/// <summary>
/// Initializes a new instance of the <see cref="DataElement"/> struct.
/// </summary>
/// <param name="class">The class.</param>
/// <param name="pc">The PC.</param>
/// <param name="tag">The tag.</param>
/// <param name="content">The content.</param>
public DataElement(BerClass @class, BerPC pc, BerTag tag, byte[] content)
: this()
{
this.Class = @class;
this.PC = pc;
this.Tag = tag;
this.Content = content;
}
public Ber(BerClass cl, BerTags tg, bool c)
{
allSet();
if ((int)cl > 3)
{
throw new Exception("class id must be from 0 to 3");
}
tagClass = (byte)((int)cl & 3);
_container = c;
_tag = (ulong)tg;
}
public Ber(BerClass cl, BerTags tg, bool c, byte[] pl)
{
allSet();
if ((int)cl > 3)
{
throw new Exception("class id must be from 0 to 3");
}
tagClass = (byte)((int)cl & 3);
_container = c;
_tag = (ulong)tg;
_payload = pl;
_payloadLength = pl.Length;
}
/// <summary>
/// Reads a sequence of ASN.1 elements from a stream.
/// </summary>
/// <param name="stream">The stream.</param>
/// <returns>A sequence of elements.</returns>
/// <remarks>
/// The stream may not contain exclusively ASN.1 data.
/// This method will read the stream exactly one element at a time,
/// and the caller should only enumerate as many elements as are expected
/// to avoid reading into other data.
/// If the end of the stream is reached, the sequence terminates.
/// </remarks>
internal static IEnumerable <DataElement> ReadAsn1Elements(this Stream stream)
{
Requires.NotNull(stream, "stream");
do
{
int b = stream.ReadByte();
if (b == -1)
{
yield break;
}
BerClass clazz = (BerClass)b & BerClass.Mask;
BerPC pc = (BerPC)b & BerPC.Mask;
BerTag tag = (BerTag)b & BerTag.Mask;
uint length = 0;
b = stream.ReadByte();
if ((b & 0x80) == 0x80)
{
// long form
byte lengthOfLength = (byte)(b & 0x7F);
for (int i = 0; i < lengthOfLength; i++)
{
// big endian
b = stream.ReadByte();
length <<= 8;
length += (uint)b;
}
}
else
{
// short form.
length = (uint)b;
}
if (length > 8 * 1024)
{
throw new FormatException("Invalid format or length too large.");
}
byte[] content = new byte[length];
int bytesRead = stream.Read(content, 0, (int)length);
if (bytesRead != length)
{
throw new ArgumentException("Unexpected end of stream.");
}
yield return(new DataElement(clazz, pc, tag, content));
}while (true);
}
/// <summary>
/// Reverses the operation GetShortClassName(), returning true
/// if <paramref name="name"/> could be parsed into a BerClass value.
/// </summary>
public static bool GetClassFromName(string name, bool ignoreCase, out BerClass tagClass)
{
var comparison = ignoreCase
? StringComparison.CurrentCultureIgnoreCase
: StringComparison.CurrentCulture;
for (int index = 0; index < ShortClassNames.Length; index++)
{
if (String.Compare(ShortClassNames[index], name, comparison) == 0)
{
tagClass = (BerClass)(index << 6);
return(true);
}
}
tagClass = BerClass.Universal;
return(false);
}
/// <summary>
/// Constructs a new BerTag instance.
/// </summary>
/// <param name="tagClass">The tag class.</param>
/// <param name="number">The tag number.</param>
/// <param name="isContainer">If true, the container flag is set.</param>
public BerTag(BerClass tagClass, uint number, bool isContainer)
: this(tagClass, number)
{
IsContainer = isContainer;
}
/// <summary>
/// Constructs a new BerTag instance, not setting
/// the container flag.
/// </summary>
/// <param name="tagClass">The tag class.</param>
/// <param name="number">The tag number.</param>
public BerTag(BerClass tagClass, uint number)
: this()
{
Preamble = (byte)(tagClass & BerClass.Mask);
Number = number;
}
/// <summary>
/// Initializes a new instance of the <see cref="DataElement"/> struct.
/// </summary>
/// <param name="class">The class.</param>
/// <param name="pc">The PC.</param>
/// <param name="tag">The tag.</param>
/// <param name="nestedElements">The content.</param>
public DataElement(BerClass @class, BerPC pc, BerTag tag, params DataElement[] nestedElements)
: this(@class, pc, tag, Asn.WriteAsn1Elements(nestedElements))
{
}
/// <summary>
/// Gets the name of the tag class identified by <paramref name="tagClass"/>:
/// either 'C' (context-specific), 'A' (application), 'U' (universal) or
/// 'P' (private).
/// </summary>
public static string GetShortClassName(BerClass tagClass)
{
return(ShortClassNames[(byte)tagClass >> 6]);
}
/// <summary>
/// Initializes a new instance of the <see cref="DataElement"/> struct.
/// </summary>
/// <param name="class">The class.</param>
/// <param name="pc">The PC.</param>
/// <param name="tag">The tag.</param>
/// <param name="nestedElements">The content.</param>
public DataElement(BerClass @class, BerPC pc, BerTag tag, params DataElement[] nestedElements)
: this(@class, pc, tag, Asn.WriteAsn1Elements(nestedElements))
{
}
/// <summary>
/// Initializes a new instance of the <see cref="DataElement"/> struct.
/// </summary>
/// <param name="class">The class.</param>
/// <param name="pc">The PC.</param>
/// <param name="tag">The tag.</param>
/// <param name="content">The content.</param>
public DataElement(BerClass @class, BerPC pc, BerTag tag, byte[] content)
: this()
{
this.Class = @class;
this.PC = pc;
this.Tag = tag;
this.Content = content;
}
/// <summary>
/// Gets the name of the tag class identified by <paramref name="tagClass"/>:
/// either 'C' (context-specific), 'A' (application), 'U' (universal) or
/// 'P' (private).
/// </summary>
public static string GetShortClassName(BerClass tagClass)
{
return ShortClassNames[(byte)tagClass >> 6];
}
/// <summary>
/// Reverses the operation GetShortClassName(), returning true
/// if <paramref name="name"/> could be parsed into a BerClass value.
/// </summary>
public static bool GetClassFromName(string name, bool ignoreCase, out BerClass tagClass)
{
var comparison = ignoreCase
? StringComparison.CurrentCultureIgnoreCase
: StringComparison.CurrentCulture;
for(int index = 0; index < ShortClassNames.Length; index++)
{
if(String.Compare(ShortClassNames[index], name, comparison) == 0)
{
tagClass = (BerClass)(index << 6);
return true;
}
}
tagClass = BerClass.Universal;
return false;
}
