1 //===-- llvm/Support/FormattedStream.h - Formatted streams ------*- 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 contains raw_ostream implementations for streams to do 11 // things like pretty-print comments. 12 // 13 //===----------------------------------------------------------------------===// 14 15 #ifndef LLVM_SUPPORT_FORMATTEDSTREAM_H 16 #define LLVM_SUPPORT_FORMATTEDSTREAM_H 17 18 #include "llvm/Support/raw_ostream.h" 19 #include <utility> 20 21 namespace llvm { 22 23 /// formatted_raw_ostream - A raw_ostream that wraps another one and keeps track 24 /// of line and column position, allowing padding out to specific column 25 /// boundaries and querying the number of lines written to the stream. 26 /// 27 class formatted_raw_ostream : public raw_ostream { 28 public: 29 /// DELETE_STREAM - Tell the destructor to delete the held stream. 30 /// 31 static const bool DELETE_STREAM = true; 32 33 /// PRESERVE_STREAM - Tell the destructor to not delete the held 34 /// stream. 35 /// 36 static const bool PRESERVE_STREAM = false; 37 38 private: 39 /// TheStream - The real stream we output to. We set it to be 40 /// unbuffered, since we're already doing our own buffering. 41 /// 42 raw_ostream *TheStream; 43 44 /// DeleteStream - Do we need to delete TheStream in the 45 /// destructor? 46 /// 47 bool DeleteStream; 48 49 /// Position - The current output column and line of the data that's 50 /// been flushed and the portion of the buffer that's been 51 /// scanned. The line and column scheme is zero-based. 52 /// 53 std::pair<unsigned, unsigned> Position; 54 55 /// Scanned - This points to one past the last character in the 56 /// buffer we've scanned. 57 /// 58 const char *Scanned; 59 60 virtual void write_impl(const char *Ptr, size_t Size) LLVM_OVERRIDE; 61 62 /// current_pos - Return the current position within the stream, 63 /// not counting the bytes currently in the buffer. 64 virtual uint64_t current_pos() const LLVM_OVERRIDE { 65 // Our current position in the stream is all the contents which have been 66 // written to the underlying stream (*not* the current position of the 67 // underlying stream). 68 return TheStream->tell(); 69 } 70 71 /// ComputePosition - Examine the given output buffer and figure out the new 72 /// position after output. 73 /// 74 void ComputePosition(const char *Ptr, size_t size); 75 76 public: 77 /// formatted_raw_ostream - Open the specified file for 78 /// writing. If an error occurs, information about the error is 79 /// put into ErrorInfo, and the stream should be immediately 80 /// destroyed; the string will be empty if no error occurred. 81 /// 82 /// As a side effect, the given Stream is set to be Unbuffered. 83 /// This is because formatted_raw_ostream does its own buffering, 84 /// so it doesn't want another layer of buffering to be happening 85 /// underneath it. 86 /// 87 formatted_raw_ostream(raw_ostream &Stream, bool Delete = false) 88 : raw_ostream(), TheStream(0), DeleteStream(false), Position(0, 0) { 89 setStream(Stream, Delete); 90 } 91 explicit formatted_raw_ostream() 92 : raw_ostream(), TheStream(0), DeleteStream(false), Position(0, 0) { 93 Scanned = 0; 94 } 95 96 ~formatted_raw_ostream() { 97 flush(); 98 releaseStream(); 99 } 100 101 void setStream(raw_ostream &Stream, bool Delete = false) { 102 releaseStream(); 103 104 TheStream = &Stream; 105 DeleteStream = Delete; 106 107 // This formatted_raw_ostream inherits from raw_ostream, so it'll do its 108 // own buffering, and it doesn't need or want TheStream to do another 109 // layer of buffering underneath. Resize the buffer to what TheStream 110 // had been using, and tell TheStream not to do its own buffering. 111 if (size_t BufferSize = TheStream->GetBufferSize()) 112 SetBufferSize(BufferSize); 113 else 114 SetUnbuffered(); 115 TheStream->SetUnbuffered(); 116 117 Scanned = 0; 118 } 119 120 /// PadToColumn - Align the output to some column number. If the current 121 /// column is already equal to or more than NewCol, PadToColumn inserts one 122 /// space. 123 /// 124 /// \param NewCol - The column to move to. 125 formatted_raw_ostream &PadToColumn(unsigned NewCol); 126 127 /// getColumn - Return the column number 128 unsigned getColumn() { return Position.first; } 129 130 /// getLine - Return the line number 131 unsigned getLine() { return Position.second; } 132 133 private: 134 void releaseStream() { 135 // Delete the stream if needed. Otherwise, transfer the buffer 136 // settings from this raw_ostream back to the underlying stream. 137 if (!TheStream) 138 return; 139 if (DeleteStream) 140 delete TheStream; 141 else if (size_t BufferSize = GetBufferSize()) 142 TheStream->SetBufferSize(BufferSize); 143 else 144 TheStream->SetUnbuffered(); 145 } 146 }; 147 148 /// fouts() - This returns a reference to a formatted_raw_ostream for 149 /// standard output. Use it like: fouts() << "foo" << "bar"; 150 formatted_raw_ostream &fouts(); 151 152 /// ferrs() - This returns a reference to a formatted_raw_ostream for 153 /// standard error. Use it like: ferrs() << "foo" << "bar"; 154 formatted_raw_ostream &ferrs(); 155 156 /// fdbgs() - This returns a reference to a formatted_raw_ostream for 157 /// debug output. Use it like: fdbgs() << "foo" << "bar"; 158 formatted_raw_ostream &fdbgs(); 159 160 } // end llvm namespace 161 162 163 #endif 164
