/// <summary>
/// The read.
/// </summary>
/// <param name="module">The module.</param>
/// <returns>The <see cref="bool" />.</returns>
public bool Read(Iso8211Reader module)
{
if (!this._reuseHeader)
{
return(this.ReadHeader(module));
}
return(true);
}
/// <summary>
/// The read header.
/// </summary>
/// <param name="module">The module.</param>
/// <returns>The <see cref="bool" />.</returns>
/// <exception cref="System.ArgumentException">
/// Leader is short on file
/// or
/// Data record is short on DDF file.
/// or
/// Data record is short on DDF file.
/// </exception>
/// <exception cref="System.ApplicationException">
/// Data record appears to be corrupt on DDF file.\n ensure that the files were uncompressed without modifying\n carriage return/linefeeds (by default WINZIP does this).
/// or
/// or
/// </exception>
private bool ReadHeader(Iso8211Reader module)
{
if (module.Reader.BaseStream.Length == module.Reader.BaseStream.Position)
{
return(false);
}
var leader = new char[Constants.LeaderSize];
if (DdfUtils.ReadObjectsFromBuffer(module.Reader, leader, 0, Constants.LeaderSize, 1)
!= Constants.LeaderSize)
{
throw new ArgumentException("Leader is short on file");
}
DdfLeader ddfLeader = DdfUtils.CreateLeader(leader, false);
this._reuseHeader = ddfLeader.LeaderIdentifier == "R";
/* -------------------------------------------------------------------- */
/* Is there anything seemly screwy about this record? */
/* -------------------------------------------------------------------- */
if ((ddfLeader.RecordLength < 24 || ddfLeader.RecordLength > 100000000 || ddfLeader.FieldAreaStart < 24 ||
ddfLeader.FieldAreaStart > 100000) && (ddfLeader.RecordLength != 0))
{
throw new ApplicationException(
"Data record appears to be corrupt on DDF file.\n ensure that the files were uncompressed without modifying\n carriage return/linefeeds (by default WINZIP does this).");
}
if (ddfLeader.RecordLength != 0)
{
int dataSize = ddfLeader.RecordLength - Constants.LeaderSize;
this._data = new char[dataSize];
if (DdfUtils.ReadObjectsFromBuffer(module.Reader, this._data, 0, dataSize, 1) != dataSize)
{
throw new ArgumentException("Data record is short on DDF file.");
}
/* -------------------------------------------------------------------- */
/* If we don't find a field terminator at the end of the record */
/* we will read extra bytes till we get to it. */
/* -------------------------------------------------------------------- */
while (this._data[dataSize - 1] != Constants.DdfFieldTerminator &&
(dataSize == 0 || this._data[dataSize - 2] != Constants.DdfFieldTerminator))
{
dataSize++;
var moreData = new char[dataSize];
this._data.CopyTo(moreData, 0);
if (DdfUtils.ReadObjectsFromBuffer(module.Reader, moreData, dataSize, 1, 1) != 1)
{
throw new ArgumentException("Data record is short on DDF file.");
}
this._data = moreData;
}
int fieldEntryWidth = ddfLeader.GetFieldEntryWidth();
/* -------------------------------------------------------------------- */
/* Loop over the directory entries, making a pass counting them. */
/* -------------------------------------------------------------------- */
int fieldCount = DdfUtils.CountDirectoryEntries(this._data, 0, dataSize, fieldEntryWidth);
/* -------------------------------------------------------------------- */
/* Allocate, and read field definitions. */
/* -------------------------------------------------------------------- */
for (int i = 0; i < fieldCount; i++)
{
int entryOffset = i * fieldEntryWidth;
/* -------------------------------------------------------------------- */
/* Read the position information and tag. */
/* -------------------------------------------------------------------- */
var tag = new String(this._data.Skip(entryOffset).Take(ddfLeader.SizeFieldTag).ToArray());
entryOffset += ddfLeader.SizeFieldTag;
int fieldLength = DdfUtils.ReadIntFromBuffer(this._data, entryOffset, ddfLeader.SizeFieldLength);
entryOffset += ddfLeader.SizeFieldLength;
int fieldPos = DdfUtils.ReadIntFromBuffer(this._data, entryOffset, ddfLeader.SizeFieldPosition);
DdfFieldDefinition fieldDefn = module.FieldDefinitions.FirstOrDefault(f => f.Tag == tag);
if (fieldDefn == null)
{
throw new ApplicationException(
string.Format("Undefined field {0} encountered in data record.", tag));
}
if (ddfLeader.FieldAreaStart + fieldPos - Constants.LeaderSize < 0 ||
dataSize - (ddfLeader.FieldAreaStart + fieldPos - Constants.LeaderSize) < fieldLength)
{
throw new ApplicationException(string.Format("Not enough byte to initialize field {0}.", tag));
}
/* Assign info the DDFField. */
/* -------------------------------------------------------------------- */
this.Fields.Add(
new DdfField
{
FieldDefinition = fieldDefn,
Data = this._data,
Offset = ddfLeader.FieldAreaStart + fieldPos - Constants.LeaderSize,
DataSize = fieldLength
});
}
return(true);
}
return(true);
}
