296 lines
10 KiB
C
296 lines
10 KiB
C
/* $NetBSD: hash.h,v 1.5 1995/02/27 13:22:08 cgd Exp $ */
|
|
|
|
/*-
|
|
* 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. All advertising materials mentioning features or use of this software
|
|
* must display the following acknowledgement:
|
|
* This product includes software developed by the University of
|
|
* California, Berkeley and its contributors.
|
|
* 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 */
|
|
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 */
|
|
u_int32_t addr; /* Address of this page */
|
|
char *page; /* Actual page data */
|
|
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;
|
|
|
|
/* Hash Table Information */
|
|
typedef struct hashhdr { /* Disk resident portion */
|
|
int magic; /* Magic NO for hash tables */
|
|
int version; /* Version ID */
|
|
u_int32_t lorder; /* Byte Order */
|
|
int bsize; /* Bucket/Page Size */
|
|
int bshift; /* Bucket shift */
|
|
int dsize; /* Directory Size */
|
|
int ssize; /* Segment Size */
|
|
int sshift; /* Segment shift */
|
|
int ovfl_point; /* Where overflow pages are being
|
|
* allocated */
|
|
int last_freed; /* Last overflow page freed */
|
|
int max_bucket; /* ID of Maximum bucket in use */
|
|
int high_mask; /* Mask to modulo into entire table */
|
|
int low_mask; /* Mask to modulo into lower half of
|
|
* table */
|
|
int ffactor; /* Fill factor */
|
|
int nkeys; /* Number of keys in hash table */
|
|
int hdrpages; /* Size of table header */
|
|
int h_charkey; /* value of hash(CHARKEY) */
|
|
#define NCACHED 32 /* number of bit maps and spare
|
|
* points */
|
|
int spares[NCACHED];/* spare pages for overflow */
|
|
u_int16_t 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 */
|
|
u_int32_t /* Hash function */
|
|
(*hash)__P((const void *, size_t));
|
|
int flags; /* Flag values */
|
|
int fp; /* File pointer */
|
|
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 errno; /* 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 */
|
|
u_int32_t *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 */
|
|
} HTAB;
|
|
|
|
/*
|
|
* Constants
|
|
*/
|
|
#define MAX_BSIZE 65536 /* 2^16 */
|
|
#define MIN_BUFFERS 6
|
|
#define MINHDRSIZE 512
|
|
#define DEF_BUFSIZE 65536 /* 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 65536
|
|
#define MIN_FFACTOR 4
|
|
#define SPLTMAX 8
|
|
#define CHARKEY "%$sniglet^&"
|
|
#define NUMKEY 1038583
|
|
#define BYTE_SHIFT 3
|
|
#define INT_TO_BYTE 2
|
|
#define INT_BYTE_SHIFT 5
|
|
#define ALL_SET ((u_int32_t)0xFFFFFFFF)
|
|
#define ALL_CLEAR 0
|
|
|
|
#define PTROF(X) ((BUFHEAD *)((ptrdiff_t)(X)&~0x3))
|
|
#define ISMOD(X) ((u_int32_t)(ptrdiff_t)(X)&0x1)
|
|
#define DOMOD(X) ((X) = (char *)((ptrdiff_t)(X)|0x1))
|
|
#define ISDISK(X) ((u_int32_t)(ptrdiff_t)(X)&0x2)
|
|
#define DODISK(X) ((X) = (char *)((ptrdiff_t)(X)|0x2))
|
|
|
|
#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) (((u_int32_t)(N)) >> SPLITSHIFT)
|
|
#define OPAGENUM(N) ((N) & SPLITMASK)
|
|
#define OADDR_OF(S,O) ((u_int32_t)((u_int32_t)(S) << SPLITSHIFT) + (O))
|
|
|
|
#define BUCKET_TO_PAGE(B) \
|
|
(B) + hashp->HDRPAGES + ((B) ? hashp->SPARES[__log2((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 */
|
|
#define BSIZE hdr.bsize
|
|
#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
|