Improved compression support

.gitignore

@@ -6,6 +6,7 @@
 .pub/
 build/
 packages/
+~packages/
 
 # Or the files created by dart2js.
 *.dart.js

API.md

@@ -159,7 +159,7 @@ If the Cassandra cluster requires authentication but none is supplied or an inco
 
 In order to keep external dependencies to a minimum, the driver does not ship with native implementations for the two compression schemes currently supported by Cassandra (lz4 and snappy).
 
-The driver however allows provides a mechanism for registering a [Codec\<Uint8List, Uint8List>](https://api.dartlang.org/apidocs/channels/stable/dartdoc-viewer/dart:convert.Codec) that implements one of the above compression schemes. This allows you to use a third-party dart package for handling compression if your particular application requires it.
+The driver however allows provides a mechanism for registering a [Codec\<Uint8List, Uint8List>](https://api.dartlang.org/apidocs/channels/stable/dartdoc-viewer/dart:convert.Codec) that implements one of the above compression schemes. This allows you to use a third-party dart package (e.g [dart_lz4](https://github.com/achilleasa/dart_lz4) native extension) for handling compression if your particular application requires it.
 
 To use this feature you need to invoke the public method ```registerCodec(String, Codec<Object, Uint8List>)``` and specify one of the [Compression](https://github.com/achilleasa/dart_cassandra_cql/blob/master/lib/src/types/enums/compression.dart) enum **values** (e.g. ```Compression.LZ4.value```) as the first argument and a class instance implementing ```Codec<Uint8, Uint8>``` as the second argument.
 

CHANGELOG.md

@@ -1,3 +1,8 @@
+## 0.1.3 (December 20, 2014)
+
+Improved support for compression codecs
+Driver is now compatible with [dart_lz4](https://github.com/achilleasa/dart_lz4)
+
 ## 0.1.2 (December 6, 2014)
 
 Renamed lib/driver to lib/src so that docgen works

lib/src/protocol/frame/frame_decompressor.dart

@@ -22,10 +22,9 @@ class FrameDecompressor {
         }
 
         // Decompress and replace body data. According to the spec, if the compression algorithm is LZ4
-        // then we need to skip the first 4 bytes which signify the uncompressed length
-        Uint8List bodyData = _compression == Compression.LZ4
-                             ? new Uint8List.view(frame.body.buffer, 4, frame.body.lengthInBytes - 4)
-                             : new Uint8List.view(frame.body.buffer, 0, frame.body.lengthInBytes);
+        // then the first four bytes of the payload should include its decompressed length so compliant
+        // LZ4 codecs should expect this.
+        Uint8List bodyData = new Uint8List.view(frame.body.buffer, 0, frame.body.lengthInBytes);
 
         // Generate uncompressed frame
         bodyData = compressionCodec.decode(bodyData);

lib/src/protocol/frame/frame_writer.dart

@@ -45,13 +45,8 @@ class FrameWriter {
       }
 
       // Replace writer blocks with compressed output and enable the compression flag for the header
-      // According to the protocol spec, when using LZ4 we need to prepend a 4-byte int with the
-      // uncompressed data length before the payload
       _header.flags |= HeaderFlag.COMPRESSION.value;
       _typeEncoder.writer.clear();
-      if (compression == Compression.LZ4) {
-        _typeEncoder.writeUInt32(uncompressedLen);
-      }
       _typeEncoder.writer.addLast(compressedData);
     }