Optimize compression/decompression and add tests

QRCoder/QRCodeData.cs

@@ -59,42 +59,44 @@ public QRCodeData(string pathToRawData, Compression compressMode) : this(File.Re
     /// <param name="compressMode">The compression mode used for the raw data.</param>
     public QRCodeData(byte[] rawData, Compression compressMode)
     {
-        var bytes = new List<byte>(rawData);
-
         //Decompress
         if (compressMode == Compression.Deflate)
         {
-            using var input = new MemoryStream(bytes.ToArray());
+            using var input = new MemoryStream(rawData);
             using var output = new MemoryStream();
             using (var dstream = new DeflateStream(input, CompressionMode.Decompress))
             {
                 dstream.CopyTo(output);
             }
-            bytes = new List<byte>(output.ToArray());
+            rawData = output.ToArray();
         }
         else if (compressMode == Compression.GZip)
         {
-            using var input = new MemoryStream(bytes.ToArray());
+            using var input = new MemoryStream(rawData);
             using var output = new MemoryStream();
             using (var dstream = new GZipStream(input, CompressionMode.Decompress))
             {
                 dstream.CopyTo(output);
             }
-            bytes = new List<byte>(output.ToArray());
+            rawData = output.ToArray();
         }
 
-        if (bytes[0] != 0x51 || bytes[1] != 0x52 || bytes[2] != 0x52)
+        var count = rawData.Length;
+
+        if (count < 5)
+            throw new Exception("Invalid raw data file. File too short.");
+        if (rawData[0] != 0x51 || rawData[1] != 0x52 || rawData[2] != 0x52)
             throw new Exception("Invalid raw data file. Filetype doesn't match \"QRR\".");
 
         //Set QR code version
-        var sideLen = (int)bytes[4];
-        bytes.RemoveRange(0, 5);
+        var sideLen = (int)rawData[4];
         Version = (sideLen - 21 - 8) / 4 + 1;
 
         //Unpack
-        var modules = new Queue<bool>(8 * bytes.Count);
-        foreach (var b in bytes)
+        var modules = new Queue<bool>(8 * (count - 5));
+        for (int j = 5; j < count; j++)
         {
+            var b = rawData[j];
             for (int i = 7; i >= 0; i--)
             {
                 modules.Enqueue((b & (1 << i)) != 0);
@@ -111,7 +113,6 @@ public QRCodeData(byte[] rawData, Compression compressMode)
                 ModuleMatrix[y][x] = modules.Dequeue();
             }
         }
-
     }
 
     /// <summary>
@@ -121,60 +122,64 @@ public QRCodeData(byte[] rawData, Compression compressMode)
     /// <returns>Returns the raw data of the QR code as a byte array.</returns>
     public byte[] GetRawData(Compression compressMode)
     {
-        var bytes = new List<byte>();
-
-        //Add header - signature ("QRR")
-        bytes.AddRange(new byte[] { 0x51, 0x52, 0x52, 0x00 });
-
-        //Add header - rowsize
-        bytes.Add((byte)ModuleMatrix.Count);
+        using var output = new MemoryStream();
+        Stream targetStream = output;
+        DeflateStream? deflateStream = null;
+        GZipStream? gzipStream = null;
 
-        //Build data queue
-        var dataQueue = new Queue<int>();
-        foreach (var row in ModuleMatrix)
+        //Set up compression stream if needed
+        if (compressMode == Compression.Deflate)
         {
-            foreach (var module in row)
-            {
-                dataQueue.Enqueue((bool)module ? 1 : 0);
-            }
+            deflateStream = new DeflateStream(output, CompressionMode.Compress, true);
+            targetStream = deflateStream;
         }
-        for (int i = 0; i < 8 - (ModuleMatrix.Count * ModuleMatrix.Count) % 8; i++)
+        else if (compressMode == Compression.GZip)
         {
-            dataQueue.Enqueue(0);
+            gzipStream = new GZipStream(output, CompressionMode.Compress, true);
+            targetStream = gzipStream;
         }
 
-        //Process queue
-        while (dataQueue.Count > 0)
+        try
         {
-            byte b = 0;
-            for (int i = 7; i >= 0; i--)
+            //Add header - signature ("QRR")
+            targetStream.Write(new byte[] { 0x51, 0x52, 0x52, 0x00 }, 0, 4);
+
+            //Add header - rowsize
+            targetStream.WriteByte((byte)ModuleMatrix.Count);
+
+            //Build data queue
+            var dataQueue = new Queue<int>();
+            foreach (var row in ModuleMatrix)
             {
-                b += (byte)(dataQueue.Dequeue() << i);
+                foreach (var module in row)
+                {
+                    dataQueue.Enqueue((bool)module ? 1 : 0);
+                }
+            }
+            for (int i = 0; i < 8 - (ModuleMatrix.Count * ModuleMatrix.Count) % 8; i++)
+            {
+                dataQueue.Enqueue(0);
             }
-            bytes.Add(b);
-        }
-        var rawData = bytes.ToArray();
 
-        //Compress stream (optional)
-        if (compressMode == Compression.Deflate)
-        {
-            using var output = new MemoryStream();
-            using (var dstream = new DeflateStream(output, CompressionMode.Compress))
+            //Process queue
+            while (dataQueue.Count > 0)
             {
-                dstream.Write(rawData, 0, rawData.Length);
+                byte b = 0;
+                for (int i = 7; i >= 0; i--)
+                {
+                    b += (byte)(dataQueue.Dequeue() << i);
+                }
+                targetStream.WriteByte(b);
             }
-            rawData = output.ToArray();
         }
-        else if (compressMode == Compression.GZip)
+        finally
         {
-            using var output = new MemoryStream();
-            using (var gzipStream = new GZipStream(output, CompressionMode.Compress, true))
-            {
-                gzipStream.Write(rawData, 0, rawData.Length);
-            }
-            rawData = output.ToArray();
+            //Close compression streams to flush data
+            deflateStream?.Dispose();
+            gzipStream?.Dispose();
         }
-        return rawData;
+
+        return output.ToArray();
     }
 
     /// <summary>

QRCoderTests/QRGeneratorTests.cs

@@ -622,6 +622,30 @@ public SamplePayload(string data, QRCodeGenerator.ECCLevel eccLevel)
 
         public override string ToString() => _data;
     }
+
+#if !NETFRAMEWORK // [Theory] is not supported in xunit < 2.0.0
+    [Theory]
+    [InlineData(QRCodeData.Compression.Uncompressed)]
+    [InlineData(QRCodeData.Compression.Deflate)]
+    [InlineData(QRCodeData.Compression.GZip)]
+    public void can_save_and_load_qrcode_data(QRCodeData.Compression compressionMode)
+    {
+        // Arrange - Create a QR code
+        var gen = new QRCodeGenerator();
+        var originalQrData = gen.CreateQrCode("https://github.com/Shane32/QRCoder", ECCLevel.H);
+        var originalMatrix = string.Join("", originalQrData.ModuleMatrix.Select(x => x.ToBitString()).ToArray());
+
+        // Act - Get raw data and reload it
+        var rawData = originalQrData.GetRawData(compressionMode);
+        var reloadedQrData = new QRCodeData(rawData, compressionMode);
+        var reloadedMatrix = string.Join("", reloadedQrData.ModuleMatrix.Select(x => x.ToBitString()).ToArray());
+
+        // Assert - Verify the data matches
+        reloadedQrData.Version.ShouldBe(originalQrData.Version);
+        reloadedQrData.ModuleMatrix.Count.ShouldBe(originalQrData.ModuleMatrix.Count);
+        reloadedMatrix.ShouldBe(originalMatrix);
+    }
+#endif
 }
 
 public static class ExtensionMethods