| 1 | // Package readcoord tracks what a read actually delivered and decides whether |
| 2 | // a read requirement is met. It is host-only: it renders nothing, mutates no |
| 3 | // file, and never changes provider bytes. |
| 4 | package readcoord |
| 5 | |
| 6 | import ( |
| 7 | "slices" |
| 8 | |
| 9 | "reasonix/internal/tool" |
| 10 | ) |
| 11 | |
| 12 | // Normalize drops empty ranges and merges overlaps and adjacency into the |
| 13 | // smallest equivalent set. |
| 14 | func Normalize(ranges []tool.ReadRange) []tool.ReadRange { |
| 15 | out := make([]tool.ReadRange, 0, len(ranges)) |
| 16 | for _, r := range ranges { |
| 17 | if !r.Empty() { |
| 18 | out = append(out, r) |
| 19 | } |
| 20 | } |
| 21 | if len(out) == 0 { |
| 22 | return nil |
| 23 | } |
| 24 | slices.SortFunc(out, func(a, b tool.ReadRange) int { |
| 25 | if a.Start != b.Start { |
| 26 | return a.Start - b.Start |
| 27 | } |
| 28 | return a.End - b.End |
| 29 | }) |
| 30 | merged := out[:1] |
| 31 | for _, r := range out[1:] { |
| 32 | last := &merged[len(merged)-1] |
| 33 | if r.Start <= last.End { |
| 34 | last.End = max(last.End, r.End) |
| 35 | continue |
| 36 | } |
| 37 | merged = append(merged, r) |
| 38 | } |
| 39 | return merged |
| 40 | } |
| 41 | |
| 42 | // Subtract returns the parts of want that have does not cover. |
| 43 | func Subtract(want, have []tool.ReadRange) []tool.ReadRange { |
| 44 | have = Normalize(have) |
| 45 | var out []tool.ReadRange |
| 46 | for _, w := range Normalize(want) { |
| 47 | cur := w |
| 48 | for _, h := range have { |
| 49 | if h.End <= cur.Start { |
| 50 | continue |
| 51 | } |
| 52 | if h.Start >= cur.End { |
| 53 | break |
| 54 | } |
| 55 | if h.Start > cur.Start { |
| 56 | out = append(out, tool.ReadRange{Start: cur.Start, End: h.Start}) |
| 57 | } |
| 58 | cur.Start = max(cur.Start, h.End) |
| 59 | if cur.Empty() { |
| 60 | break |
| 61 | } |
| 62 | } |
| 63 | if !cur.Empty() { |
| 64 | out = append(out, cur) |
| 65 | } |
| 66 | } |
| 67 | return out |
| 68 | } |
| 69 | |
| 70 | // Covers reports whether have covers every line of want. |
| 71 | func Covers(have, want []tool.ReadRange) bool { |
| 72 | return len(Subtract(want, have)) == 0 |
| 73 | } |
| 74 |