Bugfix for quoted-printable and "Q" encoding

Improved QDecode/QPDecode methods to address several issues, see smiley22#15

MessageBuilder.cs

@@ -257,22 +257,24 @@ internal static class MessageBuilder {
 				Util.GetEncoding(part.Parameters["Charset"]) : Encoding.ASCII;
 			// decode content if it was encoded
 			byte[] bytes;
-			switch (part.Encoding) {
-				case ContentTransferEncoding.QuotedPrintable:
-					bytes = encoding.GetBytes(Util.QPDecode(content, encoding));
-					break;
-				case ContentTransferEncoding.Base64:
-					try {
+			try {
+				switch (part.Encoding) {
+					case ContentTransferEncoding.QuotedPrintable:
+						bytes = encoding.GetBytes(Util.QPDecode(content, encoding));
+						break;
+					case ContentTransferEncoding.Base64:
 						bytes = Util.Base64Decode(content);
-					} catch {
-						// If it's not a valid Base64 string just leave the data as is
+						break;
+					default:
 						bytes = Encoding.ASCII.GetBytes(content);
-					}
-					break;
-				default:
-					bytes = Encoding.ASCII.GetBytes(content);
-					break;
+						break;
+				}
+			} catch {
+				// If it's not a valid Base64 or quoted-printable encoded string
+				// just leave the data as is
+				bytes = Encoding.ASCII.GetBytes(content);
 			}
+
 			// If the MailMessage's Body fields haven't been initialized yet, put it there.
 			// Some weird (i.e. spam) mails like to omit content-types so don't check for
 			// that here and just assume it's text.

Properties/AssemblyInfo.cs

@@ -32,5 +32,5 @@
 // You can specify all the values or you can default the Build and Revision Numbers 
 // by using the '*' as shown below:
 // [assembly: AssemblyVersion("1.0.*")]
-[assembly: AssemblyVersion("2.5.*")]
-[assembly: AssemblyFileVersion("2.5.0.0")]
+[assembly: AssemblyVersion("2.6.*")]
+[assembly: AssemblyFileVersion("2.6.0.0")]

SearchCondition.cs

@@ -324,7 +324,7 @@ public class SearchCondition {
 		/// SearchCondition instance with</param>
 		/// <returns>A new SearchCondition instance which can be further chained
 		/// with other search conditions.</returns>
-		public SearchCondition And(params SearchCondition[] other) {
+		public SearchCondition And(SearchCondition other) {
 			return Join(string.Empty, this, other);
 		}
 
@@ -337,7 +337,7 @@ public class SearchCondition {
 		/// message for it to be included in the search result set</param>
 		/// <returns>A new SearchCondition instance which can be further chained
 		/// with other search conditions.</returns>
-		public SearchCondition Not(params SearchCondition[] other) {
+		public SearchCondition Not(SearchCondition other) {
 			return Join("NOT", this, other);
 		}
 
@@ -350,10 +350,14 @@ public class SearchCondition {
 		/// SearchCondition instance with</param>
 		/// <returns>A new SearchCondition instance which can be further chained
 		/// with other search conditions.</returns>
-		public SearchCondition Or(params SearchCondition[] other) {
+		public SearchCondition Or(SearchCondition other) {
 			return Join("OR", this, other);
 		}
 
+		/// <summary>
+		/// The search keys which can be used with the IMAP SEARCH command, as
+		/// are defined in section 6.4.4 of RFC 3501.
+		/// </summary>
 		private enum Fields {
 			BCC, Before, Body, Cc, From, Header, Keyword,
 			Larger, On, SentBefore, SentOn, SentSince, Since, Smaller, Subject,
@@ -367,16 +371,23 @@ private enum Fields {
 		private string Operator { get; set; }
 		private bool Quote = true;
 
+		/// <summary>
+		/// Joins two SearchCondition objects into a new one using the specified
+		/// logical operator.
+		/// </summary>
+		/// <param name="condition">The logical operator to use for joining the
+		/// search conditions. Possible values are "OR", "NOT" and the empty
+		/// string "" which denotes a logical AND.</param>
+		/// <param name="left">The first SearchCondition object</param>
+		/// <param name="right">The second SearchCondition object</param>
+		/// <returns>A new SearchCondition object representing the two
+		/// search conditions joined by the specified logical operator.</returns>
 		private static SearchCondition Join(string condition, SearchCondition left,
-			params SearchCondition[] right) {
-			condition = condition.ToUpper();
-			if (left.Operator != condition)
-				left = new SearchCondition {
-					Operator = condition,
-					Conditions = new List<SearchCondition> { left }
-				};
-			left.Conditions.AddRange(right);
-			return left;
+			SearchCondition right) {
+			return new SearchCondition {
+				Operator = condition.ToUpper(),
+				Conditions = new List<SearchCondition> { left, right }
+			};
 		}
 
 		/// <summary>

Util.cs

@@ -127,40 +127,60 @@ internal static void Raise<T>(this EventHandler<T> @event, object sender, T args
 		/// <param name="value">The Q-encoded string to decode</param>
 		/// <param name="encoding">The encoding to use for encoding the
 		/// returned string</param>
+		/// <exception cref="FormatException">Thrown if the string is
+		/// not a valid Q-encoded string.</exception>
 		/// <returns>A Q-decoded string</returns>
 		internal static string QDecode(string value, Encoding encoding) {
-			MatchCollection matches = Regex.Matches(value, @"=[0-9A-Z]{2}",
-				RegexOptions.Multiline);
-			foreach (Match match in matches) {
-				char hexChar = (char)Convert.ToInt32(
-					match.Groups[0].Value.Substring(1), 16);
-				value = value.Replace(match.Groups[0].Value, hexChar.ToString());
+			try {
+				using (MemoryStream m = new MemoryStream()) {
+					for (int i = 0; i < value.Length; i++) {
+						if (value[i] == '=') {
+							string hex = value.Substring(i + 1, 2);
+							m.WriteByte(Convert.ToByte(hex, 16));
+							i = i + 2;
+						} else if (value[i] == '_') {
+							m.WriteByte(Convert.ToByte(' '));
+						} else {
+							m.WriteByte(Convert.ToByte(value[i]));
+						}
+					}
+					return encoding.GetString(m.ToArray());
+				}
+			} catch {
+				throw new FormatException("value is not a valid Q-encoded " +
+					"string");
 			}
-			value = value.Replace("=\r\n", "").Replace("_", " ");
-			return encoding.GetString(
-				Encoding.Default.GetBytes(value));
 		}
 
 		/// <summary>
-		/// Takes a quoted-printable-encoded string and decodes it using
+		/// Takes a quoted-printable encoded string and decodes it using
 		/// the specified encoding.
 		/// </summary>
 		/// <param name="value">The quoted-printable-encoded string to
 		/// decode</param>
 		/// <param name="encoding">The encoding to use for encoding the
 		/// returned string</param>
-		/// <returns>A quoted-printable-decoded string</returns>
+		/// <exception cref="FormatException">Thrown if the string is
+		/// not a valid quoted-printable encoded string.</exception>
+		/// <returns>A quoted-printable decoded string</returns>
 		internal static string QPDecode(string value, Encoding encoding) {
-			MatchCollection matches = Regex.Matches(value, @"=[0-9A-Z]{2}",
-				RegexOptions.Multiline);
-			foreach (Match match in matches) {
-				char hexChar = (char)Convert.ToInt32(
-					match.Groups[0].Value.Substring(1), 16);
-				value = value.Replace(match.Groups[0].Value, hexChar.ToString());
+			try {
+				using (MemoryStream m = new MemoryStream()) {
+					for (int i = 0; i < value.Length; i++) {
+						if (value[i] == '=') {
+							string hex = value.Substring(i + 1, 2);
+							m.WriteByte(Convert.ToByte(hex, 16));
+							i = i + 2;
+						} else {
+							m.WriteByte(Convert.ToByte(value[i]));
+						}
+					}
+					return encoding.GetString(m.ToArray());
+				}
+			} catch {
+				throw new FormatException("value is not a valid quoted-printable " +
+					"encoded string");
 			}
-			value = value.Replace("=\r\n", "");
-			return encoding.GetString(
-				Encoding.Default.GetBytes(value));
 		}
 
 		/// <summary>