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elems.go
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elems.go
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package bptree
import (
"fmt"
"sort"
)
type Elems []Elem
func (elems Elems) Len() int { return len(elems) }
func (elems Elems) Less(i, j int) bool {
cond := elems[i].Key().CompareTo(elems[j].Key())
return cond == Less
}
func (elems Elems) Swap(i, j int) { elems[i], elems[j] = elems[j], elems[i] }
func (elems Elems) find(key Key) (idx int, isEqual bool) {
idx = sort.Search(len(elems), func(i int) bool {
cond := elems[i].Key().CompareTo(key)
if cond == Equal {
isEqual = true
}
return cond == Equal || cond == Greater
})
return
}
func (elems Elems) insert(elem Elem, maxDegree int, allowOverlap bool) (Elems, error) {
idx, equal := elems.find(elem.Key())
if idx >= len(elems) {
elems = append(elems, elem)
return elems, nil
}
if equal && !allowOverlap {
return nil, ERR_OVERLAPPED
}
newElems := make(Elems, len(elems)+1, maxDegree+1)
copy(newElems, elems[:idx])
newElems[idx] = elem
copy(newElems[idx+1:], elems[idx:])
return newElems, nil
}
func (elems Elems) delete(key Key, maxDegree int) (Elems, bool) {
idx, equal := elems.find(key)
if equal {
// found
newElems := make(Elems, len(elems)-1, maxDegree+1)
copy(newElems, elems[:idx])
copy(newElems[idx:], elems[idx+1:])
return newElems, true
}
return elems, false
}
func (elems Elems) String() string {
var elemsStr []string
for _, _elem := range elems {
switch elem := _elem.(type) {
case *indexNode:
elemsStr = append(elemsStr, fmt.Sprintf("i<%v>", elem.Key()))
default:
elemsStr = append(elemsStr, fmt.Sprintf("e<%v>", elem.Key()))
}
}
return fmt.Sprintf("%v", elemsStr)
}