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arts/flow/pipebuffer.cpp

167 lines
3.1 KiB

/*
Copyright (C) 2000 Stefan Westerfeld
stefan@space.twc.de
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public
License as published by the Free Software Foundation; either
version 2 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Library General Public License for more details.
You should have received a copy of the GNU Library General Public License
along with this library; see the file COPYING.LIB. If not, write to
the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
Boston, MA 02110-1301, USA.
*/
#include "pipebuffer.h"
#include <assert.h>
#include <cstring>
using namespace std;
using namespace Arts;
PipeSegment::PipeSegment(long size, void *buffer)
{
this->buffer = new char[size];
this->currentpos = this->buffer;
memcpy(this->buffer,buffer,size);
_remaining = size;
}
PipeSegment::~PipeSegment()
{
delete[] buffer;
}
void *PipeSegment::data()
{
return currentpos;
}
long PipeSegment::remaining()
{
return _remaining;
}
void PipeSegment::skip(long count)
{
_remaining -= count;
currentpos += count;
assert(_remaining >= 0);
}
PipeBuffer::PipeBuffer()
{
_size = 0;
}
PipeBuffer::~PipeBuffer()
{
clear();
}
void PipeBuffer::clear()
{
while(segments.size() != 0)
{
PipeSegment *first = *segments.begin();
delete first;
segments.pop_front();
}
_size = 0;
}
void *PipeBuffer::peek(long size)
{
while(!segments.empty())
{
PipeSegment *first = *segments.begin();
if(size <= first->remaining())
return first->data();
}
return 0;
}
void PipeBuffer::skip(long size)
{
while(!segments.empty() && size > 0)
{
PipeSegment *first = *segments.begin();
// if we have less data to skip than the first segment contains
if(size < first->remaining())
{
// skip the data inside the segment
_size -= size;
first->skip(size);
return;
}
else
{
// otherwise erase the first segment
_size -= first->remaining();
size -= first->remaining();
delete first;
segments.pop_front();
}
}
}
long PipeBuffer::read(long size, void *buffer)
{
long readbytes = 0;
char *bptr = (char *)buffer;
while(!segments.empty() && size > 0)
{
PipeSegment *first = *segments.begin();
long readCnt = size;
if(readCnt > first->remaining()) readCnt = first->remaining();
memcpy(bptr,first->data(),readCnt);
first->skip(readCnt);
size -= readCnt;
bptr += readCnt;
readbytes += readCnt;
if(first->remaining() == 0)
{
delete first;
segments.pop_front();
}
}
_size -= readbytes;
return readbytes;
}
long PipeBuffer::size()
{
return _size;
}
void PipeBuffer::write(long size, void *buffer)
{
segments.push_back(new PipeSegment(size,buffer));
_size += size;
}
void PipeBuffer::unRead(long size, void *buffer)
{
segments.push_front(new PipeSegment(size,buffer));
_size += size;
}