Fix a few uses of DeflateStream.Read

The code is assuming it'll always return the requested amount unless it hits EOF, but that's not guaranteed.

Author: stephentoub

src/ImageSharp/Formats/Png/PngDecoderCore.cs

@@ -506,11 +506,15 @@ private void DecodePixelData<TPixel>(DeflateStream compressedStream, ImageFrame<
             while (this.currentRow < this.header.Height)
             {
                 Span<byte> scanlineSpan = this.scanline.GetSpan();
-                int bytesRead = compressedStream.Read(scanlineSpan, this.currentRowBytesRead, this.bytesPerScanline - this.currentRowBytesRead);
-                this.currentRowBytesRead += bytesRead;
-                if (this.currentRowBytesRead < this.bytesPerScanline)
+                while (this.currentRowBytesRead < this.bytesPerScanline)
                 {
-                    return;
+                    int bytesRead = compressedStream.Read(scanlineSpan, this.currentRowBytesRead, this.bytesPerScanline - this.currentRowBytesRead);
+                    if (bytesRead <= 0)
+                    {
+                        return;
+                    }
+
+                    this.currentRowBytesRead += bytesRead;
                 }
 
                 this.currentRowBytesRead = 0;
@@ -577,11 +581,15 @@ private void DecodeInterlacedPixelData<TPixel>(DeflateStream compressedStream, I
 
                 while (this.currentRow < this.header.Height)
                 {
-                    int bytesRead = compressedStream.Read(this.scanline.GetSpan(), this.currentRowBytesRead, bytesPerInterlaceScanline - this.currentRowBytesRead);
-                    this.currentRowBytesRead += bytesRead;
-                    if (this.currentRowBytesRead < bytesPerInterlaceScanline)
+                    while (this.currentRowBytesRead < bytesPerInterlaceScanline)
                     {
-                        return;
+                        int bytesRead = compressedStream.Read(this.scanline.GetSpan(), this.currentRowBytesRead, bytesPerInterlaceScanline - this.currentRowBytesRead);
+                        if (bytesRead <= 0)
+                        {
+                            return;
+                        }
+
+                        this.currentRowBytesRead += bytesRead;
                     }
 
                     this.currentRowBytesRead = 0;

src/ImageSharp/Formats/Tiff/Compression/Decompressors/DeflateTiffCompression.cs

@@ -46,7 +46,18 @@ protected override void Decompress(BufferedReadStream stream, int byteCount, Spa
             {
                 deframeStream.AllocateNewBytes(byteCount, true);
                 DeflateStream dataStream = deframeStream.CompressedStream;
-                dataStream.Read(buffer, 0, buffer.Length);
+
+                int totalRead = 0;
+                while (totalRead < buffer.Length)
+                {
+                    int bytesRead = dataStream.Read(buffer, totalRead, buffer.Length - totalRead);
+                    if (bytesRead <= 0)
+                    {
+                        break;
+                    }
+
+                    totalRead += bytesRead;
+                }
             }
 
             if (this.Predictor == TiffPredictor.Horizontal)