Merge pull request #1079 from MediaBrowser/dev

3.0.5582.0

1 files changed, 223 insertions, 0 deletions

diff --git a/Emby.Drawing/Common/ImageHeader.cs b/Emby.Drawing/Common/ImageHeader.cs
new file mode 100644
index 000000000..b66bd71ea
--- /dev/null
+++ b/Emby.Drawing/Common/ImageHeader.cs
@@ -0,0 +1,223 @@
+using MediaBrowser.Common.IO;
+using MediaBrowser.Model.Drawing;
+using MediaBrowser.Model.Logging;
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+
+namespace Emby.Drawing.Common
+{
+    /// <summary>
+    /// Taken from http://stackoverflow.com/questions/111345/getting-image-dimensions-without-reading-the-entire-file/111349
+    /// http://www.codeproject.com/Articles/35978/Reading-Image-Headers-to-Get-Width-and-Height
+    /// Minor improvements including supporting unsigned 16-bit integers when decoding Jfif and added logic
+    /// to load the image using new Bitmap if reading the headers fails
+    /// </summary>
+    public static class ImageHeader
+    {
+        /// <summary>
+        /// The error message
+        /// </summary>
+        const string ErrorMessage = "Could not recognize image format.";
+
+        /// <summary>
+        /// The image format decoders
+        /// </summary>
+        private static readonly KeyValuePair<byte[], Func<BinaryReader, ImageSize>>[] ImageFormatDecoders = new Dictionary<byte[], Func<BinaryReader, ImageSize>>
+        { 
+            { new byte[] { 0x42, 0x4D }, DecodeBitmap }, 
+            { new byte[] { 0x47, 0x49, 0x46, 0x38, 0x37, 0x61 }, DecodeGif }, 
+            { new byte[] { 0x47, 0x49, 0x46, 0x38, 0x39, 0x61 }, DecodeGif }, 
+            { new byte[] { 0x89, 0x50, 0x4E, 0x47, 0x0D, 0x0A, 0x1A, 0x0A }, DecodePng },
+            { new byte[] { 0xff, 0xd8 }, DecodeJfif }
+
+        }.ToArray();
+
+        private static readonly int MaxMagicBytesLength = ImageFormatDecoders.Select(i => i.Key.Length).OrderByDescending(i => i).First();
+
+        /// <summary>
+        /// Gets the dimensions of an image.
+        /// </summary>
+        /// <param name="path">The path of the image to get the dimensions of.</param>
+        /// <param name="logger">The logger.</param>
+        /// <param name="fileSystem">The file system.</param>
+        /// <returns>The dimensions of the specified image.</returns>
+        /// <exception cref="ArgumentException">The image was of an unrecognised format.</exception>
+        public static ImageSize GetDimensions(string path, ILogger logger, IFileSystem fileSystem)
+        {
+            using (var fs = File.OpenRead(path))
+            {
+                using (var binaryReader = new BinaryReader(fs))
+                {
+                    return GetDimensions(binaryReader);
+                }
+            }
+        }
+
+        /// <summary>
+        /// Gets the dimensions of an image.
+        /// </summary>
+        /// <param name="binaryReader">The binary reader.</param>
+        /// <returns>Size.</returns>
+        /// <exception cref="System.ArgumentException">binaryReader</exception>
+        /// <exception cref="ArgumentException">The image was of an unrecognized format.</exception>
+        private static ImageSize GetDimensions(BinaryReader binaryReader)
+        {
+            var magicBytes = new byte[MaxMagicBytesLength];
+
+            for (var i = 0; i < MaxMagicBytesLength; i += 1)
+            {
+                magicBytes[i] = binaryReader.ReadByte();
+
+                foreach (var kvPair in ImageFormatDecoders)
+                {
+                    if (StartsWith(magicBytes, kvPair.Key))
+                    {
+                        return kvPair.Value(binaryReader);
+                    }
+                }
+            }
+
+            throw new ArgumentException(ErrorMessage, "binaryReader");
+        }
+
+        /// <summary>
+        /// Startses the with.
+        /// </summary>
+        /// <param name="thisBytes">The this bytes.</param>
+        /// <param name="thatBytes">The that bytes.</param>
+        /// <returns><c>true</c> if XXXX, <c>false</c> otherwise</returns>
+        private static bool StartsWith(byte[] thisBytes, byte[] thatBytes)
+        {
+            for (int i = 0; i < thatBytes.Length; i += 1)
+            {
+                if (thisBytes[i] != thatBytes[i])
+                {
+                    return false;
+                }
+            }
+
+            return true;
+        }
+
+        /// <summary>
+        /// Reads the little endian int16.
+        /// </summary>
+        /// <param name="binaryReader">The binary reader.</param>
+        /// <returns>System.Int16.</returns>
+        private static short ReadLittleEndianInt16(BinaryReader binaryReader)
+        {
+            var bytes = new byte[sizeof(short)];
+
+            for (int i = 0; i < sizeof(short); i += 1)
+            {
+                bytes[sizeof(short) - 1 - i] = binaryReader.ReadByte();
+            }
+            return BitConverter.ToInt16(bytes, 0);
+        }
+
+        /// <summary>
+        /// Reads the little endian int32.
+        /// </summary>
+        /// <param name="binaryReader">The binary reader.</param>
+        /// <returns>System.Int32.</returns>
+        private static int ReadLittleEndianInt32(BinaryReader binaryReader)
+        {
+            var bytes = new byte[sizeof(int)];
+            for (int i = 0; i < sizeof(int); i += 1)
+            {
+                bytes[sizeof(int) - 1 - i] = binaryReader.ReadByte();
+            }
+            return BitConverter.ToInt32(bytes, 0);
+        }
+
+        /// <summary>
+        /// Decodes the bitmap.
+        /// </summary>
+        /// <param name="binaryReader">The binary reader.</param>
+        /// <returns>Size.</returns>
+        private static ImageSize DecodeBitmap(BinaryReader binaryReader)
+        {
+            binaryReader.ReadBytes(16);
+            int width = binaryReader.ReadInt32();
+            int height = binaryReader.ReadInt32();
+            return new ImageSize
+            {
+                Width = width,
+                Height = height
+            };
+        }
+
+        /// <summary>
+        /// Decodes the GIF.
+        /// </summary>
+        /// <param name="binaryReader">The binary reader.</param>
+        /// <returns>Size.</returns>
+        private static ImageSize DecodeGif(BinaryReader binaryReader)
+        {
+            int width = binaryReader.ReadInt16();
+            int height = binaryReader.ReadInt16();
+            return new ImageSize
+            {
+                Width = width,
+                Height = height
+            };
+        }
+
+        /// <summary>
+        /// Decodes the PNG.
+        /// </summary>
+        /// <param name="binaryReader">The binary reader.</param>
+        /// <returns>Size.</returns>
+        private static ImageSize DecodePng(BinaryReader binaryReader)
+        {
+            binaryReader.ReadBytes(8);
+            int width = ReadLittleEndianInt32(binaryReader);
+            int height = ReadLittleEndianInt32(binaryReader);
+            return new ImageSize
+            {
+                Width = width,
+                Height = height
+            };
+        }
+
+        /// <summary>
+        /// Decodes the jfif.
+        /// </summary>
+        /// <param name="binaryReader">The binary reader.</param>
+        /// <returns>Size.</returns>
+        /// <exception cref="System.ArgumentException"></exception>
+        private static ImageSize DecodeJfif(BinaryReader binaryReader)
+        {
+            while (binaryReader.ReadByte() == 0xff)
+            {
+                byte marker = binaryReader.ReadByte();
+                short chunkLength = ReadLittleEndianInt16(binaryReader);
+                if (marker == 0xc0)
+                {
+                    binaryReader.ReadByte();
+                    int height = ReadLittleEndianInt16(binaryReader);
+                    int width = ReadLittleEndianInt16(binaryReader);
+                    return new ImageSize
+                    {
+                        Width = width,
+                        Height = height
+                    };
+                }
+
+                if (chunkLength < 0)
+                {
+                    var uchunkLength = (ushort)chunkLength;
+                    binaryReader.ReadBytes(uchunkLength - 2);
+                }
+                else
+                {
+                    binaryReader.ReadBytes(chunkLength - 2);
+                }
+            }
+
+            throw new ArgumentException(ErrorMessage);
+        }
+    }
+}