llvm-6502/lib/Support/raw_ostream.cpp
Daniel Dunbar d17d74bb80 raw_ostream: Rework implementation of unbuffered streams so outputting
a single character requires only one branch to follow slow path.
 - Never use a buffer when writing on an unbuffered stream.

 - Move default buffer size to header.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@67066 91177308-0d34-0410-b5e6-96231b3b80d8
2009-03-17 01:13:35 +00:00

353 lines
9.0 KiB
C++

//===--- raw_ostream.cpp - Implement the raw_ostream classes --------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This implements support for bulk buffered stream output.
//
//===----------------------------------------------------------------------===//
#include "llvm/Support/raw_ostream.h"
#include "llvm/Support/Format.h"
#include "llvm/System/Program.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/Config/config.h"
#include <ostream>
#if defined(HAVE_UNISTD_H)
# include <unistd.h>
#endif
#if defined(HAVE_FCNTL_H)
# include <fcntl.h>
#endif
#if defined(_MSC_VER)
#include <io.h>
#include <fcntl.h>
#ifndef STDIN_FILENO
# define STDIN_FILENO 0
#endif
#ifndef STDOUT_FILENO
# define STDOUT_FILENO 1
#endif
#ifndef STDERR_FILENO
# define STDERR_FILENO 2
#endif
#endif
using namespace llvm;
// An out of line virtual method to provide a home for the class vtable.
void raw_ostream::handle() {}
raw_ostream &raw_ostream::operator<<(unsigned long N) {
// Zero is a special case.
if (N == 0)
return *this << '0';
char NumberBuffer[20];
char *EndPtr = NumberBuffer+sizeof(NumberBuffer);
char *CurPtr = EndPtr;
while (N) {
*--CurPtr = '0' + char(N % 10);
N /= 10;
}
return write(CurPtr, EndPtr-CurPtr);
}
raw_ostream &raw_ostream::operator<<(long N) {
if (N < 0) {
*this << '-';
N = -N;
}
return this->operator<<(static_cast<unsigned long>(N));
}
raw_ostream &raw_ostream::operator<<(unsigned long long N) {
// Zero is a special case.
if (N == 0)
return *this << '0';
char NumberBuffer[20];
char *EndPtr = NumberBuffer+sizeof(NumberBuffer);
char *CurPtr = EndPtr;
while (N) {
*--CurPtr = '0' + char(N % 10);
N /= 10;
}
return write(CurPtr, EndPtr-CurPtr);
}
raw_ostream &raw_ostream::operator<<(long long N) {
if (N < 0) {
*this << '-';
N = -N;
}
return this->operator<<(static_cast<unsigned long long>(N));
}
raw_ostream &raw_ostream::operator<<(const void *P) {
uintptr_t N = (uintptr_t) P;
*this << '0' << 'x';
// Zero is a special case.
if (N == 0)
return *this << '0';
char NumberBuffer[20];
char *EndPtr = NumberBuffer+sizeof(NumberBuffer);
char *CurPtr = EndPtr;
while (N) {
unsigned x = N % 16;
*--CurPtr = (x < 10 ? '0' + x : 'a' + x - 10);
N /= 16;
}
return write(CurPtr, EndPtr-CurPtr);
}
void raw_ostream::flush_nonempty() {
assert(OutBufCur > OutBufStart && "Invalid call to flush_nonempty.");
write_impl(OutBufStart, OutBufCur - OutBufStart);
OutBufCur = OutBufStart;
}
raw_ostream &raw_ostream::write(unsigned char C) {
if (Unbuffered) {
write_impl(reinterpret_cast<char*>(&C), 1);
return *this;
}
if (!OutBufStart)
SetBufferSize();
else if (OutBufCur >= OutBufEnd)
flush_nonempty();
*OutBufCur++ = C;
return *this;
}
raw_ostream &raw_ostream::write(const char *Ptr, unsigned Size) {
if (Unbuffered) {
write_impl(Ptr, Size);
return *this;
}
if (!OutBufStart)
SetBufferSize();
else if (OutBufCur+Size > OutBufEnd)
flush_nonempty();
// Handle short strings specially, memcpy isn't very good at very short
// strings.
switch (Size) {
case 4: OutBufCur[3] = Ptr[3]; // FALL THROUGH
case 3: OutBufCur[2] = Ptr[2]; // FALL THROUGH
case 2: OutBufCur[1] = Ptr[1]; // FALL THROUGH
case 1: OutBufCur[0] = Ptr[0]; // FALL THROUGH
case 0: break;
default:
// Normally the string to emit is shorter than the buffer.
if (Size <= unsigned(OutBufEnd-OutBufStart)) {
memcpy(OutBufCur, Ptr, Size);
break;
}
// Otherwise we are emitting a string larger than our buffer. We
// know we already flushed, so just write it out directly.
write_impl(Ptr, Size);
Size = 0;
break;
}
OutBufCur += Size;
return *this;
}
// Formatted output.
raw_ostream &raw_ostream::operator<<(const format_object_base &Fmt) {
// If we have more than a few bytes left in our output buffer, try formatting
// directly onto its end.
unsigned NextBufferSize = 127;
if (OutBufEnd-OutBufCur > 3) {
unsigned BufferBytesLeft = OutBufEnd-OutBufCur;
unsigned BytesUsed = Fmt.print(OutBufCur, BufferBytesLeft);
// Common case is that we have plenty of space.
if (BytesUsed < BufferBytesLeft) {
OutBufCur += BytesUsed;
return *this;
}
// Otherwise, we overflowed and the return value tells us the size to try
// again with.
NextBufferSize = BytesUsed;
}
// If we got here, we didn't have enough space in the output buffer for the
// string. Try printing into a SmallVector that is resized to have enough
// space. Iterate until we win.
SmallVector<char, 128> V;
while (1) {
V.resize(NextBufferSize);
// Try formatting into the SmallVector.
unsigned BytesUsed = Fmt.print(&V[0], NextBufferSize);
// If BytesUsed fit into the vector, we win.
if (BytesUsed <= NextBufferSize)
return write(&V[0], BytesUsed);
// Otherwise, try again with a new size.
assert(BytesUsed > NextBufferSize && "Didn't grow buffer!?");
NextBufferSize = BytesUsed;
}
}
//===----------------------------------------------------------------------===//
// Formatted Output
//===----------------------------------------------------------------------===//
// Out of line virtual method.
void format_object_base::home() {
}
//===----------------------------------------------------------------------===//
// raw_fd_ostream
//===----------------------------------------------------------------------===//
/// 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.
raw_fd_ostream::raw_fd_ostream(const char *Filename, bool Binary,
std::string &ErrorInfo) : pos(0) {
ErrorInfo.clear();
// Handle "-" as stdout.
if (Filename[0] == '-' && Filename[1] == 0) {
FD = STDOUT_FILENO;
// If user requested binary then put stdout into binary mode if
// possible.
if (Binary)
sys::Program::ChangeStdoutToBinary();
ShouldClose = false;
return;
}
int Flags = O_WRONLY|O_CREAT|O_TRUNC;
#ifdef O_BINARY
if (Binary)
Flags |= O_BINARY;
#endif
FD = open(Filename, Flags, 0644);
if (FD < 0) {
ErrorInfo = "Error opening output file '" + std::string(Filename) + "'";
ShouldClose = false;
} else {
ShouldClose = true;
}
}
raw_fd_ostream::~raw_fd_ostream() {
if (FD >= 0) {
flush();
if (ShouldClose)
::close(FD);
}
}
void raw_fd_ostream::write_impl(const char *Ptr, unsigned Size) {
assert (FD >= 0 && "File already closed.");
pos += Size;
::write(FD, Ptr, Size);
}
void raw_fd_ostream::close() {
assert (ShouldClose);
ShouldClose = false;
flush();
::close(FD);
FD = -1;
}
uint64_t raw_fd_ostream::seek(uint64_t off) {
flush();
pos = lseek(FD, off, SEEK_SET);
return pos;
}
//===----------------------------------------------------------------------===//
// raw_stdout/err_ostream
//===----------------------------------------------------------------------===//
raw_stdout_ostream::raw_stdout_ostream():raw_fd_ostream(STDOUT_FILENO, false) {}
raw_stderr_ostream::raw_stderr_ostream():raw_fd_ostream(STDERR_FILENO, false,
true) {}
// An out of line virtual method to provide a home for the class vtable.
void raw_stdout_ostream::handle() {}
void raw_stderr_ostream::handle() {}
/// outs() - This returns a reference to a raw_ostream for standard output.
/// Use it like: outs() << "foo" << "bar";
raw_ostream &llvm::outs() {
static raw_stdout_ostream S;
return S;
}
/// errs() - This returns a reference to a raw_ostream for standard error.
/// Use it like: errs() << "foo" << "bar";
raw_ostream &llvm::errs() {
static raw_stderr_ostream S;
return S;
}
//===----------------------------------------------------------------------===//
// raw_os_ostream
//===----------------------------------------------------------------------===//
raw_os_ostream::~raw_os_ostream() {
flush();
}
void raw_os_ostream::write_impl(const char *Ptr, unsigned Size) {
OS.write(Ptr, Size);
}
//===----------------------------------------------------------------------===//
// raw_string_ostream
//===----------------------------------------------------------------------===//
raw_string_ostream::~raw_string_ostream() {
flush();
}
void raw_string_ostream::write_impl(const char *Ptr, unsigned Size) {
OS.append(Ptr, Size);
}
//===----------------------------------------------------------------------===//
// raw_svector_ostream
//===----------------------------------------------------------------------===//
raw_svector_ostream::~raw_svector_ostream() {
flush();
}
void raw_svector_ostream::write_impl(const char *Ptr, unsigned Size) {
OS.append(Ptr, Ptr + Size);
}