/
distinct_value_collector.go
80 lines (67 loc) · 2.15 KB
/
distinct_value_collector.go
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/*
* Copyright (C) 2023 Intergral GmbH
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <https://www.gnu.org/licenses/>.
*/
package util
type DistinctValueCollector[T comparable] struct {
values map[T]struct{}
len func(T) int
maxLen int
currLen int
totalLen int
}
// NewDistinctStringCollector with the given maximum data size. This is calculated
// as the total length of the recorded strings. For ease of use, maximum=0
// is interpreted as unlimited.
func NewDistinctValueCollector[T comparable](maxDataSize int, len func(T) int) *DistinctValueCollector[T] {
return &DistinctValueCollector[T]{
values: make(map[T]struct{}),
maxLen: maxDataSize,
len: len,
}
}
func (d *DistinctValueCollector[T]) Collect(v T) (exceeded bool) {
if _, ok := d.values[v]; ok {
// Already present
return
}
len := d.len(v)
// Record total inspected length regardless
d.totalLen += len
// Can it fit?
if d.maxLen > 0 && d.currLen+len > d.maxLen {
// No
return true
}
d.values[v] = struct{}{}
d.currLen += len
return false
}
// Strings returns the final list of distinct values collected and sorted.
func (d *DistinctValueCollector[T]) Values() []T {
ss := make([]T, 0, len(d.values))
for k := range d.values {
ss = append(ss, k)
}
return ss
}
// Exceeded indicates if some values were lost because the maximum size limit was met.
func (d *DistinctValueCollector[T]) Exceeded() bool {
return d.totalLen > d.currLen
}
// TotalDataSize is the total size of all distinct strings encountered.
func (d *DistinctValueCollector[T]) TotalDataSize() int {
return d.totalLen
}