FormattedStream.h revision 7aaad71722aeb26f14c8523ee55df91e38837a02 
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
31    /// PRESERVE_STREAM - Tell the destructor to not delete the held
32    /// stream.
33    ///
34    const static bool PRESERVE_STREAM = false;
35
36    /// MAX_COLUMN_PAD - This is the maximum column padding we ever
37    /// expect to see.
38    ///
39    const static unsigned MAX_COLUMN_PAD = 100;
40
41  private:
42    /// TheStream - The real stream we output to. We set it to be
43    /// unbuffered, since we're already doing our own buffering.
44    ///
45    raw_ostream *TheStream;
46
47    /// DeleteStream - Do we need to delete TheStream in the
48    /// destructor?
49    ///
50    bool DeleteStream;
51
52    /// ColumnFlushed - The current output column of the data that's
53    /// been flushed.  The column scheme is zero-based.
54    ///
55    unsigned ColumnFlushed;
56
57    virtual void write_impl(const char *Ptr, size_t Size) {
58      ComputeColumn(ColumnFlushed);
59      TheStream->write(Ptr, Size);
60    }
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() {
65      // This has the same effect as calling TheStream.current_pos(),
66      // but that interface is private.
67      return TheStream->tell() - TheStream->GetNumBytesInBuffer();
68    }
69
70    /// ComputeColumn - Examine the current buffer and figure out
71    /// which column we're in.
72    ///
73    void ComputeColumn(unsigned &Column);
74
75  public:
76    /// formatted_raw_ostream - Open the specified file for
77    /// writing. If an error occurs, information about the error is
78    /// put into ErrorInfo, and the stream should be immediately
79    /// destroyed; the string will be empty if no error occurred.
80    ///
81    /// As a side effect, the given Stream is set to be Unbuffered.
82    /// This is because formatted_raw_ostream does its own buffering,
83    /// so it doesn't want another layer of buffering to be happening
84    /// underneath it.
85    ///
86    formatted_raw_ostream(raw_ostream &Stream, bool Delete = false)
87      : raw_ostream(), TheStream(0), DeleteStream(false), ColumnFlushed(0) {
88      setStream(Stream, Delete);
89    }
90    explicit formatted_raw_ostream()
91      : raw_ostream(), TheStream(0), DeleteStream(false), ColumnFlushed(0) {}
92
93    ~formatted_raw_ostream() {
94      if (DeleteStream)
95        delete TheStream;
96    }
97
98    void setStream(raw_ostream &Stream, bool Delete = false) {
99      if (DeleteStream)
100        delete TheStream;
101
102      TheStream = &Stream;
103      DeleteStream = Delete;
104
105      // This formatted_raw_ostream inherits from raw_ostream, so it'll do its
106      // own buffering, and it doesn't need or want TheStream to do another
107      // layer of buffering underneath. Resize the buffer to what TheStream
108      // had been using, and tell TheStream not to do its own buffering.
109      TheStream->flush();
110      if (size_t BufferSize = TheStream->GetNumBytesInBuffer())
111        SetBufferSize(BufferSize);
112      TheStream->SetUnbuffered();
113    }
114
115    /// PadToColumn - Align the output to some column number.
116    ///
117    /// \param NewCol - The column to move to.
118    /// \param MinPad - The minimum space to give after the most
119    /// recent I/O, even if the current column + minpad > newcol.
120    ///
121    void PadToColumn(unsigned NewCol, unsigned MinPad = 0);
122  };
123
124/// fouts() - This returns a reference to a formatted_raw_ostream for
125/// standard output.  Use it like: fouts() << "foo" << "bar";
126formatted_raw_ostream &fouts();
127
128/// ferrs() - This returns a reference to a formatted_raw_ostream for
129/// standard error.  Use it like: ferrs() << "foo" << "bar";
130formatted_raw_ostream &ferrs();
131
132} // end llvm namespace
133
134
135#endif
136