| /*- |
| * Copyright (c) 1990, 1993, 1994 |
| * The Regents of the University of California. All rights reserved. |
| * |
| * This code is derived from software contributed to Berkeley by |
| * Margo Seltzer. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * 1. Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * 2. Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in the |
| * documentation and/or other materials provided with the distribution. |
| * 3. ***REMOVED*** - see |
| * ftp://ftp.cs.berkeley.edu/pub/4bsd/README.Impt.License.Change |
| * 4. Neither the name of the University nor the names of its contributors |
| * may be used to endorse or promote products derived from this software |
| * without specific prior written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
| * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
| * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
| * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
| * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
| * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
| * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| * SUCH DAMAGE. |
| * |
| * @(#)hash.h 8.3 (Berkeley) 5/31/94 |
| */ |
| |
| /* Operations */ |
| |
| #include <stdio.h> |
| #include "mcom_db.h" |
| typedef enum { |
| HASH_GET, |
| HASH_PUT, |
| HASH_PUTNEW, |
| HASH_DELETE, |
| HASH_FIRST, |
| HASH_NEXT |
| } ACTION; |
| |
| /* Buffer Management structures */ |
| typedef struct _bufhead BUFHEAD; |
| |
| struct _bufhead { |
| BUFHEAD *prev; /* LRU links */ |
| BUFHEAD *next; /* LRU links */ |
| BUFHEAD *ovfl; /* Overflow page buffer header */ |
| uint32 addr; /* Address of this page */ |
| char *page; /* Actual page data */ |
| char is_disk; |
| char flags; |
| #define BUF_MOD 0x0001 |
| #define BUF_DISK 0x0002 |
| #define BUF_BUCKET 0x0004 |
| #define BUF_PIN 0x0008 |
| }; |
| |
| #define IS_BUCKET(X) ((X)&BUF_BUCKET) |
| |
| typedef BUFHEAD **SEGMENT; |
| |
| typedef int DBFILE_PTR; |
| #define NO_FILE -1 |
| #ifdef macintosh |
| #define DBFILE_OPEN(path, flag, mode) open((path), flag) |
| #define EXISTS(path) |
| #else |
| #define DBFILE_OPEN(path, flag, mode) open((path), (flag), (mode)) |
| #endif |
| /* Hash Table Information */ |
| typedef struct hashhdr { /* Disk resident portion */ |
| int32 magic; /* Magic NO for hash tables */ |
| int32 version; /* Version ID */ |
| uint32 lorder; /* Byte Order */ |
| int32 bsize; /* Bucket/Page Size */ |
| int32 bshift; /* Bucket shift */ |
| int32 dsize; /* Directory Size */ |
| int32 ssize; /* Segment Size */ |
| int32 sshift; /* Segment shift */ |
| int32 ovfl_point; /* Where overflow pages are being |
| * allocated */ |
| int32 last_freed; /* Last overflow page freed */ |
| int32 max_bucket; /* ID of Maximum bucket in use */ |
| int32 high_mask; /* Mask to modulo into entire table */ |
| int32 low_mask; /* Mask to modulo into lower half of |
| * table */ |
| int32 ffactor; /* Fill factor */ |
| int32 nkeys; /* Number of keys in hash table */ |
| int32 hdrpages; /* Size of table header */ |
| uint32 h_charkey; /* value of hash(CHARKEY) */ |
| #define NCACHED 32 /* number of bit maps and spare \ |
| * points */ |
| int32 spares[NCACHED]; /* spare pages for overflow */ |
| uint16 bitmaps[NCACHED]; /* address of overflow page |
| * bitmaps */ |
| } HASHHDR; |
| |
| typedef struct htab { /* Memory resident data structure */ |
| HASHHDR hdr; /* Header */ |
| int nsegs; /* Number of allocated segments */ |
| int exsegs; /* Number of extra allocated |
| * segments */ |
| uint32 /* Hash function */ |
| (*hash)(const void *, size_t); |
| int flags; /* Flag values */ |
| DBFILE_PTR fp; /* File pointer */ |
| char *filename; |
| char *tmp_buf; /* Temporary Buffer for BIG data */ |
| char *tmp_key; /* Temporary Buffer for BIG keys */ |
| BUFHEAD *cpage; /* Current page */ |
| int cbucket; /* Current bucket */ |
| int cndx; /* Index of next item on cpage */ |
| int dbmerrno; /* Error Number -- for DBM |
| * compatability */ |
| int new_file; /* Indicates if fd is backing store |
| * or no */ |
| int save_file; /* Indicates whether we need to flush |
| * file at |
| * exit */ |
| uint32 *mapp[NCACHED]; /* Pointers to page maps */ |
| int nmaps; /* Initial number of bitmaps */ |
| int nbufs; /* Number of buffers left to |
| * allocate */ |
| BUFHEAD bufhead; /* Header of buffer lru list */ |
| SEGMENT *dir; /* Hash Bucket directory */ |
| off_t file_size; /* in bytes */ |
| char is_temp; /* unlink file on close */ |
| char updateEOF; /* force EOF update on flush */ |
| } HTAB; |
| |
| /* |
| * Constants |
| */ |
| #define DATABASE_CORRUPTED_ERROR -999 /* big ugly abort, delete database */ |
| #define OLD_MAX_BSIZE 65536 /* 2^16 */ |
| #define MAX_BSIZE 32l * 1024l /* 2^15 */ |
| #define MIN_BUFFERS 6 |
| #define MINHDRSIZE 512 |
| #define DEF_BUFSIZE 65536l /* 64 K */ |
| #define DEF_BUCKET_SIZE 4096 |
| #define DEF_BUCKET_SHIFT 12 /* log2(BUCKET) */ |
| #define DEF_SEGSIZE 256 |
| #define DEF_SEGSIZE_SHIFT 8 /* log2(SEGSIZE) */ |
| #define DEF_DIRSIZE 256 |
| #define DEF_FFACTOR 65536l |
| #define MIN_FFACTOR 4 |
| #define SPLTMAX 8 |
| #define CHARKEY "%$sniglet^&" |
| #define NUMKEY 1038583l |
| #define BYTE_SHIFT 3 |
| #define INT_TO_BYTE 2 |
| #define INT_BYTE_SHIFT 5 |
| #define ALL_SET ((uint32)0xFFFFFFFF) |
| #define ALL_CLEAR 0 |
| |
| #define PTROF(X) ((ptrdiff_t)(X) == BUF_DISK ? 0 : (X)) |
| #define ISDISK(X) ((X) ? ((ptrdiff_t)(X) == BUF_DISK ? BUF_DISK \ |
| : (X)->is_disk) \ |
| : 0) |
| |
| #define BITS_PER_MAP 32 |
| |
| /* Given the address of the beginning of a big map, clear/set the nth bit */ |
| #define CLRBIT(A, N) ((A)[(N) / BITS_PER_MAP] &= ~(1 << ((N) % BITS_PER_MAP))) |
| #define SETBIT(A, N) ((A)[(N) / BITS_PER_MAP] |= (1 << ((N) % BITS_PER_MAP))) |
| #define ISSET(A, N) ((A)[(N) / BITS_PER_MAP] & (1 << ((N) % BITS_PER_MAP))) |
| |
| /* Overflow management */ |
| /* |
| * Overflow page numbers are allocated per split point. At each doubling of |
| * the table, we can allocate extra pages. So, an overflow page number has |
| * the top 5 bits indicate which split point and the lower 11 bits indicate |
| * which page at that split point is indicated (pages within split points are |
| * numberered starting with 1). |
| */ |
| |
| #define SPLITSHIFT 11 |
| #define SPLITMASK 0x7FF |
| #define SPLITNUM(N) (((uint32)(N)) >> SPLITSHIFT) |
| #define OPAGENUM(N) ((N)&SPLITMASK) |
| #define OADDR_OF(S, O) ((uint32)((uint32)(S) << SPLITSHIFT) + (O)) |
| |
| #define BUCKET_TO_PAGE(B) \ |
| (B) + hashp->HDRPAGES + ((B) ? hashp->SPARES[dbm_log2((uint32)((B) + 1)) - 1] : 0) |
| #define OADDR_TO_PAGE(B) \ |
| BUCKET_TO_PAGE((1 << SPLITNUM((B))) - 1) + OPAGENUM((B)); |
| |
| /* |
| * page.h contains a detailed description of the page format. |
| * |
| * Normally, keys and data are accessed from offset tables in the top of |
| * each page which point to the beginning of the key and data. There are |
| * four flag values which may be stored in these offset tables which indicate |
| * the following: |
| * |
| * |
| * OVFLPAGE Rather than a key data pair, this pair contains |
| * the address of an overflow page. The format of |
| * the pair is: |
| * OVERFLOW_PAGE_NUMBER OVFLPAGE |
| * |
| * PARTIAL_KEY This must be the first key/data pair on a page |
| * and implies that page contains only a partial key. |
| * That is, the key is too big to fit on a single page |
| * so it starts on this page and continues on the next. |
| * The format of the page is: |
| * KEY_OFF PARTIAL_KEY OVFL_PAGENO OVFLPAGE |
| * |
| * KEY_OFF -- offset of the beginning of the key |
| * PARTIAL_KEY -- 1 |
| * OVFL_PAGENO - page number of the next overflow page |
| * OVFLPAGE -- 0 |
| * |
| * FULL_KEY This must be the first key/data pair on the page. It |
| * is used in two cases. |
| * |
| * Case 1: |
| * There is a complete key on the page but no data |
| * (because it wouldn't fit). The next page contains |
| * the data. |
| * |
| * Page format it: |
| * KEY_OFF FULL_KEY OVFL_PAGENO OVFL_PAGE |
| * |
| * KEY_OFF -- offset of the beginning of the key |
| * FULL_KEY -- 2 |
| * OVFL_PAGENO - page number of the next overflow page |
| * OVFLPAGE -- 0 |
| * |
| * Case 2: |
| * This page contains no key, but part of a large |
| * data field, which is continued on the next page. |
| * |
| * Page format it: |
| * DATA_OFF FULL_KEY OVFL_PAGENO OVFL_PAGE |
| * |
| * KEY_OFF -- offset of the beginning of the data on |
| * this page |
| * FULL_KEY -- 2 |
| * OVFL_PAGENO - page number of the next overflow page |
| * OVFLPAGE -- 0 |
| * |
| * FULL_KEY_DATA |
| * This must be the first key/data pair on the page. |
| * There are two cases: |
| * |
| * Case 1: |
| * This page contains a key and the beginning of the |
| * data field, but the data field is continued on the |
| * next page. |
| * |
| * Page format is: |
| * KEY_OFF FULL_KEY_DATA OVFL_PAGENO DATA_OFF |
| * |
| * KEY_OFF -- offset of the beginning of the key |
| * FULL_KEY_DATA -- 3 |
| * OVFL_PAGENO - page number of the next overflow page |
| * DATA_OFF -- offset of the beginning of the data |
| * |
| * Case 2: |
| * This page contains the last page of a big data pair. |
| * There is no key, only the tail end of the data |
| * on this page. |
| * |
| * Page format is: |
| * DATA_OFF FULL_KEY_DATA <OVFL_PAGENO> <OVFLPAGE> |
| * |
| * DATA_OFF -- offset of the beginning of the data on |
| * this page |
| * FULL_KEY_DATA -- 3 |
| * OVFL_PAGENO - page number of the next overflow page |
| * OVFLPAGE -- 0 |
| * |
| * OVFL_PAGENO and OVFLPAGE are optional (they are |
| * not present if there is no next page). |
| */ |
| |
| #define OVFLPAGE 0 |
| #define PARTIAL_KEY 1 |
| #define FULL_KEY 2 |
| #define FULL_KEY_DATA 3 |
| #define REAL_KEY 4 |
| |
| /* Short hands for accessing structure */ |
| #undef BSIZE |
| #define BSIZE hdr.bsize |
| #undef BSHIFT |
| #define BSHIFT hdr.bshift |
| #define DSIZE hdr.dsize |
| #define SGSIZE hdr.ssize |
| #define SSHIFT hdr.sshift |
| #define LORDER hdr.lorder |
| #define OVFL_POINT hdr.ovfl_point |
| #define LAST_FREED hdr.last_freed |
| #define MAX_BUCKET hdr.max_bucket |
| #define FFACTOR hdr.ffactor |
| #define HIGH_MASK hdr.high_mask |
| #define LOW_MASK hdr.low_mask |
| #define NKEYS hdr.nkeys |
| #define HDRPAGES hdr.hdrpages |
| #define SPARES hdr.spares |
| #define BITMAPS hdr.bitmaps |
| #define VERSION hdr.version |
| #define MAGIC hdr.magic |
| #define NEXT_FREE hdr.next_free |
| #define H_CHARKEY hdr.h_charkey |
| |
| extern uint32 (*dbm_default_hash)(const void *, size_t); |
| void dbm_buf_init(HTAB *hashp, int32 nbytes); |
| int dbm_big_delete(HTAB *hashp, BUFHEAD *bufp); |
| BUFHEAD *dbm_get_buf(HTAB *hashp, uint32 addr, BUFHEAD *prev_bp, int newpage); |
| uint32 dbm_call_hash(HTAB *hashp, char *k, size_t len); |
| #include "page.h" |
| extern int dbm_big_split(HTAB *hashp, BUFHEAD *op, BUFHEAD *np, |
| BUFHEAD *big_keyp, uint32 addr, uint32 obucket, SPLIT_RETURN *ret); |
| void dbm_free_ovflpage(HTAB *hashp, BUFHEAD *obufp); |
| BUFHEAD *dbm_add_ovflpage(HTAB *hashp, BUFHEAD *bufp); |
| int dbm_big_insert(HTAB *hashp, BUFHEAD *bufp, const DBT *key, const DBT *val); |
| int dbm_expand_table(HTAB *hashp); |
| uint32 dbm_log2(uint32 num); |
| void dbm_reclaim_buf(HTAB *hashp, BUFHEAD *bp); |
| int dbm_get_page(HTAB *hashp, char *p, uint32 bucket, int is_bucket, int is_disk, int is_bitmap); |
| int dbm_put_page(HTAB *hashp, char *p, uint32 bucket, int is_bucket, int is_bitmap); |
| int dbm_ibitmap(HTAB *hashp, int pnum, int nbits, int ndx); |
| int dbm_buf_free(HTAB *hashp, int do_free, int to_disk); |
| int dbm_find_bigpair(HTAB *hashp, BUFHEAD *bufp, int ndx, char *key, int size); |
| uint16 dbm_find_last_page(HTAB *hashp, BUFHEAD **bpp); |
| int dbm_addel(HTAB *hashp, BUFHEAD *bufp, const DBT *key, const DBT *val); |
| int dbm_big_return(HTAB *hashp, BUFHEAD *bufp, int ndx, DBT *val, int set_current); |
| int dbm_delpair(HTAB *hashp, BUFHEAD *bufp, int ndx); |
| int dbm_big_keydata(HTAB *hashp, BUFHEAD *bufp, DBT *key, DBT *val, int set); |
| int dbm_split_page(HTAB *hashp, uint32 obucket, uint32 nbucket); |