Unsure to merge: Compress blocks and txs as well

Libplanet.Tests/Store/CompressedDefaultStoreTest.cs

@@ -0,0 +1,12 @@
+using Xunit.Abstractions;
+
+namespace Libplanet.Tests.Store
+{
+    public class CompressedDefaultStoreTest : DefaultStoreTest
+    {
+        public CompressedDefaultStoreTest(ITestOutputHelper testOutputHelper)
+            : base(testOutputHelper, compress: true)
+        {
+        }
+    }
+}

Libplanet.Tests/Store/DefaultStoreFixture.cs

@@ -6,7 +6,7 @@ namespace Libplanet.Tests.Store
 {
     public class DefaultStoreFixture : StoreFixture, IDisposable
     {
-        public DefaultStoreFixture(bool memory = false)
+        public DefaultStoreFixture(bool memory = false, bool compress = false)
         {
             if (memory)
             {
@@ -20,7 +20,12 @@ public DefaultStoreFixture(bool memory = false)
                 );
             }
 
-            Store = new DefaultStore(Path, blockCacheSize: 2, txCacheSize: 2);
+            Store = new DefaultStore(
+                Path,
+                compress: compress,
+                blockCacheSize: 2,
+                txCacheSize: 2
+            );
         }
 
         public string Path { get; }

Libplanet.Tests/Store/DefaultStoreTest.cs

@@ -13,10 +13,10 @@ public class DefaultStoreTest : StoreTest, IDisposable
     {
         private readonly DefaultStoreFixture _fx;
 
-        public DefaultStoreTest(ITestOutputHelper testOutputHelper)
+        public DefaultStoreTest(ITestOutputHelper testOutputHelper, bool compress = false)
         {
             TestOutputHelper = testOutputHelper;
-            Fx = _fx = new DefaultStoreFixture();
+            Fx = _fx = new DefaultStoreFixture(compress: compress);
         }
 
         public void Dispose()

Libplanet/Store/DefaultStore.cs

@@ -385,6 +385,14 @@ public override Transaction<T> GetTransaction<T>(TxId txid)
                 return null;
             }
 
+            if (_compress)
+            {
+                using (var inputBuffer = new MemoryStream(bytes))
+                {
+                    bytes = Decompress(inputBuffer);
+                }
+            }
+
             Transaction<T> tx = Transaction<T>.Deserialize(bytes);
             _txCache.AddOrUpdate(txid, tx);
             return tx;
@@ -819,28 +827,73 @@ internal static string FormatChainId(Guid chainId) =>
                 return null;
             }
 
-            RawBlock rawBlock;
+            IValue value;
             try
             {
-                var value = new Codec().Decode(_blocks.ReadAllBytes(path));
-                if (!(value is Bencodex.Types.Dictionary dict))
+                byte[] bytes;
+                if (_compress)
                 {
-                    throw new DecodingException(
-                        $"Expected {typeof(Bencodex.Types.Dictionary)} but " +
-                        $"{value.GetType()}");
+                    using (var f = _blocks.OpenFile(path, System.IO.FileMode.Open, FileAccess.Read))
+                    {
+                        bytes = Decompress(f);
+                    }
+                }
+                else
+                {
+                    bytes = _blocks.ReadAllBytes(path);
                 }
 
-                rawBlock = new RawBlock(dict);
+                value = new Codec().Decode(bytes);
             }
             catch (FileNotFoundException)
             {
                 return null;
             }
 
+            if (!(value is Bencodex.Types.Dictionary dict))
+            {
+                throw new DecodingException(
+                    $"Expected {typeof(Bencodex.Types.Dictionary)} but " +
+                    $"{value.GetType()}");
+            }
+
+            RawBlock rawBlock = new RawBlock(dict);
             _blockCache.AddOrUpdate(blockHash, rawBlock);
             return rawBlock;
         }
 
+        private static byte[] CompressBytes(byte[] input)
+        {
+            using (var buffer = new MemoryStream())
+            using (var deflate = new DeflateStream(buffer, CompressionLevel.Fastest, true))
+            {
+                deflate.Write(input, 0, input.Length);
+                deflate.Flush();
+                buffer.Flush();
+                int length = (int)buffer.Position;
+                var output = new byte[length];
+                buffer.Seek(0, SeekOrigin.Begin);
+                buffer.Read(output, 0, output.Length);
+                return output;
+            }
+        }
+
+        private static byte[] Decompress(Stream inputBuffer)
+        {
+            using (var outputBuffer = new MemoryStream())
+            using (var deflate = new DeflateStream(inputBuffer, CompressionMode.Decompress))
+            {
+                deflate.CopyTo(outputBuffer);
+                deflate.Flush();
+                outputBuffer.Flush();
+                int length = (int)outputBuffer.Position;
+                var output = new byte[length];
+                outputBuffer.Seek(0, SeekOrigin.Begin);
+                outputBuffer.Read(output, 0, output.Length);
+                return output;
+            }
+        }
+
         private static void CreateDirectoryRecursively(IFileSystem fs, UPath path)
         {
             if (!fs.DirectoryExists(path))
@@ -862,6 +915,11 @@ private void WriteContentAddressableFile(IFileSystem fs, UPath path, byte[] cont
                 return;
             }
 
+            if (_compress)
+            {
+                contents = CompressBytes(contents);
+            }
+
             // For atomicity, writes bytes into an intermediate temp file,
             // and then renames it to the final destination.
             UPath tmpPath = dirPath / $".{Guid.NewGuid():N}.tmp";