Lots of warnings

[markand]

Hello,

Thank you for this awesome library, I just get a lots of warnings when compiling with -Wall -Wextra:

$ gcc -std=c99 -Wall -Wextra md4c.c -c
md4c.c: In function ‘md_decode_unicode’:
md4c.c:844:52: warning: unused parameter ‘str_size’ [-Wunused-parameter]
     md_decode_unicode(const CHAR* str, OFF off, SZ str_size, SZ* p_size)
                                                    ^~~~~~~~
md4c.c: In function ‘md_merge_lines’:
md4c.c:864:73: warning: unused parameter ‘n_lines’ [-Wunused-parameter]
 md_merge_lines(MD_CTX* ctx, OFF beg, OFF end, const MD_LINE* lines, int n_lines,
                                                                         ^~~~~~~
md4c.c: In function ‘md_is_hex_entity_contents’:
md4c.c:1275:35: warning: unused parameter ‘ctx’ [-Wunused-parameter]
 md_is_hex_entity_contents(MD_CTX* ctx, const CHAR* text, OFF beg, OFF max_end, OFF* p_end)
                                   ^~~
md4c.c: In function ‘md_is_dec_entity_contents’:
md4c.c:1291:35: warning: unused parameter ‘ctx’ [-Wunused-parameter]
 md_is_dec_entity_contents(MD_CTX* ctx, const CHAR* text, OFF beg, OFF max_end, OFF* p_end)
                                   ^~~
md4c.c: In function ‘md_is_named_entity_contents’:
md4c.c:1307:37: warning: unused parameter ‘ctx’ [-Wunused-parameter]
 md_is_named_entity_contents(MD_CTX* ctx, const CHAR* text, OFF beg, OFF max_end, OFF* p_end)
                                     ^~~
md4c.c: In function ‘md_free_attribute’:
md4c.c:1412:27: warning: unused parameter ‘ctx’ [-Wunused-parameter]
 md_free_attribute(MD_CTX* ctx, MD_ATTRIBUTE_BUILD* build)
                           ^~~
md4c.c: In function ‘md_rollback’:
md4c.c:2618:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(i = 1; i < SIZEOF_ARRAY(ctx->mark_chains); i++) {
                  ^
md4c.c: In function ‘md_build_mark_char_map’:
md4c.c:2719:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for(i = 0; i < sizeof(ctx->mark_char_map); i++) {
                      ^
md4c.c: In function ‘md_collect_marks’:
md4c.c:2936:52: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
                 for(scheme_index = 0; scheme_index < SIZEOF_ARRAY(scheme_map); scheme_index++) {
                                                    ^
md4c.c: In function ‘md_process_verbatim_block_contents’:
md4c.c:4312:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         while(indent > SIZEOF_ARRAY(indent_chunk_str)) {
                      ^
md4c.c: In function ‘md_is_atxheader_line’:
md4c.c:4786:61: warning: unused parameter ‘p_end’ [-Wunused-parameter]
 md_is_atxheader_line(MD_CTX* ctx, OFF beg, OFF* p_beg, OFF* p_end, unsigned* p_level)
                                                             ^~~~~
md4c.c: At top level:
md4c.c:5336:1: warning: missing initializer for field ‘beg’ of ‘MD_LINE_ANALYSIS {aka const struct MD_LINE_ANALYSIS_tag}’ [-Wmissing-field-initializers]
 static const MD_LINE_ANALYSIS md_dummy_blank_line = { MD_LINE_BLANK, 0 };
 ^~~~~~
md4c.c:189:9: note: ‘beg’ declared here
     OFF beg;
         ^~~
md4c.c: In function ‘md_analyze_line’:
md4c.c:5481:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
                ctx->n_block_bytes > sizeof(MD_BLOCK))
                                   ^
md4c.c:5499:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
                ctx->n_block_bytes > sizeof(MD_BLOCK))
                                   ^
md4c.c: In function ‘md_parse’:
md4c.c:5908:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(i = 0; i < SIZEOF_ARRAY(ctx.mark_chains); i++) {
                  ^
md4c.c: In function ‘md_rollback’:
md4c.c:2669:19: warning: this statement may fall through [-Wimplicit-fallthrough=]
                 if((mark_flags & MD_MARK_CLOSER)  &&  mark->prev > opener_index) {
                   ^
md4c.c:2676:13: note: here
             default:
             ^~~~~~~
md4c.c: In function ‘md_process_inlines’:
md4c.c:3956:23: warning: this statement may fall through [-Wimplicit-fallthrough=]
                     if(!(mark->flags & MD_MARK_AUTOLINK)) {
                       ^
md4c.c:3966:17: note: here
                 case '@':       /* Permissive e-mail autolink. */
                 ^~~~
md4c.c: In function ‘md_enter_child_containers’:
md4c.c:5197:33: warning: this statement may fall through [-Wimplicit-fallthrough=]
                 is_ordered_list = TRUE;
                                 ^
md4c.c:5200:13: note: here
             case _T('-'):
             ^~~~
md4c.c: In function ‘md_leave_child_containers’:
md4c.c:5240:33: warning: this statement may fall through [-Wimplicit-fallthrough=]
                 is_ordered_list = TRUE;
                                 ^
md4c.c:5243:13: note: here
             case _T('-'):
             ^~~~

[mity]

Fixed all -Wextra warnings I've got from gcc 7.2 in the PR #35.

I wonder whether the PR really improves the code quality or just adds some noise into the sources. I find especially 821b15b4f2bf2f7df0831fab4b7c07c17b0d8cc4 very ridiculous. Gosh, should compiler really dictate wording of a comment in order to make it shut up about some warning??

I have quite mixed feelings about the result and I need some time to consider whether merging something like this is really the good thing.

[markand]

Yes, I never understood fallthrough warnings. This is just stupid from GCC developers since C don't have any attribute to mark an explicit fallthrough in portable manner.