Import dotnetDBF for error handling.
This commit is contained in:
Patrick Fic
309
dotnetdbf/DBFField.cs
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309
dotnetdbf/DBFField.cs
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/*
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DBFField
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Class represents a "field" (or column) definition of a DBF data structure.
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This file is part of DotNetDBF packege.
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original author (javadbf): anil@linuxense.com 2004/03/31
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license: LGPL (http://www.gnu.org/copyleft/lesser.html)
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ported to C# (DotNetDBF): Jay Tuley <jay+dotnetdbf@tuley.name> 6/28/2007
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*/
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using System;
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using System.Diagnostics;
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using System.IO;
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using System.Text;
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namespace DotNetDBF
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{
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[DebuggerDisplay("Field:{Name}, Length:{FieldLength}")]
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public class DBFField
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{
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public const int SIZE = 32;
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public byte dataType; /* 11 */
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public byte decimalCount; /* 17 */
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public int fieldLength; /* 16 */
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public byte[] fieldName = new byte[11]; /* 0-10*/
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public byte indexFieldFlag; /* 31 */
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/* other class variables */
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public int nameNullIndex = 0;
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public int reserv1; /* 12-15 */
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public short reserv2; /* 18-19 */
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public short reserv3; /* 21-22 */
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public byte[] reserv4 = new byte[7]; /* 24-30 */
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public byte setFieldsFlag; /* 23 */
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public byte workAreaId; /* 20 */
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public DBFField()
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{
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}
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public DBFField(string fieldName, NativeDbType type)
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{
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Name = fieldName;
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DataType = type;
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}
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public DBFField(string fieldName,
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NativeDbType type,
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int fieldLength)
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{
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Name = fieldName;
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DataType = type;
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FieldLength = fieldLength;
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}
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public DBFField(string fieldName,
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NativeDbType type,
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int fieldLength,
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int decimalCount)
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{
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Name = fieldName;
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DataType = type;
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FieldLength = fieldLength;
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DecimalCount = decimalCount;
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}
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public int Size => SIZE;
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/**
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Returns the name of the field.
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@return Name of the field as String.
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*/
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public string Name
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{
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get => Encoding.ASCII.GetString(fieldName, 0, nameNullIndex);
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set
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{
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if (value == null)
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{
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throw new ArgumentException("Field name cannot be null");
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}
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if (value.Length == 0
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|| value.Length > 10)
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{
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throw new ArgumentException(
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"Field name should be of length 0-10");
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}
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fieldName = Encoding.ASCII.GetBytes(value);
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nameNullIndex = fieldName.Length;
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}
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}
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/**
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Returns the data type of the field.
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@return Data type as byte.
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*/
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public Type Type => Utils.TypeForNativeDBType(DataType);
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public NativeDbType DataType
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{
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get => (NativeDbType)dataType;
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set
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{
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switch (value)
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{
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case NativeDbType.Date:
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fieldLength = 8; /* fall through */
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goto default;
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case NativeDbType.Memo:
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fieldLength = 10;
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goto default;
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case NativeDbType.Logical:
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fieldLength = 1;
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goto default;
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default:
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dataType = (byte)value;
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break;
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}
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}
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}
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/**
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Returns field length.
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@return field length as int.
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*/
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public int FieldLength
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{
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get
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{
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if (DataType == NativeDbType.Char)
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{
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return fieldLength + (decimalCount * 256);
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}
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return fieldLength;
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}
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/**
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Length of the field.
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This method should be called before calling setDecimalCount().
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@param Length of the field as int.
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*/
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set
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{
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if (value <= 0)
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{
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throw new ArgumentException(
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"Field length should be a positive number");
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}
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switch (DataType)
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{
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case NativeDbType.Date:
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case NativeDbType.Memo:
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case NativeDbType.Logical:
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throw new NotSupportedException(
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"Cannot set length on this type of field");
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case NativeDbType.Char when value > 255:
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fieldLength = value % 256;
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decimalCount = (byte) (value / 256);
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return;
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default:
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fieldLength = value;
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break;
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}
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}
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}
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/**
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Returns the decimal part. This is applicable
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only if the field type if of numeric in nature.
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If the field is specified to hold integral values
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the value returned by this method will be zero.
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@return decimal field size as int.
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*/
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public int DecimalCount
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{
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get => decimalCount;
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/**
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Sets the decimal place size of the field.
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Before calling this method the size of the field
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should be set by calling setFieldLength().
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@param Size of the decimal field.
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*/
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set
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{
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if (value < 0)
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{
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throw new ArgumentException(
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"Decimal length should be a positive number");
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}
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if (value > fieldLength)
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{
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throw new ArgumentException(
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"Decimal length should be less than field length");
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}
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decimalCount = (byte) value;
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}
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}
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public bool Read(BinaryReader reader)
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{
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var t_byte = reader.ReadByte(); /* 0 */
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if (t_byte == DBFFieldType.EndOfField)
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{
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//System.out.println( "End of header found");
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return false;
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}
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reader.Read(fieldName, 1, 10); /* 1-10 */
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fieldName[0] = t_byte;
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for (var i = 0; i < fieldName.Length; i++)
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{
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if (fieldName[i]
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== 0)
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{
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nameNullIndex = i;
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break;
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}
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}
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dataType = reader.ReadByte(); /* 11 */
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reserv1 = reader.ReadInt32(); /* 12-15 */
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fieldLength = reader.ReadByte(); /* 16 */
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decimalCount = reader.ReadByte(); /* 17 */
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reserv2 = reader.ReadInt16(); /* 18-19 */
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workAreaId = reader.ReadByte(); /* 20 */
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reserv3 = reader.ReadInt16(); /* 21-22 */
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setFieldsFlag = reader.ReadByte(); /* 23 */
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reader.Read(reserv4, 0, 7); /* 24-30 */
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indexFieldFlag = reader.ReadByte(); /* 31 */
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return true;
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}
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/**
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Writes the content of DBFField object into the stream as per
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DBF format specifications.
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@param os OutputStream
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@throws IOException if any stream related issues occur.
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*/
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public void Write(BinaryWriter writer)
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{
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// Field Name
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writer.Write(fieldName); /* 0-10 */
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writer.Write(new byte[11 - fieldName.Length],
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0,
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11 - fieldName.Length);
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// data type
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writer.Write(dataType); /* 11 */
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writer.Write(reserv1); /* 12-15 */
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writer.Write((byte) fieldLength); /* 16 */
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writer.Write(decimalCount); /* 17 */
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writer.Write(reserv2); /* 18-19 */
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writer.Write(workAreaId); /* 20 */
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writer.Write(reserv3); /* 21-22 */
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writer.Write(setFieldsFlag); /* 23 */
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writer.Write(reserv4); /* 24-30*/
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writer.Write(indexFieldFlag); /* 31 */
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}
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/**
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Creates a DBFField object from the data read from the given DataInputStream.
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The data in the DataInputStream object is supposed to be organised correctly
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and the stream "pointer" is supposed to be positioned properly.
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@param in DataInputStream
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@return Returns the created DBFField object.
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@throws IOException If any stream reading problems occurs.
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*/
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internal static DBFField CreateField(BinaryReader reader)
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{
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var field = new DBFField();
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if (field.Read(reader))
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{
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return field;
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}
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else
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{
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return null;
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}
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}
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}
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}
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