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Avoid reusing a static local variable (too fragile)

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Rangi42
2025-10-08 21:19:23 -04:00
parent 26c48cc409
commit 651877e094
1 changed files with 18 additions and 21 deletions
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39
src/gfx/pal_packing.cpp
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@@ -177,27 +177,31 @@ private:
}
}
// This function should stay private because it returns a reference to a unique object
std::unordered_set<uint16_t> &uniqueColors() const {
// We check for *distinct* colors by stuffing them into a `set`; this should be
// faster than "back-checking" on every element (O(n^2))
static std::unordered_set<uint16_t> colors;
colors.clear();
public:
// Returns the set of distinct colors
std::unordered_set<uint16_t> uniqueColors() const {
std::unordered_set<uint16_t> colors;
addUniqueColors(colors, RANGE(*this), *_colorSets);
return colors;
}
public:
// Returns the number of distinct colors
size_t volume() const { return uniqueColors().size(); }
bool canFit(ColorSet const &colorSet) const {
std::unordered_set<uint16_t> &colors = uniqueColors();
std::unordered_set<uint16_t> colors = uniqueColors();
colors.insert(RANGE(colorSet));
return colors.size() <= options.maxOpaqueColors();
}
// Counts how many of our color sets this color also belongs to
uint32_t multiplicity(uint16_t color) const {
return std::count_if(RANGE(*this), [this, &color](ColorSetAttrs const &attrs) {
ColorSet const &pal = (*_colorSets)[attrs.colorSetIndex];
return std::find(RANGE(pal), color) != pal.end();
});
}
// The `relSizeOf` method below should compute the sum, for each color in `colorSet`, of
// the reciprocal of the "multiplicity" of the color across "our" color sets.
// However, literally computing the reciprocals would involve floating-point division, which
@@ -217,24 +221,17 @@ public:
// Computes the "relative size" of a color set on this palette;
// it's a measure of how much this color set would "cost" to introduce.
uint32_t relSizeOf(ColorSet const &colorSet) const {
// NOTE: this function must not call `uniqueColors`, or one of its callers will break!
uint32_t relSize = 0;
for (uint16_t color : colorSet) {
// How many of our color sets does this color also belong to?
uint32_t multiplicity =
std::count_if(RANGE(*this), [this, &color](ColorSetAttrs const &attrs) {
ColorSet const &pal = (*_colorSets)[attrs.colorSetIndex];
return std::find(RANGE(pal), color) != pal.end();
});
uint32_t n = multiplicity(color);
// We increase the denominator by 1 here; the reference code does this,
// but the paper does not. Not adding 1 makes a multiplicity of 0 cause a division by 0
// (that is, if the color is not found in any color set), and adding 1 still seems
// to preserve the paper's reasoning.
//
// The scale factor should ensure integer divisions only.
assume(scaleFactor % (multiplicity + 1) == 0);
relSize += scaleFactor / (multiplicity + 1);
assume(scaleFactor % (n + 1) == 0);
relSize += scaleFactor / (n + 1);
}
return relSize;
}
@@ -244,7 +241,7 @@ public:
size_t combinedVolume(
IteratorT &&begin, IteratorT const &end, std::vector<ColorSet> const &colorSets
) const {
std::unordered_set<uint16_t> &colors = uniqueColors();
std::unordered_set<uint16_t> colors = uniqueColors();
addUniqueColors(colors, std::forward<IteratorT>(begin), end, colorSets);
return colors.size();
}
@@ -252,7 +249,7 @@ public:
// Computes the "relative size" of a set of colors on this palette
template<typename IteratorT>
size_t combinedVolume(IteratorT &&begin, IteratorT &&end) const {
std::unordered_set<uint16_t> &colors = uniqueColors();
std::unordered_set<uint16_t> colors = uniqueColors();
colors.insert(std::forward<IteratorT>(begin), std::forward<IteratorT>(end));
return colors.size();
}