Added StreamingSegmentBytes

Signed-off-by: jbouffard <jbouffard@azavea.com>

raster/src/main/scala/geotrellis/raster/io/geotiff/StreamingSegmentBytes.scala

@@ -0,0 +1,109 @@
+package geotrellis.raster.io.geotiff
+
+import geotrellis.util._
+import geotrellis.raster._
+import geotrellis.raster.io.geotiff.tags._
+import geotrellis.raster.io.geotiff.util._
+import geotrellis.vector.Extent
+
+import spire.syntax.cfor._
+import monocle.syntax.apply._
+
+class StreamingSegmentBytes(byteReader: ByteReader,
+	segmentLayout: GeoTiffSegmentLayout,
+	croppedExtent: Option[Extent],
+	tiffTags: TiffTags) extends SegmentBytes {
+
+	private val extent: Extent =
+		croppedExtent match {
+			case Some(e) => e
+			case None => tiffTags.extent
+		}
+
+	private val gridBounds: GridBounds = {
+		val rasterExtent: RasterExtent =
+			RasterExtent(tiffTags.extent, tiffTags.cols, tiffTags.rows)
+		rasterExtent.gridBoundsFor(extent)
+	}
+
+	private val colMin: Int = gridBounds.colMin
+	private val rowMin: Int = gridBounds.rowMin
+	private val colMax: Int = gridBounds.colMax
+	private val rowMax: Int = gridBounds.rowMax
+
+	val segments: Array[Int] = (0 until tiffTags.segmentCount).toArray
+
+	val intersectingSegments: Array[Int] =
+		if (extent != tiffTags.extent)
+			segments.filter(x => {
+				val segmentTransform = segmentLayout.getSegmentTransform(x)
+
+				val startCol: Int = segmentTransform.indexToCol(0)
+				val startRow: Int = segmentTransform.indexToRow(0)
+				val endCol: Int = startCol + segmentTransform.segmentCols
+				val endRow: Int = startRow + segmentTransform.segmentRows
+
+				val start = (!(startCol > colMax) && !(startRow > rowMax))
+				val end = (!(endCol < colMin) && !(endRow < rowMin))
+
+				if (start && end)
+					println(endCol, endRow, colMax, rowMax)
+
+				(start && end)
+
+			}).toArray.sorted
+		else
+			segments
+
+	val remainingSegments: Array[Int] =
+		segments.filter(x => !intersectingSegments.contains(x))
+
+	val (offsets, byteCounts) =
+		if (tiffTags.hasStripStorage) {
+			val stripOffsets = (tiffTags &|->
+				TiffTags._basicTags ^|->
+				BasicTags._stripOffsets get)
+
+			val stripByteCounts = (tiffTags &|->
+				TiffTags._basicTags ^|->
+				BasicTags._stripByteCounts get)
+
+			(stripOffsets.get, stripByteCounts.get)
+
+		} else {
+			val tileOffsets = (tiffTags &|->
+				TiffTags._tileTags ^|->
+				TileTags._tileOffsets get)
+
+			val tileByteCounts = (tiffTags &|->
+				TiffTags._tileTags ^|->
+				TileTags._tileByteCounts get)
+
+			(tileOffsets.get, tileByteCounts.get)
+		}
+
+	private lazy val compressedBytes: Array[Array[Byte]] = {
+		val result = Array.ofDim[Array[Byte]](segments.size)
+
+		cfor(0)(_ < intersectingSegments.size, _ + 1) { i =>
+			val value = intersectingSegments(i)
+			result(value) = byteReader.getSignedByteArray(byteCounts(value), offsets(value))
+		}
+		result
+	}
+
+	override val size = offsets.size
+
+	def getSegment(i: Int): Array[Byte] =
+		if (intersectingSegments.contains(i))
+			compressedBytes(i)
+		else
+			byteReader.getSignedByteArray(byteCounts(i), offsets(i))
+	}
+
+object StreamingSegmentBytes {
+
+	def apply(byteReader: ByteReader, segmentLayout: GeoTiffSegmentLayout,
+		extent: Option[Extent], tiffTags: TiffTags): StreamingSegmentBytes =
+			new StreamingSegmentBytes(byteReader, segmentLayout, extent, tiffTags)
+}