1 //===--- raw_ostream.cpp - Implement the raw_ostream classes --------------===// 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 implements support for bulk buffered stream output. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #include "llvm/Support/raw_ostream.h" 15 #include "llvm/ADT/STLExtras.h" 16 #include "llvm/ADT/SmallVector.h" 17 #include "llvm/ADT/StringExtras.h" 18 #include "llvm/Config/config.h" 19 #include "llvm/Support/Compiler.h" 20 #include "llvm/Support/ErrorHandling.h" 21 #include "llvm/Support/Format.h" 22 #include "llvm/Support/Process.h" 23 #include "llvm/Support/Program.h" 24 #include "llvm/Support/system_error.h" 25 #include <cctype> 26 #include <cerrno> 27 #include <sys/stat.h> 28 #include <sys/types.h> 29 30 #if defined(HAVE_UNISTD_H) 31 # include <unistd.h> 32 #endif 33 #if defined(HAVE_FCNTL_H) 34 # include <fcntl.h> 35 #endif 36 #if defined(HAVE_SYS_UIO_H) && defined(HAVE_WRITEV) 37 # include <sys/uio.h> 38 #endif 39 40 #if defined(__CYGWIN__) 41 #include <io.h> 42 #endif 43 44 #if defined(_MSC_VER) 45 #include <io.h> 46 #include <fcntl.h> 47 #ifndef STDIN_FILENO 48 # define STDIN_FILENO 0 49 #endif 50 #ifndef STDOUT_FILENO 51 # define STDOUT_FILENO 1 52 #endif 53 #ifndef STDERR_FILENO 54 # define STDERR_FILENO 2 55 #endif 56 #endif 57 58 using namespace llvm; 59 60 raw_ostream::~raw_ostream() { 61 // raw_ostream's subclasses should take care to flush the buffer 62 // in their destructors. 63 assert(OutBufCur == OutBufStart && 64 "raw_ostream destructor called with non-empty buffer!"); 65 66 if (BufferMode == InternalBuffer) 67 delete [] OutBufStart; 68 } 69 70 // An out of line virtual method to provide a home for the class vtable. 71 void raw_ostream::handle() {} 72 73 size_t raw_ostream::preferred_buffer_size() const { 74 // BUFSIZ is intended to be a reasonable default. 75 return BUFSIZ; 76 } 77 78 void raw_ostream::SetBuffered() { 79 // Ask the subclass to determine an appropriate buffer size. 80 if (size_t Size = preferred_buffer_size()) 81 SetBufferSize(Size); 82 else 83 // It may return 0, meaning this stream should be unbuffered. 84 SetUnbuffered(); 85 } 86 87 void raw_ostream::SetBufferAndMode(char *BufferStart, size_t Size, 88 BufferKind Mode) { 89 assert(((Mode == Unbuffered && BufferStart == 0 && Size == 0) || 90 (Mode != Unbuffered && BufferStart && Size)) && 91 "stream must be unbuffered or have at least one byte"); 92 // Make sure the current buffer is free of content (we can't flush here; the 93 // child buffer management logic will be in write_impl). 94 assert(GetNumBytesInBuffer() == 0 && "Current buffer is non-empty!"); 95 96 if (BufferMode == InternalBuffer) 97 delete [] OutBufStart; 98 OutBufStart = BufferStart; 99 OutBufEnd = OutBufStart+Size; 100 OutBufCur = OutBufStart; 101 BufferMode = Mode; 102 103 assert(OutBufStart <= OutBufEnd && "Invalid size!"); 104 } 105 106 raw_ostream &raw_ostream::operator<<(unsigned long N) { 107 // Zero is a special case. 108 if (N == 0) 109 return *this << '0'; 110 111 char NumberBuffer[20]; 112 char *EndPtr = NumberBuffer+sizeof(NumberBuffer); 113 char *CurPtr = EndPtr; 114 115 while (N) { 116 *--CurPtr = '0' + char(N % 10); 117 N /= 10; 118 } 119 return write(CurPtr, EndPtr-CurPtr); 120 } 121 122 raw_ostream &raw_ostream::operator<<(long N) { 123 if (N < 0) { 124 *this << '-'; 125 // Avoid undefined behavior on LONG_MIN with a cast. 126 N = -(unsigned long)N; 127 } 128 129 return this->operator<<(static_cast<unsigned long>(N)); 130 } 131 132 raw_ostream &raw_ostream::operator<<(unsigned long long N) { 133 // Output using 32-bit div/mod when possible. 134 if (N == static_cast<unsigned long>(N)) 135 return this->operator<<(static_cast<unsigned long>(N)); 136 137 char NumberBuffer[20]; 138 char *EndPtr = NumberBuffer+sizeof(NumberBuffer); 139 char *CurPtr = EndPtr; 140 141 while (N) { 142 *--CurPtr = '0' + char(N % 10); 143 N /= 10; 144 } 145 return write(CurPtr, EndPtr-CurPtr); 146 } 147 148 raw_ostream &raw_ostream::operator<<(long long N) { 149 if (N < 0) { 150 *this << '-'; 151 // Avoid undefined behavior on INT64_MIN with a cast. 152 N = -(unsigned long long)N; 153 } 154 155 return this->operator<<(static_cast<unsigned long long>(N)); 156 } 157 158 raw_ostream &raw_ostream::write_hex(unsigned long long N) { 159 // Zero is a special case. 160 if (N == 0) 161 return *this << '0'; 162 163 char NumberBuffer[20]; 164 char *EndPtr = NumberBuffer+sizeof(NumberBuffer); 165 char *CurPtr = EndPtr; 166 167 while (N) { 168 uintptr_t x = N % 16; 169 *--CurPtr = (x < 10 ? '0' + x : 'a' + x - 10); 170 N /= 16; 171 } 172 173 return write(CurPtr, EndPtr-CurPtr); 174 } 175 176 raw_ostream &raw_ostream::write_escaped(StringRef Str, 177 bool UseHexEscapes) { 178 for (unsigned i = 0, e = Str.size(); i != e; ++i) { 179 unsigned char c = Str[i]; 180 181 switch (c) { 182 case '\\': 183 *this << '\\' << '\\'; 184 break; 185 case '\t': 186 *this << '\\' << 't'; 187 break; 188 case '\n': 189 *this << '\\' << 'n'; 190 break; 191 case '"': 192 *this << '\\' << '"'; 193 break; 194 default: 195 if (std::isprint(c)) { 196 *this << c; 197 break; 198 } 199 200 // Write out the escaped representation. 201 if (UseHexEscapes) { 202 *this << '\\' << 'x'; 203 *this << hexdigit((c >> 4 & 0xF)); 204 *this << hexdigit((c >> 0) & 0xF); 205 } else { 206 // Always use a full 3-character octal escape. 207 *this << '\\'; 208 *this << char('0' + ((c >> 6) & 7)); 209 *this << char('0' + ((c >> 3) & 7)); 210 *this << char('0' + ((c >> 0) & 7)); 211 } 212 } 213 } 214 215 return *this; 216 } 217 218 raw_ostream &raw_ostream::operator<<(const void *P) { 219 *this << '0' << 'x'; 220 221 return write_hex((uintptr_t) P); 222 } 223 224 raw_ostream &raw_ostream::operator<<(double N) { 225 #ifdef _WIN32 226 // On MSVCRT and compatible, output of %e is incompatible to Posix 227 // by default. Number of exponent digits should be at least 2. "%+03d" 228 // FIXME: Implement our formatter to here or Support/Format.h! 229 int fpcl = _fpclass(N); 230 231 // negative zero 232 if (fpcl == _FPCLASS_NZ) 233 return *this << "-0.000000e+00"; 234 235 char buf[16]; 236 unsigned len; 237 len = snprintf(buf, sizeof(buf), "%e", N); 238 if (len <= sizeof(buf) - 2) { 239 if (len >= 5 && buf[len - 5] == 'e' && buf[len - 3] == '0') { 240 int cs = buf[len - 4]; 241 if (cs == '+' || cs == '-') { 242 int c1 = buf[len - 2]; 243 int c0 = buf[len - 1]; 244 if (isdigit(static_cast<unsigned char>(c1)) && 245 isdigit(static_cast<unsigned char>(c0))) { 246 // Trim leading '0': "...e+012" -> "...e+12\0" 247 buf[len - 3] = c1; 248 buf[len - 2] = c0; 249 buf[--len] = 0; 250 } 251 } 252 } 253 return this->operator<<(buf); 254 } 255 #endif 256 return this->operator<<(format("%e", N)); 257 } 258 259 260 261 void raw_ostream::flush_nonempty() { 262 assert(OutBufCur > OutBufStart && "Invalid call to flush_nonempty."); 263 size_t Length = OutBufCur - OutBufStart; 264 OutBufCur = OutBufStart; 265 write_impl(OutBufStart, Length); 266 } 267 268 raw_ostream &raw_ostream::write(unsigned char C) { 269 // Group exceptional cases into a single branch. 270 if (LLVM_UNLIKELY(OutBufCur >= OutBufEnd)) { 271 if (LLVM_UNLIKELY(!OutBufStart)) { 272 if (BufferMode == Unbuffered) { 273 write_impl(reinterpret_cast<char*>(&C), 1); 274 return *this; 275 } 276 // Set up a buffer and start over. 277 SetBuffered(); 278 return write(C); 279 } 280 281 flush_nonempty(); 282 } 283 284 *OutBufCur++ = C; 285 return *this; 286 } 287 288 raw_ostream &raw_ostream::write(const char *Ptr, size_t Size) { 289 // Group exceptional cases into a single branch. 290 if (LLVM_UNLIKELY(size_t(OutBufEnd - OutBufCur) < Size)) { 291 if (LLVM_UNLIKELY(!OutBufStart)) { 292 if (BufferMode == Unbuffered) { 293 write_impl(Ptr, Size); 294 return *this; 295 } 296 // Set up a buffer and start over. 297 SetBuffered(); 298 return write(Ptr, Size); 299 } 300 301 size_t NumBytes = OutBufEnd - OutBufCur; 302 303 // If the buffer is empty at this point we have a string that is larger 304 // than the buffer. Directly write the chunk that is a multiple of the 305 // preferred buffer size and put the remainder in the buffer. 306 if (LLVM_UNLIKELY(OutBufCur == OutBufStart)) { 307 size_t BytesToWrite = Size - (Size % NumBytes); 308 write_impl(Ptr, BytesToWrite); 309 size_t BytesRemaining = Size - BytesToWrite; 310 if (BytesRemaining > size_t(OutBufEnd - OutBufCur)) { 311 // Too much left over to copy into our buffer. 312 return write(Ptr + BytesToWrite, BytesRemaining); 313 } 314 copy_to_buffer(Ptr + BytesToWrite, BytesRemaining); 315 return *this; 316 } 317 318 // We don't have enough space in the buffer to fit the string in. Insert as 319 // much as possible, flush and start over with the remainder. 320 copy_to_buffer(Ptr, NumBytes); 321 flush_nonempty(); 322 return write(Ptr + NumBytes, Size - NumBytes); 323 } 324 325 copy_to_buffer(Ptr, Size); 326 327 return *this; 328 } 329 330 void raw_ostream::copy_to_buffer(const char *Ptr, size_t Size) { 331 assert(Size <= size_t(OutBufEnd - OutBufCur) && "Buffer overrun!"); 332 333 // Handle short strings specially, memcpy isn't very good at very short 334 // strings. 335 switch (Size) { 336 case 4: OutBufCur[3] = Ptr[3]; // FALL THROUGH 337 case 3: OutBufCur[2] = Ptr[2]; // FALL THROUGH 338 case 2: OutBufCur[1] = Ptr[1]; // FALL THROUGH 339 case 1: OutBufCur[0] = Ptr[0]; // FALL THROUGH 340 case 0: break; 341 default: 342 memcpy(OutBufCur, Ptr, Size); 343 break; 344 } 345 346 OutBufCur += Size; 347 } 348 349 // Formatted output. 350 raw_ostream &raw_ostream::operator<<(const format_object_base &Fmt) { 351 // If we have more than a few bytes left in our output buffer, try 352 // formatting directly onto its end. 353 size_t NextBufferSize = 127; 354 size_t BufferBytesLeft = OutBufEnd - OutBufCur; 355 if (BufferBytesLeft > 3) { 356 size_t BytesUsed = Fmt.print(OutBufCur, BufferBytesLeft); 357 358 // Common case is that we have plenty of space. 359 if (BytesUsed <= BufferBytesLeft) { 360 OutBufCur += BytesUsed; 361 return *this; 362 } 363 364 // Otherwise, we overflowed and the return value tells us the size to try 365 // again with. 366 NextBufferSize = BytesUsed; 367 } 368 369 // If we got here, we didn't have enough space in the output buffer for the 370 // string. Try printing into a SmallVector that is resized to have enough 371 // space. Iterate until we win. 372 SmallVector<char, 128> V; 373 374 while (1) { 375 V.resize(NextBufferSize); 376 377 // Try formatting into the SmallVector. 378 size_t BytesUsed = Fmt.print(V.data(), NextBufferSize); 379 380 // If BytesUsed fit into the vector, we win. 381 if (BytesUsed <= NextBufferSize) 382 return write(V.data(), BytesUsed); 383 384 // Otherwise, try again with a new size. 385 assert(BytesUsed > NextBufferSize && "Didn't grow buffer!?"); 386 NextBufferSize = BytesUsed; 387 } 388 } 389 390 /// indent - Insert 'NumSpaces' spaces. 391 raw_ostream &raw_ostream::indent(unsigned NumSpaces) { 392 static const char Spaces[] = " " 393 " " 394 " "; 395 396 // Usually the indentation is small, handle it with a fastpath. 397 if (NumSpaces < array_lengthof(Spaces)) 398 return write(Spaces, NumSpaces); 399 400 while (NumSpaces) { 401 unsigned NumToWrite = std::min(NumSpaces, 402 (unsigned)array_lengthof(Spaces)-1); 403 write(Spaces, NumToWrite); 404 NumSpaces -= NumToWrite; 405 } 406 return *this; 407 } 408 409 410 //===----------------------------------------------------------------------===// 411 // Formatted Output 412 //===----------------------------------------------------------------------===// 413 414 // Out of line virtual method. 415 void format_object_base::home() { 416 } 417 418 //===----------------------------------------------------------------------===// 419 // raw_fd_ostream 420 //===----------------------------------------------------------------------===// 421 422 /// raw_fd_ostream - Open the specified file for writing. If an error 423 /// occurs, information about the error is put into ErrorInfo, and the 424 /// stream should be immediately destroyed; the string will be empty 425 /// if no error occurred. 426 raw_fd_ostream::raw_fd_ostream(const char *Filename, std::string &ErrorInfo, 427 unsigned Flags) 428 : Error(false), UseAtomicWrites(false), pos(0) 429 { 430 assert(Filename != 0 && "Filename is null"); 431 // Verify that we don't have both "append" and "excl". 432 assert((!(Flags & F_Excl) || !(Flags & F_Append)) && 433 "Cannot specify both 'excl' and 'append' file creation flags!"); 434 435 ErrorInfo.clear(); 436 437 // Handle "-" as stdout. Note that when we do this, we consider ourself 438 // the owner of stdout. This means that we can do things like close the 439 // file descriptor when we're done and set the "binary" flag globally. 440 if (Filename[0] == '-' && Filename[1] == 0) { 441 FD = STDOUT_FILENO; 442 // If user requested binary then put stdout into binary mode if 443 // possible. 444 if (Flags & F_Binary) 445 sys::Program::ChangeStdoutToBinary(); 446 // Close stdout when we're done, to detect any output errors. 447 ShouldClose = true; 448 return; 449 } 450 451 int OpenFlags = O_WRONLY|O_CREAT; 452 #ifdef O_BINARY 453 if (Flags & F_Binary) 454 OpenFlags |= O_BINARY; 455 #endif 456 457 if (Flags & F_Append) 458 OpenFlags |= O_APPEND; 459 else 460 OpenFlags |= O_TRUNC; 461 if (Flags & F_Excl) 462 OpenFlags |= O_EXCL; 463 464 while ((FD = open(Filename, OpenFlags, 0664)) < 0) { 465 if (errno != EINTR) { 466 ErrorInfo = "Error opening output file '" + std::string(Filename) + "'"; 467 ShouldClose = false; 468 return; 469 } 470 } 471 472 // Ok, we successfully opened the file, so it'll need to be closed. 473 ShouldClose = true; 474 } 475 476 /// raw_fd_ostream ctor - FD is the file descriptor that this writes to. If 477 /// ShouldClose is true, this closes the file when the stream is destroyed. 478 raw_fd_ostream::raw_fd_ostream(int fd, bool shouldClose, bool unbuffered) 479 : raw_ostream(unbuffered), FD(fd), 480 ShouldClose(shouldClose), Error(false), UseAtomicWrites(false) { 481 #ifdef O_BINARY 482 // Setting STDOUT and STDERR to binary mode is necessary in Win32 483 // to avoid undesirable linefeed conversion. 484 if (fd == STDOUT_FILENO || fd == STDERR_FILENO) 485 setmode(fd, O_BINARY); 486 #endif 487 488 // Get the starting position. 489 off_t loc = ::lseek(FD, 0, SEEK_CUR); 490 if (loc == (off_t)-1) 491 pos = 0; 492 else 493 pos = static_cast<uint64_t>(loc); 494 } 495 496 raw_fd_ostream::~raw_fd_ostream() { 497 if (FD >= 0) { 498 flush(); 499 if (ShouldClose) 500 while (::close(FD) != 0) 501 if (errno != EINTR) { 502 error_detected(); 503 break; 504 } 505 } 506 507 #ifdef __MINGW32__ 508 // On mingw, global dtors should not call exit(). 509 // report_fatal_error() invokes exit(). We know report_fatal_error() 510 // might not write messages to stderr when any errors were detected 511 // on FD == 2. 512 if (FD == 2) return; 513 #endif 514 515 // If there are any pending errors, report them now. Clients wishing 516 // to avoid report_fatal_error calls should check for errors with 517 // has_error() and clear the error flag with clear_error() before 518 // destructing raw_ostream objects which may have errors. 519 if (has_error()) 520 report_fatal_error("IO failure on output stream."); 521 } 522 523 524 void raw_fd_ostream::write_impl(const char *Ptr, size_t Size) { 525 assert(FD >= 0 && "File already closed."); 526 pos += Size; 527 528 do { 529 ssize_t ret; 530 531 // Check whether we should attempt to use atomic writes. 532 if (LLVM_LIKELY(!UseAtomicWrites)) { 533 ret = ::write(FD, Ptr, Size); 534 } else { 535 // Use ::writev() where available. 536 #if defined(HAVE_WRITEV) 537 const void *Addr = static_cast<const void *>(Ptr); 538 struct iovec IOV = {const_cast<void *>(Addr), Size }; 539 ret = ::writev(FD, &IOV, 1); 540 #else 541 ret = ::write(FD, Ptr, Size); 542 #endif 543 } 544 545 if (ret < 0) { 546 // If it's a recoverable error, swallow it and retry the write. 547 // 548 // Ideally we wouldn't ever see EAGAIN or EWOULDBLOCK here, since 549 // raw_ostream isn't designed to do non-blocking I/O. However, some 550 // programs, such as old versions of bjam, have mistakenly used 551 // O_NONBLOCK. For compatibility, emulate blocking semantics by 552 // spinning until the write succeeds. If you don't want spinning, 553 // don't use O_NONBLOCK file descriptors with raw_ostream. 554 if (errno == EINTR || errno == EAGAIN 555 #ifdef EWOULDBLOCK 556 || errno == EWOULDBLOCK 557 #endif 558 ) 559 continue; 560 561 // Otherwise it's a non-recoverable error. Note it and quit. 562 error_detected(); 563 break; 564 } 565 566 // The write may have written some or all of the data. Update the 567 // size and buffer pointer to reflect the remainder that needs 568 // to be written. If there are no bytes left, we're done. 569 Ptr += ret; 570 Size -= ret; 571 } while (Size > 0); 572 } 573 574 void raw_fd_ostream::close() { 575 assert(ShouldClose); 576 ShouldClose = false; 577 flush(); 578 while (::close(FD) != 0) 579 if (errno != EINTR) { 580 error_detected(); 581 break; 582 } 583 FD = -1; 584 } 585 586 uint64_t raw_fd_ostream::seek(uint64_t off) { 587 flush(); 588 pos = ::lseek(FD, off, SEEK_SET); 589 if (pos != off) 590 error_detected(); 591 return pos; 592 } 593 594 size_t raw_fd_ostream::preferred_buffer_size() const { 595 #if !defined(_MSC_VER) && !defined(__MINGW32__) && !defined(__minix) 596 // Windows and Minix have no st_blksize. 597 assert(FD >= 0 && "File not yet open!"); 598 struct stat statbuf; 599 if (fstat(FD, &statbuf) != 0) 600 return 0; 601 602 // If this is a terminal, don't use buffering. Line buffering 603 // would be a more traditional thing to do, but it's not worth 604 // the complexity. 605 if (S_ISCHR(statbuf.st_mode) && isatty(FD)) 606 return 0; 607 // Return the preferred block size. 608 return statbuf.st_blksize; 609 #else 610 return raw_ostream::preferred_buffer_size(); 611 #endif 612 } 613 614 raw_ostream &raw_fd_ostream::changeColor(enum Colors colors, bool bold, 615 bool bg) { 616 if (sys::Process::ColorNeedsFlush()) 617 flush(); 618 const char *colorcode = 619 (colors == SAVEDCOLOR) ? sys::Process::OutputBold(bg) 620 : sys::Process::OutputColor(colors, bold, bg); 621 if (colorcode) { 622 size_t len = strlen(colorcode); 623 write(colorcode, len); 624 // don't account colors towards output characters 625 pos -= len; 626 } 627 return *this; 628 } 629 630 raw_ostream &raw_fd_ostream::resetColor() { 631 if (sys::Process::ColorNeedsFlush()) 632 flush(); 633 const char *colorcode = sys::Process::ResetColor(); 634 if (colorcode) { 635 size_t len = strlen(colorcode); 636 write(colorcode, len); 637 // don't account colors towards output characters 638 pos -= len; 639 } 640 return *this; 641 } 642 643 raw_ostream &raw_fd_ostream::reverseColor() { 644 if (sys::Process::ColorNeedsFlush()) 645 flush(); 646 const char *colorcode = sys::Process::OutputReverse(); 647 if (colorcode) { 648 size_t len = strlen(colorcode); 649 write(colorcode, len); 650 // don't account colors towards output characters 651 pos -= len; 652 } 653 return *this; 654 } 655 656 bool raw_fd_ostream::is_displayed() const { 657 return sys::Process::FileDescriptorIsDisplayed(FD); 658 } 659 660 bool raw_fd_ostream::has_colors() const { 661 return sys::Process::FileDescriptorHasColors(FD); 662 } 663 664 //===----------------------------------------------------------------------===// 665 // outs(), errs(), nulls() 666 //===----------------------------------------------------------------------===// 667 668 /// outs() - This returns a reference to a raw_ostream for standard output. 669 /// Use it like: outs() << "foo" << "bar"; 670 raw_ostream &llvm::outs() { 671 // Set buffer settings to model stdout behavior. 672 // Delete the file descriptor when the program exists, forcing error 673 // detection. If you don't want this behavior, don't use outs(). 674 static raw_fd_ostream S(STDOUT_FILENO, true); 675 return S; 676 } 677 678 /// errs() - This returns a reference to a raw_ostream for standard error. 679 /// Use it like: errs() << "foo" << "bar"; 680 raw_ostream &llvm::errs() { 681 // Set standard error to be unbuffered by default. 682 static raw_fd_ostream S(STDERR_FILENO, false, true); 683 return S; 684 } 685 686 /// nulls() - This returns a reference to a raw_ostream which discards output. 687 raw_ostream &llvm::nulls() { 688 static raw_null_ostream S; 689 return S; 690 } 691 692 693 //===----------------------------------------------------------------------===// 694 // raw_string_ostream 695 //===----------------------------------------------------------------------===// 696 697 raw_string_ostream::~raw_string_ostream() { 698 flush(); 699 } 700 701 void raw_string_ostream::write_impl(const char *Ptr, size_t Size) { 702 OS.append(Ptr, Size); 703 } 704 705 //===----------------------------------------------------------------------===// 706 // raw_svector_ostream 707 //===----------------------------------------------------------------------===// 708 709 // The raw_svector_ostream implementation uses the SmallVector itself as the 710 // buffer for the raw_ostream. We guarantee that the raw_ostream buffer is 711 // always pointing past the end of the vector, but within the vector 712 // capacity. This allows raw_ostream to write directly into the correct place, 713 // and we only need to set the vector size when the data is flushed. 714 715 raw_svector_ostream::raw_svector_ostream(SmallVectorImpl<char> &O) : OS(O) { 716 // Set up the initial external buffer. We make sure that the buffer has at 717 // least 128 bytes free; raw_ostream itself only requires 64, but we want to 718 // make sure that we don't grow the buffer unnecessarily on destruction (when 719 // the data is flushed). See the FIXME below. 720 OS.reserve(OS.size() + 128); 721 SetBuffer(OS.end(), OS.capacity() - OS.size()); 722 } 723 724 raw_svector_ostream::~raw_svector_ostream() { 725 // FIXME: Prevent resizing during this flush(). 726 flush(); 727 } 728 729 /// resync - This is called when the SmallVector we're appending to is changed 730 /// outside of the raw_svector_ostream's control. It is only safe to do this 731 /// if the raw_svector_ostream has previously been flushed. 732 void raw_svector_ostream::resync() { 733 assert(GetNumBytesInBuffer() == 0 && "Didn't flush before mutating vector"); 734 735 if (OS.capacity() - OS.size() < 64) 736 OS.reserve(OS.capacity() * 2); 737 SetBuffer(OS.end(), OS.capacity() - OS.size()); 738 } 739 740 void raw_svector_ostream::write_impl(const char *Ptr, size_t Size) { 741 // If we're writing bytes from the end of the buffer into the smallvector, we 742 // don't need to copy the bytes, just commit the bytes because they are 743 // already in the right place. 744 if (Ptr == OS.end()) { 745 assert(OS.size() + Size <= OS.capacity() && "Invalid write_impl() call!"); 746 OS.set_size(OS.size() + Size); 747 } else { 748 assert(GetNumBytesInBuffer() == 0 && 749 "Should be writing from buffer if some bytes in it"); 750 // Otherwise, do copy the bytes. 751 OS.append(Ptr, Ptr+Size); 752 } 753 754 // Grow the vector if necessary. 755 if (OS.capacity() - OS.size() < 64) 756 OS.reserve(OS.capacity() * 2); 757 758 // Update the buffer position. 759 SetBuffer(OS.end(), OS.capacity() - OS.size()); 760 } 761 762 uint64_t raw_svector_ostream::current_pos() const { 763 return OS.size(); 764 } 765 766 StringRef raw_svector_ostream::str() { 767 flush(); 768 return StringRef(OS.begin(), OS.size()); 769 } 770 771 //===----------------------------------------------------------------------===// 772 // raw_null_ostream 773 //===----------------------------------------------------------------------===// 774 775 raw_null_ostream::~raw_null_ostream() { 776 #ifndef NDEBUG 777 // ~raw_ostream asserts that the buffer is empty. This isn't necessary 778 // with raw_null_ostream, but it's better to have raw_null_ostream follow 779 // the rules than to change the rules just for raw_null_ostream. 780 flush(); 781 #endif 782 } 783 784 void raw_null_ostream::write_impl(const char *Ptr, size_t Size) { 785 } 786 787 uint64_t raw_null_ostream::current_pos() const { 788 return 0; 789 } 790