1 //===--- MemoryBuffer.h - Memory Buffer Interface ---------------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file defines the MemoryBuffer interface.
12 //===----------------------------------------------------------------------===//
14 #ifndef LLVM_SUPPORT_MEMORYBUFFER_H
15 #define LLVM_SUPPORT_MEMORYBUFFER_H
17 #include "llvm-c/Support.h"
18 #include "llvm/ADT/Twine.h"
19 #include "llvm/Support/CBindingWrapping.h"
20 #include "llvm/Support/DataTypes.h"
21 #include "llvm/Support/ErrorOr.h"
25 class MemoryBufferRef;
27 /// This interface provides simple read-only access to a block of memory, and
28 /// provides simple methods for reading files and standard input into a memory
29 /// buffer. In addition to basic access to the characters in the file, this
30 /// interface guarantees you can read one character past the end of the file,
31 /// and that this character will read as '\0'.
33 /// The '\0' guarantee is needed to support an optimization -- it's intended to
34 /// be more efficient for clients which are reading all the data to stop
35 /// reading when they encounter a '\0' than to continually check the file
36 /// position to see if it has reached the end of the file.
38 const char *BufferStart; // Start of the buffer.
39 const char *BufferEnd; // End of the buffer.
41 MemoryBuffer(const MemoryBuffer &) = delete;
42 MemoryBuffer &operator=(const MemoryBuffer &) = delete;
45 void init(const char *BufStart, const char *BufEnd,
46 bool RequiresNullTerminator);
48 virtual ~MemoryBuffer();
50 const char *getBufferStart() const { return BufferStart; }
51 const char *getBufferEnd() const { return BufferEnd; }
52 size_t getBufferSize() const { return BufferEnd-BufferStart; }
54 StringRef getBuffer() const {
55 return StringRef(BufferStart, getBufferSize());
58 /// Return an identifier for this buffer, typically the filename it was read
60 virtual const char *getBufferIdentifier() const {
61 return "Unknown buffer";
64 /// Open the specified file as a MemoryBuffer, returning a new MemoryBuffer
65 /// if successful, otherwise returning null. If FileSize is specified, this
66 /// means that the client knows that the file exists and that it has the
69 /// \param IsVolatileSize Set to true to indicate that the file size may be
70 /// changing, e.g. when libclang tries to parse while the user is
71 /// editing/updating the file.
72 static ErrorOr<std::unique_ptr<MemoryBuffer>>
73 getFile(const Twine &Filename, int64_t FileSize = -1,
74 bool RequiresNullTerminator = true, bool IsVolatileSize = false);
76 /// Given an already-open file descriptor, map some slice of it into a
77 /// MemoryBuffer. The slice is specified by an \p Offset and \p MapSize.
78 /// Since this is in the middle of a file, the buffer is not null terminated.
79 static ErrorOr<std::unique_ptr<MemoryBuffer>>
80 getOpenFileSlice(int FD, const Twine &Filename, uint64_t MapSize,
83 /// Given an already-open file descriptor, read the file and return a
86 /// \param IsVolatileSize Set to true to indicate that the file size may be
87 /// changing, e.g. when libclang tries to parse while the user is
88 /// editing/updating the file.
89 static ErrorOr<std::unique_ptr<MemoryBuffer>>
90 getOpenFile(int FD, const Twine &Filename, uint64_t FileSize,
91 bool RequiresNullTerminator = true, bool IsVolatileSize = false);
93 /// Open the specified memory range as a MemoryBuffer. Note that InputData
94 /// must be null terminated if RequiresNullTerminator is true.
95 static std::unique_ptr<MemoryBuffer>
96 getMemBuffer(StringRef InputData, StringRef BufferName = "",
97 bool RequiresNullTerminator = true);
99 static std::unique_ptr<MemoryBuffer>
100 getMemBuffer(MemoryBufferRef Ref, bool RequiresNullTerminator = true);
102 /// Open the specified memory range as a MemoryBuffer, copying the contents
103 /// and taking ownership of it. InputData does not have to be null terminated.
104 static std::unique_ptr<MemoryBuffer>
105 getMemBufferCopy(StringRef InputData, const Twine &BufferName = "");
107 /// Allocate a new zero-initialized MemoryBuffer of the specified size. Note
108 /// that the caller need not initialize the memory allocated by this method.
109 /// The memory is owned by the MemoryBuffer object.
110 static std::unique_ptr<MemoryBuffer>
111 getNewMemBuffer(size_t Size, StringRef BufferName = "");
113 /// Allocate a new MemoryBuffer of the specified size that is not initialized.
114 /// Note that the caller should initialize the memory allocated by this
115 /// method. The memory is owned by the MemoryBuffer object.
116 static std::unique_ptr<MemoryBuffer>
117 getNewUninitMemBuffer(size_t Size, const Twine &BufferName = "");
119 /// Read all of stdin into a file buffer, and return it.
120 static ErrorOr<std::unique_ptr<MemoryBuffer>> getSTDIN();
122 /// Open the specified file as a MemoryBuffer, or open stdin if the Filename
124 static ErrorOr<std::unique_ptr<MemoryBuffer>>
125 getFileOrSTDIN(const Twine &Filename, int64_t FileSize = -1,
126 bool RequiresNullTerminator = true);
128 /// Map a subrange of the specified file as a MemoryBuffer.
129 static ErrorOr<std::unique_ptr<MemoryBuffer>>
130 getFileSlice(const Twine &Filename, uint64_t MapSize, uint64_t Offset);
132 //===--------------------------------------------------------------------===//
133 // Provided for performance analysis.
134 //===--------------------------------------------------------------------===//
136 /// The kind of memory backing used to support the MemoryBuffer.
142 /// Return information on the memory mechanism used to support the
144 virtual BufferKind getBufferKind() const = 0;
146 MemoryBufferRef getMemBufferRef() const;
149 class MemoryBufferRef {
151 StringRef Identifier;
155 MemoryBufferRef(MemoryBuffer& Buffer)
156 : Buffer(Buffer.getBuffer()), Identifier(Buffer.getBufferIdentifier()) {}
157 MemoryBufferRef(StringRef Buffer, StringRef Identifier)
158 : Buffer(Buffer), Identifier(Identifier) {}
160 StringRef getBuffer() const { return Buffer; }
162 StringRef getBufferIdentifier() const { return Identifier; }
164 const char *getBufferStart() const { return Buffer.begin(); }
165 const char *getBufferEnd() const { return Buffer.end(); }
166 size_t getBufferSize() const { return Buffer.size(); }
169 // Create wrappers for C Binding types (see CBindingWrapping.h).
170 DEFINE_SIMPLE_CONVERSION_FUNCTIONS(MemoryBuffer, LLVMMemoryBufferRef)
172 } // end namespace llvm