1 /* 2 * Licensed to the Apache Software Foundation (ASF) under one or more 3 * contributor license agreements. See the NOTICE file distributed with 4 * this work for additional information regarding copyright ownership. 5 * The ASF licenses this file to You under the Apache License, Version 2.0 6 * (the "License"); you may not use this file except in compliance with 7 * the License. You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 */ 17 18 /** 19 * @author Vladimir N. Molotkov, Stepan M. Mishura 20 * @version $Revision$ 21 */ 22 23 package org.apache.harmony.security.asn1; 24 25 import java.io.IOException; 26 import libcore.util.EmptyArray; 27 28 /** 29 * This class represents ASN.1 Bitstring type. 30 * 31 * @see <a href="http://asn1.elibel.tm.fr/en/standards/index.htm">ASN.1</a> 32 */ 33 public class ASN1BitString extends ASN1StringType { 34 35 // default implementation 36 private static final ASN1BitString ASN1 = new ASN1BitString(); 37 38 /** 39 * Constructs ASN.1 Bitstring type 40 * 41 * The constructor is provided for inheritance purposes 42 * when there is a need to create a custom ASN.1 Bitstring type. 43 * To get a default implementation it is recommended to use 44 * getInstance() method. 45 */ 46 public ASN1BitString() { 47 super(TAG_BITSTRING); 48 } 49 50 /** 51 * Returns ASN.1 Bitstring type default implementation 52 * 53 * The default implementation works with encoding 54 * that is represented as BitString object. 55 * 56 * @return ASN.1 Bitstring type default implementation 57 * @see org.apache.harmony.security.asn1.BitString 58 */ 59 public static ASN1BitString getInstance() { 60 return ASN1; 61 } 62 63 @Override public Object decode(BerInputStream in) throws IOException { 64 in.readBitString(); 65 66 if (in.isVerify) { 67 return null; 68 } 69 return getDecodedObject(in); 70 } 71 72 /** 73 * Extracts BitString object from BER input stream. 74 * 75 * @param in - BER input stream 76 * @return BitString object 77 */ 78 @Override public Object getDecodedObject(BerInputStream in) throws IOException { 79 byte[] bytes = new byte[in.length - 1]; 80 System.arraycopy(in.buffer, in.contentOffset + 1, bytes, 0, 81 in.length - 1); 82 return new BitString(bytes, in.buffer[in.contentOffset]); 83 } 84 85 @Override public void encodeContent(BerOutputStream out) { 86 out.encodeBitString(); 87 } 88 89 @Override public void setEncodingContent(BerOutputStream out) { 90 out.length = ((BitString) out.content).bytes.length + 1; 91 } 92 93 /** 94 * Default implementation for ASN.1 Named Bitstring type 95 * 96 * The default implementation works with encoding 97 * that is mapped to array of boolean. 98 */ 99 public static class ASN1NamedBitList extends ASN1BitString { 100 private static final byte[] SET_MASK = { (byte) 128, 64, 32, 16, 8, 4, 2, 1}; 101 private static final BitString emptyString = new BitString(EmptyArray.BYTE, 0); 102 private static final int INDEFINITE_SIZE = -1; 103 104 private final int minBits; 105 private final int maxBits; 106 107 public ASN1NamedBitList(int minBits) { 108 this.minBits = minBits; 109 this.maxBits = INDEFINITE_SIZE; 110 } 111 112 @Override public Object getDecodedObject(BerInputStream in) throws IOException { 113 boolean[] value; 114 115 int unusedBits = in.buffer[in.contentOffset]; 116 int bitsNumber = (in.length - 1) * 8 - unusedBits; 117 118 if (maxBits == INDEFINITE_SIZE) { 119 if (minBits == INDEFINITE_SIZE) { 120 value = new boolean[bitsNumber]; 121 } else { 122 if (bitsNumber > minBits) { 123 value = new boolean[bitsNumber]; 124 } else { 125 value = new boolean[minBits]; 126 } 127 } 128 } else { 129 if (bitsNumber > maxBits) { 130 throw new ASN1Exception("ASN.1 Named Bitstring: size constraints"); 131 } 132 value = new boolean[maxBits]; 133 } 134 135 if (bitsNumber == 0) { 136 // empty bit string 137 return value; 138 } 139 140 int i = 1; 141 int j = 0; 142 byte octet = in.buffer[in.contentOffset + i]; 143 for (int size = in.length - 1; i < size; i++) { 144 for (int k = 0; k < 8; k++, j++) { 145 value[j] = (SET_MASK[k] & octet) != 0; 146 } 147 i++; 148 octet = in.buffer[in.contentOffset + i]; 149 } 150 151 // final octet 152 for (int k = 0; k < (8 - unusedBits); k++, j++) { 153 value[j] = (SET_MASK[k] & octet) != 0; 154 } 155 156 return value; 157 } 158 159 @Override public void setEncodingContent(BerOutputStream out) { 160 boolean[] toEncode = (boolean[]) out.content; 161 162 int index = toEncode.length - 1; 163 while (index > -1 && !toEncode[index]) { 164 index--; 165 } 166 167 if (index == -1) { 168 out.content = emptyString; 169 out.length = 1; 170 } else { 171 int unusedBits = 7 - index % 8; 172 byte[] bytes = new byte[index / 8 + 1]; 173 174 int j = 0; 175 index = bytes.length - 1; 176 for (int i = 0; i < index; i++) { 177 for (int k = 0; k < 8; k++, j++) { 178 if (toEncode[j]) { 179 bytes[i] = (byte) (bytes[i] | SET_MASK[k]); 180 } 181 } 182 } 183 184 //final octet 185 for (int k = 0; k < (8 - unusedBits); k++, j++) { 186 if (toEncode[j]) { 187 bytes[index] = (byte) (bytes[index] | SET_MASK[k]); 188 } 189 } 190 191 out.content = new BitString(bytes, unusedBits); 192 out.length = bytes.length + 1; 193 } 194 } 195 } 196 } 197