| 1 | /* C++ implementation of a binary search. |
| 2 | |
| 3 | Copyright (C) 2019-2020 Free Software Foundation, Inc. |
| 4 | |
| 5 | This file is part of GDB. |
| 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 3 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, see <http://www.gnu.org/licenses/>. */ |
| 19 | |
| 20 | |
| 21 | #ifndef GDBSUPPORT_GDB_BINARY_SEARCH_H |
| 22 | #define GDBSUPPORT_GDB_BINARY_SEARCH_H |
| 23 | |
| 24 | #include <algorithm> |
| 25 | |
| 26 | namespace gdb { |
| 27 | |
| 28 | /* Implements a binary search using C++ iterators. |
| 29 | This differs from std::binary_search in that it returns an iterator for |
| 30 | the found element and in that the type of EL can be different from the |
| 31 | type of the elements in the container. |
| 32 | |
| 33 | COMP is a C-style comparison function with signature: |
| 34 | int comp(const value_type& a, const T& b); |
| 35 | It should return -1, 0 or 1 if a is less than, equal to, or greater than |
| 36 | b, respectively. |
| 37 | [first, last) must be sorted. |
| 38 | |
| 39 | The return value is an iterator pointing to the found element, or LAST if |
| 40 | no element was found. */ |
| 41 | template<typename It, typename T, typename Comp> |
| 42 | It binary_search (It first, It last, T el, Comp comp) |
| 43 | { |
| 44 | auto lt = [&] (const typename std::iterator_traits<It>::value_type &a, |
| 45 | const T &b) |
| 46 | { return comp (a, b) < 0; }; |
| 47 | |
| 48 | auto lb = std::lower_bound (first, last, el, lt); |
| 49 | if (lb != last) |
| 50 | { |
| 51 | if (comp (*lb, el) == 0) |
| 52 | return lb; |
| 53 | } |
| 54 | return last; |
| 55 | } |
| 56 | |
| 57 | } /* namespace gdb */ |
| 58 | |
| 59 | #endif /* GDBSUPPORT_GDB_BINARY_SEARCH_H */ |