/// <summary>
/// Test whether piece of text is CSV
/// </summary>
public static bool IsCsv(CsvStreamReader reader, char separator, int sampleRows)
{
List <int> _columnCount = new List <int>();
reader.Position = 0;
reader.Separator = separator;
while (!reader.EndOfCsvStream)
{
string[] _items = reader.ReadCsvLine().ToArray();
int _length = _items.Length == 1 && string.IsNullOrWhiteSpace(_items[0]) ? 0 : _items.Length;
if (_length > 0)
{
_columnCount.Add(_length);
}
}
int prevcount = _columnCount.First();
foreach (int count in _columnCount)
{
if (count == 1)
{
return(false);
}
if (count != prevcount)
{
return(false);
}
}
return(true);
}
/// <summary>
/// Returns a schema for the CSV with best fitted types to use.
/// </summary>
public static IEnumerable <CsvColumnInfo> GetCsvSchema(CsvStreamReader reader, int sampleRows)
{
bool _succes = CsvUtils.GetCsvSeparator(reader, out char _separator, sampleRows);
if (!_succes)
{
throw new ArgumentException("text is not valid csv!");
}
string[] _header = CsvHeader(reader, _separator);
NetType[] _columnTypes = new NetType[_header.Length];
bool[] _columnNullable = new bool[_header.Length];
reader.Position = 0;
bool _first = true;
int _row = 0;
while (!reader.EndOfCsvStream && (_row < sampleRows))
{
string[] _items = reader.ReadCsvLine().ToArray();
if (!_first)
{
for (int ii = 0; ii < _items.Length; ii++)
{
if (_items.Length == _header.Length)
{
NetType _netType = TypeUtils.BestNetType(_columnTypes[ii], _items[ii]);
if (_netType != NetType.Null)
{
_columnTypes[ii] = _netType;
}
else
{
if (_columnTypes[ii] != NetType.String && _columnTypes[ii] != NetType.Unknown)
{
_columnNullable[ii] = true;
}
}
}
}
}
_row++;
_first = false;
}
for (int ii = 0; ii < _header.Length; ii++)
{
yield return(new CsvColumnInfo()
{
Name = _header[ii],
DotNetType = _columnTypes[ii],
Nullable = _columnNullable[ii],
Index = ii,
DatabaseType = TypeUtils.GetDbType(_columnTypes[ii]),
SqlDatabaseType = TypeUtils.GetSqlDbType(_columnTypes[ii]),
IsLast = (ii == _header.Length - 1)
});
}
}
/// <summary>
/// Initialize and open the CSV Stream Reader.
/// </summary>
public void Open()
{
_Reader = new CsvStreamReader(_File, Encoding, DetectEncodingFromByteOrderMarks)
{
Separator = Separator
};
Init();
}
/// <summary>
/// Returns first row of CSV
/// </summary>
public static string[] CsvHeader(string text, char separator)
{
byte[] byteArray = Encoding.Default.GetBytes(text);
using MemoryStream _stream = new MemoryStream(byteArray);
using (CsvStreamReader _reader = new CsvStreamReader(_stream))
{
return(CsvHeader(_reader, separator));
}
}
/// <summary>
/// Test whether piece of text is CSV
/// </summary>
public static bool IsCsv(string text, char separator, int sampleRows)
{
byte[] byteArray = Encoding.Default.GetBytes(text);
var _columnCount = new List <int>();
using (MemoryStream _stream = new MemoryStream(byteArray))
{
using (CsvStreamReader _reader = new CsvStreamReader(_stream))
{
return(IsCsv(_reader, separator, sampleRows));
}
}
}
/// <summary>
/// Retrieves CSV separator from text.
/// </summary>
public static bool GetCsvSeparator(CsvStreamReader reader, out char separator, int sampleRows)
{
char[] _tests = new char[] { ',', ';', '\t', '|' };
foreach (char c in _tests)
{
if (IsCsv(reader, c, sampleRows))
{
separator = c;
return(true);
}
}
separator = ' ';
return(false);
}
/// <summary>
/// Returns first row of CSV
/// </summary>
public static string[] CsvHeader(CsvStreamReader reader, char separator)
{
reader.Position = 0;
reader.Separator = separator;
return(reader.ReadCsvLine().ToArray());
}
