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