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fix case where a ZIP archive appears in the middle of random data; allow us to load ZIP archives embedded in other kinds of files

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Michael Becker 2019-12-28 21:10:12 -05:00
parent 499948e7e0
commit f55d9bdcac
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GPG Key ID: 506F54899E2BFED7
1 changed files with 22 additions and 3 deletions
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25
CSharp/Plugins/UniversalEditor.Plugins.FileSystem/DataFormats/FileSystem/ZIP/ZIPDataFormat.cs
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@ -23,11 +23,14 @@ namespace UniversalEditor.DataFormats.FileSystem.ZIP
private ZIPSettings mvarSettings = new ZIPSettings();
private static readonly byte[] SIG_CENTRAL_DIRECTORY_ENTRY = new byte[] { 0x50, 0x4B, 0x01, 0x02 };
private static readonly byte[] SIG_DIRECTORY_ENTRY = new byte[] { 0x50, 0x4B, 0x03, 0x04 };
private static readonly byte[] SIG_END_OF_CENTRAL_DIRECTORY = new byte[] { 0x50, 0x4B, 0x05, 0x06 };
private string mvarComment = String.Empty;
public string Comment { get { return mvarComment; } set { mvarComment = value; } }
private long _offsetToBeginningOfZIPFile = 0;
protected override DataFormatReference MakeReferenceInternal()
{
DataFormatReference dfr = base.MakeReferenceInternal();
@ -44,6 +47,21 @@ namespace UniversalEditor.DataFormats.FileSystem.ZIP
IO.Reader br = base.Accessor.Reader;
br.Accessor.SavePosition();
while (!br.EndOfStream)
{
byte[] siggy = br.ReadBytes(4);
if (siggy.Match(SIG_DIRECTORY_ENTRY))
{
_offsetToBeginningOfZIPFile = br.Accessor.Position - 4;
break;
}
else
{
br.Seek(-3, SeekOrigin.Current);
}
}
br.Accessor.LoadPosition();
long eocdOffset = zip_FindEndOfCentralDirectory(br);
if (eocdOffset != -1)
@ -52,7 +70,7 @@ namespace UniversalEditor.DataFormats.FileSystem.ZIP
Internal.ZIPCentralDirectoryFooter footer = ReadZIPCentralDirectoryFooter(br);
if (footer.centralDirectoryOffset > 0 && footer.centralDirectoryOffset < br.Accessor.Length)
{
br.Seek(footer.centralDirectoryOffset, SeekOrigin.Begin);
br.Seek(_offsetToBeginningOfZIPFile + footer.centralDirectoryOffset, SeekOrigin.Begin);
long pos = br.Accessor.Position;
while (br.Accessor.Position < footer.centralDirectoryLength + pos)
@ -82,7 +100,7 @@ namespace UniversalEditor.DataFormats.FileSystem.ZIP
string fileName = br.ReadFixedLengthString(fileNameLength);
long local_pos = br.Accessor.Position;
while (br.Accessor.Position < (local_pos + extraFieldLength))
while (br.Accessor.Position < (local_pos + extraFieldLength) && br.Accessor.Position < br.Accessor.Length)
{
short chunkIDCode = br.ReadInt16();
short chunkLength = br.ReadInt16();
@ -196,6 +214,7 @@ namespace UniversalEditor.DataFormats.FileSystem.ZIP
uint decompressedLength = (uint)file.Properties["decompressedLength"];
uint compressedLength = (uint)file.Properties["compressedLength"];
uint offset = (uint)file.Properties["offset"];
offset += (uint)_offsetToBeginningOfZIPFile;
Reader br = Accessor.Reader;
long curpos = Accessor.Position;
@ -696,7 +715,7 @@ namespace UniversalEditor.DataFormats.FileSystem.ZIP
private long zip_FindEndOfCentralDirectory(IO.Reader reader)
{
reader.Seek(-4, SeekOrigin.End);
while (true)
while (reader.Accessor.Position > 0)
{
byte[] test = reader.ReadBytes(4);
if (test.Match(SIG_END_OF_CENTRAL_DIRECTORY))