private TRecord[] ReadTable(Stream peStream)
{
var columns = new ColumnIndexAttribute[ColumnCount];
var fields = new FieldInfo[ColumnCount];
// map the fields to columns
foreach (var fld in typeof(TRecord).GetFields())
{
var indexAttr = fld
.GetCustomAttributes(false)
.OfType <ColumnIndexAttribute>()
.FirstOrDefault();
if (indexAttr != null)
{
int index = indexAttr.Index;
if (columns[index] != null || fields[index] != null)
{
throw new InvalidOperationException($"Duplicate field index {index} in record type {typeof(TRecord).FullName}");
}
columns[index] = indexAttr;
fields[index] = fld;
}
}
if (columns.Any(c => c == null) ||
fields.Any(f => f == null))
{
throw new InvalidOperationException($"Could not map all columns of record type {typeof(TRecord).FullName}.");
}
// map the stream data to fields.
var records = new TRecord[RowCount];
const int MaxFieldSize = 4;
var fieldBytes = new byte[MaxFieldSize];
for (int row = 0; row < RowCount; row++)
{
// note: in the case that TRecord is a struct, we box + unbox it so we can populate via reflection.
object rec = new TRecord();
int recBytes = 0;
for (int col = 0; col < ColumnCount; col++)
{
CMiniColDef colDef = _tableDef.m_Def.m_pColDefs[col];
if (recBytes != colDef.m_oColumn)
{
// skip past any padding bytes.
peStream.Seek(colDef.m_oColumn - recBytes, SeekOrigin.Current);
recBytes = colDef.m_oColumn;
}
peStream.Read(fieldBytes, 0, colDef.m_cbColumn);
fields[col].SetValue(rec, ConvertBytes(fieldBytes, colDef));
recBytes += colDef.m_cbColumn;
}
records[row] = (TRecord)rec;
}
return(records);
}
private object ConvertBytes(byte[] bytes, CMiniColDef column)
{
// read RIDs, CodedTokens
if (column.m_Type < MetaModel.iCodedTokenMax)
{
if (column.m_cbColumn == 2)
{
return(BitConverter.ToUInt16(bytes, 0));
}
else if (column.m_cbColumn == 4)
{
return(BitConverter.ToUInt32(bytes, 0));
}
throw new ArgumentException($"Unexpected data size for RID or Coded Token: {column.m_cbColumn} bytes");
}
else
{
// read types with specific values.
ColumnType type = (ColumnType)column.m_Type;
switch (type)
{
case ColumnType.String:
case ColumnType.Guid:
case ColumnType.Blob:
if (column.m_cbColumn == 2)
{
return(BitConverter.ToUInt16(bytes, 0));
}
else if (column.m_cbColumn == 4)
{
return(BitConverter.ToUInt32(bytes, 0));
}
break;
case ColumnType.SHORT:
if (column.m_cbColumn == 2)
{
return(BitConverter.ToInt16(bytes, 0));
}
break;
case ColumnType.USHORT:
if (column.m_cbColumn == 2)
{
return(BitConverter.ToUInt16(bytes, 0));
}
break;
case ColumnType.LONG:
if (column.m_cbColumn == 4)
{
return(BitConverter.ToInt32(bytes, 0));
}
break;
case ColumnType.ULONG:
if (column.m_cbColumn == 4)
{
return(BitConverter.ToUInt32(bytes, 0));
}
break;
case ColumnType.BYTE:
if (column.m_cbColumn == 1)
{
return(bytes[0]);
}
break;
default:
throw new ArgumentException($"Unrecognized column type '{type}'.");
}
throw new ArgumentException($"Unexpected data size for type {type}: {column.m_cbColumn} bytes");
}
}
