Preserve input line ending style in output

[wegank]

Currently, msolve writes output files using the native line ending convention of the platform, regardless of the line endings used in the input. I suggest instead preserving the input line ending style of the input: if the input uses LF, the output should use LF; if the input uses CRLF, the output should use CRLF.

This issue is closely related to #182: a user working with CRLF files might expect the output to use CRLF so they can process the files in the same way. Otherwise, they will unfortunately have to run unix2dos on the output provided by msolve.

If you have any opinions (especially @vneiger who added CRLF support in #183), please write it below.

[vneiger]

preserving the input line ending style of the input

I think that would be preferable indeed (because much more user-friendly), if it's easy to tweak the code into having this behaviour.

[wegank]

I guess the simplest and safest way is to detect the line ending before core_msolve in src/msolve/main.c:

msolve/src/msolve/main.c

Lines 565 to 572 in 754adb7

	/* main msolve functionality */
	int ret = core_msolve(la_option, use_signatures, nr_threads, info_level,
	initial_hts, max_pairs, elim_block_len, update_ht,
	generate_pbm, reduce_gb, print_gb, truncate_lifting, get_param,
	genericity_handling, unstable_staircase, saturate, colon, normal_form,
	normal_form_matrix, is_gb, lift_matrix, precision,
	files, gens,
	&param, mpz_paramp, &nb_real_roots, &real_roots, &real_pts);

Then after core_msolve, rewrite files->out_file using the desired line ending, if necessary. Then it should only have an overhead if the line ending is not the native one.