public void CanRoundTrip()
{
var bufferLength = 20;
var input = new long[] { 1234, 5678, 9101112, 13141516, 17181920, 21222324 };
var buffer = ByteBuffer.Allocate(bufferLength);
foreach (var value in input)
{
ZigZagEncoding.PutLong(buffer, value);
}
buffer.Position = 0;
var output = new long[input.Length];
for (int i = 0; i < output.Length; i++)
{
output[i] = ZigZagEncoding.GetLong(buffer);
}
CollectionAssert.AreEqual(input, output);
}
private static int FillBufferFromCountsArray(ByteBuffer buffer, IRecordedData data)
{
int startPosition = buffer.Position;
int srcIndex = 0;
while (srcIndex < data.Counts.Length)
{
// V2 encoding format uses a ZigZag LEB128-64b9B encoded long.
// Positive values are counts, while negative values indicate a repeat zero counts. i.e. -4 indicates 4 sequential buckets with 0 counts.
long count = GetCountAtIndex(srcIndex++, data);
if (count < 0)
{
throw new InvalidOperationException($"Cannot encode histogram containing negative counts ({count}) at index {srcIndex}");
}
// Count trailing 0s (which follow this count):
long zerosCount = 0;
if (count == 0)
{
zerosCount = 1;
while ((srcIndex < data.Counts.Length) && (GetCountAtIndex(srcIndex, data) == 0))
{
zerosCount++;
srcIndex++;
}
}
if (zerosCount > 1)
{
ZigZagEncoding.PutLong(buffer, -zerosCount);
}
else
{
ZigZagEncoding.PutLong(buffer, count);
}
}
return(buffer.Position - startPosition);
}
public int ReadCounts(ByteBuffer sourceBuffer, int lengthInBytes, int maxIndex, Action <int, long> setCount)
{
var idx = 0;
int endPosition = sourceBuffer.Position + lengthInBytes;
while (sourceBuffer.Position < endPosition && idx < maxIndex)
{
var item = ZigZagEncoding.GetLong(sourceBuffer);
if (item < 0)
{
var zeroCounts = -(item);
if (zeroCounts > int.MaxValue)
{
throw new ArgumentException("An encoded zero count of > int.MaxValue was encountered in the source");
}
idx += (int)zeroCounts;
}
else
{
setCount(idx++, item);
}
}
return(idx);
}
