/
collections.go
83 lines (71 loc) · 1.87 KB
/
collections.go
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/*
This file is part of Tessernote.
Tessernote is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
Tessernote 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with Tessernote. If not, see <http://www.gnu.org/licenses/>.
*/
package tessernote
import (
"appengine/datastore"
)
// addKey appends add to keys if add doesn't already exist in keys
func addKey(keys []*datastore.Key, add *datastore.Key) []*datastore.Key {
if !containsKey(keys, add) {
keys = append(keys, add)
}
return keys
}
// removeKey removes remove from keys
func removeKey(keys []*datastore.Key, remove *datastore.Key) []*datastore.Key {
i := indexOfKey(keys, remove)
if i >= 0 {
copy(keys[i:], keys[i+1:])
keys[len(keys)-1] = nil
return keys[:len(keys)-1]
}
return keys
}
func containsKey(keys []*datastore.Key, key *datastore.Key) bool {
return indexOfKey(keys, key) >= 0
}
func indexOfKey(keys []*datastore.Key, key *datastore.Key) int {
for i := range keys {
if keys[i].Encode() == key.Encode() {
return i
}
}
return -1
}
func containsString(strings []string, s string) bool {
for _, elem := range strings {
if elem == s {
return true
}
}
return false
}
func indexOfTag(tags []Tag, name string) int {
for i, tag := range tags {
if tag.Name == name {
return i
}
}
return -1
}
func unionKeys(a, b []*datastore.Key) []*datastore.Key {
c := *new([]*datastore.Key)
for _, elem := range a {
j := indexOfKey(b, elem)
if j >= 0 {
c = append(c, b[j])
}
}
return c
}