text: // Copyright © 2015 Steve Francia <spf@spf13.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 mem
  
  import "sort"
  
  type DirMap map[string]*FileData
  
  func (m DirMap) Len() int           { return len(m) }
  func (m DirMap) Add(f *FileData)    { m[f.name] = f }
  func (m DirMap) Remove(f *FileData) { delete(m, f.name) }
  func (m DirMap) Files() (files []*FileData) {
  	for _, f := range m {
  		files = append(files, f)
  	}
  	sort.Sort(filesSorter(files))
  	return files
  }
  
  // implement sort.Interface for []*FileData
  type filesSorter []*FileData
  
  func (s filesSorter) Len() int           { return len(s) }
  func (s filesSorter) Swap(i, j int)      { s[i], s[j] = s[j], s[i] }
  func (s filesSorter) Less(i, j int) bool { return s[i].name < s[j].name }
  
  func (m DirMap) Names() (names []string) {
  	for x := range m {
  		names = append(names, x)
  	}
  	return names
  }
  