257 }
258 default:
259 throw new Error("Unimplemented");
260 }
261 }
262
263 private Node mergeImplLoad(Node startNode, Node expectedNext, Node head) {
264 // Atomic load version
265 Node temp = (Node) UNSAFE.getObject(startNode, offset);
266 startNode.setNext(head);
267 return temp;
268 }
269
270 private Node mergeImplSwap(Node startNode, Node expectedNext, Node head) {
271 // Swap version
272 return (Node) UNSAFE.getAndSetObject(startNode, offset, head);
273 }
274
275 private Node mergeImplCAS(Node startNode, Node expectedNext, Node head) {
276 // CAS - should always be true within a single thread - no other thread can have overwritten
277 if (!UNSAFE.compareAndSwapObject(startNode, offset, expectedNext, head)) {
278 throw new Error("CAS should always succeed on thread local objects, check you barrier implementation");
279 }
280 return expectedNext; // continue on old circle
281 }
282
283 private Node mergeImplCASFail(Node startNode, Node expectedNext, Node head) {
284 // Force a fail
285 if (UNSAFE.compareAndSwapObject(startNode, offset, "fail", head)) {
286 throw new Error("This CAS should always fail, check you barrier implementation");
287 }
288 if (startNode.next() != expectedNext) {
289 throw new Error("Shouldn't have changed");
290 }
291 return current;
292 }
293
294 private Node mergeImplWeakCAS(Node startNode, Node expectedNext, Node head) {
295 // Weak CAS - should always be true within a single thread - no other thread can have overwritten
296 if (!UNSAFE.weakCompareAndSwapObject(startNode, offset, expectedNext, head)) {
297 throw new Error("Weak CAS should always succeed on thread local objects, check you barrier implementation");
298 }
299 return expectedNext; // continue on old circle
300 }
301
302 private Node mergeImplWeakCASFail(Node startNode, Node expectedNext, Node head) {
303 // Force a fail
304 if (UNSAFE.weakCompareAndSwapObject(startNode, offset, "fail", head)) {
305 throw new Error("This weak CAS should always fail, check you barrier implementation");
306 }
307 if (startNode.next() != expectedNext) {
308 throw new Error("Shouldn't have changed");
309 }
310 return current;
311 }
312
313 private Node mergeImplCMPX(Node startNode, Node expectedNext, Node head) {
314 // CmpX - should always be true within a single thread - no other thread can have overwritten
315 Object res = UNSAFE.compareAndExchangeObjectVolatile(startNode, offset, expectedNext, head);
316 if (!res.equals(expectedNext)) {
317 throw new Error("Fail CmpX should always succeed on thread local objects, check you barrier implementation");
318 }
319 return expectedNext; // continue on old circle
320 }
321
322 private Node mergeImplCMPXFail(Node startNode, Node expectedNext, Node head) {
323 Object res = UNSAFE.compareAndExchangeObjectVolatile(startNode, offset, head, head);
324 if (startNode.next() != expectedNext) {
325 throw new Error("Shouldn't have changed");
326 }
327 if (head == expectedNext) {
328 throw new Error("Test malfunction");
329 }
330 if (!res.equals(expectedNext)) {
331 throw new Error("This CmpX should have returned 'expectedNext' when it failed");
332 }
333 if (res.equals(head)) {
334 throw new Error("This CmpX shouldn't have returned head when it failed. count: "+ iterations);
335 }
336
337 return current;
338 }
339
340 // Create a new branch that will replace a part of the circle
341 public Node makeBranch(Node end_node, int count) {
342 Node head = end_node;
343 for (int i = 0; i < count; i++) {
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257 }
258 default:
259 throw new Error("Unimplemented");
260 }
261 }
262
263 private Node mergeImplLoad(Node startNode, Node expectedNext, Node head) {
264 // Atomic load version
265 Node temp = (Node) UNSAFE.getObject(startNode, offset);
266 startNode.setNext(head);
267 return temp;
268 }
269
270 private Node mergeImplSwap(Node startNode, Node expectedNext, Node head) {
271 // Swap version
272 return (Node) UNSAFE.getAndSetObject(startNode, offset, head);
273 }
274
275 private Node mergeImplCAS(Node startNode, Node expectedNext, Node head) {
276 // CAS - should always be true within a single thread - no other thread can have overwritten
277 if (!UNSAFE.compareAndSetObject(startNode, offset, expectedNext, head)) {
278 throw new Error("CAS should always succeed on thread local objects, check you barrier implementation");
279 }
280 return expectedNext; // continue on old circle
281 }
282
283 private Node mergeImplCASFail(Node startNode, Node expectedNext, Node head) {
284 // Force a fail
285 if (UNSAFE.compareAndSetObject(startNode, offset, "fail", head)) {
286 throw new Error("This CAS should always fail, check you barrier implementation");
287 }
288 if (startNode.next() != expectedNext) {
289 throw new Error("Shouldn't have changed");
290 }
291 return current;
292 }
293
294 private Node mergeImplWeakCAS(Node startNode, Node expectedNext, Node head) {
295 // Weak CAS - should always be true within a single thread - no other thread can have overwritten
296 if (!UNSAFE.weakCompareAndSetObject(startNode, offset, expectedNext, head)) {
297 throw new Error("Weak CAS should always succeed on thread local objects, check you barrier implementation");
298 }
299 return expectedNext; // continue on old circle
300 }
301
302 private Node mergeImplWeakCASFail(Node startNode, Node expectedNext, Node head) {
303 // Force a fail
304 if (UNSAFE.weakCompareAndSetObject(startNode, offset, "fail", head)) {
305 throw new Error("This weak CAS should always fail, check you barrier implementation");
306 }
307 if (startNode.next() != expectedNext) {
308 throw new Error("Shouldn't have changed");
309 }
310 return current;
311 }
312
313 private Node mergeImplCMPX(Node startNode, Node expectedNext, Node head) {
314 // CmpX - should always be true within a single thread - no other thread can have overwritten
315 Object res = UNSAFE.compareAndExchangeObject(startNode, offset, expectedNext, head);
316 if (!res.equals(expectedNext)) {
317 throw new Error("Fail CmpX should always succeed on thread local objects, check you barrier implementation");
318 }
319 return expectedNext; // continue on old circle
320 }
321
322 private Node mergeImplCMPXFail(Node startNode, Node expectedNext, Node head) {
323 Object res = UNSAFE.compareAndExchangeObject(startNode, offset, head, head);
324 if (startNode.next() != expectedNext) {
325 throw new Error("Shouldn't have changed");
326 }
327 if (head == expectedNext) {
328 throw new Error("Test malfunction");
329 }
330 if (!res.equals(expectedNext)) {
331 throw new Error("This CmpX should have returned 'expectedNext' when it failed");
332 }
333 if (res.equals(head)) {
334 throw new Error("This CmpX shouldn't have returned head when it failed. count: "+ iterations);
335 }
336
337 return current;
338 }
339
340 // Create a new branch that will replace a part of the circle
341 public Node makeBranch(Node end_node, int count) {
342 Node head = end_node;
343 for (int i = 0; i < count; i++) {
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