Text Parser for C#

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Introduction

While .NET class BinaryReader provides many useful methods, e.g., ReadByte, ReadDouble, etc., there are no such methods in TextReader. As far as I know, there is neither a .NET class similar to good Java Scanner class (java.util.Scanner) nor a .NET class providing methods similar to C/C++ CRT function scanf. This means that the reading of text files may become, especially for beginners, a nightmare. The common way is to read the whole line, split it into tokens and convert these tokens into the required format (Byte, Double, Int32, ...) but it is not very convenient. Therefore I decided to program my own class to simplify text data processing.

Using the Code

ZCU.IO.TextParser is a small class written in C# 2.0 that is able to read text data from String or TextReader object. It provides methods for reading numbers, words, tokens matching the given pattern, etc. It also contains the method Scanf for formatted reading.

The following example, which can read 2D or 3D points from the text file, demonstrates the use of this class.

Input file 1

100
0.10330 0.00540
0.42320 0.49370
0.23690 0.56980

etc.

Input file 2

100
0.10330 0.00540 0.23690
0.42320 0.49370 0.23690
0.23690 0.56980 0.10330

etc.

The code for loading input files is as follows:

StreamReader lReader = new StreamReader(new FileStream(strFilePath, 
		FileMode.Open, FileAccess.Read, FileShare.Read),Encoding.UTF8);

ZCU.IO.TextParser parser = new ZCU.IO.TextParser(lReader);

//loads the number of points in the file
uint nNumVert = parser.ReadUInt32();
m_TriData.Vertices = new TRS_VERTEX[nNumVert];

//reads the first point
string line = parser.ReadLine();
ZCU.IO.TextParser line_parser = new ZCU.IO.TextParser(line);

//buffer for objects retrieved by Scanf
object[] xyz = new object[3];
xyz[2] = new System.Single();        //0,1(x,y) are always created by Scanf
string format = "%f %f %f\n";
if (line_parser.Scanf(format, xyz) < 3)
    format = "%f %f\n";              //z-coordinate not in file

List<STRING> formatList = ZCU.IO.TextParser.ConstructFormatList(format);

m_TriData.Vertices[0].x = (float)xyz[0];
m_TriData.Vertices[0].y = (float)xyz[1];
m_TriData.Vertices[0].z = (float)xyz[2];

for(uint i = 1; i < nNumVert; i++)
{
    parser.Scanf(formatList, xyz);
    m_TriData.Vertices[i].x = (float)xyz[0];
    m_TriData.Vertices[i].y = (float)xyz[1];
    m_TriData.Vertices[i].y = (float)xyz[2];
}

Points of Interest

The source code can be used, modified and redistributed under the terms of the license agreement that is included in the deployment package.

History

• 26.10.2006 - version 1.0