public static IEnumerable <IEnumerable <string> > ParseCSV(this IEnumerable <char> stream,
bool trim = false,
bool skipHeader = false,
int columns = -1,
bool skipIfMore = false,
bool addIfLess = false)
{
var enumerator = new CharIteratorWithStats(stream.AsLookAheadEnumerable().GetLookAheadEnumerator(), columns);
var sb = new StringBuilder();
var ws = new StringBuilder();
if (skipHeader && enumerator.HasNext)
{
enumerator.DetectCount = columns < 0;
foreach (var value in parseCSVRow(enumerator, trim, skipIfMore, addIfLess, sb, ws))
{
;
}
}
enumerator.DetectCount = columns < 0;
while (enumerator.HasNext)
{
yield return(parseCSVRow(enumerator, trim, skipIfMore, addIfLess, sb, ws));
}
}
private static IEnumerable <string> parseCSVRow(CharIteratorWithStats enumerator, bool trim, bool skipIfMore, bool addIfLess, StringBuilder sb, StringBuilder ws)
{
if (sb.Length != 0)
{
throw new CSVParserException("{0}.ParseCSVRow(!sb.empty)".Args(enumerator.GetType().Name), enumerator.Line, enumerator.Column);
}
if (ws.Length != 0)
{
throw new CSVParserException("{0}.ParseCSVRow(!ws.empty)".Args(enumerator.GetType().Name), enumerator.Line, enumerator.Column);
}
var state = State.None;
enumerator.Count = 0;
while (enumerator.MoveNext())
{
var c = enumerator.Current;
if (('\n' == c || '\r' == c) && state != State.Quote)
{
if ('\r' == c && enumerator.HasNext && '\n' == enumerator.Next)
{
enumerator.MoveNext();
}
break;
}
if (char.IsWhiteSpace(c))
{
ws.Append(c);
continue;
}
switch (state)
{
case State.None:
if ('"' == c && (ws.Length == 0 || trim))
{
state = State.Quote;
ws.Clear();
}
else if (',' == c)
{
if (!trim)
{
sb.Append(ws.ToString());
}
ws.Clear();
if (!(skipIfMore && enumerator.RequiredCount >= 0 && enumerator.Count >= enumerator.RequiredCount))
{
enumerator.Count++;
yield return(sb.ToString());
}
sb.Clear();
}
else
{
state = State.Value;
if (!trim)
{
sb.Append(ws.ToString());
}
ws.Clear();
sb.Append(c);
}
break;
case State.Value:
if (',' == c)
{
state = State.None;
if (!trim)
{
sb.Append(ws.ToString());
}
ws.Clear();
if (!(skipIfMore && enumerator.RequiredCount >= 0 && enumerator.Count >= enumerator.RequiredCount))
{
enumerator.Count++;
yield return(sb.ToString());
}
sb.Clear();
}
else
{
sb.Append(ws.ToString());
ws.Clear();
sb.Append(c);
}
break;
case State.Quote:
if ('"' == c)
{
sb.Append(ws.ToString());
ws.Clear();
if (enumerator.HasNext && '"' == enumerator.Next)
{
sb.Append(c);
enumerator.MoveNext();
}
else
{
state = State.AfterQuote;
}
}
else
{
sb.Append(ws.ToString());
ws.Clear();
sb.Append(c);
}
break;
case State.AfterQuote:
if (',' == c)
{
state = State.None;
if (!trim)
{
sb.Append(ws.ToString());
}
ws.Clear();
if (!(skipIfMore && enumerator.RequiredCount >= 0 && enumerator.Count >= enumerator.RequiredCount))
{
enumerator.Count++;
yield return(sb.ToString());
}
sb.Clear();
}
else
{
throw new CSVParserException("{0}.parseCSVRow()".Args(enumerator.GetType().Name), enumerator.Line, enumerator.Column);
}
break;
}
}
if (!trim && state != State.AfterQuote)
{
sb.Append(ws.ToString());
}
else if (!trim && state == State.AfterQuote && ws.Length != 0)
{
throw new CSVParserException("{0}.ParseCSVRow()".Args(enumerator.GetType().Name), enumerator.Line, enumerator.Column);
}
ws.Clear();
if (!(skipIfMore && enumerator.RequiredCount >= 0 && enumerator.Count >= enumerator.RequiredCount))
{
enumerator.Count++;
yield return(sb.ToString());
}
if (addIfLess && enumerator.RequiredCount >= 0)
{
for (; enumerator.Count < enumerator.RequiredCount; enumerator.Count++)
{
yield return(string.Empty);
}
}
if (enumerator.RequiredCount >= 0 && enumerator.Count != enumerator.RequiredCount)
{
throw new CSVParserException("{0}.parseCSVRow(Count!=RequiredCount)({1}!={2})".Args(enumerator.GetType().Name, enumerator.Count, enumerator.RequiredCount), enumerator.Line, enumerator.Column);
}
if (enumerator.RequiredCount < 0 && enumerator.DetectCount)
{
enumerator.RequiredCount = enumerator.Count;
}
sb.Clear();
}
