/// <summary>
/// Add the content of the given writer to the writer
/// </summary>
/// <param name="writer"></param>
/// <remarks>
/// This functionality is not allowed when the writer has been sealed
/// </remarks>
public void WriteBytes(ByteArrayWriter writer)
{
this.WriteBytes(
writer._buffer,
0,
writer._length);
}
/// <summary>
/// Parse a string containing an HEX representation to a byte-array
/// </summary>
/// <param name="source">The source string containing HEX characters.</param>
/// <returns>The resulting byte-array</returns>
/// <remarks>
/// <para>The conversion does not care about character casing.</para>
/// <para>Any character off the HEX-set is treated as separator.</para>
/// <para>The HEX-chars can be even without any separator (i.e. packed),
/// however the conversion consider character pairs.</para>
/// </remarks>
/// <example>Sample behavior of the conversion:
/// <code>
/// byte[] b = ByteArrayHelpers.FromHex("0 zz@ q1 23 04 567 8! 9 abcdef");
///
/// for (int i = 0; i < b.Length; i++)
/// {
/// Console.Write(b[i].ToString() + " ");
/// }
/// Console.WriteLine();
///
/// </code>
/// Yields the result:
/// <code>
/// 0 1 35 4 86 7 8 9 171 205 239
/// </code>
/// </example>
/// <seealso cref="ToHex"/>
public static byte[] FromHex(string source)
{
if (_tblfromhex == null)
{
InitFromHexConverter();
}
//create a string reader to consume input chars
var reader = new SimpleStringReader(source);
//create a writer to accumulate the resulting bytes
var writer = new ByteArrayWriter();
//consume characters until the end of string
int nibble = 0;
int digit = 0;
int code;
while ((code = reader.GetNext()) >= 0)
{
if (code > 0)
{
digit = (digit << 8) | (code - 1);
nibble++;
}
else if (nibble > 0)
{
nibble = 2;
}
if (nibble == 2)
{
writer.WriteByte((byte)digit);
digit = 0;
nibble = 0;
}
}
return(writer.ToByteArray());
}
