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             {
  47                 var next = _reader.Read();
  48                 if (next <= 0)
  49                     return next;
  50                 if (unchecked((char)next) == '*')
  51                     hasStar = true;
  52                 else if (hasStar && unchecked((char)next) == '/')
  53                     return Peek(); //recursively call self for comments following comments
  54                 else
  55                     hasStar = false;
  56             }
  57         }
  58
  59         //skip comments
  60         //TODO unescape escaped sequences
  61         public override int Read()
  62         {
  63             if (_cache.Count > 0)
  64                 return _cache.Dequeue();
  65
  66             int p = _reader.Read();
  67             if (p <= 0)
  68                 return p;
  69             var c = unchecked((char)p);
  70             if (c != '/')
  71                 return p;
  72
  73             _cache.Enqueue(c);
  74             p = _reader.Read();
  75             if (p <= 0)
  76                 return _cache.Dequeue();
  77             c = unchecked((char)p);
  78             if (c != '*')
  79                 return _cache.Dequeue();
  80
  81             _cache.Clear();
  82             _reader.Read(); //consume the '*'
  83
  84             bool hasStar = false;
  85             while (true)
  86             {
  87                 var next = _reader.Read();
  88                 if (next <= 0)
  89                     return next;
  90                 if (unchecked((char)next) == '*')
  91                     hasStar = true;
  92                 else if (hasStar && unchecked((char)next) == '/')
  93                     return Read(); //recursively call self for comments following comments
  94                 else
  95                     hasStar = false;
  96             }
  97         }
  98     }
  99 }