feat(data): SPSC ring buffer, incremental min/max LOD pyramid, series types

include/plot/data/array_series.hpp

@@ -0,0 +1,43 @@
+#pragma once
+#include <vector>
+
+#include <plot/core/types.hpp>
+#include <plot/data/series.hpp>
+
+namespace plot::data {
+
+/// Series over a uniform-dx sample vector.
+///
+/// The vector is taken by value and owned from then on, so the caller cannot
+/// mutate the samples behind the series' back; the store changes only through
+/// reset() (a whole new vector) or commit(), which rebuilds the pyramid and the
+/// cached bounds for whatever y_ currently holds.
+class ArraySeries final : public Series {
+ public:
+  ArraySeries(std::vector<f32> y, f64 x0, f64 dx);
+  /// Replaces samples and grid, then rebuilds derived state (== commit()).
+  void reset(std::vector<f32> y, f64 x0, f64 dx);
+  /// Rebuilds the pyramid and cached bounds from y_ as it stands now.
+  void commit();
+
+  u64 size() const override;
+  f64 x0() const override;
+  f64 dx() const override;
+  Range x_bounds() const override;
+  Range y_bounds() const override;
+  const MinMaxPyramid& pyramid() const override;
+  void gather(u32 level, u64 begin, u64 end, std::vector<f32>& out_xy) const override;
+
+ protected:
+  void copy_raw(u64 begin, u64 end, f32* out) const override;
+
+ private:
+  std::vector<f32> y_;
+  f64 x0_ = 0.0;
+  f64 dx_ = 1.0;
+  MinMaxPyramid pyramid_;
+  Range x_bounds_{};
+  Range y_bounds_{};
+};
+
+}  // namespace plot::data