/[webpac]/trunk2/openisis/ldb.h
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Contents of /trunk2/openisis/ldb.h

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Revision 337 - (show annotations)
Thu Jun 10 19:22:40 2004 UTC (15 years, 7 months ago) by dpavlin
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File size: 5624 byte(s)
new trunk for webpac v2

1 /*
2 openisis - an open implementation of the CDS/ISIS database
3 Version 0.8.x (patchlevel see file Version)
4 Copyright (C) 2001-2003 by Erik Grziwotz, erik@openisis.org
5
6 This library is free software; you can redistribute it and/or
7 modify it under the terms of the GNU Lesser General Public
8 License as published by the Free Software Foundation; either
9 version 2.1 of the License, or (at your option) any later version.
10
11 This library is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Lesser General Public License for more details.
15
16 You should have received a copy of the GNU Lesser General Public
17 License along with this library; if not, write to the Free Software
18 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
19
20 see README for more information
21 EOH */
22 #ifndef LDB_H
23
24 /*
25 $Id: ldb.h,v 1.19 2003/04/08 00:20:52 kripke Exp $
26 package interface of the general db access functions.
27 */
28
29 #include "luti.h"
30 #include "lll.h"
31
32 /* #define LDB_MAGIC 0x0FE91515 read OPENISIS */
33
34
35 enum { /* MFR members */
36 LMFR_MFN = 1, /* the rowid */
37 LMFR_RECL, /* total external length (even), negative for locked record */
38 LMFR_BWB, /* block of rec's previous version */
39 LMFR_BWP, /* pos of " */
40 LMFR_BASE, /* offset of contents area */
41 LMFR_NVF, /* number of fields */
42 LMFR_STAT, /* state, if != 0, about to be deleted */
43 LMFR__FL, /* offset of repeated part */
44 LMFR_TAG = 0,
45 LMFR_POS,
46 LMFR_LEN,
47 LMFR__RL /* length of repeated part */
48 };
49
50
51 /**
52 read a raw isis record by rowid.
53 the memory must be freed after usage.
54 */
55 extern int *ldb_readRec ( int db, int rowid );
56
57
58 /**
59 numerical type for a records file position.
60 To support large DBs, this may be lll.
61 */
62 typedef int lxref;
63
64
65 /**
66 read a raw isis record by xref.
67 the memory must be freed after usage.
68 */
69 extern int *ldb_readRecAtOff ( int dbid, lxref off, int *nxtoff );
70
71
72
73
74 /*
75 ** ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
76 ** detailed search structures and functions
77 **
78 ** ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
79 */
80
81 enum {
82 LDB_MAX_KEYLEN = 31, /* actually, it's 30 for isis-1 */
83 LDB_TERMBUF = 128, /* ints */
84 LDB_INDEXES = 2
85 };
86
87
88 /**
89 the isis-1 posting is an 64bit number.
90 In the file it's in big endian order, to allow ordering using memcmp.
91 In the LdbP we have native order to use native 64bit.
92 Until we need more bits for postings, we may use the 64bit type
93 provided by gcc and some other compilers.
94
95 the 8 bytes are: highest 3 for the rowid, then 2 tag, then 3 pos.
96 the 3 pos bytes in turn are 1 byte for the occurence
97 and 2 bytes for the word count.
98 (e.g. value 2<<16 | 7 if term was found in the 7th word of
99 the 2nd occurence of field 'tag').
100 we usually don't care, since for a near condition we always
101 want a small distance w/in the same occurence which may be
102 conveniently checked by the difference of 3 byte pos values.
103
104 BUT NOTE: ... unfortunately we DO NEED one more bit for marking
105 postings during AND operations. we abuse the highest bit of the
106 word counter, since it's for sure useless for any reasonable
107 distance check.
108 *** BE CAREFUL WHEN COMPARING POSTINGS DURING "AND" OP ***
109 use the LDBP_xxM macros below.
110 */
111 typedef union {
112 char bytes[8];
113 lll val;
114 } LdbP;
115
116
117
118 /* all macros operate on pointers */
119 /* access parts */
120 #define LDBP_ROW( p ) (0xffffffL & (int)((p)->val >> 40))
121 #define LDBP_TAG( p ) ( 0xffffL & (int)((p)->val >> 24))
122 #define LDBP_POS( p ) (0xff7fffL & (int)((p)->val))
123 #define LDBP_MARK( p ) ( 0x8000 & (int)((p)->val))
124
125 #define LDBP_SETMARK( p ) ((p)->val |= LLL( 0x8000))
126 #define LDBP_CLRMARK( p ) ((p)->val &= LLL(0xffffffffffff7fff))
127 /* value w/o the mark bit */
128 #define LDBP_IGNMARK( p ) ((p)->val & LLL(0xffffffffffff7fff))
129
130 /* compare according to rowid, tag, pos */
131 #define LDBP_EQ( a, b ) ((a)->val == (b)->val)
132 #define LDBP_GT( a, b ) ((a)->val > (b)->val)
133 /* compare IGNORING MARK according to rowid, tag, pos */
134 #define LDBP_EQM( a, b ) (LDBP_IGNMARK(a) == LDBP_IGNMARK(b))
135 #define LDBP_GTM( a, b ) (LDBP_IGNMARK(a) > LDBP_IGNMARK(b))
136
137 /* manipulation: set bottom / top for row of given posting */
138 #define LDBP_SETROWBOT( d, s ) ((d)->val = (s)->val & LLL(0xffffff0000000000))
139 #define LDBP_SETROWTOP( d, s ) ((d)->val = (s)->val | LLL( 0xffffffffff))
140
141
142 /**
143 postings come in arrays with some header.
144 The standard structure gives a 8k buffer,
145 but member len may give other actual length.
146 */
147 typedef struct {
148 short mode; /* in: merge flags */
149 short near; /* in: near distance; in OR mode: collect pos info */
150 int tag; /* in: tag, to which postings are restricted */
151 int skp; /* in: ignore mfns < skp */
152 int len; /* in: length (# of postings) of buffer (if 0 : default length) */
153 int fil; /* io: number of postings actually used */
154 int cut; /* io: min mfn ignored due to buffer length */
155 LdbP p[OPENISIS_SETLEN];
156 /**
157 8 bytes as in IFP file: mfn[3],tag[2],occ[1],cnt[2]
158 highest bit of cnt (1LL<<15) is used as mark
159 */
160 } LdbPost;
161
162 enum {
163 LDB_OR,
164 LDB_AND,
165 LDB_NOT, /* like AND, but keep unmarked postings */
166 LDB_PFX = 4, /* prefix match */
167 LDB_KEEPMARKS = 8 /* do not compact after AND/NOT */
168 };
169
170 enum {
171 LDB_NEAR_F = 0x7fff, /* the (F): same occurence of field */
172 LDB_NEAR_G = -0x8000 /* the (G): same field */
173 };
174
175 /**
176 */
177 extern int ldb_search ( int db, const char *key, LdbPost *post,
178 OpenIsisRec *rec );
179
180
181 extern int ldb_p2s ( OpenIsisSet *set, LdbPost *post );
182
183 extern Db* ldb_getdb (int dbid);
184
185 #define LDB_H
186 #endif /* LDB_H */

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