00001 /* vim: set sw=4 sts=4 et foldmethod=syntax : */ 00002 00003 /* 00004 * Copyright (c) 2007, 2008, 2009 Ciaran McCreesh 00005 * Copyright (c) 2007 David Leverton 00006 * 00007 * This file is part of the Paludis package manager. Paludis is free software; 00008 * you can redistribute it and/or modify it under the terms of the GNU General 00009 * Public License version 2, as published by the Free Software Foundation. 00010 * 00011 * Paludis is distributed in the hope that it will be useful, but WITHOUT ANY 00012 * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS 00013 * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more 00014 * details. 00015 * 00016 * You should have received a copy of the GNU General Public License along with 00017 * this program; if not, write to the Free Software Foundation, Inc., 59 Temple 00018 * Place, Suite 330, Boston, MA 02111-1307 USA 00019 */ 00020 00021 #ifndef PALUDIS_GUARD_PALUDIS_UTIL_ITERATOR_FUNCS_HH 00022 #define PALUDIS_GUARD_PALUDIS_UTIL_ITERATOR_FUNCS_HH 1 00023 00024 #include <iterator> 00025 00026 namespace paludis 00027 { 00028 #ifdef PALUDIS_HAVE_STD_NEXT 00029 using std::next; 00030 #else 00031 /** 00032 * Return a new iterator pointing to the item after i. 00033 * 00034 * \ingroup g_iterator 00035 */ 00036 template <typename T_> 00037 T_ next(const T_ & i) 00038 { 00039 T_ result(i); 00040 return ++result; 00041 } 00042 00043 /** 00044 * Return a new iterator advanced by a distance of n. 00045 * 00046 * \ingroup g_iterator 00047 */ 00048 template <typename T_> 00049 T_ next(const T_ & i, const int & n) 00050 { 00051 T_ result(i); 00052 std::advance(result, n); 00053 return result; 00054 } 00055 #endif 00056 00057 /** 00058 * Return a new iterator pointing to the item before i. 00059 * 00060 * \ingroup g_iterator 00061 */ 00062 template <typename T_> 00063 T_ previous(const T_ & i) 00064 { 00065 T_ result(i); 00066 return --result; 00067 } 00068 00069 /** 00070 * Return the distance from a to b, except if it is greater than n, 00071 * in which case return n instead. 00072 * 00073 * \ingroup g_iterator 00074 */ 00075 template <typename T_> 00076 std::size_t capped_distance(T_ a, const T_ & b, unsigned n) 00077 { 00078 std::size_t x(0); 00079 while ((x < n) && (a != b)) 00080 { 00081 ++x; 00082 ++a; 00083 } 00084 return x; 00085 } 00086 } 00087 00088 #endif