Support long names in Tar archives ("prefix" header field as defined by ustar)

Author: bastianeicher

ICSharpCode.SharpZipLib/Tar/TarHeader.cs

@@ -147,6 +147,11 @@ public class TarHeader : ICloneable
 		/// </summary>
 		public const int DEVLEN = 8;
 
+		/// <summary>
+		/// The length of the name prefix field in a header buffer.
+		/// </summary>
+		public const int PREFIXLEN = 155;
+
 		//
 		// LF_ constants represent the "type" of an entry
 		//
@@ -597,21 +602,26 @@ public void ParseBuffer(byte[] header)
 			Magic = ParseName(header, offset, MAGICLEN).ToString();
 			offset += MAGICLEN;
 
-			Version = ParseName(header, offset, VERSIONLEN).ToString();
-			offset += VERSIONLEN;
+			if (Magic == "ustar")
+			{
+				Version = ParseName(header, offset, VERSIONLEN).ToString();
+				offset += VERSIONLEN;
 
-			UserName = ParseName(header, offset, UNAMELEN).ToString();
-			offset += UNAMELEN;
+				UserName = ParseName(header, offset, UNAMELEN).ToString();
+				offset += UNAMELEN;
 
-			GroupName = ParseName(header, offset, GNAMELEN).ToString();
-			offset += GNAMELEN;
+				GroupName = ParseName(header, offset, GNAMELEN).ToString();
+				offset += GNAMELEN;
 
-			DevMajor = (int)ParseOctal(header, offset, DEVLEN);
-			offset += DEVLEN;
+				DevMajor = (int) ParseOctal(header, offset, DEVLEN);
+				offset += DEVLEN;
 
-			DevMinor = (int)ParseOctal(header, offset, DEVLEN);
+				DevMinor = (int) ParseOctal(header, offset, DEVLEN);
+				offset += DEVLEN;
 
-			// Fields past this point not currently parsed or used...
+				string prefix = ParseName(header, offset, PREFIXLEN).ToString();
+				if (!string.IsNullOrEmpty(prefix)) Name = prefix + '/' + Name;
+			}
 
 			isChecksumValid = Checksum == TarHeader.MakeCheckSum(header);
 		}