1 //===--- raw_ostream.h - Raw output stream ----------------------*- 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 defines the raw_ostream class. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #ifndef LLVM_SUPPORT_RAW_OSTREAM_H 15 #define LLVM_SUPPORT_RAW_OSTREAM_H 16 17 #include "llvm/ADT/StringRef.h" 18 #include "llvm/Support/DataTypes.h" 19 20 namespace llvm { 21 class format_object_base; 22 template <typename T> 23 class SmallVectorImpl; 24 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. 29 class raw_ostream { 30 private: 31 // Do not implement. raw_ostream is noncopyable. 32 void operator=(const raw_ostream &); 33 raw_ostream(const raw_ostream &); 34 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. 39 /// 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). 45 /// 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. 49 /// 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 52 /// this buffer. 53 char *OutBufStart, *OutBufEnd, *OutBufCur; 54 55 enum BufferKind { 56 Unbuffered = 0, 57 InternalBuffer, 58 ExternalBuffer 59 } BufferMode; 60 61 public: 62 // color order matches ANSI escape sequence, don't change 63 enum Colors { 64 BLACK=0, 65 RED, 66 GREEN, 67 YELLOW, 68 BLUE, 69 MAGENTA, 70 CYAN, 71 WHITE, 72 SAVEDCOLOR 73 }; 74 75 explicit raw_ostream(bool unbuffered=false) 76 : BufferMode(unbuffered ? Unbuffered : InternalBuffer) { 77 // Start out ready to flush. 78 OutBufStart = OutBufEnd = OutBufCur = 0; 79 } 80 81 virtual ~raw_ostream(); 82 83 /// tell - Return the current offset with the file. tell()84 uint64_t tell() const { return current_pos() + GetNumBytesInBuffer(); } 85 86 //===--------------------------------------------------------------------===// 87 // Configuration Interface 88 //===--------------------------------------------------------------------===// 89 90 /// SetBuffered - Set the stream to be buffered, with an automatically 91 /// determined buffer size. 92 void SetBuffered(); 93 94 /// SetBufferSize - Set the stream to be buffered, using the 95 /// specified buffer size. SetBufferSize(size_t Size)96 void SetBufferSize(size_t Size) { 97 flush(); 98 SetBufferAndMode(new char[Size], Size, InternalBuffer); 99 } 100 GetBufferSize()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(); 106 107 // Otherwise just return the size of the allocated buffer. 108 return OutBufEnd - OutBufStart; 109 } 110 111 /// 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. SetUnbuffered()115 void SetUnbuffered() { 116 flush(); 117 SetBufferAndMode(0, 0, Unbuffered); 118 } 119 GetNumBytesInBuffer()120 size_t GetNumBytesInBuffer() const { 121 return OutBufCur - OutBufStart; 122 } 123 124 //===--------------------------------------------------------------------===// 125 // Data Output Interface 126 //===--------------------------------------------------------------------===// 127 flush()128 void flush() { 129 if (OutBufCur != OutBufStart) 130 flush_nonempty(); 131 } 132 133 raw_ostream &operator<<(char C) { 134 if (OutBufCur >= OutBufEnd) 135 return write(C); 136 *OutBufCur++ = C; 137 return *this; 138 } 139 140 raw_ostream &operator<<(unsigned char C) { 141 if (OutBufCur >= OutBufEnd) 142 return write(C); 143 *OutBufCur++ = C; 144 return *this; 145 } 146 147 raw_ostream &operator<<(signed char C) { 148 if (OutBufCur >= OutBufEnd) 149 return write(C); 150 *OutBufCur++ = C; 151 return *this; 152 } 153 154 raw_ostream &operator<<(StringRef Str) { 155 // Inline fast path, particularly for strings with a known length. 156 size_t Size = Str.size(); 157 158 // Make sure we can use the fast path. 159 if (OutBufCur+Size > OutBufEnd) 160 return write(Str.data(), Size); 161 162 memcpy(OutBufCur, Str.data(), Size); 163 OutBufCur += Size; 164 return *this; 165 } 166 167 raw_ostream &operator<<(const char *Str) { 168 // Inline fast path, particularly for constant strings where a sufficiently 169 // smart compiler will simplify strlen. 170 171 return this->operator<<(StringRef(Str)); 172 } 173 174 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()); 177 } 178 179 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)); 186 } 187 188 raw_ostream &operator<<(int N) { 189 return this->operator<<(static_cast<long>(N)); 190 } 191 192 raw_ostream &operator<<(double N); 193 194 /// write_hex - Output \arg N in hexadecimal, without any prefix or padding. 195 raw_ostream &write_hex(unsigned long long N); 196 197 /// write_escaped - Output \arg 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); 200 201 raw_ostream &write(unsigned char C); 202 raw_ostream &write(const char *Ptr, size_t Size); 203 204 // Formatted output, see the format() function in Support/Format.h. 205 raw_ostream &operator<<(const format_object_base &Fmt); 206 207 /// indent - Insert 'NumSpaces' spaces. 208 raw_ostream &indent(unsigned NumSpaces); 209 210 211 /// Changes the foreground color of text that will be output from this point 212 /// forward. 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, 219 bool Bold = false, 220 bool BG = false) { 221 return *this; 222 } 223 224 /// Resets the colors to terminal defaults. Call this when you are done 225 /// outputting colored text, or before program exit. resetColor()226 virtual raw_ostream &resetColor() { return *this; } 227 228 /// Reverses the forground and background colors. reverseColor()229 virtual raw_ostream &reverseColor() { return *this; } 230 231 /// This function determines if this stream is connected to a "tty" or 232 /// "console" window. That is, the output would be displayed to the user 233 /// rather than being put on a pipe or stored in a file. is_displayed()234 virtual bool is_displayed() const { return false; } 235 236 /// This function determines if this stream is displayed and supports colors. has_colors()237 virtual bool has_colors() const { return is_displayed(); } 238 239 //===--------------------------------------------------------------------===// 240 // Subclass Interface 241 //===--------------------------------------------------------------------===// 242 243 private: 244 /// write_impl - The is the piece of the class that is implemented 245 /// by subclasses. This writes the \args Size bytes starting at 246 /// \arg Ptr to the underlying stream. 247 /// 248 /// This function is guaranteed to only be called at a point at which it is 249 /// safe for the subclass to install a new buffer via SetBuffer. 250 /// 251 /// \arg Ptr - The start of the data to be written. For buffered streams this 252 /// is guaranteed to be the start of the buffer. 253 /// \arg Size - The number of bytes to be written. 254 /// 255 /// \invariant { Size > 0 } 256 virtual void write_impl(const char *Ptr, size_t Size) = 0; 257 258 // An out of line virtual method to provide a home for the class vtable. 259 virtual void handle(); 260 261 /// current_pos - Return the current position within the stream, not 262 /// counting the bytes currently in the buffer. 263 virtual uint64_t current_pos() const = 0; 264 265 protected: 266 /// SetBuffer - Use the provided buffer as the raw_ostream buffer. This is 267 /// intended for use only by subclasses which can arrange for the output to go 268 /// directly into the desired output buffer, instead of being copied on each 269 /// flush. SetBuffer(char * BufferStart,size_t Size)270 void SetBuffer(char *BufferStart, size_t Size) { 271 SetBufferAndMode(BufferStart, Size, ExternalBuffer); 272 } 273 274 /// preferred_buffer_size - Return an efficient buffer size for the 275 /// underlying output mechanism. 276 virtual size_t preferred_buffer_size() const; 277 278 /// getBufferStart - Return the beginning of the current stream buffer, or 0 279 /// if the stream is unbuffered. getBufferStart()280 const char *getBufferStart() const { return OutBufStart; } 281 282 //===--------------------------------------------------------------------===// 283 // Private Interface 284 //===--------------------------------------------------------------------===// 285 private: 286 /// SetBufferAndMode - Install the given buffer and mode. 287 void SetBufferAndMode(char *BufferStart, size_t Size, BufferKind Mode); 288 289 /// flush_nonempty - Flush the current buffer, which is known to be 290 /// non-empty. This outputs the currently buffered data and resets 291 /// the buffer to empty. 292 void flush_nonempty(); 293 294 /// copy_to_buffer - Copy data into the buffer. Size must not be 295 /// greater than the number of unused bytes in the buffer. 296 void copy_to_buffer(const char *Ptr, size_t Size); 297 }; 298 299 //===----------------------------------------------------------------------===// 300 // File Output Streams 301 //===----------------------------------------------------------------------===// 302 303 /// raw_fd_ostream - A raw_ostream that writes to a file descriptor. 304 /// 305 class raw_fd_ostream : public raw_ostream { 306 int FD; 307 bool ShouldClose; 308 309 /// Error This flag is true if an error of any kind has been detected. 310 /// 311 bool Error; 312 313 /// Controls whether the stream should attempt to use atomic writes, when 314 /// possible. 315 bool UseAtomicWrites; 316 317 uint64_t pos; 318 319 /// write_impl - See raw_ostream::write_impl. 320 virtual void write_impl(const char *Ptr, size_t Size); 321 322 /// current_pos - Return the current position within the stream, not 323 /// counting the bytes currently in the buffer. current_pos()324 virtual uint64_t current_pos() const { return pos; } 325 326 /// preferred_buffer_size - Determine an efficient buffer size. 327 virtual size_t preferred_buffer_size() const; 328 329 /// error_detected - Set the flag indicating that an output error has 330 /// been encountered. error_detected()331 void error_detected() { Error = true; } 332 333 public: 334 335 enum { 336 /// F_Excl - When opening a file, this flag makes raw_fd_ostream 337 /// report an error if the file already exists. 338 F_Excl = 1, 339 340 /// F_Append - When opening a file, if it already exists append to the 341 /// existing file instead of returning an error. This may not be specified 342 /// with F_Excl. 343 F_Append = 2, 344 345 /// F_Binary - The file should be opened in binary mode on platforms that 346 /// make this distinction. 347 F_Binary = 4 348 }; 349 350 /// raw_fd_ostream - Open the specified file for writing. If an error occurs, 351 /// information about the error is put into ErrorInfo, and the stream should 352 /// be immediately destroyed; the string will be empty if no error occurred. 353 /// This allows optional flags to control how the file will be opened. 354 /// 355 /// As a special case, if Filename is "-", then the stream will use 356 /// STDOUT_FILENO instead of opening a file. Note that it will still consider 357 /// itself to own the file descriptor. In particular, it will close the 358 /// file descriptor when it is done (this is necessary to detect 359 /// output errors). 360 raw_fd_ostream(const char *Filename, std::string &ErrorInfo, 361 unsigned Flags = 0); 362 363 /// raw_fd_ostream ctor - FD is the file descriptor that this writes to. If 364 /// ShouldClose is true, this closes the file when the stream is destroyed. 365 raw_fd_ostream(int fd, bool shouldClose, bool unbuffered=false); 366 367 ~raw_fd_ostream(); 368 369 /// close - Manually flush the stream and close the file. 370 /// Note that this does not call fsync. 371 void close(); 372 373 /// seek - Flushes the stream and repositions the underlying file descriptor 374 /// position to the offset specified from the beginning of the file. 375 uint64_t seek(uint64_t off); 376 377 /// SetUseAtomicWrite - Set the stream to attempt to use atomic writes for 378 /// individual output routines where possible. 379 /// 380 /// Note that because raw_ostream's are typically buffered, this flag is only 381 /// sensible when used on unbuffered streams which will flush their output 382 /// immediately. SetUseAtomicWrites(bool Value)383 void SetUseAtomicWrites(bool Value) { 384 UseAtomicWrites = Value; 385 } 386 387 virtual raw_ostream &changeColor(enum Colors colors, bool bold=false, 388 bool bg=false); 389 virtual raw_ostream &resetColor(); 390 391 virtual raw_ostream &reverseColor(); 392 393 virtual bool is_displayed() const; 394 395 virtual bool has_colors() const; 396 397 /// has_error - Return the value of the flag in this raw_fd_ostream indicating 398 /// whether an output error has been encountered. 399 /// This doesn't implicitly flush any pending output. Also, it doesn't 400 /// guarantee to detect all errors unless the stream has been closed. has_error()401 bool has_error() const { 402 return Error; 403 } 404 405 /// clear_error - Set the flag read by has_error() to false. If the error 406 /// flag is set at the time when this raw_ostream's destructor is called, 407 /// report_fatal_error is called to report the error. Use clear_error() 408 /// after handling the error to avoid this behavior. 409 /// 410 /// "Errors should never pass silently. 411 /// Unless explicitly silenced." 412 /// - from The Zen of Python, by Tim Peters 413 /// clear_error()414 void clear_error() { 415 Error = false; 416 } 417 }; 418 419 /// outs() - This returns a reference to a raw_ostream for standard output. 420 /// Use it like: outs() << "foo" << "bar"; 421 raw_ostream &outs(); 422 423 /// errs() - This returns a reference to a raw_ostream for standard error. 424 /// Use it like: errs() << "foo" << "bar"; 425 raw_ostream &errs(); 426 427 /// nulls() - This returns a reference to a raw_ostream which simply discards 428 /// output. 429 raw_ostream &nulls(); 430 431 //===----------------------------------------------------------------------===// 432 // Output Stream Adaptors 433 //===----------------------------------------------------------------------===// 434 435 /// raw_string_ostream - A raw_ostream that writes to an std::string. This is a 436 /// simple adaptor class. This class does not encounter output errors. 437 class raw_string_ostream : public raw_ostream { 438 std::string &OS; 439 440 /// write_impl - See raw_ostream::write_impl. 441 virtual void write_impl(const char *Ptr, size_t Size); 442 443 /// current_pos - Return the current position within the stream, not 444 /// counting the bytes currently in the buffer. current_pos()445 virtual uint64_t current_pos() const { return OS.size(); } 446 public: raw_string_ostream(std::string & O)447 explicit raw_string_ostream(std::string &O) : OS(O) {} 448 ~raw_string_ostream(); 449 450 /// str - Flushes the stream contents to the target string and returns 451 /// the string's reference. str()452 std::string& str() { 453 flush(); 454 return OS; 455 } 456 }; 457 458 /// raw_svector_ostream - A raw_ostream that writes to an SmallVector or 459 /// SmallString. This is a simple adaptor class. This class does not 460 /// encounter output errors. 461 class raw_svector_ostream : public raw_ostream { 462 SmallVectorImpl<char> &OS; 463 464 /// write_impl - See raw_ostream::write_impl. 465 virtual void write_impl(const char *Ptr, size_t Size); 466 467 /// current_pos - Return the current position within the stream, not 468 /// counting the bytes currently in the buffer. 469 virtual uint64_t current_pos() const; 470 public: 471 /// Construct a new raw_svector_ostream. 472 /// 473 /// \arg O - The vector to write to; this should generally have at least 128 474 /// bytes free to avoid any extraneous memory overhead. 475 explicit raw_svector_ostream(SmallVectorImpl<char> &O); 476 ~raw_svector_ostream(); 477 478 /// resync - This is called when the SmallVector we're appending to is changed 479 /// outside of the raw_svector_ostream's control. It is only safe to do this 480 /// if the raw_svector_ostream has previously been flushed. 481 void resync(); 482 483 /// str - Flushes the stream contents to the target vector and return a 484 /// StringRef for the vector contents. 485 StringRef str(); 486 }; 487 488 /// raw_null_ostream - A raw_ostream that discards all output. 489 class raw_null_ostream : public raw_ostream { 490 /// write_impl - See raw_ostream::write_impl. 491 virtual void write_impl(const char *Ptr, size_t size); 492 493 /// current_pos - Return the current position within the stream, not 494 /// counting the bytes currently in the buffer. 495 virtual uint64_t current_pos() const; 496 497 public: raw_null_ostream()498 explicit raw_null_ostream() {} 499 ~raw_null_ostream(); 500 }; 501 502 } // end llvm namespace 503 504 #endif 505