/**
* Read the list of ranges from the file.
* @param file the file to read
* @param base the base of the stripe
* @param ranges the disk ranges within the stripe to read
* @return the bytes read for each disk range, which is the same length as
* ranges
* @
*/
static DiskRangeList readDiskRanges(Stream file,
long @base,
DiskRangeList range,
bool doForceDirect)
{
if (range == null) return null;
DiskRangeList prev = range.prev;
if (prev == null)
{
prev = new DiskRangeList.MutateHelper(range);
}
while (range != null)
{
if (range.hasData())
{
range = range.next;
continue;
}
int len = (int)(range.getEnd() - range.getOffset());
long off = range.getOffset();
if (doForceDirect)
{
file.Seek(@base + off, SeekOrigin.Current);
ByteBuffer directBuf = ByteBuffer.allocateDirect(len);
readDirect(file, len, directBuf);
range = range.replaceSelfWith(new RecordReaderImpl.BufferChunk(directBuf, range.getOffset()));
}
else
{
byte[] buffer = new byte[len];
file.readFully((@base + off), buffer, 0, buffer.Length);
range = range.replaceSelfWith(new RecordReaderImpl.BufferChunk(ByteBuffer.wrap(buffer), range.getOffset()));
}
range = range.next;
}
return prev.next;
}
internal static List<DiskRange> getStreamBuffers(DiskRangeList range, long offset, long length)
{
// This assumes sorted ranges (as do many other parts of ORC code.
List<DiskRange> buffers = new List<DiskRange>();
if (length == 0) return buffers;
long streamEnd = offset + length;
bool inRange = false;
while (range != null)
{
if (!inRange)
{
if (range.getEnd() <= offset)
{
range = range.next;
continue; // Skip until we are in range.
}
inRange = true;
if (range.getOffset() < offset)
{
// Partial first buffer, add a slice of it.
buffers.Add(range.sliceAndShift(offset, Math.Min(streamEnd, range.getEnd()), -offset));
if (range.getEnd() >= streamEnd) break; // Partial first buffer is also partial last buffer.
range = range.next;
continue;
}
}
else if (range.getOffset() >= streamEnd)
{
break;
}
if (range.getEnd() > streamEnd)
{
// Partial last buffer (may also be the first buffer), add a slice of it.
buffers.Add(range.sliceAndShift(range.getOffset(), streamEnd, -offset));
break;
}
// Buffer that belongs entirely to one stream.
// TODO: ideally we would want to reuse the object and remove it from the list, but we cannot
// because bufferChunks is also used by clearStreams for zcr. Create a useless dup.
buffers.Add(range.sliceAndShift(range.getOffset(), range.getEnd(), -offset));
if (range.getEnd() == streamEnd) break;
range = range.next;
}
return buffers;
}