package org.spongycastle.bcpg;
import java.io.*;
import java.util.Vector;
/**
* 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
extends InputStream
{
/*
* set up the decoding table.
*/
private static final byte[] decodingTable;
static
{
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[] out)
throws EOFException
{
int b1, b2, b3, b4;
if (in3 < 0)
{
throw new EOFException("unexpected end of file in armored stream.");
}
if (in2 == '=')
{
b1 = decodingTable[in0] &0xff;
b2 = decodingTable[in1] & 0xff;
out[2] = ((b1 << 2) | (b2 >> 4)) & 0xff;
return 2;
}
else if (in3 == '=')
{
b1 = decodingTable[in0];
b2 = decodingTable[in1];
b3 = decodingTable[in2];
out[1] = ((b1 << 2) | (b2 >> 4)) & 0xff;
out[2] = ((b2 << 4) | (b3 >> 2)) & 0xff;
return 1;
}
else
{
b1 = decodingTable[in0];
b2 = decodingTable[in1];
b3 = decodingTable[in2];
b4 = decodingTable[in3];
out[0] = ((b1 << 2) | (b2 >> 4)) & 0xff;
out[1] = ((b2 << 4) | (b3 >> 2)) & 0xff;
out[2] = ((b3 << 6) | b4) & 0xff;
return 0;
}
}
InputStream in;
boolean start = true;
int[] outBuf = new int[3];
int bufPtr = 3;
CRC24 crc = new CRC24();
boolean crcFound = false;
boolean hasHeaders = true;
String header = null;
boolean newLineFound = false;
boolean clearText = false;
boolean restart = false;
Vector headerList= new Vector();
int lastC = 0;
boolean isEndOfStream;
/**
* Create a stream for reading a PGP armoured message, parsing up to a header
* and then reading the data that follows.
*
* @param in
*/
public ArmoredInputStream(
InputStream in)
throws IOException
{
this(in, 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 in
* @param hasHeaders true if headers are to be looked for, false otherwise.
*/
public ArmoredInputStream(
InputStream in,
boolean hasHeaders)
throws IOException
{
this.in = in;
this.hasHeaders = hasHeaders;
if (hasHeaders)
{
parseHeaders();
}
start = false;
}
public int available()
throws IOException
{
return in.available();
}
private boolean parseHeaders()
throws IOException
{
header = null;
int c;
int last = 0;
boolean headerFound = false;
headerList = new Vector();
//
// if restart we already have a header
//
if (restart)
{
headerFound = true;
}
else
{
while ((c = in.read()) >= 0)
{
if (c == '-' && (last == 0 || last == '\n' || last == '\r'))
{
headerFound = true;
break;
}
last = c;
}
}
if (headerFound)
{
StringBuffer buf = new StringBuffer("-");
boolean eolReached = false;
boolean crLf = false;
if (restart) // we've had to look ahead two '-'
{
buf.append('-');
}
while ((c = in.read()) >= 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 = buf.toString();
if (line.trim().length() == 0)
{
break;
}
headerList.addElement(line);
buf.setLength(0);
}
if (c != '\n' && c != '\r')
{
buf.append((char)c);
eolReached = false;
}
else
{
if (c == '\r' || (last != '\r' && c == '\n'))
{
eolReached = true;
}
}
last = c;
}
if (crLf)
{
in.read(); // skip last \n
}
}
if (headerList.size() > 0)
{
header = (String)headerList.elementAt(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 boolean isClearText()
{
return clearText;
}
/**
* @return true if the stream is actually at end of file.
*/
public boolean 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.size() <= 1)
{
return null;
}
String[] hdrs = new String[headerList.size() - 1];
for (int i = 0; i != hdrs.length; i++)
{
hdrs[i] = (String)headerList.elementAt(i + 1);
}
return hdrs;
}
private int readIgnoreSpace()
throws IOException
{
int c = in.read();
while (c == ' ' || c == '\t')
{
c = in.read();
}
return c;
}
public int read()
throws IOException
{
int c;
if (start)
{
if (hasHeaders)
{
parseHeaders();
}
crc.reset();
start = false;
}
if (clearText)
{
c = in.read();
if (c == '\r' || (c == '\n' && lastC != '\r'))
{
newLineFound = true;
}
else if (newLineFound && c == '-')
{
c = in.read();
if (c == '-') // a header, not dash escaped
{
clearText = false;
start = true;
restart = true;
}
else // a space - must be a dash escape
{
c = in.read();
}
newLineFound = false;
}
else
{
if (c != '\n' && lastC != '\r')
{
newLineFound = false;
}
}
lastC = c;
if (c < 0)
{
isEndOfStream = true;
}
return c;
}
if (bufPtr > 2 || crcFound)
{
c = readIgnoreSpace();
if (c == '\r' || c == '\n')
{
c = readIgnoreSpace();
while (c == '\n' || c == '\r')
{
c = readIgnoreSpace();
}
if (c < 0) // EOF
{
isEndOfStream = true;
return -1;
}
if (c == '=') // crc reached
{
bufPtr = decode(readIgnoreSpace(), readIgnoreSpace(), readIgnoreSpace(), readIgnoreSpace(), outBuf);
if (bufPtr == 0)
{
int i = ((outBuf[0] & 0xff) << 16)
| ((outBuf[1] & 0xff) << 8)
| (outBuf[2] & 0xff);
crcFound = true;
if (i != crc.getValue())
{
throw new IOException("crc check failed in armored message.");
}
return read();
}
else
{
throw new IOException("no crc found in armored message.");
}
}
else if (c == '-') // end of record reached
{
while ((c = in.read()) >= 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;
}
else // data
{
bufPtr = decode(c, readIgnoreSpace(), readIgnoreSpace(), readIgnoreSpace(), outBuf);
}
}
else
{
if (c >= 0)
{
bufPtr = decode(c, readIgnoreSpace(), readIgnoreSpace(), readIgnoreSpace(), outBuf);
}
else
{
isEndOfStream = true;
return -1;
}
}
}
c = outBuf[bufPtr++];
crc.update(c);
return c;
}
public void close()
throws IOException
{
in.close();
}
}