1
0
mirror of https://github.com/RPCS3/llvm-mirror.git synced 2024-11-26 12:43:36 +01:00
llvm-mirror/include/llvm/ADT/StringSet.h
Daniel Dunbar 3835c43762 [ADT] Fix StringSet::insert() to not allocate on every lookup.
- The previous implementation always constructed the StringMap entry, even if
   the key was present in the set.

llvm-svn: 177178
2013-03-15 20:16:59 +00:00

46 lines
1.5 KiB
C++

//===--- StringSet.h - The LLVM Compiler Driver -----------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open
// Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// StringSet - A set-like wrapper for the StringMap.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_ADT_STRINGSET_H
#define LLVM_ADT_STRINGSET_H
#include "llvm/ADT/StringMap.h"
namespace llvm {
/// StringSet - A wrapper for StringMap that provides set-like functionality.
template <class AllocatorTy = llvm::MallocAllocator>
class StringSet : public llvm::StringMap<char, AllocatorTy> {
typedef llvm::StringMap<char, AllocatorTy> base;
public:
/// insert - Insert the specified key into the set. If the key already
/// exists in the set, return false and ignore the request, otherwise insert
/// it and return true.
bool insert(StringRef Key) {
// Get or create the map entry for the key; if it doesn't exist the value
// type will be default constructed which we use to detect insert.
//
// We use '+' as the sentinel value in the map.
assert(!Key.empty());
StringMapEntry<char> &Entry = this->GetOrCreateValue(Key);
if (Entry.getValue() == '+')
return false;
Entry.setValue('+');
return true;
}
};
}
#endif // LLVM_ADT_STRINGSET_H