X-Git-Url: http://gitweb.fperrin.net/?a=blobdiff_plain;f=src%2Ftim%2Fprune%2Ffunction%2Fsrtm%2FSrtmSource.java;fp=src%2Ftim%2Fprune%2Ffunction%2Fsrtm%2FSrtmSource.java;h=5651a3f314656b155e979056ba1deafd0a6cb671;hb=189a667821db055202dcb9f539ee26bd2af7ade4;hp=0000000000000000000000000000000000000000;hpb=2302358503c38817e19f6e529f6c9e530aac0e86;p=GpsPrune.git

diff --git a/src/tim/prune/function/srtm/SrtmSource.java b/src/tim/prune/function/srtm/SrtmSource.java
new file mode 100644
index 0000000..5651a3f
--- /dev/null
+++ b/src/tim/prune/function/srtm/SrtmSource.java
@@ -0,0 +1,69 @@
+package tim.prune.function.srtm;
+
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.util.zip.ZipEntry;
+import java.util.zip.ZipInputStream;
+
+public abstract class SrtmSource {
+	public abstract String getName();
+	public abstract boolean isReadyToUse();
+	public abstract boolean downloadTile(SrtmTile inTile)
+		throws SrtmSourceException;
+	public abstract int getRowSize(SrtmTile inTile);
+	protected abstract String getSourceExtension();
+
+	public int[] getTileHeights(SrtmTile inTile)
+		throws SrtmSourceException
+	{
+		File cacheFileName = getCacheFileName(inTile);
+		if (cacheFileName == null)
+		{
+			throw new SrtmSourceException("Tile "+inTile.getTileName()+" not in cache");
+		}
+		try
+		{
+			ZipInputStream inStream = new ZipInputStream(new FileInputStream(cacheFileName));
+			ZipEntry entry = inStream.getNextEntry();
+			int rowSize = getRowSize(inTile);
+			int tileSize = rowSize * rowSize;
+			if (entry.getSize() != 2 * tileSize)
+			{
+				throw new SrtmSourceException("Tile file "+cacheFileName+" does not have the expected size");
+			}
+			int[] heights = new int[tileSize];
+			// Read entire file contents into one byte array
+			for (int i = 0; i < heights.length; i++)
+			{
+				heights[i] = inStream.read() * 256 + inStream.read();
+				if (heights[i] >= 32768) {heights[i] -= 65536;}
+			}
+			// Close stream
+			inStream.close();
+			return heights;
+		}
+		catch (IOException e)
+		{
+			throw new SrtmSourceException("Failure opening "+cacheFileName+" for reading:"+e.getMessage());
+		}
+
+	}
+
+	protected File getCacheDir()
+	{
+		return SrtmDiskCache.getCacheDir(getName());
+	}
+
+	protected File getCacheFileName(SrtmTile inTile)
+	{
+		String fileName = inTile.getTileName() + getSourceExtension();
+		return new File(getCacheDir(), fileName);
+	}
+
+	public boolean isCached(SrtmTile inTile)
+	{
+		return getCacheFileName(inTile).exists();
+	}
+}