From 58a37ddccd5b23b87ee236b44f65337ec0cedcc8 Mon Sep 17 00:00:00 2001
From: Pacien TRAN-GIRARD
Date: Thu, 5 May 2016 22:44:54 +0200
Subject: Factorize byte compression

---
 src/ch/epfl/xblast/server/GameStateSerializer.java | 20 +++++++++++---------
 1 file changed, 11 insertions(+), 9 deletions(-)

diff --git a/src/ch/epfl/xblast/server/GameStateSerializer.java b/src/ch/epfl/xblast/server/GameStateSerializer.java
index a471962..a24ed95 100644
--- a/src/ch/epfl/xblast/server/GameStateSerializer.java
+++ b/src/ch/epfl/xblast/server/GameStateSerializer.java
@@ -33,7 +33,7 @@ public final class GameStateSerializer {
      * @return a list of byte corresponding to the blocks' images
      */
     private static List<Byte> serializeBoard(BoardPainter painter, Board board) {
-        return RunLengthEncoder.encode(Cell.SPIRAL_ORDER.stream()
+        return Collections.unmodifiableList(Cell.SPIRAL_ORDER.stream()
                 .map(c -> painter.byteForCell(board, c))
                 .collect(Collectors.toList()));
     }
@@ -81,7 +81,7 @@ public final class GameStateSerializer {
      * @return the serialized explosions
      */
     private static List<Byte> serializeExplosions(Map<Cell, Bomb> bombedCells, Set<Cell> blastedCells, Board board) {
-        return RunLengthEncoder.encode(Cell.ROW_MAJOR_ORDER.stream()
+        return Collections.unmodifiableList(Cell.ROW_MAJOR_ORDER.stream()
                 .map(c -> serializeExplosion(bombedCells, blastedCells, c, board))
                 .collect(Collectors.toList()));
     }
@@ -125,13 +125,15 @@ public final class GameStateSerializer {
     }
 
     /**
-     * Prepends its size to a Byte List.
+     * Compresses and returns the given byte list using the run-length encoding.
+     * The length of the compressed sequence is prepended to the result.
      *
-     * @param l Byte List to be prefixed
-     * @return the Byte List prefixed with its size
+     * @param l Byte List to be compressed
+     * @return the compressed byte sequence prefixed by its size
      */
-    private static List<Byte> prependSize(List<Byte> l) {
-        return Lists.prepended(l, (byte) l.size());
+    private static List<Byte> compress(List<Byte> l) {
+        List<Byte> rle = RunLengthEncoder.encode(l);
+        return Lists.prepended(rle, (byte) rle.size());
     }
 
     /**
@@ -143,8 +145,8 @@ public final class GameStateSerializer {
      */
     public static List<Byte> serialize(BoardPainter bp, GameState gs) {
         return Collections.unmodifiableList(Stream.of(
-                prependSize(serializeBoard(bp, gs.board())),
-                prependSize(serializeExplosions(gs.bombedCells(), gs.blastedCells(), gs.board())),
+                compress(serializeBoard(bp, gs.board())),
+                compress(serializeExplosions(gs.bombedCells(), gs.blastedCells(), gs.board())),
                 serializePlayers(gs.players(), gs.ticks()),
                 serializeRemainingTime(gs.remainingTime())
         ).flatMap(List::stream).collect(Collectors.toList()));
-- 
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