Fix casting in GridFSDownloadImpl

JAVA-2548

Author: rozza

driver/src/main/com/mongodb/client/gridfs/GridFSDownloadStreamImpl.java

@@ -114,7 +114,7 @@ public long skip(final long bytesToSkip) {
         }
 
         long skippedPosition = currentPosition + bytesToSkip;
-        bufferOffset = (int) skippedPosition % chunkSizeInBytes;
+        bufferOffset = (int) (skippedPosition % chunkSizeInBytes);
         if (skippedPosition >= length) {
             long skipped = length - currentPosition;
             chunkIndex = numberOfChunks - 1;
@@ -123,7 +123,7 @@ public long skip(final long bytesToSkip) {
             discardCursor();
             return skipped;
         } else {
-            int newChunkIndex = (int) Math.floor((float) skippedPosition / chunkSizeInBytes);
+            int newChunkIndex = (int) Math.floor(skippedPosition / (double) chunkSizeInBytes);
             if (chunkIndex != newChunkIndex) {
                 chunkIndex = newChunkIndex;
                 buffer = null;
@@ -161,9 +161,9 @@ public synchronized void reset() {
             return;
         }
 
-        bufferOffset = (int) markPosition % chunkSizeInBytes;
+        bufferOffset = (int) (markPosition % chunkSizeInBytes);
         currentPosition = markPosition;
-        int markChunkIndex = (int) Math.floor((float) markPosition / chunkSizeInBytes);
+        int markChunkIndex = (int) Math.floor(markPosition / (double) chunkSizeInBytes);
         if (markChunkIndex != chunkIndex) {
             chunkIndex = markChunkIndex;
             buffer = null;

driver/src/test/unit/com/mongodb/client/gridfs/GridFSDownloadStreamSpecification.groovy

@@ -169,18 +169,19 @@ class GridFSDownloadStreamSpecification extends Specification {
 
     def 'should skip to the correct point'() {
         given:
-        def fileInfo = new GridFSFile(new BsonObjectId(new ObjectId()), 'filename', 60L, 25, new Date(), 'abc', new Document())
+        def fileInfo = new GridFSFile(new BsonObjectId(new ObjectId()), 'filename', 4194297L, 32,
+                new Date(), 'abc', new Document())
 
-        def firstChunkBytes = 1..25 as byte[]
-        def thirdChunkBytes = 51 .. 60 as byte[]
+        def firstChunkBytes = 1..32 as byte[]
+        def lastChunkBytes = 33 .. 57 as byte[]
 
         def sort = new Document('n', 1)
 
         def findQueries = [new Document('files_id', fileInfo.getId()).append('n', new Document('$gte', 0)),
-                           new Document('files_id', fileInfo.getId()).append('n', new Document('$gte', 2))]
+                           new Document('files_id', fileInfo.getId()).append('n', new Document('$gte', 131071))]
         def chunkDocuments =
                 [new Document('files_id', fileInfo.getId()).append('n', 0).append('data', new Binary(firstChunkBytes)),
-                 new Document('files_id', fileInfo.getId()).append('n', 2).append('data', new Binary(thirdChunkBytes))]
+                 new Document('files_id', fileInfo.getId()).append('n', 131071).append('data', new Binary(lastChunkBytes))]
 
         def mongoCursor = Mock(MongoCursor)
         def findIterable = Mock(FindIterable)
@@ -210,10 +211,10 @@ class GridFSDownloadStreamSpecification extends Specification {
         readByte == [16, 17, 18, 19, 20] as byte[]
 
         when:
-        skipResult = downloadStream.skip(35)
+        skipResult = downloadStream.skip(4194272)
 
         then:
-        skipResult == 35L
+        skipResult == 4194272L
         0 * chunksCollection.find(_)
 
         when:
@@ -228,7 +229,7 @@ class GridFSDownloadStreamSpecification extends Specification {
         1 * mongoCursor.next() >> chunkDocuments[1]
 
         then:
-        readByte == [56, 57, 58, 59, 60] as byte[]
+        readByte == [53, 54, 55, 56, 57] as byte[]
 
         when:
         skipResult = downloadStream.skip(1)