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comparison include/llvm/Support/MemoryBuffer.h @ 0:95c75e76d11b LLVM3.4

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LLVM 3.4
author Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
date Thu, 12 Dec 2013 13:56:28 +0900
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children 54457678186b
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-1:000000000000 0:95c75e76d11b
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/Twine.h"
18 #include "llvm/Support/CBindingWrapping.h"
19 #include "llvm/Support/Compiler.h"
20 #include "llvm/Support/DataTypes.h"
21 #include "llvm-c/Core.h"
22
23 namespace llvm {
24
25 class error_code;
26 template<class T> class OwningPtr;
27
28 /// MemoryBuffer - This interface provides simple read-only access to a block
29 /// of memory, and provides simple methods for reading files and standard input
30 /// into a memory buffer. In addition to basic access to the characters in the
31 /// file, this interface guarantees you can read one character past the end of
32 /// the file, and that this character will read as '\0'.
33 ///
34 /// The '\0' guarantee is needed to support an optimization -- it's intended to
35 /// be more efficient for clients which are reading all the data to stop
36 /// reading when they encounter a '\0' than to continually check the file
37 /// position to see if it has reached the end of the file.
38 class MemoryBuffer {
39 const char *BufferStart; // Start of the buffer.
40 const char *BufferEnd; // End of the buffer.
41
42 MemoryBuffer(const MemoryBuffer &) LLVM_DELETED_FUNCTION;
43 MemoryBuffer &operator=(const MemoryBuffer &) LLVM_DELETED_FUNCTION;
44 protected:
45 MemoryBuffer() {}
46 void init(const char *BufStart, const char *BufEnd,
47 bool RequiresNullTerminator);
48 public:
49 virtual ~MemoryBuffer();
50
51 const char *getBufferStart() const { return BufferStart; }
52 const char *getBufferEnd() const { return BufferEnd; }
53 size_t getBufferSize() const { return BufferEnd-BufferStart; }
54
55 StringRef getBuffer() const {
56 return StringRef(BufferStart, getBufferSize());
57 }
58
59 /// getBufferIdentifier - Return an identifier for this buffer, typically the
60 /// filename it was read from.
61 virtual const char *getBufferIdentifier() const {
62 return "Unknown buffer";
63 }
64
65 /// getFile - Open the specified file as a MemoryBuffer, returning a new
66 /// MemoryBuffer if successful, otherwise returning null. If FileSize is
67 /// specified, this means that the client knows that the file exists and that
68 /// it has the specified size.
69 static error_code getFile(Twine Filename, OwningPtr<MemoryBuffer> &result,
70 int64_t FileSize = -1,
71 bool RequiresNullTerminator = true);
72
73 /// Given an already-open file descriptor, map some slice of it into a
74 /// MemoryBuffer. The slice is specified by an \p Offset and \p MapSize.
75 /// Since this is in the middle of a file, the buffer is not null terminated.
76 static error_code getOpenFileSlice(int FD, const char *Filename,
77 OwningPtr<MemoryBuffer> &Result,
78 uint64_t MapSize, int64_t Offset);
79
80 /// Given an already-open file descriptor, read the file and return a
81 /// MemoryBuffer.
82 static error_code getOpenFile(int FD, const char *Filename,
83 OwningPtr<MemoryBuffer> &Result,
84 uint64_t FileSize,
85 bool RequiresNullTerminator = true);
86
87 /// getMemBuffer - Open the specified memory range as a MemoryBuffer. Note
88 /// that InputData must be null terminated if RequiresNullTerminator is true.
89 static MemoryBuffer *getMemBuffer(StringRef InputData,
90 StringRef BufferName = "",
91 bool RequiresNullTerminator = true);
92
93 /// getMemBufferCopy - Open the specified memory range as a MemoryBuffer,
94 /// copying the contents and taking ownership of it. InputData does not
95 /// have to be null terminated.
96 static MemoryBuffer *getMemBufferCopy(StringRef InputData,
97 StringRef BufferName = "");
98
99 /// getNewMemBuffer - Allocate a new MemoryBuffer of the specified size that
100 /// is completely initialized to zeros. Note that the caller should
101 /// initialize the memory allocated by this method. The memory is owned by
102 /// the MemoryBuffer object.
103 static MemoryBuffer *getNewMemBuffer(size_t Size, StringRef BufferName = "");
104
105 /// getNewUninitMemBuffer - Allocate a new MemoryBuffer of the specified size
106 /// that is not initialized. Note that the caller should initialize the
107 /// memory allocated by this method. The memory is owned by the MemoryBuffer
108 /// object.
109 static MemoryBuffer *getNewUninitMemBuffer(size_t Size,
110 StringRef BufferName = "");
111
112 /// getSTDIN - Read all of stdin into a file buffer, and return it.
113 /// If an error occurs, this returns null and sets ec.
114 static error_code getSTDIN(OwningPtr<MemoryBuffer> &result);
115
116
117 /// getFileOrSTDIN - Open the specified file as a MemoryBuffer, or open stdin
118 /// if the Filename is "-". If an error occurs, this returns null and sets
119 /// ec.
120 static error_code getFileOrSTDIN(StringRef Filename,
121 OwningPtr<MemoryBuffer> &result,
122 int64_t FileSize = -1);
123
124 //===--------------------------------------------------------------------===//
125 // Provided for performance analysis.
126 //===--------------------------------------------------------------------===//
127
128 /// The kind of memory backing used to support the MemoryBuffer.
129 enum BufferKind {
130 MemoryBuffer_Malloc,
131 MemoryBuffer_MMap
132 };
133
134 /// Return information on the memory mechanism used to support the
135 /// MemoryBuffer.
136 virtual BufferKind getBufferKind() const = 0;
137 };
138
139 // Create wrappers for C Binding types (see CBindingWrapping.h).
140 DEFINE_SIMPLE_CONVERSION_FUNCTIONS(MemoryBuffer, LLVMMemoryBufferRef)
141
142 } // end namespace llvm
143
144 #endif