MemoryBuffer.h revision 4c842dda3939c6b9f83ba7e8e19e43445cd9a832 
1//===--- MemoryBuffer.h - Memory Buffer Interface ---------------*- C++ -*-===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10//  This file defines the MemoryBuffer interface.
11//
12//===----------------------------------------------------------------------===//
13
14#ifndef LLVM_SUPPORT_MEMORYBUFFER_H
15#define LLVM_SUPPORT_MEMORYBUFFER_H
16
17#include "llvm/ADT/StringRef.h"
18#include "llvm/System/DataTypes.h"
19#include <string>
20#include <sys/stat.h>
21
22namespace llvm {
23
24/// MemoryBuffer - This interface provides simple read-only access to a block
25/// of memory, and provides simple methods for reading files and standard input
26/// into a memory buffer.  In addition to basic access to the characters in the
27/// file, this interface guarantees you can read one character past the end of
28/// the file, and that this character will read as '\0'.
29class MemoryBuffer {
30  const char *BufferStart; // Start of the buffer.
31  const char *BufferEnd;   // End of the buffer.
32
33  /// MustDeleteBuffer - True if we allocated this buffer.  If so, the
34  /// destructor must know the delete[] it.
35  bool MustDeleteBuffer;
36protected:
37  MemoryBuffer() : MustDeleteBuffer(false) {}
38  void init(const char *BufStart, const char *BufEnd);
39  void initCopyOf(const char *BufStart, const char *BufEnd);
40public:
41  virtual ~MemoryBuffer();
42
43  const char *getBufferStart() const { return BufferStart; }
44  const char *getBufferEnd() const   { return BufferEnd; }
45  size_t getBufferSize() const { return BufferEnd-BufferStart; }
46
47  StringRef getBuffer() const {
48    return StringRef(BufferStart, getBufferSize());
49  }
50
51  /// getBufferIdentifier - Return an identifier for this buffer, typically the
52  /// filename it was read from.
53  virtual const char *getBufferIdentifier() const {
54    return "Unknown buffer";
55  }
56
57  /// getFile - Open the specified file as a MemoryBuffer, returning a new
58  /// MemoryBuffer if successful, otherwise returning null.  If FileSize is
59  /// specified, this means that the client knows that the file exists and that
60  /// it has the specified size.
61  static MemoryBuffer *getFile(StringRef Filename,
62                               std::string *ErrStr = 0,
63                               int64_t FileSize = -1,
64                               struct stat *FileInfo = 0);
65
66  /// getMemBuffer - Open the specified memory range as a MemoryBuffer.  Note
67  /// that EndPtr[0] must be a null byte and be accessible!
68  static MemoryBuffer *getMemBuffer(StringRef InputData,
69                                    const char *BufferName = "");
70
71  /// getMemBufferCopy - Open the specified memory range as a MemoryBuffer,
72  /// copying the contents and taking ownership of it.  This has no requirements
73  /// on EndPtr[0].
74  static MemoryBuffer *getMemBufferCopy(StringRef InputData,
75                                        const char *BufferName = "");
76
77  /// getNewMemBuffer - Allocate a new MemoryBuffer of the specified size that
78  /// is completely initialized to zeros.  Note that the caller should
79  /// initialize the memory allocated by this method.  The memory is owned by
80  /// the MemoryBuffer object.
81  static MemoryBuffer *getNewMemBuffer(size_t Size,
82                                       const char *BufferName = "");
83
84  /// getNewUninitMemBuffer - Allocate a new MemoryBuffer of the specified size
85  /// that is not initialized.  Note that the caller should initialize the
86  /// memory allocated by this method.  The memory is owned by the MemoryBuffer
87  /// object.
88  static MemoryBuffer *getNewUninitMemBuffer(size_t Size,
89                                             StringRef BufferName = "");
90
91  /// getSTDIN - Read all of stdin into a file buffer, and return it.
92  static MemoryBuffer *getSTDIN();
93
94
95  /// getFileOrSTDIN - Open the specified file as a MemoryBuffer, or open stdin
96  /// if the Filename is "-".  If an error occurs, this returns null and fills
97  /// in *ErrStr with a reason.
98  static MemoryBuffer *getFileOrSTDIN(StringRef Filename,
99                                      std::string *ErrStr = 0,
100                                      int64_t FileSize = -1,
101                                      struct stat *FileInfo = 0);
102};
103
104} // end namespace llvm
105
106#endif
107