kopia lustrzana https://github.com/dl2alf/AirScout
369 wiersze
11 KiB
C#
369 wiersze
11 KiB
C#
using System;
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using System.Diagnostics;
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using System.IO;
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using System.Text;
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using Org.BouncyCastle.Math;
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using Org.BouncyCastle.Utilities;
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namespace Org.BouncyCastle.Asn1
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{
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public class DerBitString
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: DerStringBase, Asn1BitStringParser
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{
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internal class Meta : Asn1UniversalType
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{
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internal static readonly Asn1UniversalType Instance = new Meta();
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private Meta() : base(typeof(DerBitString), Asn1Tags.BitString) { }
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internal override Asn1Object FromImplicitPrimitive(DerOctetString octetString)
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{
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return CreatePrimitive(octetString.GetOctets());
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}
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internal override Asn1Object FromImplicitConstructed(Asn1Sequence sequence)
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{
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return sequence.ToAsn1BitString();
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}
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}
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private static readonly char[] table
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= { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F' };
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/**
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* return a Bit string from the passed in object
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*
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* @exception ArgumentException if the object cannot be converted.
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*/
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public static DerBitString GetInstance(object obj)
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{
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if (obj == null || obj is DerBitString)
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{
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return (DerBitString)obj;
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}
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//else if (obj is Asn1BitStringParser)
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else if (obj is IAsn1Convertible)
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{
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Asn1Object asn1Object = ((IAsn1Convertible)obj).ToAsn1Object();
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if (asn1Object is DerBitString)
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return (DerBitString)asn1Object;
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}
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else if (obj is byte[])
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{
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try
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{
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return GetInstance(FromByteArray((byte[])obj));
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}
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catch (IOException e)
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{
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throw new ArgumentException("failed to construct BIT STRING from byte[]: " + e.Message);
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}
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}
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throw new ArgumentException("illegal object in GetInstance: " + Platform.GetTypeName(obj));
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}
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/**
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* return a Bit string from a tagged object.
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*
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* @param obj the tagged object holding the object we want
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* @param explicitly true if the object is meant to be explicitly
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* tagged false otherwise.
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* @exception ArgumentException if the tagged object cannot
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* be converted.
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*/
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public static DerBitString GetInstance(Asn1TaggedObject obj, bool isExplicit)
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{
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Asn1Object o = obj.GetObject();
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if (isExplicit || o is DerBitString)
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{
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return GetInstance(o);
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}
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// Not copied because assumed to be a tagged implicit primitive from the parser
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return CreatePrimitive(((Asn1OctetString)o).GetOctets());
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}
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internal readonly byte[] contents;
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public DerBitString(byte data, int padBits)
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{
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if (padBits > 7 || padBits < 0)
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throw new ArgumentException("pad bits cannot be greater than 7 or less than 0", "padBits");
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this.contents = new byte[] { (byte)padBits, data };
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}
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public DerBitString(byte[] data)
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: this(data, 0)
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{
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}
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/**
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* @param data the octets making up the bit string.
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* @param padBits the number of extra bits at the end of the string.
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*/
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public DerBitString(byte[] data, int padBits)
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{
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if (data == null)
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throw new ArgumentNullException("data");
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if (padBits < 0 || padBits > 7)
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throw new ArgumentException("must be in the range 0 to 7", "padBits");
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if (data.Length == 0 && padBits != 0)
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throw new ArgumentException("if 'data' is empty, 'padBits' must be 0");
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this.contents = Arrays.Prepend(data, (byte)padBits);
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}
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public DerBitString(int namedBits)
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{
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if (namedBits == 0)
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{
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this.contents = new byte[]{ 0 };
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return;
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}
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int bits = BigInteger.BitLen(namedBits);
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int bytes = (bits + 7) / 8;
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Debug.Assert(0 < bytes && bytes <= 4);
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byte[] data = new byte[1 + bytes];
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for (int i = 1; i < bytes; i++)
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{
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data[i] = (byte)namedBits;
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namedBits >>= 8;
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}
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Debug.Assert((namedBits & 0xFF) != 0);
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data[bytes] = (byte)namedBits;
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int padBits = 0;
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while ((namedBits & (1 << padBits)) == 0)
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{
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++padBits;
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}
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Debug.Assert(padBits < 8);
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data[0] = (byte)padBits;
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this.contents = data;
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}
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public DerBitString(Asn1Encodable obj)
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: this(obj.GetDerEncoded())
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{
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}
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internal DerBitString(byte[] contents, bool check)
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{
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if (check)
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{
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if (null == contents)
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throw new ArgumentNullException("contents");
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if (contents.Length < 1)
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throw new ArgumentException("cannot be empty", "contents");
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int padBits = contents[0];
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if (padBits > 0)
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{
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if (contents.Length < 2)
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throw new ArgumentException("zero length data with non-zero pad bits", "contents");
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if (padBits > 7)
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throw new ArgumentException("pad bits cannot be greater than 7 or less than 0", "contents");
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}
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}
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this.contents = contents;
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}
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/**
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* Return the octets contained in this BIT STRING, checking that this BIT STRING really
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* does represent an octet aligned string. Only use this method when the standard you are
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* following dictates that the BIT STRING will be octet aligned.
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*
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* @return a copy of the octet aligned data.
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*/
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public virtual byte[] GetOctets()
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{
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if (contents[0] != 0)
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throw new InvalidOperationException("attempt to get non-octet aligned data from BIT STRING");
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return Arrays.CopyOfRange(contents, 1, contents.Length);
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}
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public virtual byte[] GetBytes()
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{
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if (contents.Length == 1)
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return Asn1OctetString.EmptyOctets;
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int padBits = contents[0];
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byte[] rv = Arrays.CopyOfRange(contents, 1, contents.Length);
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// DER requires pad bits be zero
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rv[rv.Length - 1] &= (byte)(0xFF << padBits);
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return rv;
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}
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public virtual int PadBits
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{
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get { return contents[0]; }
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}
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/**
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* @return the value of the bit string as an int (truncating if necessary)
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*/
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public virtual int IntValue
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{
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get
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{
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int value = 0, end = System.Math.Min(5, contents.Length - 1);
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for (int i = 1; i < end; ++i)
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{
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value |= (int)contents[i] << (8 * (i - 1));
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}
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if (1 <= end && end < 5)
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{
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int padBits = contents[0];
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byte der = (byte)(contents[end] & (0xFF << padBits));
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value |= (int)der << (8 * (end - 1));
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}
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return value;
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}
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}
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internal override IAsn1Encoding GetEncoding(int encoding)
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{
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int padBits = contents[0];
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if (padBits != 0)
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{
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int last = contents.Length - 1;
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byte lastBer = contents[last];
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byte lastDer = (byte)(lastBer & (0xFF << padBits));
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if (lastBer != lastDer)
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return new PrimitiveEncodingSuffixed(Asn1Tags.Universal, Asn1Tags.BitString, contents, lastDer);
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}
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return new PrimitiveEncoding(Asn1Tags.Universal, Asn1Tags.BitString, contents);
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}
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internal override IAsn1Encoding GetEncodingImplicit(int encoding, int tagClass, int tagNo)
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{
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int padBits = contents[0];
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if (padBits != 0)
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{
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int last = contents.Length - 1;
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byte lastBer = contents[last];
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byte lastDer = (byte)(lastBer & (0xFF << padBits));
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if (lastBer != lastDer)
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return new PrimitiveEncodingSuffixed(tagClass, tagNo, contents, lastDer);
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}
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return new PrimitiveEncoding(tagClass, tagNo, contents);
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}
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protected override int Asn1GetHashCode()
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{
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if (contents.Length < 2)
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return 1;
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int padBits = contents[0];
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int last = contents.Length - 1;
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byte lastDer = (byte)(contents[last] & (0xFF << padBits));
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int hc = Arrays.GetHashCode(contents, 0, last);
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hc *= 257;
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hc ^= lastDer;
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return hc;
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}
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protected override bool Asn1Equals(Asn1Object asn1Object)
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{
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DerBitString that = asn1Object as DerBitString;
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if (null == that)
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return false;
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byte[] thisContents = this.contents, thatContents = that.contents;
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int length = thisContents.Length;
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if (thatContents.Length != length)
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return false;
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if (length == 1)
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return true;
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int last = length - 1;
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for (int i = 0; i < last; ++i)
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{
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if (thisContents[i] != thatContents[i])
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return false;
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}
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int padBits = thisContents[0];
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byte thisLastDer = (byte)(thisContents[last] & (0xFF << padBits));
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byte thatLastDer = (byte)(thatContents[last] & (0xFF << padBits));
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return thisLastDer == thatLastDer;
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}
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public Stream GetBitStream()
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{
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return new MemoryStream(contents, 1, contents.Length - 1, false);
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}
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public Stream GetOctetStream()
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{
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int padBits = contents[0] & 0xFF;
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if (0 != padBits)
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throw new IOException("expected octet-aligned bitstring, but found padBits: " + padBits);
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return GetBitStream();
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}
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public Asn1BitStringParser Parser
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{
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get { return this; }
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}
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public override string GetString()
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{
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byte[] str = GetDerEncoded();
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StringBuilder buffer = new StringBuilder(1 + str.Length * 2);
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buffer.Append('#');
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for (int i = 0; i != str.Length; i++)
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{
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uint u8 = str[i];
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buffer.Append(table[u8 >> 4]);
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buffer.Append(table[u8 & 0xF]);
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}
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return buffer.ToString();
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}
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internal static DerBitString CreatePrimitive(byte[] contents)
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{
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int length = contents.Length;
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if (length < 1)
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throw new ArgumentException("truncated BIT STRING detected", "contents");
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int padBits = contents[0];
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if (padBits > 0)
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{
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if (padBits > 7 || length < 2)
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throw new ArgumentException("invalid pad bits detected", "contents");
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byte finalOctet = contents[length - 1];
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if (finalOctet != (byte)(finalOctet & (0xFF << padBits)))
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return new DLBitString(contents, false);
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}
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return new DerBitString(contents, false);
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}
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}
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}
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