public static List <List <string> > ReadCsvFile(string fn, Encoding enc, int maxlines = -1)
{
List <List <string> > lines = new List <List <string> >();
int nline = 0;
StreamReaderEx.OpenSteamForRead(fn, enc, sr =>
{
while (!sr.EndOfStream && (maxlines <= 0 || nline < maxlines))
{
nline++;
var line = CsvFileHelper.GetLine(sr);
bool hasNullVal = true;
foreach (var fieldVal in line)
{
if (!string.IsNullOrEmpty(fieldVal))
{
hasNullVal = false;
break;
}
}
if (!hasNullVal)
{
lines.Add(line);
}
}
});
return(lines);
}
private static int GetNextQuote(ref string s, int sidx, StreamReader sr)
{
int i = -1;
while (i < 0)
{
i = s.IndexOf('"', sidx);
if (i < 0)
{
int length = s.Length;
s = s + "\r\n" + sr.ReadLine();
sidx = length + 2;
}
else
{
int cnt = CsvFileHelper.CountContinuousQuotes(s, i);
if (cnt % 2 == 1)
{
i += cnt - 1;
}
else
{
sidx = i + cnt;
i = -1;
}
}
}
return(i);
}
private static int GetRightQuote(ref string s, int startIdx, StreamReader sr)
{
int nextQuote = CsvFileHelper.GetNextQuote(ref s, startIdx, sr);
Util.Assert(CsvFileHelper.IsRightQuote(s, nextQuote));
return(nextQuote);
}
private static List <string> GetLine(StreamReader sr)
{
var line = new List <string>();
var val = sr.ReadLine();
while (!string.IsNullOrEmpty(val))
{
string oneField = CsvFileHelper.GetOneField(ref val, sr);
line.Add(oneField);
}
return(line);
}
private static string GetOneField(ref string s, StreamReader sr)
{
int n = CsvFileHelper.CountContinuousQuotes(s, 0);
if (CsvFileHelper.IsStartWithQuote(s, n))
{
return(CsvFileHelper.GetQuoteField(ref s, n, sr));
}
var rtVal = string.Empty;
int len = s.IndexOf(',');
if (len < 0)
{
len = s.Length;
}
rtVal = ((len == 0) ? "" : s.Substring(0, len));
s = ((len >= s.Length - 1) ? "" : s.Substring(len + 1));
return(rtVal);
}
private static string GetQuoteField(ref string s, int n, StreamReader sr)
{
var fieldVal = string.Empty;
if (n % 2 == 0)
{
Util.Assert(s[n] == ',');
fieldVal = ((n == 2) ? "" : s.Substring(1, n - 2));
s = ((s.Length > n + 1) ? s.Substring(n + 1) : "");
}
else
{
int rightQuote = CsvFileHelper.GetRightQuote(ref s, n, sr);
Util.Assert(rightQuote > n);
fieldVal = s.Substring(1, rightQuote - 1);
s = ((s.Length > rightQuote + 2) ? s.Substring(rightQuote + 2) : "");
}
if (fieldVal.Length > 0 && fieldVal[0] == '\t')
{
fieldVal = fieldVal.Substring(1);
}
return(fieldVal.Replace("\"\"", "\""));
}
public static void WriteCsvFile(List <List <string> > lines, string fn, HashSet <int> dontEncodeColumns = null)
{
CsvFileHelper.WriteCsvFile(lines, fn, Encoding.GetEncoding("gb2312"), dontEncodeColumns);
}
public static List <List <string> > ReadCsvFile(string fn, int maxlines = -1)
{
return(CsvFileHelper.ReadCsvFile(fn, Encoding.GetEncoding("gb2312"), maxlines));
}
