493 lines
13 KiB
C#
493 lines
13 KiB
C#
using System;
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using System.Collections;
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using System.IO;
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using System.Text;
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using Org.BouncyCastle.Utilities.IO;
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namespace Org.BouncyCastle.Bcpg
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{
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/**
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* reader for Base64 armored objects - read the headers and then start returning
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* bytes when the data is reached. An IOException is thrown if the CRC check
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* fails.
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*/
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public class ArmoredInputStream
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: BaseInputStream
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{
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/*
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* set up the decoding table.
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*/
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private readonly static byte[] decodingTable;
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static ArmoredInputStream()
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{
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decodingTable = new byte[128];
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for (int i = 'A'; i <= 'Z'; i++)
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{
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decodingTable[i] = (byte)(i - 'A');
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}
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for (int i = 'a'; i <= 'z'; i++)
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{
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decodingTable[i] = (byte)(i - 'a' + 26);
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}
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for (int i = '0'; i <= '9'; i++)
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{
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decodingTable[i] = (byte)(i - '0' + 52);
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}
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decodingTable['+'] = 62;
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decodingTable['/'] = 63;
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}
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/**
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* decode the base 64 encoded input data.
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*
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* @return the offset the data starts in out.
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*/
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private int Decode(
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int in0,
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int in1,
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int in2,
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int in3,
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int[] result)
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{
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if (in3 < 0)
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{
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throw new EndOfStreamException("unexpected end of file in armored stream.");
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}
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int b1, b2, b3, b4;
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if (in2 == '=')
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{
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b1 = decodingTable[in0] &0xff;
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b2 = decodingTable[in1] & 0xff;
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result[2] = ((b1 << 2) | (b2 >> 4)) & 0xff;
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return 2;
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}
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else if (in3 == '=')
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{
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b1 = decodingTable[in0];
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b2 = decodingTable[in1];
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b3 = decodingTable[in2];
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result[1] = ((b1 << 2) | (b2 >> 4)) & 0xff;
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result[2] = ((b2 << 4) | (b3 >> 2)) & 0xff;
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return 1;
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}
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else
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{
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b1 = decodingTable[in0];
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b2 = decodingTable[in1];
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b3 = decodingTable[in2];
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b4 = decodingTable[in3];
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result[0] = ((b1 << 2) | (b2 >> 4)) & 0xff;
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result[1] = ((b2 << 4) | (b3 >> 2)) & 0xff;
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result[2] = ((b3 << 6) | b4) & 0xff;
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return 0;
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}
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}
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Stream input;
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bool start = true;
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int[] outBuf = new int[3];
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int bufPtr = 3;
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Crc24 crc = new Crc24();
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bool crcFound = false;
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bool hasHeaders = true;
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string header = null;
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bool newLineFound = false;
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bool clearText = false;
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bool restart = false;
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ArrayList headerList= new ArrayList();
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int lastC = 0;
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/**
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* Create a stream for reading a PGP armoured message, parsing up to a header
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* and then reading the data that follows.
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*
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* @param input
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*/
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public ArmoredInputStream(
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Stream input)
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: this(input, true)
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{
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}
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/**
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* Create an armoured input stream which will assume the data starts
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* straight away, or parse for headers first depending on the value of
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* hasHeaders.
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*
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* @param input
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* @param hasHeaders true if headers are to be looked for, false otherwise.
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*/
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public ArmoredInputStream(
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Stream input,
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bool hasHeaders)
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{
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this.input = input;
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this.hasHeaders = hasHeaders;
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if (hasHeaders)
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{
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ParseHeaders();
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}
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start = false;
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}
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private bool ParseHeaders()
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{
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header = null;
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int c;
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int last = 0;
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bool headerFound = false;
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headerList = new ArrayList();
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//
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// if restart we already have a header
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//
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if (restart)
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{
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headerFound = true;
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}
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else
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{
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while ((c = input.ReadByte()) >= 0)
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{
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if (c == '-' && (last == 0 || last == '\n' || last == '\r'))
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{
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headerFound = true;
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break;
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}
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last = c;
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}
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}
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if (headerFound)
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{
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StringBuilder Buffer = new StringBuilder("-");
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bool eolReached = false;
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bool crLf = false;
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if (restart) // we've had to look ahead two '-'
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{
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Buffer.Append('-');
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}
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while ((c = input.ReadByte()) >= 0)
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{
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if (last == '\r' && c == '\n')
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{
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crLf = true;
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}
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if (eolReached && (last != '\r' && c == '\n'))
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{
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break;
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}
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if (eolReached && c == '\r')
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{
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break;
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}
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if (c == '\r' || (last != '\r' && c == '\n'))
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{
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string line = Buffer.ToString();
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if (line.Trim().Length < 1)
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break;
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headerList.Add(line);
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Buffer.Length = 0;
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}
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if (c != '\n' && c != '\r')
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{
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Buffer.Append((char)c);
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eolReached = false;
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}
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else
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{
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if (c == '\r' || (last != '\r' && c == '\n'))
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{
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eolReached = true;
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}
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}
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last = c;
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}
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if (crLf)
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{
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input.ReadByte(); // skip last \n
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}
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}
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if (headerList.Count > 0)
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{
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header = (string) headerList[0];
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}
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clearText = "-----BEGIN PGP SIGNED MESSAGE-----".Equals(header);
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newLineFound = true;
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return headerFound;
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}
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/**
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* @return true if we are inside the clear text section of a PGP
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* signed message.
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*/
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public bool IsClearText()
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{
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return clearText;
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}
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/**
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* Return the armor header line (if there is one)
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* @return the armor header line, null if none present.
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*/
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public string GetArmorHeaderLine()
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{
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return header;
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}
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/**
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* Return the armor headers (the lines after the armor header line),
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* @return an array of armor headers, null if there aren't any.
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*/
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public string[] GetArmorHeaders()
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{
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if (headerList.Count <= 1)
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{
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return null;
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}
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string[] hdrs = new string[headerList.Count - 1];
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for (int i = 0; i != hdrs.Length; i++)
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{
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hdrs[i] = (string) headerList[i + 1];
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}
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return hdrs;
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}
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private int ReadIgnoreSpace()
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{
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int c;
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do
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{
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c = input.ReadByte();
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}
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while (c == ' ' || c == '\t');
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return c;
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}
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private int ReadIgnoreWhitespace()
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{
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int c;
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do
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{
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c = input.ReadByte();
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}
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while (c == ' ' || c == '\t' || c == '\r' || c == '\n');
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return c;
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}
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private int ReadByteClearText()
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{
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int c = input.ReadByte();
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if (c == '\r' || (c == '\n' && lastC != '\r'))
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{
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newLineFound = true;
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}
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else if (newLineFound && c == '-')
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{
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c = input.ReadByte();
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if (c == '-') // a header, not dash escaped
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{
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clearText = false;
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start = true;
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restart = true;
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}
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else // a space - must be a dash escape
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{
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c = input.ReadByte();
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}
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newLineFound = false;
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}
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else
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{
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if (c != '\n' && lastC != '\r')
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{
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newLineFound = false;
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}
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}
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lastC = c;
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return c;
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}
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private int ReadClearText(byte[] buffer, int offset, int count)
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{
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int pos = offset;
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try
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{
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int end = offset + count;
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while (pos < end)
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{
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int c = ReadByteClearText();
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if (c == -1)
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{
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break;
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}
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buffer[pos++] = (byte) c;
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}
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}
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catch (IOException ioe)
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{
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if (pos == offset) throw ioe;
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}
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return pos - offset;
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}
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private int DoReadByte()
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{
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if (bufPtr > 2 || crcFound)
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{
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int c = ReadIgnoreSpace();
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if (c == '\n' || c == '\r')
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{
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c = ReadIgnoreWhitespace();
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if (c == '=') // crc reached
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{
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bufPtr = Decode(ReadIgnoreSpace(), ReadIgnoreSpace(), ReadIgnoreSpace(), ReadIgnoreSpace(), outBuf);
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if (bufPtr != 0)
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{
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throw new IOException("no crc found in armored message.");
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}
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crcFound = true;
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int i = ((outBuf[0] & 0xff) << 16)
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| ((outBuf[1] & 0xff) << 8)
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| (outBuf[2] & 0xff);
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if (i != crc.Value)
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{
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throw new IOException("crc check failed in armored message.");
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}
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return ReadByte();
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}
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if (c == '-') // end of record reached
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{
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while ((c = input.ReadByte()) >= 0)
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{
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if (c == '\n' || c == '\r')
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{
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break;
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}
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}
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if (!crcFound)
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{
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throw new IOException("crc check not found.");
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}
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crcFound = false;
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start = true;
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bufPtr = 3;
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return -1;
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}
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}
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if (c < 0)
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{
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return -1;
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}
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bufPtr = Decode(c, ReadIgnoreSpace(), ReadIgnoreSpace(), ReadIgnoreSpace(), outBuf);
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}
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return outBuf[bufPtr++];
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}
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public override int ReadByte()
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{
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if (start)
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{
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if (hasHeaders)
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{
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ParseHeaders();
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}
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crc.Reset();
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start = false;
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}
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if (clearText)
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{
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return ReadByteClearText();
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}
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int c = DoReadByte();
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crc.Update(c);
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return c;
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}
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public override int Read(byte[] buffer, int offset, int count)
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{
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if (start && count > 0)
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{
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if (hasHeaders)
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{
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ParseHeaders();
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}
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start = false;
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}
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if (clearText)
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{
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return ReadClearText(buffer, offset, count);
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}
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int pos = offset;
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try
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{
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int end = offset + count;
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while (pos < end)
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{
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int c = DoReadByte();
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crc.Update(c);
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if (c == -1)
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{
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break;
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}
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buffer[pos++] = (byte) c;
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}
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}
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catch (IOException ioe)
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{
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if (pos == offset) throw ioe;
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}
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return pos - offset;
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}
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public override void Close()
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{
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input.Close();
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base.Close();
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}
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}
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}
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