/// <summary>
/// Find how many rows to read at a time and their offset in the file.
/// If rows are stored sequentially in the file, returns a block size of up to 32 rows.
/// If rows are stored non-sequentially, the block size may extend up to the entire worksheet stream
/// </summary>
private void GetBlockSize(int startRow, out int blockRowCount, out int minOffset, out int maxOffset)
{
minOffset = int.MaxValue;
maxOffset = int.MinValue;
var i = 0;
blockRowCount = Math.Min(32, RowCount - startRow);
while (i < blockRowCount)
{
if (RowOffsetMap.TryGetValue(startRow + i, out var rowOffset))
{
minOffset = Math.Min(rowOffset.MinCellOffset, minOffset);
maxOffset = Math.Max(rowOffset.MaxCellOffset, maxOffset);
if (rowOffset.MaxOverlapRowIndex != int.MinValue)
{
var maxOverlapRowCount = rowOffset.MaxOverlapRowIndex + 1;
blockRowCount = Math.Max(blockRowCount, maxOverlapRowCount - startRow);
}
}
i++;
}
}
private XlsRowBlock ReadNextBlock(XlsBiffStream biffStream, int startRow, int rows, int minOffset, int maxOffset)
{
var result = new XlsRowBlock {
Rows = new Dictionary <int, Row>()
};
// Ensure rows with physical records are initialized with height
for (var i = 0; i < rows; i++)
{
if (RowOffsetMap.TryGetValue(startRow + i, out _))
{
EnsureRow(result, startRow + i);
}
}
if (minOffset == int.MaxValue)
{
return(result);
}
biffStream.Position = minOffset;
XlsBiffRecord rec;
XlsBiffRecord ixfe = null;
while (biffStream.Position <= maxOffset && (rec = biffStream.Read()) != null)
{
if (rec.Id == BIFFRECORDTYPE.IXFE)
{
// BIFF2: If cell.xformat == 63, this contains the actual XF index >= 63
ixfe = rec;
}
if (rec.IsCell)
{
var cell = (XlsBiffBlankCell)rec;
var currentRow = EnsureRow(result, cell.RowIndex);
if (cell.Id == BIFFRECORDTYPE.MULRK)
{
var cellValues = ReadMultiCell(cell);
currentRow.Cells.AddRange(cellValues);
}
else
{
var xfIndex = GetXfIndexForCell(cell, ixfe);
var cellValue = ReadSingleCell(biffStream, cell, xfIndex);
currentRow.Cells.Add(cellValue);
}
ixfe = null;
}
}
return(result);
}
private void SetMinMaxRow(int rowIndex, XlsBiffRow row)
{
if (!RowOffsetMap.TryGetValue(rowIndex, out var rowOffset))
{
rowOffset = new XlsRowOffset();
rowOffset.MinCellOffset = int.MaxValue;
rowOffset.MaxCellOffset = int.MinValue;
rowOffset.MaxOverlapRowIndex = int.MinValue;
RowOffsetMap.Add(rowIndex, rowOffset);
}
rowOffset.Record = row;
}
private void SetMinMaxRowOffset(int rowIndex, int recordOffset, int maxOverlapRow)
{
if (!RowOffsetMap.TryGetValue(rowIndex, out var rowOffset))
{
rowOffset = new XlsRowOffset();
rowOffset.MinCellOffset = int.MaxValue;
rowOffset.MaxCellOffset = int.MinValue;
rowOffset.MaxOverlapRowIndex = int.MinValue;
RowOffsetMap.Add(rowIndex, rowOffset);
}
rowOffset.MinCellOffset = Math.Min(recordOffset, rowOffset.MinCellOffset);
rowOffset.MaxCellOffset = Math.Max(recordOffset, rowOffset.MaxCellOffset);
rowOffset.MaxOverlapRowIndex = Math.Max(maxOverlapRow, rowOffset.MaxOverlapRowIndex);
}
private Row EnsureRow(XlsRowBlock result, int rowIndex)
{
if (!result.Rows.TryGetValue(rowIndex, out var currentRow))
{
var height = DefaultRowHeight / 20.0;
if (RowOffsetMap.TryGetValue(rowIndex, out var rowOffset) && rowOffset.Record != null)
{
height = (rowOffset.Record.UseDefaultRowHeight ? DefaultRowHeight : rowOffset.Record.RowHeight) / 20.0;
}
currentRow = new Row(rowIndex, height, new List <Cell>());
result.Rows.Add(rowIndex, currentRow);
}
return(currentRow);
}