| /* DERReader.java -- |
| Copyright (C) 1999, 2006 Free Software Foundation, Inc. |
| |
| This file is a part of GNU Classpath. |
| |
| GNU Classpath 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; either version 2 of the License, or (at |
| your option) any later version. |
| |
| GNU Classpath 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 GNU Classpath; if not, write to the Free Software |
| Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 |
| USA |
| |
| Linking this library statically or dynamically with other modules is |
| making a combined work based on this library. Thus, the terms and |
| conditions of the GNU General Public License cover the whole |
| combination. |
| |
| As a special exception, the copyright holders of this library give you |
| permission to link this library with independent modules to produce an |
| executable, regardless of the license terms of these independent |
| modules, and to copy and distribute the resulting executable under |
| terms of your choice, provided that you also meet, for each linked |
| independent module, the terms and conditions of the license of that |
| module. An independent module is a module which is not derived from |
| or based on this library. If you modify this library, you may extend |
| this exception to your version of the library, but you are not |
| obligated to do so. If you do not wish to do so, delete this |
| exception statement from your version. */ |
| |
| |
| package gnu.javax.crypto.jce.params; |
| |
| import java.math.BigInteger; |
| |
| class DERReader |
| { |
| byte source[]; |
| int pos; |
| static final int UNIVERSAL = 1; |
| static final int APPLICATION = 2; |
| static final int CONTEXT_SPECIFIC = 3; |
| static final int PRIVATE = 4; |
| |
| public DERReader() |
| { |
| source = null; |
| pos = 0; |
| } |
| |
| public DERReader(byte source[]) |
| { |
| init(source); |
| } |
| |
| public void init(String source) |
| { |
| init(source.getBytes()); |
| } |
| |
| public void init(byte source[]) |
| { |
| this.source = source; |
| pos = 0; |
| } |
| |
| public boolean hasMorePrimitives() |
| { |
| return pos < source.length; |
| } |
| |
| public BigInteger getBigInteger() throws DEREncodingException |
| { |
| return new BigInteger(getPrimitive()); |
| } |
| |
| // Reads Primitive, definite-length method |
| private byte[] getPrimitive() throws DEREncodingException |
| { |
| int tmp = pos; |
| // Read Identifier |
| byte identifier = source[tmp++]; |
| if ((0x20 & identifier) != 0) |
| throw new DEREncodingException(); |
| int type = translateLeadIdentifierByte(identifier); |
| // get tag |
| int tag = (0x1f & identifier); |
| // get length |
| byte len = source[tmp]; // may be length of length parameter |
| long length = 0x7f & len; |
| int i; |
| if ((0x80 & len) != 0) |
| { |
| len &= 0x7f; |
| // get length here |
| length = 0; |
| for (i = 0; i < len; i++) |
| { |
| tmp++; |
| length <<= 8; |
| length += (source[tmp] < 0) ? (256 + source[tmp]) : source[tmp]; |
| } |
| tmp++; |
| } |
| else |
| tmp++; |
| |
| byte tmpb[] = new byte[(int) length]; |
| System.arraycopy(source, tmp, tmpb, 0, (int) length); |
| pos = (int) (tmp + length); |
| return tmpb; |
| } |
| |
| private int translateLeadIdentifierByte(byte b) |
| { |
| if ((0x3f & b) == b) |
| return UNIVERSAL; |
| else if ((0x7f & b) == b) |
| return APPLICATION; |
| else if ((0xbf & b) == b) |
| return CONTEXT_SPECIFIC; |
| else |
| return PRIVATE; |
| } |
| |
| private int getIdentifier(int tpos) |
| { |
| while ((0x80 & source[tpos]) != 0) |
| tpos++; |
| return tpos; |
| } |
| } |