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

SabreTools.Helper/Skippers/Skippers.cs

@@ -311,162 +311,181 @@ 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)
 					{
-						foreach (SkipperRule rule in skipper.Rules)
+						// Always reset the stream back to the original place
+						br.BaseStream.Seek(0, SeekOrigin.Begin);
+
+						// For each rule, make sure it passes each test
+						bool success = true;
+						foreach (SkipperTest test in rule.Tests)
 						{
-							// Always reset the stream back to the original place
-							br.BaseStream.Seek(0, SeekOrigin.Begin);
-
-							// For each rule, make sure it passes each test
-							bool success = true;
-							foreach (SkipperTest test in rule.Tests)
+							bool result = true;
+							switch (test.Type)
 							{
-								bool result = true;
-								switch (test.Type)
-								{
-									case HeaderSkipTest.Data:
-										// First seek to the correct position
-										if (test.Offset == null)
-										{
-											br.BaseStream.Seek(0, SeekOrigin.End);
-										}
-										else if (test.Offset > 0 && test.Offset <= br.BaseStream.Length)
-										{
-											br.BaseStream.Seek((long)test.Offset, SeekOrigin.Begin);
-										}
-										else if (test.Offset < 0 && Math.Abs((long)test.Offset) <= br.BaseStream.Length)
-										{
-											br.BaseStream.Seek((long)test.Offset, SeekOrigin.End);
-										}
+								case HeaderSkipTest.Data:
+									// First seek to the correct position
+									if (test.Offset == null)
+									{
+										br.BaseStream.Seek(0, SeekOrigin.End);
+									}
+									else if (test.Offset > 0 && test.Offset <= br.BaseStream.Length)
+									{
+										br.BaseStream.Seek((long)test.Offset, SeekOrigin.Begin);
+									}
+									else if (test.Offset < 0 && Math.Abs((long)test.Offset) <= br.BaseStream.Length)
+									{
+										br.BaseStream.Seek((long)test.Offset, SeekOrigin.End);
+									}
 
-										// Then read and compare bytewise
-										result = true;
-										for (int i = 0; i < test.Value.Length; i++)
+									// Then read and compare bytewise
+									result = true;
+									for (int i = 0; i < test.Value.Length; i++)
+									{
+										try
 										{
-											try
-											{
-												if (br.ReadByte() != test.Value[i])
-												{
-													result = false;
-													break;
-												}
-											}
-											catch
+											if (br.ReadByte() != test.Value[i])
 											{
 												result = false;
 												break;
 											}
 										}
-
-										// Return if the expected and actual results match
-										success &= (result == test.Result);
-										break;
-									case HeaderSkipTest.Or:
-									case HeaderSkipTest.Xor:
-									case HeaderSkipTest.And:
-										// First seek to the correct position
-										if (test.Offset == null)
-										{
-											br.BaseStream.Seek(0, SeekOrigin.End);
-										}
-										else if (test.Offset > 0 && test.Offset <= br.BaseStream.Length)
-										{
-											br.BaseStream.Seek((long)test.Offset, SeekOrigin.Begin);
-										}
-										else if (test.Offset < 0 && Math.Abs((long)test.Offset) <= br.BaseStream.Length)
-										{
-											br.BaseStream.Seek((long)test.Offset, SeekOrigin.End);
-										}
-
-										result = true;
-										try
-										{
-											// Then apply the mask if it exists
-											byte[] read = br.ReadBytes(test.Mask.Length);
-											byte[] masked = new byte[test.Mask.Length];
-											for (int i = 0; i < read.Length; i++)
-											{
-												masked[i] = (byte)(test.Type == HeaderSkipTest.And ? read[i] & test.Mask[i] :
-													(test.Type == HeaderSkipTest.Or ? read[i] | test.Mask[i] : read[i] ^ test.Mask[i])
-												);
-											}
-
-											// Finally, compare it against the value
-											for (int i = 0; i < test.Value.Length; i++)
-											{
-												if (masked[i] != test.Value[i])
-												{
-													result = false;
-													break;
-												}
-											}
-										}
 										catch
 										{
 											result = false;
+											break;
+										}
+									}
+
+									// Return if the expected and actual results match
+									success &= (result == test.Result);
+									break;
+								case HeaderSkipTest.Or:
+								case HeaderSkipTest.Xor:
+								case HeaderSkipTest.And:
+									// First seek to the correct position
+									if (test.Offset == null)
+									{
+										br.BaseStream.Seek(0, SeekOrigin.End);
+									}
+									else if (test.Offset > 0 && test.Offset <= br.BaseStream.Length)
+									{
+										br.BaseStream.Seek((long)test.Offset, SeekOrigin.Begin);
+									}
+									else if (test.Offset < 0 && Math.Abs((long)test.Offset) <= br.BaseStream.Length)
+									{
+										br.BaseStream.Seek((long)test.Offset, SeekOrigin.End);
+									}
+
+									result = true;
+									try
+									{
+										// Then apply the mask if it exists
+										byte[] read = br.ReadBytes(test.Mask.Length);
+										byte[] masked = new byte[test.Mask.Length];
+										for (int i = 0; i < read.Length; i++)
+										{
+											masked[i] = (byte)(test.Type == HeaderSkipTest.And ? read[i] & test.Mask[i] :
+												(test.Type == HeaderSkipTest.Or ? read[i] | test.Mask[i] : read[i] ^ test.Mask[i])
+											);
 										}
 
-										// Return if the expected and actual results match
-										success &= (result == test.Result);
-										break;
-									case HeaderSkipTest.File:
-										// First get the file size from stream
-										long size = br.BaseStream.Length;
+										// Finally, compare it against the value
+										for (int i = 0; i < test.Value.Length; i++)
+										{
+											if (masked[i] != test.Value[i])
+											{
+												result = false;
+												break;
+											}
+										}
+									}
+									catch
+									{
+										result = false;
+									}
 
-										// If we have a null size, check that the size is a power of 2
-										result = true;
-										if (test.Size == null)
-										{
-											// http://stackoverflow.com/questions/600293/how-to-check-if-a-number-is-a-power-of-2
-											result = (((ulong)size & ((ulong)size - 1)) == 0);
-										}
-										else if (test.Operator == HeaderSkipTestFileOperator.Less)
-										{
-											result = (size < test.Size);
-										}
-										else if (test.Operator == HeaderSkipTestFileOperator.Greater)
-										{
-											result = (size > test.Size);
-										}
-										else if (test.Operator == HeaderSkipTestFileOperator.Equal)
-										{
-											result = (size == test.Size);
-										}
+									// Return if the expected and actual results match
+									success &= (result == test.Result);
+									break;
+								case HeaderSkipTest.File:
+									// First get the file size from stream
+									long size = br.BaseStream.Length;
 
-										// Return if the expected and actual results match
-										success &= (result == test.Result);
-										break;
-								}
+									// If we have a null size, check that the size is a power of 2
+									result = true;
+									if (test.Size == null)
+									{
+										// http://stackoverflow.com/questions/600293/how-to-check-if-a-number-is-a-power-of-2
+										result = (((ulong)size & ((ulong)size - 1)) == 0);
+									}
+									else if (test.Operator == HeaderSkipTestFileOperator.Less)
+									{
+										result = (size < test.Size);
+									}
+									else if (test.Operator == HeaderSkipTestFileOperator.Greater)
+									{
+										result = (size > test.Size);
+									}
+									else if (test.Operator == HeaderSkipTestFileOperator.Equal)
+									{
+										result = (size == test.Size);
+									}
+
+									// Return if the expected and actual results match
+									success &= (result == test.Result);
+									break;
 							}
+						}
 
-							// If we still have a success, then return this rule
-							if (success)
-							{
-								logger.User(" Matching rule found!");
-								return rule;
-							}
+						// 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)
+						{
+							logger.User(" Matching rule found!");
+							return rule;
 						}
 					}
 				}
@@ -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;
@@ -506,112 +525,8 @@ namespace SabreTools.Helper
 				Directory.CreateDirectory(System.IO.Path.GetDirectoryName(output));
 			}
 
-			// If the sizes are wrong for the values, fail
-			long extsize = new FileInfo(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!");
-				return false;
-			}
-
-			// Now read the proper part of the file and apply the rule
-			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)))
-				{
-					// Seek to the beginning offset
-					if (rule.StartOffset == null)
-					{
-						success = false;
-					}
-					else if (Math.Abs((long)rule.StartOffset) > br.BaseStream.Length)
-					{
-						success = false;
-					}
-					else if (rule.StartOffset > 0)
-					{
-						br.BaseStream.Seek((long)rule.StartOffset, SeekOrigin.Begin);
-					}
-					else if (rule.StartOffset < 0)
-					{
-						br.BaseStream.Seek((long)rule.StartOffset, SeekOrigin.End);
-					}
-
-					// Then read and apply the operation as you go
-					if (success)
-					{
-						byte[] buffer = new byte[4];
-						int pos = 0;
-						while (br.BaseStream.Position < (rule.EndOffset != null ? rule.EndOffset : br.BaseStream.Length)
-							&& br.BaseStream.Position < br.BaseStream.Length)
-						{
-							byte b = br.ReadByte();
-							switch (rule.Operation)
-							{
-								case HeaderSkipOperation.Bitswap:
-									// http://stackoverflow.com/questions/3587826/is-there-a-built-in-function-to-reverse-bit-order
-									uint r = b;
-									int s = 7;
-									for (b >>= 1; b != 0; b >>= 1)
-									{
-										r <<= 1;
-										r |= (byte)(b & 1);
-										s--;
-									}
-									r <<= s;
-									buffer[pos] = (byte)r;
-									break;
-								case HeaderSkipOperation.Byteswap:
-									if (pos % 2 == 1)
-									{
-										buffer[pos - 1] = b;
-									}
-									if (pos % 2 == 0)
-									{
-										buffer[pos + 1] = b;
-									}
-									break;
-								case HeaderSkipOperation.Wordswap:
-									buffer[3 - pos] = b;
-									break;
-								case HeaderSkipOperation.WordByteswap:
-									buffer[(pos + 2) % 4] = b;
-									break;
-								case HeaderSkipOperation.None:
-								default:
-									buffer[pos] = b;
-									break;
-							}
-
-							// Set the buffer position to default write to
-							pos = (pos + 1) % 4;
-
-							// If we filled a buffer, flush to the stream
-							if (pos == 0)
-							{
-								bw.Write(buffer);
-								bw.Flush();
-								buffer = new byte[4];
-							}
-						}
-						// If there's anything more in the buffer, write only the left bits
-						for (int i = 0; i < pos; i++)
-						{
-							bw.Write(buffer[i]);
-						}
-					}
-					
-				}
-			}
-			catch (Exception ex)
-			{
-				logger.Error(ex.ToString());
-				return false;
-			}
+			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)
@@ -629,6 +544,146 @@ namespace SabreTools.Helper
 			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 = 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 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 input stream");
+				bw = new BinaryWriter(output);
+				br = new BinaryReader(input);
+
+				// Seek to the beginning offset
+				if (rule.StartOffset == null)
+				{
+					success = false;
+				}
+				else if (Math.Abs((long)rule.StartOffset) > br.BaseStream.Length)
+				{
+					success = false;
+				}
+				else if (rule.StartOffset > 0)
+				{
+					br.BaseStream.Seek((long)rule.StartOffset, SeekOrigin.Begin);
+				}
+				else if (rule.StartOffset < 0)
+				{
+					br.BaseStream.Seek((long)rule.StartOffset, SeekOrigin.End);
+				}
+
+				// Then read and apply the operation as you go
+				if (success)
+				{
+					byte[] buffer = new byte[4];
+					int pos = 0;
+					while (br.BaseStream.Position < (rule.EndOffset != null ? rule.EndOffset : br.BaseStream.Length)
+						&& br.BaseStream.Position < br.BaseStream.Length)
+					{
+						byte b = br.ReadByte();
+						switch (rule.Operation)
+						{
+							case HeaderSkipOperation.Bitswap:
+								// http://stackoverflow.com/questions/3587826/is-there-a-built-in-function-to-reverse-bit-order
+								uint r = b;
+								int s = 7;
+								for (b >>= 1; b != 0; b >>= 1)
+								{
+									r <<= 1;
+									r |= (byte)(b & 1);
+									s--;
+								}
+								r <<= s;
+								buffer[pos] = (byte)r;
+								break;
+							case HeaderSkipOperation.Byteswap:
+								if (pos % 2 == 1)
+								{
+									buffer[pos - 1] = b;
+								}
+								if (pos % 2 == 0)
+								{
+									buffer[pos + 1] = b;
+								}
+								break;
+							case HeaderSkipOperation.Wordswap:
+								buffer[3 - pos] = b;
+								break;
+							case HeaderSkipOperation.WordByteswap:
+								buffer[(pos + 2) % 4] = b;
+								break;
+							case HeaderSkipOperation.None:
+							default:
+								buffer[pos] = b;
+								break;
+						}
+
+						// Set the buffer position to default write to
+						pos = (pos + 1) % 4;
+
+						// If we filled a buffer, flush to the stream
+						if (pos == 0)
+						{
+							bw.Write(buffer);
+							bw.Flush();
+							buffer = new byte[4];
+						}
+					}
+					// If there's anything more in the buffer, write only the left bits
+					for (int i = 0; i < pos; i++)
+					{
+						bw.Write(buffer[i]);
+					}
+				}
+			}
+			catch (Exception ex)
+			{
+				logger.Error(ex.ToString());
+				return false;
+			}
+			finally
+			{
+				// If we're not keeping the read stream open, dispose of the binary reader
+				if (!keepReadOpen)
+				{
+					br?.Close();
+					br?.Dispose();
+				}
+
+				// If we're not keeping the write stream open, dispose of the binary reader
+				if (!keepWriteOpen)
+				{
+					bw?.Close();
+					bw?.Dispose();
+				}
+			}
+
+			return success;
+		}
+
 		#endregion
 
 		#region Header Skips (old)