Asterisk - The Open Source Telephony Project  GIT-master-b7027de
hash_page.c
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1 /*-
2  * Copyright (c) 1990, 1993, 1994
3  * The Regents of the University of California. All rights reserved.
4  *
5  * This code is derived from software contributed to Berkeley by
6  * Margo Seltzer.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  * notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  * notice, this list of conditions and the following disclaimer in the
15  * documentation and/or other materials provided with the distribution.
16  * 3. All advertising materials mentioning features or use of this software
17  * must display the following acknowledgement:
18  * This product includes software developed by the University of
19  * California, Berkeley and its contributors.
20  * 4. Neither the name of the University nor the names of its contributors
21  * may be used to endorse or promote products derived from this software
22  * without specific prior written permission.
23  *
24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27  * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34  * SUCH DAMAGE.
35  */
36 
37 #if defined(LIBC_SCCS) && !defined(lint)
38 static char sccsid[] = "@(#)hash_page.c 8.7 (Berkeley) 8/16/94";
39 #endif /* LIBC_SCCS and not lint */
40 
41 /*
42  * PACKAGE: hashing
43  *
44  * DESCRIPTION:
45  * Page manipulation for hashing package.
46  *
47  * ROUTINES:
48  *
49  * External
50  * __get_page
51  * __add_ovflpage
52  * Internal
53  * overflow_page
54  * open_temp
55  */
56 
57 #include <sys/types.h>
58 
59 #include <errno.h>
60 #include <fcntl.h>
61 #include <signal.h>
62 #include <stdio.h>
63 #include <stdlib.h>
64 #include <string.h>
65 #include <unistd.h>
66 #ifdef DEBUG
67 #include <assert.h>
68 #endif
69 
70 #include "../include/db.h"
71 #include "hash.h"
72 #include "page.h"
73 #include "extern.h"
74 
75 static u_int32_t *fetch_bitmap __P((HTAB *, int));
77 static int open_temp __P((HTAB *));
78 static u_int16_t overflow_page __P((HTAB *));
79 static void putpair __P((char *, const DBT *, const DBT *));
80 static void squeeze_key __P((u_int16_t *, const DBT *, const DBT *));
81 static int ugly_split
82  __P((HTAB *, u_int32_t, BUFHEAD *, BUFHEAD *, int, int));
83 
84 #define PAGE_INIT(P) { \
85  ((u_int16_t *)(P))[0] = 0; \
86  ((u_int16_t *)(P))[1] = hashp->BSIZE - 3 * sizeof(u_int16_t); \
87  ((u_int16_t *)(P))[2] = hashp->BSIZE; \
88 }
89 
90 /*
91  * This is called AFTER we have verified that there is room on the page for
92  * the pair (PAIRFITS has returned true) so we go right ahead and start moving
93  * stuff on.
94  */
95 static void
96 putpair(p, key, val)
97  char *p;
98  const DBT *key, *val;
99 {
100  register u_int16_t *bp, n, off;
101 
102  bp = (u_int16_t *)p;
103 
104  /* Enter the key first. */
105  n = bp[0];
106 
107  off = OFFSET(bp) - key->size;
108  memmove(p + off, key->data, key->size);
109  bp[++n] = off;
110 
111  /* Now the data. */
112  off -= val->size;
113  memmove(p + off, val->data, val->size);
114  bp[++n] = off;
115 
116  /* Adjust page info. */
117  bp[0] = n;
118  bp[n + 1] = off - ((n + 3) * sizeof(u_int16_t));
119  bp[n + 2] = off;
120 }
121 
122 /*
123  * Returns:
124  * 0 OK
125  * -1 error
126  */
127 extern int
128 __delpair(hashp, bufp, ndx)
129  HTAB *hashp;
130  BUFHEAD *bufp;
131  register int ndx;
132 {
133  register u_int16_t *bp, newoff;
134  register int n;
135  u_int16_t pairlen;
136 
137  bp = (u_int16_t *)bufp->page;
138  n = bp[0];
139 
140  if (bp[ndx + 1] < REAL_KEY)
141  return (__big_delete(hashp, bufp));
142  if (ndx != 1)
143  newoff = bp[ndx - 1];
144  else
145  newoff = hashp->BSIZE;
146  pairlen = newoff - bp[ndx + 1];
147 
148  if (ndx != (n - 1)) {
149  /* Hard Case -- need to shuffle keys */
150  register int i;
151  register char *src = bufp->page + (int)OFFSET(bp);
152  register char *dst = src + (int)pairlen;
153  memmove(dst, src, bp[ndx + 1] - OFFSET(bp));
154 
155  /* Now adjust the pointers */
156  for (i = ndx + 2; i <= n; i += 2) {
157  if (bp[i + 1] == OVFLPAGE) {
158  bp[i - 2] = bp[i];
159  bp[i - 1] = bp[i + 1];
160  } else {
161  bp[i - 2] = bp[i] + pairlen;
162  bp[i - 1] = bp[i + 1] + pairlen;
163  }
164  }
165  }
166  /* Finally adjust the page data */
167  bp[n] = OFFSET(bp) + pairlen;
168  bp[n - 1] = bp[n + 1] + pairlen + 2 * sizeof(u_int16_t);
169  bp[0] = n - 2;
170  hashp->NKEYS--;
171 
172  bufp->flags |= BUF_MOD;
173  return (0);
174 }
175 /*
176  * Returns:
177  * 0 ==> OK
178  * -1 ==> Error
179  */
180 extern int
181 __split_page(hashp, obucket, nbucket)
182  HTAB *hashp;
183  u_int32_t obucket, nbucket;
184 {
185  register BUFHEAD *new_bufp, *old_bufp;
186  register u_int16_t *ino;
187  register char *np;
188  DBT key, val;
189  int n, ndx, retval;
190  u_int16_t copyto, diff, off, moved;
191  char *op;
192 
193  copyto = (u_int16_t)hashp->BSIZE;
194  off = (u_int16_t)hashp->BSIZE;
195  old_bufp = __get_buf(hashp, obucket, NULL, 0);
196  if (old_bufp == NULL)
197  return (-1);
198  new_bufp = __get_buf(hashp, nbucket, NULL, 0);
199  if (new_bufp == NULL)
200  return (-1);
201 
202  old_bufp->flags |= (BUF_MOD | BUF_PIN);
203  new_bufp->flags |= (BUF_MOD | BUF_PIN);
204 
205  ino = (u_int16_t *)(op = old_bufp->page);
206  np = new_bufp->page;
207 
208  moved = 0;
209 
210  for (n = 1, ndx = 1; n < ino[0]; n += 2) {
211  if (ino[n + 1] < REAL_KEY) {
212  retval = ugly_split(hashp, obucket, old_bufp, new_bufp,
213  (int)copyto, (int)moved);
214  old_bufp->flags &= ~BUF_PIN;
215  new_bufp->flags &= ~BUF_PIN;
216  return (retval);
217 
218  }
219  key.data = (u_char *)op + ino[n];
220  key.size = off - ino[n];
221 
222  if (__call_hash(hashp, key.data, key.size) == obucket) {
223  /* Don't switch page */
224  diff = copyto - off;
225  if (diff) {
226  copyto = ino[n + 1] + diff;
227  memmove(op + copyto, op + ino[n + 1],
228  off - ino[n + 1]);
229  ino[ndx] = copyto + ino[n] - ino[n + 1];
230  ino[ndx + 1] = copyto;
231  } else
232  copyto = ino[n + 1];
233  ndx += 2;
234  } else {
235  /* Switch page */
236  val.data = (u_char *)op + ino[n + 1];
237  val.size = ino[n] - ino[n + 1];
238  putpair(np, &key, &val);
239  moved += 2;
240  }
241 
242  off = ino[n + 1];
243  }
244 
245  /* Now clean up the page */
246  ino[0] -= moved;
247  FREESPACE(ino) = copyto - sizeof(u_int16_t) * (ino[0] + 3);
248  OFFSET(ino) = copyto;
249 
250 #ifdef DEBUG3
251  (void)fprintf(stderr, "split %d/%d\n",
252  ((u_int16_t *)np)[0] / 2,
253  ((u_int16_t *)op)[0] / 2);
254 #endif
255  /* unpin both pages */
256  old_bufp->flags &= ~BUF_PIN;
257  new_bufp->flags &= ~BUF_PIN;
258  return (0);
259 }
260 
261 /*
262  * Called when we encounter an overflow or big key/data page during split
263  * handling. This is special cased since we have to begin checking whether
264  * the key/data pairs fit on their respective pages and because we may need
265  * overflow pages for both the old and new pages.
266  *
267  * The first page might be a page with regular key/data pairs in which case
268  * we have a regular overflow condition and just need to go on to the next
269  * page or it might be a big key/data pair in which case we need to fix the
270  * big key/data pair.
271  *
272  * Returns:
273  * 0 ==> success
274  * -1 ==> failure
275  */
276 static int
277 ugly_split(hashp, obucket, old_bufp, new_bufp, copyto, moved)
278  HTAB *hashp;
279  u_int32_t obucket; /* Same as __split_page. */
280  BUFHEAD *old_bufp, *new_bufp;
281  int copyto; /* First byte on page which contains key/data values. */
282  int moved; /* Number of pairs moved to new page. */
283 {
284  register BUFHEAD *bufp; /* Buffer header for ino */
285  register u_int16_t *ino; /* Page keys come off of */
286  register u_int16_t *np; /* New page */
287  register u_int16_t *op; /* Page keys go on to if they aren't moving */
288 
289  BUFHEAD *last_bfp; /* Last buf header OVFL needing to be freed */
290  DBT key, val;
291  SPLIT_RETURN ret;
292  u_int16_t n, off, ov_addr, scopyto;
293  char *cino; /* Character value of ino */
294 
295  bufp = old_bufp;
296  ino = (u_int16_t *)old_bufp->page;
297  np = (u_int16_t *)new_bufp->page;
298  op = (u_int16_t *)old_bufp->page;
299  last_bfp = NULL;
300  scopyto = (u_int16_t)copyto; /* ANSI */
301 
302  n = ino[0] - 1;
303  while (n < ino[0]) {
304  if (ino[2] < REAL_KEY && ino[2] != OVFLPAGE) {
305  if (__big_split(hashp, old_bufp,
306  new_bufp, bufp, bufp->addr, obucket, &ret))
307  return (-1);
308  old_bufp = ret.oldp;
309  if (!old_bufp)
310  return (-1);
311  op = (u_int16_t *)old_bufp->page;
312  new_bufp = ret.newp;
313  if (!new_bufp)
314  return (-1);
315  np = (u_int16_t *)new_bufp->page;
316  bufp = ret.nextp;
317  if (!bufp)
318  return (0);
319  cino = (char *)bufp->page;
320  ino = (u_int16_t *)cino;
321  last_bfp = ret.nextp;
322  } else if (ino[n + 1] == OVFLPAGE) {
323  ov_addr = ino[n];
324  /*
325  * Fix up the old page -- the extra 2 are the fields
326  * which contained the overflow information.
327  */
328  ino[0] -= (moved + 2);
329  FREESPACE(ino) =
330  scopyto - sizeof(u_int16_t) * (ino[0] + 3);
331  OFFSET(ino) = scopyto;
332 
333  bufp = __get_buf(hashp, ov_addr, bufp, 0);
334  if (!bufp)
335  return (-1);
336 
337  ino = (u_int16_t *)bufp->page;
338  n = 1;
339  scopyto = hashp->BSIZE;
340  moved = 0;
341 
342  if (last_bfp)
343  __free_ovflpage(hashp, last_bfp);
344  last_bfp = bufp;
345  }
346  /* Move regular sized pairs of there are any */
347  off = hashp->BSIZE;
348  for (n = 1; (n < ino[0]) && (ino[n + 1] >= REAL_KEY); n += 2) {
349  cino = (char *)ino;
350  key.data = (u_char *)cino + ino[n];
351  key.size = off - ino[n];
352  val.data = (u_char *)cino + ino[n + 1];
353  val.size = ino[n] - ino[n + 1];
354  off = ino[n + 1];
355 
356  if (__call_hash(hashp, key.data, key.size) == obucket) {
357  /* Keep on old page */
358  if (PAIRFITS(op, (&key), (&val)))
359  putpair((char *)op, &key, &val);
360  else {
361  old_bufp =
362  __add_ovflpage(hashp, old_bufp);
363  if (!old_bufp)
364  return (-1);
365  op = (u_int16_t *)old_bufp->page;
366  putpair((char *)op, &key, &val);
367  }
368  old_bufp->flags |= BUF_MOD;
369  } else {
370  /* Move to new page */
371  if (PAIRFITS(np, (&key), (&val)))
372  putpair((char *)np, &key, &val);
373  else {
374  new_bufp =
375  __add_ovflpage(hashp, new_bufp);
376  if (!new_bufp)
377  return (-1);
378  np = (u_int16_t *)new_bufp->page;
379  putpair((char *)np, &key, &val);
380  }
381  new_bufp->flags |= BUF_MOD;
382  }
383  }
384  }
385  if (last_bfp)
386  __free_ovflpage(hashp, last_bfp);
387  return (0);
388 }
389 
390 /*
391  * Add the given pair to the page
392  *
393  * Returns:
394  * 0 ==> OK
395  * 1 ==> failure
396  */
397 extern int
398 __addel(hashp, bufp, key, val)
399  HTAB *hashp;
400  BUFHEAD *bufp;
401  const DBT *key, *val;
402 {
403  register u_int16_t *bp, *sop;
404  int do_expand;
405 
406  bp = (u_int16_t *)bufp->page;
407  do_expand = 0;
408  while (bp[0] && (bp[2] < REAL_KEY || bp[bp[0]] < REAL_KEY))
409  /* Exception case */
410  if (bp[2] == FULL_KEY_DATA && bp[0] == 2)
411  /* This is the last page of a big key/data pair
412  and we need to add another page */
413  break;
414  else if (bp[2] < REAL_KEY && bp[bp[0]] != OVFLPAGE) {
415  bufp = __get_buf(hashp, bp[bp[0] - 1], bufp, 0);
416  if (!bufp)
417  return (-1);
418  bp = (u_int16_t *)bufp->page;
419  } else
420  /* Try to squeeze key on this page */
421  if (FREESPACE(bp) > PAIRSIZE(key, val)) {
422  squeeze_key(bp, key, val);
423  return (0);
424  } else {
425  bufp = __get_buf(hashp, bp[bp[0] - 1], bufp, 0);
426  if (!bufp)
427  return (-1);
428  bp = (u_int16_t *)bufp->page;
429  }
430 
431  if (PAIRFITS(bp, key, val))
432  putpair(bufp->page, key, val);
433  else {
434  do_expand = 1;
435  bufp = __add_ovflpage(hashp, bufp);
436  if (!bufp)
437  return (-1);
438  sop = (u_int16_t *)bufp->page;
439 
440  if (PAIRFITS(sop, key, val))
441  putpair((char *)sop, key, val);
442  else
443  if (__big_insert(hashp, bufp, key, val))
444  return (-1);
445  }
446  bufp->flags |= BUF_MOD;
447  /*
448  * If the average number of keys per bucket exceeds the fill factor,
449  * expand the table.
450  */
451  hashp->NKEYS++;
452  if (do_expand ||
453  (hashp->NKEYS / (hashp->MAX_BUCKET + 1) > hashp->FFACTOR))
454  return (__expand_table(hashp));
455  return (0);
456 }
457 
458 /*
459  *
460  * Returns:
461  * pointer on success
462  * NULL on error
463  */
464 extern BUFHEAD *
465 __add_ovflpage(hashp, bufp)
466  HTAB *hashp;
467  BUFHEAD *bufp;
468 {
469  register u_int16_t *sp;
470  u_int16_t ndx, ovfl_num;
471 #ifdef DEBUG1
472  int tmp1, tmp2;
473 #endif
474  sp = (u_int16_t *)bufp->page;
475 
476  /* Check if we are dynamically determining the fill factor */
477  if (hashp->FFACTOR == DEF_FFACTOR) {
478  hashp->FFACTOR = sp[0] >> 1;
479  if (hashp->FFACTOR < MIN_FFACTOR)
480  hashp->FFACTOR = MIN_FFACTOR;
481  }
482  bufp->flags |= BUF_MOD;
483  ovfl_num = overflow_page(hashp);
484 #ifdef DEBUG1
485  tmp1 = bufp->addr;
486  tmp2 = bufp->ovfl ? bufp->ovfl->addr : 0;
487 #endif
488  if (!ovfl_num || !(bufp->ovfl = __get_buf(hashp, ovfl_num, bufp, 1)))
489  return (NULL);
490  bufp->ovfl->flags |= BUF_MOD;
491 #ifdef DEBUG1
492  (void)fprintf(stderr, "ADDOVFLPAGE: %d->ovfl was %d is now %d\n",
493  tmp1, tmp2, bufp->ovfl->addr);
494 #endif
495  ndx = sp[0];
496  /*
497  * Since a pair is allocated on a page only if there's room to add
498  * an overflow page, we know that the OVFL information will fit on
499  * the page.
500  */
501  sp[ndx + 4] = OFFSET(sp);
502  sp[ndx + 3] = FREESPACE(sp) - OVFLSIZE;
503  sp[ndx + 1] = ovfl_num;
504  sp[ndx + 2] = OVFLPAGE;
505  sp[0] = ndx + 2;
506 #ifdef HASH_STATISTICS
507  hash_overflows++;
508 #endif
509  return (bufp->ovfl);
510 }
511 
512 /*
513  * Returns:
514  * 0 indicates SUCCESS
515  * -1 indicates FAILURE
516  */
517 extern int
518 __get_page(hashp, p, bucket, is_bucket, is_disk, is_bitmap)
519  HTAB *hashp;
520  char *p;
521  u_int32_t bucket;
522  int is_bucket, is_disk, is_bitmap;
523 {
524  register int fd, page, size;
525  int rsize;
526  u_int16_t *bp;
527 
528  fd = hashp->fp;
529  size = hashp->BSIZE;
530 
531  if ((fd == -1) || !is_disk) {
532  PAGE_INIT(p);
533  return (0);
534  }
535  if (is_bucket)
536  page = BUCKET_TO_PAGE(bucket);
537  else
538  page = OADDR_TO_PAGE(bucket);
539  if ((lseek(fd, (off_t)page << hashp->BSHIFT, SEEK_SET) == -1) ||
540  ((rsize = read(fd, p, size)) == -1))
541  return (-1);
542  bp = (u_int16_t *)p;
543  if (!rsize)
544  bp[0] = 0; /* We hit the EOF, so initialize a new page */
545  else
546  if (rsize != size) {
547  errno = EFTYPE;
548  return (-1);
549  }
550  if (!is_bitmap && !bp[0]) {
551  PAGE_INIT(p);
552  } else
553  if (hashp->LORDER != BYTE_ORDER) {
554  register int i, max;
555 
556  if (is_bitmap) {
557  max = hashp->BSIZE >> 2; /* divide by 4 */
558  for (i = 0; i < max; i++)
559  M_32_SWAP(((int *)p)[i]);
560  } else {
561  M_16_SWAP(bp[0]);
562  max = bp[0] + 2;
563  for (i = 1; i <= max; i++)
564  M_16_SWAP(bp[i]);
565  }
566  }
567  return (0);
568 }
569 
570 /*
571  * Write page p to disk
572  *
573  * Returns:
574  * 0 ==> OK
575  * -1 ==>failure
576  */
577 extern int
578 __put_page(hashp, p, bucket, is_bucket, is_bitmap)
579  HTAB *hashp;
580  char *p;
581  u_int32_t bucket;
582  int is_bucket, is_bitmap;
583 {
584  register int fd, page, size;
585  int wsize;
586 
587  size = hashp->BSIZE;
588  if ((hashp->fp == -1) && open_temp(hashp))
589  return (-1);
590  fd = hashp->fp;
591 
592  if (hashp->LORDER != BYTE_ORDER) {
593  register int i;
594  register int max;
595 
596  if (is_bitmap) {
597  max = hashp->BSIZE >> 2; /* divide by 4 */
598  for (i = 0; i < max; i++)
599  M_32_SWAP(((int *)p)[i]);
600  } else {
601  max = ((u_int16_t *)p)[0] + 2;
602  for (i = 0; i <= max; i++)
603  M_16_SWAP(((u_int16_t *)p)[i]);
604  }
605  }
606  if (is_bucket)
607  page = BUCKET_TO_PAGE(bucket);
608  else
609  page = OADDR_TO_PAGE(bucket);
610  if ((lseek(fd, (off_t)page << hashp->BSHIFT, SEEK_SET) == -1) ||
611  ((wsize = write(fd, p, size)) == -1))
612  /* Errno is set */
613  return (-1);
614  if (wsize != size) {
615  errno = EFTYPE;
616  return (-1);
617  }
618  return (0);
619 }
620 
621 #define BYTE_MASK ((1 << INT_BYTE_SHIFT) -1)
622 /*
623  * Initialize a new bitmap page. Bitmap pages are left in memory
624  * once they are read in.
625  */
626 extern int
627 __ibitmap(hashp, pnum, nbits, ndx)
628  HTAB *hashp;
629  int pnum, nbits, ndx;
630 {
631  u_int32_t *ip;
632  int clearbytes, clearints;
633 
634  if ((ip = (u_int32_t *)malloc(hashp->BSIZE)) == NULL)
635  return (1);
636  hashp->nmaps++;
637  clearints = ((nbits - 1) >> INT_BYTE_SHIFT) + 1;
638  clearbytes = clearints << INT_TO_BYTE;
639  (void)memset((char *)ip, 0, clearbytes);
640  (void)memset(((char *)ip) + clearbytes, 0xFF,
641  hashp->BSIZE - clearbytes);
642  ip[clearints - 1] = ALL_SET << (nbits & BYTE_MASK);
643  SETBIT(ip, 0);
644  hashp->BITMAPS[ndx] = (u_int16_t)pnum;
645  hashp->mapp[ndx] = ip;
646  return (0);
647 }
648 
649 static u_int32_t
651  u_int32_t map;
652 {
653  register u_int32_t i, mask;
654 
655  mask = 0x1;
656  for (i = 0; i < BITS_PER_MAP; i++) {
657  if (!(mask & map))
658  return (i);
659  mask = mask << 1;
660  }
661  return (i);
662 }
663 
664 static u_int16_t
666  HTAB *hashp;
667 {
668  register u_int32_t *freep = 0;
669  register int max_free, offset, splitnum;
670  u_int16_t addr;
671  int bit, first_page, free_bit, free_page, i, in_use_bits, j;
672 #ifdef DEBUG2
673  int tmp1, tmp2;
674 #endif
675  splitnum = hashp->OVFL_POINT;
676  max_free = hashp->SPARES[splitnum];
677 
678  free_page = (max_free - 1) >> (hashp->BSHIFT + BYTE_SHIFT);
679  free_bit = (max_free - 1) & ((hashp->BSIZE << BYTE_SHIFT) - 1);
680 
681  /* Look through all the free maps to find the first free block */
682  first_page = hashp->LAST_FREED >>(hashp->BSHIFT + BYTE_SHIFT);
683  for ( i = first_page; i <= free_page; i++ ) {
684  if (!(freep = (u_int32_t *)hashp->mapp[i]) &&
685  !(freep = fetch_bitmap(hashp, i)))
686  return (0);
687  if (i == free_page)
688  in_use_bits = free_bit;
689  else
690  in_use_bits = (hashp->BSIZE << BYTE_SHIFT) - 1;
691 
692  if (i == first_page) {
693  bit = hashp->LAST_FREED &
694  ((hashp->BSIZE << BYTE_SHIFT) - 1);
695  j = bit / BITS_PER_MAP;
696  bit = bit & ~(BITS_PER_MAP - 1);
697  } else {
698  bit = 0;
699  j = 0;
700  }
701  for (; bit <= in_use_bits; j++, bit += BITS_PER_MAP)
702  if (freep[j] != ALL_SET)
703  goto found;
704  }
705 
706  /* No Free Page Found */
707  hashp->LAST_FREED = hashp->SPARES[splitnum];
708  hashp->SPARES[splitnum]++;
709  offset = hashp->SPARES[splitnum] -
710  (splitnum ? hashp->SPARES[splitnum - 1] : 0);
711 
712 #define OVMSG "HASH: Out of overflow pages. Increase page size\n"
713  if (offset > SPLITMASK) {
714  if (++splitnum >= NCACHED) {
715  if (write(STDERR_FILENO, OVMSG, sizeof(OVMSG) - 1) < 0) {
716  }
717  return (0);
718  }
719  hashp->OVFL_POINT = splitnum;
720  hashp->SPARES[splitnum] = hashp->SPARES[splitnum-1];
721  hashp->SPARES[splitnum-1]--;
722  offset = 1;
723  }
724 
725  /* Check if we need to allocate a new bitmap page */
726  if (free_bit == (hashp->BSIZE << BYTE_SHIFT) - 1) {
727  free_page++;
728  if (free_page >= NCACHED) {
729  if (write(STDERR_FILENO, OVMSG, sizeof(OVMSG) - 1) < 0) {
730  }
731  return (0);
732  }
733  /*
734  * This is tricky. The 1 indicates that you want the new page
735  * allocated with 1 clear bit. Actually, you are going to
736  * allocate 2 pages from this map. The first is going to be
737  * the map page, the second is the overflow page we were
738  * looking for. The init_bitmap routine automatically, sets
739  * the first bit of itself to indicate that the bitmap itself
740  * is in use. We would explicitly set the second bit, but
741  * don't have to if we tell init_bitmap not to leave it clear
742  * in the first place.
743  */
744  if (__ibitmap(hashp,
745  (int)OADDR_OF(splitnum, offset), 1, free_page))
746  return (0);
747  hashp->SPARES[splitnum]++;
748 #ifdef DEBUG2
749  free_bit = 2;
750 #endif
751  offset++;
752  if (offset > SPLITMASK) {
753  if (++splitnum >= NCACHED) {
754  if (write(STDERR_FILENO, OVMSG, sizeof(OVMSG) - 1) < 0) {
755  }
756  return (0);
757  }
758  hashp->OVFL_POINT = splitnum;
759  hashp->SPARES[splitnum] = hashp->SPARES[splitnum-1];
760  hashp->SPARES[splitnum-1]--;
761  offset = 0;
762  }
763  } else {
764  /*
765  * Free_bit addresses the last used bit. Bump it to address
766  * the first available bit.
767  */
768  free_bit++;
769  SETBIT(freep, free_bit);
770  }
771 
772  /* Calculate address of the new overflow page */
773  addr = OADDR_OF(splitnum, offset);
774 #ifdef DEBUG2
775  (void)fprintf(stderr, "OVERFLOW_PAGE: ADDR: %d BIT: %d PAGE %d\n",
776  addr, free_bit, free_page);
777 #endif
778  return (addr);
779 
780 found:
781  bit = bit + first_free(freep[j]);
782  SETBIT(freep, bit);
783 #ifdef DEBUG2
784  tmp1 = bit;
785  tmp2 = i;
786 #endif
787  /*
788  * Bits are addressed starting with 0, but overflow pages are addressed
789  * beginning at 1. Bit is a bit addressnumber, so we need to increment
790  * it to convert it to a page number.
791  */
792  bit = 1 + bit + (i * (hashp->BSIZE << BYTE_SHIFT));
793  if (bit >= hashp->LAST_FREED)
794  hashp->LAST_FREED = bit - 1;
795 
796  /* Calculate the split number for this page */
797  for (i = 0; (i < splitnum) && (bit > hashp->SPARES[i]); i++);
798  offset = (i ? bit - hashp->SPARES[i - 1] : bit);
799  if (offset >= SPLITMASK)
800  return (0); /* Out of overflow pages */
801  addr = OADDR_OF(i, offset);
802 #ifdef DEBUG2
803  (void)fprintf(stderr, "OVERFLOW_PAGE: ADDR: %d BIT: %d PAGE %d\n",
804  addr, tmp1, tmp2);
805 #endif
806 
807  /* Allocate and return the overflow page */
808  return (addr);
809 }
810 
811 /*
812  * Mark this overflow page as free.
813  */
814 extern void
815 __free_ovflpage(hashp, obufp)
816  HTAB *hashp;
817  BUFHEAD *obufp;
818 {
819  register u_int16_t addr;
820  u_int32_t *freep;
821  int bit_address, free_page, free_bit;
822  u_int16_t ndx;
823 
824  addr = obufp->addr;
825 #ifdef DEBUG1
826  (void)fprintf(stderr, "Freeing %d\n", addr);
827 #endif
828  ndx = (((u_int16_t)addr) >> SPLITSHIFT);
829  bit_address =
830  (ndx ? hashp->SPARES[ndx - 1] : 0) + (addr & SPLITMASK) - 1;
831  if (bit_address < hashp->LAST_FREED)
832  hashp->LAST_FREED = bit_address;
833  free_page = (bit_address >> (hashp->BSHIFT + BYTE_SHIFT));
834  free_bit = bit_address & ((hashp->BSIZE << BYTE_SHIFT) - 1);
835 
836  if (!(freep = hashp->mapp[free_page]))
837  freep = fetch_bitmap(hashp, free_page);
838 #ifdef DEBUG
839  /*
840  * This had better never happen. It means we tried to read a bitmap
841  * that has already had overflow pages allocated off it, and we
842  * failed to read it from the file.
843  */
844  if (!freep)
845  assert(0);
846 #endif
847  CLRBIT(freep, free_bit);
848 #ifdef DEBUG2
849  (void)fprintf(stderr, "FREE_OVFLPAGE: ADDR: %d BIT: %d PAGE %d\n",
850  obufp->addr, free_bit, free_page);
851 #endif
852  __reclaim_buf(hashp, obufp);
853 }
854 
855 /*
856  * Returns:
857  * 0 success
858  * -1 failure
859  */
860 static int
861 open_temp(hashp)
862  HTAB *hashp;
863 {
864  sigset_t set, oset;
865  static char namestr[] = "_hashXXXXXX";
866 
867  /* Block signals; make sure file goes away at process exit. */
868  (void)sigfillset(&set);
869  (void)sigprocmask(SIG_BLOCK, &set, &oset);
870  if ((hashp->fp = mkstemp(namestr)) != -1) {
871  (void)unlink(namestr);
872  (void)fcntl(hashp->fp, F_SETFD, 1);
873  }
874  (void)sigprocmask(SIG_SETMASK, &oset, (sigset_t *)NULL);
875  return (hashp->fp != -1 ? 0 : -1);
876 }
877 
878 /*
879  * We have to know that the key will fit, but the last entry on the page is
880  * an overflow pair, so we need to shift things.
881  */
882 static void
883 squeeze_key(sp, key, val)
884  u_int16_t *sp;
885  const DBT *key, *val;
886 {
887  register char *p;
888  u_int16_t free_space, n, off, pageno;
889 
890  p = (char *)sp;
891  n = sp[0];
892  free_space = FREESPACE(sp);
893  off = OFFSET(sp);
894 
895  pageno = sp[n - 1];
896  off -= key->size;
897  sp[n - 1] = off;
898  memmove(p + off, key->data, key->size);
899  off -= val->size;
900  sp[n] = off;
901  memmove(p + off, val->data, val->size);
902  sp[0] = n + 2;
903  sp[n + 1] = pageno;
904  sp[n + 2] = OVFLPAGE;
905  FREESPACE(sp) = free_space - PAIRSIZE(key, val);
906  OFFSET(sp) = off;
907 }
908 
909 static u_int32_t *
910 fetch_bitmap(hashp, ndx)
911  HTAB *hashp;
912  int ndx;
913 {
914  if (ndx >= hashp->nmaps)
915  return (NULL);
916  if ((hashp->mapp[ndx] = (u_int32_t *)malloc(hashp->BSIZE)) == NULL)
917  return (NULL);
918  if (__get_page(hashp,
919  (char *)hashp->mapp[ndx], hashp->BITMAPS[ndx], 0, 1, 1)) {
920  free(hashp->mapp[ndx]);
921  return (NULL);
922  }
923  return (hashp->mapp[ndx]);
924 }
925 
926 #ifdef DEBUG4
927 int
928 print_chain(addr)
929  int addr;
930 {
931  BUFHEAD *bufp;
932  short *bp, oaddr;
933 
934  (void)fprintf(stderr, "%d ", addr);
935  bufp = __get_buf(hashp, addr, NULL, 0);
936  bp = (short *)bufp->page;
937  while (bp[0] && ((bp[bp[0]] == OVFLPAGE) ||
938  ((bp[0] > 2) && bp[2] < REAL_KEY))) {
939  oaddr = bp[bp[0] - 1];
940  (void)fprintf(stderr, "%d ", (int)oaddr);
941  bufp = __get_buf(hashp, (int)oaddr, bufp, 0);
942  bp = (short *)bufp->page;
943  }
944  (void)fprintf(stderr, "\n");
945 }
946 #endif
#define BUCKET_TO_PAGE(B)
Definition: hash.h:172
void * data
Definition: db.h:86
#define FREESPACE(P)
Definition: page.h:80
BUFHEAD * __add_ovflpage(HTAB *hashp, BUFHEAD *bufp)
Definition: hash_page.c:465
#define BYTE_SHIFT
Definition: hash.h:138
u_int32_t addr
Definition: hash.h:51
size_t size
Definition: db.h:87
#define SETBIT(A, N)
Definition: hash.h:154
static u_int16_t overflow_page(HTAB *hashp)
Definition: hash_page.c:665
Definition: ast_expr2.c:325
BUFHEAD * nextp
Definition: page.h:90
#define SPLITMASK
Definition: hash.h:167
int __expand_table(HTAB *hashp)
Definition: hash.c:815
int __addel(HTAB *hashp, BUFHEAD *bufp, const DBT *key, const DBT *val)
Definition: hash_page.c:398
static int * map
Definition: misdn_config.c:438
int nmaps
Definition: hash.h:114
BUFHEAD * ovfl
Definition: hash.h:50
#define OADDR_TO_PAGE(B)
Definition: hash.h:174
u_int32_t * mapp[NCACHED]
Definition: hash.h:113
#define ALL_SET
Definition: hash.h:141
#define REAL_KEY
Definition: hash.h:271
if(!yyg->yy_init)
Definition: ast_expr2f.c:868
Definition: db.h:85
#define INT_BYTE_SHIFT
Definition: hash.h:140
#define BYTE_MASK
Definition: hash_page.c:621
#define MIN_FFACTOR
Definition: hash.h:134
#define NCACHED
Definition: hash.h:85
#define NULL
Definition: resample.c:96
static u_int32_t *fetch_bitmap __P((HTAB *, int))
int fp
Definition: hash.h:100
Definition: hash.h:92
static u_int32_t first_free(u_int32_t map)
Definition: hash_page.c:650
#define PAIRSIZE(K, D)
Definition: page.h:76
char * page
Definition: hash.h:52
static void squeeze_key(u_int16_t *sp, const DBT *key, const DBT *val)
Definition: hash_page.c:883
#define OVMSG
char * malloc()
int __big_insert(HTAB *hashp, BUFHEAD *bufp, const DBT *key, const DBT *val)
Definition: hash_bigkey.c:88
void free()
#define PAIRFITS(P, K, D)
Definition: page.h:82
#define OVFLSIZE
Definition: page.h:79
#define BUF_MOD
Definition: hash.h:54
while(1)
Definition: ast_expr2f.c:894
#define SPLITSHIFT
Definition: hash.h:166
u_int32_t __call_hash(HTAB *hashp, char *k, int len)
Definition: hash.c:886
int __delpair(HTAB *hashp, BUFHEAD *bufp, int ndx)
Definition: hash_page.c:128
int __put_page(HTAB *hashp, char *p, u_int32_t bucket, int is_bucket, int is_bitmap)
Definition: hash_page.c:578
Definition: hash.h:47
#define BITS_PER_MAP
Definition: hash.h:150
#define LAST_FREED
Definition: hash.h:281
#define CLRBIT(A, N)
Definition: hash.h:153
#define OFFSET(P)
Definition: page.h:81
#define BYTE_ORDER
static void putpair(char *p, const DBT *key, const DBT *val)
Definition: hash_page.c:96
int errno
int __big_split(HTAB *hashp, BUFHEAD *op, BUFHEAD *np, BUFHEAD *big_keyp, int addr, u_int32_t obucket, SPLIT_RETURN *ret)
Definition: hash_bigkey.c:570
static int ugly_split(HTAB *hashp, u_int32_t obucket, BUFHEAD *old_bufp, BUFHEAD *new_bufp, int copyto, int moved)
Definition: hash_page.c:277
void __reclaim_buf(HTAB *hashp, BUFHEAD *bp)
Definition: hash_buf.c:346
unsigned short u_int16_t
#define EFTYPE
BUFHEAD * newp
Definition: page.h:88
BUFHEAD * oldp
Definition: page.h:89
char flags
Definition: hash.h:53
unsigned int u_int32_t
#define BUF_PIN
Definition: hash.h:57
#define OVFLPAGE
Definition: hash.h:267
#define FULL_KEY_DATA
Definition: hash.h:270
int __get_page(HTAB *hashp, char *p, u_int32_t bucket, int is_bucket, int is_disk, int is_bitmap)
Definition: hash_page.c:518
BUFHEAD * __get_buf(HTAB *hashp, u_int32_t addr, BUFHEAD *prev_bp, int newpage)
Definition: hash_buf.c:105
#define OADDR_OF(S, O)
Definition: hash.h:170
#define INT_TO_BYTE
Definition: hash.h:139
#define DEF_FFACTOR
Definition: hash.h:133
static ENTRY retval
Definition: hsearch.c:50
static u_int32_t * fetch_bitmap(HTAB *hashp, int ndx)
Definition: hash_page.c:910
#define PAGE_INIT(P)
Definition: hash_page.c:84
int __ibitmap(HTAB *hashp, int pnum, int nbits, int ndx)
Definition: hash_page.c:627
int __split_page(HTAB *hashp, u_int32_t obucket, u_int32_t nbucket)
Definition: hash_page.c:181
void __free_ovflpage(HTAB *hashp, BUFHEAD *obufp)
Definition: hash_page.c:815
int __big_delete(HTAB *hashp, BUFHEAD *bufp)
Definition: hash_bigkey.c:188
static int open_temp(HTAB *hashp)
Definition: hash_page.c:861
#define max(a, b)
Definition: f2c.h:198