#1589 Code simplify 202607

[Zufu Liu]

Range::Length() and SelectionRange::Length() can be simplified to use std::abs() on the distance.

[Zufu Liu]

Range::ContainsCharacter() and SelectionRange::ContainsCharacter(Sci::Position posCharacter) can be simplified to unreadable ((pos - start) * (pos - end)) < 0 or ((pos - start) ^ (pos - end)) < 0.

[Neil Hodgson]

Not worth the weirdness. The multiply version may overflow on huge documents.

[Zufu Liu]

Yeah, both may introduce new UB when either number is PTRDIFF_MIN, https://alive2.llvm.org/ce/z/4eA5gv

[Neil Hodgson]

Committed with [dea670] and [230a0b].

[Zufu Liu]

It might worth to bring back old manually expanded code for SelectionPosition::operator <= and operator >= (used by Contains() and ContainsCharacter()), Clang and MSVC seems honor other == *this and think that's the likely case, then do a literal compile, result in four comparisons instead of just two, see https://godbolt.org/z/qnvePMaYh

direct expansion with virtualSpace comparison merged:

bool SelectionPosition::operator <=(const SelectionPosition &other) const noexcept {
    if (position == other.position) {
        return virtualSpace <= other.virtualSpace;
    }
    return position < other.position;
}

bool SelectionPosition::operator >=(const SelectionPosition &other) const noexcept {
    if (position == other.position) {
        return virtualSpace >= other.virtualSpace;
    }
    return position > other.position;
}

or equivalents that MSVC generate small code. also looks close to operator < and operator > with just compare operator replaced.

bool SelectionPosition::operator <=(const SelectionPosition &other) const noexcept {
    if (position == other.position) {
        return virtualSpace <= other.virtualSpace;
    }
    return position <= other.position;
}

bool SelectionPosition::operator >=(const SelectionPosition &other) const noexcept {
    if (position == other.position) {
        return virtualSpace >= other.virtualSpace;
    }
    return position >= other.position;
}

SelectionRange::Contains(Sci::Position pos) and SelectionRange::ContainsCharacter(Sci::Position posCharacter) seems can be simplified to if (anchor.Position() > caret.Position()) as virtualSpace isn't used for further comparison.