Rename proto-palettes to color sets (copied from rsgbds)

src/gfx/color_set.cpp

@@ -0,0 +1,79 @@
+// SPDX-License-Identifier: MIT
+
+#include "gfx/color_set.hpp"
+
+#include <algorithm>
+
+#include "helpers.hpp"
+
+void ColorSet::add(uint16_t color) {
+	size_t i = 0;
+
+	// Seek the first slot greater than the new color
+	// (A linear search is better because we don't store the array size,
+	// and there are very few slots anyway)
+	while (_colorIndices[i] < color) {
+		++i;
+		if (i == _colorIndices.size()) {
+			// We reached the end of the array without finding the color, so it's a new one.
+			return;
+		}
+	}
+	// If we found it, great! Nothing else to do.
+	if (_colorIndices[i] == color) {
+		return;
+	}
+
+	// Swap entries until the end
+	while (_colorIndices[i] != UINT16_MAX) {
+		std::swap(_colorIndices[i], color);
+		++i;
+		if (i == _colorIndices.size()) {
+			// The set is full, but doesn't include the new color.
+			return;
+		}
+	}
+	// Write that last one into the new slot
+	_colorIndices[i] = color;
+}
+
+ColorSet::ComparisonResult ColorSet::compare(ColorSet const &other) const {
+	// This works because the sets are sorted numerically
+	assume(std::is_sorted(RANGE(_colorIndices)));
+	assume(std::is_sorted(RANGE(other._colorIndices)));
+
+	auto ours = _colorIndices.begin(), theirs = other._colorIndices.begin();
+	bool weBigger = true, theyBigger = true;
+
+	while (ours != end() && theirs != other.end()) {
+		if (*ours == *theirs) {
+			++ours;
+			++theirs;
+		} else if (*ours < *theirs) {
+			++ours;
+			theyBigger = false;
+		} else { // *ours > *theirs
+			++theirs;
+			weBigger = false;
+		}
+	}
+	weBigger &= theirs == other.end();
+	theyBigger &= ours == end();
+
+	return theyBigger ? THEY_BIGGER : (weBigger ? WE_BIGGER : NEITHER);
+}
+
+size_t ColorSet::size() const {
+	return std::distance(RANGE(*this));
+}
+
+bool ColorSet::empty() const {
+	return _colorIndices[0] == UINT16_MAX;
+}
+
+auto ColorSet::begin() const -> decltype(_colorIndices)::const_iterator {
+	return _colorIndices.begin();
+}
+auto ColorSet::end() const -> decltype(_colorIndices)::const_iterator {
+	return std::find(RANGE(_colorIndices), UINT16_MAX);
+}