Asterisk - The Open Source Telephony Project GIT-master-7921072
hash.h
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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 * @(#)hash.h 8.3 (Berkeley) 5/31/94
37 */
38
39/* Operations */
40typedef enum {
43
44/* Buffer Management structures */
45typedef struct _bufhead BUFHEAD;
46
47struct _bufhead {
48 BUFHEAD *prev; /* LRU links */
49 BUFHEAD *next; /* LRU links */
50 BUFHEAD *ovfl; /* Overflow page buffer header */
51 u_int32_t addr; /* Address of this page */
52 char *page; /* Actual page data */
53 char flags;
54#define BUF_MOD 0x0001
55#define BUF_DISK 0x0002
56#define BUF_BUCKET 0x0004
57#define BUF_PIN 0x0008
58};
59
60#define IS_BUCKET(X) ((X) & BUF_BUCKET)
61
62typedef BUFHEAD **SEGMENT;
63
64/* Hash Table Information */
65typedef struct hashhdr { /* Disk resident portion */
66 int magic; /* Magic NO for hash tables */
67 int version; /* Version ID */
68 u_int32_t lorder; /* Byte Order */
69 int bsize; /* Bucket/Page Size */
70 int bshift; /* Bucket shift */
71 int dsize; /* Directory Size */
72 int ssize; /* Segment Size */
73 int sshift; /* Segment shift */
74 int ovfl_point; /* Where overflow pages are being
75 * allocated */
76 int last_freed; /* Last overflow page freed */
77 int max_bucket; /* ID of Maximum bucket in use */
78 int high_mask; /* Mask to modulo into entire table */
79 int low_mask; /* Mask to modulo into lower half of
80 * table */
81 int ffactor; /* Fill factor */
82 int nkeys; /* Number of keys in hash table */
83 int hdrpages; /* Size of table header */
84 int h_charkey; /* value of hash(CHARKEY) */
85#define NCACHED 32 /* number of bit maps and spare
86 * points */
87 int spares[NCACHED];/* spare pages for overflow */
88 u_int16_t bitmaps[NCACHED]; /* address of overflow page
89 * bitmaps */
90} HASHHDR;
92typedef struct htab { /* Memory resident data structure */
93 HASHHDR hdr; /* Header */
94 int nsegs; /* Number of allocated segments */
95 int exsegs; /* Number of extra allocated
96 * segments */
97 u_int32_t /* Hash function */
98 (*hash)__P((const void *, size_t));
99 int flags; /* Flag values */
100 int fp; /* File pointer */
101 char *tmp_buf; /* Temporary Buffer for BIG data */
102 char *tmp_key; /* Temporary Buffer for BIG keys */
103 BUFHEAD *cpage; /* Current page */
104 int cbucket; /* Current bucket */
105 int cndx; /* Index of next item on cpage */
106 int errnum; /* Error Number -- for DBM
107 * compatibility */
108 int new_file; /* Indicates if fd is backing store
109 * or no */
110 int save_file; /* Indicates whether we need to flush
111 * file at
112 * exit */
113 u_int32_t *mapp[NCACHED]; /* Pointers to page maps */
114 int nmaps; /* Initial number of bitmaps */
115 int nbufs; /* Number of buffers left to
116 * allocate */
117 BUFHEAD bufhead; /* Header of buffer lru list */
118 SEGMENT *dir; /* Hash Bucket directory */
119} HTAB;
120
121/*
122 * Constants
123 */
124#define MAX_BSIZE 65536 /* 2^16 */
125#define MIN_BUFFERS 6
126#define MINHDRSIZE 512
127#define DEF_BUFSIZE 65536 /* 64 K */
128#define DEF_BUCKET_SIZE 4096
129#define DEF_BUCKET_SHIFT 12 /* log2(BUCKET) */
130#define DEF_SEGSIZE 256
131#define DEF_SEGSIZE_SHIFT 8 /* log2(SEGSIZE) */
132#define DEF_DIRSIZE 256
133#define DEF_FFACTOR 65536
134#define MIN_FFACTOR 4
135#define SPLTMAX 8
136#define CHARKEY "%$sniglet^&"
137#define NUMKEY 1038583
138#define BYTE_SHIFT 3
139#define INT_TO_BYTE 2
140#define INT_BYTE_SHIFT 5
141#define ALL_SET ((u_int32_t)0xFFFFFFFF)
142#define ALL_CLEAR 0
144#define PTROF(X) ((BUFHEAD *)((ptrdiff_t)(X)&~0x3))
145#define ISMOD(X) ((u_int32_t)(ptrdiff_t)(X)&0x1)
146#define DOMOD(X) ((X) = (char *)((ptrdiff_t)(X)|0x1))
147#define ISDISK(X) ((u_int32_t)(ptrdiff_t)(X)&0x2)
148#define DODISK(X) ((X) = (char *)((ptrdiff_t)(X)|0x2))
150#define BITS_PER_MAP 32
151
152/* Given the address of the beginning of a big map, clear/set the nth bit */
153#define CLRBIT(A, N) ((A)[(N)/BITS_PER_MAP] &= ~(1<<((N)%BITS_PER_MAP)))
154#define SETBIT(A, N) ((A)[(N)/BITS_PER_MAP] |= (1<<((N)%BITS_PER_MAP)))
155#define ISSET(A, N) ((A)[(N)/BITS_PER_MAP] & (1<<((N)%BITS_PER_MAP)))
156
157/* Overflow management */
158/*
159 * Overflow page numbers are allocated per split point. At each doubling of
160 * the table, we can allocate extra pages. So, an overflow page number has
161 * the top 5 bits indicate which split point and the lower 11 bits indicate
162 * which page at that split point is indicated (pages within split points are
163 * numbered starting with 1).
164 */
166#define SPLITSHIFT 11
167#define SPLITMASK 0x7FF
168#define SPLITNUM(N) (((u_int32_t)(N)) >> SPLITSHIFT)
169#define OPAGENUM(N) ((N) & SPLITMASK)
170#define OADDR_OF(S,O) ((u_int32_t)((u_int32_t)(S) << SPLITSHIFT) + (O))
172#define BUCKET_TO_PAGE(B) \
173 (B) + hashp->HDRPAGES + ((B) ? hashp->SPARES[__hash_log2((B)+1)-1] : 0)
174#define OADDR_TO_PAGE(B) \
175 BUCKET_TO_PAGE ( (1 << SPLITNUM((B))) -1 ) + OPAGENUM((B));
176
177/*
178 * page.h contains a detailed description of the page format.
179 *
180 * Normally, keys and data are accessed from offset tables in the top of
181 * each page which point to the beginning of the key and data. There are
182 * four flag values which may be stored in these offset tables which indicate
183 * the following:
184 *
185 *
186 * OVFLPAGE Rather than a key data pair, this pair contains
187 * the address of an overflow page. The format of
188 * the pair is:
189 * OVERFLOW_PAGE_NUMBER OVFLPAGE
190 *
191 * PARTIAL_KEY This must be the first key/data pair on a page
192 * and implies that page contains only a partial key.
193 * That is, the key is too big to fit on a single page
194 * so it starts on this page and continues on the next.
195 * The format of the page is:
196 * KEY_OFF PARTIAL_KEY OVFL_PAGENO OVFLPAGE
197 *
198 * KEY_OFF -- offset of the beginning of the key
199 * PARTIAL_KEY -- 1
200 * OVFL_PAGENO - page number of the next overflow page
201 * OVFLPAGE -- 0
202 *
203 * FULL_KEY This must be the first key/data pair on the page. It
204 * is used in two cases.
205 *
206 * Case 1:
207 * There is a complete key on the page but no data
208 * (because it wouldn't fit). The next page contains
209 * the data.
210 *
211 * Page format it:
212 * KEY_OFF FULL_KEY OVFL_PAGENO OVFL_PAGE
213 *
214 * KEY_OFF -- offset of the beginning of the key
215 * FULL_KEY -- 2
216 * OVFL_PAGENO - page number of the next overflow page
217 * OVFLPAGE -- 0
218 *
219 * Case 2:
220 * This page contains no key, but part of a large
221 * data field, which is continued on the next page.
222 *
223 * Page format it:
224 * DATA_OFF FULL_KEY OVFL_PAGENO OVFL_PAGE
225 *
226 * KEY_OFF -- offset of the beginning of the data on
227 * this page
228 * FULL_KEY -- 2
229 * OVFL_PAGENO - page number of the next overflow page
230 * OVFLPAGE -- 0
231 *
232 * FULL_KEY_DATA
233 * This must be the first key/data pair on the page.
234 * There are two cases:
235 *
236 * Case 1:
237 * This page contains a key and the beginning of the
238 * data field, but the data field is continued on the
239 * next page.
240 *
241 * Page format is:
242 * KEY_OFF FULL_KEY_DATA OVFL_PAGENO DATA_OFF
243 *
244 * KEY_OFF -- offset of the beginning of the key
245 * FULL_KEY_DATA -- 3
246 * OVFL_PAGENO - page number of the next overflow page
247 * DATA_OFF -- offset of the beginning of the data
248 *
249 * Case 2:
250 * This page contains the last page of a big data pair.
251 * There is no key, only the tail end of the data
252 * on this page.
253 *
254 * Page format is:
255 * DATA_OFF FULL_KEY_DATA <OVFL_PAGENO> <OVFLPAGE>
256 *
257 * DATA_OFF -- offset of the beginning of the data on
258 * this page
259 * FULL_KEY_DATA -- 3
260 * OVFL_PAGENO - page number of the next overflow page
261 * OVFLPAGE -- 0
262 *
263 * OVFL_PAGENO and OVFLPAGE are optional (they are
264 * not present if there is no next page).
265 */
267#define OVFLPAGE 0
268#define PARTIAL_KEY 1
269#define FULL_KEY 2
270#define FULL_KEY_DATA 3
271#define REAL_KEY 4
272
273/* Short hands for accessing structure */
274#define BSIZE hdr.bsize
275#define BSHIFT hdr.bshift
276#define DSIZE hdr.dsize
277#define SGSIZE hdr.ssize
278#define SSHIFT hdr.sshift
279#define LORDER hdr.lorder
280#define OVFL_POINT hdr.ovfl_point
281#define LAST_FREED hdr.last_freed
282#define MAX_BUCKET hdr.max_bucket
283#define FFACTOR hdr.ffactor
284#define HIGH_MASK hdr.high_mask
285#define LOW_MASK hdr.low_mask
286#define NKEYS hdr.nkeys
287#define HDRPAGES hdr.hdrpages
288#define SPARES hdr.spares
289#define BITMAPS hdr.bitmaps
290#define VERSION hdr.version
291#define MAGIC hdr.magic
292#define NEXT_FREE hdr.next_free
293#define H_CHARKEY hdr.h_charkey
#define NCACHED
Definition: hash.h:85
struct hashhdr HASHHDR
BUFHEAD ** SEGMENT
Definition: hash.h:62
ACTION
Definition: hash.h:40
@ HASH_DELETE
Definition: hash.h:41
@ HASH_PUT
Definition: hash.h:41
@ HASH_PUTNEW
Definition: hash.h:41
@ HASH_GET
Definition: hash.h:41
@ HASH_NEXT
Definition: hash.h:41
@ HASH_FIRST
Definition: hash.h:41
struct htab HTAB
unsigned int u_int32_t
unsigned short u_int16_t
Definition: hash.h:47
char * page
Definition: hash.h:52
BUFHEAD * ovfl
Definition: hash.h:50
char flags
Definition: hash.h:53
u_int32_t addr
Definition: hash.h:51
BUFHEAD * prev
Definition: hash.h:48
BUFHEAD * next
Definition: hash.h:49
Definition: hash.h:65
int spares[NCACHED]
Definition: hash.h:86
int bsize
Definition: hash.h:69
int high_mask
Definition: hash.h:78
int hdrpages
Definition: hash.h:83
int h_charkey
Definition: hash.h:84
int bshift
Definition: hash.h:70
int ovfl_point
Definition: hash.h:74
int magic
Definition: hash.h:66
int ffactor
Definition: hash.h:81
int nkeys
Definition: hash.h:82
u_int32_t lorder
Definition: hash.h:68
int low_mask
Definition: hash.h:79
int max_bucket
Definition: hash.h:77
int version
Definition: hash.h:67
int dsize
Definition: hash.h:71
int sshift
Definition: hash.h:73
int ssize
Definition: hash.h:72
int last_freed
Definition: hash.h:76
u_int16_t bitmaps[NCACHED]
Definition: hash.h:87
Definition: hash.h:91
BUFHEAD bufhead
Definition: hash.h:116
int cbucket
Definition: hash.h:103
char * tmp_buf
Definition: hash.h:100
int save_file
Definition: hash.h:109
char * tmp_key
Definition: hash.h:101
int new_file
Definition: hash.h:107
u_int32_t hash __P((const void *, size_t))
int fp
Definition: hash.h:99
int exsegs
Definition: hash.h:94
SEGMENT * dir
Definition: hash.h:117
u_int32_t * mapp[NCACHED]
Definition: hash.h:112
int nbufs
Definition: hash.h:114
int nsegs
Definition: hash.h:93
HASHHDR hdr
Definition: hash.h:92
int errnum
Definition: hash.h:105
int nmaps
Definition: hash.h:113
BUFHEAD * cpage
Definition: hash.h:102
int cndx
Definition: hash.h:104
int flags
Definition: hash.h:98