/// <summary>
/// Read a single row from the dBase file
/// </summary>
/// <param name="header">DBase File header</param>
/// <param name="reader">BinaryReader that stream is being read from</param>
/// <param name="colRules">List of column indices to skip</param>
/// <param name="numValidRulesCols">Number of columns that are marked true in the column rules array</param>
/// <returns>A Dictionary of objects</returns>
internal static Dictionary <string, object> ReadRow(DBaseFileHeader header, BinaryReader reader, bool[] colRules, int numValidRulesCols)
{
Dictionary <string, object> row = null;
bool foundRow = false;
//loop through until there are no more valid rows
while (!foundRow)
{
//Initialize DBaseRow
row = new Dictionary <string, object>();
//Read the deleted flag
char deletedFlag = (char)reader.ReadChar();
//Read the row length
int rowLength = 1; // for the deleted character just read.
char[] buffer; //a reusable character array used for holding characters
string tempString; //a resuable variable for string a string
object cellObject;
//Read the rows
for (int j = 0; j < header.NumColumns; j++)
{
//Get the cell length
int cellLength = header.ColumnDescriptions[j].Length;
rowLength = rowLength + cellLength;
// read the data.
cellObject = null;
if (colRules == null || colRules[j])
{
//Switch on the DBaseType of the cell
switch (header.ColumnDescriptions[j].DBaseType)
{
case 'L': //boolean
char tempChar = (char)reader.ReadByte();
// Check DBase boolean characters (T,t,F,f,Y,y,N,n)
if (char.ToUpper(tempChar) == 'T' || char.ToUpper(tempChar) == 'Y')
{
cellObject = true;
}
else
{
cellObject = false;
}
break;
case 'C': //String or character
buffer = new char[cellLength];
buffer = reader.ReadChars(cellLength);
//Trim whitespaces and remove any \0 values
cellObject = new string(buffer).Trim().Replace("\0", String.Empty);
break;
case 'D': //Date YYYYMMDD
buffer = new char[8];
buffer = reader.ReadChars(8);
//Parse the date parameters out of the character array
int year = Int32.Parse(new string(buffer, 0, 4), CultureInfo.InvariantCulture);
int month = Int32.Parse(new string(buffer, 4, 2), CultureInfo.InvariantCulture);
int day = Int32.Parse(new string(buffer, 6, 2), CultureInfo.InvariantCulture);
//create a DateTime object
cellObject = new DateTime(year, month, day);
break;
case 'I': //Integer
buffer = new char[cellLength];
buffer = reader.ReadChars(cellLength);
tempString = new string(buffer).Trim();
int intNumber;
//Try and parse the integer
if (int.TryParse(tempString, NumberStyles.Integer, CultureInfo.InvariantCulture, out intNumber))
{
cellObject = intNumber;
}
break;
case 'N': //Double
buffer = new char[cellLength];
buffer = reader.ReadChars(cellLength);
tempString = new string(buffer).Trim();
double doubleNumber;
//Try and parse the double
if (double.TryParse(tempString, NumberStyles.AllowDecimalPoint, CultureInfo.InvariantCulture, out doubleNumber))
{
cellObject = doubleNumber;
}
break;
case 'F': //float
buffer = new char[cellLength];
buffer = reader.ReadChars(cellLength);
tempString = new string(buffer).Trim();
float floatNumber;
//Try and parse the float
if (float.TryParse(tempString, NumberStyles.AllowDecimalPoint, CultureInfo.InvariantCulture, out floatNumber))
{
cellObject = floatNumber;
}
break;
default:
break;
}
//Add the cell object to the row
row.Add(header.ColumnDescriptions[j].Name, cellObject);
}
else
{
reader.BaseStream.Seek(cellLength, SeekOrigin.Current);
}
}
//Check to see if the full row has been read.
if (rowLength < header.RowLength)
{
//Skip to the end of the row
reader.BaseStream.Seek(header.RowLength - rowLength, SeekOrigin.Current);
}
//Add the row if it is not deleted.
if (deletedFlag != '*')
{
foundRow = true;
}
}
return(row);
}
/// <summary>
/// Reads the header data from a DBF file using a BinarayReader
/// </summary>
/// <param name="reader">BinaryReader containing the DBF file</param>
/// <returns>A DBaseFileHeader object with the header information of the DBF file</returns>
public static DBaseFileHeader ReadHeader(BinaryReader reader)
{
//initialize the dBase Header object
DBaseFileHeader header = new DBaseFileHeader();
//The first byte in the reader should be the file type. Verify that this is correct.
if (reader.ReadByte() == requiredFileType)
{
//Read the date parameters
int year = (int)reader.ReadByte() + 1900;
int month = (int)reader.ReadByte();
int day = (int)reader.ReadByte();
header.LastUpdateDate = new DateTime(year, month, day);
//Read the number of records.
header.NumRows = reader.ReadInt32();
//Read the length of the header structure.
header.HeaderLength = reader.ReadInt16();
//Read the length of a record
header.RowLength = reader.ReadInt16();
//Skip the reserved bytes in the header.
reader.BaseStream.Seek(20, SeekOrigin.Current);
//Calculate the number of columns in the header
header.NumColumns = (header.HeaderLength - fileDescriptionSize - 1) / fileDescriptionSize;
//Inialize the ColumDescriptions List
header.ColumnDescriptions = new List <DBaseColumnDefinition>(header.NumColumns);
for (int i = 0; i < header.NumColumns; i++)
{
DBaseColumnDefinition columnDescription = new DBaseColumnDefinition();
//Read the cloumn name
char[] buffer = new char[11];
buffer = reader.ReadChars(11);
columnDescription.Name = new string(buffer).Replace("\0", String.Empty);
//Read the column dBase data type
columnDescription.DBaseType = (char)reader.ReadByte();
//Skip the column data address
reader.ReadInt32();
//Read the column length in bytes
int columnLength = (int)reader.ReadByte();
//Make sure the length is positive
if (columnLength < 0)
{
columnLength += 256;
}
columnDescription.Length = columnLength;
//Skip the column decimal count property and the reserved bytes.
reader.BaseStream.Seek(15, SeekOrigin.Current);
//Add the column description to the list of descriptions
header.ColumnDescriptions.Add(columnDescription);
}
//The last byte is a marker for the end of the field definitions.
reader.BaseStream.Seek(1, SeekOrigin.Current);
}
return(header);
}
