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llvm-mirror/include/llvm/ADT/IndexedMap.h
Andrew Trick 56264ae675 SparseSet: Add support for key-derived indexes and arbitrary key types.
This nicely handles the most common case of virtual register sets, but
also handles anticipated cases where we will map pointers to IDs.

The goal is not to develop a completely generic SparseSet
template. Instead we want to handle the expected uses within llvm
without any template antics in the client code. I'm adding a bit of
template nastiness here, and some assumption about expected usage in
order to make the client code very clean.

The expected common uses cases I'm designing for:
- integer keys that need to be reindexed, and may map to additional
  data
- densely numbered objects where we want pointer keys because no
  number->object map exists.

llvm-svn: 155227
2012-04-20 20:05:28 +00:00

83 lines
2.3 KiB
C++

//===- llvm/ADT/IndexedMap.h - An index map implementation ------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements an indexed map. The index map template takes two
// types. The first is the mapped type and the second is a functor
// that maps its argument to a size_t. On instantiation a "null" value
// can be provided to be used as a "does not exist" indicator in the
// map. A member function grow() is provided that given the value of
// the maximally indexed key (the argument of the functor) makes sure
// the map has enough space for it.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_ADT_INDEXEDMAP_H
#define LLVM_ADT_INDEXEDMAP_H
#include "llvm/ADT/STLExtras.h"
#include <cassert>
#include <functional>
#include <vector>
namespace llvm {
template <typename T, typename ToIndexT = llvm::identity<unsigned> >
class IndexedMap {
typedef typename ToIndexT::argument_type IndexT;
typedef std::vector<T> StorageT;
StorageT storage_;
T nullVal_;
ToIndexT toIndex_;
public:
IndexedMap() : nullVal_(T()) { }
explicit IndexedMap(const T& val) : nullVal_(val) { }
typename StorageT::reference operator[](IndexT n) {
assert(toIndex_(n) < storage_.size() && "index out of bounds!");
return storage_[toIndex_(n)];
}
typename StorageT::const_reference operator[](IndexT n) const {
assert(toIndex_(n) < storage_.size() && "index out of bounds!");
return storage_[toIndex_(n)];
}
void reserve(typename StorageT::size_type s) {
storage_.reserve(s);
}
void resize(typename StorageT::size_type s) {
storage_.resize(s, nullVal_);
}
void clear() {
storage_.clear();
}
void grow(IndexT n) {
unsigned NewSize = toIndex_(n) + 1;
if (NewSize > storage_.size())
resize(NewSize);
}
bool inBounds(IndexT n) const {
return toIndex_(n) < storage_.size();
}
typename StorageT::size_type size() const {
return storage_.size();
}
};
} // End llvm namespace
#endif