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/* |
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openisis - an open implementation of the CDS/ISIS database |
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Version 0.8.x (patchlevel see file Version) |
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Copyright (C) 2001-2003 by Erik Grziwotz, erik@openisis.org |
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|
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This library is free software; you can redistribute it and/or |
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modify it under the terms of the GNU Lesser General Public |
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License as published by the Free Software Foundation; either |
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version 2.1 of the License, or (at your option) any later version. |
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|
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This library is distributed in the hope that it will be useful, |
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but WITHOUT ANY WARRANTY; without even the implied warranty of |
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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Lesser General Public License for more details. |
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|
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You should have received a copy of the GNU Lesser General Public |
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License along with this library; if not, write to the Free Software |
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
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|
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see README for more information |
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EOH */ |
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#ifndef LDB_H |
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|
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/* |
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$Id: ldb.h,v 1.19 2003/04/08 00:20:52 kripke Exp $ |
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package interface of the general db access functions. |
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*/ |
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|
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#include "luti.h" |
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#include "lll.h" |
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|
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/* #define LDB_MAGIC 0x0FE91515 read OPENISIS */ |
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|
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|
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enum { /* MFR members */ |
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LMFR_MFN = 1, /* the rowid */ |
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LMFR_RECL, /* total external length (even), negative for locked record */ |
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LMFR_BWB, /* block of rec's previous version */ |
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LMFR_BWP, /* pos of " */ |
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LMFR_BASE, /* offset of contents area */ |
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LMFR_NVF, /* number of fields */ |
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LMFR_STAT, /* state, if != 0, about to be deleted */ |
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LMFR__FL, /* offset of repeated part */ |
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LMFR_TAG = 0, |
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LMFR_POS, |
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LMFR_LEN, |
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LMFR__RL /* length of repeated part */ |
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}; |
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|
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|
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/** |
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read a raw isis record by rowid. |
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the memory must be freed after usage. |
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*/ |
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extern int *ldb_readRec ( int db, int rowid ); |
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|
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|
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/** |
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numerical type for a records file position. |
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To support large DBs, this may be lll. |
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*/ |
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typedef int lxref; |
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|
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|
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/** |
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read a raw isis record by xref. |
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the memory must be freed after usage. |
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*/ |
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extern int *ldb_readRecAtOff ( int dbid, lxref off, int *nxtoff ); |
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|
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|
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|
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|
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/* |
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** ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ |
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** detailed search structures and functions |
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** |
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** ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ |
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*/ |
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|
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enum { |
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LDB_MAX_KEYLEN = 31, /* actually, it's 30 for isis-1 */ |
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LDB_TERMBUF = 128, /* ints */ |
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LDB_INDEXES = 2 |
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}; |
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|
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|
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/** |
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the isis-1 posting is an 64bit number. |
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In the file it's in big endian order, to allow ordering using memcmp. |
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In the LdbP we have native order to use native 64bit. |
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Until we need more bits for postings, we may use the 64bit type |
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provided by gcc and some other compilers. |
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|
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the 8 bytes are: highest 3 for the rowid, then 2 tag, then 3 pos. |
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the 3 pos bytes in turn are 1 byte for the occurence |
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and 2 bytes for the word count. |
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(e.g. value 2<<16 | 7 if term was found in the 7th word of |
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the 2nd occurence of field 'tag'). |
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we usually don't care, since for a near condition we always |
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want a small distance w/in the same occurence which may be |
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conveniently checked by the difference of 3 byte pos values. |
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|
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BUT NOTE: ... unfortunately we DO NEED one more bit for marking |
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postings during AND operations. we abuse the highest bit of the |
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word counter, since it's for sure useless for any reasonable |
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distance check. |
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*** BE CAREFUL WHEN COMPARING POSTINGS DURING "AND" OP *** |
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use the LDBP_xxM macros below. |
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*/ |
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typedef union { |
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char bytes[8]; |
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lll val; |
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} LdbP; |
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|
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|
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|
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/* all macros operate on pointers */ |
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/* access parts */ |
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#define LDBP_ROW( p ) (0xffffffL & (int)((p)->val >> 40)) |
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#define LDBP_TAG( p ) ( 0xffffL & (int)((p)->val >> 24)) |
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#define LDBP_POS( p ) (0xff7fffL & (int)((p)->val)) |
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#define LDBP_MARK( p ) ( 0x8000 & (int)((p)->val)) |
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|
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#define LDBP_SETMARK( p ) ((p)->val |= LLL( 0x8000)) |
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#define LDBP_CLRMARK( p ) ((p)->val &= LLL(0xffffffffffff7fff)) |
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/* value w/o the mark bit */ |
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#define LDBP_IGNMARK( p ) ((p)->val & LLL(0xffffffffffff7fff)) |
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|
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/* compare according to rowid, tag, pos */ |
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#define LDBP_EQ( a, b ) ((a)->val == (b)->val) |
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#define LDBP_GT( a, b ) ((a)->val > (b)->val) |
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/* compare IGNORING MARK according to rowid, tag, pos */ |
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#define LDBP_EQM( a, b ) (LDBP_IGNMARK(a) == LDBP_IGNMARK(b)) |
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#define LDBP_GTM( a, b ) (LDBP_IGNMARK(a) > LDBP_IGNMARK(b)) |
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|
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/* manipulation: set bottom / top for row of given posting */ |
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#define LDBP_SETROWBOT( d, s ) ((d)->val = (s)->val & LLL(0xffffff0000000000)) |
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#define LDBP_SETROWTOP( d, s ) ((d)->val = (s)->val | LLL( 0xffffffffff)) |
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|
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|
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/** |
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postings come in arrays with some header. |
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The standard structure gives a 8k buffer, |
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but member len may give other actual length. |
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*/ |
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typedef struct { |
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short mode; /* in: merge flags */ |
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short near; /* in: near distance; in OR mode: collect pos info */ |
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int tag; /* in: tag, to which postings are restricted */ |
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int skp; /* in: ignore mfns < skp */ |
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int len; /* in: length (# of postings) of buffer (if 0 : default length) */ |
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int fil; /* io: number of postings actually used */ |
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int cut; /* io: min mfn ignored due to buffer length */ |
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LdbP p[OPENISIS_SETLEN]; |
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/** |
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8 bytes as in IFP file: mfn[3],tag[2],occ[1],cnt[2] |
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highest bit of cnt (1LL<<15) is used as mark |
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*/ |
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} LdbPost; |
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|
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enum { |
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LDB_OR, |
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LDB_AND, |
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LDB_NOT, /* like AND, but keep unmarked postings */ |
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LDB_PFX = 4, /* prefix match */ |
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LDB_KEEPMARKS = 8 /* do not compact after AND/NOT */ |
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}; |
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|
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enum { |
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LDB_NEAR_F = 0x7fff, /* the (F): same occurence of field */ |
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LDB_NEAR_G = -0x8000 /* the (G): same field */ |
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}; |
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|
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/** |
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*/ |
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extern int ldb_search ( int db, const char *key, LdbPost *post, |
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OpenIsisRec *rec ); |
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|
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|
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extern int ldb_p2s ( OpenIsisSet *set, LdbPost *post ); |
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|
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extern Db* ldb_getdb (int dbid); |
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|
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#define LDB_H |
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#endif /* LDB_H */ |