOCKED)) {
2049	>	try {
2050	>	if (tabAt(tab, i) == f) {
2051	>	for (Node e = f; e != null; e = e.next) {
2052	>	e.val = null;
2053	>	--delta;
2054	>	}
2055		setTabAt(tab, i, null);
2056	+	++i;
2057	+	}
2058	+	} finally {
2059	+	if (!f.casHash(fh | LOCKED, fh)) {
2060	+	f.hash = fh;
2061	+	synchronized (f) { f.notifyAll(); };
2062		}
2063		}
752	–	if (validated)
753	–	++i;
2064		}
2065		}
2066	<	counter.add(delta);
2066	>	if (delta != 0)
2067	>	counter.add(delta);
2068		}
2069
2070		/* ----------------Table Traversal -------------- */
#	Line 764 | Line 2075 | public class ConcurrentHashMapV8<K, V>
2075		*
2076		* At each step, the iterator snapshots the key ("nextKey") and
2077		* value ("nextVal") of a valid node (i.e., one that, at point of
2078	<	* snapshot, has a nonnull user value). Because val fields can
2078	>	* snapshot, has a non-null user value). Because val fields can
2079		* change (including to null, indicating deletion), field nextVal
2080		* might not be accurate at point of use, but still maintains the
2081		* weak consistency property of holding a value that was once
#	Line 777 | Line 2088 | public class ConcurrentHashMapV8<K, V>
2088		* value, or key-value pairs as return values of Iterator.next(),
2089		* and encapsulate the it.next check as hasNext();
2090		*
2091	<	* The iterator visits each valid node that was reachable upon
2092	<	* iterator construction once. It might miss some that were added
2093	<	* to a bin after the bin was visited, which is OK wrt consistency
2094	<	* guarantees. Maintaining this property in the face of possible
2095	<	* ongoing resizes requires a fair amount of bookkeeping state
2096	<	* that is difficult to optimize away amidst volatile accesses.
2097	<	* Even so, traversal maintains reasonable throughput.
2091	>	* The iterator visits once each still-valid node that was
2092	>	* reachable upon iterator construction. It might miss some that
2093	>	* were added to a bin after the bin was visited, which is OK wrt
2094	>	* consistency guarantees. Maintaining this property in the face
2095	>	* of possible ongoing resizes requires a fair amount of
2096	>	* bookkeeping state that is difficult to optimize away amidst
2097	>	* volatile accesses.  Even so, traversal maintains reasonable
2098	>	* throughput.
2099		*
2100		* Normally, iteration proceeds bin-by-bin traversing lists.
2101		* However, if the table has been resized, then all future steps
#	Line 821 | Line 2133 | public class ConcurrentHashMapV8<K, V>
2133		this.tab = tab;
2134		baseSize = (tab == null) ? 0 : tab.length;
2135		baseLimit = (hi <= baseSize) ? hi : baseSize;
2136	<	index = baseIndex = lo;
2136	>	index = baseIndex = (lo >= 0) ? lo : 0;
2137		next = null;
2138		advance();
2139		}
#	Line 830 | Line 2142 | public class ConcurrentHashMapV8<K, V>
2142		final void advance() {
2143		Node e = last = next;
2144		outer: do {
2145	<	if (e != null)                   // pass used or skipped node
2145	>	if (e != null)                  // advance past used/skipped node
2146		e = e.next;
2147	<	while (e == null) {              // get to next non-null bin
2148	<	Node[] t; int b, i, n;       // checks must use locals
2147	>	while (e == null) {             // get to next non-null bin
2148	>	Node[] t; int b, i, n; Object ek; // checks must use locals
2149		if ((b = baseIndex) >= baseLimit || (i = index) < 0 ||
2150		(t = tab) == null || i >= (n = t.length))
2151		break outer;
2152	<	else if ((e = tabAt(t, i)) != null && e.hash < 0)
2153	<	tab = (Node[])e.key;     // restarts due to null val
2154	<	else                         // visit upper slots if present
2155	<	index = (i += baseSize) < n ? i : (baseIndex = b + 1);
2152	>	else if ((e = tabAt(t, i)) != null && e.hash == MOVED) {
2153	>	if ((ek = e.key) instanceof TreeBin)
2154	>	e = ((TreeBin)ek).first;
2155	>	else {
2156	>	tab = (Node[])ek;
2157	>	continue;           // restarts due to null val
2158	>	}
2159	>	}                           // visit upper slots if present
2160	>	index = (i += baseSize) < n ? i : (baseIndex = b + 1);
2161		}
2162		nextKey = e.key;
2163	<	} while ((nextVal = e.val) == null); // skip deleted or special nodes
2163	>	} while ((nextVal = e.val) == null);// skip deleted or special nodes
2164		next = e;
2165		}
2166		}
#	Line 855 | Line 2172 | public class ConcurrentHashMapV8<K, V>
2172		*/
2173		public ConcurrentHashMapV8() {
2174		this.counter = new LongAdder();
858	–	this.targetCapacity = DEFAULT_CAPACITY;
2175		}
2176
2177		/**
#	Line 875 | Line 2191 | public class ConcurrentHashMapV8<K, V>
2191		MAXIMUM_CAPACITY :
2192		tableSizeFor(initialCapacity + (initialCapacity >>> 1) + 1));
2193		this.counter = new LongAdder();
2194	<	this.targetCapacity = cap;
2194	>	this.sizeCtl = cap;
2195		}
2196
2197		/**
#	Line 885 | Line 2201 | public class ConcurrentHashMapV8<K, V>
2201		*/
2202		public ConcurrentHashMapV8(Map<? extends K, ? extends V> m) {
2203		this.counter = new LongAdder();
2204	<	this.targetCapacity = DEFAULT_CAPACITY;
2205	<	putAll(m);
2204	>	this.sizeCtl = DEFAULT_CAPACITY;
2205	>	internalPutAll(m);
2206		}
2207
2208		/**
#	Line 933 | Line 2249 | public class ConcurrentHashMapV8<K, V>
2249		if (initialCapacity < concurrencyLevel)   // Use at least as many bins
2250		initialCapacity = concurrencyLevel;   // as estimated threads
2251		long size = (long)(1.0 + (long)initialCapacity / loadFactor);
2252	<	int cap =  ((size >= (long)MAXIMUM_CAPACITY) ?
2253	<	MAXIMUM_CAPACITY: tableSizeFor((int)size));
2252	>	int cap = ((size >= (long)MAXIMUM_CAPACITY) ?
2253	>	MAXIMUM_CAPACITY: tableSizeFor((int)size));
2254		this.counter = new LongAdder();
2255	<	this.targetCapacity = cap;
2255	>	this.sizeCtl = cap;
2256		}
2257
2258		/**
#	Line 956 | Line 2272 | public class ConcurrentHashMapV8<K, V>
2272		(int)n);
2273		}
2274
2275	+	final long longSize() { // accurate version of size needed for views
2276	+	long n = counter.sum();
2277	+	return (n < 0L) ? 0L : n;
2278	+	}
2279	+
2280		/**
2281		* Returns the value to which the specified key is mapped,
2282		* or {@code null} if this map contains no mapping for the key.
#	Line 1048 | Line 2369 | public class ConcurrentHashMapV8<K, V>
2369		public V put(K key, V value) {
2370		if (key == null || value == null)
2371		throw new NullPointerException();
2372	<	return (V)internalPut(key, value, true);
2372	>	return (V)internalPut(key, value);
2373		}
2374
2375		/**
#	Line 1062 | Line 2383 | public class ConcurrentHashMapV8<K, V>
2383		public V putIfAbsent(K key, V value) {
2384		if (key == null || value == null)
2385		throw new NullPointerException();
2386	<	return (V)internalPut(key, value, false);
2386	>	return (V)internalPutIfAbsent(key, value);
2387		}
2388
2389		/**
#	Line 1073 | Line 2394 | public class ConcurrentHashMapV8<K, V>
2394		* @param m mappings to be stored in this map
2395		*/
2396		public void putAll(Map<? extends K, ? extends V> m) {
2397	<	if (m == null)
1077	<	throw new NullPointerException();
1078	<	/*
1079	<	* If uninitialized, try to adjust targetCapacity to
1080	<	* accommodate the given number of elements.
1081	<	*/
1082	<	if (table == null) {
1083	<	int size = m.size();
1084	<	int cap = (size >= (MAXIMUM_CAPACITY >>> 1)) ? MAXIMUM_CAPACITY :
1085	<	tableSizeFor(size + (size >>> 1) + 1);
1086	<	if (cap > targetCapacity)
1087	<	targetCapacity = cap;
1088	<	}
1089	<	for (Map.Entry<? extends K, ? extends V> e : m.entrySet())
1090	<	put(e.getKey(), e.getValue());
2397	>	internalPutAll(m);
2398		}
2399
2400		/**
2401		* If the specified key is not already associated with a value,
2402	<	* computes its value using the given mappingFunction, and if
2403	<	* non-null, enters it into the map.  This is equivalent to
2404	<	*  <pre> {@code
2402	>	* computes its value using the given mappingFunction and
2403	>	* enters it into the map.  This is equivalent to
2404	>	* <pre> {@code
2405		* if (map.containsKey(key))
2406		*   return map.get(key);
2407		* value = mappingFunction.map(key);
2408	<	* if (value != null)
1102	<	*   map.put(key, value);
2408	>	* map.put(key, value);
2409		* return value;}</pre>
2410		*
2411	<	* except that the action is performed atomically.  Some attempted
2412	<	* update operations on this map by other threads may be blocked
2413	<	* while computation is in progress, so the computation should be
2414	<	* short and simple, and must not attempt to update any other
2415	<	* mappings of this Map. The most appropriate usage is to
2416	<	* construct a new object serving as an initial mapped value, or
2417	<	* memoized result, as in:
2411	>	* except that the action is performed atomically.  If the
2412	>	* function returns {@code null} (in which case a {@code
2413	>	* NullPointerException} is thrown), or the function itself throws
2414	>	* an (unchecked) exception, the exception is rethrown to its
2415	>	* caller, and no mapping is recorded.  Some attempted update
2416	>	* operations on this map by other threads may be blocked while
2417	>	* computation is in progress, so the computation should be short
2418	>	* and simple, and must not attempt to update any other mappings
2419	>	* of this Map. The most appropriate usage is to construct a new
2420	>	* object serving as an initial mapped value, or memoized result,
2421	>	* as in:
2422	>	*
2423		*  <pre> {@code
2424		* map.computeIfAbsent(key, new MappingFunction<K, V>() {
2425		*   public V map(K k) { return new Value(f(k)); }});}</pre>
#	Line 1116 | Line 2427 | public class ConcurrentHashMapV8<K, V>
2427		* @param key key with which the specified value is to be associated
2428		* @param mappingFunction the function to compute a value
2429		* @return the current (existing or computed) value associated with
2430	<	*         the specified key, or {@code null} if the computation
2431	<	*         returned {@code null}
2432	<	* @throws NullPointerException if the specified key or mappingFunction
1122	<	*         is null
2430	>	*         the specified key.
2431	>	* @throws NullPointerException if the specified key, mappingFunction,
2432	>	*         or computed value is null
2433		* @throws IllegalStateException if the computation detectably
2434		*         attempts a recursive update to this map that would
2435		*         otherwise never complete
2436		* @throws RuntimeException or Error if the mappingFunction does so,
2437		*         in which case the mapping is left unestablished
2438		*/
2439	+	@SuppressWarnings("unchecked")
2440		public V computeIfAbsent(K key, MappingFunction<? super K, ? extends V> mappingFunction) {
2441		if (key == null || mappingFunction == null)
2442		throw new NullPointerException();
2443	<	return internalCompute(key, mappingFunction, false);
2443	>	return (V)internalComputeIfAbsent(key, mappingFunction);
2444		}
2445
2446		/**
2447	<	* Computes the value associated with the given key using the given
2448	<	* mappingFunction, and if non-null, enters it into the map.  This
2449	<	* is equivalent to
2447	>	* Computes and enters a new mapping value given a key and
2448	>	* its current mapped value (or {@code null} if there is no current
2449	>	* mapping). This is equivalent to
2450		*  <pre> {@code
2451	<	* value = mappingFunction.map(key);
2452	<	* if (value != null)
1142	<	*   map.put(key, value);
1143	<	* else
1144	<	*   value = map.get(key);
1145	<	* return value;}</pre>
2451	>	*  map.put(key, remappingFunction.remap(key, map.get(key));
2452	>	* }</pre>
2453		*
2454	<	* except that the action is performed atomically.  Some attempted
2454	>	* except that the action is performed atomically.  If the
2455	>	* function returns {@code null} (in which case a {@code
2456	>	* NullPointerException} is thrown), or the function itself throws
2457	>	* an (unchecked) exception, the exception is rethrown to its
2458	>	* caller, and current mapping is left unchanged.  Some attempted
2459		* update operations on this map by other threads may be blocked
2460		* while computation is in progress, so the computation should be
2461		* short and simple, and must not attempt to update any other
2462	<	* mappings of this Map.
2462	>	* mappings of this Map. For example, to either create or
2463	>	* append new messages to a value mapping:
2464	>	*
2465	>	* <pre> {@code
2466	>	* Map<Key, String> map = ...;
2467	>	* final String msg = ...;
2468	>	* map.compute(key, new RemappingFunction<Key, String>() {
2469	>	*   public String remap(Key k, String v) {
2470	>	*    return (v == null) ? msg : v + msg;});}}</pre>
2471		*
2472		* @param key key with which the specified value is to be associated
2473	<	* @param mappingFunction the function to compute a value
2474	<	* @return the current value associated with
2475	<	*         the specified key, or {@code null} if the computation
2476	<	*         returned {@code null} and the value was not otherwise present
2477	<	* @throws NullPointerException if the specified key or mappingFunction
1159	<	*         is null
2473	>	* @param remappingFunction the function to compute a value
2474	>	* @return the new value associated with
2475	>	*         the specified key.
2476	>	* @throws NullPointerException if the specified key or remappingFunction
2477	>	*         or computed value is null
2478		* @throws IllegalStateException if the computation detectably
2479		*         attempts a recursive update to this map that would
2480		*         otherwise never complete
2481	<	* @throws RuntimeException or Error if the mappingFunction does so,
2481	>	* @throws RuntimeException or Error if the remappingFunction does so,
2482		*         in which case the mapping is unchanged
2483		*/
2484	<	public V compute(K key, MappingFunction<? super K, ? extends V> mappingFunction) {
2485	<	if (key == null || mappingFunction == null)
2484	>	@SuppressWarnings("unchecked")
2485	>	public V compute(K key, RemappingFunction<? super K, V> remappingFunction) {
2486	>	if (key == null || remappingFunction == null)
2487		throw new NullPointerException();
2488	<	return internalCompute(key, mappingFunction, true);
2488	>	return (V)internalCompute(key, remappingFunction);
2489		}
2490
2491		/**
#	Line 1462 | Line 2781 | public class ConcurrentHashMapV8<K, V>
2781		Object k = nextKey;
2782		Object v = nextVal;
2783		advance();
2784	<	return new WriteThroughEntry<K,V>(map, (K)k, (V)v);
2784	>	return new WriteThroughEntry<K,V>((K)k, (V)v, map);
2785	>	}
2786	>	}
2787	>
2788	>	static final class SnapshotEntryIterator<K,V> extends ViewIterator<K,V>
2789	>	implements Iterator<Map.Entry<K,V>> {
2790	>	SnapshotEntryIterator(ConcurrentHashMapV8<K, V> map) { super(map); }
2791	>
2792	>	@SuppressWarnings("unchecked")
2793	>	public final Map.Entry<K,V> next() {
2794	>	if (next == null)
2795	>	throw new NoSuchElementException();
2796	>	Object k = nextKey;
2797	>	Object v = nextVal;
2798	>	advance();
2799	>	return new SnapshotEntry<K,V>((K)k, (V)v);
2800		}
2801		}
2802
2803		/**
2804	<	* Custom Entry class used by EntryIterator.next(), that relays
1471	<	* setValue changes to the underlying map.
2804	>	* Base of writeThrough and Snapshot entry classes
2805		*/
2806	<	static final class WriteThroughEntry<K,V> implements Map.Entry<K, V> {
1474	<	final ConcurrentHashMapV8<K, V> map;
2806	>	static abstract class MapEntry<K,V> implements Map.Entry<K, V> {
2807		final K key; // non-null
2808		V val;       // non-null
2809	<	WriteThroughEntry(ConcurrentHashMapV8<K, V> map, K key, V val) {
1478	<	this.map = map; this.key = key; this.val = val;
1479	<	}
1480	<
2809	>	MapEntry(K key, V val)        { this.key = key; this.val = val; }
2810		public final K getKey()       { return key; }
2811		public final V getValue()     { return val; }
2812		public final int hashCode()   { return key.hashCode() ^ val.hashCode(); }
#	Line 1492 | Line 2821 | public class ConcurrentHashMapV8<K, V>
2821		(v == val || v.equals(val)));
2822		}
2823
2824	+	public abstract V setValue(V value);
2825	+	}
2826	+
2827	+	/**
2828	+	* Entry used by EntryIterator.next(), that relays setValue
2829	+	* changes to the underlying map.
2830	+	*/
2831	+	static final class WriteThroughEntry<K,V> extends MapEntry<K,V>
2832	+	implements Map.Entry<K, V> {
2833	+	final ConcurrentHashMapV8<K, V> map;
2834	+	WriteThroughEntry(K key, V val, ConcurrentHashMapV8<K, V> map) {
2835	+	super(key, val);
2836	+	this.map = map;
2837	+	}
2838	+
2839		/**
2840		* Sets our entry's value and writes through to the map. The
2841		* value to return is somewhat arbitrary here. Since a
#	Line 1510 | Line 2854 | public class ConcurrentHashMapV8<K, V>
2854		}
2855		}
2856
2857	+	/**
2858	+	* Internal version of entry, that doesn't write though changes
2859	+	*/
2860	+	static final class SnapshotEntry<K,V> extends MapEntry<K,V>
2861	+	implements Map.Entry<K, V> {
2862	+	SnapshotEntry(K key, V val) { super(key, val); }
2863	+	public final V setValue(V value) { // only locally update
2864	+	if (value == null) throw new NullPointerException();
2865	+	V v = val;
2866	+	val = value;
2867	+	return v;
2868	+	}
2869	+	}
2870	+
2871		/* ----------------Views -------------- */
2872
2873	<	/*
2874	<	* These currently just extend java.util.AbstractX classes, but
2875	<	* may need a new custom base to support partitioned traversal.
2873	>	/**
2874	>	* Base class for views. This is done mainly to allow adding
2875	>	* customized parallel traversals (not yet implemented.)
2876		*/
2877	<
1520	<	static final class KeySet<K,V> extends AbstractSet<K> {
2877	>	static abstract class MapView<K, V> {
2878		final ConcurrentHashMapV8<K, V> map;
2879	<	KeySet(ConcurrentHashMapV8<K, V> map)   { this.map = map; }
1523	<
2879	>	MapView(ConcurrentHashMapV8<K, V> map)  { this.map = map; }
2880		public final int size()                 { return map.size(); }
2881		public final boolean isEmpty()          { return map.isEmpty(); }
2882		public final void clear()               { map.clear(); }
2883	+
2884	+	// implementations below rely on concrete classes supplying these
2885	+	abstract Iterator<?> iter();
2886	+	abstract public boolean contains(Object o);
2887	+	abstract public boolean remove(Object o);
2888	+
2889	+	private static final String oomeMsg = "Required array size too large";
2890	+
2891	+	public final Object[] toArray() {
2892	+	long sz = map.longSize();
2893	+	if (sz > (long)(MAX_ARRAY_SIZE))
2894	+	throw new OutOfMemoryError(oomeMsg);
2895	+	int n = (int)sz;
2896	+	Object[] r = new Object[n];
2897	+	int i = 0;
2898	+	Iterator<?> it = iter();
2899	+	while (it.hasNext()) {
2900	+	if (i == n) {
2901	+	if (n >= MAX_ARRAY_SIZE)
2902	+	throw new OutOfMemoryError(oomeMsg);
2903	+	if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1)
2904	+	n = MAX_ARRAY_SIZE;
2905	+	else
2906	+	n += (n >>> 1) + 1;
2907	+	r = Arrays.copyOf(r, n);
2908	+	}
2909	+	r[i++] = it.next();
2910	+	}
2911	+	return (i == n) ? r : Arrays.copyOf(r, i);
2912	+	}
2913	+
2914	+	@SuppressWarnings("unchecked")
2915	+	public final <T> T[] toArray(T[] a) {
2916	+	long sz = map.longSize();
2917	+	if (sz > (long)(MAX_ARRAY_SIZE))
2918	+	throw new OutOfMemoryError(oomeMsg);
2919	+	int m = (int)sz;
2920	+	T[] r = (a.length >= m) ? a :
2921	+	(T[])java.lang.reflect.Array
2922	+	.newInstance(a.getClass().getComponentType(), m);
2923	+	int n = r.length;
2924	+	int i = 0;
2925	+	Iterator<?> it = iter();
2926	+	while (it.hasNext()) {
2927	+	if (i == n) {
2928	+	if (n >= MAX_ARRAY_SIZE)
2929	+	throw new OutOfMemoryError(oomeMsg);
2930	+	if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1)
2931	+	n = MAX_ARRAY_SIZE;
2932	+	else
2933	+	n += (n >>> 1) + 1;
2934	+	r = Arrays.copyOf(r, n);
2935	+	}
2936	+	r[i++] = (T)it.next();
2937	+	}
2938	+	if (a == r && i < n) {
2939	+	r[i] = null; // null-terminate
2940	+	return r;
2941	+	}
2942	+	return (i == n) ? r : Arrays.copyOf(r, i);
2943	+	}
2944	+
2945	+	public final int hashCode() {
2946	+	int h = 0;
2947	+	for (Iterator<?> it = iter(); it.hasNext();)
2948	+	h += it.next().hashCode();
2949	+	return h;
2950	+	}
2951	+
2952	+	public final String toString() {
2953	+	StringBuilder sb = new StringBuilder();
2954	+	sb.append('[');
2955	+	Iterator<?> it = iter();
2956	+	if (it.hasNext()) {
2957	+	for (;;) {
2958	+	Object e = it.next();
2959	+	sb.append(e == this ? "(this Collection)" : e);
2960	+	if (!it.hasNext())
2961	+	break;
2962	+	sb.append(',').append(' ');
2963	+	}
2964	+	}
2965	+	return sb.append(']').toString();
2966	+	}
2967	+
2968	+	public final boolean containsAll(Collection<?> c) {
2969	+	if (c != this) {
2970	+	for (Iterator<?> it = c.iterator(); it.hasNext();) {
2971	+	Object e = it.next();
2972	+	if (e == null || !contains(e))
2973	+	return false;
2974	+	}
2975	+	}
2976	+	return true;
2977	+	}
2978	+
2979	+	public final boolean removeAll(Collection<?> c) {
2980	+	boolean modified = false;
2981	+	for (Iterator<?> it = iter(); it.hasNext();) {
2982	+	if (c.contains(it.next())) {
2983	+	it.remove();
2984	+	modified = true;
2985	+	}
2986	+	}
2987	+	return modified;
2988	+	}
2989	+
2990	+	public final boolean retainAll(Collection<?> c) {
2991	+	boolean modified = false;
2992	+	for (Iterator<?> it = iter(); it.hasNext();) {
2993	+	if (!c.contains(it.next())) {
2994	+	it.remove();
2995	+	modified = true;
2996	+	}
2997	+	}
2998	+	return modified;
2999	+	}
3000	+
3001	+	}
3002	+
3003	+	static final class KeySet<K,V> extends MapView<K,V> implements Set<K> {
3004	+	KeySet(ConcurrentHashMapV8<K, V> map)   { super(map); }
3005		public final boolean contains(Object o) { return map.containsKey(o); }
3006		public final boolean remove(Object o)   { return map.remove(o) != null; }
3007	+
3008		public final Iterator<K> iterator() {
3009		return new KeyIterator<K,V>(map);
3010		}
3011	+	final Iterator<?> iter() {
3012	+	return new KeyIterator<K,V>(map);
3013	+	}
3014	+	public final boolean add(K e) {
3015	+	throw new UnsupportedOperationException();
3016	+	}
3017	+	public final boolean addAll(Collection<? extends K> c) {
3018	+	throw new UnsupportedOperationException();
3019	+	}
3020	+	public boolean equals(Object o) {
3021	+	Set<?> c;
3022	+	return ((o instanceof Set) &&
3023	+	((c = (Set<?>)o) == this ||
3024	+	(containsAll(c) && c.containsAll(this))));
3025	+	}
3026		}
3027
3028	<	static final class Values<K,V> extends AbstractCollection<V> {
3029	<	final ConcurrentHashMapV8<K, V> map;
3030	<	Values(ConcurrentHashMapV8<K, V> map)   { this.map = map; }
1537	<
1538	<	public final int size()                 { return map.size(); }
1539	<	public final boolean isEmpty()          { return map.isEmpty(); }
1540	<	public final void clear()               { map.clear(); }
3028	>	static final class Values<K,V> extends MapView<K,V>
3029	>	implements Collection<V> {
3030	>	Values(ConcurrentHashMapV8<K, V> map)   { super(map); }
3031		public final boolean contains(Object o) { return map.containsValue(o); }
3032	+
3033	+	public final boolean remove(Object o) {
3034	+	if (o != null) {
3035	+	Iterator<V> it = new ValueIterator<K,V>(map);
3036	+	while (it.hasNext()) {
3037	+	if (o.equals(it.next())) {
3038	+	it.remove();
3039	+	return true;
3040	+	}
3041	+	}
3042	+	}
3043	+	return false;
3044	+	}
3045		public final Iterator<V> iterator() {
3046		return new ValueIterator<K,V>(map);
3047		}
3048	+	final Iterator<?> iter() {
3049	+	return new ValueIterator<K,V>(map);
3050	+	}
3051	+	public final boolean add(V e) {
3052	+	throw new UnsupportedOperationException();
3053	+	}
3054	+	public final boolean addAll(Collection<? extends V> c) {
3055	+	throw new UnsupportedOperationException();
3056	+	}
3057		}
3058
3059	<	static final class EntrySet<K,V> extends AbstractSet<Map.Entry<K,V>> {
3060	<	final ConcurrentHashMapV8<K, V> map;
3061	<	EntrySet(ConcurrentHashMapV8<K, V> map) { this.map = map; }
1550	<
1551	<	public final int size()                 { return map.size(); }
1552	<	public final boolean isEmpty()          { return map.isEmpty(); }
1553	<	public final void clear()               { map.clear(); }
1554	<	public final Iterator<Map.Entry<K,V>> iterator() {
1555	<	return new EntryIterator<K,V>(map);
1556	<	}
3059	>	static final class EntrySet<K,V> extends MapView<K,V>
3060	>	implements Set<Map.Entry<K,V>> {
3061	>	EntrySet(ConcurrentHashMapV8<K, V> map) { super(map); }
3062
3063		public final boolean contains(Object o) {
3064		Object k, v, r; Map.Entry<?,?> e;
#	Line 1571 | Line 3076 | public class ConcurrentHashMapV8<K, V>
3076		(v = e.getValue()) != null &&
3077		map.remove(k, v));
3078		}
3079	+
3080	+	public final Iterator<Map.Entry<K,V>> iterator() {
3081	+	return new EntryIterator<K,V>(map);
3082	+	}
3083	+	final Iterator<?> iter() {
3084	+	return new SnapshotEntryIterator<K,V>(map);
3085	+	}
3086	+	public final boolean add(Entry<K,V> e) {
3087	+	throw new UnsupportedOperationException();
3088	+	}
3089	+	public final boolean addAll(Collection<? extends Entry<K,V>> c) {
3090	+	throw new UnsupportedOperationException();
3091	+	}
3092	+	public boolean equals(Object o) {
3093	+	Set<?> c;
3094	+	return ((o instanceof Set) &&
3095	+	((c = (Set<?>)o) == this ||
3096	+	(containsAll(c) && c.containsAll(this))));
3097	+	}
3098		}
3099
3100		/* ---------------- Serialization Support -------------- */
#	Line 1626 | Line 3150 | public class ConcurrentHashMapV8<K, V>
3150		this.segments = null; // unneeded
3151		// initialize transient final field
3152		UNSAFE.putObjectVolatile(this, counterOffset, new LongAdder());
1629	–	this.targetCapacity = DEFAULT_CAPACITY;
3153
3154		// Create all nodes, then place in table once size is known
3155		long size = 0L;
#	Line 1635 | Line 3158 | public class ConcurrentHashMapV8<K, V>
3158		K k = (K) s.readObject();
3159		V v = (V) s.readObject();
3160		if (k != null && v != null) {
3161	<	p = new Node(spread(k.hashCode()), k, v, p);
3161	>	int h = spread(k.hashCode());
3162	>	p = new Node(h, k, v, p);
3163		++size;
3164		}
3165		else
#	Line 1643 | Line 3167 | public class ConcurrentHashMapV8<K, V>
3167		}
3168		if (p != null) {
3169		boolean init = false;
3170	<	if (resizing == 0 &&
3171	<	UNSAFE.compareAndSwapInt(this, resizingOffset, 0, 1)) {
3170	>	int n;
3171	>	if (size >= (long)(MAXIMUM_CAPACITY >>> 1))
3172	>	n = MAXIMUM_CAPACITY;
3173	>	else {
3174	>	int sz = (int)size;
3175	>	n = tableSizeFor(sz + (sz >>> 1) + 1);
3176	>	}
3177	>	int sc = sizeCtl;
3178	>	boolean collide = false;
3179	>	if (n > sc &&
3180	>	UNSAFE.compareAndSwapInt(this, sizeCtlOffset, sc, -1)) {
3181		try {
3182		if (table == null) {
3183		init = true;
1651	–	int n;
1652	–	if (size >= (long)(MAXIMUM_CAPACITY >>> 1))
1653	–	n = MAXIMUM_CAPACITY;
1654	–	else {
1655	–	int sz = (int)size;
1656	–	n = tableSizeFor(sz + (sz >>> 1) + 1);
1657	–	}
1658	–	threshold = n - (n >>> 2) - THRESHOLD_OFFSET;
3184		Node[] tab = new Node[n];
3185		int mask = n - 1;
3186		while (p != null) {
3187		int j = p.hash & mask;
3188		Node next = p.next;
3189	<	p.next = tabAt(tab, j);
3189	>	Node q = p.next = tabAt(tab, j);
3190		setTabAt(tab, j, p);
3191	+	if (!collide && q != null && q.hash == p.hash)
3192	+	collide = true;
3193		p = next;
3194		}
3195		table = tab;
3196		counter.add(size);
3197	+	sc = n - (n >>> 2);
3198		}
3199		} finally {
3200	<	resizing = 0;
3200	>	sizeCtl = sc;
3201	>	}
3202	>	if (collide) { // rescan and convert to TreeBins
3203	>	Node[] tab = table;
3204	>	for (int i = 0; i < tab.length; ++i) {
3205	>	int c = 0;
3206	>	for (Node e = tabAt(tab, i); e != null; e = e.next) {
3207	>	if (++c > TREE_THRESHOLD &&
3208	>	(e.key instanceof Comparable)) {
3209	>	replaceWithTreeBin(tab, i, e.key);
3210	>	break;
3211	>	}
3212	>	}
3213	>	}
3214		}
3215		}
3216		if (!init) { // Can only happen if unsafely published.
3217		while (p != null) {
3218	<	internalPut(p.key, p.val, true);
3218	>	internalPut(p.key, p.val);
3219		p = p.next;
3220		}
3221		}
3222	+
3223		}
3224		}
3225
3226		// Unsafe mechanics
3227		private static final sun.misc.Unsafe UNSAFE;
3228		private static final long counterOffset;
3229	<	private static final long resizingOffset;
3229	>	private static final long sizeCtlOffset;
3230		private static final long ABASE;
3231		private static final int ASHIFT;
3232
#	Line 1695 | Line 3237 | public class ConcurrentHashMapV8<K, V>
3237		Class<?> k = ConcurrentHashMapV8.class;
3238		counterOffset = UNSAFE.objectFieldOffset
3239		(k.getDeclaredField("counter"));
3240	<	resizingOffset = UNSAFE.objectFieldOffset
3241	<	(k.getDeclaredField("resizing"));
3240	>	sizeCtlOffset = UNSAFE.objectFieldOffset
3241	>	(k.getDeclaredField("sizeCtl"));
3242		Class<?> sc = Node[].class;
3243		ABASE = UNSAFE.arrayBaseOffset(sc);
3244		ss = UNSAFE.arrayIndexScale(sc);

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