Improve Range handling.

* allowing to GET last n bytes.
* start from GET range now spec conform (to field empty instead of Long.MAX_VALUE)

blobstore/src/main/java/org/jclouds/blobstore/functions/BlobToHttpGetOptions.java

@@ -51,11 +51,11 @@ public class BlobToHttpGetOptions implements Function<org.jclouds.blobstore.opti
          httpOptions.ifUnmodifiedSince(from.getIfUnmodifiedSince());
       }
       for (String range : from.getRanges()) {
-         String[] firstLast = range.split("\\-");
+         String[] firstLast = range.split("\\-", 2);
-         if (firstLast.length == 2)
+         if (!firstLast[0].isEmpty() && !firstLast[1].isEmpty())
             httpOptions.range(Long.parseLong(firstLast[0]), Long.parseLong(firstLast[1]));
-         else if (range.startsWith("-"))
+         else if (firstLast[0].isEmpty() && !firstLast[1].isEmpty())
-            httpOptions.tail(Long.parseLong(firstLast[0]));
+            httpOptions.tail(Long.parseLong(firstLast[1]));
          else
             httpOptions.startAt(Long.parseLong(firstLast[0]));
       }

blobstore/src/main/java/org/jclouds/blobstore/options/GetOptions.java

@@ -72,6 +72,16 @@ public class GetOptions {
       return this;
    }
 
+
+   /**
+    * download the specified range of the object starting from the end of the object.
+    */
+   public GetOptions tail(long length) {
+      checkArgument(length >= 0, "length must be >= 0");
+      getRanges().add(String.format("-%d", length));
+      return this;
+   }
+
    /**
     * Only return the object if it has changed since this time.
     * <p />

blobstore/src/test/java/org/jclouds/blobstore/functions/BlobToHttpGetOptionsTest.java

@@ -104,6 +104,29 @@ public class BlobToHttpGetOptionsTest {
 
    }
 
+   @Test
+   public void testRangesTail(){
+      org.jclouds.blobstore.options.GetOptions in = new org.jclouds.blobstore.options.GetOptions();
+      in.tail(1024);
+
+      GetOptions expected = new GetOptions();
+      expected.tail(1024);
+
+      assertEquals(fn.apply(in), expected);
+
+   }
+   @Test
+   public void testRangesStart(){
+      org.jclouds.blobstore.options.GetOptions in = new org.jclouds.blobstore.options.GetOptions();
+      in.startAt(1024);
+
+      GetOptions expected = new GetOptions();
+      expected.startAt(1024);
+
+      assertEquals(fn.apply(in), expected);
+
+   }
+   
    @Test(expectedExceptions = { NullPointerException.class, IllegalStateException.class })
    public void testNullIsBad() {
       fn.apply(null);

blobstore/src/test/java/org/jclouds/blobstore/options/GetOptionsTest.java

@@ -136,6 +136,21 @@ public class GetOptionsTest {
       assertEquals(options.getRanges(), ImmutableList.of("0-5", "10-100"));
    }
 
+
+   @Test
+   public void testRangeStartAt() {
+      GetOptions options = new GetOptions();
+      options.startAt(5);
+      assertEquals(options.getRanges(), ImmutableList.of("5-"));
+   }
+
+   @Test
+   public void testRangeTail() {
+      GetOptions options = new GetOptions();
+      options.tail(5);
+      assertEquals(options.getRanges(), ImmutableList.of("-5"));
+   }
+
    @Test
    public void testNoRange() {
       GetOptions options = new GetOptions();

core/src/main/java/org/jclouds/http/options/GetOptions.java

@@ -80,7 +80,7 @@ public class GetOptions extends BaseHttpRequestOptions {
     */
    public GetOptions startAt(long start) {
       checkArgument(start >= 0, "start must be >= 0");
-      ranges.add(String.format("%d-%d", start, Long.MAX_VALUE));
+      ranges.add(String.format("%d-", start));
       return this;
    }
 

core/src/test/java/org/jclouds/http/options/GetOptionsTest.java

@@ -155,13 +155,13 @@ public class GetOptionsTest {
    public void testStartAt() {
       GetOptions options = new GetOptions();
       options.startAt(100);
-      assertEquals(options.getRange(), "bytes=100-9223372036854775807");
+      assertEquals(options.getRange(), "bytes=100-");
    }
 
    @Test
    public void testStartAtStatic() {
       GetOptions options = startAt(100);
-      assertEquals(options.getRange(), "bytes=100-9223372036854775807");
+      assertEquals(options.getRange(), "bytes=100-");
    }
 
    @Test(expectedExceptions = IllegalArgumentException.class)