From d2cfc1844cdca9e168a50ebc80920362e21f4283 Mon Sep 17 00:00:00 2001
From: Morilli <35152647+Morilli@users.noreply.github.com>
Date: Tue, 28 Jan 2025 01:49:49 +0100
Subject: [PATCH 1/4] add failing test

---
 tests/SharpCompress.Test/Zip/ZipArchiveTests.cs | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/tests/SharpCompress.Test/Zip/ZipArchiveTests.cs b/tests/SharpCompress.Test/Zip/ZipArchiveTests.cs
index 4fb6d89a..cf376ec1 100644
--- a/tests/SharpCompress.Test/Zip/ZipArchiveTests.cs
+++ b/tests/SharpCompress.Test/Zip/ZipArchiveTests.cs
@@ -808,4 +808,14 @@ public void Zip_Forced_Ignores_UnicodePathExtra()
             Assert.Equal("きょきゅんきゃんきゅ_wav.frq", reader.Entry.Key);
         }
     }
+
+    [Fact]
+    public void TestDataDescriptorRead()
+    {
+        using var archive = ArchiveFactory.Open(Path.Combine(TEST_ARCHIVES_PATH, "Zip.none.datadescriptors.zip"));
+        var firstEntry = archive.Entries.First();
+        Assert.Equal(199, firstEntry.Size);
+        using var _ = firstEntry.OpenEntryStream();
+        Assert.Equal(199, firstEntry.Size);
+    }
 }

From c14d18b9dfb961d5cd78bc42e89486c5a76f538f Mon Sep 17 00:00:00 2001
From: Morilli <35152647+Morilli@users.noreply.github.com>
Date: Tue, 28 Jan 2025 01:56:14 +0100
Subject: [PATCH 2/4] set local header data from directory header when flag is
 set

As described in section 4.4.7-4.4.9 of the zip specification when this flag is set the correct values will be in the data descriptor record and in the directory header.
---
 src/SharpCompress/Common/Zip/SeekableZipHeaderFactory.cs | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/SharpCompress/Common/Zip/SeekableZipHeaderFactory.cs b/src/SharpCompress/Common/Zip/SeekableZipHeaderFactory.cs
index b99d0e2b..816b0b67 100644
--- a/src/SharpCompress/Common/Zip/SeekableZipHeaderFactory.cs
+++ b/src/SharpCompress/Common/Zip/SeekableZipHeaderFactory.cs
@@ -149,6 +149,12 @@ DirectoryEntryHeader directoryEntryHeader
         {
             throw new InvalidOperationException();
         }
+        if (FlagUtility.HasFlag(localEntryHeader.Flags, HeaderFlags.UsePostDataDescriptor))
+        {
+            localEntryHeader.Crc = directoryEntryHeader.Crc;
+            localEntryHeader.CompressedSize = directoryEntryHeader.CompressedSize;
+            localEntryHeader.UncompressedSize = directoryEntryHeader.UncompressedSize;
+        }
         return localEntryHeader;
     }
 }

From 91e672befb94ea8e529a836b44515917973b68bc Mon Sep 17 00:00:00 2001
From: Morilli <35152647+Morilli@users.noreply.github.com>
Date: Tue, 28 Jan 2025 02:06:47 +0100
Subject: [PATCH 3/4] remove old hack trying to fix a similar thing

Introduced in af264cdc58c9d076bf83477cbdbfe7a5dad282b7; the test included in that commit passes still.
---
 .../Common/Zip/SeekableZipFilePart.cs          | 18 +-----------------
 1 file changed, 1 insertion(+), 17 deletions(-)

diff --git a/src/SharpCompress/Common/Zip/SeekableZipFilePart.cs b/src/SharpCompress/Common/Zip/SeekableZipFilePart.cs
index e37008e5..54c4f527 100644
--- a/src/SharpCompress/Common/Zip/SeekableZipFilePart.cs
+++ b/src/SharpCompress/Common/Zip/SeekableZipFilePart.cs
@@ -1,6 +1,5 @@
 using System.IO;
 using SharpCompress.Common.Zip.Headers;
-using SharpCompress.IO;
 
 namespace SharpCompress.Common.Zip;
 
@@ -8,18 +7,13 @@ internal class SeekableZipFilePart : ZipFilePart
 {
     private bool _isLocalHeaderLoaded;
     private readonly SeekableZipHeaderFactory _headerFactory;
-    private readonly DirectoryEntryHeader _directoryEntryHeader;
 
     internal SeekableZipFilePart(
         SeekableZipHeaderFactory headerFactory,
         DirectoryEntryHeader header,
         Stream stream
     )
-        : base(header, stream)
-    {
-        _headerFactory = headerFactory;
-        _directoryEntryHeader = header;
-    }
+        : base(header, stream) => _headerFactory = headerFactory;
 
     internal override Stream GetCompressedStream()
     {
@@ -44,16 +38,6 @@ protected override Stream CreateBaseStream()
     {
         BaseStream.Position = Header.DataStartPosition.NotNull();
 
-        if (
-            (Header.CompressedSize == 0)
-            && FlagUtility.HasFlag(Header.Flags, HeaderFlags.UsePostDataDescriptor)
-            && _directoryEntryHeader.HasData
-            && (_directoryEntryHeader.CompressedSize != 0)
-        )
-        {
-            return new ReadOnlySubStream(BaseStream, _directoryEntryHeader.CompressedSize);
-        }
-
         return BaseStream;
     }
 }

From f9a974c1fef3bb34c5c08f51699f599b5edeef5c Mon Sep 17 00:00:00 2001
From: Morilli <35152647+Morilli@users.noreply.github.com>
Date: Tue, 28 Jan 2025 02:24:42 +0100
Subject: [PATCH 4/4] fix formatting

---
 tests/SharpCompress.Test/Zip/ZipArchiveTests.cs | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/tests/SharpCompress.Test/Zip/ZipArchiveTests.cs b/tests/SharpCompress.Test/Zip/ZipArchiveTests.cs
index cf376ec1..8419f58f 100644
--- a/tests/SharpCompress.Test/Zip/ZipArchiveTests.cs
+++ b/tests/SharpCompress.Test/Zip/ZipArchiveTests.cs
@@ -812,7 +812,9 @@ public void Zip_Forced_Ignores_UnicodePathExtra()
     [Fact]
     public void TestDataDescriptorRead()
     {
-        using var archive = ArchiveFactory.Open(Path.Combine(TEST_ARCHIVES_PATH, "Zip.none.datadescriptors.zip"));
+        using var archive = ArchiveFactory.Open(
+            Path.Combine(TEST_ARCHIVES_PATH, "Zip.none.datadescriptors.zip")
+        );
         var firstEntry = archive.Entries.First();
         Assert.Equal(199, firstEntry.Size);
         using var _ = firstEntry.OpenEntryStream();