/**
* @param start Start time
* @return Index sample with time stamp at-or-before start time, or -1.
*/
private int findSampleLessOrEqual(final Instant start) {
// Would like to use PlotSampleSearch, but that operates on array
// of PlotSample[]
int low = 0;
int high = samples.size() - 1;
int cmp = 0;
int mid = -1;
while (low <= high) {
mid = (low + high) / 2;
// Compare 'mid' sample to goal
final Instant time = samples.get(mid).getPosition();
final int compare = time.compareTo(start);
if (compare > 0) { // 'mid' too big, search lower half
cmp = 1;
high = mid - 1;
} else if (compare < 0) { // 'mid' too small, search upper half
cmp = -1;
low = mid + 1;
} else {
cmp = 0;
return mid; // found exact time
}
}
// Didn't find exact match.
if (cmp < 0) // 'mid' sample is smaller than x, so it's OK
return mid;
// cmp > 0, 'mid' sample is greater than x.
// If there is a sample before, use that
if (mid > 0) return mid - 1;
return -1;
}
/** {@inheritDoc} */
@Override
public VType next() throws Exception {
if (index < 0) throw new Exception("End of samples"); // $NON-NLS-1$
// Remember value, prepare the next value
final VType result = value;
samples.getLock().lock();
try {
++index;
if (index >= samples.size()) index = -1; // No more samples
else {
value = samples.get(index).getVType();
if (VTypeHelper.getTimestamp(value).compareTo(end) > 0) index = -1; // Beyond end time
}
} finally {
samples.getLock().unlock();
}
return result;
}
/**
* Initialize
*
* @param item Item from which to get samples /** @param start Start time /** @param end End time
*/
public ModelSampleIterator(final ModelItem item, final Instant start, final Instant end) {
this.samples = item.getSamples();
this.end = end;
samples.getLock().lock();
try {
// Anything?
if (samples.size() <= 0) index = -1;
// All data after start time?
else if (samples.get(0).getPosition().compareTo(start) >= 0) index = 0;
else { // There is data before the start time. Find sample just before start time.
index = findSampleLessOrEqual(start);
}
// Is first sample already after end time?
if (index >= 0) {
final PlotSample sample = samples.get(index);
value = sample.getVType();
if (sample.getPosition().compareTo(end) > 0) index = -1;
}
} finally {
samples.getLock().unlock();
}
}
