public RepExpression(Expression expression, Expression?separator, RepCount count, MatchOrder order = MatchOrder.Greedy)
{
Expression = expression;
Separator = separator;
Count = count;
Order = order;
}
/// <summary>
/// 对一段字符串进行高频解析
/// </summary>
/// <param name="str">字符串</param>
/// <param name="index">字符串之前的偏移量</param>
/// <param name="offset">当前偏移量</param>
/// <returns></returns>
private List <RepeateModel> GetHighFrequency(string str, int index, int offset = 0, MatchOrder order = MatchOrder.None, string other = default)
{
List <RepeateModel> result = new List <RepeateModel>();
RepeateModel model = default;
if (str.Length < 3 || str.Length == 4)
{
model = GetFrequencyByOffsetAndIndex(str, index, str.Length);
model.StartIndex += offset;
result.Add(model);
}
else if (str.Length == 3)
{
// 3个字符分割成 2 + 1 分别求权值
int tempPriority1 = 0;
var model1 = GetFrequencyByOffsetAndIndex(str.Substring(0, 2), index, 2);
tempPriority1 += model1.MatchCount;
var model2 = GetFrequencyByOffsetAndIndex(str.Substring(2, 1), index + 2, 1);
tempPriority1 += model2.MatchCount;
//3个字符分割成 1 + 2 分别求权值
int tempPriority2 = 0;
var model3 = GetFrequencyByOffsetAndIndex(str.Substring(0, 1), index, 1);
tempPriority2 += model3.MatchCount;
var model4 = GetFrequencyByOffsetAndIndex(str.Substring(1, 2), index + 1, 2);
tempPriority2 += model4.MatchCount;
//3个字符借位求权
int tempPriority3 = 0;
if (order != MatchOrder.None)
{
model = GetFrequencyByOffsetAndIndex(other, index, 4);
tempPriority3 = model.MatchCount;
}
//匹配权比较
if (tempPriority1 >= tempPriority2)
{
if (tempPriority1 >= tempPriority3)
{
model1.StartIndex += offset;
result.Add(model1);
model2.StartIndex += offset + 2;
result.Add(model2);
}
else if (order == MatchOrder.RightToLeft)
{
model.StartIndex += offset - 1;
result.Add(model);
}
else if (order == MatchOrder.LeftToRight)
{
model.StartIndex += offset;
result.Add(model);
}
}
else
{
if (tempPriority2 >= tempPriority3)
{
model3.StartIndex += offset;
result.Add(model3);
model4.StartIndex += offset + 1;
result.Add(model4);
}
else if (order == MatchOrder.RightToLeft)
{
model.StartIndex += offset - 1;
result.Add(model);
}
else if (order == MatchOrder.LeftToRight)
{
model.StartIndex += offset;
result.Add(model);
}
}
}
else
{
//如果是4个或者4个以上的, 那么找到4个字符为一组的，匹配最多的那组
model = GetMaxFrequencyModel(str, index);
//如果该组左侧有字符，那么递归处理左侧字符
//如果获取的匹配节点的起点不在原点，证明左边是有剩余字符串的
if (model.StartIndex > 0)
{
//获取左边的字符
var source = str.Substring(0, model.StartIndex);
if (source.Length == 3)
{
result.AddRange(GetHighFrequency(source, index, offset, MatchOrder.LeftToRight, str.Substring(0, 4)));
}
else
{
result.AddRange(GetHighFrequency(source, index, offset));
}
}
//如果该组右侧有字符，那么递归处理右侧字符
if (model.StartIndex + 4 < str.Length)
{
int tempOffset = model.StartIndex + 4;
var source = str.Substring(model.StartIndex, str.Length - tempOffset);
if (source.Length == 3)
{
result.AddRange(GetHighFrequency(source, index + 4, tempOffset + offset, MatchOrder.RightToLeft, str.Substring(model.StartIndex + 3, 4)));
}
else
{
result.AddRange(GetHighFrequency(source, index + 4, tempOffset + offset));
}
}
model.StartIndex += offset;
result.Add(model);
}
return(result);
}
public OptExpression(Expression expression, MatchOrder order = MatchOrder.Greedy)
{
Expression = expression;
Order = order;
}