| t2ex/bsd_source/lib/libc/src_bsd/search/hash.h | bare source | permlink (0.01 seconds) |
1: /* $OpenBSD: hash.h,v 1.9 2004/06/21 23:13:22 marc 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: /* Operations */ 38: typedef enum { 39: HASH_GET, HASH_PUT, HASH_PUTNEW, HASH_DELETE, HASH_FIRST, HASH_NEXT 40: } ACTION; 41: 42: /* Buffer Management structures */ 43: typedef struct _bufhead BUFHEAD; 44: 45: struct _bufhead { 46: BUFHEAD *prev; /* LRU links */ 47: BUFHEAD *next; /* LRU links */ 48: BUFHEAD *ovfl; /* Overflow page buffer header */ 49: u_int32_t addr; /* Address of this page */ 50: char *page; /* Actual page data */ 51: char flags; 52: #define BUF_MOD 0x0001 53: #define BUF_DISK 0x0002 54: #define BUF_BUCKET 0x0004 55: #define BUF_PIN 0x0008 56: }; 57: 58: #define IS_BUCKET(X) ((X) & BUF_BUCKET) 59: 60: typedef BUFHEAD **SEGMENT; 61: 62: /* Hash Table Information */ 63: typedef struct hashhdr { /* Disk resident portion */ 64: int32_t magic; /* Magic NO for hash tables */ 65: int32_t version; /* Version ID */ 66: u_int32_t lorder; /* Byte Order */ 67: int32_t bsize; /* Bucket/Page Size */ 68: int32_t bshift; /* Bucket shift */ 69: int32_t dsize; /* Directory Size */ 70: int32_t ssize; /* Segment Size */ 71: int32_t sshift; /* Segment shift */ 72: int32_t ovfl_point; /* Where overflow pages are being 73: * allocated */ 74: int32_t last_freed; /* Last overflow page freed */ 75: int32_t max_bucket; /* ID of Maximum bucket in use */ 76: int32_t high_mask; /* Mask to modulo into entire table */ 77: int32_t low_mask; /* Mask to modulo into lower half of 78: * table */ 79: int32_t ffactor; /* Fill factor */ 80: int32_t nkeys; /* Number of keys in hash table */ 81: int32_t hdrpages; /* Size of table header */ 82: int32_t h_charkey; /* value of hash(CHARKEY) */ 83: #define NCACHED 32 /* number of bit maps and spare 84: * points */ 85: int32_t spares[NCACHED];/* spare pages for overflow */ 86: u_int16_t bitmaps[NCACHED]; /* address of overflow page 87: * bitmaps */ 88: } HASHHDR; 89: 90: typedef struct htab { /* Memory resident data structure */ 91: HASHHDR hdr; /* Header */ 92: int nsegs; /* Number of allocated segments */ 93: int exsegs; /* Number of extra allocated 94: * segments */ 95: u_int32_t /* Hash function */ 96: (*hash)(const void *, size_t); 97: int flags; /* Flag values */ 98: int fp; /* File pointer */ 99: char *tmp_buf; /* Temporary Buffer for BIG data */ 100: char *tmp_key; /* Temporary Buffer for BIG keys */ 101: BUFHEAD *cpage; /* Current page */ 102: int cbucket; /* Current bucket */ 103: int cndx; /* Index of next item on cpage */ 104: int err; /* Error Number -- for DBM 105: * compatibility */ 106: int new_file; /* Indicates if fd is backing store 107: * or no */ 108: int save_file; /* Indicates whether we need to flush 109: * file at 110: * exit */ 111: u_int32_t *mapp[NCACHED]; /* Pointers to page maps */ 112: int nmaps; /* Initial number of bitmaps */ 113: int nbufs; /* Number of buffers left to 114: * allocate */ 115: BUFHEAD bufhead; /* Header of buffer lru list */ 116: SEGMENT *dir; /* Hash Bucket directory */ 117: } HTAB; 118: 119: /* 120: * Constants 121: */ 122: #define MAX_BSIZE 65536 /* 2^16 */ 123: #define MIN_BUFFERS 6 124: #define MINHDRSIZE 512 125: #define DEF_BUFSIZE 65536 /* 64 K */ 126: #define DEF_BUCKET_SIZE 4096 127: #define DEF_BUCKET_SHIFT 12 /* log2(BUCKET) */ 128: #define DEF_SEGSIZE 256 129: #define DEF_SEGSIZE_SHIFT 8 /* log2(SEGSIZE) */ 130: #define DEF_DIRSIZE 256 131: #define DEF_FFACTOR 65536 132: #define MIN_FFACTOR 4 133: #define SPLTMAX 8 134: #define CHARKEY "%$sniglet^&" 135: #define NUMKEY 1038583 136: #define BYTE_SHIFT 3 137: #define INT_TO_BYTE 2 138: #define INT_BYTE_SHIFT 5 139: #define ALL_SET ((u_int32_t)0xFFFFFFFF) 140: #define ALL_CLEAR 0 141: 142: #define PTROF(X) ((BUFHEAD *)((ptrdiff_t)(X)&~0x3)) 143: #define ISMOD(X) ((u_int32_t)(ptrdiff_t)(X)&0x1) 144: #define DOMOD(X) ((X) = (char *)((ptrdiff_t)(X)|0x1)) 145: #define ISDISK(X) ((u_int32_t)(ptrdiff_t)(X)&0x2) 146: #define DODISK(X) ((X) = (char *)((ptrdiff_t)(X)|0x2)) 147: 148: #define BITS_PER_MAP 32 149: 150: /* Given the address of the beginning of a big map, clear/set the nth bit */ 151: #define CLRBIT(A, N) ((A)[(N)/BITS_PER_MAP] &= ~(1<<((N)%BITS_PER_MAP))) 152: #define SETBIT(A, N) ((A)[(N)/BITS_PER_MAP] |= (1<<((N)%BITS_PER_MAP))) 153: #define ISSET(A, N) ((A)[(N)/BITS_PER_MAP] & (1<<((N)%BITS_PER_MAP))) 154: 155: /* Overflow management */ 156: /* 157: * Overflow page numbers are allocated per split point. At each doubling of 158: * the table, we can allocate extra pages. So, an overflow page number has 159: * the top 5 bits indicate which split point and the lower 11 bits indicate 160: * which page at that split point is indicated (pages within split points are 161: * numberered starting with 1). 162: */ 163: 164: #define SPLITSHIFT 11 165: #define SPLITMASK 0x7FF 166: #define SPLITNUM(N) (((u_int32_t)(N)) >> SPLITSHIFT) 167: #define OPAGENUM(N) ((N) & SPLITMASK) 168: #define OADDR_OF(S,O) ((u_int32_t)((u_int32_t)(S) << SPLITSHIFT) + (O)) 169: 170: #define BUCKET_TO_PAGE(B) \ 171: (B) + hashp->HDRPAGES + ((B) ? hashp->SPARES[__log2((B)+1)-1] : 0) 172: #define OADDR_TO_PAGE(B) \ 173: BUCKET_TO_PAGE ( (1 << SPLITNUM((B))) -1 ) + OPAGENUM((B)); 174: 175: /* 176: * page.h contains a detailed description of the page format. 177: * 178: * Normally, keys and data are accessed from offset tables in the top of 179: * each page which point to the beginning of the key and data. There are 180: * four flag values which may be stored in these offset tables which indicate 181: * the following: 182: * 183: * 184: * OVFLPAGE Rather than a key data pair, this pair contains 185: * the address of an overflow page. The format of 186: * the pair is: 187: * OVERFLOW_PAGE_NUMBER OVFLPAGE 188: * 189: * PARTIAL_KEY This must be the first key/data pair on a page 190: * and implies that page contains only a partial key. 191: * That is, the key is too big to fit on a single page 192: * so it starts on this page and continues on the next. 193: * The format of the page is: 194: * KEY_OFF PARTIAL_KEY OVFL_PAGENO OVFLPAGE 195: * 196: * KEY_OFF -- offset of the beginning of the key 197: * PARTIAL_KEY -- 1 198: * OVFL_PAGENO - page number of the next overflow page 199: * OVFLPAGE -- 0 200: * 201: * FULL_KEY This must be the first key/data pair on the page. It 202: * is used in two cases. 203: * 204: * Case 1: 205: * There is a complete key on the page but no data 206: * (because it wouldn't fit). The next page contains 207: * the data. 208: * 209: * Page format it: 210: * KEY_OFF FULL_KEY OVFL_PAGENO OVFL_PAGE 211: * 212: * KEY_OFF -- offset of the beginning of the key 213: * FULL_KEY -- 2 214: * OVFL_PAGENO - page number of the next overflow page 215: * OVFLPAGE -- 0 216: * 217: * Case 2: 218: * This page contains no key, but part of a large 219: * data field, which is continued on the next page. 220: * 221: * Page format it: 222: * DATA_OFF FULL_KEY OVFL_PAGENO OVFL_PAGE 223: * 224: * KEY_OFF -- offset of the beginning of the data on 225: * this page 226: * FULL_KEY -- 2 227: * OVFL_PAGENO - page number of the next overflow page 228: * OVFLPAGE -- 0 229: * 230: * FULL_KEY_DATA 231: * This must be the first key/data pair on the page. 232: * There are two cases: 233: * 234: * Case 1: 235: * This page contains a key and the beginning of the 236: * data field, but the data field is continued on the 237: * next page. 238: * 239: * Page format is: 240: * KEY_OFF FULL_KEY_DATA OVFL_PAGENO DATA_OFF 241: * 242: * KEY_OFF -- offset of the beginning of the key 243: * FULL_KEY_DATA -- 3 244: * OVFL_PAGENO - page number of the next overflow page 245: * DATA_OFF -- offset of the beginning of the data 246: * 247: * Case 2: 248: * This page contains the last page of a big data pair. 249: * There is no key, only the tail end of the data 250: * on this page. 251: * 252: * Page format is: 253: * DATA_OFF FULL_KEY_DATA <OVFL_PAGENO> <OVFLPAGE> 254: * 255: * DATA_OFF -- offset of the beginning of the data on 256: * this page 257: * FULL_KEY_DATA -- 3 258: * OVFL_PAGENO - page number of the next overflow page 259: * OVFLPAGE -- 0 260: * 261: * OVFL_PAGENO and OVFLPAGE are optional (they are 262: * not present if there is no next page). 263: */ 264: 265: #define OVFLPAGE 0 266: #define PARTIAL_KEY 1 267: #define FULL_KEY 2 268: #define FULL_KEY_DATA 3 269: #define REAL_KEY 4 270: 271: /* Short hands for accessing structure */ 272: #define BSIZE hdr.bsize 273: #define BSHIFT hdr.bshift 274: #define DSIZE hdr.dsize 275: #define SGSIZE hdr.ssize 276: #define SSHIFT hdr.sshift 277: #define LORDER hdr.lorder 278: #define OVFL_POINT hdr.ovfl_point 279: #define LAST_FREED hdr.last_freed 280: #define MAX_BUCKET hdr.max_bucket 281: #define FFACTOR hdr.ffactor 282: #define HIGH_MASK hdr.high_mask 283: #define LOW_MASK hdr.low_mask 284: #define NKEYS hdr.nkeys 285: #define HDRPAGES hdr.hdrpages 286: #define SPARES hdr.spares 287: #define BITMAPS hdr.bitmaps 288: #define VERSION hdr.version 289: #define MAGIC hdr.magic 290: #define NEXT_FREE hdr.next_free 291: #define H_CHARKEY hdr.h_charkey