ZipIOLocalFileHeader.cs source code in C# .NET

                        Code:
                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / wpf / src / Base / MS / Internal / IO / Zip / ZipIOLocalFileHeader.cs / 1305600 / ZipIOLocalFileHeader.cs
                        
                        
                            //------------------------------------------------------------------------------ 
//-------------   *** WARNING ***
//-------------    This file is part of a legally monitored development project.
//-------------    Do not check in changes to this project.  Do not raid bugs on this
//-------------    code in the main PS database.  Do not contact the owner of this 
//-------------    code directly.  Contact the legal team at �ZSLegal� for assistance.
//-------------   *** WARNING *** 
//----------------------------------------------------------------------------- 

//----------------------------------------------------------------------------- 
//
// 
//    Copyright (C) Microsoft Corporation.  All rights reserved.
//  
//
// Description: 
//  This is an internal class that enables interactions with Zip archives 
//  for OPC scenarios
// 
// History:
//  11/19/2004: IgorBel: Initial creation.
//
//----------------------------------------------------------------------------- 

using System; 
using System.IO; 
using System.Diagnostics;
using System.Text; 
using System.Collections;
using System.Runtime.Serialization;
using System.Windows;
using MS.Internal.WindowsBase; 

namespace MS.Internal.IO.Zip 
{ 
    internal class ZipIOLocalFileHeader
    { 
        /// 
        /// Create a new LocalFileHeader
        /// 
        ///  
        /// 
        ///  
        ///  
        /// true if in streaming mode
        ///  
        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; 
        }
 
        internal static ZipIOLocalFileHeader ParseRecord(BinaryReader reader, Encoding encoding) 
        {
            ZipIOLocalFileHeader header = new ZipIOLocalFileHeader(); 

            header._signature =  reader.ReadUInt32();
            header._versionNeededToExtract = reader.ReadUInt16();
            header._generalPurposeBitFlag = reader.ReadUInt16(); 
            header._compressionMethod = reader.ReadUInt16();
            header._lastModFileDateTime = reader.ReadUInt32(); 
            header._crc32 = reader.ReadUInt32(); 
            header._compressedSize = reader.ReadUInt32();
            header._uncompressedSize = reader.ReadUInt32(); 
            header._fileNameLength = reader.ReadUInt16();
            header._extraFieldLength = reader.ReadUInt16();

            header._fileName = reader.ReadBytes(header._fileNameLength); 

            // check for the ZIP 64 version and escaped values 
            ZipIOZip64ExtraFieldUsage zip64extraFieldUsage = ZipIOZip64ExtraFieldUsage.None; 
            if (header._versionNeededToExtract >= (ushort)ZipIOVersionNeededToExtract.Zip64FileFormat)
            { 
                if (header._compressedSize == UInt32.MaxValue)
                {
                    zip64extraFieldUsage |= ZipIOZip64ExtraFieldUsage.CompressedSize;
                } 
                if (header._uncompressedSize == UInt32.MaxValue)
                { 
                    zip64extraFieldUsage |= ZipIOZip64ExtraFieldUsage.UncompressedSize; 
                }
            } 

            // if the ZIP 64 record is missing from the Extra Field then the  zip64extraFieldUsage
            // value will be ignored and default ZipIOZip64ExtraFieldUsage.None value will be used/assumed
            header._extraField = ZipIOExtraField.ParseRecord(reader, 
                                             zip64extraFieldUsage,
                                            header._extraFieldLength); 
 
            //populate frequently used field with user friendly data representations
            header._stringFileName = ZipIOBlockManager.ValidateNormalizeFileName(encoding.GetString(header._fileName)); 

            header.Validate();

            return header; 
        }
 
        internal void Save(BinaryWriter writer) 
        {
            writer.Write(_signatureConstant); 
            writer.Write(_versionNeededToExtract);
            writer.Write(_generalPurposeBitFlag);
            writer.Write(_compressionMethod);
            writer.Write(_lastModFileDateTime); 
            writer.Write(_crc32);
            writer.Write(_compressedSize); 
            writer.Write(_uncompressedSize); 
            writer.Write(_fileNameLength);
            writer.Write(_extraField.Size); 

            if (_fileNameLength > 0)
            {
                writer.Write(_fileName, 0, _fileNameLength); 
            }
 
            _extraField.Save(writer); 

            writer.Flush(); 
        }

        internal UInt16 VersionNeededToExtract
        { 
            get
            { 
                return _versionNeededToExtract; 
            }
        } 

        internal UInt16 GeneralPurposeBitFlag
        {
            get 
            {
                return _generalPurposeBitFlag; 
            } 
        }
 
        internal CompressionMethodEnum CompressionMethod
        {
            get
            { 
                return (CompressionMethodEnum)_compressionMethod;
            } 
        } 

        internal UInt32 LastModFileDateTime 
        {
            get
            {
                return _lastModFileDateTime; 
            }
            set 
            { 
                _lastModFileDateTime = value;
            } 
        }

        internal UInt32 Crc32
        { 
            get
            { 
                return _crc32; 
            }
            set 
            {
                _crc32 = value;
            }
        } 

        internal long CompressedSize 
        { 
            get
            { 
                if ((_extraField.Zip64ExtraFieldUsage & ZipIOZip64ExtraFieldUsage.CompressedSize) != 0)
                {
                    // zip 64 extra field is there
                    return _extraField.CompressedSize; 
                }
                else 
                { 
                    // 32 bit case
                    return _compressedSize; 
                }
            }
        }
 
        internal long UncompressedSize
        { 
            get 
            {
                if ((_extraField.Zip64ExtraFieldUsage & ZipIOZip64ExtraFieldUsage.UncompressedSize) != 0) 
                {
                    // zip 64 extra field is there
                    return _extraField.UncompressedSize;
                } 
                else
                { 
                    // 32 bit case 
                    return _uncompressedSize;
                } 
            }
        }

        ///  
        /// FileName - already scrubbed via ValidateNormalizeFileName()
        ///  
        internal string FileName 
        {
            get 
            {
                return _stringFileName;
            }
        } 

        internal long Size 
        { 
            get
            { 
                return checked(_fixedMinimalRecordSize + _fileNameLength + _extraField.Size);
            }
        }
 
        internal bool StreamingCreationFlag
        { 
            get 
            {
                return ((_generalPurposeBitFlag & 0x8) != 0x0); 
            }
            set
            {
                if (value) 
                {
                    _generalPurposeBitFlag |= 0x8; //set bit #3 
                } 
                else
                { 
                    _generalPurposeBitFlag &= 0xFFF7; //clear bit #3
                }
            }
        } 

        internal DeflateOptionEnum DeflateOption 
        { 
            get
            { 
                if (CompressionMethod == CompressionMethodEnum.Deflated)
                {
                    return (DeflateOptionEnum)(_generalPurposeBitFlag & 0x6);
                } 
                else
                { 
                    // defalte option is validated to be one of the 2 (deflated or stored) 
                    return DeflateOptionEnum.None;
                } 
            }
            set
            {
                // this checks must be done in the levels above 
                Debug.Assert(Enum.IsDefined(typeof(DeflateOptionEnum), value));
                Debug.Assert(value != DeflateOptionEnum.None); 
 
                // clean the value (bits 1 and 2)
                _generalPurposeBitFlag &= 0xFFF9; 
                _generalPurposeBitFlag |= (UInt16)value; // safe cast because of the enum validation
            }
        }
 
        static internal int FixedMinimalRecordSize
        { 
            get 
            {
                return _fixedMinimalRecordSize; 
            }
        }

        private bool EncryptedFlag 
        {
            get 
            { 
                return ((_generalPurposeBitFlag & 0x1) == 0x1);
            } 
        }

        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);
            }
        } 

        internal void UpdatePadding(long headerSizeChange) 
        { 
            _extraField.UpdatePadding(headerSizeChange);
        } 

        private ZipIOLocalFileHeader()
        {
        } 

        private void Validate () 
        { 
            if (_signature != _signatureConstant)
            { 
                throw new FileFormatException(SR.Get(SRID.CorruptedData));
            }

            if (_fileNameLength != _fileName.Length) 
            {
                throw new FileFormatException(SR.Get(SRID.CorruptedData)); 
            } 

            ZipArchive.VerifyVersionNeededToExtract(_versionNeededToExtract); 

            // encryption is not supported
            if (EncryptedFlag)
                throw new NotSupportedException(SR.Get(SRID.ZipNotSupportedEncryptedArchive)); 

            // if verson is below 4.5 make sure that ZIP 64 extra filed isn't present 
            // if it is it might be a security concern 
            if ((_versionNeededToExtract < (UInt16)ZipIOVersionNeededToExtract.Zip64FileFormat) &&
                (_extraField.Zip64ExtraFieldUsage != ZipIOZip64ExtraFieldUsage.None)) 
            {
                throw new FileFormatException(SR.Get(SRID.CorruptedData));
            }
 
            // ZIP 64 validation; if extra field is present it
            // must have both compressed and uncompressed size in the local file header 
            // according to the appnote 
            if ((_extraField.Zip64ExtraFieldUsage != ZipIOZip64ExtraFieldUsage.None)  &&
                (_extraField.Zip64ExtraFieldUsage != 
                            (ZipIOZip64ExtraFieldUsage.CompressedSize |
                            ZipIOZip64ExtraFieldUsage.UncompressedSize)))
            {
                throw new FileFormatException(SR.Get(SRID.CorruptedData)); 
            }
 
            if (_extraFieldLength != _extraField.Size) 
            {
                throw new FileFormatException(SR.Get(SRID.CorruptedData)); 
            }

            if ((CompressionMethod != CompressionMethodEnum.Stored) &&
                (CompressionMethod != CompressionMethodEnum.Deflated)) 
            {
                throw new NotSupportedException(SR.Get(SRID.ZipNotSupportedCompressionMethod)); 
            } 
        }
 
        private const int _fixedMinimalRecordSize = 30;

        private const UInt32 _signatureConstant = 0x04034b50;
        private UInt32 _signature = _signatureConstant; 
        private UInt16 _versionNeededToExtract;
        private UInt16 _generalPurposeBitFlag; 
        private UInt16 _compressionMethod; 
        private UInt32 _lastModFileDateTime;
        private UInt32 _crc32; 
        private UInt32 _compressedSize;
        private UInt32 _uncompressedSize;
        private UInt16 _fileNameLength;
        private UInt16 _extraFieldLength; 
        private byte[] _fileName;
        private ZipIOExtraField _extraField; 
 
        private string _stringFileName;
        } 
}

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.
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