example of a simple csv reader

csv-reader.cs

public sealed class CsvReader : IDisposable
{
    private const char DefaultFieldChar = ',';
    private const char DefaultQuoteChar = '"';
    private const char DefaultEscapeChar = '\\';
    
    private readonly List<CsvLine> collection;
    private readonly StringBuilder buffer;
    private readonly Stream stream;
    private readonly StreamReader reader;
    private readonly char fieldChar;
    private readonly char quoteChar;
    private readonly char escapeChar;
    private readonly int skipToData;
    private bool skippedToData;
    private bool hasMoreData;
    private int lineNumber;
    
    public bool HasDataToRead
    {
        get { return hasMoreData; }
    }
    
    public CsvReader(Stream stream, char fieldChar, char quoteChar, char escapeChar, int skipToData)
    {
        this.stream = stream;
        this.fieldChar = fieldChar;
        this.quoteChar = quoteChar;
        this.escapeChar = escapChar;
        this.skipToData = skipToData;
        
        reader = new StreamReader(stream);
        buffer = new StringBuilder();
        collection = new List<CsvLine>();
        
        hasMoreData = true;
    }
    
    public void Dispose()
    {
        reader.Close();
        reader.Dispose();
    }
    
    public IEnumerable<CsvLine> ReadToEnd()
    {
        while (hasMoreData)
        {
            var tokens = Read();
            if (tokens != null)
                collection.Add(tokens);
        }
        
        return collection;
    }
    
    public CsvLine Read()
    {
        var line = GetNextLine();
        if (hasMoreData)
            return new CsvLine {
                LineNumber = lineNumber,
                Line = ParseLine(line)
            };
            
        return null;
    }
    
    private string GetNextLine()
    {
        if (!skippedToData)
        {
            for (var index = 0; index < skipToData; index++)
            {
                lineNumber++;
                reader.ReadLine();
            }
            
            skippedToData = true;
        }
        
        var line = reader.ReadLine();
        if (line == null)
            hasMoreData = false;
        else
            lineNumber++;
            
        return line;
    }
    
    private string[] ParseLine(string line)
    {
        if (line == null)
            return new string[0];
        
        var tokens = new List<string>();
        var inQuotes = false;
        buffer.Length = 0;
        
        do
        {
            if (inQuotes)
            {
                buffer.Append('\n');
                line = GetNextLine();
                if (line == null)
                    break;
            }
            
            var lineChars = line.ToCharArray();
            for (var index = 0; index < lineChars.Length; index++)
            {
                var lineChar = lineChars[index];
                var skipped = false;
                var escaped = false;
                var incremented = false;
                
                if (lineChar.Equals(escapeChar))
                {
                    lineChar = lineChars[index + 1];
                    escaped = true;
                    incremented = true;
                }
                
                if (lineChar.Equals(quoteChar))
                {
                    if (!escaped)
                    {
                        skipped = true;
                        inQuotes = !inQuotes;
                    }
                }
                else if ((lineChar.Equals(fieldChar)) && !inQuotes)
                {
                    tokens.Add(buffer.ToString().Trim());
                    buffer.Length = 0;
                    continue;
                }
                
                if (!skipped)
                    buffer.Append(lineChar);
                    
                if (incremented)
                    index++;
            }
        } while (inQuotes);
        
        tokens.Add(buffer.ToString().Trim());
        return tokens.ToArray();
    }
    
    public sealed class CsvLine
    {
        private string[] collection;
        
        public string this[int index]
        {
            get
            {
                if (index >= collection.Length)
                    return string.Empty;
                return collection[index];
            }
        }
        
        public int Length
        {
            get
            {
                if (collection == null)
                    return 0;
                return collection.Length;
            }
        }
        
        public string[] Line
        {
            get { return collection; }
            set { collection = value; }
        }
        
        public int LineNumber { get; set; }
    }
}