package org.bouncycastle.asn1;

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

import org.bouncycastle.util.io.Streams;

Parse data stream of expected ASN.1 data expecting definite-length encoding..
/** * Parse data stream of expected ASN.1 data expecting definite-length encoding.. */
class DefiniteLengthInputStream extends LimitedInputStream { private static final byte[] EMPTY_BYTES = new byte[0]; private final int _originalLength; private int _remaining; DefiniteLengthInputStream( InputStream in, int length) { super(in, length); if (length < 0) { throw new IllegalArgumentException("negative lengths not allowed"); } this._originalLength = length; this._remaining = length; if (length == 0) { setParentEofDetect(true); } } int getRemaining() { return _remaining; } public int read() throws IOException { if (_remaining == 0) { return -1; } int b = _in.read(); if (b < 0) { throw new EOFException("DEF length " + _originalLength + " object truncated by " + _remaining); } if (--_remaining == 0) { setParentEofDetect(true); } return b; } public int read(byte[] buf, int off, int len) throws IOException { if (_remaining == 0) { return -1; } int toRead = Math.min(len, _remaining); int numRead = _in.read(buf, off, toRead); if (numRead < 0) { throw new EOFException("DEF length " + _originalLength + " object truncated by " + _remaining); } if ((_remaining -= numRead) == 0) { setParentEofDetect(true); } return numRead; } byte[] toByteArray() throws IOException { if (_remaining == 0) { return EMPTY_BYTES; } byte[] bytes = new byte[_remaining]; if ((_remaining -= Streams.readFully(_in, bytes)) != 0) { throw new EOFException("DEF length " + _originalLength + " object truncated by " + _remaining); } setParentEofDetect(true); return bytes; } }