llvm-6502/include/llvm/Support/raw_ostream.h
Alp Toker 8dd8d5c2b2 Revert "Introduce a string_ostream string builder facilty"
Temporarily back out commits r211749, r211752 and r211754.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@211814 91177308-0d34-0410-b5e6-96231b3b80d8
2014-06-26 22:52:05 +00:00

499 lines
17 KiB
C++

//===--- raw_ostream.h - Raw output stream ----------------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines the raw_ostream class.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_SUPPORT_RAW_OSTREAM_H
#define LLVM_SUPPORT_RAW_OSTREAM_H
#include "llvm/ADT/StringRef.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/DataTypes.h"
namespace llvm {
class format_object_base;
template <typename T>
class SmallVectorImpl;
namespace sys {
namespace fs {
enum OpenFlags : unsigned;
}
}
/// raw_ostream - This class implements an extremely fast bulk output stream
/// that can *only* output to a stream. It does not support seeking, reopening,
/// rewinding, line buffered disciplines etc. It is a simple buffer that outputs
/// a chunk at a time.
class raw_ostream {
private:
void operator=(const raw_ostream &) LLVM_DELETED_FUNCTION;
raw_ostream(const raw_ostream &) LLVM_DELETED_FUNCTION;
/// The buffer is handled in such a way that the buffer is
/// uninitialized, unbuffered, or out of space when OutBufCur >=
/// OutBufEnd. Thus a single comparison suffices to determine if we
/// need to take the slow path to write a single character.
///
/// The buffer is in one of three states:
/// 1. Unbuffered (BufferMode == Unbuffered)
/// 1. Uninitialized (BufferMode != Unbuffered && OutBufStart == 0).
/// 2. Buffered (BufferMode != Unbuffered && OutBufStart != 0 &&
/// OutBufEnd - OutBufStart >= 1).
///
/// If buffered, then the raw_ostream owns the buffer if (BufferMode ==
/// InternalBuffer); otherwise the buffer has been set via SetBuffer and is
/// managed by the subclass.
///
/// If a subclass installs an external buffer using SetBuffer then it can wait
/// for a \see write_impl() call to handle the data which has been put into
/// this buffer.
char *OutBufStart, *OutBufEnd, *OutBufCur;
enum BufferKind {
Unbuffered = 0,
InternalBuffer,
ExternalBuffer
} BufferMode;
public:
// color order matches ANSI escape sequence, don't change
enum Colors {
BLACK=0,
RED,
GREEN,
YELLOW,
BLUE,
MAGENTA,
CYAN,
WHITE,
SAVEDCOLOR
};
explicit raw_ostream(bool unbuffered=false)
: BufferMode(unbuffered ? Unbuffered : InternalBuffer) {
// Start out ready to flush.
OutBufStart = OutBufEnd = OutBufCur = nullptr;
}
virtual ~raw_ostream();
/// tell - Return the current offset with the file.
uint64_t tell() const { return current_pos() + GetNumBytesInBuffer(); }
//===--------------------------------------------------------------------===//
// Configuration Interface
//===--------------------------------------------------------------------===//
/// SetBuffered - Set the stream to be buffered, with an automatically
/// determined buffer size.
void SetBuffered();
/// SetBufferSize - Set the stream to be buffered, using the
/// specified buffer size.
void SetBufferSize(size_t Size) {
flush();
SetBufferAndMode(new char[Size], Size, InternalBuffer);
}
size_t GetBufferSize() const {
// If we're supposed to be buffered but haven't actually gotten around
// to allocating the buffer yet, return the value that would be used.
if (BufferMode != Unbuffered && OutBufStart == nullptr)
return preferred_buffer_size();
// Otherwise just return the size of the allocated buffer.
return OutBufEnd - OutBufStart;
}
/// SetUnbuffered - Set the stream to be unbuffered. When
/// unbuffered, the stream will flush after every write. This routine
/// will also flush the buffer immediately when the stream is being
/// set to unbuffered.
void SetUnbuffered() {
flush();
SetBufferAndMode(nullptr, 0, Unbuffered);
}
size_t GetNumBytesInBuffer() const {
return OutBufCur - OutBufStart;
}
//===--------------------------------------------------------------------===//
// Data Output Interface
//===--------------------------------------------------------------------===//
void flush() {
if (OutBufCur != OutBufStart)
flush_nonempty();
}
raw_ostream &operator<<(char C) {
if (OutBufCur >= OutBufEnd)
return write(C);
*OutBufCur++ = C;
return *this;
}
raw_ostream &operator<<(unsigned char C) {
if (OutBufCur >= OutBufEnd)
return write(C);
*OutBufCur++ = C;
return *this;
}
raw_ostream &operator<<(signed char C) {
if (OutBufCur >= OutBufEnd)
return write(C);
*OutBufCur++ = C;
return *this;
}
raw_ostream &operator<<(StringRef Str) {
// Inline fast path, particularly for strings with a known length.
size_t Size = Str.size();
// Make sure we can use the fast path.
if (Size > (size_t)(OutBufEnd - OutBufCur))
return write(Str.data(), Size);
memcpy(OutBufCur, Str.data(), Size);
OutBufCur += Size;
return *this;
}
raw_ostream &operator<<(const char *Str) {
// Inline fast path, particularly for constant strings where a sufficiently
// smart compiler will simplify strlen.
return this->operator<<(StringRef(Str));
}
raw_ostream &operator<<(const std::string &Str) {
// Avoid the fast path, it would only increase code size for a marginal win.
return write(Str.data(), Str.length());
}
raw_ostream &operator<<(unsigned long N);
raw_ostream &operator<<(long N);
raw_ostream &operator<<(unsigned long long N);
raw_ostream &operator<<(long long N);
raw_ostream &operator<<(const void *P);
raw_ostream &operator<<(unsigned int N) {
return this->operator<<(static_cast<unsigned long>(N));
}
raw_ostream &operator<<(int N) {
return this->operator<<(static_cast<long>(N));
}
raw_ostream &operator<<(double N);
/// write_hex - Output \p N in hexadecimal, without any prefix or padding.
raw_ostream &write_hex(unsigned long long N);
/// write_escaped - Output \p Str, turning '\\', '\t', '\n', '"', and
/// anything that doesn't satisfy std::isprint into an escape sequence.
raw_ostream &write_escaped(StringRef Str, bool UseHexEscapes = false);
raw_ostream &write(unsigned char C);
raw_ostream &write(const char *Ptr, size_t Size);
// Formatted output, see the format() function in Support/Format.h.
raw_ostream &operator<<(const format_object_base &Fmt);
/// indent - Insert 'NumSpaces' spaces.
raw_ostream &indent(unsigned NumSpaces);
/// Changes the foreground color of text that will be output from this point
/// forward.
/// @param Color ANSI color to use, the special SAVEDCOLOR can be used to
/// change only the bold attribute, and keep colors untouched
/// @param Bold bold/brighter text, default false
/// @param BG if true change the background, default: change foreground
/// @returns itself so it can be used within << invocations
virtual raw_ostream &changeColor(enum Colors Color,
bool Bold = false,
bool BG = false) {
(void)Color;
(void)Bold;
(void)BG;
return *this;
}
/// Resets the colors to terminal defaults. Call this when you are done
/// outputting colored text, or before program exit.
virtual raw_ostream &resetColor() { return *this; }
/// Reverses the forground and background colors.
virtual raw_ostream &reverseColor() { return *this; }
/// This function determines if this stream is connected to a "tty" or
/// "console" window. That is, the output would be displayed to the user
/// rather than being put on a pipe or stored in a file.
virtual bool is_displayed() const { return false; }
/// This function determines if this stream is displayed and supports colors.
virtual bool has_colors() const { return is_displayed(); }
//===--------------------------------------------------------------------===//
// Subclass Interface
//===--------------------------------------------------------------------===//
private:
/// write_impl - The is the piece of the class that is implemented
/// by subclasses. This writes the \p Size bytes starting at
/// \p Ptr to the underlying stream.
///
/// This function is guaranteed to only be called at a point at which it is
/// safe for the subclass to install a new buffer via SetBuffer.
///
/// \param Ptr The start of the data to be written. For buffered streams this
/// is guaranteed to be the start of the buffer.
///
/// \param Size The number of bytes to be written.
///
/// \invariant { Size > 0 }
virtual void write_impl(const char *Ptr, size_t Size) = 0;
// An out of line virtual method to provide a home for the class vtable.
virtual void handle();
/// current_pos - Return the current position within the stream, not
/// counting the bytes currently in the buffer.
virtual uint64_t current_pos() const = 0;
protected:
/// SetBuffer - Use the provided buffer as the raw_ostream buffer. This is
/// intended for use only by subclasses which can arrange for the output to go
/// directly into the desired output buffer, instead of being copied on each
/// flush.
void SetBuffer(char *BufferStart, size_t Size) {
SetBufferAndMode(BufferStart, Size, ExternalBuffer);
}
/// preferred_buffer_size - Return an efficient buffer size for the
/// underlying output mechanism.
virtual size_t preferred_buffer_size() const;
/// getBufferStart - Return the beginning of the current stream buffer, or 0
/// if the stream is unbuffered.
const char *getBufferStart() const { return OutBufStart; }
//===--------------------------------------------------------------------===//
// Private Interface
//===--------------------------------------------------------------------===//
private:
/// SetBufferAndMode - Install the given buffer and mode.
void SetBufferAndMode(char *BufferStart, size_t Size, BufferKind Mode);
/// flush_nonempty - Flush the current buffer, which is known to be
/// non-empty. This outputs the currently buffered data and resets
/// the buffer to empty.
void flush_nonempty();
/// copy_to_buffer - Copy data into the buffer. Size must not be
/// greater than the number of unused bytes in the buffer.
void copy_to_buffer(const char *Ptr, size_t Size);
};
//===----------------------------------------------------------------------===//
// File Output Streams
//===----------------------------------------------------------------------===//
/// raw_fd_ostream - A raw_ostream that writes to a file descriptor.
///
class raw_fd_ostream : public raw_ostream {
int FD;
bool ShouldClose;
/// Error This flag is true if an error of any kind has been detected.
///
bool Error;
/// Controls whether the stream should attempt to use atomic writes, when
/// possible.
bool UseAtomicWrites;
uint64_t pos;
/// write_impl - See raw_ostream::write_impl.
void write_impl(const char *Ptr, size_t Size) override;
/// current_pos - Return the current position within the stream, not
/// counting the bytes currently in the buffer.
uint64_t current_pos() const override { return pos; }
/// preferred_buffer_size - Determine an efficient buffer size.
size_t preferred_buffer_size() const override;
/// error_detected - Set the flag indicating that an output error has
/// been encountered.
void error_detected() { Error = true; }
public:
/// raw_fd_ostream - Open the specified file for writing. If an error occurs,
/// information about the error is put into ErrorInfo, and the stream should
/// be immediately destroyed; the string will be empty if no error occurred.
/// This allows optional flags to control how the file will be opened.
///
/// As a special case, if Filename is "-", then the stream will use
/// STDOUT_FILENO instead of opening a file. Note that it will still consider
/// itself to own the file descriptor. In particular, it will close the
/// file descriptor when it is done (this is necessary to detect
/// output errors).
raw_fd_ostream(const char *Filename, std::string &ErrorInfo,
sys::fs::OpenFlags Flags);
/// raw_fd_ostream ctor - FD is the file descriptor that this writes to. If
/// ShouldClose is true, this closes the file when the stream is destroyed.
raw_fd_ostream(int fd, bool shouldClose, bool unbuffered=false);
~raw_fd_ostream();
/// close - Manually flush the stream and close the file.
/// Note that this does not call fsync.
void close();
/// seek - Flushes the stream and repositions the underlying file descriptor
/// position to the offset specified from the beginning of the file.
uint64_t seek(uint64_t off);
/// SetUseAtomicWrite - Set the stream to attempt to use atomic writes for
/// individual output routines where possible.
///
/// Note that because raw_ostream's are typically buffered, this flag is only
/// sensible when used on unbuffered streams which will flush their output
/// immediately.
void SetUseAtomicWrites(bool Value) {
UseAtomicWrites = Value;
}
raw_ostream &changeColor(enum Colors colors, bool bold=false,
bool bg=false) override;
raw_ostream &resetColor() override;
raw_ostream &reverseColor() override;
bool is_displayed() const override;
bool has_colors() const override;
/// has_error - Return the value of the flag in this raw_fd_ostream indicating
/// whether an output error has been encountered.
/// This doesn't implicitly flush any pending output. Also, it doesn't
/// guarantee to detect all errors unless the stream has been closed.
bool has_error() const {
return Error;
}
/// clear_error - Set the flag read by has_error() to false. If the error
/// flag is set at the time when this raw_ostream's destructor is called,
/// report_fatal_error is called to report the error. Use clear_error()
/// after handling the error to avoid this behavior.
///
/// "Errors should never pass silently.
/// Unless explicitly silenced."
/// - from The Zen of Python, by Tim Peters
///
void clear_error() {
Error = false;
}
};
/// outs() - This returns a reference to a raw_ostream for standard output.
/// Use it like: outs() << "foo" << "bar";
raw_ostream &outs();
/// errs() - This returns a reference to a raw_ostream for standard error.
/// Use it like: errs() << "foo" << "bar";
raw_ostream &errs();
/// nulls() - This returns a reference to a raw_ostream which simply discards
/// output.
raw_ostream &nulls();
//===----------------------------------------------------------------------===//
// Output Stream Adaptors
//===----------------------------------------------------------------------===//
/// raw_string_ostream - A raw_ostream that writes to an std::string. This is a
/// simple adaptor class. This class does not encounter output errors.
class raw_string_ostream : public raw_ostream {
std::string &OS;
/// write_impl - See raw_ostream::write_impl.
void write_impl(const char *Ptr, size_t Size) override;
/// current_pos - Return the current position within the stream, not
/// counting the bytes currently in the buffer.
uint64_t current_pos() const override { return OS.size(); }
public:
explicit raw_string_ostream(std::string &O) : OS(O) {}
~raw_string_ostream();
/// str - Flushes the stream contents to the target string and returns
/// the string's reference.
std::string& str() {
flush();
return OS;
}
};
/// raw_svector_ostream - A raw_ostream that writes to an SmallVector or
/// SmallString. This is a simple adaptor class. This class does not
/// encounter output errors.
class raw_svector_ostream : public raw_ostream {
SmallVectorImpl<char> &OS;
/// write_impl - See raw_ostream::write_impl.
void write_impl(const char *Ptr, size_t Size) override;
/// current_pos - Return the current position within the stream, not
/// counting the bytes currently in the buffer.
uint64_t current_pos() const override;
public:
/// Construct a new raw_svector_ostream.
///
/// \param O The vector to write to; this should generally have at least 128
/// bytes free to avoid any extraneous memory overhead.
explicit raw_svector_ostream(SmallVectorImpl<char> &O);
~raw_svector_ostream();
/// resync - This is called when the SmallVector we're appending to is changed
/// outside of the raw_svector_ostream's control. It is only safe to do this
/// if the raw_svector_ostream has previously been flushed.
void resync();
/// str - Flushes the stream contents to the target vector and return a
/// StringRef for the vector contents.
StringRef str();
};
/// raw_null_ostream - A raw_ostream that discards all output.
class raw_null_ostream : public raw_ostream {
/// write_impl - See raw_ostream::write_impl.
void write_impl(const char *Ptr, size_t size) override;
/// current_pos - Return the current position within the stream, not
/// counting the bytes currently in the buffer.
uint64_t current_pos() const override;
public:
explicit raw_null_ostream() {}
~raw_null_ostream();
};
} // end llvm namespace
#endif