Method Validate

Source/cmList.cxx:352–382

  }

  bool Validate(std::size_t count) override
  {
    this->Start = this->NormalizeIndex(this->Start, count);
    this->Stop = this->NormalizeIndex(this->Stop, count);

    // Does stepping move us further from the end?
    if (this->Start > this->Stop) {
      throw transform_error(
        cmStrCat("sub-command TRANSFORM, selector FOR "
                 "expects <start> to be no greater than <stop> (",
                 this->Start, " > ", this->Stop, ')'));
    }

    // compute indexes
    auto size = (this->Stop - this->Start + 1) / this->Step;
    if ((this->Stop - this->Start + 1) % this->Step != 0) {
      size += 1;
    }

    this->Indexes.resize(size);
    auto start = this->Start;
    auto step = this->Step;
    std::generate(this->Indexes.begin(), this->Indexes.end(),
                  [&start, step]() -> index_type {
                    auto r = start;
                    start += step;
                    return r;
                  });

    return true;
  }

private:
  index_type Start, Stop, Step;