/
database.go
104 lines (92 loc) · 2.41 KB
/
database.go
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// Copyright 2015 Davy Wybiral <davy.wybiral@gmail.com>
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package staydb
import (
"github.com/RoaringBitmap/roaring"
)
type Database struct {
ids map[string]uint32
keys []string
columns map[string]*roaring.Bitmap
}
// Create and return a new empty database.
func NewDatabase() *Database {
return &Database{
ids: make(map[string]uint32),
keys: make([]string, 0),
columns: make(map[string]*roaring.Bitmap),
}
}
func (db *Database) Len() int {
return len(db.keys)
}
// Get the integer id of a key or create one if the key doesn't exist.
func (db *Database) getId(key string) uint32 {
id, ok := db.ids[key]
if !ok {
id = uint32(len(db.keys))
db.ids[key] = id
db.keys = append(db.keys, key)
}
return id
}
// Get *Column object by name or create one if it doesn't exist.
func (db *Database) getColumn(column string) *roaring.Bitmap {
col, ok := db.columns[column]
if !ok {
col = roaring.New()
db.columns[column] = col
}
return col
}
// Add "column" to "key".
func (db *Database) Add(key string, column string) {
id := db.getId(key)
col := db.getColumn(column)
col.Add(id)
}
// Remove "column" from "key".
func (db *Database) Remove(key string, column string) {
id := db.getId(key)
col := db.getColumn(column)
col.Remove(id)
}
// Return a Query over an entire column.
func (db *Database) Query(column string) *Query {
col, ok := db.columns[column]
if !ok {
return &Query{b: roaring.New(), n: len(db.keys)}
}
return &Query{b: col, n: len(db.keys)}
}
// Return resulting keys from a query.
func (db *Database) GetKeys(q *Query) chan string {
ch := make(chan string)
go func() {
itr := q.b.Iterator()
for itr.HasNext() {
ch <- db.keys[itr.Next()]
}
close(ch)
}()
return ch
}
// Return array of columns.
func (db *Database) Columns() []string {
out := make([]string, 0)
for column, _ := range db.columns {
out = append(out, column)
}
return out
}