94 lines
2.8 KiB
C++
94 lines
2.8 KiB
C++
/*
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* ZoneMinder flexible memory class implementation, $Date$, $Revision$
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* Copyright (C) 2001-2008 Philip Coombes
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program 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 program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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#include "zm_buffer.h"
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#include <unistd.h>
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unsigned int Buffer::assign(const unsigned char *pStorage, unsigned int pSize) {
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if ( mAllocation < pSize ) {
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delete[] mStorage;
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mAllocation = pSize;
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mHead = mStorage = new unsigned char[pSize];
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}
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mSize = pSize;
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memcpy(mStorage, pStorage, mSize);
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mHead = mStorage;
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mTail = mHead + mSize;
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return mSize;
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}
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unsigned int Buffer::expand(unsigned int count) {
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int spare = mAllocation - mSize;
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int headSpace = mHead - mStorage;
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int tailSpace = spare - headSpace;
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int width = mTail - mHead;
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if ( spare >= static_cast<int>(count) ) {
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// There is enough space in the allocation might need to shift everything over though
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//
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if ( tailSpace < static_cast<int>(count) ) {
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// if there is extra space at the head, shift everything over
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memmove(mStorage, mHead, mSize);
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mHead = mStorage;
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mTail = mHead + width;
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}
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} else {
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mAllocation += count;
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unsigned char *newStorage = new unsigned char[mAllocation];
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if ( mStorage ) {
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memcpy(newStorage, mHead, mSize);
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delete[] mStorage;
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}
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mStorage = newStorage;
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mHead = mStorage;
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mTail = mHead + width;
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}
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return mSize;
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}
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int Buffer::read_into(int sd, unsigned int bytes) {
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// Make sure there is enough space
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this->expand(bytes);
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Debug(3, "Reading %u bytes", bytes);
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int bytes_read = ::read(sd, mTail, bytes);
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if (bytes_read > 0) {
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mTail += bytes_read;
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mSize += bytes_read;
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}
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return bytes_read;
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}
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int Buffer::read_into(int sd, unsigned int bytes, Microseconds timeout) {
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fd_set set;
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FD_ZERO(&set); /* clear the set */
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FD_SET(sd, &set); /* add our file descriptor to the set */
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timeval timeout_tv = zm::chrono::duration_cast<timeval>(timeout);
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int rv = select(sd + 1, &set, nullptr, nullptr, &timeout_tv);
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if (rv == -1) {
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Error("Error %d %s from select", errno, strerror(errno));
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return rv;
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} else if (rv == 0) {
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Debug(1, "timeout"); /* a timeout occured */
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return 0;
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}
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return read_into(sd, bytes);
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}
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