/// <summary>
/// Create a new LocalFileHeader
/// </summary>
/// <param name="fileName"></param>
/// <param name="encoding"></param>
/// <param name="compressionMethod"></param>
/// <param name="deflateOption"></param>
/// <param name="streaming">true if in streaming mode</param>
/// <returns></returns>
internal static ZipIOLocalFileHeader CreateNew(string fileName, Encoding encoding,
CompressionMethodEnum compressionMethod, DeflateOptionEnum deflateOption, bool streaming)
{
//this should be ensured by the higher levels
Debug.Assert(Enum.IsDefined(typeof(CompressionMethodEnum), compressionMethod));
Debug.Assert(Enum.IsDefined(typeof(DeflateOptionEnum), deflateOption));
byte[] asciiName = encoding.GetBytes(fileName);
if (asciiName.Length > ZipIOBlockManager.MaxFileNameSize)
{
throw new ArgumentOutOfRangeException("fileName");
}
ZipIOLocalFileHeader header = new ZipIOLocalFileHeader();
header._signature = ZipIOLocalFileHeader._signatureConstant;
header._compressionMethod = (ushort)compressionMethod;
if (streaming)
{
header._versionNeededToExtract = (UInt16)ZipIOVersionNeededToExtract.Zip64FileFormat;
}
else
{
header._versionNeededToExtract = (UInt16)ZipIOBlockManager.CalcVersionNeededToExtractFromCompression(
compressionMethod);
}
if (compressionMethod != CompressionMethodEnum.Stored)
{
Debug.Assert(deflateOption != DeflateOptionEnum.None); //this should be ensured by the higher levels
header.DeflateOption = deflateOption;
}
if (streaming)
{
// set bit 3
header.StreamingCreationFlag = true;
}
header._lastModFileDateTime = ZipIOBlockManager.ToMsDosDateTime(DateTime.Now);
header._fileNameLength = (UInt16)asciiName.Length;
header._fileName = asciiName;
header._extraField = ZipIOExtraField.CreateNew(!streaming /* creating padding if it is not in streaming creation mode */);
header._extraFieldLength = header._extraField.Size;
//populate frequently used field with user friendly data representations
header._stringFileName = fileName;
return(header);
}
// this function is sets the sizes into the either 64 or 32 bit structures based on values of the fields
// It used in 2 places by the MoveReference and by the UpdateFromLocalFileBlock
private void UpdateZip64Structures
(long compressedSize, long uncompressedSize, long offset)
{
Debug.Assert((compressedSize >= 0) && (uncompressedSize >= 0) && (offset >= 0));
// according to the appnote central directory extra field might be a mix of any values based on escaping
// we will fully (without disk number) use it every time we are building a ZIP 64 arhichive
// we also trying to stay on the safe side and treeat the boundary case of 32 escape values
// as a zip 64 scenrio
if ((compressedSize >= UInt32.MaxValue) ||
(uncompressedSize >= UInt32.MaxValue) ||
(offset >= UInt32.MaxValue))
{
// Zip 64 case
_extraField.CompressedSize = compressedSize;
_extraField.UncompressedSize = uncompressedSize;
_extraField.OffsetOfLocalHeader = offset;
//set proper escape values
_compressedSize = UInt32.MaxValue;
_uncompressedSize = UInt32.MaxValue;
_relativeOffsetOfLocalHeader = UInt32.MaxValue;
// update version needed to extract to 4.5
_versionNeededToExtract = (UInt16)ZipIOVersionNeededToExtract.Zip64FileFormat;
}
else
{
// 32 bit case
_compressedSize = checked ((UInt32)compressedSize);
_uncompressedSize = checked ((UInt32)uncompressedSize);
_relativeOffsetOfLocalHeader = checked ((UInt32)offset);
// reset the extra ZIP 64 field to empty
_extraField.Zip64ExtraFieldUsage = ZipIOZip64ExtraFieldUsage.None;
// version needed to extract needs to be recalculated from scratch based on compression
_versionNeededToExtract = (UInt16)ZipIOBlockManager.CalcVersionNeededToExtractFromCompression
((CompressionMethodEnum)_compressionMethod);
}
}
internal void UpdateZip64Structures(long compressedSize,
long uncompressedSize,
long offset)
{
// according to the appnote local file header ZIP 64 extra field if used must contain both
// compressed and uncompressed size
// we also trying to stay on the safe side and treeat the boundary case of 32 escape values
// as a zip 64 scenario
// we will also make this ZIP64 file if it is small but positioned beyond Uint32.MaxValue offset
if ((compressedSize >= UInt32.MaxValue) ||
(uncompressedSize >= UInt32.MaxValue) ||
(offset >= UInt32.MaxValue))
{
// Zip 64 case
_extraField.CompressedSize = compressedSize;
_extraField.UncompressedSize = uncompressedSize;
//set proper escape values
_compressedSize = UInt32.MaxValue;
_uncompressedSize = UInt32.MaxValue;
// update version needed to extract to 4.5
_versionNeededToExtract = (UInt16)ZipIOVersionNeededToExtract.Zip64FileFormat;
}
else
{
// 32 bit case
_compressedSize = (UInt32)compressedSize; // checked{} isn't required because of the checks above
_uncompressedSize = (UInt32)uncompressedSize;
// reset the extra ZIP 64 field to empty
_extraField.Zip64ExtraFieldUsage = ZipIOZip64ExtraFieldUsage.None;
// version needed to extract needs to be recalculated from scratch based on compression
_versionNeededToExtract =
(UInt16)ZipIOBlockManager.CalcVersionNeededToExtractFromCompression(CompressionMethod);
}
}
