code.grnet.gr Git - pithos-ms-client/blob - trunk/Pithos.Client.WPF/Utils/EnumerableExtensions.cs

   1 using System;
   2 using System.Collections;
   3 using System.Collections.Generic;
   4 using System.IO;
   5 using System.Linq;
   6 using System.Linq.Expressions;
   7 using System.Text;
   8 using System.Text.RegularExpressions;
   9 using Pithos.Client.WPF.SelectiveSynch;
  10 using Pithos.Core;
  11 using Pithos.Interfaces;
  12
  13 namespace Pithos.Client.WPF.Utils
  14 {
  15     public static class EnumerableExtensions
  16     {
  17         public static IEnumerable<T> Slice<T>(this IEnumerable<T> collection, int start, int end)
  18         {
  19             int index = 0;
  20             int count = 0;
  21
  22             if (collection == null)
  23                 throw new ArgumentNullException("collection");
  24
  25             // Optimise item count for ICollection interfaces.
  26             if (collection is ICollection<T>)
  27                 count = ((ICollection<T>)collection).Count;
  28             else if (collection is ICollection)
  29                 count = ((ICollection)collection).Count;
  30             else
  31             {
  32                 count = collection.Count();
  33             }
  34
  35             // Get start/end indexes, negative numbers start at the end of the collection.
  36             if (start < 0)
  37                 start += count;
  38
  39             if (end < 0)
  40                 end += count;
  41
  42             foreach (var item in collection)
  43             {
  44                 if (index >= end)
  45                     yield break;
  46
  47                 if (index >= start)
  48                     yield return item;
  49
  50                 ++index;
  51             }
  52         }
  53
  54         public static IEnumerable<Node<T>> ToTree<TSource,T>(this IEnumerable<TSource> enumerable,Func<TSource,string> pathFunc,Func<TSource,T> valueFunc,string delimiter="/")
  55         {
  56             var orderedItems=enumerable.OrderBy(pathFunc);
  57             var lookups = new Dictionary<string,Node<T>>();
  58             var nodes = new List<Node<T>>();
  59             foreach (var item in orderedItems)
  60             {
  61                 var path = pathFunc(item);
  62                 var value = valueFunc(item);
  63                 var newNode = new Node<T> { Path = path,Data=value };
  64                 lookups[path] = newNode;
  65
  66                 var lastIndex = path.LastIndexOf(delimiter, StringComparison.Ordinal);
  67                 var upTo = lastIndex < 0 ? path.Length - 1 : lastIndex;
  68                 var parentPath = path.Substring(0, upTo);
  69
  70                 Node<T> parent;
  71                 if (lookups.TryGetValue(parentPath, out parent))
  72                 {
  73                     parent.Children.Add(newNode);
  74                     parent.Children.Sort((x,y)=>String.CompareOrdinal(x.Path, y.Path));
  75                 }
  76                 else
  77                     nodes.Add(newNode);
  78
  79             }
  80             return nodes;
  81         }
  82
  83
  84
  85
  86         static readonly Regex PascalCaseRegex = new Regex("[a-z][A-Z]", RegexOptions.Compiled);
  87         public static string Name(this  Enum value)
  88         {
  89             var name = Enum.GetName(value.GetType(), value);
  90             return PascalCaseRegex.Replace(name, m => m.Value[0] + " " + char.ToLower(m.Value[1]));
  91         }
  92     }
  93 }