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