/// <summary>
/// Writes the header of the file with the writer.
/// </summary>
/// <param name="writer"> The writer. </param>
/// <param name="entry"> The entry. </param>
/// <param name="isCentralFileHeader"> Determines whether header is central file header or not (local). </param>
private void WriteFileHeader(IByteArrayWriter writer, ZipWriteOnlyStorerEntry entry, bool isCentralFileHeader)
{
if (isCentralFileHeader)
{
writer.WriteBytes(centralDirectoryFileHeaderSignatureBytes); // 4 bytes, central directory file header signature
writer.WriteBytes(23, 0xB); // 2 bytes, version made by
}
else
{
writer.WriteBytes(localFileHeaderSignatureBytes); // 4 bytes, local file header signature
}
writer.WriteBytes(versionToExtractBytes); // 2 bytes, version needed to extract (minimum)
writer.WriteBytes(gpbg8Bytes); // 2 bytes, general purpose bit flag
writer.WriteBytes(entry.CompressionMethodAsBytes); // 2 bytes, compression method
writer.WriteBytes(entry.ModifyTimeAsBytes); // 2+2 bytes, file last modification time and date
writer.WriteBytes(entry.CRC32AsBytes); // 4 bytes, CRC-32
writer.WriteBytes(entry.CompressedSizeAsBytes); // 4 bytes, compressed size
writer.WriteBytes(entry.SizeAsBytes); // 4 bytes, uncompressed size
writer.WriteBytes(entry.PathLengthAsBytes); // 2 bytes, file name length
if (this.isZip64)
{
writer.WriteBytes(thirtyTwo2Bytes); // 2 bytes, extra field length = 32
}
else
{
writer.WriteBytes(zero2Bytes); // 2 bytes, extra field length = 32
}
if (isCentralFileHeader)
{
writer.WriteBytes(entry.CommentLengthAsBytes); // 2 bytes, file comment length
writer.WriteBytes(zero4Bytes); // 2+2=4 bytes, disk number where file starts (disk=0), internal file attributes
writer.WriteBytes(externalAttributesBytes); // 4 bytes, External file attributes
writer.WriteBytes(entry.HeaderOffsetAsBytes); // 4 bytes, relative offset of header
}
writer.WriteBytes(entry.PathAsBytes); // variable size, file name
if (this.isZip64)
{
writer.WriteBytes(zip64ExtraBlockTagSignatureBytes); // 2 bytes, tag for the extra block (ZIP64 Extended Information Extra Field)
writer.WriteBytes(thirtyTwo2Bytes); // 2 bytes, size of the extra block
writer.WriteBytes(zero4Bytes);
writer.WriteBytes(entry.SizeZip64AsBytes); // 8 bytes, uncompressed size
writer.WriteBytes(zero4Bytes);
writer.WriteBytes(entry.CompressedSizeZip64AsBytes); // 8 bytes, compressed size
writer.WriteBytes(zero4Bytes);
writer.WriteBytes(entry.HeaderOffsetZip64AsBytes); // 8 bytes, compressed size
writer.WriteBytes(zero4Bytes); // 4 bytes, disk number where file starts (disk=0)
}
if (isCentralFileHeader)
{
writer.WriteBytes(entry.CommentAsBytes); // variable size, file comment
}
}
/// <inheritdoc/>
public IDataStorerEntry Add(string path, params byte[] data)
{
Validation.NotNull("Path", path);
Validation.NotNull("Data", data);
string normalizedPath = path.Replace('\\', '/');
int pos = normalizedPath.IndexOf(':');
if (pos >= 0)
{
normalizedPath = normalizedPath.Remove(0, pos + 1);
}
normalizedPath = normalizedPath.Trim('/');
int uncompressedLength = data.Length;
int compressedLength;
byte[] compressedData;
CompressionMethod compressionMethod;
if (this.enableCompression)
{
Deflater deflater = new Deflater(Deflater.DEFLATED);
deflater.SetInput(data, 0, uncompressedLength);
deflater.Finish();
compressedData = new byte[uncompressedLength];
compressedLength = deflater.Deflate(compressedData, 0, uncompressedLength);
if (deflater.IsFinished && compressedLength <= uncompressedLength)
{
// Use deflate
compressionMethod = CompressionMethod.Deflate;
}
else
{
// Force to store
compressedData = data;
compressedLength = uncompressedLength;
compressionMethod = CompressionMethod.Store;
}
}
else
{
// Only store
compressedData = data;
compressedLength = uncompressedLength;
compressionMethod = CompressionMethod.Store;
}
uint uncompressedSize = (uint)uncompressedLength;
uint compressedSize = (uint)compressedLength;
uint crc32 = CRC32.Calculate(data);
uint headerOffset = (uint)this.zipFileWriter.Position;
ZipWriteOnlyStorerEntry fileEntry = new ZipWriteOnlyStorerEntry(
normalizedPath,
uncompressedSize,
compressionMethod,
compressedSize,
headerOffset,
crc32,
DateTime.Now,
comment ?? ""
);
this.WriteFileHeader(this.zipFileWriter, fileEntry, false);
this.zipFileWriter.WriteBytes(compressedData, 0, compressedLength);
this.entries.AddLast(fileEntry);
return(fileEntry);
}
