Asterisk - The Open Source Telephony Project  GIT-master-e8cda4b
Functions
bt_search.c File Reference
#include <sys/types.h>
#include <stdio.h>
#include "../include/db.h"
#include "btree.h"

Go to the source code of this file.

Functions

EPG__bt_search (BTREE *t, const DBT *key, int *exactp)
 
static int __bt_snext (BTREE *t, PAGE *h, const DBT *key, int *exactp)
 
static int __bt_sprev (BTREE *t, PAGE *h, const DBT *key, int *exactp)
 
static int __bt_snext __P ((BTREE *, PAGE *, const DBT *, int *))
 

Function Documentation

◆ __bt_search()

EPG* __bt_search ( BTREE t,
const DBT key,
int *  exactp 
)

Definition at line 66 of file bt_search.c.

References __bt_cmp(), __bt_snext(), __bt_sprev(), B_NODUPS, BT_CLR, _btree::bt_cur, _btree::bt_mp, BT_PUSH, F_ISSET, _page::flags, GETBINTERNAL, _epg::index, mpool_get(), mpool_put(), NEXTINDEX, _page::nextpg, NULL, P_BLEAF, P_INVALID, P_ROOT, _epg::page, _page::pgno, and _page::prevpg.

Referenced by __bt_bdelete(), __bt_first(), __bt_get(), __bt_put(), and __bt_stkacq().

70 {
71  PAGE *h;
72  indx_t base, index, lim;
73  pgno_t pg;
74  int cmp;
75 
76  BT_CLR(t);
77  for (pg = P_ROOT;;) {
78  if ((h = mpool_get(t->bt_mp, pg, 0)) == NULL)
79  return (NULL);
80 
81  /* Do a binary search on the current page. */
82  t->bt_cur.page = h;
83  for (base = 0, lim = NEXTINDEX(h); lim; lim >>= 1) {
84  t->bt_cur.index = index = base + (lim >> 1);
85  if ((cmp = __bt_cmp(t, key, &t->bt_cur)) == 0) {
86  if (h->flags & P_BLEAF) {
87  *exactp = 1;
88  return (&t->bt_cur);
89  }
90  goto next;
91  }
92  if (cmp > 0) {
93  base = index + 1;
94  --lim;
95  }
96  }
97 
98  /*
99  * If it's a leaf page, we're almost done. If no duplicates
100  * are allowed, or we have an exact match, we're done. Else,
101  * it's possible that there were matching keys on this page,
102  * which later deleted, and we're on a page with no matches
103  * while there are matches on other pages. If at the start or
104  * end of a page, check the adjacent page.
105  */
106  if (h->flags & P_BLEAF) {
107  if (!F_ISSET(t, B_NODUPS)) {
108  if (base == 0 &&
109  h->prevpg != P_INVALID &&
110  __bt_sprev(t, h, key, exactp))
111  return (&t->bt_cur);
112  if (base == NEXTINDEX(h) &&
113  h->nextpg != P_INVALID &&
114  __bt_snext(t, h, key, exactp))
115  return (&t->bt_cur);
116  }
117  *exactp = 0;
118  t->bt_cur.index = base;
119  return (&t->bt_cur);
120  }
121 
122  /*
123  * No match found. Base is the smallest index greater than
124  * key and may be zero or a last + 1 index. If it's non-zero,
125  * decrement by one, and record the internal page which should
126  * be a parent page for the key. If a split later occurs, the
127  * inserted page will be to the right of the saved page.
128  */
129  index = base ? base - 1 : base;
130 
131 next: BT_PUSH(t, h->pgno, index);
132  pg = GETBINTERNAL(h, index)->pgno;
133  mpool_put(t->bt_mp, h, 0);
134  }
135 }
Definition: btree.h:75
#define NEXTINDEX(p)
Definition: btree.h:98
pgno_t pgno
Definition: btree.h:76
#define F_ISSET(p, f)
Definition: btree.h:42
#define BT_PUSH(t, p, i)
Definition: btree.h:322
EPG bt_cur
Definition: btree.h:317
int mpool_put(MPOOL *mp, void *page, u_int flags)
Definition: mpool.c:251
static int __bt_sprev(BTREE *t, PAGE *h, const DBT *key, int *exactp)
Definition: bt_search.c:190
#define NULL
Definition: resample.c:96
u_int16_t indx_t
Definition: db.h:80
#define GETBINTERNAL(pg, indx)
Definition: btree.h:138
static int __bt_snext(BTREE *t, PAGE *h, const DBT *key, int *exactp)
Definition: bt_search.c:151
void * mpool_get(MPOOL *mp, pgno_t pgno, u_int flags)
Definition: mpool.c:165
u_int32_t flags
Definition: btree.h:87
PAGE * page
Definition: btree.h:255
MPOOL * bt_mp
Definition: btree.h:313
int __bt_cmp(BTREE *t, const DBT *k1, EPG *e)
Definition: bt_utils.c:153
#define B_NODUPS
Definition: btree.h:374
u_int32_t pgno_t
Definition: db.h:78
pgno_t nextpg
Definition: btree.h:78
indx_t index
Definition: btree.h:256
pgno_t prevpg
Definition: btree.h:77
#define P_ROOT
Definition: btree.h:65
#define P_INVALID
Definition: btree.h:63
#define BT_CLR(t)
Definition: btree.h:328
#define P_BLEAF
Definition: btree.h:81

◆ __bt_snext()

static int __bt_snext ( BTREE t,
PAGE h,
const DBT key,
int *  exactp 
)
static

Definition at line 151 of file bt_search.c.

References __bt_cmp(), _btree::bt_cur, _btree::bt_mp, _epg::index, mpool_get(), mpool_put(), _page::nextpg, NULL, and _epg::page.

Referenced by __bt_search().

156 {
157  EPG e;
158 
159  /*
160  * Get the next page. The key is either an exact
161  * match, or not as good as the one we already have.
162  */
163  if ((e.page = mpool_get(t->bt_mp, h->nextpg, 0)) == NULL)
164  return (0);
165  e.index = 0;
166  if (__bt_cmp(t, key, &e) == 0) {
167  mpool_put(t->bt_mp, h, 0);
168  t->bt_cur = e;
169  *exactp = 1;
170  return (1);
171  }
172  mpool_put(t->bt_mp, e.page, 0);
173  return (0);
174 }
EPG bt_cur
Definition: btree.h:317
int mpool_put(MPOOL *mp, void *page, u_int flags)
Definition: mpool.c:251
Definition: btree.h:254
#define NULL
Definition: resample.c:96
void * mpool_get(MPOOL *mp, pgno_t pgno, u_int flags)
Definition: mpool.c:165
PAGE * page
Definition: btree.h:255
MPOOL * bt_mp
Definition: btree.h:313
int __bt_cmp(BTREE *t, const DBT *k1, EPG *e)
Definition: bt_utils.c:153
pgno_t nextpg
Definition: btree.h:78
indx_t index
Definition: btree.h:256

◆ __bt_sprev()

static int __bt_sprev ( BTREE t,
PAGE h,
const DBT key,
int *  exactp 
)
static

Definition at line 190 of file bt_search.c.

References __bt_cmp(), _btree::bt_cur, _btree::bt_mp, _epg::index, mpool_get(), mpool_put(), NEXTINDEX, NULL, _epg::page, and _page::prevpg.

Referenced by __bt_search().

195 {
196  EPG e;
197 
198  /*
199  * Get the previous page. The key is either an exact
200  * match, or not as good as the one we already have.
201  */
202  if ((e.page = mpool_get(t->bt_mp, h->prevpg, 0)) == NULL)
203  return (0);
204  e.index = NEXTINDEX(e.page) - 1;
205  if (__bt_cmp(t, key, &e) == 0) {
206  mpool_put(t->bt_mp, h, 0);
207  t->bt_cur = e;
208  *exactp = 1;
209  return (1);
210  }
211  mpool_put(t->bt_mp, e.page, 0);
212  return (0);
213 }
#define NEXTINDEX(p)
Definition: btree.h:98
EPG bt_cur
Definition: btree.h:317
int mpool_put(MPOOL *mp, void *page, u_int flags)
Definition: mpool.c:251
Definition: btree.h:254
#define NULL
Definition: resample.c:96
void * mpool_get(MPOOL *mp, pgno_t pgno, u_int flags)
Definition: mpool.c:165
PAGE * page
Definition: btree.h:255
MPOOL * bt_mp
Definition: btree.h:313
int __bt_cmp(BTREE *t, const DBT *k1, EPG *e)
Definition: bt_utils.c:153
indx_t index
Definition: btree.h:256
pgno_t prevpg
Definition: btree.h:77

◆ __P()

static int __bt_sprev __P ( (BTREE *, PAGE *, const DBT *, int *)  )
static