locate/locatedb.h

   1 /* locatedb.h -- declarations for the locate database
   2    Copyright (C) 1994 Free Software Foundation, Inc.
   3
   4    This program is free software; you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation; either version 2, or (at your option)
   7    any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program; if not, write to the Free Software
  16    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  */
  17
  18 #ifndef _LOCATEDB_H
  19 #define _LOCATEDB_H 1
  20
  21 /* The magic string at the start of a locate database, to make sure
  22    it's in the right format.  The 02 is the database format version number.
  23    This string has the same format as a database entry, but you can't
  24    concatenate databases even if you remove it, since the differential count
  25    in the first entry of the second database will be wrong.  */
  26 #define LOCATEDB_MAGIC "\0LOCATE02"
  27
  28 /* Common-prefix length differences in the ranges
  29    0..127, -127..-1 (0x00..0x7f, 0x81..0xff) fit into one byte.
  30    This value (which is -128) indicates that the difference is
  31    too large to fit into one byte, and a two-byte integer follows.  */
  32 #define LOCATEDB_ESCAPE 0x80
  33
  34 /* These are used for old, bigram-encoded databases:  */
  35
  36 /* Means the differential count follows in a 2-byte int instead. */
  37 #define LOCATEDB_OLD_ESCAPE     30
  38
  39 /* Offset added to differential counts to encode them as positive numbers.  */
  40 #define LOCATEDB_OLD_OFFSET     14
  41
  42 #endif /* !_LOCATEDB_H */