Issue for use constant memory with merge ranger

[tritueviet]

I am using libxlsxwriter to do export excel has a lot of merge cell range with constant memory support, but it not working because it not supported. Here is some code that demonstrates the problem:

`#include "xlsxwriter.h"

int main() { lxw_workbook_options options = {.constant_memory = LXW_TRUE, .tmpdir = NULL, .use_zip64 = LXW_FALSE, .output_buffer = NULL, .output_buffer_size = NULL}; lxw_workbook *workbook = workbook_new_opt("merge_range.xlsx", &options); lxw_worksheet *worksheet = workbook_add_worksheet(workbook, NULL); lxw_format *merge_format = workbook_add_format(workbook);

/* Configure a format for the merged range. */
format_set_align(merge_format, LXW_ALIGN_CENTER);
format_set_align(merge_format, LXW_ALIGN_VERTICAL_CENTER);
format_set_bold(merge_format);
format_set_bg_color(merge_format, LXW_COLOR_YELLOW);
format_set_border(merge_format, LXW_BORDER_THIN);

/* Increase the cell size of the merged cells to highlight the formatting. */
worksheet_set_column(worksheet, 1, 3, 12, NULL);
worksheet_set_row(worksheet, 3, 30, NULL);
worksheet_set_row(worksheet, 6, 30, NULL);
worksheet_set_row(worksheet, 7, 30, NULL);

/* Merge 3 cells. */
worksheet_merge_range(worksheet, 3, 1, 3, 3, "Merged Range", merge_format);

/* Merge 3 cells over two rows. */
worksheet_merge_range(worksheet, 6, 1, 7, 3, "Merged Range", merge_format);

workbook_close(workbook);

return 0;

} `

Can you support this function in constant memory?