LLVM 18.0.0git
FormattedStream.h
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1//===-- llvm/Support/FormattedStream.h - Formatted streams ------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file contains raw_ostream implementations for streams to do
10// things like pretty-print comments.
11//
12//===----------------------------------------------------------------------===//
13
14#ifndef LLVM_SUPPORT_FORMATTEDSTREAM_H
15#define LLVM_SUPPORT_FORMATTEDSTREAM_H
16
19#include <utility>
20
21namespace 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. This
26/// assumes that the contents of the stream is valid UTF-8 encoded text. This
27/// doesn't attempt to handle everything Unicode can do (combining characters,
28/// right-to-left markers, etc), but should cover the cases likely to appear in
29/// source code or diagnostic messages.
31 /// TheStream - The real stream we output to. We set it to be
32 /// unbuffered, since we're already doing our own buffering.
33 ///
34 raw_ostream *TheStream;
35
36 /// Position - The current output column and line of the data that's
37 /// been flushed and the portion of the buffer that's been
38 /// scanned. The line and column scheme is zero-based.
39 ///
40 std::pair<unsigned, unsigned> Position;
41
42 /// Scanned - This points to one past the last character in the
43 /// buffer we've scanned.
44 ///
45 const char *Scanned;
46
47 /// PartialUTF8Char - Either empty or a prefix of a UTF-8 code unit sequence
48 /// for a Unicode scalar value which should be prepended to the buffer for the
49 /// next call to ComputePosition. This is needed when the buffer is flushed
50 /// when it ends part-way through the UTF-8 encoding of a Unicode scalar
51 /// value, so that we can compute the display width of the character once we
52 /// have the rest of it.
53 SmallString<4> PartialUTF8Char;
54
55 void write_impl(const char *Ptr, size_t Size) override;
56
57 /// current_pos - Return the current position within the stream,
58 /// not counting the bytes currently in the buffer.
59 uint64_t current_pos() const override {
60 // Our current position in the stream is all the contents which have been
61 // written to the underlying stream (*not* the current position of the
62 // underlying stream).
63 return TheStream->tell();
64 }
65
66 /// ComputePosition - Examine the given output buffer and figure out the new
67 /// position after output. This is safe to call multiple times on the same
68 /// buffer, as it records the most recently scanned character and resumes from
69 /// there when the buffer has not been flushed.
70 void ComputePosition(const char *Ptr, size_t size);
71
72 /// UpdatePosition - scan the characters in [Ptr, Ptr+Size), and update the
73 /// line and column numbers. Unlike ComputePosition, this must be called
74 /// exactly once on each region of the buffer.
75 void UpdatePosition(const char *Ptr, size_t Size);
76
77 void setStream(raw_ostream &Stream) {
78 releaseStream();
79
80 TheStream = &Stream;
81
82 // This formatted_raw_ostream inherits from raw_ostream, so it'll do its
83 // own buffering, and it doesn't need or want TheStream to do another
84 // layer of buffering underneath. Resize the buffer to what TheStream
85 // had been using, and tell TheStream not to do its own buffering.
86 if (size_t BufferSize = TheStream->GetBufferSize())
87 SetBufferSize(BufferSize);
88 else
90 TheStream->SetUnbuffered();
91
92 Scanned = nullptr;
93 }
94
95public:
96 /// formatted_raw_ostream - Open the specified file for
97 /// writing. If an error occurs, information about the error is
98 /// put into ErrorInfo, and the stream should be immediately
99 /// destroyed; the string will be empty if no error occurred.
100 ///
101 /// As a side effect, the given Stream is set to be Unbuffered.
102 /// This is because formatted_raw_ostream does its own buffering,
103 /// so it doesn't want another layer of buffering to be happening
104 /// underneath it.
105 ///
107 : TheStream(nullptr), Position(0, 0) {
108 setStream(Stream);
109 }
110 explicit formatted_raw_ostream() : TheStream(nullptr), Position(0, 0) {
111 Scanned = nullptr;
112 }
113
115 flush();
116 releaseStream();
117 }
118
119 /// PadToColumn - Align the output to some column number. If the current
120 /// column is already equal to or more than NewCol, PadToColumn inserts one
121 /// space.
122 ///
123 /// \param NewCol - The column to move to.
124 formatted_raw_ostream &PadToColumn(unsigned NewCol);
125
126 unsigned getColumn() {
127 // Calculate current position, taking buffer contents into account.
128 ComputePosition(getBufferStart(), GetNumBytesInBuffer());
129 return Position.first;
130 }
131
132 unsigned getLine() {
133 // Calculate current position, taking buffer contents into account.
134 ComputePosition(getBufferStart(), GetNumBytesInBuffer());
135 return Position.second;
136 }
137
139 TheStream->resetColor();
140 return *this;
141 }
142
144 TheStream->reverseColor();
145 return *this;
146 }
147
148 raw_ostream &changeColor(enum Colors Color, bool Bold, bool BG) override {
149 TheStream->changeColor(Color, Bold, BG);
150 return *this;
151 }
152
153 bool is_displayed() const override {
154 return TheStream->is_displayed();
155 }
156
157private:
158 void releaseStream() {
159 // Transfer the buffer settings from this raw_ostream back to the underlying
160 // stream.
161 if (!TheStream)
162 return;
163 if (size_t BufferSize = GetBufferSize())
164 TheStream->SetBufferSize(BufferSize);
165 else
166 TheStream->SetUnbuffered();
167 }
168};
169
170/// fouts() - This returns a reference to a formatted_raw_ostream for
171/// standard output. Use it like: fouts() << "foo" << "bar";
172formatted_raw_ostream &fouts();
173
174/// ferrs() - This returns a reference to a formatted_raw_ostream for
175/// standard error. Use it like: ferrs() << "foo" << "bar";
176formatted_raw_ostream &ferrs();
177
178/// fdbgs() - This returns a reference to a formatted_raw_ostream for
179/// debug output. Use it like: fdbgs() << "foo" << "bar";
180formatted_raw_ostream &fdbgs();
181
182} // end llvm namespace
183
184
185#endif
uint64_t Size
This file defines the SmallString class.
SmallString - A SmallString is just a SmallVector with methods and accessors that make it work better...
Definition: SmallString.h:26
formatted_raw_ostream - A raw_ostream that wraps another one and keeps track of line and column posit...
bool is_displayed() const override
This function determines if this stream is connected to a "tty" or "console" window.
formatted_raw_ostream & PadToColumn(unsigned NewCol)
PadToColumn - Align the output to some column number.
raw_ostream & resetColor() override
Resets the colors to terminal defaults.
raw_ostream & changeColor(enum Colors Color, bool Bold, bool BG) override
Changes the foreground color of text that will be output from this point forward.
formatted_raw_ostream(raw_ostream &Stream)
formatted_raw_ostream - Open the specified file for writing.
raw_ostream & reverseColor() override
Reverses the foreground and background colors.
This class implements an extremely fast bulk output stream that can only output to a stream.
Definition: raw_ostream.h:52
uint64_t tell() const
tell - Return the current offset with the file.
Definition: raw_ostream.h:134
void SetBufferSize(size_t Size)
Set the stream to be buffered, using the specified buffer size.
Definition: raw_ostream.h:154
virtual raw_ostream & changeColor(enum Colors Color, bool Bold=false, bool BG=false)
Changes the foreground color of text that will be output from this point forward.
size_t GetBufferSize() const
Definition: raw_ostream.h:159
virtual raw_ostream & resetColor()
Resets the colors to terminal defaults.
virtual raw_ostream & reverseColor()
Reverses the foreground and background colors.
void SetUnbuffered()
Set the stream to be unbuffered.
Definition: raw_ostream.h:172
virtual bool is_displayed() const
This function determines if this stream is connected to a "tty" or "console" window.
Definition: raw_ostream.h:334
const char * getBufferStart() const
Return the beginning of the current stream buffer, or 0 if the stream is unbuffered.
Definition: raw_ostream.h:387
size_t GetNumBytesInBuffer() const
Definition: raw_ostream.h:177
This is an optimization pass for GlobalISel generic memory operations.
Definition: AddressRanges.h:18
auto size(R &&Range, std::enable_if_t< std::is_base_of< std::random_access_iterator_tag, typename std::iterator_traits< decltype(Range.begin())>::iterator_category >::value, void > *=nullptr)
Get the size of a range.
Definition: STLExtras.h:1684
formatted_raw_ostream & fdbgs()
fdbgs() - This returns a reference to a formatted_raw_ostream for debug output.
formatted_raw_ostream & fouts()
fouts() - This returns a reference to a formatted_raw_ostream for standard output.
formatted_raw_ostream & ferrs()
ferrs() - This returns a reference to a formatted_raw_ostream for standard error.