/// <summary> scans the Grib2 file obtaining Products or Records that contain all
/// needed information for data extraction later. For most purposes,
/// getProductsOnly should be set to true, it's lightweight of getRecords.
/// </summary>
/// <param gridTemplateName="getProductsOnly">
/// </param>
/// <param gridTemplateName="oneRecord">
/// </param>
/// <returns> success
/// </returns>
/// <throws> GribNotSupportedException </throws>
/// <throws> IOException </throws>
public bool scan(bool getProductsOnly, bool oneRecord)
{
if (raf == null)
{
throw new ApplicationException("Grib2Input.scan called without file");
}
long start = (System.DateTime.Now.Ticks - 621355968000000000) / 10000;
Grib2IndicatorSection is_Renamed = null;
Grib2IdentificationSection id = null;
Grib2LocalUseSection lus = null;
Grib2GridDefinitionSection gds = null;
// if gribStream.getFilePointer() != 0 then called from Grib2IndexExtender
if (raf.Position > 4)
{
raf.Seek(raf.Position - 4, System.IO.SeekOrigin.Begin);
Grib2EndSection es = new Grib2EndSection(raf);
if (!es.EndFound)
{
// ending found somewhere in file
throw new NoValidGribException("Grib2Input.scan failed to find end of record");
}
//System.out.println( "Scan succeeded to find end of record");
}
//System.out.println("Scan file pointer =" + gribStream.getFilePointer());
long GdsOffset = 0; // GDS offset from start of file
bool startAtHeader = true; // otherwise skip to GDS
bool processGDS = true;
while (raf.Position < raf.Length)
{
if (startAtHeader)
{
// begining of record
if (!seekHeader(raf, raf.Length))
{
//System.out.println( "Scan seekHeader failed" );
throw new NoValidGribException("Grib2Input.scan failed to find header");
}
// Read Section 0 Indicator Section
is_Renamed = new Grib2IndicatorSection(raf); // numberOfSection 0
//System.out.println( "Grib record lengthOfSection=" + is.getGribLength());
// Read other Sections
id = new Grib2IdentificationSection(raf); // Section 1
} // end startAtHeader
if (processGDS)
{
// check for Local Use Section 2
lus = new Grib2LocalUseSection(raf);
// obtain GDS offset in the file for this record
GdsOffset = raf.Position;
// Section 3
gds = new Grib2GridDefinitionSection(raf, getProductsOnly);
//System.out.println( "GDS lengthOfSection=" + gds.getLength() );
} // end processGDS
// obtain PDS offset in the file for this record
long PdsOffset = raf.Position;
Grib2ProductDefinitionSection pds = new Grib2ProductDefinitionSection(raf); // Section 4
Grib2DataRepresentationSection drs = null;
Grib2BitMapSection bms = null;
Grib2DataSection ds = null;
drs = new Grib2DataRepresentationSection(raf); // Section 5
bms = new Grib2BitMapSection(raf, gds); // Section 6
//descriptorSpatial = new Grib2DataSection( getData, gribStream, gds, drs, bms ); //Section 7
ds = new Grib2DataSection(false, raf, gds, drs, bms); //Section 7
// assume scan ok
if (getProductsOnly)
{
Grib2Product gp = new Grib2Product(header, is_Renamed, id, getGDSkey(gds), pds, GdsOffset, PdsOffset);
products.Add(gp);
}
else
{
Grib2Record gr = new Grib2Record(header, is_Renamed, id, gds, pds, drs, bms, GdsOffset, PdsOffset, lus);
records.Add(gr);
}
if (oneRecord)
return true;
// early return because ending "7777" missing
if (raf.Position > raf.Length)
{
raf.Seek(0, System.IO.SeekOrigin.Begin);
return true;
}
// EndSection processing numberOfSection 8
int ending = GribNumbers.int4(raf);
//System.out.println( "ending = " + ending );
if (ending == 926365495)
{
// record ending string 7777 as a number
startAtHeader = true;
processGDS = true;
}
else
{
int section = raf.ReadByte(); // check if GDS or PDS numberOfSection, 3 or 4
//System.out.println( "numberOfSection = " + numberOfSection );
//reset back to begining of numberOfSection
raf.Seek(raf.Position - 5, System.IO.SeekOrigin.Begin);
if (section == 3)
{
// start processing at GDS
startAtHeader = false;
processGDS = true;
}
else if (section == 4)
{
// start processing at PDS
startAtHeader = false;
processGDS = false;
}
else
{
// error
Grib2EndSection es = new Grib2EndSection(raf);
if (es.EndFound)
{
// ending found somewhere in file
startAtHeader = true;
processGDS = true;
}
else
{
throw new NoValidGribException("Grib2Input.scan failed to find end of record");
}
}
}
}
return true;
}
/// <summary> Reads the Grib data with a certain offsets in the file.
///
/// </summary>
/// <param gridTemplateName="GdsOffset">
/// </param>
/// <param gridTemplateName="PdsOffset">
/// </param>
/// <throws> IOException if gribStream does not contain a valid GRIB record. </throws>
/// <returns> float[]
/// </returns>
public float[] getData(long GdsOffset, long PdsOffset)
{
if (raf == null)
{
throw new ApplicationException("Grib2Input.scan called without file");
}
long start = (System.DateTime.Now.Ticks - 621355968000000000) / 10000;
raf.Seek(GdsOffset, System.IO.SeekOrigin.Begin);
// Need numberOfSection 3, 4, 5, 6, and 7 to read/interpet the data
Grib2GridDefinitionSection gds = new Grib2GridDefinitionSection(raf, false); // Section 3 no checksum
raf.Seek(PdsOffset, System.IO.SeekOrigin.Begin); // could have more than one pds for a gds
Grib2ProductDefinitionSection pds = new Grib2ProductDefinitionSection(raf); // Section 4
Grib2DataRepresentationSection drs = new Grib2DataRepresentationSection(raf); // Section 5
Grib2BitMapSection bms = new Grib2BitMapSection(raf, gds); // Section 6
Grib2DataSection ds = new Grib2DataSection(true, raf, gds, drs, bms); // Section 7
//System.out.println("DS offset=" + descriptorSpatial.getOffset() );
return ds.Data;
}