See https://github.com/kajott/TrackMeister/issues/7

This is also somewhat related to tick boundary rendering, because we need to decide whether to expose the intermediate state of hitting a skip pattern or not.

There are basically 3 approaches possible here:

1.

bool is_order_skip_pattern(int32 ordernum);
bool is_pattern_skip_pattern(int32 patternnum);
bool is_order_stop_pattern(int32 ordernum);
bool is_pattern_stop_pattern(int32 patternnum);

2.

int32 get_skip_pattern_num();
int32 get_stop_pattern_num();

3.

enum pattern_type {
 normal,
 skip,
 stop,
};
pattern_type get_order_pattern_type(int32 ordernum);
pattern_type get_pattern_pattern_type(int32 patternum);

I have no idea which one would be best. Suggested names are not final, of course.

Option 2 has the disadvantage of requiring an API change if there ever should be multiple possible magic numbers per type.

In fact the skip / stop indices used to differ between formats, for no good reason. I unified them a long time ago and I don't think we'd ever want to go back to that.

Option 2 would allow for writing code with the fewest calls into libopenmpt - the values would only have to be retrieved once and then the whole order list can be processed using those values. Of course it would mean that adding a new type of pattern index would require a new function instead of just adding a new enum value - but with 50+ formats supported by now, and with the knowledge of other formats that are currently unsupported, I'm not even sure what that new type of pattern could be.