xapian-core/backends/glass/glass_spellingwordslist.cc

   1 /** @file glass_spellingwordslist.cc
   2  * @brief Iterator for the spelling correction words in a glass database.
   3  */
   4 /* Copyright (C) 2004,2005,2006,2007,2008,2009,2017 Olly Betts
   5  * Copyright (C) 2007 Lemur Consulting Ltd
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
  20  */
  21
  22 #include <config.h>
  23
  24 #include "glass_spellingwordslist.h"
  25
  26 #include "xapian/error.h"
  27 #include "xapian/types.h"
  28
  29 #include "debuglog.h"
  30 #include "glass_database.h"
  31 #include "pack.h"
  32 #include "stringutils.h"
  33
  34 GlassSpellingWordsList::~GlassSpellingWordsList()
  35 {
  36     LOGCALL_DTOR(DB, "GlassSpellingWordsList");
  37     delete cursor;
  38 }
  39
  40 Xapian::termcount
  41 GlassSpellingWordsList::get_approx_size() const
  42 {
  43     // This is an over-estimate, but we only use this value to build a balanced
  44     // or-tree, and it'll do a decent enough job for that.
  45     return database->spelling_table.get_entry_count();
  46 }
  47
  48 string
  49 GlassSpellingWordsList::get_termname() const
  50 {
  51     LOGCALL(DB, string, "GlassSpellingWordsList::get_termname", NO_ARGS);
  52     Assert(cursor);
  53     Assert(!at_end());
  54     Assert(!cursor->current_key.empty());
  55     Assert(cursor->current_key[0] == 'W');
  56     RETURN(cursor->current_key.substr(1));
  57 }
  58
  59 Xapian::doccount
  60 GlassSpellingWordsList::get_termfreq() const
  61 {
  62     LOGCALL(DB, Xapian::doccount, "GlassSpellingWordsList::get_termfreq", NO_ARGS);
  63     Assert(cursor);
  64     Assert(!at_end());
  65     Assert(!cursor->current_key.empty());
  66     Assert(cursor->current_key[0] == 'W');
  67     cursor->read_tag();
  68
  69     Xapian::termcount freq;
  70     const char *p = cursor->current_tag.data();
  71     if (!unpack_uint_last(&p, p + cursor->current_tag.size(), &freq)) {
  72         throw Xapian::DatabaseCorruptError("Bad spelling word freq");
  73     }
  74     RETURN(freq);
  75 }
  76
  77 Xapian::termcount
  78 GlassSpellingWordsList::get_collection_freq() const
  79 {
  80     throw Xapian::InvalidOperationError("GlassSpellingWordsList::get_collection_freq() not meaningful");
  81 }
  82
  83 TermList *
  84 GlassSpellingWordsList::next()
  85 {
  86     LOGCALL(DB, TermList *, "GlassSpellingWordsList::next", NO_ARGS);
  87     Assert(!at_end());
  88
  89     cursor->next();
  90     if (!cursor->after_end() && !startswith(cursor->current_key, 'W')) {
  91         // We've reached the end of the prefixed terms.
  92         cursor->to_end();
  93     }
  94
  95     RETURN(NULL);
  96 }
  97
  98 TermList *
  99 GlassSpellingWordsList::skip_to(const string &tname)
 100 {
 101     LOGCALL(DB, TermList *, "GlassSpellingWordsList::skip_to", tname);
 102     Assert(!at_end());
 103
 104     if (!cursor->find_entry_ge("W" + tname)) {
 105         // The exact term we asked for isn't there, so check if the next
 106         // term after it also has a W prefix.
 107         if (!cursor->after_end() && !startswith(cursor->current_key, 'W')) {
 108             // We've reached the end of the prefixed terms.
 109             cursor->to_end();
 110         }
 111     }
 112     RETURN(NULL);
 113 }
 114
 115 bool
 116 GlassSpellingWordsList::at_end() const
 117 {
 118     LOGCALL(DB, bool, "GlassSpellingWordsList::at_end", NO_ARGS);
 119     RETURN(cursor->after_end());
 120 }