SabreTools/SabreTools.Serialization
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Add PKZIP archive extra data record parsing

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This commit is contained in:
Matt Nadareski
2024-04-27 23:01:50 -04:00
parent f4de2e27d7
commit c8c45446bc
1 changed files with 82 additions and 1 deletions
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83
SabreTools.Serialization/Deserializers/PKZIP.cs
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@@ -138,6 +138,26 @@ namespace SabreTools.Serialization.Deserializers
#endregion
#region Archive Extra Data Record
// Find the archive extra data record
long aedrOffset = SearchForArchiveExtraDataRecord(data, cdrOffset);
if (aedrOffset >= 0 && aedrOffset < data.Length)
{
// Seek to the archive extra data record
data.Seek(aedrOffset, SeekOrigin.Begin);
// Read the archive extra data record
var aedr = ParseArchiveExtraDataRecord(data);
if (aedr == null)
return null;
// Assign the archive extra data record
archive.ArchiveExtraDataRecord = aedr;
}
#endregion
#region Local File
// Setup all of the collections
@@ -260,7 +280,6 @@ namespace SabreTools.Serialization.Deserializers
#endregion
// TODO: Handle archive decryption header
// TODO: Handle archive extra data record
return archive;
}
@@ -467,6 +486,68 @@ namespace SabreTools.Serialization.Deserializers
return header;
}
/// <summary>
/// Search for the archive extra data record
/// </summary>
/// <param name="data">Stream to parse</param>
/// <param name="centralDirectoryoffset">Offset to the first central directory record</param>
/// <returns>Position of the archive extra data record, -1 on error</returns>
public static long SearchForArchiveExtraDataRecord(Stream data, long centralDirectoryoffset)
{
// Cache the current offset
long current = data.Position;
// Seek to the minimum size of the record from the central directory
data.Seek(centralDirectoryoffset - 8, SeekOrigin.Begin);
// Attempt to find the end of central directory signature
while (data.Position > 0)
{
// Read the potential signature
uint possibleSignature = data.ReadUInt32();
if (possibleSignature == ArchiveExtraDataRecordSignature)
{
long signaturePosition = data.Position - 4;
data.Seek(current, SeekOrigin.Begin);
return signaturePosition;
}
// Seek backward 5 bytes, if possible
data.Seek(-5, SeekOrigin.Current);
}
// No signature was found
data.Seek(current, SeekOrigin.Begin);
return -1;
}
/// <summary>
/// Parse a Stream into an archive extra data record
/// </summary>
/// <param name="data">Stream to parse</param>
/// <returns>Filled archive extra data record on success, null on error</returns>
public static ArchiveExtraDataRecord? ParseArchiveExtraDataRecord(Stream data)
{
// TODO: Use marshalling here instead of building
var record = new ArchiveExtraDataRecord();
record.Signature = data.ReadUInt32();
if (record.Signature != ArchiveExtraDataRecordSignature)
return null;
record.ExtraFieldLength = data.ReadUInt32();
if (record.ExtraFieldLength > 0)
{
byte[] extraBytes = data.ReadBytes((int)record.ExtraFieldLength);
if (extraBytes.Length != record.ExtraFieldLength)
return null;
record.ExtraFieldData = extraBytes;
}
return record;
}
/// <summary>
/// Parse a Stream into a local file header
/// </summary>