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// --- BEGIN COPYRIGHT BLOCK ---
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; version 2 of the License.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License along
// with this program; if not, write to the Free Software Foundation, Inc.,
// 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
//
// (C) 2007 Red Hat, Inc.
// All rights reserved.
// --- END COPYRIGHT BLOCK ---
package netscape.security.util;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.OutputStream;
/**
* DER input buffer ... this is the main abstraction in the DER library
* which actively works with the "untyped byte stream" abstraction. It
* does so with impunity, since it's not intended to be exposed to the
* anyone who could violate the "typed value stream" DER model and hence
* corrupt the input stream of DER values.
*
* @version 1.11
* @author David Brownell
*/
class DerInputBuffer extends ByteArrayInputStream implements Cloneable {
DerInputBuffer(byte[] buf) {
super(buf);
}
DerInputBuffer(byte[] buf, int offset, int len) {
super(buf, offset, len);
}
DerInputBuffer dup() {
try {
DerInputBuffer retval = (DerInputBuffer) clone();
retval.mark(Integer.MAX_VALUE);
return retval;
} catch (CloneNotSupportedException e) {
throw new IllegalArgumentException(e.toString());
}
}
byte[] toByteArray() throws IOException {
int len = available();
if (len <= 0)
throw new IOException("No Buffer Space Available.");
byte[] retval = new byte[len];
System.arraycopy(buf, pos, retval, 0, len);
return retval;
}
int peek() throws IOException {
if (pos >= count)
throw new IOException("out of data");
else
return buf[pos];
}
/**
* Compares this DerInputBuffer for equality with the specified
* object.
*/
public boolean equals(Object other) {
if (other instanceof DerInputBuffer)
return equals((DerInputBuffer) other);
else
return false;
}
boolean equals(DerInputBuffer other) {
if (this == other)
return true;
int max = this.available();
if (other.available() != max)
return false;
for (int i = 0; i < max; i++) {
if (this.buf[this.pos + i] != other.buf[other.pos + i]) {
return false;
}
}
return true;
}
void truncate(int len) throws IOException {
if (len > available())
throw new IOException("insufficient data");
count = pos + len;
}
/**
* Returns the unsigned integer which takes up the specified number
* of bytes in this buffer.
*/
BigInt getUnsigned(int len) throws IOException {
if (len > available())
throw new IOException("short read, getInteger");
/*
* A prepended zero is used to ensure that the integer is
* interpreted as unsigned even when the high order bit is
* zero. We don't support signed BigInts.
*
* Fix this here ... BigInts aren't expected to have these,
* and stuff like signing (sigsize = f(modulus)) misbehaves.
*/
if (len > 1 && buf[pos] == 0) {
len--;
skip(1);
}
/*
* Consume the rest of the buffer, returning its value as
* an unsigned integer.
*/
byte[] bytes = new byte[len];
System.arraycopy(buf, pos, bytes, 0, len);
skip(len);
return new BigInt(bytes);
}
/**
* Returns the bit string which takes up the rest of this buffer.
* This bit string must be byte-aligned.
*/
byte[] getBitString() {
if (pos >= count || buf[pos] != 0)
return null;
/*
* Just copy the data into an aligned, padded octet buffer,
* and consume the rest of the buffer.
*/
int len = available();
byte[] retval = new byte[len - 1];
System.arraycopy(buf, pos + 1, retval, 0, len - 1);
pos = count;
return retval;
}
/**
* Returns the bit string which takes up the rest of this buffer.
* The bit string need not be byte-aligned.
*/
BitArray getUnalignedBitString() {
if (pos >= count)
return null;
/*
* Just copy the data into an aligned, padded octet buffer,
* and consume the rest of the buffer.
*/
int len = available();
byte[] bits = new byte[len - 1];
int length = bits.length * 8 - buf[pos]; // number of valid bits
System.arraycopy(buf, pos + 1, bits, 0, len - 1);
BitArray bitArray = new BitArray(length, bits);
pos = count;
return bitArray;
}
/**
* Package-access method to optimize output operations
*/
void dump(OutputStream out, int length) throws IOException {
if (count < mark + length)
throw new IOException("short DER value (encode)");
out.write(buf, mark, length);
}
}
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