public static Func <object[], T> CreateMapper <T>(this Dbf dbf) where T : class, new()
{
var fields = dbf.GetHeader().Fields;
var type = typeof(T);
var props = type.GetProperties();
var methodBody = new List <Expression>();
var rowParam = Expression.Parameter(typeof(object[]), "row");
var hoistedLocalVariable = Expression.Property(Expression.Constant(new ValueBag <T>()), "Value");
methodBody.Add(Expression.Assign(hoistedLocalVariable, Expression.New(type)));
for (int i = 0; i < fields.Count; i++)
{
var field = fields[i];
var prop = props.FirstOrDefault(x => x.Name.Equals(field.Name, StringComparison.OrdinalIgnoreCase));
if (prop is null)
{
continue;
}
var value = Expression.ArrayIndex(rowParam, Expression.Constant(field.Index));
var access = Expression.MakeMemberAccess(hoistedLocalVariable, prop);
var setter = Expression.Assign(access, Expression.Convert(value, prop.PropertyType));
methodBody.Add(setter);
}
var returnTarget = Expression.Label(type);
methodBody.Add(Expression.Return(returnTarget, hoistedLocalVariable, type));
methodBody.Add(Expression.Label(returnTarget, hoistedLocalVariable));
var lambda = Expression.Lambda <Func <object[], T> >(Expression.Block(methodBody), rowParam);
return(lambda.Compile());
}
public DbfReader(Dbf dbf, Encoding textEncoding)
{
DbfTypeMap.Add('C', (i, b, f, e) =>
{
if (f.Length == 1)
{
return(e.GetString(b)[0]);
}
return(e.GetString(b).TrimEnd('\0'));
});
DbfTypeMap.Add('M', (i, b, f, e) => BitConverter.ToInt32(b));
DbfTypeMap.Add('W', (i, b, f, e) => BitConverter.ToInt32(b));
DbfTypeMap.Add('G', (i, b, f, e) => BitConverter.ToInt32(b));
DbfTypeMap.Add('Y', (i, b, f, e) => BitConverter.ToInt64(b) / 10000m); // Stored as int64 with 4 implicit decimal places
DbfTypeMap.Add('D', (i, b, f, e) =>
{
var dateStr = e.GetString(b).Trim(); return(dateStr == "" ? DateTime.MinValue : DateTime.ParseExact(dateStr, "yyyyMMdd", null));
});
DbfTypeMap.Add('T', (i, b, f, e) => JulianDateHelper.FromULongBuffer(b));
DbfTypeMap.Add('N', (i, b, f, e) =>
{
var numStr = e.GetString(b).Trim();
if (f.DecimalCount == 0)
{
if (f.Length < 3)
{
if (numStr == "")
{
return((byte)0);
}
return(byte.Parse(numStr));
}
else if (f.Length < 5)
{
if (numStr == "")
{
return((short)0);
}
return(short.Parse(numStr));
}
else if (f.Length < 10)
{
if (numStr == "")
{
return((int)0);
}
return(int.Parse(numStr));
}
else if (f.Length < 19)
{
if (numStr == "")
{
return((long)0);
}
return(long.Parse(numStr));
}
}
return(numStr == "" ? 0m : decimal.Parse(numStr));
});
DbfTypeMap.Add('B', (i, b, f, e) => BitConverter.ToInt32(b));
DbfTypeMap.Add('O', (i, b, f, e) => BitConverter.ToDouble(b));
DbfTypeMap.Add('F', (i, b, f, e) => { var numStr = e.GetString(b).Trim(); return(numStr == "" ? 0f : float.Parse(numStr)); });
DbfTypeMap.Add('I', (i, b, f, e) => BitConverter.ToInt32(b));
DbfTypeMap.Add('L', (i, b, f, e) => BitConverter.ToBoolean(b));
DbfTypeMap.Add('Q', CopyFieldBuffer);
DbfTypeMap.Add('P', CopyFieldBuffer);
this.dbf = dbf;
TextEncoding = textEncoding;
dbfHeader = dbf.GetHeader();
if (IsVisualFoxPro(dbfHeader))
{ // Special handling for VFP
DbfTypeMap['B'] = (i, b, f, e) => BitConverter.ToDouble(b);
// VarChar/VarBinary
// SPECIAL CASE for VARCHAR/BINARY
DbfTypeMap['V'] = (i, b, f, e) => f.Flags.HasFlag(DbfFieldFlags.Binary) ? CopyFieldBuffer(i, b, f, e) : e.GetString(b);
// _NullFlags
nullField = dbfHeader.Fields.FirstOrDefault(x => x.Type == '0');
nullFieldDataHandler = DbfTypeMap['0'] = CopyFieldBuffer;
if (nullField != null)
{
if (nullField.Length == 1)
{
nullFieldHandlerFactory = (i, b, f, e) => new UIntNullFieldHandler(b[0]);
}
else
{
nullFieldHandlerFactory = (i, b, f, e) => new BitArrayNullFieldHandler(b.ToArray());
}
}
}
}
/// <summary>
/// Creates an instance with <see cref="TextEncoding"/> being codepage 1252.
/// </summary>
public DbfReader(Dbf dbf)
: this(dbf, CodePagesEncodingProvider.Instance.GetEncoding(1252))
{
}
