1 //===--- raw_ostream.h - Raw output stream ----------------------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file defines the raw_ostream class.
12 //===----------------------------------------------------------------------===//
14 #ifndef LLVM_SUPPORT_RAW_OSTREAM_H
15 #define LLVM_SUPPORT_RAW_OSTREAM_H
17 #include "llvm/ADT/StringRef.h"
18 #include "llvm/Support/DataTypes.h"
21 class format_object_base;
23 class SmallVectorImpl;
25 /// raw_ostream - This class implements an extremely fast bulk output stream
26 /// that can *only* output to a stream. It does not support seeking, reopening,
27 /// rewinding, line buffered disciplines etc. It is a simple buffer that outputs
28 /// a chunk at a time.
31 // Do not implement. raw_ostream is noncopyable.
32 void operator=(const raw_ostream &);
33 raw_ostream(const raw_ostream &);
35 /// The buffer is handled in such a way that the buffer is
36 /// uninitialized, unbuffered, or out of space when OutBufCur >=
37 /// OutBufEnd. Thus a single comparison suffices to determine if we
38 /// need to take the slow path to write a single character.
40 /// The buffer is in one of three states:
41 /// 1. Unbuffered (BufferMode == Unbuffered)
42 /// 1. Uninitialized (BufferMode != Unbuffered && OutBufStart == 0).
43 /// 2. Buffered (BufferMode != Unbuffered && OutBufStart != 0 &&
44 /// OutBufEnd - OutBufStart >= 1).
46 /// If buffered, then the raw_ostream owns the buffer if (BufferMode ==
47 /// InternalBuffer); otherwise the buffer has been set via SetBuffer and is
48 /// managed by the subclass.
50 /// If a subclass installs an external buffer using SetBuffer then it can wait
51 /// for a \see write_impl() call to handle the data which has been put into
53 char *OutBufStart, *OutBufEnd, *OutBufCur;
62 // color order matches ANSI escape sequence, don't change
75 explicit raw_ostream(bool unbuffered=false)
76 : BufferMode(unbuffered ? Unbuffered : InternalBuffer) {
77 // Start out ready to flush.
78 OutBufStart = OutBufEnd = OutBufCur = 0;
81 virtual ~raw_ostream();
83 /// tell - Return the current offset with the file.
84 uint64_t tell() const { return current_pos() + GetNumBytesInBuffer(); }
86 //===--------------------------------------------------------------------===//
87 // Configuration Interface
88 //===--------------------------------------------------------------------===//
90 /// SetBuffered - Set the stream to be buffered, with an automatically
91 /// determined buffer size.
94 /// SetBufferSize - Set the stream to be buffered, using the
95 /// specified buffer size.
96 void SetBufferSize(size_t Size) {
98 SetBufferAndMode(new char[Size], Size, InternalBuffer);
101 size_t GetBufferSize() const {
102 // If we're supposed to be buffered but haven't actually gotten around
103 // to allocating the buffer yet, return the value that would be used.
104 if (BufferMode != Unbuffered && OutBufStart == 0)
105 return preferred_buffer_size();
107 // Otherwise just return the size of the allocated buffer.
108 return OutBufEnd - OutBufStart;
111 /// SetUnbuffered - Set the stream to be unbuffered. When
112 /// unbuffered, the stream will flush after every write. This routine
113 /// will also flush the buffer immediately when the stream is being
114 /// set to unbuffered.
115 void SetUnbuffered() {
117 SetBufferAndMode(0, 0, Unbuffered);
120 size_t GetNumBytesInBuffer() const {
121 return OutBufCur - OutBufStart;
124 //===--------------------------------------------------------------------===//
125 // Data Output Interface
126 //===--------------------------------------------------------------------===//
129 if (OutBufCur != OutBufStart)
133 raw_ostream &operator<<(char C) {
134 if (OutBufCur >= OutBufEnd)
140 raw_ostream &operator<<(unsigned char C) {
141 if (OutBufCur >= OutBufEnd)
147 raw_ostream &operator<<(signed char C) {
148 if (OutBufCur >= OutBufEnd)
154 raw_ostream &operator<<(StringRef Str) {
155 // Inline fast path, particularly for strings with a known length.
156 size_t Size = Str.size();
158 // Make sure we can use the fast path.
159 if (OutBufCur+Size > OutBufEnd)
160 return write(Str.data(), Size);
162 memcpy(OutBufCur, Str.data(), Size);
167 raw_ostream &operator<<(const char *Str) {
168 // Inline fast path, particularly for constant strings where a sufficiently
169 // smart compiler will simplify strlen.
171 return this->operator<<(StringRef(Str));
174 raw_ostream &operator<<(const std::string &Str) {
175 // Avoid the fast path, it would only increase code size for a marginal win.
176 return write(Str.data(), Str.length());
179 raw_ostream &operator<<(unsigned long N);
180 raw_ostream &operator<<(long N);
181 raw_ostream &operator<<(unsigned long long N);
182 raw_ostream &operator<<(long long N);
183 raw_ostream &operator<<(const void *P);
184 raw_ostream &operator<<(unsigned int N) {
185 return this->operator<<(static_cast<unsigned long>(N));
188 raw_ostream &operator<<(int N) {
189 return this->operator<<(static_cast<long>(N));
192 raw_ostream &operator<<(double N);
194 /// write_hex - Output \p N in hexadecimal, without any prefix or padding.
195 raw_ostream &write_hex(unsigned long long N);
197 /// write_escaped - Output \p Str, turning '\\', '\t', '\n', '"', and
198 /// anything that doesn't satisfy std::isprint into an escape sequence.
199 raw_ostream &write_escaped(StringRef Str, bool UseHexEscapes = false);
201 raw_ostream &write(unsigned char C);
202 raw_ostream &write(const char *Ptr, size_t Size);
204 // Formatted output, see the format() function in Support/Format.h.
205 raw_ostream &operator<<(const format_object_base &Fmt);
207 /// indent - Insert 'NumSpaces' spaces.
208 raw_ostream &indent(unsigned NumSpaces);
211 /// Changes the foreground color of text that will be output from this point
213 /// @param Color ANSI color to use, the special SAVEDCOLOR can be used to
214 /// change only the bold attribute, and keep colors untouched
215 /// @param Bold bold/brighter text, default false
216 /// @param BG if true change the background, default: change foreground
217 /// @returns itself so it can be used within << invocations
218 virtual raw_ostream &changeColor(enum Colors Color,
227 /// Resets the colors to terminal defaults. Call this when you are done
228 /// outputting colored text, or before program exit.
229 virtual raw_ostream &resetColor() { return *this; }
231 /// Reverses the forground and background colors.
232 virtual raw_ostream &reverseColor() { return *this; }
234 /// This function determines if this stream is connected to a "tty" or
235 /// "console" window. That is, the output would be displayed to the user
236 /// rather than being put on a pipe or stored in a file.
237 virtual bool is_displayed() const { return false; }
239 /// This function determines if this stream is displayed and supports colors.
240 virtual bool has_colors() const { return is_displayed(); }
242 //===--------------------------------------------------------------------===//
243 // Subclass Interface
244 //===--------------------------------------------------------------------===//
247 /// write_impl - The is the piece of the class that is implemented
248 /// by subclasses. This writes the \p Size bytes starting at
249 /// \p Ptr to the underlying stream.
251 /// This function is guaranteed to only be called at a point at which it is
252 /// safe for the subclass to install a new buffer via SetBuffer.
254 /// \param Ptr The start of the data to be written. For buffered streams this
255 /// is guaranteed to be the start of the buffer.
257 /// \param Size The number of bytes to be written.
259 /// \invariant { Size > 0 }
260 virtual void write_impl(const char *Ptr, size_t Size) = 0;
262 // An out of line virtual method to provide a home for the class vtable.
263 virtual void handle();
265 /// current_pos - Return the current position within the stream, not
266 /// counting the bytes currently in the buffer.
267 virtual uint64_t current_pos() const = 0;
270 /// SetBuffer - Use the provided buffer as the raw_ostream buffer. This is
271 /// intended for use only by subclasses which can arrange for the output to go
272 /// directly into the desired output buffer, instead of being copied on each
274 void SetBuffer(char *BufferStart, size_t Size) {
275 SetBufferAndMode(BufferStart, Size, ExternalBuffer);
278 /// preferred_buffer_size - Return an efficient buffer size for the
279 /// underlying output mechanism.
280 virtual size_t preferred_buffer_size() const;
282 /// getBufferStart - Return the beginning of the current stream buffer, or 0
283 /// if the stream is unbuffered.
284 const char *getBufferStart() const { return OutBufStart; }
286 //===--------------------------------------------------------------------===//
288 //===--------------------------------------------------------------------===//
290 /// SetBufferAndMode - Install the given buffer and mode.
291 void SetBufferAndMode(char *BufferStart, size_t Size, BufferKind Mode);
293 /// flush_nonempty - Flush the current buffer, which is known to be
294 /// non-empty. This outputs the currently buffered data and resets
295 /// the buffer to empty.
296 void flush_nonempty();
298 /// copy_to_buffer - Copy data into the buffer. Size must not be
299 /// greater than the number of unused bytes in the buffer.
300 void copy_to_buffer(const char *Ptr, size_t Size);
303 //===----------------------------------------------------------------------===//
304 // File Output Streams
305 //===----------------------------------------------------------------------===//
307 /// raw_fd_ostream - A raw_ostream that writes to a file descriptor.
309 class raw_fd_ostream : public raw_ostream {
313 /// Error This flag is true if an error of any kind has been detected.
317 /// Controls whether the stream should attempt to use atomic writes, when
319 bool UseAtomicWrites;
323 /// write_impl - See raw_ostream::write_impl.
324 virtual void write_impl(const char *Ptr, size_t Size);
326 /// current_pos - Return the current position within the stream, not
327 /// counting the bytes currently in the buffer.
328 virtual uint64_t current_pos() const { return pos; }
330 /// preferred_buffer_size - Determine an efficient buffer size.
331 virtual size_t preferred_buffer_size() const;
333 /// error_detected - Set the flag indicating that an output error has
334 /// been encountered.
335 void error_detected() { Error = true; }
340 /// F_Excl - When opening a file, this flag makes raw_fd_ostream
341 /// report an error if the file already exists.
344 /// F_Append - When opening a file, if it already exists append to the
345 /// existing file instead of returning an error. This may not be specified
349 /// F_Binary - The file should be opened in binary mode on platforms that
350 /// make this distinction.
354 /// raw_fd_ostream - Open the specified file for writing. If an error occurs,
355 /// information about the error is put into ErrorInfo, and the stream should
356 /// be immediately destroyed; the string will be empty if no error occurred.
357 /// This allows optional flags to control how the file will be opened.
359 /// As a special case, if Filename is "-", then the stream will use
360 /// STDOUT_FILENO instead of opening a file. Note that it will still consider
361 /// itself to own the file descriptor. In particular, it will close the
362 /// file descriptor when it is done (this is necessary to detect
364 raw_fd_ostream(const char *Filename, std::string &ErrorInfo,
367 /// raw_fd_ostream ctor - FD is the file descriptor that this writes to. If
368 /// ShouldClose is true, this closes the file when the stream is destroyed.
369 raw_fd_ostream(int fd, bool shouldClose, bool unbuffered=false);
373 /// close - Manually flush the stream and close the file.
374 /// Note that this does not call fsync.
377 /// seek - Flushes the stream and repositions the underlying file descriptor
378 /// position to the offset specified from the beginning of the file.
379 uint64_t seek(uint64_t off);
381 /// SetUseAtomicWrite - Set the stream to attempt to use atomic writes for
382 /// individual output routines where possible.
384 /// Note that because raw_ostream's are typically buffered, this flag is only
385 /// sensible when used on unbuffered streams which will flush their output
387 void SetUseAtomicWrites(bool Value) {
388 UseAtomicWrites = Value;
391 virtual raw_ostream &changeColor(enum Colors colors, bool bold=false,
393 virtual raw_ostream &resetColor();
395 virtual raw_ostream &reverseColor();
397 virtual bool is_displayed() const;
399 virtual bool has_colors() const;
401 /// has_error - Return the value of the flag in this raw_fd_ostream indicating
402 /// whether an output error has been encountered.
403 /// This doesn't implicitly flush any pending output. Also, it doesn't
404 /// guarantee to detect all errors unless the stream has been closed.
405 bool has_error() const {
409 /// clear_error - Set the flag read by has_error() to false. If the error
410 /// flag is set at the time when this raw_ostream's destructor is called,
411 /// report_fatal_error is called to report the error. Use clear_error()
412 /// after handling the error to avoid this behavior.
414 /// "Errors should never pass silently.
415 /// Unless explicitly silenced."
416 /// - from The Zen of Python, by Tim Peters
423 /// outs() - This returns a reference to a raw_ostream for standard output.
424 /// Use it like: outs() << "foo" << "bar";
427 /// errs() - This returns a reference to a raw_ostream for standard error.
428 /// Use it like: errs() << "foo" << "bar";
431 /// nulls() - This returns a reference to a raw_ostream which simply discards
433 raw_ostream &nulls();
435 //===----------------------------------------------------------------------===//
436 // Output Stream Adaptors
437 //===----------------------------------------------------------------------===//
439 /// raw_string_ostream - A raw_ostream that writes to an std::string. This is a
440 /// simple adaptor class. This class does not encounter output errors.
441 class raw_string_ostream : public raw_ostream {
444 /// write_impl - See raw_ostream::write_impl.
445 virtual void write_impl(const char *Ptr, size_t Size);
447 /// current_pos - Return the current position within the stream, not
448 /// counting the bytes currently in the buffer.
449 virtual uint64_t current_pos() const { return OS.size(); }
451 explicit raw_string_ostream(std::string &O) : OS(O) {}
452 ~raw_string_ostream();
454 /// str - Flushes the stream contents to the target string and returns
455 /// the string's reference.
462 /// raw_svector_ostream - A raw_ostream that writes to an SmallVector or
463 /// SmallString. This is a simple adaptor class. This class does not
464 /// encounter output errors.
465 class raw_svector_ostream : public raw_ostream {
466 SmallVectorImpl<char> &OS;
468 /// write_impl - See raw_ostream::write_impl.
469 virtual void write_impl(const char *Ptr, size_t Size);
471 /// current_pos - Return the current position within the stream, not
472 /// counting the bytes currently in the buffer.
473 virtual uint64_t current_pos() const;
475 /// Construct a new raw_svector_ostream.
477 /// \param O The vector to write to; this should generally have at least 128
478 /// bytes free to avoid any extraneous memory overhead.
479 explicit raw_svector_ostream(SmallVectorImpl<char> &O);
480 ~raw_svector_ostream();
482 /// resync - This is called when the SmallVector we're appending to is changed
483 /// outside of the raw_svector_ostream's control. It is only safe to do this
484 /// if the raw_svector_ostream has previously been flushed.
487 /// str - Flushes the stream contents to the target vector and return a
488 /// StringRef for the vector contents.
492 /// raw_null_ostream - A raw_ostream that discards all output.
493 class raw_null_ostream : public raw_ostream {
494 /// write_impl - See raw_ostream::write_impl.
495 virtual void write_impl(const char *Ptr, size_t size);
497 /// current_pos - Return the current position within the stream, not
498 /// counting the bytes currently in the buffer.
499 virtual uint64_t current_pos() const;
502 explicit raw_null_ostream() {}
506 } // end llvm namespace