/// <summary>
/// Create a fixed-length data file using the provided data table
/// </summary>
/// <param name="dt"></param>
/// <param name="options"></param>
/// <param name="filename"></param>
public void Write(DataTable dt, FixedLengthImportOptions options, string filename)
{
#region Sanity Checks
if (dt == null)
{
throw new ArgumentNullException("dt");
}
if (string.IsNullOrEmpty(filename))
{
throw new ArgumentNullException("filename");
}
#endregion
//ResizeTableMaxLength(dt);
var buffer = new byte[options.RecordLength];
using (var fs = new FileStream(filename, FileMode.Create, FileAccess.Write, FileShare.Read))
using (var w = new BinaryWriter(fs))
{
foreach (DataRow dr in dt.Rows)
{
#region initialize the buffer with spaces
for (int i = 0; i < buffer.Length; i++)
{
buffer[i] = 32;
}
#endregion
foreach (DataColumn dc in dt.Columns)
{
int start = options.Definition[dc.ColumnName].Start - 1;
int len = options.Definition[dc.ColumnName].Length;
var value = Encoding.ASCII.GetBytes((dr[dc] ?? string.Empty).ToString());
Array.Copy(value, 0, buffer, start, len);
}
w.Write(buffer);
if (!string.IsNullOrEmpty(options.NewlineChar))
{
w.Write(options.NewlineChar); // ends the row with the specified newline delimiter
}
}
w.Flush();
w.Close();
}
}
/// <summary>
/// Read the filename and return a DataTable
/// </summary>
/// <param name="filename"></param>
/// <param name="options"></param>
/// <returns></returns>
public DataTable Read(string filename, FixedLengthImportOptions options)
{
#region Sanity Checks
if (!File.Exists(filename))
{
throw new FileNotFoundException("File not found: " + filename);
}
if (options == null)
{
throw new ArgumentNullException("options");
}
if (options.Definition == null)
{
throw new ArgumentNullException("options.Definition");
}
if (options.Definition.Count == 0)
{
throw new ArgumentException("The list of field spec is empty");
}
if (options.Definition.RecordLength <= 0)
{
throw new ArgumentException("The record length must be greater than zero");
}
#endregion
var def = options.Definition;
int reclen = def.RecordLength;
var fi = new FileInfo(filename);
// make sure that file size is evenly divisible by the record length.
// If not, we will assume that the definition is not valid for this file.
if (fi.Length % reclen != 0)
{
throw new ArgumentException("File size does not break evenly by record length of " + reclen);
}
var dt = new DataTable();
dt.TableName = Path.GetFileNameWithoutExtension(filename);
#region Generate Data Columns
foreach (var item in def)
{
DataColumn dc = new DataColumn(item.Name);
dc.DataType = item.Type;
if (item.Type == typeof(string))
{
dc.MaxLength = item.Length;
}
dt.Columns.Add(dc);
}
#endregion
#region Populate Data Rows
int rownum = 0;
foreach (var buffer in FileUtil.ReadFile(filename, reclen, 0))
{
if (buffer.Length == 0)
{
continue;
}
rownum++;
var dr = dt.NewRow();
#region Convert data to column
foreach (var item in def)
{
string val;
#if SUPPORT_ENHANCE_FEATURES
if (item.Compute)
{
switch (item.Value.ToString().ToUpper())
{
case "COUNTER":
val = rownum.ToString();
break;
case "DATE":
val = DateTime.Now.ToShortDateString();
break;
case "TIME":
val = DateTime.Now.ToShortTimeString();
break;
case "DATETIME":
val = DateTime.Now.ToString("s");
break;
default:
throw new ArgumentException("unknown auto-compute key value = " + item.Value);
}
}
else
{
if (item.Start == -1)
{
val = StringUtil.Unescape(item.Value.ToString());
}
else
#else
{
#endif
{ val = ASCIIEncoding.ASCII.GetString(buffer, item.Start - 1, item.Length).Trim(); }
}
if (string.IsNullOrEmpty(val))
{
continue;
}
object value = DataConvert.ChangeType(val, null, item.Type);
if (value == null)
{
throw new ArgumentException(string.Format("Converting '{0}' to {1} failed: ", val, item.Type.FullName));
}
dr[item.Name] = value;
}
#endregion
dt.Rows.Add(dr);
}
#endregion
return(dt);
}
