範囲検索の実装テスト

gistfile1.txt

// リソースをRangeに変換
// 指定範囲をRangeに変換
// Range同士のANDを取る
interface ResourceRange {
  start: number;
  length: number;
}
function convertLengthToResourceRange(
  length: number[],
  start: number = 0
): ResourceRange[] {
  if (length.length === 0) {
    return [];
  }
  const ret: ResourceRange = { start: start, length: length[0] };
  return [ret].concat(
    convertLengthToResourceRange(length.splice(1), start + length[0])
  );
}
it("convertResourceLengthToRange", () => {
  const ret = convertLengthToResourceRange([10, 10, 10, 10, 10]);
  expect(ret[0]).toEqual({ start: 0, length: 10 });
  expect(ret[1]).toEqual({ start: 10, length: 10 });
  expect(ret[2]).toEqual({ start: 20, length: 10 });
  expect(ret[3]).toEqual({ start: 30, length: 10 });
  expect(ret[4]).toEqual({ start: 40, length: 10 });
});

function collition(a: ResourceRange, b: ResourceRange): ResourceRange | null {
  const startIndex = Math.max(a.start, b.start);
  const endIndex = Math.min(a.start + a.length, b.start + b.length);
  return startIndex < endIndex
    ? { start: startIndex, length: endIndex - startIndex }
    : null;
}

it("collition", () => {
  expect(
    collition({ start: 0, length: 10 }, { start: 0, length: 10 })
  ).toEqual({ start: 0, length: 10 });
  expect(
    collition({ start: 0, length: 10 }, { start: 5, length: 10 })
  ).toEqual({ start: 5, length: 5 });
  expect(
    collition({ start: 0, length: 10 }, { start: 10, length: 10 })
  ).toEqual(null);
  expect(
    collition({ start: 0, length: 10 }, { start: 15, length: 20 })
  ).toEqual(null);
});

it("hoge", () => {
  const selectRange = { start: 15, length: 20 };
  const ret = convertLengthToResourceRange([10, 10, 10, 10, 10]);
  const a = ret.map((range) => {
    return collition(range, selectRange);
  });
  expect(a[0]).toEqual(null);
  expect(a[1]).toEqual({ start: 15, length: 5 });
  expect(a[2]).toEqual({ start: 20, length: 10 });
  expect(a[3]).toEqual({ start: 30, length: 5 });
  expect(a[4]).toEqual(null);

  const b: (ResourceRange | null)[] = a.map((range, i) => {
    if (range == null) {
      return null;
    }
    return { start: range.start - ret[i].start, length: range.length };
  });
  expect(b[0]).toEqual(null);
  expect(b[1]).toEqual({ start: 5, length: 5 });
  expect(b[2]).toEqual({ start: 0, length: 10 });
  expect(b[3]).toEqual({ start: 0, length: 5 });
  expect(b[4]).toEqual(null);
});