// returns false if fails, will get called on every entry before closing in update mode
// can throw InvalidDataException
internal bool LoadLocalHeaderExtraFieldAndCompressedBytesIfNeeded()
{
string message;
// we should have made this exact call in _archive.Init through ThrowIfOpenable
Debug.Assert(IsOpenable(false, true, out message));
// load local header's extra fields. it will be null if we couldn't read for some reason
if (_originallyInArchive)
{
_archive.ArchiveStream.Seek(_offsetOfLocalHeader, SeekOrigin.Begin);
_lhUnknownExtraFields = ZipLocalFileHeader.GetExtraFields(_archive.ArchiveReader);
}
if (!_everOpenedForWrite && _originallyInArchive)
{
// we know that it is openable at this point
_compressedBytes = new byte[(_compressedSize / MaxSingleBufferSize) + 1][];
for (int i = 0; i < _compressedBytes.Length - 1; i++)
{
_compressedBytes[i] = new byte[MaxSingleBufferSize];
}
_compressedBytes[_compressedBytes.Length - 1] = new byte[_compressedSize % MaxSingleBufferSize];
_archive.ArchiveStream.Seek(OffsetOfCompressedData, SeekOrigin.Begin);
for (int i = 0; i < _compressedBytes.Length - 1; i++)
{
ZipHelper.ReadBytes(_archive.ArchiveStream, _compressedBytes[i], MaxSingleBufferSize);
}
ZipHelper.ReadBytes(_archive.ArchiveStream, _compressedBytes[_compressedBytes.Length - 1], ( int )(_compressedSize % MaxSingleBufferSize));
}
return(true);
}
private bool IsOpenable(bool needToUncompress, bool needToLoadIntoMemory, out string message)
{
message = null;
if (_originallyInArchive)
{
if (needToUncompress)
{
if (CompressionMethod != CompressionMethodValues.Stored &&
CompressionMethod != CompressionMethodValues.Deflate &&
CompressionMethod != CompressionMethodValues.Deflate64)
{
switch (CompressionMethod)
{
case CompressionMethodValues.BZip2:
case CompressionMethodValues.LZMA:
message = $"Unsupport compression method:{CompressionMethod.ToString()}";
break;
default:
message = $"Unsupport compression method";
break;
}
return(false);
}
}
if (_diskNumberStart != _archive.NumberOfThisDisk)
{
message = "split spanned";
return(false);
}
if (_offsetOfLocalHeader > _archive.ArchiveStream.Length)
{
message = "local file header corrupt";
return(false);
}
_archive.ArchiveStream.Seek(_offsetOfLocalHeader, SeekOrigin.Begin);
if (!ZipLocalFileHeader.TrySkipBlock(_archive.ArchiveReader))
{
message = "local file header corrupt";
return(false);
}
// when this property gets called, some duplicated work
if (OffsetOfCompressedData + _compressedSize > _archive.ArchiveStream.Length)
{
message = "local file header corrupt";
return(false);
}
// This limitation originally existed because a) it is unreasonable to load > 4GB into memory
// but also because the stream reading functions make it hard. This has been updated to handle
// this scenario in a 64-bit process using multiple buffers, delivered first as an OOB for
// compatibility.
if (needToLoadIntoMemory)
{
if (_compressedSize > int.MaxValue)
{
if (!s_allowLargeReadOnlyZipArchiveEntriesInUpdateMode)
{
message = "entry too large";
return(false);
}
}
}
}
return(true);
}