FormattedStream.h revision 3724b482589af30978f39b50685ef5432863763b
1//===-- llvm/CodeGen/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 20namespace llvm 21{ 22 /// formatted_raw_ostream - Formatted raw_fd_ostream to handle 23 /// asm-specific constructs. 24 /// 25 class formatted_raw_ostream : public raw_ostream { 26 public: 27 /// DELETE_STREAM - Tell the destructor to delete the held stream. 28 /// 29 const static bool DELETE_STREAM = true; 30 /// PRESERVE_STREAM - Tell the destructor to not delete the held 31 /// stream. 32 /// 33 const static bool PRESERVE_STREAM = false; 34 35 private: 36 /// TheStream - The real stream we output to. We set it to be 37 /// unbuffered, since we're already doing our own buffering. 38 /// 39 raw_ostream *TheStream; 40 /// DeleteStream - Do we need to delete TheStream in the 41 /// destructor? 42 /// 43 bool DeleteStream; 44 45 /// Column - The current output column of the stream. The column 46 /// scheme is zero-based. 47 /// 48 unsigned Column; 49 50 virtual void write_impl(const char *Ptr, size_t Size) { 51 ComputeColumn(Ptr, Size); 52 TheStream->write(Ptr, Size); 53 } 54 55 /// current_pos - Return the current position within the stream, 56 /// not counting the bytes currently in the buffer. 57 virtual uint64_t current_pos() { 58 // This has the same effect as calling TheStream.current_pos(), 59 // but that interface is private. 60 return TheStream->tell() - TheStream->GetNumBytesInBuffer(); 61 } 62 63 /// ComputeColumn - Examine the current output and figure out 64 /// which column we end up in after output. 65 /// 66 void ComputeColumn(const char *Ptr, size_t Size); 67 68 public: 69 /// formatted_raw_ostream - Open the specified file for 70 /// writing. If an error occurs, information about the error is 71 /// put into ErrorInfo, and the stream should be immediately 72 /// destroyed; the string will be empty if no error occurred. 73 /// 74 /// As a side effect, the given Stream is set to be Unbuffered. 75 /// This is because formatted_raw_ostream does its own buffering, 76 /// so it doesn't want another layer of buffering to be happening 77 /// underneath it. 78 /// 79 formatted_raw_ostream(raw_ostream &Stream, bool Delete = false) 80 : raw_ostream(), TheStream(&Stream), DeleteStream(Delete), Column(0) { 81 // This formatted_raw_ostream inherits from raw_ostream, so it'll do its 82 // own buffering, and it doesn't need or want TheStream to do another 83 // layer of buffering underneath. Resize the buffer to what TheStream 84 // had been using, and tell TheStream not to do its own buffering. 85 TheStream->flush(); 86 if (size_t BufferSize = TheStream->GetNumBytesInBuffer()) 87 SetBufferSize(BufferSize); 88 TheStream->SetUnbuffered(); 89 } 90 explicit formatted_raw_ostream() 91 : raw_ostream(), TheStream(0), DeleteStream(false), Column(0) {} 92 93 ~formatted_raw_ostream() { 94 if (DeleteStream) 95 delete TheStream; 96 } 97 98 void setStream(raw_ostream &Stream, bool Delete = false) { 99 TheStream = &Stream; 100 DeleteStream = Delete; 101 102 // Avoid double-buffering, as above. 103 TheStream->flush(); 104 if (size_t BufferSize = TheStream->GetNumBytesInBuffer()) 105 SetBufferSize(BufferSize); 106 TheStream->SetUnbuffered(); 107 } 108 109 /// PadToColumn - Align the output to some column number. 110 /// 111 /// \param NewCol - The column to move to. 112 /// \param MinPad - The minimum space to give after the most 113 /// recent I/O, even if the current column + minpad > newcol. 114 /// 115 void PadToColumn(unsigned NewCol, unsigned MinPad = 0); 116 }; 117 118/// fouts() - This returns a reference to a formatted_raw_ostream for 119/// standard output. Use it like: fouts() << "foo" << "bar"; 120formatted_raw_ostream &fouts(); 121 122/// ferrs() - This returns a reference to a formatted_raw_ostream for 123/// standard error. Use it like: ferrs() << "foo" << "bar"; 124formatted_raw_ostream &ferrs(); 125 126} // end llvm namespace 127 128 129#endif 130