xapian-core/include/xapian/types.h

   1 /** @file xapian/types.h
   2  *  @brief typedefs for Xapian
   3  */
   4 /* Copyright (C) 2007,2010,2011,2013,2014,2017 Olly Betts
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License as
   8  * published by the Free Software Foundation; either version 2 of the
   9  * License, or (at your option) any later version.
  10  *
  11  * This program 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
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
  19  */
  20
  21 #ifndef XAPIAN_INCLUDED_TYPES_H
  22 #define XAPIAN_INCLUDED_TYPES_H
  23
  24 #if !defined XAPIAN_IN_XAPIAN_H && !defined XAPIAN_LIB_BUILD
  25 # error "Never use <xapian/types.h> directly; include <xapian.h> instead."
  26 #endif
  27
  28 #include <xapian/version.h>
  29
  30 namespace Xapian {
  31
  32 /** A count of documents.
  33  *
  34  *  This is used to hold values such as the number of documents in a database
  35  *  and the frequency of a term in the database.
  36  */
  37 typedef unsigned XAPIAN_DOCID_BASE_TYPE doccount;
  38
  39 /** A signed difference between two counts of documents.
  40  *
  41  *  This is used by the Xapian classes which are STL containers of documents
  42  *  for "difference_type".
  43  */
  44 typedef XAPIAN_DOCID_BASE_TYPE doccount_diff;
  45
  46 /** A unique identifier for a document.
  47  *
  48  *  Docid 0 is invalid, providing an "out of range" value which can be
  49  *  used to mean "not a valid document".
  50  */
  51 typedef unsigned XAPIAN_DOCID_BASE_TYPE docid;
  52
  53 /** A normalised document length.
  54  *
  55  *  The normalised document length is the document length divided by the
  56  *  average document length in the database.
  57  */
  58 typedef double doclength;
  59
  60 /** A counts of terms.
  61  *
  62  *  This is used to hold values such as the Within Document Frequency (wdf).
  63  */
  64 typedef unsigned XAPIAN_TERMCOUNT_BASE_TYPE termcount;
  65
  66 /** A signed difference between two counts of terms.
  67  *
  68  *  This is used by the Xapian classes which are STL containers of terms
  69  *  for "difference_type".
  70  */
  71 typedef XAPIAN_TERMCOUNT_BASE_TYPE termcount_diff;
  72
  73 /** A term position within a document or query.
  74  */
  75 typedef unsigned termpos;
  76
  77 /** A signed difference between two term positions.
  78  *
  79  *  This is used by the Xapian classes which are STL containers of positions
  80  *  for "difference_type".
  81  */
  82 typedef int termpos_diff; /* FIXME: can overflow. */
  83
  84 /** The number for a value slot in a document.
  85  *
  86  *  Value slot numbers are unsigned and (currently) a 32-bit quantity, with
  87  *  Xapian::BAD_VALUENO being represented by the largest possible value.
  88  *  Therefore value slots 0 to 0xFFFFFFFE are available for use.
  89  */
  90 typedef unsigned valueno;
  91
  92 /** A signed difference between two value slot numbers.
  93  *
  94  *  This is used by the Xapian classes which are STL containers of values
  95  *  for "difference_type".
  96  */
  97 typedef int valueno_diff; /* FIXME: can overflow. */
  98
  99 /** Reserved value to indicate "no valueno". */
 100 const valueno BAD_VALUENO = 0xffffffff;
 101
 102 /** Revision number of a database.
 103  *
 104  *  For databases which support this, it increases with each commit.
 105  *
 106  *  Experimental - see https://xapian.org/docs/deprecation#experimental-features
 107  */
 108 typedef XAPIAN_REVISION_TYPE rev;
 109
 110 /** The total length of all documents in a database.
 111  *
 112  *  Added in Xapian 1.4.5.
 113  */
 114 typedef XAPIAN_TOTALLENGTH_TYPE totallength;
 115
 116 }
 117
 118 #endif /* XAPIAN_INCLUDED_TYPES_H */