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/Support/DataTypes.h" 19 20 namespace llvm { 21 22 class error_code; 23 template<class T> class OwningPtr; 24 25 /// MemoryBuffer - This interface provides simple read-only access to a block 26 /// of memory, and provides simple methods for reading files and standard input 27 /// into a memory buffer. In addition to basic access to the characters in the 28 /// file, this interface guarantees you can read one character past the end of 29 /// the file, and that this character will read as '\0'. 30 /// 31 /// The '\0' guarantee is needed to support an optimization -- it's intended to 32 /// be more efficient for clients which are reading all the data to stop 33 /// reading when they encounter a '\0' than to continually check the file 34 /// position to see if it has reached the end of the file. 35 class MemoryBuffer { 36 const char *BufferStart; // Start of the buffer. 37 const char *BufferEnd; // End of the buffer. 38 39 MemoryBuffer(const MemoryBuffer &); // DO NOT IMPLEMENT 40 MemoryBuffer &operator=(const MemoryBuffer &); // DO NOT IMPLEMENT 41 protected: 42 MemoryBuffer() {} 43 void init(const char *BufStart, const char *BufEnd, 44 bool RequiresNullTerminator); 45 public: 46 virtual ~MemoryBuffer(); 47 48 const char *getBufferStart() const { return BufferStart; } 49 const char *getBufferEnd() const { return BufferEnd; } 50 size_t getBufferSize() const { return BufferEnd-BufferStart; } 51 52 StringRef getBuffer() const { 53 return StringRef(BufferStart, getBufferSize()); 54 } 55 56 /// getBufferIdentifier - Return an identifier for this buffer, typically the 57 /// filename it was read from. 58 virtual const char *getBufferIdentifier() const { 59 return "Unknown buffer"; 60 } 61 62 /// getFile - Open the specified file as a MemoryBuffer, returning a new 63 /// MemoryBuffer if successful, otherwise returning null. If FileSize is 64 /// specified, this means that the client knows that the file exists and that 65 /// it has the specified size. 66 static error_code getFile(StringRef Filename, OwningPtr<MemoryBuffer> &result, 67 int64_t FileSize = -1, 68 bool RequiresNullTerminator = true); 69 static error_code getFile(const char *Filename, 70 OwningPtr<MemoryBuffer> &result, 71 int64_t FileSize = -1, 72 bool RequiresNullTerminator = true); 73 74 /// getOpenFile - Given an already-open file descriptor, read the file and 75 /// return a MemoryBuffer. 76 static error_code getOpenFile(int FD, const char *Filename, 77 OwningPtr<MemoryBuffer> &result, 78 size_t FileSize = -1, 79 size_t MapSize = -1, 80 off_t Offset = 0, 81 bool RequiresNullTerminator = true); 82 83 /// getMemBuffer - Open the specified memory range as a MemoryBuffer. Note 84 /// that InputData must be null terminated if RequiresNullTerminator is true. 85 static MemoryBuffer *getMemBuffer(StringRef InputData, 86 StringRef BufferName = "", 87 bool RequiresNullTerminator = true); 88 89 /// getMemBufferCopy - Open the specified memory range as a MemoryBuffer, 90 /// copying the contents and taking ownership of it. InputData does not 91 /// have to be null terminated. 92 static MemoryBuffer *getMemBufferCopy(StringRef InputData, 93 StringRef BufferName = ""); 94 95 /// getNewMemBuffer - Allocate a new MemoryBuffer of the specified size that 96 /// is completely initialized to zeros. Note that the caller should 97 /// initialize the memory allocated by this method. The memory is owned by 98 /// the MemoryBuffer object. 99 static MemoryBuffer *getNewMemBuffer(size_t Size, StringRef BufferName = ""); 100 101 /// getNewUninitMemBuffer - Allocate a new MemoryBuffer of the specified size 102 /// that is not initialized. Note that the caller should initialize the 103 /// memory allocated by this method. The memory is owned by the MemoryBuffer 104 /// object. 105 static MemoryBuffer *getNewUninitMemBuffer(size_t Size, 106 StringRef BufferName = ""); 107 108 /// getSTDIN - Read all of stdin into a file buffer, and return it. 109 /// If an error occurs, this returns null and sets ec. 110 static error_code getSTDIN(OwningPtr<MemoryBuffer> &result); 111 112 113 /// getFileOrSTDIN - Open the specified file as a MemoryBuffer, or open stdin 114 /// if the Filename is "-". If an error occurs, this returns null and sets 115 /// ec. 116 static error_code getFileOrSTDIN(StringRef Filename, 117 OwningPtr<MemoryBuffer> &result, 118 int64_t FileSize = -1); 119 static error_code getFileOrSTDIN(const char *Filename, 120 OwningPtr<MemoryBuffer> &result, 121 int64_t FileSize = -1); 122 123 124 //===--------------------------------------------------------------------===// 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 } // end namespace llvm 140 141 #endif 142
