org.bouncycastle.bcpg.UserAttributeSubpacketInputStream Maven / Gradle / Ivy

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The Bouncy Castle Java APIs for the OpenPGP Protocol. The APIs are designed primarily to be used in conjunction with the BC FIPS provider. The APIs may also be used with other providers although if being used in a FIPS context it is the responsibility of the user to ensure that any other providers used are FIPS certified and used appropriately.

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package org.bouncycastle.bcpg;

import java.io.EOFException;
import java.io.IOException;
import java.io.InputStream;

import org.bouncycastle.bcpg.attr.ImageAttribute;

/**
 * reader for user attribute sub-packets
 */
public class UserAttributeSubpacketInputStream
    extends InputStream implements UserAttributeSubpacketTags
{
    InputStream    in;
    
    public UserAttributeSubpacketInputStream(
        InputStream    in)
    {
        this.in = in;
    }
    
    public int available()
        throws IOException
    {
        return in.available();
    }
    
    public int read()
        throws IOException
    {
        return in.read();
    }
    
    private void readFully(
        byte[]    buf,
        int       off,
        int       len)
        throws IOException
    {
        if (len > 0)
        {
            int    b = this.read();
            
            if (b < 0)
            {
                throw new EOFException();
            }
            
            buf[off] = (byte)b;
            off++;
            len--;
        }
        
        while (len > 0)
        {
            int    l = in.read(buf, off, len);
            
            if (l < 0)
            {
                throw new EOFException();
            }
            
            off += l;
            len -= l;
        }
    }
    
    public UserAttributeSubpacket readPacket()
        throws IOException
    {
        int            l = this.read();
        int            bodyLen = 0;
        boolean        longLength = false;

        if (l < 0)
        {
            return null;
        }

        if (l < 192)
        {
            bodyLen = l;
        }
        else if (l <= 223)
        {
            bodyLen = ((l - 192) << 8) + (in.read()) + 192;
        }
        else if (l == 255)
        {
            bodyLen = (in.read() << 24) | (in.read() << 16) |  (in.read() << 8)  | in.read();
            longLength = true;
        }
        else
        {
            throw new IOException("unrecognised length reading user attribute sub packet");
        }

       int        tag = in.read();

       if (tag < 0)
       {
           throw new EOFException("unexpected EOF reading user attribute sub packet");
       }
       
       byte[]    data = new byte[bodyLen - 1];

       this.readFully(data, 0, data.length);
       
       int       type = tag;

       switch (type)
       {
       case IMAGE_ATTRIBUTE:
           return new ImageAttribute(longLength, data);
       }

       return new UserAttributeSubpacket(type, longLength, data);
    }
}