src/Tizen.NUI/src/internal/XamlBinding/StyleSheets/CssReader.cs

   1 using System;
   2 using System.Collections.Generic;
   3 using System.IO;
   4
   5 namespace Tizen.NUI.StyleSheets
   6 {
   7     internal sealed class CssReader : TextReader
   8     {
   9         readonly TextReader _reader;
  10
  11         public CssReader(TextReader reader)
  12         {
  13             if (reader == null)
  14                 throw new ArgumentNullException(nameof(reader));
  15
  16             _reader = reader;
  17         }
  18
  19         readonly Queue<char> _cache = new Queue<char>();
  20
  21         //skip comments
  22         //TODO unescape escaped sequences
  23         public override int Peek()
  24         {
  25             if (_cache.Count > 0)
  26                 return _cache.Peek();
  27
  28             int p = _reader.Peek();
  29             if (p <= 0)
  30                 return p;
  31             if (unchecked((char)p) != '/')
  32                 return p;
  33
  34             _cache.Enqueue(unchecked((char)_reader.Read()));
  35             p = _reader.Peek();
  36             if (p <= 0)
  37                 return _cache.Peek();
  38             if (unchecked((char)p) != '*')
  39                 return _cache.Peek();
  40
  41             _cache.Clear();
  42             _reader.Read(); //consume the '*'
  43
  44             bool hasStar = false;
  45             while (true) {
  46                 var next = _reader.Read();
  47                 if (next <= 0)
  48                     return next;
  49                 if (unchecked((char)next) == '*')
  50                     hasStar = true;
  51                 else if (hasStar && unchecked((char)next) == '/')
  52                     return Peek(); //recursively call self for comments following comments
  53                 else
  54                     hasStar = false;
  55             }
  56         }
  57
  58         //skip comments
  59         //TODO unescape escaped sequences
  60         public override int Read()
  61         {
  62             if (_cache.Count > 0)
  63                 return _cache.Dequeue();
  64
  65             int p = _reader.Read();
  66             if (p <= 0)
  67                 return p;
  68             var c = unchecked((char)p);
  69             if (c != '/')
  70                 return p;
  71
  72             _cache.Enqueue(c);
  73             p = _reader.Read();
  74             if (p <= 0)
  75                 return _cache.Dequeue();
  76             c = unchecked((char)p);
  77             if (c != '*')
  78                 return _cache.Dequeue();
  79
  80             _cache.Clear();
  81             _reader.Read(); //consume the '*'
  82
  83             bool hasStar = false;
  84             while (true) {
  85                 var next = _reader.Read();
  86                 if (next <= 0)
  87                     return next;
  88                 if (unchecked((char)next) == '*')
  89                     hasStar = true;
  90                 else if (hasStar && unchecked((char)next) == '/')
  91                     return Read(); //recursively call self for comments following comments
  92                 else
  93                     hasStar = false;
  94             }
  95         }
  96     }
  97 }