diff --git a/core/src/main/groovy/com/muwire/core/FileHasher.groovy b/core/src/main/groovy/com/muwire/core/FileHasher.groovy
index 18ce2503..cd952cd3 100644
--- a/core/src/main/groovy/com/muwire/core/FileHasher.groovy
+++ b/core/src/main/groovy/com/muwire/core/FileHasher.groovy
@@ -3,7 +3,7 @@ package com.muwire.core
 class FileHasher {
 
 	/** max size of shared file is 128 GB */
-	public static final long MAX_SIZE = 0x1 << 37
+	public static final long MAX_SIZE = 0x1L << 37
 	
 	/**
 	 * @param size of the file to be shared
@@ -14,7 +14,7 @@ class FileHasher {
 			return 18
 		
 		for (int i = 26; i <= 37; i++) {
-			if (size <= 0x1 << i) {
+			if (size <= 0x1L << i) {
 				return i-7
 			}
 		}
diff --git a/core/src/test/groovy/com/muwire/core/FileHasherTest.groovy b/core/src/test/groovy/com/muwire/core/FileHasherTest.groovy
index 61cc2409..3c3512b9 100644
--- a/core/src/test/groovy/com/muwire/core/FileHasherTest.groovy
+++ b/core/src/test/groovy/com/muwire/core/FileHasherTest.groovy
@@ -10,6 +10,7 @@ class FileHasherTest extends GroovyTestCase {
 	void testPieceSize() {
 		assert 18 == FileHasher.getPieceSize(1000000)
 		assert 20 == FileHasher.getPieceSize(100000000)
+		assert 30 == FileHasher.getPieceSize(FileHasher.MAX_SIZE)
 		shouldFail IllegalArgumentException, {
 			FileHasher.getPieceSize(Long.MAX_VALUE)
 		}