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dpavlin |
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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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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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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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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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see README for more information |
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EOH */ |
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#ifndef LBT_H |
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/* |
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$Id: lbt.h,v 1.12 2003/05/27 11:03:30 kripke Exp $ |
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package interface of the btree. |
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see Lehmann/Yao or the GiST for how it works. |
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*/ |
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#include "ldb.h" /* LdbPost */ |
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/** |
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key comparision function. |
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however, we still assume that two keys have to be identical |
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in length and bytes to be equal. |
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*/ |
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typedef int lbt_comp ( const unsigned char *a, const unsigned char *b, |
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unsigned int l ); |
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/** |
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variables: |
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4 bits: #bytes for value 8+(0..15) |
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2 bits: blocksize 1024<<(0..3) |
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max key length (4..255) |
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collation (comparision function) 0..255 |
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*/ |
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typedef struct Idx { /* actually it's a B-L-Tree ;) */ |
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int fd; /* the file */ |
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int flg; /* flags: writeable, batch */ |
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unsigned char typ; /* type: bsz, ifp, flags */ |
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unsigned char key; /* max key length */ |
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unsigned char col; /* collation */ |
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unsigned char dpt; /* depth (level of root over bottom > 0) */ |
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lbt_comp *cmp; /* comparision function */ |
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/* following members (and the depth above) are set automatically. |
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they are going to stay and you may check them, if you're interested. |
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*/ |
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unsigned vsz; /* ifp size computed from type */ |
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unsigned bsz; /* block size computed from type */ |
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unsigned len; /* # blocks in index */ |
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/* following members are considered internal. |
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if you import lbt and rely on them, don't blame me if they change. |
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*/ |
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unsigned hlen; /* hash length */ |
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unsigned clen; /* cache length */ |
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struct Block *root; /* the root */ |
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struct Block **hash; /* hash array */ |
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struct Block *lru[4]; /* least recently used list for lowest levels */ |
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struct Block *mru[4]; /* tail of lru list (most recently used) */ |
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struct Chunk *mem; |
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struct Batch *bat; |
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} Idx; |
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enum { /* btree flags */ |
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LBT_WRITE = 0x01 /* open for writing */ |
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}; |
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enum { /* btree type */ |
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LBT_BLK1K = 0x00, /* 1K blocks */ |
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LBT_BLK2K = 0x10, /* 2K blocks */ |
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LBT_BLK4K = 0x20, /* 4K blocks */ |
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LBT_BLK8K = 0x30, /* 8K blocks */ |
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LBT_CMPRS = 0x80 /* compressed keys */ |
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}; |
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/** |
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initialise from an already open fd. |
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*/ |
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extern int lbt_init ( Idx *bt ); |
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/** |
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flush and release any cache, close fd. |
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*/ |
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extern void lbt_close ( Idx *bt ); |
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extern int lbt_batch ( Idx *bt, unsigned char pctfree ); |
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extern int lbt_batchval ( Idx *bt, Key *key ); |
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extern int lbt_add ( Idx *bt, Key *key ); |
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extern int lbt_del ( Idx *bt, Key *key ); |
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extern int lbt_loop ( Idx *bt, DXLoop *l ); |
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extern int lbt_search ( Idx *bt, Key *key, LdbPost *post, Rec *rec ); |
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/* half public ... ??? */ |
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extern void cXMkVal ( Idx *bt, Val *val, Hit *hit ); |
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#define LBT_H |
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#endif /* LBT_H */ |