forked from tcsh-org/tcsh
-
Notifications
You must be signed in to change notification settings - Fork 0
/
Copy pathsh.hist.c
1359 lines (1261 loc) · 37.6 KB
/
sh.hist.c
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
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
/*
* sh.hist.c: Shell history expansions and substitutions
*/
/*-
* Copyright (c) 1980, 1991 The Regents of the University of California.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include "sh.h"
#include <stdio.h> /* for rename(2), grr. */
#include <assert.h>
#include "tc.h"
#include "dotlock.h"
extern int histvalid;
extern struct Strbuf histline;
Char HistLit = 0;
static int heq (const struct wordent *, const struct wordent *);
static void hfree (struct Hist *);
#define HIST_ONLY 0x01
#define HIST_SAVE 0x02
#define HIST_LOAD 0x04
#define HIST_REV 0x08
#define HIST_CLEAR 0x10
#define HIST_MERGE 0x20
#define HIST_TIME 0x40
/*
* C shell
*/
/* Static functions don't show up in gprof summaries. So eliminate "static"
* modifier from some frequently called functions. */
#ifdef PROF
#define PG_STATIC
#else
#define PG_STATIC static
#endif
/* #define DEBUG_HIST 1 */
static const int fastMergeErase = 1;
static unsigned histCount = 0; /* number elements on history list */
static int histlen = 0;
static struct Hist *histTail = NULL; /* last element on history list */
static struct Hist *histMerg = NULL; /* last element merged by Htime */
static void insertHistHashTable(struct Hist *, unsigned);
/* Insert new element (hp) in history list after specified predecessor (pp). */
static void
hinsert(struct Hist *hp, struct Hist *pp)
{
struct Hist *fp = pp->Hnext; /* following element, if any */
hp->Hnext = fp, hp->Hprev = pp;
pp->Hnext = hp;
if (fp)
fp->Hprev = hp;
else
histTail = hp; /* meaning hp->Hnext == NULL */
histCount++;
}
/* Remove the entry from the history list. */
static void
hremove(struct Hist *hp)
{
struct Hist *pp = hp->Hprev;
assert(pp); /* elements always have a previous */
pp->Hnext = hp->Hnext;
if (hp->Hnext)
hp->Hnext->Hprev = pp;
else
histTail = pp; /* we must have been last */
if (hp == histMerg) /* deleting this hint from list */
histMerg = NULL;
assert(histCount > 0);
histCount--;
}
/* Prune length of history list to specified size by history variable. */
PG_STATIC void
discardExcess(int hlen)
{
struct Hist *hp, *np;
if (histTail == NULL) {
assert(histCount == 0);
return; /* no entries on history list */
}
/* Prune dummy entries from the front, then old entries from the back. If
* the list is still too long scan the whole list as before. But only do a
* full scan if the list is more than 6% (1/16th) too long. */
while (histCount > (unsigned)hlen && (np = Histlist.Hnext)) {
if (eventno - np->Href >= hlen || hlen == 0)
hremove(np), hfree(np);
else
break;
}
while (histCount > (unsigned)hlen && (np = histTail) != &Histlist) {
if (eventno - np->Href >= hlen || hlen == 0)
hremove(np), hfree(np);
else
break;
}
if (histCount - (hlen >> 4) <= (unsigned)hlen)
return; /* don't bother doing the full scan */
for (hp = &Histlist; histCount > (unsigned)hlen &&
(np = hp->Hnext) != NULL;)
if (eventno - np->Href >= hlen || hlen == 0)
hremove(np), hfree(np);
else
hp = np;
}
/* Add the command "sp" to the history list. */
void
savehist(
struct wordent *sp,
int mflg) /* true if -m (merge) specified */
{
/* throw away null lines */
if (sp && sp->next->word[0] == '\n')
return;
if (sp)
(void) enthist(++eventno, sp, 1, mflg, histlen);
discardExcess(histlen);
}
#define USE_JENKINS_HASH 1
/* #define USE_ONE_AT_A_TIME 1 */
#undef PRIME_LENGTH /* no need for good HTL */
#ifdef USE_JENKINS_HASH
#define hashFcnName "lookup3"
/* From:
lookup3.c, by Bob Jenkins, May 2006, Public Domain.
"... You can use this free for any purpose. It's in
the public domain. It has no warranty."
http://burtleburtle.net/bob/hash/index.html
*/
#define rot(x,k) (((x)<<(k)) | ((x)>>(32-(k))))
#define mix(a,b,c) \
{ \
a -= c; a ^= rot(c, 4); c += b; \
b -= a; b ^= rot(a, 6); a += c; \
c -= b; c ^= rot(b, 8); b += a; \
a -= c; a ^= rot(c,16); c += b; \
b -= a; b ^= rot(a,19); a += c; \
c -= b; c ^= rot(b, 4); b += a; \
}
#define final(a,b,c) \
{ \
c ^= b; c -= rot(b,14); \
a ^= c; a -= rot(c,11); \
b ^= a; b -= rot(a,25); \
c ^= b; c -= rot(b,16); \
a ^= c; a -= rot(c, 4); \
b ^= a; b -= rot(a,14); \
c ^= b; c -= rot(b,24); \
}
struct hashValue /* State used to hash a wordend word list. */
{
uint32_t a, b, c;
};
/* Set up the internal state */
static void
initializeHash(struct hashValue *h)
{
h->a = h->b = h->c = 0xdeadbeef;
}
/* This does a partial hash of the Chars in a single word. For efficiency we
* include 3 versions of the code to pack Chars into 32-bit words for the
* mixing function. */
static void
addWordToHash(struct hashValue *h, const Char *word)
{
uint32_t a = h->a, b = h->b, c = h->c;
#ifdef SHORT_STRINGS
#ifdef WIDE_STRINGS
assert(sizeof(Char) >= 4);
while (1) {
unsigned k;
if ((k = (uChar)*word++) == 0) break; a += k;
if ((k = (uChar)*word++) == 0) break; b += k;
if ((k = (uChar)*word++) == 0) break; c += k;
mix(a, b, c);
}
#else
assert(sizeof(Char) == 2);
while (1) {
unsigned k;
if ((k = (uChar)*word++) == 0) break; a += k;
if ((k = (uChar)*word++) == 0) break; a += k << 16;
if ((k = (uChar)*word++) == 0) break; b += k;
if ((k = (uChar)*word++) == 0) break; b += k << 16;
if ((k = (uChar)*word++) == 0) break; c += k;
if ((k = (uChar)*word++) == 0) break; c += k << 16;
mix(a, b, c);
}
#endif
#else
assert(sizeof(Char) == 1);
while (1) {
unsigned k;
if ((k = *word++) == 0) break; a += k;
if ((k = *word++) == 0) break; a += k << 8;
if ((k = *word++) == 0) break; a += k << 16;
if ((k = *word++) == 0) break; a += k << 24;
if ((k = *word++) == 0) break; b += k;
if ((k = *word++) == 0) break; b += k << 8;
if ((k = *word++) == 0) break; b += k << 16;
if ((k = *word++) == 0) break; b += k << 24;
if ((k = *word++) == 0) break; c += k;
if ((k = *word++) == 0) break; c += k << 8;
if ((k = *word++) == 0) break; c += k << 16;
if ((k = *word++) == 0) break; c += k << 24;
mix(a, b, c);
}
#endif
h->a = a, h->b = b, h->c = c;
}
static void
addCharToHash(struct hashValue *h, Char ch)
{
/* The compiler (gcc -O2) seems to do a good job optimizing this without
* explicitly extracting into local variables. */
h->a += (uChar)ch;
mix(h->a, h->b, h->c);
}
static uint32_t
finalizeHash(struct hashValue *h)
{
uint32_t a = h->a, b = h->b, c = h->c;
final(a, b, c);
return c;
}
#elif USE_ONE_AT_A_TIME
#define hashFcnName "one-at-a-time"
/* This one is also from Bob Jenkins, but is slower but simpler than lookup3.
"... The code given here are all public domain."
http://burtleburtle.net/bob/hash/doobs.html */
#if 0
ub4
one_at_a_time(char *key, ub4 len)
{
ub4 hash, i;
for (hash=0, i=0; i<len; ++i)
{
hash += key[i];
hash += (hash << 10);
hash ^= (hash >> 6);
}
hash += (hash << 3);
hash ^= (hash >> 11);
hash += (hash << 15);
return (hash & mask);
}
#endif
struct hashValue { uint32_t h; };
static void
initializeHash(struct hashValue *h)
{
h->h = 0;
}
static void
addWordToHash(struct hashValue *h, const Char *word)
{
unsigned k;
uint32_t hash = h->h;
while (k = (uChar)*word++)
hash += k, hash += hash << 10, hash ^= hash >> 6;
h->h = hash;
}
static void
addCharToHash(struct hashValue *h, Char c)
{
Char b[2] = { c, 0 };
addWordToHash(h, b);
}
static uint32_t
finalizeHash(struct hashValue *h)
{
unsigned hash = h->h;
hash += (hash << 3);
hash ^= (hash >> 11);
hash += (hash << 15);
return hash;
}
#else
#define hashFcnName "add-mul"
/* Simple multipy and add hash. */
#define PRIME_LENGTH 1 /* need "good" HTL */
struct hashValue { uint32_t h; };
static void
initializeHash(struct hashValue *h)
{
h->h = 0xe13e2345;
}
static void
addWordToHash(struct hashValue *h, const Char *word)
{
unsigned k;
uint32_t hash = h->h;
while (k = (uChar)*word++)
hash = hash * 0x9e4167b9 + k;
h->h = hash;
}
static void
addCharToHash(struct hashValue *h, Char c)
{
h->h = h->h * 0x9e4167b9 + (uChar)c;
}
static uint32_t
finalizeHash(struct hashValue *h)
{
return h->h;
}
#endif
static unsigned
hashhist(struct wordent *h0)
{
struct hashValue s;
struct wordent *firstWord = h0->next;
struct wordent *h = firstWord;
unsigned hash = 0;
initializeHash(&s);
for (; h != h0; h = h->next) {
if (h->word[0] == '\n')
break; /* don't hash newline */
if (h != firstWord)
addCharToHash(&s, ' '); /* space between words */
addWordToHash(&s, h->word);
}
hash = finalizeHash(&s);
/* Zero means no hash value, so never return zero as a hash value. */
return hash ? hash : 0x7fffffff; /* prime! */
}
#if 0
unsigned
hashStr(Char *str)
{
struct hashValue s;
initializeHash(&s);
addWordToHash(&s, str);
return finalizeHash(&s);
}
#endif
#ifdef PRIME_LENGTH /* need good HTL */
#define hash2tableIndex(hash, len) ((hash) % len)
#else
#define hash2tableIndex(hash, len) ((hash) & (len-1))
#endif
/* This code can be enabled to test the above hash functions for speed and
* collision avoidance. The testing is enabled by "occasional" calls to
* displayHistStats(), see which. */
#ifdef DEBUG_HIST
#ifdef BSDTIMES
static double
doTiming(int start) {
static struct timeval beginTime;
if (start) {
gettimeofday(&beginTime, NULL);
return 0.0;
} else {
struct timeval now;
gettimeofday(&now, NULL);
return (now.tv_sec-beginTime.tv_sec) +
(now.tv_usec-beginTime.tv_usec)/1e6;
}
}
#else
static double
doTiming(int start) {
USE(start);
return 0.0;
}
#endif
static void
generateHashes(int nChars, unsigned nWords, unsigned samples, unsigned *hashes,
unsigned length)
{
if (nChars < 1)
return;
nWords = (nWords < 1) ? 1 : (nWords > 4) ? 4 : nWords;
Char *number = xmalloc((nChars+nWords)*sizeof(Char));
struct wordent word[4];
struct wordent base = { NULL, &word[0], &word[0] };
word[0].word = number, word[0].next = &base, word[0].prev = &base;
unsigned w = 0; /* word number */
/* Generate multiple words of length 2, 3, 5, then all the rest. */
unsigned wBoundaries[4] = { 2-1, 2+3-1, 2+3+5-1, 0 };
/* Ensure the last word has at least 4 Chars in it. */
while (nWords >= 2 && nChars < (wBoundaries[nWords-2]+1) + 4)
nWords--;
wBoundaries[nWords-1] = 0xffffffff; /* don't end word past this point */
unsigned i;
for (i = 0; i<nChars; i++) {
/* In deference to the gawd awful add-mul hash, we won't use the worse
* case here (setting all Chars to 1), but assume mostly (or at least
* initially) ASCII data. */
number[i+w] = '!'; /* 0x21 = 33 */
if (i == wBoundaries[w]) { /* end a word here and move to next */
w++; /* next word */
number[i+w] = 0; /* terminate */
word[w].word = &number[i+w+1];
word[w].next = &base, word[w].prev = &word[w-1];
word[w-1].next = &word[w], base.prev = &word[w];
}
}
/* w is the index of the last word actually created. */
number[nChars + w] = 0; /* terminate last word */
unsigned timeLimit = !samples;
if (samples == 0)
samples = 1000000000;
doTiming(1);
double sec;
for (i = 0; i < samples; i++) {
/* increment 4 digit base 255 number; last characters vary fastest */
unsigned j = nChars-1 + w;
while (1) {
if (++number[j] != 0)
break;
/* else reset this digit and proceed to next one */
number[j] = 1;
if (&number[j] <= word[w].word)
break; /* stop at beginning of last word */
j--;
}
if (word[w].word[0] == '\n')
word[w].word[0]++; /* suppress newline character */
unsigned hash = hashhist(&base);
hashes[hash2tableIndex(hash, length)]++;
if (timeLimit && (i & 0x3ffff) == 0x3ffff) {
sec = doTiming(0);
if (sec > 10)
break;
}
}
if (i >= samples)
sec = doTiming(0);
else
samples = i; /* number we actually did */
if (sec > 0.01) {
xprintf("Hash %d (%d Char %u words) with %s: %d nsec/hash, %d mcps\n",
samples, nChars, w+1, hashFcnName, (int)((sec/samples)*1e9),
(int)((double)samples*nChars/sec/1e6));
}
}
#endif /* DEBUG_HIST */
#ifdef DEBUG_HIST
static void
testHash(void)
{
static const Char STRtestHashTimings[] =
{ 't','e','s','t','H','a','s','h','T','i','m','i','n','g','s', 0 };
struct varent *vp = adrof(STRtestHashTimings);
if (vp && vp->vec) {
unsigned hashes[4]; /* dummy place to put hashes */
Char **vals = vp->vec;
while (*vals) {
int length = getn(*vals);
unsigned words =
(length < 5) ? 1 : (length < 25) ? 2 : (length < 75) ? 3 : 4;
if (length > 0)
generateHashes(length, words, 0, hashes, 4);
vals++;
}
}
unsigned length = 1024;
#ifdef PRIME_LENGTH /* need good HTL */
length = 1021;
#endif
unsigned *hashes = xmalloc(length*sizeof(unsigned));
memset(hashes, 0, length*sizeof(unsigned));
/* Compute collision statistics for half full hashes modulo "length". */
generateHashes(4, 1, length/2, hashes, length);
/* Evaluate collisions by comparing occupancy rates (mean value 0.5).
* One bin for each number of hits. */
unsigned bins[155];
memset(bins, 0, sizeof(bins));
unsigned highest = 0;
unsigned i;
for (i = 0; i<length; i++) {
unsigned hits = hashes[i];
if (hits >= sizeof(bins)/sizeof(bins[0])) /* clip */
hits = highest = sizeof(bins)/sizeof(bins[0]) - 1;
if (hits > highest)
highest = hits;
bins[hits]++;
}
xprintf("Occupancy of %d buckets by %d hashes %d Chars %d word with %s\n",
length, length/2, 4, 1, hashFcnName);
for (i = 0; i <= highest; i++) {
xprintf(" %d buckets (%d%%) with %d hits\n",
bins[i], bins[i]*100/length, i);
}
/* Count run lengths to evaluate linear rehashing effectiveness. Estimate
* a little corrupted by edge effects. */
memset(bins, 0, sizeof(bins));
highest = 0;
for (i = 0; hashes[i] == 0; i++); /* find first occupied bucket */
unsigned run = 0;
unsigned rehashed = 0;
for (; i<length; i++) {
unsigned hits = hashes[i];
if (hits == 0 && rehashed > 0)
hits = 1 && rehashed--;
else if (hits > 1)
rehashed += hits-1;
if (hits)
run++;
else {
/* a real free slot, count it */
if (run >= sizeof(bins)/sizeof(bins[0])) /* clip */
run = highest = sizeof(bins)/sizeof(bins[0]) - 1;
if (run > highest)
highest = run;
bins[run]++;
run = 0;
}
}
/* Ignore the partial run at end as we ignored the beginning. */
double merit = 0.0, entries = 0;
for (i = 0; i <= highest; i++) {
entries += bins[i]*i; /* total hashed objects */
merit += bins[i]*i*i;
}
xprintf("Rehash collision figure of merit %u (ideal=100), run lengths:\n",
(int)(100.0*merit/entries));
for (i = 0; i <= highest; i++) {
if (bins[i] != 0)
xprintf(" %d runs of length %d buckets\n", bins[i], i);
}
xfree(hashes);
}
#endif /* DEBUG_HIST */
/* Compares two word lists for equality. */
static int
heq(const struct wordent *a0, const struct wordent *b0)
{
const struct wordent *a = a0->next, *b = b0->next;
for (;;) {
if (Strcmp(a->word, b->word) != 0)
return 0;
a = a->next;
b = b->next;
if (a == a0)
return (b == b0) ? 1 : 0;
if (b == b0)
return 0;
}
}
/* Renumber entries following p, which we will be deleting. */
PG_STATIC void
renumberHist(struct Hist *p)
{
int n = p->Href;
while ((p = p->Hnext))
p->Href = n--;
}
/* The hash table is implemented as an array of pointers to Hist entries. Each
* entry is located in the table using hash2tableIndex() and checking the
* following entries in case of a collision (linear rehash). Free entries in
* the table are zero (0, NULL, emptyHTE). Deleted entries that cannot yet be
* freed are set to one (deletedHTE). The Hist.Hhash member is non-zero iff
* the entry is in the hash table. When the hash table get too full, it is
* reallocated to be approximately twice the history length (see
* getHashTableSize). */
static struct Hist **histHashTable = NULL;
static unsigned histHashTableLength = 0; /* number of Hist pointers in table */
static struct Hist * const emptyHTE = NULL;
static struct Hist * const deletedHTE = (struct Hist *)1;
static struct {
unsigned insertCount;
unsigned removeCount;
unsigned rehashes;
int deleted;
} hashStats;
#ifdef DEBUG_HIST
void
checkHistHashTable(int print)
{
unsigned occupied = 0;
unsigned deleted = 0;
unsigned i;
for (i = 0; i<histHashTableLength; i++)
if (histHashTable[i] == emptyHTE)
continue;
else if (histHashTable[i] == deletedHTE)
deleted++;
else
occupied++;
if (print)
xprintf(" found len %u occupied %u deleted %u\n",
histHashTableLength, occupied, deleted);
assert(deleted == hashStats.deleted);
}
static int doneTest = 0;
/* Main entry point for displaying history statistics and hash function
* behavior. */
void
displayHistStats(const char *reason)
{
/* Just hash statistics for now. */
xprintf("%s history hash table len %u count %u (deleted %d)\n", reason,
histHashTableLength, histCount, hashStats.deleted);
xprintf(" inserts %u rehashes %u%% each\n",
hashStats.insertCount,
(hashStats.insertCount
? 100*hashStats.rehashes/hashStats.insertCount : 0));
xprintf(" removes %u net %u\n",
hashStats.removeCount,
hashStats.insertCount - hashStats.removeCount);
assert(hashStats.insertCount >= hashStats.removeCount);
checkHistHashTable(1);
memset(&hashStats, 0, sizeof(hashStats));
if (!doneTest) {
testHash();
doneTest = 1;
}
}
#else
void
displayHistStats(const char *reason)
{
USE(reason);
}
#endif
static void
discardHistHashTable(void)
{
if (histHashTable == NULL)
return;
displayHistStats("Discarding");
xfree(histHashTable);
histHashTable = NULL;
}
/* Computes a new hash table size, when the current one is too small. */
static unsigned
getHashTableSize(int hlen)
{
unsigned target = hlen * 2;
unsigned e = 5;
unsigned size;
while ((size = 1<<e) < target)
e++;
#ifdef PRIME_LENGTH /* need good HTL */
/* Not all prime, but most are and none have factors smaller than 11. */
return size+15;
#else
assert((size & (size-1)) == 0); /* must be a power of two */
return size;
#endif
}
/* Create the hash table or resize, if necessary. */
static void
createHistHashTable(int hlen)
{
if (hlen == 0) {
discardHistHashTable();
return;
}
if (hlen < 0) {
if (histlen <= 0)
return; /* no need for hash table */
hlen = histlen;
}
if (histHashTable != NULL) {
if (histCount < histHashTableLength * 3 / 4)
return; /* good enough for now */
discardHistHashTable(); /* too small */
}
histHashTableLength = getHashTableSize(
hlen > (int)histCount ? hlen : (int)histCount);
histHashTable = xmalloc(histHashTableLength * sizeof(struct Hist *));
memset(histHashTable, 0, histHashTableLength * sizeof(struct Hist *));
assert(histHashTable[0] == emptyHTE);
/* Now insert all the entries on the history list into the hash table. */
{
struct Hist *hp;
for (hp = &Histlist; (hp = hp->Hnext) != NULL;) {
unsigned lpHash = hashhist(&hp->Hlex);
assert(!hp->Hhash || hp->Hhash == lpHash);
hp->Hhash = 0; /* force insert to new hash table */
insertHistHashTable(hp, lpHash);
}
}
}
/* Insert np into the hash table. We assume that np is already on the
* Histlist. The specified hashval matches the new Hist entry but has not yet
* been assigned to Hhash (or the element is already on the hash table). */
static void
insertHistHashTable(struct Hist *np, unsigned hashval)
{
unsigned rehashes = 0;
unsigned hi = 0;
if (!histHashTable)
return;
if (np->Hhash != 0) {
/* already in hash table */
assert(hashval == np->Hhash);
return;
}
assert(np != deletedHTE);
/* Find a free (empty or deleted) slot, using linear rehash. */
assert(histHashTable);
for (rehashes = 0;
((hi = hash2tableIndex(hashval + rehashes, histHashTableLength)),
histHashTable[hi] != emptyHTE && histHashTable[hi] != deletedHTE);
rehashes++) {
assert(np != histHashTable[hi]);
if (rehashes >= histHashTableLength / 10) {
/* Hash table is full, so grow it. We assume the create function
* will roughly double the size we give it. Create initializes the
* new table with everything on the Histlist, so we are done when
* it returns. */
#ifdef DEBUG_HIST
xprintf("Growing history hash table from %d ...",
histHashTableLength);
flush();
#endif
discardHistHashTable();
createHistHashTable(histHashTableLength);
#ifdef DEBUG_HIST
xprintf("to %d.\n", histHashTableLength);
#endif
return;
}
}
/* Might be sensible to grow hash table if rehashes is "too big" here. */
if (histHashTable[hi] == deletedHTE)
hashStats.deleted--;
histHashTable[hi] = np;
np->Hhash = hashval;
hashStats.insertCount++;
hashStats.rehashes += rehashes;
}
/* Remove the 'np' entry from the hash table. */
static void
removeHistHashTable(struct Hist *np)
{
unsigned hi = np->Hhash;
if (!histHashTable || !hi)
return; /* no hash table or not on it */
/* find desired entry */
while ((hi = hash2tableIndex(hi, histHashTableLength)),
histHashTable[hi] != emptyHTE) {
if (np == histHashTable[hi]) {
unsigned i;
unsigned deletes = 0;
histHashTable[hi] = deletedHTE; /* dummy, but non-zero entry */
/* now peek ahead to see if the dummies are really necessary. */
i = 1;
while (histHashTable[hash2tableIndex(hi+i, histHashTableLength)] ==
deletedHTE)
i++;
if (histHashTable[hash2tableIndex(hi+i, histHashTableLength)] ==
emptyHTE) {
/* dummies are no longer necessary placeholders. */
deletes = i;
while (i-- > 0) {
histHashTable[hash2tableIndex(hi+i, histHashTableLength)] =
emptyHTE;
}
}
hashStats.deleted += 1 - deletes; /* delta deleted entries */
hashStats.removeCount++;
return;
}
hi++; /* linear rehash */
}
assert(!"Hist entry not found in hash table");
}
/* Search the history hash table for a command matching lp, using hashval as
* its hash value. */
static struct Hist *
findHistHashTable(struct wordent *lp, unsigned hashval)
{
unsigned deleted = 0; /* number of deleted entries skipped */
unsigned hi = hashval;
struct Hist *hp;
if (!histHashTable)
return NULL;
while ((hi = hash2tableIndex(hi, histHashTableLength)),
(hp = histHashTable[hi]) != emptyHTE) {
if (hp == deletedHTE)
deleted++;
else if (hp->Hhash == hashval && heq(lp, &(hp->Hlex)))
return hp;
if (deleted > (histHashTableLength>>4)) {
/* lots of deletes, so we need a sparser table. */
discardHistHashTable();
createHistHashTable(histHashTableLength);
return findHistHashTable(lp, hashval);
}
hi++; /* linear rehash */
}
return NULL;
}
/* When merge semantics are in use, find the approximate predecessor for the
* new entry, so that the Htime entries are decreasing. Return the entry just
* before the first entry with equal times, so the caller can check for
* duplicates. When pTime is not NULL, use it as a starting point for search,
* otherwise search from beginning (largest time value) of history list. */
PG_STATIC struct Hist *
mergeInsertionPoint(
struct Hist *np, /* new entry to be inserted */
struct Hist *pTime) /* hint about where to insert */
{
struct Hist *pp, *p;
if (histTail && histTail->Htime >= np->Htime)
pTime = histTail; /* new entry goes at the end */
if (histMerg && histMerg != &Histlist && histMerg != Histlist.Hnext) {
/* Check above and below previous insertion point, in case we're adding
* sequential times in the middle of the list (e.g. history -M). */
if (histMerg->Htime >= np->Htime)
pTime = histMerg;
else if (histMerg->Hprev->Htime >= np->Htime)
pTime = histMerg->Hprev;
}
if (pTime) {
/* With hint, search up the list until Htime is greater. We skip past
* the equal ones, too, so our caller can elide duplicates. */
pp = pTime;
while (pp != &Histlist && pp->Htime <= np->Htime)
pp = pp->Hprev;
} else
pp = &Histlist;
/* Search down the list while current entry's time is too large. */
while ((p = pp->Hnext) && (p->Htime > np->Htime))
pp = p; /* advance insertion point */
/* Remember recent position as hint for next time */
histMerg = pp;
return pp;
}
/* Bubble Hnum & Href in new entry down to pp through earlier part of list. */
PG_STATIC void bubbleHnumHrefDown(struct Hist *np, struct Hist *pp)
{
struct Hist *p;
for (p = Histlist.Hnext; p != pp->Hnext; p = p->Hnext) {
/* swap Hnum & Href values of p and np. */
int n = p->Hnum, r = p->Href;
p->Hnum = np->Hnum; p->Href = np->Href;
np->Hnum = n; np->Href = r;
}
}
/* Enter new command into the history list according to current settings. */
struct Hist *
enthist(
int event, /* newly incremented global eventno */
struct wordent *lp,
int docopy,
int mflg, /* true if merge requested */
int hlen) /* -1 if unknown */
{
struct Hist *p = NULL, *pp = &Histlist, *pTime = NULL;
struct Hist *np;
const Char *dp;
unsigned lpHash = 0; /* non-zero if hashing entries */
if ((dp = varval(STRhistdup)) != STRNULL) {
if (eq(dp, STRerase)) {
/* [email protected] (Kobayashi Masaoki) */
createHistHashTable(hlen);
lpHash = hashhist(lp);
assert(lpHash != 0);
p = findHistHashTable(lp, lpHash);
if (p) {
if (Htime != 0 && p->Htime > Htime)
Htime = p->Htime;
/* If we are merging, and the old entry is at the place we want
* to insert the new entry, then remember the place. */
if (mflg && Htime != 0 && p->Hprev->Htime >= Htime)
pTime = p->Hprev;
if (!fastMergeErase)
renumberHist(p); /* Reset Href of subsequent entries */
hremove(p);
hfree(p);
p = NULL; /* so new entry is allocated below */
}
}
else if (eq(dp, STRall)) {
createHistHashTable(hlen);
lpHash = hashhist(lp);
assert(lpHash != 0);
p = findHistHashTable(lp, lpHash);
if (p) /* p!=NULL, only update this entry's Htime below */
eventno--; /* not adding a new event */
}
else if (eq(dp, STRprev)) {
if (pp->Hnext && heq(lp, &(pp->Hnext->Hlex))) {
p = pp->Hnext;
eventno--;
}
}
}
np = p ? p : xmalloc(sizeof(*np));
/* Pick up timestamp set by lex() in Htime if reading saved history */
if (Htime != 0) {
np->Htime = Htime;
Htime = 0;
}
else
(void) time(&(np->Htime));
if (p == np)
return np; /* reused existing entry */
/* Initialize the new entry. */
np->Hnum = np->Href = event;
if (docopy) {
copylex(&np->Hlex, lp);
if (histvalid)
np->histline = Strsave(histline.s);
else
np->histline = NULL;
}
else {
np->Hlex.next = lp->next;
lp->next->prev = &np->Hlex;
np->Hlex.prev = lp->prev;
lp->prev->next = &np->Hlex;
np->histline = NULL;
}
np->Hhash = 0;
/* The head of history list is the default insertion point.
If merging, advance insertion point, in pp, according to Htime. */
/* XXX -- In histdup=all, Htime values can be non-monotonic. */