// Walk down the free list calling f() on the in-range portions, until
// f() returns true or we run out of free space. Return true iff f() returned true
func (s *Space) walkFree(r address.Range, f func(address.Range) bool) bool {
if r.Start >= r.End { // degenerate case
return false
}
for i := 0; i < len(s.free); i += 2 {
chunk := address.Range{Start: s.free[i], End: s.free[i+1]}
if chunk.End <= r.Start { // this chunk comes before the range
continue
}
if chunk.Start >= r.End {
// all remaining free space is completely after range
break
}
// at this point we know chunk.End>chunk.Start &&
// chunk.End>r.Start && r.End>chunk.Start && r.End>r.Start
// therefore max(start, r.Start) < min(end, r.End)
// Restrict this block of free space to be in range
if chunk.Start < r.Start {
chunk.Start = r.Start
}
if chunk.End > r.End {
chunk.End = r.End
}
// at this point we know start<end
if f(chunk) {
return true
}
}
return false
}
