static void coalesce(Value::Ranges* ranges, const Value::Range& range)
{
// Note that we assume that ranges has already been coalesced.
Value::Ranges result;
Value::Range temp = range;
for (int i = 0; i < ranges->range_size(); i++) {
const Value::Range& current = ranges->range(i);
// Check if current and range overlap. Note, we only need to
// compare with range and not with temp to check for overlap
// because we expect ranges to be coalesced to begin with!
if (current.begin() <= range.end() && current.end() >= range.begin() ) {
// Update temp with new boundaries.
temp.set_begin(std::min(range.begin(), current.begin()));
temp.set_end(std::max(range.end(), current.end()));
} else { // No overlap.
result.add_range()->MergeFrom(current);
}
}
result.add_range()->MergeFrom(temp);
*ranges = result;
}
static void remove(Value::Ranges* ranges, const Value::Range& range)
{
// Note that we assume that ranges has already been coalesced.
Value::Ranges result;
for (int i = 0; i < ranges->range_size(); i++) {
const Value::Range& current = ranges->range(i);
// Note that these if/else if conditionals are in a particular
// order. In particular, the last two assume that the "subsumes"
// checks have already occured.
if (range.begin() <= current.begin() && range.end() >= current.end()) {
// Range subsumes current.
// current: | |
// range: | |
// range: | |
// range: | |
// range: | |
} else if (range.begin() >= current.begin() &&
range.end() <= current.end()) {
// Range is subsumed by current.
// current: | |
// range: | |
// range: | |
// range: | |
ranges::add(&result, current.begin(), range.begin() - 1);
ranges::add(&result, range.end() + 1, current.end());
} else if (range.begin() <= current.begin() &&
range.end() >= current.begin()) {
// Range overlaps to the left.
// current: | |
// range: | |
// range: | |
ranges::add(&result, range.end() + 1, current.end());
} else if (range.begin() <= current.end() && range.end() >= current.end()) {
// Range overlaps to the right.
// current: | |
// range: | |
// range: | |
ranges::add(&result, current.begin(), range.begin() - 1);
} else {
// Range doesn't overlap current.
// current: | |
// range: | |
// range: | |
ranges::add(&result, current.begin(), current.end());
}
}
*ranges = result;
}