[Skippers] Add stream-based versions of check and transform; convert current versions to use this internally

SabreTools.Helper/Skippers/Skippers.cs

@@ -311,29 +311,42 @@ namespace SabreTools.Helper
 		/// Get the SkipperRule associated with a given file
 		/// </summary>
 		/// <param name="input">Name of the file to be checked</param>
-		/// <param name="skippername">Name of the skipper to be used</param>
+		/// <param name="skipperName">Name of the skipper to be used</param>
 		/// <param name="logger">Logger object for file and console output</param>
 		/// <returns>The SkipperRule that matched the file</returns>
-		public static SkipperRule MatchesSkipper(string input, string skippername, Logger logger)
+		public static SkipperRule MatchesSkipper(string input, string skipperName, Logger logger)
 		{
-			SkipperRule skipperRule = new SkipperRule();
-
 			// If the file doesn't exist, return a blank skipper rule
 			if (!File.Exists(input))
 			{
 				logger.Error("The file '" + input + "' does not exist so it cannot be tested");
-				return skipperRule;
+				return new SkipperRule();
 			}
 
+			return MatchesSkipper(File.OpenRead(input), skipperName, logger);
+		}
+
+		/// <summary>
+		/// Get the SkipperRule associated with a given stream
+		/// </summary>
+		/// <param name="input">Name of the file to be checked</param>
+		/// <param name="skipperName">Name of the skipper to be used</param>
+		/// <param name="logger">Logger object for file and console output</param>
+		/// <param name="keepOpen">True if the underlying stream should be kept open, false otherwise</param>
+		/// <returns>The SkipperRule that matched the file</returns>
+		public static SkipperRule MatchesSkipper(Stream input, string skipperName, Logger logger, bool keepOpen = false)
+		{
+			SkipperRule skipperRule = new SkipperRule();
+
 			// Loop through and find a Skipper that has the right name
 			logger.Log("Beginning search for matching header skip rules");
 			foreach (Skipper skipper in List)
 			{
-				if (String.IsNullOrEmpty(skippername) || (!String.IsNullOrEmpty(skipper.Name) && skippername.ToLowerInvariant() == skipper.Name.ToLowerInvariant()))
+				if (String.IsNullOrEmpty(skipperName) || (!String.IsNullOrEmpty(skipper.Name) && skipperName.ToLowerInvariant() == skipper.Name.ToLowerInvariant()))
 				{
 					// Loop through the rules until one is found that works
-					using (BinaryReader br = new BinaryReader(File.OpenRead(input)))
-					{
+					BinaryReader br = new BinaryReader(input);
+
 					foreach (SkipperRule rule in skipper.Rules)
 					{
 						// Always reset the stream back to the original place
@@ -461,6 +474,13 @@ namespace SabreTools.Helper
 							}
 						}
 
+						// If we're not keeping the stream open, dispose of the binary reader
+						if (!keepOpen)
+						{
+							br.Close();
+							br.Dispose();
+						}
+
 						// If we still have a success, then return this rule
 						if (success)
 						{
@@ -470,7 +490,6 @@ namespace SabreTools.Helper
 					}
 				}
 			}
-			}
 
 			// If we have a blank rule, inform the user
 			if (skipperRule.Tests == null)
@@ -488,7 +507,7 @@ namespace SabreTools.Helper
 		/// <param name="output">Output file name</param>
 		/// <param name="rule">SkipperRule to apply to the file</param>
 		/// <param name="logger">Logger object for file and console output</param>
-		/// <returns></returns>
+		/// <returns>True if the file was transformed properly, false otherwise</returns>
 		public static bool TransformFile(string input, string output, SkipperRule rule, Logger logger)
 		{
 			bool success = true;
@@ -506,23 +525,58 @@ namespace SabreTools.Helper
 				Directory.CreateDirectory(System.IO.Path.GetDirectoryName(output));
 			}
 
+			logger.User("Attempting to apply rule to '" + input + "'");
+			success = TransformStream(File.OpenRead(input), File.OpenWrite(output), rule, logger);
+
+			// If the output file has size 0, delete it
+			if (new FileInfo(output).Length == 0)
+			{
+				try
+				{
+					File.Delete(output);
+				}
+				catch
+				{
+					// Don't log this file deletion error
+				}
+			}
+
+			return success;
+		}
+
+		/// <summary>
+		/// Transform an input stream using the given rule
+		/// </summary>
+		/// <param name="input">Input stream</param>
+		/// <param name="output">Output stream</param>
+		/// <param name="rule">SkipperRule to apply to the stream</param>
+		/// <param name="logger">Logger object for file and console output</param>
+		/// <param name="keepReadOpen">True if the underlying read stream should be kept open, false otherwise</param>
+		/// <param name="keepWriteOpen">True if the underlying write stream should be kept open, false otherwise</param>
+		/// <returns>True if the file was transformed properly, false otherwise</returns>
+		public static bool TransformStream(Stream input, Stream output, SkipperRule rule, Logger logger, bool keepReadOpen = false, bool keepWriteOpen = false)
+		{
+			bool success = true;
+
 			// If the sizes are wrong for the values, fail
-			long extsize = new FileInfo(input).Length;
+			long extsize = input.Length;
 			if ((rule.Operation > HeaderSkipOperation.Bitswap && (extsize % 2) != 0)
 				|| (rule.Operation > HeaderSkipOperation.Byteswap && (extsize % 4) != 0)
 				|| (rule.Operation > HeaderSkipOperation.Bitswap && (rule.StartOffset == null || rule.StartOffset % 2 == 0)))
 			{
-				logger.Error("The file did not have the correct size to be transformed!");
+				logger.Error("The stream did not have the correct size to be transformed!");
 				return false;
 			}
 
 			// Now read the proper part of the file and apply the rule
+			BinaryWriter bw = null;
+			BinaryReader br = null;
 			try
 			{
-				logger.User("Applying found rule to file '" + input + "'");
-				using (BinaryWriter bw = new BinaryWriter(File.OpenWrite(output)))
-				using (BinaryReader br = new BinaryReader(File.OpenRead(input)))
-				{
+				logger.User("Applying found rule to input stream");
+				bw = new BinaryWriter(output);
+				br = new BinaryReader(input);
+
 				// Seek to the beginning offset
 				if (rule.StartOffset == null)
 				{
@@ -604,25 +658,26 @@ namespace SabreTools.Helper
 						bw.Write(buffer[i]);
 					}
 				}
-					
-				}
 			}
 			catch (Exception ex)
 			{
 				logger.Error(ex.ToString());
 				return false;
 			}
-
-			// If the output file has size 0, delete it
-			if (new FileInfo(output).Length == 0)
+			finally
 			{
-				try
+				// If we're not keeping the read stream open, dispose of the binary reader
+				if (!keepReadOpen)
 				{
-					File.Delete(output);
+					br?.Close();
+					br?.Dispose();
 				}
-				catch
+
+				// If we're not keeping the write stream open, dispose of the binary reader
+				if (!keepWriteOpen)
 				{
-					// Don't log this file deletion error
+					bw?.Close();
+					bw?.Dispose();
 				}
 			}