/// <summary>
/// 分析样式的值，分解出其中的表达式和参数部分
/// </summary>
/// <param name="styleValue"></param>
/// <returns></returns>
public static HtmlStyleValueExpression ParseValue(string styleValue)
{
HtmlStyleValueExpression result = new HtmlStyleValueExpression();
result.Expression = styleValue;
if (styleValue.IsNotEmpty())
{
using (HtmlStyleValueParserContext context = new HtmlStyleValueParserContext())
{
while (context.Index < styleValue.Length)
{
switch (context.Stage)
{
case HtmlStyleValueParsingStage.None:
{
if (SkipNotLetterAndDigit(context, styleValue))
{
context.Stage = HtmlStyleValueParsingStage.ExpressionStage;
}
break;
}
case HtmlStyleValueParsingStage.ExpressionStage:
{
if (styleValue[context.Index] != '(')
{
context.Writer.Write(styleValue[context.Index++]);
}
else
{
context.ParenthesesLevel++;
result.Expression = context.ChangeStage(HtmlStyleValueParsingStage.ValueStage);
context.Index++;
}
break;
}
case HtmlStyleValueParsingStage.ValueStage:
{
if (styleValue[context.Index] != ')')
{
context.Writer.Write(styleValue[context.Index++]);
}
else
{
context.ParenthesesLevel--;
if (context.ParenthesesLevel == 0)
{
result.Value = context.ChangeStage(HtmlStyleValueParsingStage.None);
}
context.Index++;
}
break;
}
}
}
DoStyleValuePostOperation(context, result);
}
}
return(result);
}
private static HtmlStyleValueExpression DoStyleValuePostOperation(HtmlStyleValueParserContext context, HtmlStyleValueExpression styleExpression)
{
if (styleExpression != null)
{
switch (context.Stage)
{
case HtmlStyleValueParsingStage.ExpressionStage:
styleExpression.Expression = context.ChangeStage(HtmlStyleValueParsingStage.None);
break;
case HtmlStyleValueParsingStage.ValueStage:
styleExpression.Value = context.ChangeStage(HtmlStyleValueParsingStage.None);
break;
}
}
return(styleExpression);
}