1/* $NetBSD: hash.h,v 1.14 2007/02/03 23:46:09 christos 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 */ 42typedef enum { 43 HASH_GET, HASH_PUT, HASH_PUTNEW, HASH_DELETE, HASH_FIRST, HASH_NEXT 44} ACTION; 45 46/* Buffer Management structures */ 47typedef struct _bufhead BUFHEAD; 48 49struct _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 64typedef BUFHEAD **SEGMENT; 65 66/* Hash Table Information */ 67typedef 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 94typedef 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#define MIN_BUFFERS 6 127#define MINHDRSIZE 512 128#define DEF_BUFSIZE 65536 /* 64 K */ 129#define DEF_BUCKET_SIZE 4096 130#define DEF_BUCKET_SHIFT 12 /* log2(BUCKET) */ 131#define DEF_SEGSIZE 256 132#define DEF_SEGSIZE_SHIFT 8 /* log2(SEGSIZE) */ 133#define DEF_DIRSIZE 256 134#define DEF_FFACTOR 65536 135#define MIN_FFACTOR 4 136#define SPLTMAX 8 137#define CHARKEY "%$sniglet^&" 138#define NUMKEY 1038583 139#define BYTE_SHIFT 3 140#define INT_TO_BYTE 2 141#define INT_BYTE_SHIFT 5 142#define ALL_SET ((uint32_t)0xFFFFFFFF) 143#define ALL_CLEAR 0 144 145#define PTROF(X) ((BUFHEAD *)(void *)((u_long)(X)&~0x3)) 146#define ISMOD(X) ((uint32_t)(u_long)(X)&0x1) 147#define DOMOD(X) ((X) = (char *)(void *)((u_long)(X)|0x1)) 148#define ISDISK(X) ((uint32_t)(u_long)(X)&0x2) 149#define DODISK(X) ((X) = (char *)(void *)((u_long)(X)|0x2)) 150 151#define BITS_PER_MAP 32 152 153/* Given the address of the beginning of a big map, clear/set the nth bit */ 154#define CLRBIT(A, N) ((A)[(N)/BITS_PER_MAP] &= ~(1<<((N)%BITS_PER_MAP))) 155#define SETBIT(A, N) ((A)[(N)/BITS_PER_MAP] |= (1<<((N)%BITS_PER_MAP))) 156#define ISSET(A, N) ((A)[(N)/BITS_PER_MAP] & (1<<((N)%BITS_PER_MAP))) 157 158/* Overflow management */ 159/* 160 * Overflow page numbers are allocated per split point. At each doubling of 161 * the table, we can allocate extra pages. So, an overflow page number has 162 * the top 5 bits indicate which split point and the lower 11 bits indicate 163 * which page at that split point is indicated (pages within split points are 164 * numberered starting with 1). 165 */ 166 167#define SPLITSHIFT 11 168#define SPLITMASK 0x7FF 169#define SPLITNUM(N) (((uint32_t)(N)) >> SPLITSHIFT) 170#define OPAGENUM(N) ((N) & SPLITMASK) 171#define OADDR_OF(S,O) ((uint32_t)((uint32_t)(S) << SPLITSHIFT) + (O)) 172 173#define BUCKET_TO_PAGE(B) \ 174 (B) + hashp->HDRPAGES + \ 175 ((B) ? hashp->SPARES[__log2((uint32_t)((B)+1))-1] : 0) 176#define OADDR_TO_PAGE(B) \ 177 BUCKET_TO_PAGE ( (1 << SPLITNUM((B))) -1 ) + OPAGENUM((B)); 178 179/* 180 * page.h contains a detailed description of the page format. 181 * 182 * Normally, keys and data are accessed from offset tables in the top of 183 * each page which point to the beginning of the key and data. There are 184 * four flag values which may be stored in these offset tables which indicate 185 * the following: 186 * 187 * 188 * OVFLPAGE Rather than a key data pair, this pair contains 189 * the address of an overflow page. The format of 190 * the pair is: 191 * OVERFLOW_PAGE_NUMBER OVFLPAGE 192 * 193 * PARTIAL_KEY This must be the first key/data pair on a page 194 * and implies that page contains only a partial key. 195 * That is, the key is too big to fit on a single page 196 * so it starts on this page and continues on the next. 197 * The format of the page is: 198 * KEY_OFF PARTIAL_KEY OVFL_PAGENO OVFLPAGE 199 * 200 * KEY_OFF -- offset of the beginning of the key 201 * PARTIAL_KEY -- 1 202 * OVFL_PAGENO - page number of the next overflow page 203 * OVFLPAGE -- 0 204 * 205 * FULL_KEY This must be the first key/data pair on the page. It 206 * is used in two cases. 207 * 208 * Case 1: 209 * There is a complete key on the page but no data 210 * (because it wouldn't fit). The next page contains 211 * the data. 212 * 213 * Page format it: 214 * KEY_OFF FULL_KEY OVFL_PAGENO OVFL_PAGE 215 * 216 * KEY_OFF -- offset of the beginning of the key 217 * FULL_KEY -- 2 218 * OVFL_PAGENO - page number of the next overflow page 219 * OVFLPAGE -- 0 220 * 221 * Case 2: 222 * This page contains no key, but part of a large 223 * data field, which is continued on the next page. 224 * 225 * Page format it: 226 * DATA_OFF FULL_KEY OVFL_PAGENO OVFL_PAGE 227 * 228 * KEY_OFF -- offset of the beginning of the data on 229 * this page 230 * FULL_KEY -- 2 231 * OVFL_PAGENO - page number of the next overflow page 232 * OVFLPAGE -- 0 233 * 234 * FULL_KEY_DATA 235 * This must be the first key/data pair on the page. 236 * There are two cases: 237 * 238 * Case 1: 239 * This page contains a key and the beginning of the 240 * data field, but the data field is continued on the 241 * next page. 242 * 243 * Page format is: 244 * KEY_OFF FULL_KEY_DATA OVFL_PAGENO DATA_OFF 245 * 246 * KEY_OFF -- offset of the beginning of the key 247 * FULL_KEY_DATA -- 3 248 * OVFL_PAGENO - page number of the next overflow page 249 * DATA_OFF -- offset of the beginning of the data 250 * 251 * Case 2: 252 * This page contains the last page of a big data pair. 253 * There is no key, only the tail end of the data 254 * on this page. 255 * 256 * Page format is: 257 * DATA_OFF FULL_KEY_DATA <OVFL_PAGENO> <OVFLPAGE> 258 * 259 * DATA_OFF -- offset of the beginning of the data on 260 * this page 261 * FULL_KEY_DATA -- 3 262 * OVFL_PAGENO - page number of the next overflow page 263 * OVFLPAGE -- 0 264 * 265 * OVFL_PAGENO and OVFLPAGE are optional (they are 266 * not present if there is no next page). 267 */ 268 269#define OVFLPAGE 0 270#define PARTIAL_KEY 1 271#define FULL_KEY 2 272#define FULL_KEY_DATA 3 273#define REAL_KEY 4 274 275/* Short hands for accessing structure */ 276#define BSIZE hdr.bsize 277#define BSHIFT hdr.bshift 278#define DSIZE hdr.dsize 279#define SGSIZE hdr.ssize 280#define SSHIFT hdr.sshift 281#define LORDER hdr.lorder 282#define OVFL_POINT hdr.ovfl_point 283#define LAST_FREED hdr.last_freed 284#define MAX_BUCKET hdr.max_bucket 285#define FFACTOR hdr.ffactor 286#define HIGH_MASK hdr.high_mask 287#define LOW_MASK hdr.low_mask 288#define NKEYS hdr.nkeys 289#define HDRPAGES hdr.hdrpages 290#define SPARES hdr.spares 291#define BITMAPS hdr.bitmaps 292#define VERSION hdr.version 293#define MAGIC hdr.magic 294#define NEXT_FREE hdr.next_free 295#define H_CHARKEY hdr.h_charkey 296