featurebase/index/general.go

package index

import (
	"github.com/golang/groupcache/lru"
)

type General struct {
	bitmap_cache *lru.Cache
	db           string
	slice        int
	storage      Storage
}

func NewGeneral(db string, slice int, s Storage) *General {
	f := new(General)
	f.bitmap_cache = lru.New(10000)
	f.storage = s
	f.slice = slice
	f.db = db
	return f

}

func (f *General) Union(bitmaps []uint64) IBitmap {
	result := NewBitmap()
	for i, id := range bitmaps {
		bm := f.Get(id)
		if i == 0 {
			result = bm
		} else {
			result = Union(result, bm)
		}
	}
	return result
}

func (f *General) Intersect(bitmaps []uint64) IBitmap {
	result := NewBitmap()
	for i, id := range bitmaps {
		bm := f.Get(id)
		if i == 0 {
			result = bm
		} else {
			result = Intersection(result, bm)
		}
	}
	return result
}

func (f *General) Get(bitmap_id uint64) IBitmap {
	bm, ok := f.bitmap_cache.Get(bitmap_id)
	if ok {
		return bm.(*Bitmap)
	}
	bm = f.storage.Fetch(bitmap_id, f.db, f.slice)
	f.bitmap_cache.Add(bitmap_id, bm)
	return bm.(*Bitmap)
}