DERInteger.java revision c37f4a04ef89e73a39a59f3c5a179af8c8ab5974 
1package org.bouncycastle.asn1;
2
3import java.io.IOException;
4import java.math.BigInteger;
5
6import org.bouncycastle.util.Arrays;
7
8public class DERInteger
9    extends ASN1Object
10{
11    byte[]      bytes;
12
13    /**
14     * return an integer from the passed in object
15     *
16     * @exception IllegalArgumentException if the object cannot be converted.
17     */
18    public static DERInteger getInstance(
19        Object  obj)
20    {
21        if (obj == null || obj instanceof DERInteger)
22        {
23            return (DERInteger)obj;
24        }
25
26        if (obj instanceof ASN1OctetString)
27        {
28            return new DERInteger(((ASN1OctetString)obj).getOctets());
29        }
30
31        if (obj instanceof ASN1TaggedObject)
32        {
33            return getInstance(((ASN1TaggedObject)obj).getObject());
34        }
35
36        throw new IllegalArgumentException("illegal object in getInstance: " + obj.getClass().getName());
37    }
38
39    /**
40     * return an Integer from a tagged object.
41     *
42     * @param obj the tagged object holding the object we want
43     * @param explicit true if the object is meant to be explicitly
44     *              tagged false otherwise.
45     * @exception IllegalArgumentException if the tagged object cannot
46     *               be converted.
47     */
48    public static DERInteger getInstance(
49        ASN1TaggedObject obj,
50        boolean          explicit)
51    {
52        return getInstance(obj.getObject());
53    }
54
55    public DERInteger(
56        int         value)
57    {
58        bytes = BigInteger.valueOf(value).toByteArray();
59    }
60
61    public DERInteger(
62        BigInteger   value)
63    {
64        bytes = value.toByteArray();
65    }
66
67    public DERInteger(
68        byte[]   bytes)
69    {
70        this.bytes = bytes;
71    }
72
73    public BigInteger getValue()
74    {
75        return new BigInteger(bytes);
76    }
77
78    /**
79     * in some cases positive values get crammed into a space,
80     * that's not quite big enough...
81     */
82    public BigInteger getPositiveValue()
83    {
84        return new BigInteger(1, bytes);
85    }
86
87    void encode(
88        DEROutputStream out)
89        throws IOException
90    {
91        out.writeEncoded(INTEGER, bytes);
92    }
93
94    public int hashCode()
95    {
96         int     value = 0;
97
98         for (int i = 0; i != bytes.length; i++)
99         {
100             value ^= (bytes[i] & 0xff) << (i % 4);
101         }
102
103         return value;
104    }
105
106    boolean asn1Equals(
107        DERObject  o)
108    {
109        if (!(o instanceof DERInteger))
110        {
111            return false;
112        }
113
114        DERInteger other = (DERInteger)o;
115
116        return Arrays.areEqual(bytes, other.bytes);
117    }
118
119    public String toString()
120    {
121      return getValue().toString();
122    }
123}
124