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=44ceccfab52a13a5ced20108ad539cafbf2c6fb2;hb=842bb718cc05d82d37cf6464175baa9f05c80297;hp=0791cd833c28fc7a2acd14cb4901a1a675d3cae2;hpb=5db8794926ba12d45ed0f652a9c9e6e9db1cde3d;p=GpsPrune.git

diff --git a/src/tim/prune/function/srtm/SrtmSource.java b/src/tim/prune/function/srtm/SrtmSource.java
index 0791cd8..44ceccf 100644
--- a/src/tim/prune/function/srtm/SrtmSource.java
+++ b/src/tim/prune/function/srtm/SrtmSource.java
@@ -19,11 +19,19 @@ public abstract class SrtmSource {
 		throws IOException
 	{
 		int[] heights = new int[tileSize];
+		int dataSize = 2 * tileSize;
+		byte[] buffer = new byte[dataSize];
 		// Read entire file contents into one byte array
-		for (int i = 0; i < heights.length; i++)
+		int alreadyRead = 0;
+		while (alreadyRead < dataSize)
 		{
-			heights[i] = inStream.read() * 256 + inStream.read();
-			if (heights[i] >= 32768) {heights[i] -= 65536;}
+			alreadyRead += inStream.read(buffer, alreadyRead, dataSize - alreadyRead);
+		}
+		for (int i = 0; i < tileSize; i++)
+		{
+			// Bytes are signed. Cast high-order to int with sign
+			// extension, and clamp low-order to its unsigned range
+			heights[i] = buffer[2 * i] * 256 + (0xff & buffer[2 * i + 1]);
 		}
 		// Close stream
 		inStream.close();