/// <summary>
/// Helper function that turns the list of records into a DataTable, based on a decoding function that turns the raw byte data into a String.
/// </summary>
/// <param name="decodeBytes">Function to decode an array of bytes to a string.</param>
/// <param name="decodeField">Function to choose a C# .Net type for a DataColumn, based on a Starling field type.</param>
/// <returns>DataTable populated with the database's data.</returns>
private DataTable getDataTable(Func <byte[], String> decodeBytes, Func <StarlingDbfField.FieldType, Type> decodeField)
{
DataTable dt = new DataTable(table_name, "ns-" + table_name);
// add a column for the deleted marker and populate it
dt.Columns.Add("deleted", typeof(bool));
foreach (StarlingDbfRecord rec in records)
{
dt.Rows.Add(rec.record_status == StarlingDbfRecord.status.deleted);
}
// add other columns
int cell = 0;
for (int index_field = 0; index_field < header.field_structures.Count; index_field++)
{
// add column
StarlingDbfField fld = header.field_structures[index_field];
Type coltype = decodeField(fld.type);
DataColumn dc = new DataColumn(fld.name, coltype);
dt.Columns.Add(dc);
// populate column
for (int index_rec = 0; index_rec < records.Count; index_rec++)
{
// get database data as string
String s = decodeBytes(records[index_rec].field_contents[index_field]).Trim();
// add cell, with the data in the appropriate type
dt.Rows[index_rec].SetField(dc, decodedDataToType(s, coltype));
// report decoding difficulties/progress
if (s.Contains(StarlingDecoder.fallbackCharacter.ToString()))
{
Trace.WriteLine(String.Format("Check record {0}, field {1}.", index_rec + 1, index_field + 2));
}
reportProgress((100d * ++cell) / (records.Count * header.field_structures.Count), "Decoding");
}
}
return(dt);
}
/// <summary>
/// Constructor method that opens and reads a Starling database (.dbf).
/// </summary>
/// <param name="dbfFilename">Filename of the Starling database to be read.</param>
/// <param name="progressHandler">Optional event handler for progress reports.</param>
public StarlingDbfReader(String dbfFilename, ReportProgressEventHandler progressHandler = null)
{
// register optional event
if (progressHandler != null)
{
onProgressChanged += progressHandler;
}
// get var filename
String VarFilename = Path.ChangeExtension(dbfFilename, "var");
table_name = Path.GetFileNameWithoutExtension(dbfFilename);
if (File.Exists(dbfFilename))
{
// read header with database structure
reportProgress(0, "Reading header");
header = new StarlingDbfHeader(dbfFilename);
reportProgress(10, "Reading header: fields");
// log header info
Trace.WriteLine(dbfFilename);
Trace.WriteLine(String.Format("DBF Filesize:\t\t{0}", header.getFileSize()));
Trace.WriteLine(String.Format("Actual filesize:\t{0}", new FileInfo(dbfFilename).Length));
Trace.WriteLine("Header");
Trace.Indent();
foreach (String s in header.ToString().Split('\n'))
{
Trace.WriteLine(s);
}
Trace.Unindent();
Trace.WriteLine(String.Format("Fields ({0})", header.field_structures.Count));
Trace.Indent();
// read field structures
for (int i = 0; i < header.field_structures.Count; i++)
{
StarlingDbfField rec = header.field_structures[i];
// log field info
Trace.WriteLine(String.Format("Field {0}", i));
Trace.Indent();
foreach (String s in rec.ToString().Split('\n'))
{
Trace.WriteLine(s);
}
Trace.Unindent();
// report progress
reportProgress(10 + 10 * ((float)i / header.field_structures.Count), "Reading header: fields");
}
Trace.Unindent();
// read byte content for all records
reportProgress(20, "Reading records");
records = new List <StarlingDbfRecord>();
using (BinaryReader dbfFile = new BinaryReader(File.OpenRead(dbfFilename), Encoding.ASCII))
{
dbfFile.ReadBytes(header.HSZ);
while (dbfFile.BaseStream.Length - dbfFile.BaseStream.Position >= header.DRS)
{
StarlingDbfRecord rec = new StarlingDbfRecord(header, dbfFile.ReadBytes(header.DRS));
records.Add(rec);
reportProgress(20 + (40d * dbfFile.BaseStream.Position) / dbfFile.BaseStream.Length, "Reading records");
}
}
if (File.Exists(VarFilename))
{
// in case of an accompanying .var file, replace byte content of record fields if they are pointers to data in .var file
// first check if we are dealing with a .dbf file and if it contains data pointers
bool varfile_is_needed = false;
if (String.Equals(Path.GetExtension(dbfFilename), ".dbf", StringComparison.OrdinalIgnoreCase))
{
for (int i = 0; i < header.field_structures.Count && !varfile_is_needed; i++)
{
StarlingDbfField fld = header.field_structures[i];
varfile_is_needed = (fld.type == StarlingDbfField.FieldType.character && fld.fieldlength == 6);
}
}
if (varfile_is_needed)
{
reportProgress(60, "Processing records");
using (BinaryReader varFile = new BinaryReader(File.OpenRead(VarFilename), Encoding.ASCII))
{
// walk through all fields (columns)
for (int i = 0; i < header.field_structures.Count; i++)
{
// check if the field contains data pointers, if so update each record's contents
StarlingDbfField fld = header.field_structures[i];
if (fld.type == StarlingDbfField.FieldType.character && fld.fieldlength == 6)
{
/*
* We are dealing with a pointer to the VAR file here.
* The first 4 bytes give the position, the last 2 bytes give length.
*/
foreach (StarlingDbfRecord rec in records)
{
byte[] old_content = rec.field_contents[i];
if (!StarlingDbfRecord.emptyVarRef(old_content))
{
uint position = BitConverter.ToUInt32(old_content, 0);
ushort length = BitConverter.ToUInt16(old_content, 4);
varFile.BaseStream.Seek(position, SeekOrigin.Begin);
byte[] new_content = varFile.ReadBytes(length);
rec.field_contents[i] = new_content;
}
}
}
reportProgress(60 + (40d * i) / header.field_structures.Count, "Processing records");
}
}
}
}
reportProgress(100, "Database loaded");
// log records
//foreach (StarlingDbfRecord rec in records)
// Trace.WriteLine(rec.ToString());
}
else
{
Trace.WriteLine("DBF file not found.");
}
// unregister event
if (progressHandler != null)
{
onProgressChanged -= progressHandler;
}
}
