//===- llvm/ADT/PointerIntPair.h - Pair for pointer and int -----*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines the PointerIntPair class.
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_ADT_POINTERINTPAIR_H
#define LLVM_ADT_POINTERINTPAIR_H

#include <cassert>

namespace llvm {
  
/// PointerIntPair - This class implements a pair of a pointer and small
/// integer.  It is designed to represet this in the space required by one
/// pointer by bitmangling the integer into the low part of the pointer.  This
/// can only be done for small integers: typically up to 3 bits, but it depends
/// on the alignment returned by the allocator in use.
///
template <typename PointerTy, unsigned IntBits, typename IntType=unsigned>
class PointerIntPair {
  intptr_t Value;
public:
  PointerIntPair() : Value(0) {}
  PointerIntPair(PointerTy Ptr, IntType Int) : Value(0) {
    setPointer(Ptr);
    setInt(Int);
  }

  PointerTy getPointer() const {
    return reinterpret_cast<PointerTy>(Value & ~((1 << IntBits)-1));
  }
  
  IntType getInt() const {
    return (IntType)(Value & (1 << IntBits)-1);
  }
  
  void setPointer(PointerTy Ptr) {
    intptr_t PtrVal = reinterpret_cast<intptr_t>(Ptr);
    assert((PtrVal & (1 << IntBits)-1) == 0 &&
           "Pointer is no sufficiently aligned");
    Value = PtrVal | (intptr_t)getInt();
  }
  
  void setInt(IntType Int) {
    assert(Int < (1 << IntBits) && "Integer too large for field");
    Value |= reinterpret_cast<intptr_t>(getPointer()) | (intptr_t)Int;
  }
  
  void *getOpaqueValue() const { return reinterpret_cast<void*>(Value); }
  void setFromOpaqueValue(void *Val) { Value = reinterpret_cast<intptr_t>(Val);}
  
  bool operator==(const PointerIntPair &RHS) const {
    return Value == RHS.Value;
  }
  bool operator!=(const PointerIntPair &RHS) const {
    return Value != RHS.Value;
  }
};

} // end namespace llvm
#endif