llvm-mirror/lib/Support/circular_raw_ostream.cpp
David Greene f1f78a15e1 Add circular_raw_ostream, which buffers its output in a circular queue
and outputs it when explicitly flushed.  The intent is to use it in
situations such as debug output logging where a signal handler can take
care of flushing the buffer at program termination.

llvm-svn: 92001
2009-12-23 16:08:15 +00:00

48 lines
1.3 KiB
C++

//===- circulat_raw_ostream.cpp - Implement the circular_raw_ostream class -===//
//
// 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 circular buffered streams.
//
//===----------------------------------------------------------------------===//
#include "llvm/Support/circular_raw_ostream.h"
#include <algorithm>
using namespace llvm;
void circular_raw_ostream::write_impl(const char *Ptr, size_t Size) {
if (BufferSize == 0) {
TheStream->write(Ptr, Size);
return;
}
// Write into the buffer, wrapping if necessary.
while (Size != 0) {
unsigned Bytes = std::min(Size, BufferSize - (Cur - BufferArray));
memcpy(Cur, Ptr, Bytes);
Size -= Bytes;
Cur += Bytes;
if (Cur == BufferArray + BufferSize) {
// Reset the output pointer to the start of the buffer.
Cur = BufferArray;
Filled = true;
}
}
}
void circular_raw_ostream::flushBufferWithBanner(void) {
if (BufferSize != 0) {
// Write out the buffer
int num = std::strlen(Banner);
TheStream->write(Banner, num);
flushBuffer();
}
}