Iterating over it returns each side number in turn. This allows
converting many loops of the form:
```
for (int i = 0; i < MAX_SIDES_PER_SEGMENT; ++i)
```
to the compact form:
```
for (const auto i : MAX_SIDES_PER_SEGMENT)
```
The compact form brings the usual benefit of range-based for: delegating
iteration to the compiler prevents the loop body from skipping a step,
and makes clear in the code that this is the case.
It has never worked correctly. It compares real vertex numbers (as used
to index in Vertices[]) to abstract vertex numbers (always in the range
of [0, 7], as used on a theoretical segment.
Once the loop has determined a vertex is used at least twice, there is
no need to count how many more times it is used. Return immediately
after detecting the second use.
- Make it static
- Remove the update of Num_vertices, since the caller reverses that
update.
- Remove the reversal, since it is no longer needed.
- Remove the test and update of Vertices.count, because the caller
always passes a vertex number that makes the test false.
Define separate enum values for rotation data in both the high bits,
where it is usually kept, and the low bits, where it is sometimes used
for math or comparisons.
Define an enum value to represent the composite of the index and the
rotation, since the composite is not suitable for use as an array
subscript. Add helper functions to extract the component pieces.
segment inherits unique_segment, so unique_segment members can be
referenced from an instance of segment. Eventually, segment will be
removed. Adjust references to go through unique_segment to support this
change.
segment inherits unique_segment, so unique_segment members can be
referenced from an instance of segment. Eventually, segment will be
removed. Adjust references to go through unique_segment to support this
change.
