+++ /dev/null
-//===-- UsuallyTinyPtrVector.h - Pointer vector class -----------*- 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 UsuallyTinyPtrVector class, which is a vector that
-// optimizes the case where there is only one element.
-//
-//===----------------------------------------------------------------------===//
-
-#ifndef LLVM_ADT_USUALLY_TINY_PTR_VECTOR_H
-#define LLVM_ADT_USUALLY_TINY_PTR_VECTOR_H
-
-#include <vector>
-
-namespace llvm {
-
-/// \brief A vector class template that is optimized for storing a single
-/// pointer element.
-template<typename T>
-class UsuallyTinyPtrVector {
- /// \brief Storage for the vector.
- ///
- /// When the low bit is zero, this is a T *. When the
- /// low bit is one, this is a std::vector<T *> *.
- mutable uintptr_t Storage;
-
- typedef std::vector<T*> vector_type;
-
-public:
- UsuallyTinyPtrVector() : Storage(0) { }
- explicit UsuallyTinyPtrVector(T *Element)
- : Storage(reinterpret_cast<uintptr_t>(Element)) { }
-
- bool empty() const { return !Storage; }
-
- typedef const T **iterator;
- iterator begin() const;
- iterator end() const;
- size_t size() const;
-
- void push_back(T *Method);
- iterator erase(const iterator ElementPos);
- void Destroy();
-};
-
-template<typename T>
-typename UsuallyTinyPtrVector<T>::iterator
-UsuallyTinyPtrVector<T>::begin() const {
- if ((Storage & 0x01) == 0)
- return reinterpret_cast<iterator>(&Storage);
-
- vector_type *Vec = reinterpret_cast<vector_type *>(Storage & ~0x01);
- return &Vec->front();
-}
-
-template<typename T>
-typename UsuallyTinyPtrVector<T>::iterator
-UsuallyTinyPtrVector<T>::end() const {
- if ((Storage & 0x01) == 0) {
- if (Storage == 0)
- return reinterpret_cast<iterator>(&Storage);
-
- return reinterpret_cast<iterator>(&Storage) + 1;
- }
-
- vector_type *Vec = reinterpret_cast<vector_type *>(Storage & ~0x01);
- return &Vec->front() + Vec->size();
-}
-
-template<typename T>
-size_t UsuallyTinyPtrVector<T>::size() const {
- if ((Storage & 0x01) == 0)
- return (Storage == 0) ? 0 : 1;
-
- vector_type *Vec = reinterpret_cast<vector_type *>(Storage & ~0x01);
- return Vec->size();
-}
-
-template<typename T>
-void UsuallyTinyPtrVector<T>::push_back(T *Element) {
- if (Storage == 0) {
- // 0 -> 1 element.
- Storage = reinterpret_cast<uintptr_t>(Element);
- return;
- }
-
- vector_type *Vec;
- if ((Storage & 0x01) == 0) {
- // 1 -> 2 elements. Allocate a new vector and push the element into that
- // vector.
- Vec = new vector_type;
- Vec->push_back(reinterpret_cast<T *>(Storage));
- Storage = reinterpret_cast<uintptr_t>(Vec) | 0x01;
- } else
- Vec = reinterpret_cast<vector_type *>(Storage & ~0x01);
-
- // Add the new element to the vector.
- Vec->push_back(Element);
-}
-
-template<typename T>
-typename UsuallyTinyPtrVector<T>::iterator
-UsuallyTinyPtrVector<T>::erase(
- const typename UsuallyTinyPtrVector<T>::iterator ElementPos) {
- // only one item
- if ((Storage & 0x01) == 0) {
- // if the element is found remove it
- if (ElementPos == reinterpret_cast<T **>(&Storage))
- Storage = 0;
- } else {
- // multiple items in a vector; just do the erase, there is no
- // benefit to collapsing back to a pointer
- vector_type *Vec = reinterpret_cast<vector_type *>(Storage & ~0x01);
- unsigned index = ElementPos -
- const_cast<typename UsuallyTinyPtrVector<T>::iterator>(&Vec->front());
- if (index < Vec->size())
- return const_cast<typename UsuallyTinyPtrVector<T>::iterator>(
- &*(Vec->erase(Vec->begin() + index)));
- }
- return end();
-}
-
-template<typename T>
-void UsuallyTinyPtrVector<T>::Destroy() {
- if (Storage & 0x01)
- delete reinterpret_cast<vector_type *>(Storage & ~0x01);
-
- Storage = 0;
-}
-
-}
-#endif