53 lines
1.6 KiB
C++
53 lines
1.6 KiB
C++
#ifndef PAGETEMPERATUREREGISTRY_H_
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#define PAGETEMPERATUREREGISTRY_H_
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#include "MemoryMappedFile.h"
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#include <inttypes.h>
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#include <stddef.h>
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#include <sys/types.h>
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#include <atomic>
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//A registry of the "hotness" of documents, meaning how well-liked they are, how often referenced
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//by credible news sites, how fresh it is, etc. The temperature is used for ranking search results.
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class PageTemperatureRegistry {
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MemoryMappedFile mmf[2];
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std::atomic<unsigned> active_index;
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ino_t stat_ino;
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time_t stat_mtime;
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unsigned min_temperature;
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unsigned max_temperature;
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unsigned temperature_range_for_scaling;
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unsigned default_temperature;
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double min_temperature_log;
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double max_temperature_log;
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double temperature_range_for_scaling_log;
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double default_temperature_log;
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unsigned query_page_temperature_internal(uint64_t docid) const;
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unsigned query_page_temperature_internal(uint64_t docid, unsigned raw_default) const;
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public:
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PageTemperatureRegistry()
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: active_index(0), stat_ino(0), stat_mtime(-1),
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min_temperature(0), max_temperature(10), default_temperature(5)
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{}
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~PageTemperatureRegistry() { unload(); }
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bool load();
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void unload();
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void reload_if_needed();
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bool query_page_temperature(uint64_t docid, double range_min, double range_max, double *temperature) const;
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double scale_temperature(double range_min, double range_max, unsigned raw_temperature) const;
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double query_default_page_temperature(double range_min, double range_max) const;
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bool empty() const { return mmf[active_index].size()==0; }
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};
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extern PageTemperatureRegistry g_pageTemperatureRegistry;
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#endif
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