1// Protocol Buffers - Google's data interchange format 2// Copyright 2008 Google Inc. All rights reserved. 3// http://code.google.com/p/protobuf/ 4// 5// Redistribution and use in source and binary forms, with or without 6// modification, are permitted provided that the following conditions are 7// met: 8// 9// * Redistributions of source code must retain the above copyright 10// notice, this list of conditions and the following disclaimer. 11// * Redistributions in binary form must reproduce the above 12// copyright notice, this list of conditions and the following disclaimer 13// in the documentation and/or other materials provided with the 14// distribution. 15// * Neither the name of Google Inc. nor the names of its 16// contributors may be used to endorse or promote products derived from 17// this software without specific prior written permission. 18// 19// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 20// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 21// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 22// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 23// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 24// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 25// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 26// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 27// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 28// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 29// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 30 31// from google3/util/gtl/map-util.h 32// Author: Anton Carver 33 34#ifndef GOOGLE_PROTOBUF_STUBS_MAP_UTIL_H__ 35#define GOOGLE_PROTOBUF_STUBS_MAP_UTIL_H__ 36 37#include <google/protobuf/stubs/common.h> 38 39namespace google { 40namespace protobuf { 41 42// Perform a lookup in a map or hash_map. 43// If the key is present in the map then the value associated with that 44// key is returned, otherwise the value passed as a default is returned. 45template <class Collection> 46const typename Collection::value_type::second_type& 47FindWithDefault(const Collection& collection, 48 const typename Collection::value_type::first_type& key, 49 const typename Collection::value_type::second_type& value) { 50 typename Collection::const_iterator it = collection.find(key); 51 if (it == collection.end()) { 52 return value; 53 } 54 return it->second; 55} 56 57// Perform a lookup in a map or hash_map. 58// If the key is present a const pointer to the associated value is returned, 59// otherwise a NULL pointer is returned. 60template <class Collection> 61const typename Collection::value_type::second_type* 62FindOrNull(const Collection& collection, 63 const typename Collection::value_type::first_type& key) { 64 typename Collection::const_iterator it = collection.find(key); 65 if (it == collection.end()) { 66 return 0; 67 } 68 return &it->second; 69} 70 71// Perform a lookup in a map or hash_map whose values are pointers. 72// If the key is present a const pointer to the associated value is returned, 73// otherwise a NULL pointer is returned. 74// This function does not distinguish between a missing key and a key mapped 75// to a NULL value. 76template <class Collection> 77const typename Collection::value_type::second_type 78FindPtrOrNull(const Collection& collection, 79 const typename Collection::value_type::first_type& key) { 80 typename Collection::const_iterator it = collection.find(key); 81 if (it == collection.end()) { 82 return 0; 83 } 84 return it->second; 85} 86 87// Change the value associated with a particular key in a map or hash_map. 88// If the key is not present in the map the key and value are inserted, 89// otherwise the value is updated to be a copy of the value provided. 90// True indicates that an insert took place, false indicates an update. 91template <class Collection, class Key, class Value> 92bool InsertOrUpdate(Collection * const collection, 93 const Key& key, const Value& value) { 94 pair<typename Collection::iterator, bool> ret = 95 collection->insert(typename Collection::value_type(key, value)); 96 if (!ret.second) { 97 // update 98 ret.first->second = value; 99 return false; 100 } 101 return true; 102} 103 104// Insert a new key and value into a map or hash_map. 105// If the key is not present in the map the key and value are 106// inserted, otherwise nothing happens. True indicates that an insert 107// took place, false indicates the key was already present. 108template <class Collection, class Key, class Value> 109bool InsertIfNotPresent(Collection * const collection, 110 const Key& key, const Value& value) { 111 pair<typename Collection::iterator, bool> ret = 112 collection->insert(typename Collection::value_type(key, value)); 113 return ret.second; 114} 115 116} // namespace protobuf 117} // namespace google 118 119#endif // GOOGLE_PROTOBUF_STUBS_MAP_UTIL_H__ 120