paragraph_cache.hpp

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#pragma once

 
#ifdef PULP_HAS_SKIA
 
#include <cstddef>
#include <cstdint>
#include <functional>
#include <string_view>
 
namespace pulp::canvas {
 
class ParagraphCache {
  public:
    static ParagraphCache& instance();
 
    struct Stats {
        std::uint64_t hits = 0;            
        std::uint64_t builds = 0;          
        std::uint64_t evictions = 0;       
        std::uint64_t invalidations = 0;   
        std::size_t entries = 0;           
        std::size_t protected_entries = 0; 
        std::size_t bytes = 0;             
        std::size_t max_entries = 0;
        std::size_t max_bytes = 0;
    };
    Stats stats() const;
    void reset_stats();

    void clear();

    void set_enabled(bool enabled);
    bool enabled() const;

    void set_limits(std::size_t max_entries, std::size_t max_bytes);

    using BuildObserver = std::function<void(std::string_view text)>;
    void set_build_observer(BuildObserver observer);

    static std::size_t estimated_entry_bytes(std::size_t text_bytes) noexcept;
 
    // About 1000 short labels fill 16 MiB, so the two bounds bind for short and
    // long text respectively.
    static constexpr std::size_t kDefaultMaxEntries = 1024;
    static constexpr std::size_t kDefaultMaxBytes = 16u * 1024u * 1024u;
 
  private:
    ParagraphCache() = default;
};
 
} // namespace pulp::canvas
 
#endif // PULP_HAS_SKIA