Update in HP decoders:
[u/mrichter/AliRoot.git] / MUON / AliMUONTriggerDDLDecoder.h
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1788245f 1#ifndef ALIMUONTRIGGERDDLDECODER_H
2#define ALIMUONTRIGGERDDLDECODER_H
3/**************************************************************************
4 * This file is property of and copyright by the ALICE HLT Project *
5 * All rights reserved. *
6 * *
7 * Primary Authors: *
8 * Artur Szostak <artursz@iafrica.com> *
9 * *
10 * Permission to use, copy, modify and distribute this software and its *
11 * documentation strictly for non-commercial purposes is hereby granted *
12 * without fee, provided that the above copyright notice appears in all *
13 * copies and that both the copyright notice and this permission notice *
14 * appear in the supporting documentation. The authors make no claims *
15 * about the suitability of this software for any purpose. It is *
16 * provided "as is" without express or implied warranty. *
17 **************************************************************************/
18
19/* $Id$ */
20
21///
22/// \file AliMUONTriggerDDLDecoder.h
23/// \author Artur Szostak <artursz@iafrica.com>
24/// \date 28-11-2007
25/// \brief Implementation of a high performance DDL decoder for the muon trigger.
26///
27/// This file implementes the AliMUONTriggerDDLDecoder class, which contains
28/// the core logic for decoding the payload in DDL streams comming from the muon
29/// spectrometer's hardware trigger in a very efficient manner.
30///
31/// This implementation is derived from work done by Christian Finck for the
32/// AliMUONPayloadTrigger class.
33///
34/// Note to maintainers: Please remember that this file is used by the online
35/// dHLT system. As an online system, the dHLT requires the fastest code possible
36/// in the decoders to satisfy its timing constraints. The performance impact
37/// must be checked before any proposed modification is made to this file.
38///
39
40#include "AliMUONTriggerDDLDecoderEventHandler.h"
41
42/// \ingroup raw
43/// \class AliMUONTriggerDDLDecoder
44/// \brief A high performance decoder class for MUON trigger DDL data.
45///
46/// This class implements a high performance decoder for decoding DDL payload
47/// data coming from the muon spectrometers trigger stations.
48/// It has been implemented using the event driven paradigm with templates,
49/// which allows us to minimise the number of method calls made in the inner
50/// loops of the algorithm and minimise the memory footprint.
51/// At least for optimised production compilations.
52/// The decoder class only contains the basic decoding and error checking logic.
53/// It calls methods such as OnNewBuffer, OnDarcHeader, OnNewRegionalStruct,
54/// OnLocalStruct etc in the event handler during the decoding to return the
55/// decoded data and headers.
56/// The event handler class is nothing more than a callback interface to deliver
57/// the next chunks of decoded data.
58/// To actually do something with the data, one needs to implement a custom
59/// event handler (callback) class by inheriting from AliMUONTriggerDDLDecoderEventHandler
60/// and overriding the callback methods like so:
61/// \code
62/// class MyCustomHandler : public AliMUONTriggerDDLDecoderEventHandler
63/// {
64/// public:
65/// void OnLocalStruct(const AliMUONLocalInfoStruct* localStruct,
66/// const AliMUONLocalScalarsStruct* scalars)
67/// {
68/// // I can do something with the data in 'localStruct' here.
69/// // and the 'scalars' if they are not NULL.
70/// }
71/// };
72/// \endcode
73///
74/// Once the custom handler is written then the decoder is instantiated as
75/// shown below, to use your new custom handler. Also to start decoding one needs
76/// to call the Decode() method of the decoder.
77/// \code
78/// AliMUONTriggerDDLDecoder<MyCustomHandler> myDecoder;
79/// muDecoder.Decoder(buffer, bufferSize);
80/// \endcode
81///
82/// Note that this class was written as a template on purpose. To maximise the
83/// compilers chance to make optimisations and inline the code we must use a template.
84/// Depending on exactly what you do inside your handler, the decoder could be
85/// significantly slower if run time polymorphism was used, i.e. making the class
86/// AliMUONTriggerDDLDecoderEventHandler abstract and using virtual methods.
87///
88template <class EventHandler>
89class AliMUONTriggerDDLDecoder
90{
91public:
92
93 /// Default contructor.
94 AliMUONTriggerDDLDecoder() :
95 fExitOnError(true), fTryRecover(false),
96 fAutoDetectScalars(false), fHadError(false),
97 fNoRegionals(0), fMaxRegionals(8), fMaxLocals(16),
98 fHandler()
99 {}
100
101 /// Constant method to return the event handler instance.
102 const EventHandler& GetHandler() const { return fHandler; }
103
104 /// Returns the event handler instance.
105 EventHandler& GetHandler() { return fHandler; }
106
107 /// Returns the "exit on error" flag.
108 /// i.e. should the decoder stop on the very first error found.
109 bool ExitOnError() const { return fExitOnError; }
110
111 /// Sets the "exit on error" flag.
112 /// i.e. should the decoder stop on the very first error found.
113 void ExitOnError(bool value) { fExitOnError = value; }
114
115 /// Returns the "try to recover from errors" flag.
116 /// i.e. should the decoder try to recover from errors found in the
117 /// payload headers.
118 bool TryRecover() const { return fTryRecover; }
119
120 /// Sets the "try to recover from errors" flag.
121 /// i.e. should the decoder try to recover from errors found in the
122 /// payload headers.
123 void TryRecover(bool value) { fTryRecover = value; }
124
125 /// Returns the flag indicating if we should check for the scalars of
126 /// software triggers automatically or not.
127 bool AutoDetectScalars() const { return fAutoDetectScalars; }
128
129 /// Sets the flag indicating if we should check for the scalars of
130 /// software triggers automatically or not. If set to true then the
131 /// scalarEvent parameter of the Decode method is ignored.
132 void AutoDetectScalars(bool value) { fAutoDetectScalars = value; }
133
134 /// Returns the maximum regional structure count expected in the DDL payload.
135 UInt_t MaxRegionals() const { return fMaxRegionals; }
136
137 /// Sets the maximum regional structure count expected in the DDL payload.
138 void MaxRegionals(UInt_t n) { fMaxRegionals = n; }
139
140 /// Returns the number of regional structures we actually attempted to decode.
141 UInt_t RegionalsDecoded() const { return fNoRegionals; }
142
143 /// Returns the maximum local structure count expected in any given regional
144 /// card structure within the DDL payload.
145 UInt_t MaxLocals() const { return fMaxLocals; }
146
147 /// Sets the maximum local structure count expected in any given regional
148 /// card structure within the DDL payload.
149 void MaxLocals(UInt_t n) { fMaxLocals = n; }
150
151 /// This method decodes the DDL payload contained in the buffer.
152 bool Decode(const void* buffer, UInt_t bufferSize, bool scalarEvent = false);
153
154 /// Returns the end of DARC marker key.
155 static UInt_t EndOfDarcWord() { return fgkEndOfDarc; }
156
157 /// Returns the end of global header marker key.
158 static UInt_t EndOfGlobalWord() { return fgkEndOfGlobal; }
159
160 /// Returns the end of regional structure marker key.
161 static UInt_t EndOfRegionalWord() { return fgkEndOfReg; }
162
163 /// Returns the regional error word.
164 static UInt_t RegionalErrorWord() { return fgkErrorWord; }
165
166 /// Returns the end of local structure marker key.
167 static UInt_t EndOfLocalWord() { return fgkEndOfLocal; }
168
169 /// Returns the local card disable word.
170 static UInt_t LocalDisableWord() { return fgkDisableWord; }
171
172 /// Returns value of default DARC type.
173 static UInt_t DarcDefaultType() { return fgkDarcDefaultType; }
174
175 /// Returns value of Vadorh DARC type.
176 static UInt_t DarcVadorhType() { return fgkDarcVadorhType; }
177
178private:
179
180 bool fExitOnError; ///< Indicates if we should exit on the very first error.
181 bool fTryRecover; ///< Indicates if we should try recover from a corrupt structures.
182 bool fAutoDetectScalars; ///< Flag to indicate if we should auto-detect if there are scalars in the data.
183 bool fHadError; ///< Indicates if we had an error decoding the data.
184 UInt_t fNoRegionals; ///< The number of regional card structures actually decoded.
185 UInt_t fMaxRegionals; ///< Maximum number of regional card structures allowed in a DDL stream.
186 UInt_t fMaxLocals; ///< Maximum number of local card structures per regional structure allowed in a DDL stream.
187 EventHandler fHandler; ///< The event handler which deals with the generated parsing events.
188
189 void DecodeBuffer(const UChar_t* start, const UChar_t* end, bool scalarEvent);
190 void DecodeRegionalStructs(const UChar_t* start, const UChar_t* end, bool scalarEvent);
191 const UChar_t* DecodeLocalStructs(const UChar_t* start, const UChar_t* end, bool scalarEvent);
192
193 const UChar_t* FindKey(
194 UInt_t key, const UChar_t* start, const UChar_t* end
195 );
196
197 static const UInt_t fgkEndOfDarc; ///< Indicates the end of the DARC header.
198 static const UInt_t fgkEndOfGlobal; ///< Indicates the end of the global header just after the DARC header.
199 static const UInt_t fgkEndOfReg; ///< Indicates the end of a regional card structure.
200 static const UInt_t fgkErrorWord; ///< The error word when a regional board is missing.
201 static const UInt_t fgkEndOfLocal; ///< Indicates the end of a local card structure.
202 static const UInt_t fgkDisableWord; ///< Word used to fill "empty" slots.
203 static const UInt_t fgkDarcDefaultType; ///< default type for DARC def.
204 static const UInt_t fgkDarcVadorhType; ///< default type for DARC vadorh
205};
206
207//_____________________________________________________________________________
208
209// The following are the structure key words which are used to demarcate (identify
210// the end) of the structures within the raw trigger data.
211template <class EventHandler>
212const UInt_t AliMUONTriggerDDLDecoder<EventHandler>::fgkEndOfDarc = 0xDEADFACE;
213template <class EventHandler>
214const UInt_t AliMUONTriggerDDLDecoder<EventHandler>::fgkEndOfGlobal = 0xDEADBEEF;
215template <class EventHandler>
216const UInt_t AliMUONTriggerDDLDecoder<EventHandler>::fgkEndOfReg = 0xBEEFFACE;
217template <class EventHandler>
218const UInt_t AliMUONTriggerDDLDecoder<EventHandler>::fgkErrorWord = 0xCAFEDEAD;
219template <class EventHandler>
220const UInt_t AliMUONTriggerDDLDecoder<EventHandler>::fgkEndOfLocal = 0xCAFEFADE;
221template <class EventHandler>
222const UInt_t AliMUONTriggerDDLDecoder<EventHandler>::fgkDisableWord = 0x010CDEAD;
223template <class EventHandler>
224const UInt_t AliMUONTriggerDDLDecoder<EventHandler>::fgkDarcDefaultType = 0x6;
225template <class EventHandler>
226const UInt_t AliMUONTriggerDDLDecoder<EventHandler>::fgkDarcVadorhType = 0x4;
227
228
229template <class EventHandler>
230bool AliMUONTriggerDDLDecoder<EventHandler>::Decode(
231 const void* buffer, UInt_t bufferSize, bool scalarEvent
232 )
233{
234 /// This method should be called to actually decode the DDL payload
235 /// contained in a memory buffer. The payload should be in the muon trigger
236 /// system DDL stream format otherwise it will be recognised as corrupt.
237 /// As the decoder progresses it will make method calls to the event handler
238 /// instance (which can be accessed with the GetHandler() method) to indicate
239 /// the start of the DARC header, global header, new regional structures and
240 /// local card structures.
241 ///
242 /// If an error occurs during the parse, because the data is corrupt, then
243 /// the OnError method is called indicating what the problem was.
244 /// Decoding will stop at this point unless the fExitOnError flag is set
245 /// to false. There is an optional flag fTryRecover which can enable logic
246 /// which will attempt to recover from corruption of the data structures
247 /// in the DDL payload, if they are found to be inconsistent (assumed corrupt).
248 /// The recovery procedure simply involves trying to find in the DDL stream
249 /// the location of the expected end of header/structure marker/key or the
250 /// next expected key, and then continue decoding from there. This kind of
251 /// recovery logic is (and should be) turned off by default and only
252 /// enabled when trying to recover corrupted data.
253 ///
254 /// \param buffer This is the pointer to the start of the memory buffer
255 /// containing the DDL payload. Remember that this must be the start of
256 /// the payload and not the DDL stream. That is, this pointer should be
257 /// equal to: DDL start pointer + 8 * sizeof(UInt_t).
258 /// \param bufferSize This is the pointer to the first byte just past the
259 /// end of the block structure.
260 /// \param scalarEvent Set to true if this DDL contains a scalar event
261 /// and false if it is a normal physics event. If the fAutoDetectScalars
262 /// flag is true then we ignore this parameter.
263 /// \return Returns false if there was any problem with decoding the data,
264 /// and true otherwise. Note: the data may have been partially decoded
265 /// even if false was returned, which would be indicated by at least one
266 /// call to the event handler's OnLocalStruct or OnNewRegionalStruct methods.
267
268 assert( buffer != NULL );
269
270 fHadError = false;
271
272 // We are basically implementing something like a recursive decent parser.
273 // So start by marking the start of buffer position and end of buffer.
274 const UChar_t* start = reinterpret_cast<const UChar_t*>(buffer);
275 const UChar_t* end = start + bufferSize;
276
277 fHandler.OnNewBuffer(buffer, bufferSize);
278 DecodeBuffer(start, end, scalarEvent);
279 fHandler.OnEndOfBuffer(buffer, bufferSize);
280 return not fHadError;
281}
282
283
284template <class EventHandler>
285void AliMUONTriggerDDLDecoder<EventHandler>::DecodeBuffer(
286 const UChar_t* start, const UChar_t* end, bool scalarEvent
287 )
288{
289 /// This method does the work to decode the buffer's payload data. It
290 /// unpacks the DARC header, the global header, then calls the
291 /// DecodeRegionalStructs() method to decode the regional structures.
292 /// For the DARC and global headers the methods OnDarcHeader and
293 /// OnGlobalHeader of the event handler object are called respectively.
294 /// \param start This is the pointer to the start of the buffer to decode.
295 /// \param end This is the pointer to the first byte just past the
296 /// end of the buffer.
297 /// \param scalarEvent Set to true if this DDL contains a scalar event
298 /// and false if it is a normal physics event.
299 ///
300 /// fHadError is set to true if there were any errors decoding the buffer
301 /// and the OnError method of the callback event handler is called for
302 /// each error.
303
304 const UChar_t* current = start;
305
306 // Mark the DARC header, but check that we do not overrun the buffer.
307 const UInt_t* darcHeader = reinterpret_cast<const UInt_t*>(current);
308 current += sizeof(UInt_t);
309 if (current > end)
310 {
311 // Indicate we had an error and stop the decoding because we
312 // hit the end of the buffer already.
313 fHandler.OnError(EventHandler::kNoDarcHeader, darcHeader);
314 fHadError = true;
315 return;
316 }
317
318 // Check if we need to figure out if this is a scalar event.
319 // If we do, then we do this by checking the event type in the DARC header
320 // and double checking this by checking if the fgkEndOfDarc key is in the
321 // expected location for a scalar event DDL payload.
322 if (fAutoDetectScalars)
323 {
324 const UInt_t* expectedEndOfDarc = reinterpret_cast<const UInt_t*>(
325 current + sizeof(AliMUONDarcScalarsStruct)
326 );
327
328 // First make sure not to read past the end of buffer. Then check
329 // the value of the event type in the DARC header.
330 // Physics events are indicated by the two trigger bits of the
331 // DARC header set to 01b. Everything else is a software trigger
332 // of some sort.
333 if (reinterpret_cast<const UChar_t*>(expectedEndOfDarc+1) <= end and
334 EventHandler::GetDarcEventType(*darcHeader) != 0x1
335 and *expectedEndOfDarc == fgkEndOfDarc
336 )
337 {
338 scalarEvent = true;
339 }
340 else
341 {
342 scalarEvent = false;
343 }
344 }
345
346 // Detect how many regional blocks we expect. If we have no idea then
347 // just use what the maximum setting is.
348 switch (EventHandler::GetDarcType(*darcHeader))
349 {
350 case fgkDarcVadorhType: fNoRegionals = 1; break;
351 case fgkDarcDefaultType: fNoRegionals = 8; break;
352 default: fNoRegionals = fMaxRegionals; break;
353 }
354
355 // Check if the DARC header indicates we expect more regionals than we
356 // are allowed to decode according to our max regional structures count.
357 // If we do then this is an error and we should indicate it and exit
358 // if so requested by the user. Also we can fix the number of regionals
359 // to expect if we are trying to recover from errors.
360 if (fNoRegionals > fMaxRegionals)
361 {
362 fHandler.OnError(EventHandler::kTooManyRegionals, darcHeader);
363 fHadError = true;
364 if (fExitOnError) return;
365 if (fTryRecover)
366 {
367 fNoRegionals = fMaxRegionals;
368 }
369 }
370
371 // Check that the DARC header indicates correctly if we are a scalar event or not.
372 bool darcShowsScalar = (EventHandler::GetDarcEventType(*darcHeader) != 0x1);
373 if (darcShowsScalar != scalarEvent)
374 {
375 // Indicate we had an error and stop the decoding if so requested
376 // by the user.
377 fHandler.OnError(EventHandler::kWrongEventType, darcHeader);
378 fHadError = true;
379 if (fExitOnError) return;
380 }
381
382 // Decode the DARC scalars if this is a scalar event.
383 const AliMUONDarcScalarsStruct* darcScalars = NULL;
384 if (scalarEvent)
385 {
386 darcScalars = reinterpret_cast<const AliMUONDarcScalarsStruct*>(current);
387 current += sizeof(AliMUONDarcScalarsStruct);
388 if (current > end)
389 {
390 // Indicate we had an error and stop the decoding because we
391 // hit the end of the buffer already.
392 fHandler.OnError(EventHandler::kNoDarcScalars, darcScalars);
393 fHadError = true;
394 return;
395 }
396 }
397
398 // Now check that the end of DARC header marker is OK.
399 const UInt_t* endOfDarc = reinterpret_cast<const UInt_t*>(current);
400 current += sizeof(UInt_t);
401 if (current > end)
402 {
403 // Indicate we had an error and stop the decoding because we
404 // hit the end of the buffer already.
405 fHandler.OnError(EventHandler::kNoEndOfDarc, endOfDarc);
406 fHadError = true;
407 return;
408 }
409 if (*endOfDarc != fgkEndOfDarc)
410 {
411 // Indicate we had an error and stop the decoding if so requested
412 // by the user.
413 fHandler.OnError(EventHandler::kBadEndOfDarc, endOfDarc);
414 fHadError = true;
415 if (fExitOnError) return;
416
417 // If the user requested for us to try and recover from structure
418 // errors then we need to try locate the key in the data stream
419 // and continue decoding from there.
420 if (fTryRecover)
421 {
422 const UChar_t* keypos = FindKey(fgkEndOfDarc,
423 reinterpret_cast<const UChar_t*>(darcHeader),
424 end
425 );
426 if (keypos != NULL)
427 {
428 // remember to continue decoding just past the key.
429 current = keypos + sizeof(UInt_t);
430 }
431 }
432 }
433
434 fHandler.OnDarcHeader(*darcHeader, darcScalars, current);
435
436 // Next, we mark the Global header and check that we do not overrun the buffer.
437 const AliMUONGlobalHeaderStruct* globalHeader =
438 reinterpret_cast<const AliMUONGlobalHeaderStruct*>(current);
439 current += sizeof(AliMUONGlobalHeaderStruct);
440 if (current > end)
441 {
442 // Indicate we had an error and stop the decoding because we
443 // hit the end of the buffer already.
444 fHandler.OnError(EventHandler::kNoGlobalHeader, globalHeader);
445 fHadError = true;
446 return;
447 }
448
449 // Decode the global scalars if this is a scalar event.
450 const AliMUONGlobalScalarsStruct* globalScalars = NULL;
451 if (scalarEvent)
452 {
453 globalScalars = reinterpret_cast<const AliMUONGlobalScalarsStruct*>(current);
454 current += sizeof(AliMUONGlobalScalarsStruct);
455 if (current > end)
456 {
457 // Indicate we had an error and stop the decoding because we
458 // hit the end of the buffer already.
459 fHandler.OnError(EventHandler::kNoGlobalScalars, globalScalars);
460 fHadError = true;
461 return;
462 }
463 }
464
465 // Now check that the end of global header marker is OK.
466 const UInt_t* endOfGlobal = reinterpret_cast<const UInt_t*>(current);
467 current += sizeof(UInt_t);
468 if (current > end)
469 {
470 // Indicate we had an error and stop the decoding because we
471 // hit the end of the buffer already.
472 fHandler.OnError(EventHandler::kNoEndOfGlobal, endOfGlobal);
473 fHadError = true;
474 return;
475 }
476 if (*endOfGlobal != fgkEndOfGlobal)
477 {
478 // Indicate we had an error and stop the decoding if so requested
479 // by the user.
480 fHandler.OnError(EventHandler::kBadEndOfGlobal, endOfGlobal);
481 fHadError = true;
482 if (fExitOnError) return;
483
484 // If the user requested for us to try and recover from structure
485 // errors then we need to try locate the key in the data stream
486 // and continue decoding from there.
487 if (fTryRecover)
488 {
489 const UChar_t* keypos = FindKey(fgkEndOfGlobal,
490 reinterpret_cast<const UChar_t*>(globalHeader),
491 end
492 );
493 if (keypos != NULL)
494 {
495 // remember to continue decoding just past the key.
496 current = keypos + sizeof(UInt_t);
497 }
498 }
499 }
500
501 fHandler.OnGlobalHeader(globalHeader, globalScalars, current);
502
503 DecodeRegionalStructs(current, end, scalarEvent);
504}
505
506
507template <class EventHandler>
508void AliMUONTriggerDDLDecoder<EventHandler>::DecodeRegionalStructs(
509 const UChar_t* start, const UChar_t* end, bool scalarEvent
510 )
511{
512 /// This method decodes the regional structures in the DDL data.
513 /// For each regional header found, the OnNewRegionalStruct method of
514 /// the event handler is called, to signal the start of each
515 /// new regional structure. The DecodeLocalStructs() method is then
516 /// called to decode the local trigger structures. Finally, a symmetrical
517 /// call to OnEndOfRegionalStruct of the event handler is called to
518 /// signal that the regional structure has been decoded.
519 /// \param start This is the pointer to the start of the buffer.
520 /// \param end This is the pointer to the first byte just past the
521 /// end of the buffer.
522 /// \param scalarEvent Set to true if this DDL contains a scalar event
523 /// and false if it is a normal physics event.
524 ///
525 /// fHadError is set to true if there were any errors decoding the buffer
526 /// and the OnError method of the callback event handler is called for
527 /// each error.
528
529 const UChar_t* current = start;
530
531 for (UInt_t iReg = 0; iReg < fNoRegionals; iReg++)
532 {
533 const AliMUONRegionalHeaderStruct* regionalHeader =
534 reinterpret_cast<const AliMUONRegionalHeaderStruct*>(current);
535 current += sizeof(AliMUONRegionalHeaderStruct);
536
537 if (current > end)
538 {
539 // So we only got part of a regional header, nothing to do but
540 // report the error and exit.
541 fHandler.OnError(EventHandler::kNoRegionalHeader, regionalHeader);
542 fHadError = true;
543 return;
544 }
545
546 // Skip empty regional board (not connected or with error reading).
547 if (regionalHeader->fDarcWord == fgkErrorWord)
548 {
549 //current += sizeof(AliMUONRegionalHeaderStruct); // already done above
550 if (scalarEvent)
551 current += sizeof(AliMUONRegionalScalarsStruct);
552 current += sizeof(UInt_t); // skip the end of regional structure key.
553
554 // now also skip the local structure part:
555 current += fMaxLocals * sizeof(AliMUONLocalInfoStruct);
556 if (scalarEvent)
557 current += fMaxLocals * sizeof(AliMUONLocalScalarsStruct);
558 current += fMaxLocals * sizeof(UInt_t); // skip all the end of local structure keys.
559
560 continue;
561 }
562
563 // Decode the regional scalar words if this is a scalar event.
564 const AliMUONRegionalScalarsStruct* regionalScalars = NULL;
565 if (scalarEvent)
566 {
567 regionalScalars = reinterpret_cast<const AliMUONRegionalScalarsStruct*>(current);
568 current += sizeof(AliMUONRegionalScalarsStruct);
569 if (current > end)
570 {
571 // Indicate we had an error and stop the decoding because we
572 // hit the end of the buffer already.
573 fHandler.OnError(EventHandler::kNoRegionalScalars, regionalScalars);
574 fHadError = true;
575 return;
576 }
577 }
578
579 // Now check that the end of regional header marker is OK.
580 const UInt_t* endOfRegional = reinterpret_cast<const UInt_t*>(current);
581 current += sizeof(UInt_t);
582 if (current > end)
583 {
584 // Indicate we had an error and stop the decoding because we
585 // hit the end of the buffer already.
586 fHandler.OnError(EventHandler::kNoEndOfRegional, endOfRegional);
587 fHadError = true;
588 return;
589 }
590 if (*endOfRegional != fgkEndOfReg)
591 {
592 // Indicate we had an error and stop the decoding if so requested
593 // by the user.
594 fHandler.OnError(EventHandler::kBadEndOfRegional, endOfRegional);
595 fHadError = true;
596 if (fExitOnError) return;
597
598 // If the user requested for us to try and recover from structure
599 // errors then we need to try locate the key in the data stream
600 // and continue decoding from there.
601 if (fTryRecover)
602 {
603 const UChar_t* keypos = FindKey(fgkEndOfReg,
604 reinterpret_cast<const UChar_t*>(regionalHeader),
605 end
606 );
607
608 // If the fgkEndOfReg key was found exactly one regional
609 // structure later then we should not adjust the current
610 // decoding position because it is more likely that the
611 // end of regional structure key was just corrupt rather
612 // than offset.
613 // If we could not find another good key then just continue.
614 size_t sizeOfRegional = sizeof(AliMUONRegionalHeaderStruct) + sizeof(UInt_t)
615 + fMaxLocals * (sizeof(AliMUONLocalInfoStruct) + sizeof(UInt_t));
616 if (scalarEvent)
617 {
618 sizeOfRegional += sizeof(AliMUONRegionalScalarsStruct)
619 + fMaxLocals * sizeof(AliMUONLocalScalarsStruct);
620 }
621
622 if (keypos != NULL and keypos != current + sizeOfRegional)
623 {
624 current = keypos + sizeof(UInt_t);
625 }
626 }
627 }
628
629 // Tell the handler that we have a new regional block and decode it.
630 // When done, tell the handler again.
631 const UChar_t* startOfLocals = current;
632 fHandler.OnNewRegionalStruct(regionalHeader, regionalScalars, startOfLocals);
633 current = DecodeLocalStructs(current, end, scalarEvent);
634 fHandler.OnEndOfRegionalStruct(regionalHeader, regionalScalars, startOfLocals);
635 }
636
637 // Now just check that there is no extra rubbish at the end of the DDL.
638 if (current != end)
639 {
640 fHandler.OnError(EventHandler::kBufferTooBig, current);
641 fHadError = true;
642 }
643}
644
645
646template <class EventHandler>
647const UChar_t* AliMUONTriggerDDLDecoder<EventHandler>::DecodeLocalStructs(
648 const UChar_t* start, const UChar_t* end, bool scalarEvent
649 )
650{
651 /// This method decodes the local structures in the DDL data for a
652 /// single regional structure. For each local trigger structure found,
653 /// the OnLocalStruct method of the event handler is called.
654 /// \param start This is the pointer to the start of the regional structure
655 /// payload (The pointer just past the regional header key).
656 /// \param end This is the pointer to the first byte just past the
657 /// end of the buffer.
658 /// \param scalarEvent Set to true if this DDL contains a scalar event
659 /// and false if it is a normal physics event.
660 /// \returns The position in the buffer where this method stopped decoding.
661 ///
662 /// fHadError is set to true if there were any errors decoding the buffer
663 /// and the OnError method of the callback event handler is called for
664 /// each error.
665
666 const UChar_t* current = start;
667
668 for (UInt_t iLocal = 0; iLocal < fMaxLocals; iLocal++)
669 {
670 const AliMUONLocalInfoStruct* localStruct =
671 reinterpret_cast<const AliMUONLocalInfoStruct*>(current);
672 current += sizeof(AliMUONLocalInfoStruct);
673
674 if (current > end)
675 {
676 // So we only got part of a local structure, nothing to do but
677 // report the error and exit.
678 fHandler.OnError(EventHandler::kNoLocalStruct, localStruct);
679 fHadError = true;
680 return end;
681 }
682
683 // Skip empty local board if card not notified.
684 if (localStruct->fX2X1 == fgkDisableWord and
685 localStruct->fX4X3 == fgkDisableWord and
686 localStruct->fY2Y1 == fgkDisableWord and
687 localStruct->fY4Y3 == fgkDisableWord and
688 localStruct->fTriggerBits == fgkDisableWord
689 )
690 {
691 //current += sizeof(AliMUONLocalInfoStruct); // already done above
692 if (scalarEvent)
693 current += sizeof(AliMUONLocalScalarsStruct);
694 current += sizeof(UInt_t); // skip the end of local structure key.
695 continue;
696 }
697
698 // Decode the regional scalar words if this is a scalar event.
699 const AliMUONLocalScalarsStruct* localScalars = NULL;
700 if (scalarEvent)
701 {
702 localScalars = reinterpret_cast<const AliMUONLocalScalarsStruct*>(current);
703 current += sizeof(AliMUONLocalScalarsStruct);
704 if (current > end)
705 {
706 // Indicate we had an error and stop the decoding because we
707 // hit the end of the buffer already.
708 fHandler.OnError(EventHandler::kNoLocalScalars, localScalars);
709 fHadError = true;
710 return end;
711 }
712 }
713
714 // Now check that the end of regional header marker is OK.
715 const UInt_t* endOfLocal = reinterpret_cast<const UInt_t*>(current);
716 current += sizeof(UInt_t);
717 if (current > end)
718 {
719 // Indicate we had an error and stop the decoding because we
720 // hit the end of the buffer already. We can however signal that
721 // we got a local structure, because the buffer contains enough
722 // data to potencially contain the real data of the structure.
723 fHandler.OnError(EventHandler::kNoEndOfLocal, endOfLocal);
724 if (not fExitOnError)
725 {
726 fHandler.OnLocalStruct(localStruct, localScalars);
727 }
728 fHadError = true;
729 return end;
730 }
731 if (*endOfLocal != fgkEndOfLocal)
732 {
733 // Indicate we had an error and stop the decoding if so requested
734 // by the user.
735 fHandler.OnError(EventHandler::kBadEndOfLocal, endOfLocal);
736 fHadError = true;
737 if (fExitOnError) return current;
738
739 // If the user requested for us to try and recover from structure
740 // errors then we need to try locate the key in the data stream
741 // and continue decoding from there.
742 if (fTryRecover)
743 {
744 const UChar_t* searchPos = reinterpret_cast<const UChar_t*>(localStruct);
745 const UChar_t* firstLocalKey = FindKey(fgkEndOfLocal, searchPos, end);
746 const UChar_t* firstRegionalKey = FindKey(fgkEndOfReg, searchPos, end);
747
748 // If a regional key was found first, then give up on
749 // anymore local structures from this regional block and
750 // continue decoding from the next regional block.
751 // Also if the fgkEndOfLocal key was found exactly one
752 // local structure later then we should not adjust the
753 // current decoding position because it is more likely that
754 // the end of local structure key was just corrupt rather
755 // than offset.
756 if (firstLocalKey != NULL and firstRegionalKey != NULL)
757 {
758 if (firstLocalKey < firstRegionalKey)
759 {
760 size_t sizeOflocalStruct = sizeof(AliMUONLocalInfoStruct) + sizeof(UInt_t);
761 if (scalarEvent)
762 sizeOflocalStruct += sizeof(AliMUONLocalScalarsStruct);
763
764 if (firstLocalKey != current + sizeOflocalStruct)
765 current = firstLocalKey + sizeof(UInt_t);
766 }
767 else
768 {
769 // Adjust back to the start of the regional header.
770 current = firstRegionalKey - sizeof(AliMUONRegionalHeaderStruct);
771 if (scalarEvent)
772 current -= sizeof(AliMUONRegionalScalarsStruct);
773 break;
774 }
775 }
776
777 // If we could not find another good key then just continue.
778 }
779 }
780
781 fHandler.OnLocalStruct(localStruct, localScalars);
782 }
783
784 return current;
785}
786
787
788template <class EventHandler>
789const UChar_t* AliMUONTriggerDDLDecoder<EventHandler>::FindKey(
790 UInt_t key, const UChar_t* start, const UChar_t* end
791 )
792{
793 /// Searches for the first occurrence of the key value in the buffer
794 /// marked by 'start' and 'end'. 'start' should point to the start of
795 /// the buffer and 'end' should point to 'start + bufferSize'.
796 /// \param key The 32 bit word to look for.
797 /// \param start The start location to begin the search at.
798 /// \param end The pointer to the first byte just past end of the
799 /// buffer to check.
800 /// \returns The location of the first occurance of key in the buffer,
801 /// otherwise NULL is returned if nothing was found.
802
803 const UChar_t* current = start;
804 while (current + sizeof(UInt_t) <= end)
805 {
806 UInt_t data = * reinterpret_cast<const UInt_t*>(current);
807 if (data == key) return current;
808 current++;
809 }
810 return NULL;
811}
812
813#endif // ALIMUONTRIGGERDDLDECODER_H