summaryrefslogtreecommitdiff
path: root/storage/ndb/src/kernel/vm/DataBuffer.hpp
blob: 4a1df09d3dea2c08913d8dd374f049166ab7c6b1 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
/* Copyright (C) 2003 MySQL AB

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; version 2 of the License.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA */

#ifndef DATA_BUFFER_HPP
#define DATA_BUFFER_HPP

#include "ArrayPool.hpp"

/**
 * @class  DataBuffer
 * @brief  Buffer of data words
 * 
 * @note   The buffer is divided into segments (of size sz)
 */
template <Uint32 sz>
class DataBuffer {
public:
  struct Segment {
    Uint32 nextPool;
    Uint32 data[sz];
    NdbOut& print(NdbOut& out){
      out << "[DataBuffer<" << sz << ">::Segment this=" 
	  << this << dec << " nextPool= "
	  << nextPool << " ]";
      return out;
    }
  };
public:
  typedef ArrayPool<Segment> DataBufferPool;

  /**
   * Head/anchor for data buffer
   */
  struct Head {
    Head() ;

    Uint32 used;       // Words used
    Uint32 firstItem;  // First segment (or RNIL)
    Uint32 lastItem;   // Last segment (or RNIL)

    /** 
     * Get size of databuffer, in words
     */
    Uint32 getSize() const { return used;}
    
    /** 
     * Get segment size in words (template argument) 
     */
    static Uint32 getSegmentSize() { return sz;}
  };

  /** Constructor */
  DataBuffer(DataBufferPool &);

  /** Seize <b>n</b> words, Release */
  bool seize(Uint32 n);
  void release();

  /** 
   * Get size of databuffer, in words
   */
  Uint32 getSize() const;
  
  /** 
   * Check if buffer is empty
   */
  bool isEmpty() const;
  
  /**
   * Get segment size in words (template argument) 
   */
  static Uint32 getSegmentSize();
  
  void print(FILE*) const;

  /* ----------------------------------------------------------------------- */

  struct DataBufferIterator {
    Ptr<Segment>       curr;  // Ptr to current segment
    Uint32*            data;  // Pointer to current data (word)
    Uint32             ind;   // Word index within a segment
    Uint32             pos;   // Absolute word position within DataBuffer

    void print(FILE* out) {
      fprintf(out, "[DataBufferIterator curr.i=%d, data=%p, ind=%d, pos=%d]\n",
	      curr.i, (void*) data, ind, pos);
    };

    inline bool isNull() const { return curr.isNull();}
    inline void setNull() { curr.setNull(); data = 0; ind = pos = RNIL;}
  };
  typedef DataBufferIterator Iterator;

  struct ConstDataBufferIterator {
    ConstPtr<Segment>  curr;
    const Uint32 *     data;
    Uint32             ind;
    Uint32             pos;

    inline bool isNull() const { return curr.isNull();}
    inline void setNull() { curr.setNull(); data = 0; ind = pos = RNIL;}
  };

  /** 
   * Iterator 
   * @parameter hops  Number of words to jump forward
   * @note DataBuffer::next returns false if applied to last word.
   */
  bool first(DataBufferIterator &);
  bool next(DataBufferIterator &);
  bool next(DataBufferIterator &, Uint32 hops);
  bool nextPool(DataBufferIterator &);

  /**
   * Set iterator to position
   */
  bool position(DataBufferIterator& it, Uint32 pos);

  /** Iterator */
  bool first(ConstDataBufferIterator &) const;
  bool next(ConstDataBufferIterator &) const;
  bool next(ConstDataBufferIterator &, Uint32 hops) const;
  bool nextPool(ConstDataBufferIterator &) const;

  /** 
   * Returns true if it is possible to store <em>len</em> 
   * no of words at position given in iterator.
   */
  bool importable(const DataBufferIterator, Uint32 len);

  /**
   * Stores <em>len</em> no of words starting at location <em>src</em> in
   * databuffer at position given in iterator.
   * 
   * @return true if success, false otherwise.
   * @note Iterator is not advanced.
   */
  bool import(const DataBufferIterator &, const Uint32* src, Uint32 len);

  /**
   * Increases size with appends <em>len</em> words
   * @return true if success, false otherwise.
   */
  bool append(const Uint32* src, Uint32 len);

protected:
  Head head;
  DataBufferPool &  thePool;

private:
  /**
   * This is NOT a public method, since the intension is that the import
   * method using iterators will be more effective in the future 
   */
  bool import(Uint32 pos, const Uint32* src, Uint32 len);
};

template<Uint32 sz>
class LocalDataBuffer : public DataBuffer<sz> {
public:
  LocalDataBuffer(typename DataBuffer<sz>::DataBufferPool & thePool, 
		  typename DataBuffer<sz>::Head & _src)
    : DataBuffer<sz>(thePool), src(_src)
  {
    this->head = src;
  }
  
  ~LocalDataBuffer(){
    src = this->head;
  }
private:
  typename DataBuffer<sz>::Head & src;
};

template<Uint32 sz>
inline
DataBuffer<sz>::Head::Head(){
  used = 0;
  firstItem = RNIL;
  lastItem = RNIL;
}

template<Uint32 sz>
inline
bool DataBuffer<sz>::importable(const DataBufferIterator it, Uint32 len){
  return (it.pos + len < head.used);
}

template<Uint32 sz>
inline
bool DataBuffer<sz>::position(DataBufferIterator& it, Uint32 p){

  // TODO: The current implementation is not the most effective one.
  //       A more effective implementation would start at the current 
  //       position of the iterator.

  if(!first(it)){
    return false;
  }
  return next(it, p);
}
  
template<Uint32 sz>
inline
bool 
DataBuffer<sz>::import(const DataBufferIterator & it, 
		       const Uint32* src, Uint32 len){

#if 0
  DataBufferIterator it;
  position(it, _it.pos);
  
  for(; len > 0; len--){
    Uint32 s = * src;
    * it.data = s;
    next(it);
    src++;
  }
  return true;
#else
  Uint32 ind = (it.pos % sz);
  Uint32 left = sz  - ind;
  Segment * p = it.curr.p;

  while(len > left){
    memcpy(&p->data[ind], src, 4 * left);
    src += left;
    len -= left;
    ind = 0;
    left = sz;
    p = thePool.getPtr(p->nextPool);
  }
  
  memcpy(&p->data[ind], src, 4 * len);      
  return true;
#endif
}

template<Uint32 sz>
inline
bool 
DataBuffer<sz>::append(const Uint32* src, Uint32 len){
  if(len == 0)
    return true;
  
  Uint32 pos = head.used;
  if(!seize(len)){
    return false;
  }
  DataBufferIterator it;
  
  if(position(it, pos) && import(it, src, len)){
    return true;
  }
  abort();
  return false;
}

template<Uint32 sz>
inline
void DataBuffer<sz>::print(FILE* out) const {
  fprintf(out, "[DataBuffer used=%d words, segmentsize=%d words",
	  head.used, sz);

  if (head.firstItem == RNIL) {
    fprintf(out, ": No segments seized.]\n");
    return;
  } else {
    fprintf(out, "\n");
  }

  Ptr<Segment> ptr;
  ptr.i = head.firstItem;
  
  Uint32 acc = 0;
  for(; ptr.i != RNIL; ){
    thePool.getPtr(ptr);
    const Uint32 * rest = ptr.p->data;
    for(Uint32 i = 0; i<sz; i++){
      fprintf(out, " H'%.8x", rest[i]);
      if(acc++ == 6){
	acc = 0;
	fprintf(out, "\n");
      }
    }
    ptr.i = ptr.p->nextPool;
  }
  fprintf(out, " ]\n");
}

template<Uint32 sz>
inline
DataBuffer<sz>::DataBuffer(DataBufferPool & p) : thePool(p){
}

template<Uint32 sz>
inline
bool
DataBuffer<sz>::seize(Uint32 n){
  Uint32 rest; // Free space in last segment (currently)
  Segment* prevPtr;

  if(head.firstItem == RNIL){
    rest = 0;
    prevPtr = (Segment*)&head.firstItem;
  } else {
    rest = (sz - (head.used % sz)) % sz;
    prevPtr = thePool.getPtr(head.lastItem);
  }
  
  /**
   * Check for space
   */
  Uint32 free = thePool.getNoOfFree() * sz + rest;
  if(n > free){
    release();
    return false;
  }
    
  Uint32 used = head.used + n;
  Ptr<Segment> currPtr; 
  currPtr.i = head.lastItem;
  
  while(n >= sz){
    if(0)
      ndbout_c("n(%d) %c sz(%d)", n, (n>sz?'>':(n<sz?'<':'=')), sz);    

    thePool.seize(currPtr); assert(currPtr.i != RNIL);
    prevPtr->nextPool = currPtr.i;
	     
    prevPtr = currPtr.p;
    prevPtr->nextPool = RNIL;
    n -= sz;
  }
  
  if(0){
    Uint32 pos = rest + n;
    ndbout_c("rest(%d), n(%d) pos=%d %c sz(%d)", 
	     rest, n, pos, (pos>sz?'>':(pos<sz?'<':'=')), sz);
  }
  
  if(n > rest){
    thePool.seize(currPtr);
    assert(currPtr.i != RNIL);
    prevPtr->nextPool = currPtr.i;
    currPtr.p->nextPool = RNIL;
  }
  
  head.used = used;
  head.lastItem = currPtr.i;
  
#if 0
  {
    ndbout_c("Before validate - %d", head.used);
    if(head.used == 0){
      assert(head.firstItem == RNIL);
      assert(head.lastItem == RNIL);
    } else {
      Ptr<Segment> tmp;
      tmp.i = head.firstItem;
      for(Uint32 i = head.used; i > sz; i -= sz){
	ndbout << tmp.i << " ";
	tmp.p = thePool.getPtr(tmp.i);
	tmp.i = tmp.p->nextPool;
      }
      ndbout_c("%d", tmp.i);
      assert(head.lastItem == tmp.i);
    }
    ndbout_c("After validate");
  }
#endif
  return true;
}

template<Uint32 sz>
inline
void
DataBuffer<sz>::release(){
  Uint32 used = head.used + sz - 1;
  if(head.firstItem != RNIL){
    thePool.releaseList(used / sz, head.firstItem, head.lastItem);
    head.used = 0;
    head.firstItem = RNIL;
    head.lastItem = RNIL;
  }
}

template<Uint32 sz>
inline
Uint32
DataBuffer<sz>::getSegmentSize(){
  return sz;
}

template<Uint32 sz>
inline
bool
DataBuffer<sz>::first(DataBufferIterator & it){
  return first((ConstDataBufferIterator&)it);
}

template<Uint32 sz>
inline
bool
DataBuffer<sz>::next(DataBufferIterator & it){
  return next((ConstDataBufferIterator&)it);
}

template<Uint32 sz>
inline
bool
DataBuffer<sz>::next(DataBufferIterator & it, Uint32 hops){
  return next((ConstDataBufferIterator&)it, hops);
}

template<Uint32 sz>
inline
bool
DataBuffer<sz>::first(ConstDataBufferIterator & it) const {
  it.curr.i = head.firstItem;
  if(it.curr.i == RNIL){
    it.setNull();
    return false;
  }
  thePool.getPtr(it.curr);
  it.data = &it.curr.p->data[0];
  it.ind = 0;
  it.pos = 0;
  return true;
}

template<Uint32 sz>
inline
bool
DataBuffer<sz>::next(ConstDataBufferIterator & it) const {
  it.ind ++;
  it.data ++;
  it.pos ++;
  if(it.ind < sz && it.pos < head.used){
    return true;
  }

  if(it.pos < head.used){
    it.curr.i = it.curr.p->nextPool;
#ifdef ARRAY_GUARD    
    if(it.curr.i == RNIL){
      /**
       * This is actually "internal error"
       * pos can't be less than head.used and at the same time we can't 
       * find next segment
       * 
       * Note this must not "really" be checked since thePool.getPtr will
       *  abort when trying to get RNIL. That's why the check is within
       *  ARRAY_GUARD
       */
      ErrorReporter::handleAssert("DataBuffer<sz>::next", __FILE__, __LINE__);
    }
#endif
    thePool.getPtr(it.curr);
    it.data = &it.curr.p->data[0];
    it.ind = 0;
    return true;
  }
  it.setNull();
  return false;
}

template<Uint32 sz>
inline
bool
DataBuffer<sz>::next(ConstDataBufferIterator & it, Uint32 hops) const {
#if 0
  for (Uint32 i=0; i<hops; i++) {
    if (!this->next(it))
      return false;
  }
  return true;
#else
  if(it.pos + hops < head.used){
    while(hops >= sz){
      it.curr.i = it.curr.p->nextPool;
      thePool.getPtr(it.curr);
      hops -= sz;
      it.pos += sz;
    }

    it.ind += hops;
    it.pos += hops;
    if(it.ind < sz){
      it.data = &it.curr.p->data[it.ind];
      return true;
    }
    
    it.curr.i = it.curr.p->nextPool;
    thePool.getPtr(it.curr);
    it.ind -= sz;
    it.data = &it.curr.p->data[it.ind];
    return true;
  }
  it.setNull();
  return false;
#endif
}

template<Uint32 sz>
inline
Uint32
DataBuffer<sz>::getSize() const {
  return head.used;
}

template<Uint32 sz>
inline
bool
DataBuffer<sz>::isEmpty() const {
  return (head.used == 0);
}

#endif