1 /* $NetBSD: hash.h,v 1.17 2020/02/21 22:04:06 kamil Exp $ */ 2 3 /*- 4 * Copyright (c) 1990, 1993, 1994 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley by 8 * Margo Seltzer. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 * 34 * @(#)hash.h 8.3 (Berkeley) 5/31/94 35 */ 36 37 #if HAVE_NBTOOL_CONFIG_H 38 #include "nbtool_config.h" 39 #endif 40 41 /* Operations */ 42 typedef enum { 43 HASH_GET, HASH_PUT, HASH_PUTNEW, HASH_DELETE, HASH_FIRST, HASH_NEXT 44 } ACTION; 45 46 /* Buffer Management structures */ 47 typedef struct _bufhead BUFHEAD; 48 49 struct _bufhead { 50 BUFHEAD *prev; /* LRU links */ 51 BUFHEAD *next; /* LRU links */ 52 BUFHEAD *ovfl; /* Overflow page buffer header */ 53 uint32_t addr; /* Address of this page */ 54 char *page; /* Actual page data */ 55 char flags; 56 #define BUF_MOD 0x0001 57 #define BUF_DISK 0x0002 58 #define BUF_BUCKET 0x0004 59 #define BUF_PIN 0x0008 60 }; 61 62 #define IS_BUCKET(X) ((X) & BUF_BUCKET) 63 64 typedef BUFHEAD **SEGMENT; 65 66 /* Hash Table Information */ 67 typedef struct hashhdr { /* Disk resident portion */ 68 int32_t magic; /* Magic NO for hash tables */ 69 int32_t version; /* Version ID */ 70 uint32_t lorder; /* Byte Order */ 71 int32_t bsize; /* Bucket/Page Size */ 72 int32_t bshift; /* Bucket shift */ 73 int32_t dsize; /* Directory Size */ 74 int32_t ssize; /* Segment Size */ 75 int32_t sshift; /* Segment shift */ 76 int32_t ovfl_point; /* Where overflow pages are being 77 * allocated */ 78 int32_t last_freed; /* Last overflow page freed */ 79 int32_t max_bucket; /* ID of Maximum bucket in use */ 80 int32_t high_mask; /* Mask to modulo into entire table */ 81 int32_t low_mask; /* Mask to modulo into lower half of 82 * table */ 83 int32_t ffactor; /* Fill factor */ 84 int32_t nkeys; /* Number of keys in hash table */ 85 int32_t hdrpages; /* Size of table header */ 86 int32_t h_charkey; /* value of hash(CHARKEY) */ 87 #define NCACHED 32 /* number of bit maps and spare 88 * points */ 89 int32_t spares[NCACHED];/* spare pages for overflow */ 90 uint16_t bitmaps[NCACHED]; /* address of overflow page 91 * bitmaps */ 92 } HASHHDR; 93 94 typedef struct htab { /* Memory resident data structure */ 95 HASHHDR hdr; /* Header */ 96 int nsegs; /* Number of allocated segments */ 97 int exsegs; /* Number of extra allocated 98 * segments */ 99 uint32_t (*hash)(const void *, size_t); /* Hash function */ 100 int flags; /* Flag values */ 101 int fp; /* File pointer */ 102 char *tmp_buf; /* Temporary Buffer for BIG data */ 103 char *tmp_key; /* Temporary Buffer for BIG keys */ 104 BUFHEAD *cpage; /* Current page */ 105 int cbucket; /* Current bucket */ 106 int cndx; /* Index of next item on cpage */ 107 int err; /* Error Number -- for DBM 108 * compatibility */ 109 int new_file; /* Indicates if fd is backing store 110 * or no */ 111 int save_file; /* Indicates whether we need to flush 112 * file at 113 * exit */ 114 uint32_t *mapp[NCACHED]; /* Pointers to page maps */ 115 int nmaps; /* Initial number of bitmaps */ 116 int nbufs; /* Number of buffers left to 117 * allocate */ 118 BUFHEAD bufhead; /* Header of buffer lru list */ 119 SEGMENT *dir; /* Hash Bucket directory */ 120 } HTAB; 121 122 /* 123 * Constants 124 */ 125 #define MAX_BSIZE 65536 /* 2^16 */ 126 /* 127 * Make it fit in uint16_t; a better way would be to store size - 1, but 128 * then we'd need to bump the version. 129 */ 130 #define HASH_BSIZE(hp) ((hp)->BSIZE == MAX_BSIZE ? MAX_BSIZE - 1 : (hp)->BSIZE) 131 #define MIN_BUFFERS 6 132 #define MINHDRSIZE 512 133 #define DEF_BUFSIZE 65536 /* 64 K */ 134 #define DEF_BUCKET_SIZE 4096 135 #define DEF_BUCKET_SHIFT 12 /* log2(BUCKET) */ 136 #define DEF_SEGSIZE 256 137 #define DEF_SEGSIZE_SHIFT 8 /* log2(SEGSIZE) */ 138 #define DEF_DIRSIZE 256 139 #define DEF_FFACTOR 65536 140 #define MIN_FFACTOR 4 141 #define SPLTMAX 8 142 #define CHARKEY "%$sniglet^&" 143 #define NUMKEY 1038583 144 #define BYTE_SHIFT 3 145 #define INT_TO_BYTE 2 146 #define INT_BYTE_SHIFT 5 147 #define ALL_SET ((uint32_t)0xFFFFFFFF) 148 #define ALL_CLEAR 0 149 150 #define PTROF(X) ((BUFHEAD *)(void *)((u_long)(X)&~0x3)) 151 #define ISMOD(X) ((uint32_t)(u_long)(X)&0x1) 152 #define DOMOD(X) ((X) = (char *)(void *)((u_long)(X)|0x1)) 153 #define ISDISK(X) ((uint32_t)(u_long)(X)&0x2) 154 #define DODISK(X) ((X) = (char *)(void *)((u_long)(X)|0x2)) 155 156 #define BITS_PER_MAP 32 157 158 /* Given the address of the beginning of a big map, clear/set the nth bit */ 159 #define CLRBIT(A, N) ((A)[(N)/BITS_PER_MAP] &= ~(1U<<((N)%BITS_PER_MAP))) 160 #define SETBIT(A, N) ((A)[(N)/BITS_PER_MAP] |= (1U<<((N)%BITS_PER_MAP))) 161 #define ISSET(A, N) ((A)[(N)/BITS_PER_MAP] & (1U<<((N)%BITS_PER_MAP))) 162 163 /* Overflow management */ 164 /* 165 * Overflow page numbers are allocated per split point. At each doubling of 166 * the table, we can allocate extra pages. So, an overflow page number has 167 * the top 5 bits indicate which split point and the lower 11 bits indicate 168 * which page at that split point is indicated (pages within split points are 169 * numberered starting with 1). 170 */ 171 172 #define SPLITSHIFT 11 173 #define SPLITMASK 0x7FF 174 #define SPLITNUM(N) (((uint32_t)(N)) >> SPLITSHIFT) 175 #define OPAGENUM(N) ((N) & SPLITMASK) 176 #define OADDR_OF(S,O) ((uint32_t)((uint32_t)(S) << SPLITSHIFT) + (O)) 177 178 #define BUCKET_TO_PAGE(B) \ 179 (B) + hashp->HDRPAGES + \ 180 ((B) ? hashp->SPARES[__log2((uint32_t)((B)+1))-1] : 0) 181 #define OADDR_TO_PAGE(B) \ 182 BUCKET_TO_PAGE ( (1 << SPLITNUM((B))) -1 ) + OPAGENUM((B)); 183 184 /* 185 * page.h contains a detailed description of the page format. 186 * 187 * Normally, keys and data are accessed from offset tables in the top of 188 * each page which point to the beginning of the key and data. There are 189 * four flag values which may be stored in these offset tables which indicate 190 * the following: 191 * 192 * 193 * OVFLPAGE Rather than a key data pair, this pair contains 194 * the address of an overflow page. The format of 195 * the pair is: 196 * OVERFLOW_PAGE_NUMBER OVFLPAGE 197 * 198 * PARTIAL_KEY This must be the first key/data pair on a page 199 * and implies that page contains only a partial key. 200 * That is, the key is too big to fit on a single page 201 * so it starts on this page and continues on the next. 202 * The format of the page is: 203 * KEY_OFF PARTIAL_KEY OVFL_PAGENO OVFLPAGE 204 * 205 * KEY_OFF -- offset of the beginning of the key 206 * PARTIAL_KEY -- 1 207 * OVFL_PAGENO - page number of the next overflow page 208 * OVFLPAGE -- 0 209 * 210 * FULL_KEY This must be the first key/data pair on the page. It 211 * is used in two cases. 212 * 213 * Case 1: 214 * There is a complete key on the page but no data 215 * (because it wouldn't fit). The next page contains 216 * the data. 217 * 218 * Page format it: 219 * KEY_OFF FULL_KEY OVFL_PAGENO OVFL_PAGE 220 * 221 * KEY_OFF -- offset of the beginning of the key 222 * FULL_KEY -- 2 223 * OVFL_PAGENO - page number of the next overflow page 224 * OVFLPAGE -- 0 225 * 226 * Case 2: 227 * This page contains no key, but part of a large 228 * data field, which is continued on the next page. 229 * 230 * Page format it: 231 * DATA_OFF FULL_KEY OVFL_PAGENO OVFL_PAGE 232 * 233 * KEY_OFF -- offset of the beginning of the data on 234 * this page 235 * FULL_KEY -- 2 236 * OVFL_PAGENO - page number of the next overflow page 237 * OVFLPAGE -- 0 238 * 239 * FULL_KEY_DATA 240 * This must be the first key/data pair on the page. 241 * There are two cases: 242 * 243 * Case 1: 244 * This page contains a key and the beginning of the 245 * data field, but the data field is continued on the 246 * next page. 247 * 248 * Page format is: 249 * KEY_OFF FULL_KEY_DATA OVFL_PAGENO DATA_OFF 250 * 251 * KEY_OFF -- offset of the beginning of the key 252 * FULL_KEY_DATA -- 3 253 * OVFL_PAGENO - page number of the next overflow page 254 * DATA_OFF -- offset of the beginning of the data 255 * 256 * Case 2: 257 * This page contains the last page of a big data pair. 258 * There is no key, only the tail end of the data 259 * on this page. 260 * 261 * Page format is: 262 * DATA_OFF FULL_KEY_DATA <OVFL_PAGENO> <OVFLPAGE> 263 * 264 * DATA_OFF -- offset of the beginning of the data on 265 * this page 266 * FULL_KEY_DATA -- 3 267 * OVFL_PAGENO - page number of the next overflow page 268 * OVFLPAGE -- 0 269 * 270 * OVFL_PAGENO and OVFLPAGE are optional (they are 271 * not present if there is no next page). 272 */ 273 274 #define OVFLPAGE 0 275 #define PARTIAL_KEY 1 276 #define FULL_KEY 2 277 #define FULL_KEY_DATA 3 278 #define REAL_KEY 4 279 280 /* Short hands for accessing structure */ 281 #define BSIZE hdr.bsize 282 #define BSHIFT hdr.bshift 283 #define DSIZE hdr.dsize 284 #define SGSIZE hdr.ssize 285 #define SSHIFT hdr.sshift 286 #define LORDER hdr.lorder 287 #define OVFL_POINT hdr.ovfl_point 288 #define LAST_FREED hdr.last_freed 289 #define MAX_BUCKET hdr.max_bucket 290 #define FFACTOR hdr.ffactor 291 #define HIGH_MASK hdr.high_mask 292 #define LOW_MASK hdr.low_mask 293 #define NKEYS hdr.nkeys 294 #define HDRPAGES hdr.hdrpages 295 #define SPARES hdr.spares 296 #define BITMAPS hdr.bitmaps 297 #define VERSION hdr.version 298 #define MAGIC hdr.magic 299 #define NEXT_FREE hdr.next_free 300 #define H_CHARKEY hdr.h_charkey 301
Indexes created Sat Sep 20 22:09:52 GMT 2025