FixedLengthField.cs :  » Persistence-Frameworks » FileHelpers-Library » FileHelpers » C# / CSharp Open Source

#region "   Copyright 2005-07 to Marcos Meli - http://www.marcosmeli.com.ar" 

// Errors, suggestions, contributions, send a mail to: marcos@filehelpers.com.

#endregion

using System.Reflection;
using System;
using System.Text;

namespace FileHelpers{
  internal sealed class FixedLengthField : FieldBase
  {
    #region "  Properties  "

    internal int mFieldLength;
    internal FieldAlignAttribute mAlign = new FieldAlignAttribute(AlignMode.Left, ' ');

    internal FixedMode mFixedMode = FixedMode.ExactLength;


    #endregion

    #region "  Constructor  "

    internal FixedLengthField(FieldInfo fi, int length, FieldAlignAttribute align) : base(fi)
    {
      this.mFieldLength = length;

      if (align != null)
        this.mAlign = align;
      else
      {
        if (fi.FieldType == typeof(Int16) ||
          fi.FieldType == typeof(Int32) ||
          fi.FieldType == typeof(Int64) ||
          fi.FieldType == typeof(UInt16) ||
          fi.FieldType == typeof(UInt32) ||
          fi.FieldType == typeof(UInt64) ||
          fi.FieldType == typeof(byte) ||
          fi.FieldType == typeof(sbyte) ||
          fi.FieldType == typeof(decimal) ||
          fi.FieldType == typeof(float) ||
          fi.FieldType == typeof(double))

          mAlign = new FieldAlignAttribute(AlignMode.Right, ' ');
      }
    }

    #endregion

    #region "  Overrides String Handling  "

    protected override ExtractedInfo ExtractFieldString(LineInfo line)
    {
      if (line.CurrentLength == 0)
      {
        if (mIsOptional)
          return ExtractedInfo.Empty;
        else
          throw new BadUsageException("End Of Line found processing the field: " + mFieldInfo.Name + " at line "+ line.mReader.LineNumber.ToString() + ". (You need to mark it as [FieldOptional] if you want to avoid this exception)");
      }
      
      ExtractedInfo res;

      if (line.CurrentLength < this.mFieldLength)
        if (mFixedMode == FixedMode.AllowLessChars || mFixedMode == FixedMode.AllowVariableLength)
          res = new ExtractedInfo(line);
        else
          throw new BadUsageException("The string '" + line.CurrentString + "' (length " + line.CurrentLength.ToString() + ") at line "+ line.mReader.LineNumber.ToString() + " has less chars than the defined for " + mFieldInfo.Name + " (" + mFieldLength.ToString() + "). You can use the [FixedLengthRecord(FixedMode.AllowLessChars)] to avoid this problem.");
      else if (mIsLast && line.CurrentLength > mFieldLength && mFixedMode != FixedMode.AllowMoreChars && mFixedMode != FixedMode.AllowVariableLength)
        throw new BadUsageException("The string '" + line.CurrentString + "' (length " + line.CurrentLength.ToString() + ") at line "+ line.mReader.LineNumber.ToString() + " has more chars than the defined for the last field " + mFieldInfo.Name + " (" + mFieldLength.ToString() + ").You can use the [FixedLengthRecord(FixedMode.AllowMoreChars)] to avoid this problem.");
      else
        res = new ExtractedInfo(line, line.mCurrentPos + mFieldLength);

      return res;
    }

    protected override void CreateFieldString(StringBuilder sb, object fieldValue)
    {
      string field = base.BaseFieldString(fieldValue);

      if (field.Length > mFieldLength)
        field = field.Substring(0, mFieldLength);
        //sb.Length = length + this.mFieldLength;

      if (mAlign.Align == AlignMode.Left)
      {
        sb.Append(field);
        sb.Append(mAlign.AlignChar, mFieldLength - field.Length);
      }
      else if (mAlign.Align == AlignMode.Right)
      {
        sb.Append(mAlign.AlignChar, mFieldLength - field.Length);
        sb.Append(field);
      }
      else
      {
        int middle = (mFieldLength - field.Length) / 2;

        sb.Append(mAlign.AlignChar, middle);
        sb.Append(field);
        sb.Append(mAlign.AlignChar,  mFieldLength - field.Length - middle);
//        if (middle > 0)
//          res = res.PadLeft(mFieldLength - middle, mAlign.AlignChar).PadRight(mFieldLength, mAlign.AlignChar);
      }
    }

    #endregion
  }
}