Container reader: keep scanning past gaps over 4096 bytes

src/NwcIO/Internal/Container/NwcContainerReader.cs

@@ -11,9 +11,6 @@ public static class NwcContainerReader
 {
     private const string SectionMarker = "#LcUStream";
 
-    /// <summary>Largest run of unrecognized non-zlib bytes tolerated while re-syncing between streams.</summary>
-    private const int MaxResyncGap = 4096;
-
     public static NwcContainer Read(byte[] data)
     {
         if (data.Length < 16 || !StartsWithAscii(data, 0, SectionMarker))
@@ -57,9 +54,8 @@ public static NwcContainer Read(byte[] data)
             // Non-zlib bytes: framing blocks (hash + size words), section padding, tail.
             // Scan forward to the next zlib signature or section header.
             int scan = pos + 1;
-            int limit = Math.Min(data.Length, pos + MaxResyncGap);
             int gapEnd = -1;
-            while (scan < limit)
+            while (scan < data.Length)
             {
                 if (IsZlibSignature(data, scan) || StartsWithAscii(data, scan, SectionMarker))
                 {

tests/NwcIO.Tests/ContainerReaderTests.cs

@@ -35,6 +35,43 @@ public void Read_SyntheticBackToBackStreams_InflatesAndPreservesLengths()
         Assert.Equal(comp2.Length, container.Streams[1].CompressedLength);
     }
 
+    [Theory]
+    [InlineData(0)]
+    [InlineData(7)]
+    public void Read_LargeGaps_PreservesLaterStreamsSectionsAndGapAccounting(int trailingGap)
+    {
+        using var ms = new MemoryStream();
+        var headerBytes = System.Text.Encoding.ASCII.GetBytes("#LcUStream-V1.1 binary double release C lichunk-008\n");
+        var payload1 = new byte[100];
+        var payload2 = new byte[200];
+        var payload3 = new byte[50];
+        var gap = new byte[5000];
+
+        ms.Write(headerBytes);
+        ms.Write(CompressZlib(payload1));
+        ms.Write(gap);
+        ms.Write(CompressZlib(payload2));
+        ms.Write(gap);
+        ms.Write(headerBytes);
+        ms.Write(CompressZlib(payload3));
+        ms.Write(new byte[trailingGap]);
+
+        var container = NwcContainerReader.Read(ms.ToArray());
+
+        Assert.Equal(2, container.Sections.Count);
+        Assert.Equal(3, container.Streams.Count);
+        Assert.Equal(payload1, container.Streams[0].Data);
+        Assert.Equal(payload2, container.Streams[1].Data);
+        Assert.Equal(payload3, container.Streams[2].Data);
+        Assert.Equal(0, container.Streams[0].SectionIndex);
+        Assert.Equal(0, container.Streams[1].SectionIndex);
+        Assert.Equal(1, container.Streams[2].SectionIndex);
+        Assert.Equal(0, container.Streams[0].GapBefore);
+        Assert.Equal(gap.Length, container.Streams[1].GapBefore);
+        Assert.Equal(0, container.Streams[2].GapBefore);
+        Assert.Equal(trailingGap, container.TrailingGap);
+    }
+
     [Fact]
     public void Read_InvalidHeader_ThrowsInvalidDataException()
     {