102 lines
4.0 KiB
C#
102 lines
4.0 KiB
C#
//
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// Copyright (c) 2008-2011, Kenneth Bell
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//
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// Permission is hereby granted, free of charge, to any person obtaining a
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// copy of this software and associated documentation files (the "Software"),
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// to deal in the Software without restriction, including without limitation
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// the rights to use, copy, modify, merge, publish, distribute, sublicense,
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// and/or sell copies of the Software, and to permit persons to whom the
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// Software is furnished to do so, subject to the following conditions:
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//
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// The above copyright notice and this permission notice shall be included in
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// all copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
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// DEALINGS IN THE SOFTWARE.
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//
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using System;
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using DiscUtils.Streams;
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namespace DiscUtils.Archives
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{
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internal sealed class TarHeader
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{
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public const int Length = 512;
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public long FileLength;
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public UnixFilePermissions FileMode;
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public string FileName;
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public int GroupId;
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public DateTime ModificationTime;
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public int OwnerId;
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public void ReadFrom(byte[] buffer, int offset)
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{
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FileName = ReadNullTerminatedString(buffer, offset + 0, 100);
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FileMode = (UnixFilePermissions)OctalToLong(ReadNullTerminatedString(buffer, offset + 100, 8));
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OwnerId = (int)OctalToLong(ReadNullTerminatedString(buffer, offset + 108, 8));
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GroupId = (int)OctalToLong(ReadNullTerminatedString(buffer, offset + 116, 8));
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FileLength = OctalToLong(ReadNullTerminatedString(buffer, offset + 124, 12));
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ModificationTime = OctalToLong(ReadNullTerminatedString(buffer, offset + 136, 12)).FromUnixTimeSeconds().DateTime;
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}
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public void WriteTo(byte[] buffer, int offset)
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{
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Array.Clear(buffer, offset, Length);
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EndianUtilities.StringToBytes(FileName, buffer, offset, 99);
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EndianUtilities.StringToBytes(LongToOctal((long)FileMode, 7), buffer, offset + 100, 7);
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EndianUtilities.StringToBytes(LongToOctal(OwnerId, 7), buffer, offset + 108, 7);
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EndianUtilities.StringToBytes(LongToOctal(GroupId, 7), buffer, offset + 116, 7);
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EndianUtilities.StringToBytes(LongToOctal(FileLength, 11), buffer, offset + 124, 11);
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EndianUtilities.StringToBytes(LongToOctal(Convert.ToUInt32((new DateTimeOffset(ModificationTime)).ToUnixTimeSeconds()), 11), buffer, offset + 136, 11);
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// Checksum
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EndianUtilities.StringToBytes(new string(' ', 8), buffer, offset + 148, 8);
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long checkSum = 0;
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for (int i = 0; i < 512; ++i)
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{
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checkSum += buffer[offset + i];
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}
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EndianUtilities.StringToBytes(LongToOctal(checkSum, 7), buffer, offset + 148, 7);
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buffer[155] = 0;
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}
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private static string ReadNullTerminatedString(byte[] buffer, int offset, int length)
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{
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return EndianUtilities.BytesToString(buffer, offset, length).TrimEnd('\0');
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}
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private static long OctalToLong(string value)
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{
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long result = 0;
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for (int i = 0; i < value.Length; ++i)
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{
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result = result * 8 + (value[i] - '0');
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}
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return result;
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}
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private static string LongToOctal(long value, int length)
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{
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string result = string.Empty;
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while (value > 0)
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{
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result = (char)('0' + value % 8) + result;
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value = value / 8;
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}
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return new string('0', length - result.Length) + result;
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}
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}
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} |