PR Details

Optimizing memory usage by pre-allocation.

Description

ColumnNumberToName Function:
- The ColumnNumberToName function previously concatenated rows using the + operator, leading to significant memory allocation when called frequently.
- The function now uses a pre-allocated slice to build the Excel column name. During construction, the converted number to letter is added to this slice. At the end, the slice of runes is converted to a string and returned.
Sheet Pre-allocation:
- Added an option to create a Sheet with pre-allocated rows.
- The xlsxWorksheet structure now contains a field with a slice type. When calling the SetCell... function to add a row to the sheet, it in turn calls the prepareSheetXML function. This function adds an xlsxRow structure to the slice.
- Previously, multiple calls to prepareSheetXML caused the slice to grow, allocating a lot of memory and performing unnecessary copying. The new approach pre-allocates the maximum number of rows, reducing memory allocations and copying overhead.

When working with a lot of data, some functions create many objects and trigger garbage collection (GC). The GC then loads the processor.
This optimization reduces memory allocations and the associated GC overhead, improving performance.

The changes have been tested in a development environment with datasets of varying sizes.
Benchmark tests were added to measure performance improvements in memory usage and processing time.
Existing unit tests were run to ensure no regressions were introduced.

[ ] Docs change / refactoring / dependency upgrade
[ ] Bug fix (non-breaking change which fixes an issue)
[x] New feature (non-breaking change which adds functionality)
[ ] Breaking change (fix or feature that would cause existing functionality to change)

Feel free to modify any part of this to better fit your needs!