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92c7695981
Most streams are backed by a memory buffer. Create common base classes for this functionality to avoid code duplication.
116 lines
2.9 KiB
C++
116 lines
2.9 KiB
C++
/* Copyright (C) 2002-2005 RealVNC Ltd. All Rights Reserved.
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* Copyright 2011-2020 Pierre Ossman for Cendio AB
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* Copyright 2017 Peter Astrand <astrand@cendio.se> for Cendio AB
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*
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* This is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This software is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this software; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
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* USA.
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*/
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#ifdef HAVE_CONFIG_H
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#include <config.h>
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#endif
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#include <rdr/BufferedOutStream.h>
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#include <rdr/Exception.h>
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using namespace rdr;
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static const size_t DEFAULT_BUF_SIZE = 16384;
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BufferedOutStream::BufferedOutStream(size_t bufSize_)
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: bufSize(bufSize_ ? bufSize_ : DEFAULT_BUF_SIZE), offset(0)
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{
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ptr = start = sentUpTo = new U8[bufSize];
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end = start + bufSize;
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}
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BufferedOutStream::~BufferedOutStream()
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{
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// FIXME: Complain about non-flushed buffer?
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delete [] start;
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}
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size_t BufferedOutStream::length()
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{
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return offset + ptr - sentUpTo;
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}
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size_t BufferedOutStream::bufferUsage()
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{
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return ptr - sentUpTo;
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}
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void BufferedOutStream::flush()
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{
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while (sentUpTo < ptr) {
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size_t len;
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len = bufferUsage();
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if (!flushBuffer(false))
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break;
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offset += len - bufferUsage();
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}
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// Managed to flush everything?
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if (sentUpTo == ptr)
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ptr = sentUpTo = start;
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}
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size_t BufferedOutStream::overrun(size_t itemSize, size_t nItems)
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{
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if (itemSize > bufSize)
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throw Exception("BufferedOutStream overrun: "
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"requested size of %lu bytes exceeds maximum of %lu bytes",
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(long unsigned)itemSize, (long unsigned)bufSize);
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// First try to get rid of the data we have
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flush();
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// Still not enough space?
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while (itemSize > avail()) {
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// Can we shuffle things around?
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// (don't do this if it gains us less than 25%)
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if (((size_t)(sentUpTo - start) > bufSize / 4) &&
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(itemSize < bufSize - (ptr - sentUpTo))) {
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memmove(start, sentUpTo, ptr - sentUpTo);
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ptr = start + (ptr - sentUpTo);
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sentUpTo = start;
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} else {
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size_t len;
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len = bufferUsage();
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// Have to get rid of more data, so allow the flush to wait...
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flushBuffer(true);
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offset += len - bufferUsage();
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// Managed to flush everything?
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if (sentUpTo == ptr)
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ptr = sentUpTo = start;
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}
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}
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size_t nAvail;
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nAvail = avail() / itemSize;
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if (nAvail < nItems)
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return nAvail;
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return nItems;
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}
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