81 lines
2.5 KiB
C
81 lines
2.5 KiB
C
/* Find near-matches for identifiers.
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Copyright (C) 2015-2016 Free Software Foundation, Inc.
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This file is part of GCC.
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GCC is free software; you can redistribute it and/or modify it under
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the terms of the GNU General Public License as published by the Free
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Software Foundation; either version 3, or (at your option) any later
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version.
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GCC is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or
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FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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for more details.
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You should have received a copy of the GNU General Public License
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along with GCC; see the file COPYING3. If not see
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<http://www.gnu.org/licenses/>. */
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#include "config.h"
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#include "system.h"
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#include "coretypes.h"
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#include "tm.h"
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#include "tree.h"
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#include "spellcheck.h"
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/* Calculate Levenshtein distance between two identifiers. */
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edit_distance_t
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levenshtein_distance (tree ident_s, tree ident_t)
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{
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gcc_assert (TREE_CODE (ident_s) == IDENTIFIER_NODE);
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gcc_assert (TREE_CODE (ident_t) == IDENTIFIER_NODE);
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return levenshtein_distance (IDENTIFIER_POINTER (ident_s),
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IDENTIFIER_LENGTH (ident_s),
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IDENTIFIER_POINTER (ident_t),
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IDENTIFIER_LENGTH (ident_t));
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}
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/* Given TARGET, an identifier, and CANDIDATES, a vec of identifiers,
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determine which element within CANDIDATES has the lowest edit
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distance to TARGET. If there are multiple elements with the
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same minimal distance, the first in the vector wins.
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If more than half of the letters were misspelled, the suggestion is
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likely to be meaningless, so return NULL_TREE for this case. */
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tree
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find_closest_identifier (tree target, const auto_vec<tree> *candidates)
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{
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gcc_assert (TREE_CODE (target) == IDENTIFIER_NODE);
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int i;
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tree identifier;
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tree best_identifier = NULL_TREE;
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edit_distance_t best_distance = MAX_EDIT_DISTANCE;
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FOR_EACH_VEC_ELT (*candidates, i, identifier)
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{
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gcc_assert (TREE_CODE (identifier) == IDENTIFIER_NODE);
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edit_distance_t dist = levenshtein_distance (target, identifier);
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if (dist < best_distance)
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{
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best_distance = dist;
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best_identifier = identifier;
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}
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}
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/* If more than half of the letters were misspelled, the suggestion is
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likely to be meaningless. */
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if (best_identifier)
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{
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unsigned int cutoff = MAX (IDENTIFIER_LENGTH (target),
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IDENTIFIER_LENGTH (best_identifier)) / 2;
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if (best_distance > cutoff)
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return NULL_TREE;
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}
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return best_identifier;
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}
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