服务器端C#实现的CSS解析器_C#教程

复制代码 代码如下:

using System;
using System.Collections;
using System.Text;
using System.IO;
using System.Collections.Specialized;
using System.Text.RegularExpressions;
using System.Diagnostics;

namespace CSS
{
public class App
{
public static void Main(string[] args)
{
//初始化CSS解析器
CssDocument doc = new CssDocument();
//加载现有CSS文件
doc.Load(Directory.GetCurrentDirectory() + "/test.css");
//修改CSS
doc["body"].Attributes["font-size"] = "12px";
//保存CSS文件
doc.Save(Directory.GetCurrentDirectory() + "/a.css");
Console.Read();
}
}

public class CssParse
{
private string m_source;
private int m_idx;

public static bool IsWhiteSpace(char ch)
{
return( "\t\n\r ".IndexOf(ch) != -1 );
}

public void EatWhiteSpace()
{
while ( !Eof() )
{
if ( !IsWhiteSpace(GetCurrentChar()) )
return;
m_idx++;
}
}

public bool Eof()
{
return(m_idx>=m_source.Length );
}

public string ParseElementName()
{
StringBuilder element = new StringBuilder();
EatWhiteSpace();
while ( !Eof() )
{
if (GetCurrentChar()=='{')
{
m_idx++;
break;
}
element.Append(GetCurrentChar());
m_idx++;
}

EatWhiteSpace();
return element.ToString().Trim();
}

public string ParseAttributeName()
{
StringBuilder attribute = new StringBuilder();
EatWhiteSpace();

while ( !Eof() )
{
if (GetCurrentChar()==':')
{
m_idx++;
break;
}
attribute.Append(GetCurrentChar());
m_idx++;
}

EatWhiteSpace();
return attribute.ToString().Trim();
}

public string ParseAttributeValue()
{
StringBuilder attribute = new StringBuilder();
EatWhiteSpace();
while ( !Eof() )
{
if (GetCurrentChar()==';')
{
m_idx++;
break;
}
attribute.Append(GetCurrentChar());
m_idx++;
}

EatWhiteSpace();
return attribute.ToString().Trim();
}

public char GetCurrentChar()
{
return GetCurrentChar(0);
}

public char GetCurrentChar(int peek)
{
if( (m_idx+peek)<m_source.Length )
return m_source[m_idx+peek];
else
return (char)0;
}

public char AdvanceCurrentChar()
{
return m_source[m_idx++];
}

public void Advance()
{
m_idx++;
}

public string Source
{
get
{
return m_source;
}

set
{
m_source = value;
}
}

public ArrayList Parse()
{
ArrayList elements = new ArrayList();

while (!Eof())
{
string elementName = ParseElementName();

if (elementName == null)
break;

CssElement element = new CssElement(elementName);

string name = ParseAttributeName();
string value = ParseAttributeValue();

while (name != null && value != null)
{
element.Add(name, value);

EatWhiteSpace();

if (GetCurrentChar()=='}')
{
m_idx++;
break;
}

name = ParseAttributeName();
value = ParseAttributeValue();
}

elements.Add(element);
}

return elements;
}
}

public class CssDocument
{
private string _Text;
public string Text
{
get
{
return _Text;
}
set
{
_Text = value;
}
}

private ArrayList _Elements;
public ArrayList Elements
{
get
{
return _Elements;
}
set
{
_Elements = value;
}
}

public CssElement this[string name]
{
get
{
for (int i = 0; i < Elements.Count; i++)
{
if (((CssElement)Elements[i]).Name.Equals(name))
return (CssElement)Elements[i];
}

return null;
}
}

private string _File;
public string File
{
get
{
return _File;
}
set
{
_File = value;
}
}

public CssDocument()
{

}

public void Load(string file)
{
using (StreamReader sr = new StreamReader(file))
{
Text = sr.ReadToEnd();
sr.Close();
}

CssParse parse = new CssParse();
parse.Source = Regex.Replace(Text, @"/\*.*?\*/", "", RegexOptions.Compiled);
Elements = parse.Parse();

}

public void Add(CssElement element)
{
Elements.Add(element);
}

public void Save()
{
Save(this.File);
}

public void Save(string file)
{
using (StreamWriter sw = new StreamWriter(file, false))
{
for (int i = 0; i < Elements.Count; i++)
{
CssElement element = (CssElement)Elements[i];
sw.WriteLine(element.Name + " {");
foreach (string name in element.Attributes.AllKeys)
{
sw.WriteLine("\t{0}:{1};", name, element.Attributes[name]);
}
sw.WriteLine("}");
}
sw.Flush();
sw.Close();
}
}
}

public class CssElement
{
private string _Name;
public string Name
{
get
{
return _Name;
}
set
{
_Name = value;
}
}

private NameValueCollection _Attributes;
public NameValueCollection Attributes
{
get
{
return _Attributes;
}
set
{
_Attributes = value;
}
}

public CssElement(string name)
{
this.Name = name;
Attributes = new NameValueCollection();
}

public void Add(string attribute, string value)
{
Attributes[attribute] = value;
}
}
}