Coverage Report

Created: 2025-08-26 06:41

/src/libxml2/timsort.h
Line
Count
Source (jump to first uncovered line)
1
/*
2
 * Taken from https://github.com/swenson/sort
3
 * Revision: 05fd77bfec049ce8b7c408c4d3dd2d51ee061a15
4
 * Removed all code unrelated to Timsort and made minor adjustments for
5
 * cross-platform compatibility.
6
 */
7
8
/*
9
 * The MIT License (MIT)
10
 *
11
 * Copyright (c) 2010-2017 Christopher Swenson.
12
 * Copyright (c) 2012 Vojtech Fried.
13
 * Copyright (c) 2012 Google Inc. All Rights Reserved.
14
 *
15
 * Permission is hereby granted, free of charge, to any person obtaining a
16
 * copy of this software and associated documentation files (the "Software"),
17
 * to deal in the Software without restriction, including without limitation
18
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
19
 * and/or sell copies of the Software, and to permit persons to whom the
20
 * Software is furnished to do so, subject to the following conditions:
21
 *
22
 * The above copyright notice and this permission notice shall be included in
23
 * all copies or substantial portions of the Software.
24
 *
25
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
26
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
27
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
28
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
29
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
30
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
31
 * DEALINGS IN THE SOFTWARE.
32
 */
33
34
#include <stdlib.h>
35
#include <stdio.h>
36
#include <string.h>
37
#ifdef HAVE_STDINT_H
38
#include <stdint.h>
39
#elif defined(_WIN32)
40
typedef unsigned __int64 uint64_t;
41
#endif
42
43
#ifndef SORT_NAME
44
#error "Must declare SORT_NAME"
45
#endif
46
47
#ifndef SORT_TYPE
48
#error "Must declare SORT_TYPE"
49
#endif
50
51
#ifndef SORT_CMP
52
#define SORT_CMP(x, y)  ((x) < (y) ? -1 : ((x) == (y) ? 0 : 1))
53
#endif
54
55
#ifndef TIM_SORT_STACK_SIZE
56
#define TIM_SORT_STACK_SIZE 128
57
#endif
58
59
12.2k
#define SORT_SWAP(x,y) {SORT_TYPE __SORT_SWAP_t = (x); (x) = (y); (y) = __SORT_SWAP_t;}
60
61
62
/* Common, type-agnostic functions and constants that we don't want to declare twice. */
63
#ifndef SORT_COMMON_H
64
#define SORT_COMMON_H
65
66
#ifndef MAX
67
37.5k
#define MAX(x,y) (((x) > (y) ? (x) : (y)))
68
#endif
69
70
#ifndef MIN
71
65.6k
#define MIN(x,y) (((x) < (y) ? (x) : (y)))
72
#endif
73
74
static int compute_minrun(const uint64_t);
75
76
#ifndef CLZ
77
#if defined(__GNUC__) && ((__GNUC__ == 3 && __GNUC_MINOR__ >= 4) || (__GNUC__ > 3))
78
37.5k
#define CLZ __builtin_clzll
79
#else
80
81
static int clzll(uint64_t);
82
83
/* adapted from Hacker's Delight */
84
static int clzll(uint64_t x) {
85
  int n;
86
87
  if (x == 0) {
88
    return 64;
89
  }
90
91
  n = 0;
92
93
  if (x <= 0x00000000FFFFFFFFL) {
94
    n = n + 32;
95
    x = x << 32;
96
  }
97
98
  if (x <= 0x0000FFFFFFFFFFFFL) {
99
    n = n + 16;
100
    x = x << 16;
101
  }
102
103
  if (x <= 0x00FFFFFFFFFFFFFFL) {
104
    n = n + 8;
105
    x = x << 8;
106
  }
107
108
  if (x <= 0x0FFFFFFFFFFFFFFFL) {
109
    n = n + 4;
110
    x = x << 4;
111
  }
112
113
  if (x <= 0x3FFFFFFFFFFFFFFFL) {
114
    n = n + 2;
115
    x = x << 2;
116
  }
117
118
  if (x <= 0x7FFFFFFFFFFFFFFFL) {
119
    n = n + 1;
120
  }
121
122
  return n;
123
}
124
125
#define CLZ clzll
126
#endif
127
#endif
128
129
37.5k
static __inline int compute_minrun(const uint64_t size) {
130
37.5k
  const int top_bit = 64 - CLZ(size);
131
37.5k
  const int shift = MAX(top_bit, 6) - 6;
132
37.5k
  const int minrun = size >> shift;
133
37.5k
  const uint64_t mask = (1ULL << shift) - 1;
134
135
37.5k
  if (mask & size) {
136
13.5k
    return minrun + 1;
137
13.5k
  }
138
139
24.0k
  return minrun;
140
37.5k
}
141
142
#endif /* SORT_COMMON_H */
143
144
1.46M
#define SORT_CONCAT(x, y) x ## _ ## y
145
1.46M
#define SORT_MAKE_STR1(x, y) SORT_CONCAT(x,y)
146
1.46M
#define SORT_MAKE_STR(x) SORT_MAKE_STR1(SORT_NAME,x)
147
148
935k
#define BINARY_INSERTION_FIND          SORT_MAKE_STR(binary_insertion_find)
149
144k
#define BINARY_INSERTION_SORT_START    SORT_MAKE_STR(binary_insertion_sort_start)
150
104k
#define BINARY_INSERTION_SORT          SORT_MAKE_STR(binary_insertion_sort)
151
8.45k
#define REVERSE_ELEMENTS               SORT_MAKE_STR(reverse_elements)
152
103k
#define COUNT_RUN                      SORT_MAKE_STR(count_run)
153
23.8k
#define CHECK_INVARIANT                SORT_MAKE_STR(check_invariant)
154
#define TIM_SORT                       SORT_MAKE_STR(tim_sort)
155
65.6k
#define TIM_SORT_RESIZE                SORT_MAKE_STR(tim_sort_resize)
156
65.6k
#define TIM_SORT_MERGE                 SORT_MAKE_STR(tim_sort_merge)
157
9.93k
#define TIM_SORT_COLLAPSE              SORT_MAKE_STR(tim_sort_collapse)
158
159
#ifndef MAX
160
#define MAX(x,y) (((x) > (y) ? (x) : (y)))
161
#endif
162
#ifndef MIN
163
#define MIN(x,y) (((x) < (y) ? (x) : (y)))
164
#endif
165
166
typedef struct {
167
  size_t start;
168
  size_t length;
169
} TIM_SORT_RUN_T;
170
171
172
XML_HIDDEN
173
void BINARY_INSERTION_SORT(SORT_TYPE *dst, const size_t size);
174
XML_HIDDEN
175
void TIM_SORT(SORT_TYPE *dst, const size_t size);
176
177
178
/* Function used to do a binary search for binary insertion sort */
179
static __inline size_t BINARY_INSERTION_FIND(SORT_TYPE *dst, const SORT_TYPE x,
180
935k
    const size_t size) {
181
935k
  size_t l, c, r;
182
935k
  SORT_TYPE cx;
183
935k
  l = 0;
184
935k
  r = size - 1;
185
935k
  c = r >> 1;
186
187
  /* check for out of bounds at the beginning. */
188
935k
  if (SORT_CMP(x, dst[0]) < 0) {
189
64.2k
    return 0;
190
871k
  } else if (SORT_CMP(x, dst[r]) > 0) {
191
0
    return r;
192
0
  }
193
194
871k
  cx = dst[c];
195
196
3.65M
  while (1) {
197
3.65M
    const int val = SORT_CMP(x, cx);
198
199
3.65M
    if (val < 0) {
200
739k
      if (c - l <= 1) {
201
217k
        return c;
202
217k
      }
203
204
521k
      r = c;
205
2.91M
    } else { /* allow = for stability. The binary search favors the right. */
206
2.91M
      if (r - c <= 1) {
207
653k
        return c + 1;
208
653k
      }
209
210
2.26M
      l = c;
211
2.26M
    }
212
213
2.78M
    c = l + ((r - l) >> 1);
214
2.78M
    cx = dst[c];
215
2.78M
  }
216
871k
}
217
218
/* Binary insertion sort, but knowing that the first "start" entries are sorted.  Used in timsort. */
219
144k
static void BINARY_INSERTION_SORT_START(SORT_TYPE *dst, const size_t start, const size_t size) {
220
144k
  size_t i;
221
222
3.09M
  for (i = start; i < size; i++) {
223
2.95M
    size_t j;
224
2.95M
    SORT_TYPE x;
225
2.95M
    size_t location;
226
227
    /* If this entry is already correct, just move along */
228
2.95M
    if (SORT_CMP(dst[i - 1], dst[i]) <= 0) {
229
2.01M
      continue;
230
2.01M
    }
231
232
    /* Else we need to find the right place, shift everything over, and squeeze in */
233
935k
    x = dst[i];
234
935k
    location = BINARY_INSERTION_FIND(dst, x, i);
235
236
6.36M
    for (j = i - 1; j >= location; j--) {
237
5.49M
      dst[j + 1] = dst[j];
238
239
5.49M
      if (j == 0) { /* check edge case because j is unsigned */
240
64.2k
        break;
241
64.2k
      }
242
5.49M
    }
243
244
935k
    dst[location] = x;
245
935k
  }
246
144k
}
247
248
/* Binary insertion sort */
249
104k
void BINARY_INSERTION_SORT(SORT_TYPE *dst, const size_t size) {
250
  /* don't bother sorting an array of size <= 1 */
251
104k
  if (size <= 1) {
252
0
    return;
253
0
  }
254
255
104k
  BINARY_INSERTION_SORT_START(dst, 1, size);
256
104k
}
257
258
/* timsort implementation, based on timsort.txt */
259
260
8.45k
static __inline void REVERSE_ELEMENTS(SORT_TYPE *dst, size_t start, size_t end) {
261
19.2k
  while (1) {
262
19.2k
    if (start >= end) {
263
8.45k
      return;
264
8.45k
    }
265
266
10.8k
    SORT_SWAP(dst[start], dst[end]);
267
10.8k
    start++;
268
10.8k
    end--;
269
10.8k
  }
270
8.45k
}
271
272
103k
static size_t COUNT_RUN(SORT_TYPE *dst, const size_t start, const size_t size) {
273
103k
  size_t curr;
274
275
103k
  if (size - start == 1) {
276
16.2k
    return 1;
277
16.2k
  }
278
279
86.9k
  if (start >= size - 2) {
280
2.02k
    if (SORT_CMP(dst[size - 2], dst[size - 1]) > 0) {
281
1.41k
      SORT_SWAP(dst[size - 2], dst[size - 1]);
282
1.41k
    }
283
284
2.02k
    return 2;
285
2.02k
  }
286
287
84.9k
  curr = start + 2;
288
289
84.9k
  if (SORT_CMP(dst[start], dst[start + 1]) <= 0) {
290
    /* increasing run */
291
7.29M
    while (1) {
292
7.29M
      if (curr == size - 1) {
293
23.4k
        break;
294
23.4k
      }
295
296
7.26M
      if (SORT_CMP(dst[curr - 1], dst[curr]) > 0) {
297
53.0k
        break;
298
53.0k
      }
299
300
7.21M
      curr++;
301
7.21M
    }
302
303
76.4k
    return curr - start;
304
76.4k
  } else {
305
    /* decreasing run */
306
14.9k
    while (1) {
307
14.9k
      if (curr == size - 1) {
308
2.64k
        break;
309
2.64k
      }
310
311
12.2k
      if (SORT_CMP(dst[curr - 1], dst[curr]) <= 0) {
312
5.81k
        break;
313
5.81k
      }
314
315
6.45k
      curr++;
316
6.45k
    }
317
318
    /* reverse in-place */
319
8.45k
    REVERSE_ELEMENTS(dst, start, curr - 1);
320
8.45k
    return curr - start;
321
8.45k
  }
322
84.9k
}
323
324
23.8k
static int CHECK_INVARIANT(TIM_SORT_RUN_T *stack, const int stack_curr) {
325
23.8k
  size_t A, B, C;
326
327
23.8k
  if (stack_curr < 2) {
328
2.70k
    return 1;
329
2.70k
  }
330
331
21.1k
  if (stack_curr == 2) {
332
7.54k
    const size_t A1 = stack[stack_curr - 2].length;
333
7.54k
    const size_t B1 = stack[stack_curr - 1].length;
334
335
7.54k
    if (A1 <= B1) {
336
200
      return 0;
337
200
    }
338
339
7.34k
    return 1;
340
7.54k
  }
341
342
13.6k
  A = stack[stack_curr - 3].length;
343
13.6k
  B = stack[stack_curr - 2].length;
344
13.6k
  C = stack[stack_curr - 1].length;
345
346
13.6k
  if ((A <= B + C) || (B <= C)) {
347
9.73k
    return 0;
348
9.73k
  }
349
350
3.89k
  return 1;
351
13.6k
}
352
353
typedef struct {
354
  size_t alloc;
355
  SORT_TYPE *storage;
356
} TEMP_STORAGE_T;
357
358
65.6k
static void TIM_SORT_RESIZE(TEMP_STORAGE_T *store, const size_t new_size) {
359
65.6k
  if (store->alloc < new_size) {
360
54.4k
    SORT_TYPE *tempstore = (SORT_TYPE *)realloc(store->storage, new_size * sizeof(SORT_TYPE));
361
362
54.4k
    if (tempstore == NULL) {
363
0
      fprintf(stderr, "Error allocating temporary storage for tim sort: need %lu bytes",
364
0
              (unsigned long)(sizeof(SORT_TYPE) * new_size));
365
0
      exit(1);
366
0
    }
367
368
54.4k
    store->storage = tempstore;
369
54.4k
    store->alloc = new_size;
370
54.4k
  }
371
65.6k
}
372
373
static void TIM_SORT_MERGE(SORT_TYPE *dst, const TIM_SORT_RUN_T *stack, const int stack_curr,
374
65.6k
                           TEMP_STORAGE_T *store) {
375
65.6k
  const size_t A = stack[stack_curr - 2].length;
376
65.6k
  const size_t B = stack[stack_curr - 1].length;
377
65.6k
  const size_t curr = stack[stack_curr - 2].start;
378
65.6k
  SORT_TYPE *storage;
379
65.6k
  size_t i, j, k;
380
65.6k
  TIM_SORT_RESIZE(store, MIN(A, B));
381
65.6k
  storage = store->storage;
382
383
  /* left merge */
384
65.6k
  if (A < B) {
385
11.4k
    memcpy(storage, &dst[curr], A * sizeof(SORT_TYPE));
386
11.4k
    i = 0;
387
11.4k
    j = curr + A;
388
389
1.79M
    for (k = curr; k < curr + A + B; k++) {
390
1.79M
      if ((i < A) && (j < curr + A + B)) {
391
1.36M
        if (SORT_CMP(storage[i], dst[j]) <= 0) {
392
264k
          dst[k] = storage[i++];
393
1.10M
        } else {
394
1.10M
          dst[k] = dst[j++];
395
1.10M
        }
396
1.36M
      } else if (i < A) {
397
422k
        dst[k] = storage[i++];
398
422k
      } else {
399
3.73k
        break;
400
3.73k
      }
401
1.79M
    }
402
54.1k
  } else {
403
    /* right merge */
404
54.1k
    memcpy(storage, &dst[curr + A], B * sizeof(SORT_TYPE));
405
54.1k
    i = B;
406
54.1k
    j = curr + A;
407
54.1k
    k = curr + A + B;
408
409
5.66M
    while (k > curr) {
410
5.63M
      k--;
411
5.63M
      if ((i > 0) && (j > curr)) {
412
4.39M
        if (SORT_CMP(dst[j - 1], storage[i - 1]) > 0) {
413
4.20M
          dst[k] = dst[--j];
414
4.20M
        } else {
415
198k
          dst[k] = storage[--i];
416
198k
        }
417
4.39M
      } else if (i > 0) {
418
1.21M
        dst[k] = storage[--i];
419
1.21M
      } else {
420
19.2k
        break;
421
19.2k
      }
422
5.63M
    }
423
54.1k
  }
424
65.6k
}
425
426
static int TIM_SORT_COLLAPSE(SORT_TYPE *dst, TIM_SORT_RUN_T *stack, int stack_curr,
427
9.93k
                             TEMP_STORAGE_T *store, const size_t size) {
428
20.6k
  while (1) {
429
20.6k
    size_t A, B, C, D;
430
20.6k
    int ABC, BCD, CD;
431
432
    /* if the stack only has one thing on it, we are done with the collapse */
433
20.6k
    if (stack_curr <= 1) {
434
0
      break;
435
0
    }
436
437
    /* if this is the last merge, just do it */
438
20.6k
    if ((stack_curr == 2) && (stack[0].length + stack[1].length == size)) {
439
0
      TIM_SORT_MERGE(dst, stack, stack_curr, store);
440
0
      stack[0].length += stack[1].length;
441
0
      stack_curr--;
442
0
      break;
443
0
    }
444
    /* check if the invariant is off for a stack of 2 elements */
445
20.6k
    else if ((stack_curr == 2) && (stack[0].length <= stack[1].length)) {
446
2.70k
      TIM_SORT_MERGE(dst, stack, stack_curr, store);
447
2.70k
      stack[0].length += stack[1].length;
448
2.70k
      stack_curr--;
449
2.70k
      break;
450
17.9k
    } else if (stack_curr == 2) {
451
6.23k
      break;
452
6.23k
    }
453
454
11.6k
    B = stack[stack_curr - 3].length;
455
11.6k
    C = stack[stack_curr - 2].length;
456
11.6k
    D = stack[stack_curr - 1].length;
457
458
11.6k
    if (stack_curr >= 4) {
459
1.93k
      A = stack[stack_curr - 4].length;
460
1.93k
      ABC = (A <= B + C);
461
9.73k
    } else {
462
9.73k
      ABC = 0;
463
9.73k
    }
464
465
11.6k
    BCD = (B <= C + D) || ABC;
466
11.6k
    CD = (C <= D);
467
468
    /* Both invariants are good */
469
11.6k
    if (!BCD && !CD) {
470
993
      break;
471
993
    }
472
473
    /* left merge */
474
10.6k
    if (BCD && !CD) {
475
3.31k
      TIM_SORT_MERGE(dst, stack, stack_curr - 1, store);
476
3.31k
      stack[stack_curr - 3].length += stack[stack_curr - 2].length;
477
3.31k
      stack[stack_curr - 2] = stack[stack_curr - 1];
478
3.31k
      stack_curr--;
479
7.36k
    } else {
480
      /* right merge */
481
7.36k
      TIM_SORT_MERGE(dst, stack, stack_curr, store);
482
7.36k
      stack[stack_curr - 2].length += stack[stack_curr - 1].length;
483
7.36k
      stack_curr--;
484
7.36k
    }
485
10.6k
  }
486
487
9.93k
  return stack_curr;
488
9.93k
}
489
490
static __inline int PUSH_NEXT(SORT_TYPE *dst,
491
                              const size_t size,
492
                              TEMP_STORAGE_T *store,
493
                              const size_t minrun,
494
                              TIM_SORT_RUN_T *run_stack,
495
                              size_t *stack_curr,
496
103k
                              size_t *curr) {
497
103k
  size_t len = COUNT_RUN(dst, *curr, size);
498
103k
  size_t run = minrun;
499
500
103k
  if (run > size - *curr) {
501
34.6k
    run = size - *curr;
502
34.6k
  }
503
504
103k
  if (run > len) {
505
39.3k
    BINARY_INSERTION_SORT_START(&dst[*curr], len, run);
506
39.3k
    len = run;
507
39.3k
  }
508
509
103k
  run_stack[*stack_curr].start = *curr;
510
103k
  run_stack[*stack_curr].length = len;
511
103k
  (*stack_curr)++;
512
103k
  *curr += len;
513
514
103k
  if (*curr == size) {
515
    /* finish up */
516
89.8k
    while (*stack_curr > 1) {
517
52.2k
      TIM_SORT_MERGE(dst, run_stack, *stack_curr, store);
518
52.2k
      run_stack[*stack_curr - 2].length += run_stack[*stack_curr - 1].length;
519
52.2k
      (*stack_curr)--;
520
52.2k
    }
521
522
37.5k
    if (store->storage != NULL) {
523
37.5k
      free(store->storage);
524
37.5k
      store->storage = NULL;
525
37.5k
    }
526
527
37.5k
    return 0;
528
37.5k
  }
529
530
65.6k
  return 1;
531
103k
}
532
533
142k
void TIM_SORT(SORT_TYPE *dst, const size_t size) {
534
142k
  size_t minrun;
535
142k
  TEMP_STORAGE_T _store, *store;
536
142k
  TIM_SORT_RUN_T run_stack[TIM_SORT_STACK_SIZE];
537
142k
  size_t stack_curr = 0;
538
142k
  size_t curr = 0;
539
540
  /* don't bother sorting an array of size 1 */
541
142k
  if (size <= 1) {
542
0
    return;
543
0
  }
544
545
142k
  if (size < 64) {
546
104k
    BINARY_INSERTION_SORT(dst, size);
547
104k
    return;
548
104k
  }
549
550
  /* compute the minimum run length */
551
37.5k
  minrun = compute_minrun(size);
552
  /* temporary storage for merges */
553
37.5k
  store = &_store;
554
37.5k
  store->alloc = 0;
555
37.5k
  store->storage = NULL;
556
557
37.5k
  if (!PUSH_NEXT(dst, size, store, minrun, run_stack, &stack_curr, &curr)) {
558
0
    return;
559
0
  }
560
561
37.5k
  if (!PUSH_NEXT(dst, size, store, minrun, run_stack, &stack_curr, &curr)) {
562
23.4k
    return;
563
23.4k
  }
564
565
14.1k
  if (!PUSH_NEXT(dst, size, store, minrun, run_stack, &stack_curr, &curr)) {
566
7.57k
    return;
567
7.57k
  }
568
569
23.8k
  while (1) {
570
23.8k
    if (!CHECK_INVARIANT(run_stack, stack_curr)) {
571
9.93k
      stack_curr = TIM_SORT_COLLAPSE(dst, run_stack, stack_curr, store, size);
572
9.93k
      continue;
573
9.93k
    }
574
575
13.9k
    if (!PUSH_NEXT(dst, size, store, minrun, run_stack, &stack_curr, &curr)) {
576
6.57k
      return;
577
6.57k
    }
578
13.9k
  }
579
6.57k
}
580
581
#undef SORT_CONCAT
582
#undef SORT_MAKE_STR1
583
#undef SORT_MAKE_STR
584
#undef SORT_NAME
585
#undef SORT_TYPE
586
#undef SORT_CMP
587
#undef TEMP_STORAGE_T
588
#undef TIM_SORT_RUN_T
589
#undef PUSH_NEXT
590
#undef SORT_SWAP
591
#undef SORT_CONCAT
592
#undef SORT_MAKE_STR1
593
#undef SORT_MAKE_STR
594
#undef BINARY_INSERTION_FIND
595
#undef BINARY_INSERTION_SORT_START
596
#undef BINARY_INSERTION_SORT
597
#undef REVERSE_ELEMENTS
598
#undef COUNT_RUN
599
#undef TIM_SORT
600
#undef TIM_SORT_RESIZE
601
#undef TIM_SORT_COLLAPSE
602
#undef TIM_SORT_RUN_T
603
#undef TEMP_STORAGE_T