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 39 namespace google { 40 namespace 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. 45 template <class Collection> 46 const typename Collection::value_type::second_type& 47 FindWithDefault(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. 60 template <class Collection> 61 const typename Collection::value_type::second_type* 62 FindOrNull(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, assuming that the key exists. 72 // Crash if it does not. 73 // 74 // This is intended as a replacement for operator[] as an rvalue (for reading) 75 // when the key is guaranteed to exist. 76 // 77 // operator[] is discouraged for several reasons: 78 // * It has a side-effect of inserting missing keys 79 // * It is not thread-safe (even when it is not inserting, it can still 80 // choose to resize the underlying storage) 81 // * It invalidates iterators (when it chooses to resize) 82 // * It default constructs a value object even if it doesn't need to 83 // 84 // This version assumes the key is printable, and includes it in the fatal log 85 // message. 86 template <class Collection> 87 const typename Collection::value_type::second_type& 88 FindOrDie(const Collection& collection, 89 const typename Collection::value_type::first_type& key) { 90 typename Collection::const_iterator it = collection.find(key); 91 GOOGLE_CHECK(it != collection.end()) << "Map key not found: " << key; 92 return it->second; 93 } 94 95 // Perform a lookup in a map or hash_map whose values are pointers. 96 // If the key is present a const pointer to the associated value is returned, 97 // otherwise a NULL pointer is returned. 98 // This function does not distinguish between a missing key and a key mapped 99 // to a NULL value. 100 template <class Collection> 101 const typename Collection::value_type::second_type 102 FindPtrOrNull(const Collection& collection, 103 const typename Collection::value_type::first_type& key) { 104 typename Collection::const_iterator it = collection.find(key); 105 if (it == collection.end()) { 106 return 0; 107 } 108 return it->second; 109 } 110 111 // Change the value associated with a particular key in a map or hash_map. 112 // If the key is not present in the map the key and value are inserted, 113 // otherwise the value is updated to be a copy of the value provided. 114 // True indicates that an insert took place, false indicates an update. 115 template <class Collection, class Key, class Value> 116 bool InsertOrUpdate(Collection * const collection, 117 const Key& key, const Value& value) { 118 pair<typename Collection::iterator, bool> ret = 119 collection->insert(typename Collection::value_type(key, value)); 120 if (!ret.second) { 121 // update 122 ret.first->second = value; 123 return false; 124 } 125 return true; 126 } 127 128 // Insert a new key and value into a map or hash_map. 129 // If the key is not present in the map the key and value are 130 // inserted, otherwise nothing happens. True indicates that an insert 131 // took place, false indicates the key was already present. 132 template <class Collection, class Key, class Value> 133 bool InsertIfNotPresent(Collection * const collection, 134 const Key& key, const Value& value) { 135 pair<typename Collection::iterator, bool> ret = 136 collection->insert(typename Collection::value_type(key, value)); 137 return ret.second; 138 } 139 140 } // namespace protobuf 141 } // namespace google 142 143 #endif // GOOGLE_PROTOBUF_STUBS_MAP_UTIL_H__ 144
