FragmentRef.h revision 37b74a387bb3993387029859c2d9d051c41c724e 
1//===- FragmentRef.h ------------------------------------------------------===//
2//
3//                     The MCLinker Project
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9#ifndef MCLD_FRAGMENT_FRAGMENTREF_H_
10#define MCLD_FRAGMENT_FRAGMENTREF_H_
11
12#include "mcld/ADT/SizeTraits.h"
13#include "mcld/ADT/TypeTraits.h"
14#include "mcld/Config/Config.h"
15#include "mcld/Support/Allocators.h"
16
17namespace mcld {
18
19class Fragment;
20class LDSection;
21class Layout;
22
23/** \class FragmentRef
24 *  \brief FragmentRef is a reference of a Fragment's contetnt.
25 *
26 */
27class FragmentRef {
28 public:
29  typedef uint64_t Offset;  // FIXME: use SizeTraits<T>::Offset
30  typedef NonConstTraits<unsigned char>::pointer Address;
31  typedef ConstTraits<unsigned char>::pointer ConstAddress;
32
33 public:
34  /// Create - create a fragment reference for a given fragment.
35  ///
36  /// @param pFrag - the given fragment
37  /// @param pOffset - the offset, can be larger than the fragment, but can not
38  ///                  be larger than the section size.
39  /// @return if the offset is legal, return the fragment reference. Otherwise,
40  /// return NULL.
41  static FragmentRef* Create(Fragment& pFrag, uint64_t pOffset);
42
43  static FragmentRef* Create(LDSection& pSection, uint64_t pOffset);
44
45  /// Clear - clear all generated FragmentRef in the system.
46  static void Clear();
47
48  static FragmentRef* Null();
49
50  // -----  modifiers  ----- //
51  FragmentRef& assign(const FragmentRef& pCopy);
52
53  FragmentRef& assign(Fragment& pFrag, Offset pOffset = 0);
54
55  /// memcpy - copy memory
56  /// copy memory from the fragment to the pDesc.
57  /// @pDest - the destination address
58  /// @pNBytes - copies pNBytes from the fragment[offset()+pOffset]
59  /// @pOffset - additional offset.
60  ///            the start address offset from fragment[offset()]
61  void memcpy(void* pDest, size_t pNBytes, Offset pOffset = 0) const;
62
63  // -----  observers  ----- //
64  bool isNull() const { return (this == Null()); }
65
66  Fragment* frag() { return m_pFragment; }
67
68  const Fragment* frag() const { return m_pFragment; }
69
70  Offset offset() const { return m_Offset; }
71
72  Offset getOutputOffset() const;
73
74 private:
75  friend FragmentRef& NullFragmentRef();
76  friend class Chunk<FragmentRef, MCLD_SECTIONS_PER_INPUT>;
77  friend class Relocation;
78
79  FragmentRef();
80
81  explicit FragmentRef(Fragment& pFrag, Offset pOffset = 0);
82
83 private:
84  Fragment* m_pFragment;
85
86  Offset m_Offset;
87
88  static FragmentRef g_NullFragmentRef;
89};
90
91}  // namespace mcld
92
93#endif  // MCLD_FRAGMENT_FRAGMENTREF_H_
94