llvm-6502/include/llvm/Support/raw_ostream.h
Daniel Dunbar bcf8ea9554 raw_ostream: unbuffered streams weren't being immediately flushed on
single character writes.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@66827 91177308-0d34-0410-b5e6-96231b3b80d8
2009-03-12 22:02:44 +00:00

294 lines
8.9 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/StringExtras.h"
#include <cassert>
#include <cstring>
#include <string>
#include <iosfwd>
namespace llvm {
class format_object_base;
template <typename T>
class SmallVectorImpl;
/// 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 {
protected:
char *OutBufStart, *OutBufEnd, *OutBufCur;
bool Unbuffered;
public:
explicit raw_ostream(bool unbuffered=false) : Unbuffered(unbuffered) {
// Start out ready to flush.
OutBufStart = OutBufEnd = OutBufCur = 0;
}
virtual ~raw_ostream() {
delete [] OutBufStart;
}
//===--------------------------------------------------------------------===//
// Configuration Interface
//===--------------------------------------------------------------------===//
/// SetBufferSize - Set the internal buffer size to the specified amount
/// instead of the default.
void SetBufferSize(unsigned Size) {
assert(Size >= 64 &&
"Buffer size must be somewhat large for invariants to hold");
flush();
delete [] OutBufStart;
OutBufStart = new char[Size];
OutBufEnd = OutBufStart+Size;
OutBufCur = OutBufStart;
}
/// SetUnbuffered - Set the streams buffering status. 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(bool unbuffered) {
Unbuffered = unbuffered;
if (Unbuffered)
flush();
}
//===--------------------------------------------------------------------===//
// Data Output Interface
//===--------------------------------------------------------------------===//
void flush() {
if (OutBufCur != OutBufStart)
flush_impl();
}
raw_ostream &operator<<(char C) {
if (OutBufCur >= OutBufEnd)
flush_impl();
*OutBufCur++ = C;
if (Unbuffered)
flush_impl();
return *this;
}
raw_ostream &operator<<(unsigned char C) {
if (OutBufCur >= OutBufEnd)
flush_impl();
*OutBufCur++ = C;
if (Unbuffered)
flush_impl();
return *this;
}
raw_ostream &operator<<(signed char C) {
if (OutBufCur >= OutBufEnd)
flush_impl();
*OutBufCur++ = C;
if (Unbuffered)
flush_impl();
return *this;
}
raw_ostream &operator<<(const char *Str) {
return write(Str, strlen(Str));
}
raw_ostream &operator<<(const std::string& Str) {
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) {
return this->operator<<(ftostr(N));
}
raw_ostream &write(const char *Ptr, unsigned Size);
// Formatted output, see the format() function in Support/Format.h.
raw_ostream &operator<<(const format_object_base &Fmt);
//===--------------------------------------------------------------------===//
// Subclass Interface
//===--------------------------------------------------------------------===//
protected:
/// flush_impl - The is the piece of the class that is implemented by
/// subclasses. This outputs the currently buffered data and resets the
/// buffer to empty.
virtual void flush_impl() = 0;
/// HandleFlush - A stream's implementation of flush should call this after
/// emitting the bytes to the data sink.
void HandleFlush() {
if (OutBufStart == 0)
SetBufferSize(4096);
OutBufCur = OutBufStart;
}
private:
// An out of line virtual method to provide a home for the class vtable.
virtual void handle();
};
//===----------------------------------------------------------------------===//
// 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;
uint64_t pos;
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.
///
/// \param Filename - The file to open. If this is "-" then the
/// stream will use stdout instead.
/// \param Binary - The file should be opened in binary mode on
/// platforms that support this distinction.
raw_fd_ostream(const char *Filename, bool Binary, std::string &ErrorInfo);
/// 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_ostream(unbuffered), FD(fd),
ShouldClose(shouldClose) {}
~raw_fd_ostream();
/// flush_impl - The is the piece of the class that is implemented by
/// subclasses. This outputs the currently buffered data and resets the
/// buffer to empty.
virtual void flush_impl();
/// close - Manually flush the stream and close the file.
void close();
/// tell - Return the current offset with the file.
uint64_t tell() {
return pos + (OutBufCur - OutBufStart);
}
/// seek - Flushes the stream and repositions the underlying file descriptor
/// positition to the offset specified from the beginning of the file.
uint64_t seek(uint64_t off);
};
/// raw_stdout_ostream - This is a stream that always prints to stdout.
///
class raw_stdout_ostream : public raw_fd_ostream {
// An out of line virtual method to provide a home for the class vtable.
virtual void handle();
public:
raw_stdout_ostream();
};
/// raw_stderr_ostream - This is a stream that always prints to stderr.
///
class raw_stderr_ostream : public raw_fd_ostream {
// An out of line virtual method to provide a home for the class vtable.
virtual void handle();
public:
raw_stderr_ostream();
};
/// 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();
//===----------------------------------------------------------------------===//
// Output Stream Adaptors
//===----------------------------------------------------------------------===//
/// raw_os_ostream - A raw_ostream that writes to an std::ostream. This is a
/// simple adaptor class.
class raw_os_ostream : public raw_ostream {
std::ostream &OS;
public:
raw_os_ostream(std::ostream &O) : OS(O) {}
~raw_os_ostream();
/// flush_impl - The is the piece of the class that is implemented by
/// subclasses. This outputs the currently buffered data and resets the
/// buffer to empty.
virtual void flush_impl();
};
/// raw_string_ostream - A raw_ostream that writes to an std::string. This is a
/// simple adaptor class.
class raw_string_ostream : public raw_ostream {
std::string &OS;
public:
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;
}
/// flush_impl - The is the piece of the class that is implemented by
/// subclasses. This outputs the currently buffered data and resets the
/// buffer to empty.
virtual void flush_impl();
};
/// raw_svector_ostream - A raw_ostream that writes to an SmallVector or
/// SmallString. This is a simple adaptor class.
class raw_svector_ostream : public raw_ostream {
SmallVectorImpl<char> &OS;
public:
raw_svector_ostream(SmallVectorImpl<char> &O) : OS(O) {}
~raw_svector_ostream();
/// flush_impl - The is the piece of the class that is implemented by
/// subclasses. This outputs the currently buffered data and resets the
/// buffer to empty.
virtual void flush_impl();
};
} // end llvm namespace
#endif