| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You under the Apache License, Version 2.0 |
| * (the "License"); you may not use this file except in compliance with |
| * the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| /** |
| * @author Alexey V. Varlamov, Stepan M. Mishura |
| * @version $Revision$ |
| */ |
| |
| package org.apache.harmony.security.asn1; |
| |
| /** |
| * Represents ASN.1 bit string value |
| * |
| * @see <a href="http://asn1.elibel.tm.fr/en/standards/index.htm">ASN.1</a> |
| */ |
| public final class BitString { |
| |
| private static final byte[] SET_MASK = { (byte) 128, 64, 32, 16, 8, 4, 2, 1 }; |
| |
| private static final byte[] RESET_MASK = { 0x7f, (byte) 0xbf, (byte) 0xdf, |
| (byte) 0xef, (byte) 0xf7, (byte) 0xfb, (byte) 0xfd, (byte) 0xfe, }; |
| |
| /** Sequence of bits padded with unused bits. */ |
| public final byte[] bytes; |
| |
| /** Number of unused bits in the last byte. */ |
| public final int unusedBits; |
| |
| /** |
| * @param bytes array of bytes that represents bit string, |
| * including unused bits |
| * @param unusedBits number of unused bits |
| * @throws IllegalArgumentException - if parameters are invalid |
| */ |
| public BitString(byte[] bytes, int unusedBits) { |
| // constraints are set according X.690 |
| if (unusedBits < 0 || unusedBits > 7) { |
| throw new IllegalArgumentException("Number of unused bits MUST be in range 0-7"); |
| } |
| |
| if (bytes.length == 0 && unusedBits != 0) { |
| throw new IllegalArgumentException("For empty bit string unused bits MUST be 0"); |
| } |
| |
| this.bytes = bytes; |
| this.unusedBits = unusedBits; |
| } |
| |
| public BitString(boolean[] values) { |
| unusedBits = values.length % 8; |
| int size = values.length / 8; |
| if (unusedBits != 0) { |
| size++; |
| } |
| bytes = new byte[size]; |
| for (int i = 0; i < values.length; i++) { |
| setBit(i, values[i]); |
| } |
| } |
| |
| public boolean getBit(int bit) { |
| int offset = bit % 8; |
| int index = bit / 8; |
| return (bytes[index] & SET_MASK[offset]) != 0; |
| } |
| |
| public void setBit(int bit, boolean value) { |
| int offset = bit % 8; |
| int index = bit / 8; |
| if (value) { |
| bytes[index] |= SET_MASK[offset]; |
| } else { |
| bytes[index] &= RESET_MASK[offset]; |
| } |
| } |
| |
| public boolean[] toBooleanArray() { |
| boolean[] result = new boolean[bytes.length * 8 - unusedBits]; |
| for (int i = 0; i < result.length; i++) { |
| result[i] = getBit(i); |
| } |
| return result; |
| } |
| } |