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+/*-
+ * 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 errnum; /* Error Number -- for DBM
+ * compatibility */
+ 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[__hash_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