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tdemultimedia/mpeglib/lib/frame/frameQueue.cpp

102 lines
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/*
queues frames
Copyright (C) 2001 Martin Vogt
This program 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.
For more information look at the file COPYRIGHT in this package
*/
#include "frameQueue.h"
#include <iostream>
using namespace std;
FrameQueue::FrameQueue(int maxsize) {
this->size=maxsize;
entries = new Frame*[size];
int i;
for(i=0;i<size;i++) {
entries[i]=NULL;
}
fillgrade=0;
writepos=0;
readpos=0;
}
FrameQueue::~FrameQueue() {
int i;
for(i=0;i<size;i++) {
if (entries[i] != NULL) {
delete entries[i];
}
}
delete entries;
}
int FrameQueue::canRead() {
return (fillgrade > 0);
}
int FrameQueue::canWrite() {
return (fillgrade < size);
}
int FrameQueue::getFillgrade() {
return fillgrade;
}
void FrameQueue::enqueue(Frame* frame) {
if(canWrite() == false) {
cout << "FrameQueue full cannot enqueue"<<endl;
exit(0);
}
fillgrade++;
entries[writepos]=frame;
writepos++;
if (writepos == size) {
writepos=0;
}
}
Frame* FrameQueue::dequeue() {
if(canRead() == false) {
cout << "FrameQueue empty cannot dequeue"<<endl;
exit(0);
}
Frame* back=entries[readpos];
// invalide this frame, we do not longer own it!
entries[readpos]=NULL;
fillgrade--;
readpos++;
if (readpos == size) {
readpos=0;
}
return back;
}
Frame* FrameQueue::peekqueue(int pos) {
if(fillgrade-pos <= 0) {
cout << "FrameQueue : cannot peek this positon"<<endl;
cout << "fillgrade:"<<fillgrade<<endl;
cout << "pos:"<<pos<<endl;
exit(0);
}
int getpos=(readpos+pos) % size;
Frame* back=entries[getpos];
return back;
}