llvm-6502/include/llvm/ADT/TinyPtrVector.h

143 lines
3.7 KiB
C
Raw Normal View History

//===- llvm/ADT/TinyPtrVector.h - 'Normally tiny' vectors -------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_ADT_TINYPTRVECTOR_H
#define LLVM_ADT_TINYPTRVECTOR_H
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/PointerUnion.h"
namespace llvm {
/// TinyPtrVector - This class is specialized for cases where there are
/// normally 0 or 1 element in a vector, but is general enough to go beyond that
/// when required.
///
/// NOTE: This container doesn't allow you to store a null pointer into it.
///
template <typename EltTy>
class TinyPtrVector {
public:
typedef llvm::SmallVector<EltTy, 4> VecTy;
llvm::PointerUnion<EltTy, VecTy*> Val;
TinyPtrVector() {}
TinyPtrVector(const TinyPtrVector &RHS) : Val(RHS.Val) {
if (VecTy *V = Val.template dyn_cast<VecTy*>())
Val = new VecTy(*V);
}
~TinyPtrVector() {
if (VecTy *V = Val.template dyn_cast<VecTy*>())
delete V;
}
// implicit conversion operator to ArrayRef.
operator ArrayRef<EltTy>() const {
if (Val.isNull())
return ArrayRef<EltTy>();
if (Val.template is<EltTy>())
return *Val.template getAddrOf<EltTy>();
return *Val.template get<VecTy*>();
}
bool empty() const {
// This vector can be empty if it contains no element, or if it
// contains a pointer to an empty vector.
if (Val.isNull()) return true;
if (VecTy *Vec = Val.template dyn_cast<VecTy*>())
return Vec->empty();
return false;
}
unsigned size() const {
if (empty())
return 0;
if (Val.template is<EltTy>())
return 1;
return Val.template get<VecTy*>()->size();
}
typedef const EltTy *iterator;
iterator begin() const {
if (empty())
return 0;
if (Val.template is<EltTy>())
return Val.template getAddrOf<EltTy>();
return Val.template get<VecTy *>()->begin();
}
iterator end() const {
if (empty())
return 0;
if (Val.template is<EltTy>())
return begin() + 1;
return Val.template get<VecTy *>()->end();
}
EltTy operator[](unsigned i) const {
assert(!Val.isNull() && "can't index into an empty vector");
if (EltTy V = Val.template dyn_cast<EltTy>()) {
assert(i == 0 && "tinyvector index out of range");
return V;
}
assert(i < Val.template get<VecTy*>()->size() &&
"tinyvector index out of range");
return (*Val.template get<VecTy*>())[i];
}
EltTy front() const {
assert(!empty() && "vector empty");
if (EltTy V = Val.template dyn_cast<EltTy>())
return V;
return Val.template get<VecTy*>()->front();
}
void push_back(EltTy NewVal) {
assert(NewVal != 0 && "Can't add a null value");
// If we have nothing, add something.
if (Val.isNull()) {
Val = NewVal;
return;
}
// If we have a single value, convert to a vector.
if (EltTy V = Val.template dyn_cast<EltTy>()) {
Val = new VecTy();
Val.template get<VecTy*>()->push_back(V);
}
// Add the new value, we know we have a vector.
Val.template get<VecTy*>()->push_back(NewVal);
}
void clear() {
// If we have a single value, convert to empty.
if (Val.template is<EltTy>()) {
Val = (EltTy)0;
} else if (VecTy *Vec = Val.template dyn_cast<VecTy*>()) {
// If we have a vector form, just clear it.
Vec->clear();
}
// Otherwise, we're already empty.
}
private:
void operator=(const TinyPtrVector&); // NOT IMPLEMENTED YET.
};
} // end namespace llvm
#endif