RarStream Position fix, it was returning the file size. 7Zip CrcCheckStream always failed. Added a Solid Rar entry CRC test.

src/SharpCompress/Compressors/LZMA/Utilites/CrcCheckStream.cs

@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.Diagnostics;
 using System.IO;
 
@@ -21,16 +21,17 @@ namespace SharpCompress.Compressors.LZMA.Utilites
 
         protected override void Dispose(bool disposing)
         {
-            if (_mCurrentCrc != _mExpectedCrc)
-            {
-                throw new InvalidOperationException();
-            }
+            //Nanook - is not equal here - _mCurrentCrc is yet to be negated
+            //if (_mCurrentCrc != _mExpectedCrc)
+            //{
+            //    throw new InvalidOperationException();
+            //}
             try
             {
                 if (disposing && !_mClosed)
                 {
                     _mClosed = true;
-                    _mCurrentCrc = Crc.Finish(_mCurrentCrc);
+                    _mCurrentCrc = Crc.Finish(_mCurrentCrc); //now becomes equal
 #if DEBUG
                     if (_mCurrentCrc == _mExpectedCrc)
                     {
@@ -40,6 +41,7 @@ namespace SharpCompress.Compressors.LZMA.Utilites
                     {
                         Debugger.Break();
                         Debug.WriteLine("bad CRC");
+                        throw new InvalidOperationException(); //moved exception to here
                     }
 
                     double lengthInv = 1.0 / _mLength;
@@ -102,4 +104,4 @@ namespace SharpCompress.Compressors.LZMA.Utilites
             _mCurrentCrc = Crc.Update(_mCurrentCrc, buffer, offset, count);
         }
     }
-}
+}

src/SharpCompress/Compressors/Rar/RarStream.cs

@@ -1,4 +1,4 @@
-#nullable disable
+#nullable disable
 
 using System;
 using System.IO;
@@ -23,6 +23,7 @@ namespace SharpCompress.Compressors.Rar
         private int outCount;
         private int outTotal;
         private bool isDisposed;
+        private long _position;
 
         public RarStream(IRarUnpack unpack, FileHeader fileHeader, Stream readStream)
         {
@@ -32,6 +33,7 @@ namespace SharpCompress.Compressors.Rar
             fetch = true;
             unpack.DoUnpack(fileHeader, readStream, this);
             fetch = false;
+            _position = 0;
         }
 
         protected override void Dispose(bool disposing)
@@ -56,7 +58,8 @@ namespace SharpCompress.Compressors.Rar
 
         public override long Length => fileHeader.UncompressedSize;
 
-        public override long Position { get => fileHeader.UncompressedSize - unpack.DestSize; set => throw new NotSupportedException(); }
+        //commented out code always returned the length of the file
+        public override long Position { get => _position; /* fileHeader.UncompressedSize - unpack.DestSize;*/ set => throw new NotSupportedException(); }
 
         public override int Read(byte[] buffer, int offset, int count)
         {
@@ -80,6 +83,7 @@ namespace SharpCompress.Compressors.Rar
                 unpack.DoUnpack();
                 fetch = false;
             }
+            _position += (long)outTotal;
             return outTotal;
         }
 
@@ -129,4 +133,4 @@ namespace SharpCompress.Compressors.Rar
             }
         }
     }
-}
+}

tests/SharpCompress.Test/Rar/RarArchiveTests.cs

@@ -1,8 +1,9 @@
-using System.IO;
+using System.IO;
 using System.Linq;
 using SharpCompress.Archives;
 using SharpCompress.Archives.Rar;
 using SharpCompress.Common;
+using SharpCompress.Compressors.LZMA.Utilites;
 using SharpCompress.Readers;
 using Xunit;
 
@@ -203,6 +204,43 @@ namespace SharpCompress.Test.Rar
             VerifyFiles();
         }
 
+
+        [Fact]
+        public void Rar_IsSolidEntryStreamCheck()
+        {
+            DoRar_IsSolidEntryStreamCheck("Rar.solid.rar");
+        }
+
+        //Extract the 2nd file in a solid archive to check that the first file is skipped properly
+        private void DoRar_IsSolidEntryStreamCheck(string filename)
+        {
+            using (var stream = File.OpenRead(Path.Combine(TEST_ARCHIVES_PATH, filename)))
+            {
+                using (var archive = RarArchive.Open(stream))
+                {
+                    Assert.True(archive.IsSolid);
+                    IArchiveEntry[] entries = archive.Entries.Where(a => !a.IsDirectory).ToArray();
+                    Assert.NotInRange(entries.Length, 0, 1);
+                    Assert.False(entries[0].IsSolid); //first item in a solid archive is not marked solid and is seekable
+                    IArchiveEntry testEntry = entries[1];
+                    Assert.True(testEntry.IsSolid); //the target. The non seekable entry
+
+                    //process all entries in solid archive until the one we want to test
+                    foreach (var entry in archive.Entries.Where(entry => !entry.IsDirectory))
+                    {
+                        using (CrcCheckStream crcStream = new CrcCheckStream((uint)entry.Crc)) //use the 7zip CRC stream for convenience (required a bug fix)
+                        {
+                            using (Stream eStream = entry.OpenEntryStream()) //bug fix in RarStream to report the correct Position
+                                eStream.CopyTo(crcStream);
+                            if (entry == testEntry)
+                                break;
+                        } //throws if not valid
+                    }
+                }
+            }
+        }
+
+
         [Fact]
         public void Rar_Solid_ArchiveStreamRead()
         {