diff --git a/lib/mongoid-grid_fs.rb b/lib/mongoid-grid_fs.rb
index e12e475..fe974ce 100644
--- a/lib/mongoid-grid_fs.rb
+++ b/lib/mongoid-grid_fs.rb
@@ -1,7 +1,7 @@
 ##
 #
   class GridFS
-    const_set :Version, '1.1.2'
+    const_set :Version, '1.2.0'
 
     class << GridFS
       def version
@@ -185,7 +185,7 @@
               attributes[:contentType] ||=
                 GridFS.extract_content_type(filename) || file.contentType
 
-            while((buf = io.read(chunkSize)))
+            GridFS.chunking(io, chunkSize) do |buf|
               md5 << buf
               length += buf.size
               chunk = file.chunks.build
@@ -422,6 +422,27 @@
       end
     end
 
+    def GridFS.chunking(io, chunk_size, &block)
+      if io.method(:read).arity == 0
+        data = io.read
+        i = 0
+        loop do
+          offset = i * chunk_size
+          length = i + chunk_size < data.size ? chunk_size : data.size - offset
+
+          break if offset >= data.size
+
+          buf = data[offset, length]
+          block.call(buf)
+          i += 1
+        end
+      else
+        while((buf = io.read(chunk_size)))
+          block.call(buf)
+        end
+      end
+    end
+
     def GridFS.rewind(io, &block)
       begin
         pos = io.pos
diff --git a/mongoid-grid_fs.gemspec b/mongoid-grid_fs.gemspec
index e389c8f..d7c7915 100644
--- a/mongoid-grid_fs.gemspec
+++ b/mongoid-grid_fs.gemspec
@@ -3,7 +3,7 @@
 
 Gem::Specification::new do |spec|
   spec.name = "mongoid-grid_fs"
-  spec.version = "1.1.2"
+  spec.version = "1.2.0"
   spec.platform = Gem::Platform::RUBY
   spec.summary = "mongoid-grid_fs"
   spec.description = "a mongoid 3/moped compatible implementation of the grid_fs specification"