/// <summary>
/// Generates a <c>SECSItem</c> from data in "wire/transmission" format.
/// </summary>
/// <returns>The resulting <c>SECSItem</c>.</returns>
/// <param name="data">An array of bytes that is in wire/transmission format.</param>
/// <param name="offset">The byte offset into <c>data</c> where the data for
/// a <c>SECSITEM</c> starts.</param>
public static SECSItem GenerateSECSItem(byte[] data, int offset)
{
SECSItem result = null;
SECSItemFormatCode formatCode = SECSItemFormatCodeFunctions.GetSECSItemFormatCodeFromNumber((byte)((data[offset] >> 2) & 0x0000003F));
int numberOfLengthBytes = (data[offset] & 0x03);
int incomingDataLength = 0;
switch (numberOfLengthBytes)
{
case 1:
{
byte[] temp = new byte[4];
temp[0] = 0;
temp[1] = 0;
temp[2] = 0;
temp[3] = data[offset + 1];
if (BitConverter.IsLittleEndian)
{
Array.Reverse(temp);
}
incomingDataLength = BitConverter.ToInt32(temp, 0);
break;
}
case 2:
{
byte[] temp = new byte[4];
temp[0] = 0;
temp[1] = 0;
temp[2] = data[offset + 1];
temp[3] = data[offset + 2];
if (BitConverter.IsLittleEndian)
{
Array.Reverse(temp);
}
incomingDataLength = BitConverter.ToInt32(temp, 0);
break;
}
case 3:
{
byte[] temp = new byte[4];
temp[0] = 0;
temp[1] = data[offset + 1];
temp[2] = data[offset + 2];
temp[3] = data[offset + 3];
if (BitConverter.IsLittleEndian)
{
Array.Reverse(temp);
}
incomingDataLength = BitConverter.ToInt32(temp, 0);
break;
}
}
switch (formatCode)
{
case SECSItemFormatCode.L:
result = new ListSECSItem(data, offset);
break;
case SECSItemFormatCode.B:
result = new BinarySECSItem(data, offset);
break;
case SECSItemFormatCode.BO:
if (incomingDataLength == 1)
{
result = new BooleanSECSItem(data, offset);
}
else
{
result = new BooleanArraySECSItem(data, offset);
}
break;
case SECSItemFormatCode.A:
result = new ASCIISECSItem(data, offset);
break;
case SECSItemFormatCode.J8:
break;
case SECSItemFormatCode.C2:
break;
case SECSItemFormatCode.I8:
if (incomingDataLength == 8)
{
result = new I8SECSItem(data, offset);
}
else
{
result = new I8ArraySECSItem(data, offset);
}
break;
case SECSItemFormatCode.I1:
if (incomingDataLength == 1)
{
result = new I1SECSItem(data, offset);
}
else
{
result = new I1ArraySECSItem(data, offset, 0); // Need to use this version because of method signature issues
}
break;
case SECSItemFormatCode.I2:
if (incomingDataLength == 2)
{
result = new I2SECSItem(data, offset);
}
else
{
result = new I2ArraySECSItem(data, offset);
}
break;
case SECSItemFormatCode.I4:
if (incomingDataLength == 4)
{
result = new I4SECSItem(data, offset);
}
else
{
result = new I4ArraySECSItem(data, offset);
}
break;
case SECSItemFormatCode.F8:
if (incomingDataLength == 8)
{
result = new F8SECSItem(data, offset);
}
else
{
result = new F8ArraySECSItem(data, offset);
}
break;
case SECSItemFormatCode.F4:
if (incomingDataLength == 4)
{
result = new F4SECSItem(data, offset);
}
else
{
result = new F4ArraySECSItem(data, offset);
}
break;
case SECSItemFormatCode.U8:
if (incomingDataLength == 8)
{
result = new U8SECSItem(data, offset);
}
else
{
result = new U8ArraySECSItem(data, offset);
}
break;
case SECSItemFormatCode.U1:
if (incomingDataLength == 1)
{
result = new U1SECSItem(data, offset);
}
else
{
result = new U1ArraySECSItem(data, offset, 0); // Remember to use the proper constructor for this case
}
break;
case SECSItemFormatCode.U2:
if (incomingDataLength == 2)
{
result = new U2SECSItem(data, offset);
}
else
{
result = new U2ArraySECSItem(data, offset);
}
break;
case SECSItemFormatCode.U4:
if (incomingDataLength == 4)
{
result = new U4SECSItem(data, offset);
}
else
{
result = new U4ArraySECSItem(data, offset);
}
break;
case SECSItemFormatCode.UNDEFINED:
break;
case SECSItemFormatCode.HeaderOnly:
break;
default:
break;
}
return(result);
}
/// <summary>
/// This is a base class constructor for a SECSItem. This form of the constructor
/// is used when parsing wire/transmission format data and converting it into
/// its "C# form".
///
/// This constructor sets the following base class attributes from the provided data:
/// <c>formatCode</c>,
/// <c>inboundNumberOfLengthBytes</c>,
/// <c>outboundNumberOfLengthBytes</c>
/// <c>lengthInBytes</c> or if the <c>formatCode</c> is of type <c>L</c>(List) <c>lengthInBytes</c>
/// will be the number of items in the list.
///
/// The exception <c>ArgumentException</c> will be thrown in the following circumstances:
/// the <c>data</c> argument is <c>null</c>, the <c>data</c> argument has a length of zero, or
/// the number of length bytes parsed out is zero.
///
/// In normal use the only time the <c>ArgumentException</c>
/// exception should be caught is if you are reading data from a piece of
/// equipment that does not properly speak SECS and you want to be able to
/// recover from the error gracefully.Typically the ACM process will have
/// detected this equipment and it will not be allowed into the factory in
/// the first place.
/// </summary>
protected SECSItem(byte[] data, int itemOffset)
{
if (data == null)
{
throw new ArgumentNullException("\"data\" argument must not be null.");
}
if (data.Length < 2)
{
throw new ArgumentException("\"data\" argument must have a length >= 2.");
}
/*
* if (data.Length == 0)
* {
* throw new ArgumentException ("The number of length bytes is not allowed to be ZERO.");
* }
*/
formatCode = SECSItemFormatCodeFunctions.GetSECSItemFormatCodeFromNumber((byte)((data[itemOffset] >> 2) & 0x0000003F));
byte[] temp1 = new byte[4];
switch (data [itemOffset] & 0x03)
{
case 0:
{
throw new ArgumentException("The number of length bytes is not allowed to be ZERO.");
}
case 1:
{
inboundNumberOfLengthBytes = SECSItemNumLengthBytes.ONE;
outboundNumberOfLengthBytes = inboundNumberOfLengthBytes;
temp1[0] = 0;
temp1[1] = 0;
temp1[2] = 0;
temp1[3] = data[itemOffset + 1];
break;
}
case 2:
{
inboundNumberOfLengthBytes = SECSItemNumLengthBytes.TWO;
outboundNumberOfLengthBytes = inboundNumberOfLengthBytes;
if (data.Length < 3)
{
throw new ArgumentException("With two length bytes the minimum length for the \"data\" argument is 3.");
}
temp1[0] = 0;
temp1[1] = 0;
temp1[2] = data[itemOffset + 1];
temp1[3] = data[itemOffset + 2];
break;
}
case 3:
{
inboundNumberOfLengthBytes = SECSItemNumLengthBytes.THREE;
outboundNumberOfLengthBytes = inboundNumberOfLengthBytes;
if (data.Length < 4)
{
throw new ArgumentException("With three length bytes the minimum length for the \"data\" argument is 4.");
}
temp1[0] = 0;
temp1[1] = data[itemOffset + 1];
temp1[2] = data[itemOffset + 2];
temp1[3] = data[itemOffset + 3];
break;
}
}
if (BitConverter.IsLittleEndian)
{
Array.Reverse(temp1);
}
lengthInBytes = BitConverter.ToInt32(temp1, 0);
/*
* if (formatCode == SECSItemFormatCode.L)
* numberOfElements = incomingDataLength;
* else
* lengthInBytes = incomingDataLength;
*/
}