mirror of git://gcc.gnu.org/git/gcc.git
140 lines
3.7 KiB
Java
140 lines
3.7 KiB
Java
/* DERReader.java --
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Copyright (C) 1999, 2006 Free Software Foundation, Inc.
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This file is a part of GNU Classpath.
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GNU Classpath is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or (at
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your option) any later version.
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GNU Classpath is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GNU Classpath; if not, write to the Free Software
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Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301
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USA
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Linking this library statically or dynamically with other modules is
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making a combined work based on this library. Thus, the terms and
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conditions of the GNU General Public License cover the whole
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combination.
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As a special exception, the copyright holders of this library give you
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permission to link this library with independent modules to produce an
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executable, regardless of the license terms of these independent
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modules, and to copy and distribute the resulting executable under
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terms of your choice, provided that you also meet, for each linked
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independent module, the terms and conditions of the license of that
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module. An independent module is a module which is not derived from
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or based on this library. If you modify this library, you may extend
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this exception to your version of the library, but you are not
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obligated to do so. If you do not wish to do so, delete this
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exception statement from your version. */
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package gnu.javax.crypto.jce.params;
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import java.math.BigInteger;
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class DERReader
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{
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byte source[];
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int pos;
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static final int UNIVERSAL = 1;
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static final int APPLICATION = 2;
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static final int CONTEXT_SPECIFIC = 3;
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static final int PRIVATE = 4;
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public DERReader()
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{
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source = null;
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pos = 0;
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}
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public DERReader(byte source[])
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{
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init(source);
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}
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public void init(String source)
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{
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init(source.getBytes());
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}
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public void init(byte source[])
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{
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this.source = source;
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pos = 0;
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}
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public boolean hasMorePrimitives()
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{
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return pos < source.length;
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}
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public BigInteger getBigInteger() throws DEREncodingException
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{
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return new BigInteger(getPrimitive());
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}
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// Reads Primitive, definite-length method
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private byte[] getPrimitive() throws DEREncodingException
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{
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int tmp = pos;
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// Read Identifier
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byte identifier = source[tmp++];
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if ((0x20 & identifier) != 0)
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throw new DEREncodingException();
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int type = translateLeadIdentifierByte(identifier);
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// get tag
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int tag = (0x1f & identifier);
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// get length
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byte len = source[tmp]; // may be length of length parameter
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long length = 0x7f & len;
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int i;
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if ((0x80 & len) != 0)
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{
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len &= 0x7f;
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// get length here
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length = 0;
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for (i = 0; i < len; i++)
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{
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tmp++;
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length <<= 8;
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length += (source[tmp] < 0) ? (256 + source[tmp]) : source[tmp];
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}
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tmp++;
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}
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else
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tmp++;
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byte tmpb[] = new byte[(int) length];
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System.arraycopy(source, tmp, tmpb, 0, (int) length);
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pos = (int) (tmp + length);
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return tmpb;
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}
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private int translateLeadIdentifierByte(byte b)
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{
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if ((0x3f & b) == b)
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return UNIVERSAL;
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else if ((0x7f & b) == b)
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return APPLICATION;
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else if ((0xbf & b) == b)
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return CONTEXT_SPECIFIC;
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else
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return PRIVATE;
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}
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private int getIdentifier(int tpos)
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{
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while ((0x80 & source[tpos]) != 0)
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tpos++;
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return tpos;
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}
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}
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