/// <summary> Constructs a Grib1BinaryDataSection object from a gribStream.
/// A bit map is defined.
///
/// </summary>
/// <param gridTemplateName="gribStream">gribStream with BDS content
/// </param>
/// <param gridTemplateName="decimalscale">the exponent of the decimal scale
/// </param>
/// <param gridTemplateName="bms">bit map numberOfSection of GRIB record
///
/// </param>
/// <throws> NotSupportedException if stream contains no valid GRIB file </throws>
//UPGRADE_TODO: Class 'java.io.RandomAccessFile' was converted to 'System.IO.FileStream' which has a different behavior. "ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?index='!DefaultContextWindowIndex'&keyword='jlca1073_javaioRandomAccessFile'"
public Grib1BinaryDataSection(System.IO.Stream raf, int decimalscale, Grib1BitMapSection bms)
{
// octets 1-3 (numberOfSection lengthOfSection)
length = (int)GribNumbers.uint3(raf);
//System.out.println( "BDS lengthOfSection = " + lengthOfSection );
// octet 4, 1st half (packing flag)
int unusedbits = raf.ReadByte();
// TODO Check this!!!
if ((unusedbits & 192) != 0)
throw new NGribCS.Helpers.GribNotSupportedException("BDS: (octet 4, 1st half) not grid point data and simple packing ");
// octet 4, 2nd half (number of unused bits at end of this numberOfSection)
unusedbits = unusedbits & 15;
//System.out.println( "BDS unusedbits = " + unusedbits );
// octets 5-6 (binary scale factor)
int binscale = GribNumbers.int2(raf);
// octets 7-10 (reference point = minimum value)
float refvalue = GribNumbers.float4(raf);
// octet 11 (number of bits per value)
int numbits = raf.ReadByte();
//System.out.println( "BDS numbits = " + numbits );
if (numbits == 0)
isConstant = true;
//System.out.println( "BDS isConstant = " + isConstant );
// *** read values *******************************************************
//UPGRADE_WARNING: Data types in Visual C# might be different. Verify the accuracy of narrowing conversions. "ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?index='!DefaultContextWindowIndex'&keyword='jlca1042'"
float ref_Renamed = (float) (System.Math.Pow(10.0, - decimalscale) * refvalue);
//UPGRADE_WARNING: Data types in Visual C# might be different. Verify the accuracy of narrowing conversions. "ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?index='!DefaultContextWindowIndex'&keyword='jlca1042'"
float scale = (float) (System.Math.Pow(10.0, - decimalscale) * System.Math.Pow(2.0, binscale));
if (bms != null)
{
bool[] bitmap = bms.Bitmap;
values = new float[bitmap.Length];
for (int i = 0; i < bitmap.Length; i++)
{
if (bitmap[i])
{
if (!isConstant)
{
values[i] = ref_Renamed + scale * bits2UInt(numbits, raf);
}
else
{
// rdg - added this to handle a constant valued parameter
values[i] = ref_Renamed;
}
}
else
values[i] = Grib1BinaryDataSection.UNDEFINED;
}
}
else
{
// bms is null
if (!isConstant)
{
//System.out.println( "BDS values.size = " +
//(((lengthOfSection - 11) * 8 - unusedbits) / numbits));
values = new float[((length - 11) * 8 - unusedbits) / numbits];
for (int i = 0; i < values.Length; i++)
{
values[i] = ref_Renamed + scale * bits2UInt(numbits, raf);
}
}
else
{
// constant valued - same min and max
int x = 0, y = 0;
raf.Seek(raf.Position - 53, System.IO.SeekOrigin.Begin); // return to start of GDS
length = (int)GribNumbers.uint3(raf);
if (length == 42)
{
// Lambert/Mercator offset
SupportClass.Skip(raf, 3);
x = GribNumbers.int2(raf);
y = GribNumbers.int2(raf);
}
else
{
SupportClass.Skip(raf, 7);
length = (int)GribNumbers.uint3(raf);
if (length == 32)
{
// Polar sterographic
SupportClass.Skip(raf, 3);
x = GribNumbers.int2(raf);
y = GribNumbers.int2(raf);
}
else
{
x = y = 1;
System.Console.Out.WriteLine("BDS constant value, can't determine array size");
}
}
values = new float[x * y];
for (int i = 0; i < values.Length; i++)
values[i] = ref_Renamed;
}
}
}
/// <summary> Reads the Grib data
///
/// </summary>
/// <param gridTemplateName="offset"> offset into file.
/// </param>
/// <param gridTemplateName="DecimalScale">
/// </param>
/// <param gridTemplateName="bmsExists">
/// </param>
/// <throws> NotSupportedException </throws>
/// <returns> float[]
/// </returns>
public float[] getData(long offset, int DecimalScale, bool bmsExists)
{
long start = (System.DateTime.Now.Ticks - 621355968000000000) / 10000;
raf.Seek(offset, System.IO.SeekOrigin.Begin);
//System.out.println( "gribStream.Position=" + gribStream.Position );
// Need numberOfSection 3 and 4 to read/interpet the data, numberOfSection 5
// as a check that all data read and sections are correct
Grib1BitMapSection bms = null;
if (bmsExists)
// read Bit Mapped Section 3
bms = new Grib1BitMapSection(raf);
// read Binary Data Section 4
Grib1BinaryDataSection bds = new Grib1BinaryDataSection(raf, DecimalScale, bms);
return bds.Values;
}
