1 //===--- StringSet.h - The LLVM Compiler Driver -----------------*- C++ -*-===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open 6 // Source License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // 10 // StringSet - A set-like wrapper for the StringMap. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #ifndef LLVM_ADT_STRINGSET_H 15 #define LLVM_ADT_STRINGSET_H 16 17 #include "llvm/ADT/StringMap.h" 18 19 namespace llvm { 20 21 /// StringSet - A wrapper for StringMap that provides set-like functionality. 22 template <class AllocatorTy = llvm::MallocAllocator> 23 class StringSet : public llvm::StringMap<char, AllocatorTy> { 24 typedef llvm::StringMap<char, AllocatorTy> base; 25 public: 26 27 /// insert - Insert the specified key into the set. If the key already 28 /// exists in the set, return false and ignore the request, otherwise insert 29 /// it and return true. insert(StringRef Key)30 bool insert(StringRef Key) { 31 // Get or create the map entry for the key; if it doesn't exist the value 32 // type will be default constructed which we use to detect insert. 33 // 34 // We use '+' as the sentinel value in the map. 35 assert(!Key.empty()); 36 StringMapEntry<char> &Entry = this->GetOrCreateValue(Key); 37 if (Entry.getValue() == '+') 38 return false; 39 Entry.setValue('+'); 40 return true; 41 } 42 }; 43 } 44 45 #endif // LLVM_ADT_STRINGSET_H 46