//ranges == expression.Ranges
public void Loop(CharSetExpression expression, FlatSet <CharRange> ranges, NormalizedCharSet target)
{
if (expression.IsReverse)
{
char begin = (char)(char.MinValue + 1);
foreach (var r in ranges)
{
if (r.Begin > begin)
{
Process(expression, target, new CharRange(begin, (char)(r.Begin - 1)));
}
begin = (char)(r.End + 1);
}
if (begin <= char.MaxValue)
{
Process(expression, target, new CharRange(begin, char.MaxValue));
}
}
else
{
foreach (var r in ranges)
{
Process(expression, target, r);
}
}
}
public override void Process(CharSetExpression expression, NormalizedCharSet target, CharRange range)
{
int index = 0;
while (index < target.Ranges.Count)
{
var cur = target.Ranges[index];
var ranges = target.Ranges;
if (!cur.IsOverlapped(range))
{
index++;
continue;
}
else if (cur.Begin < range.Begin)
{
//cur: |---------|
//range: |---------?
//切割成两半
//插入两半后，index 自增后演变成：
//cur: |--|-------|
//range: |---------?
ranges.RemoveAt(index);
target.AddRange(cur.Begin, (char)(range.Begin - 1));
target.AddRange(range.Begin, cur.End);
index++;
}
else if (cur.Begin > range.Begin)
{
//cur: |----|
//range: |---------?
target.AddRange(range.Begin, (char)(cur.Begin - 1));
range.Begin = cur.Begin;
index++;
}
else if (cur.End < range.End)
{
//cur: |----|
//range: |---------|
range.Begin = (char)(cur.End + 1);
index++;
}
else if (cur.End > range.End)
{
//cur: |-----------|
//range: |---------|
target.Ranges.RemoveAt(index);
target.Ranges.Add(range);
target.AddRange((char)(range.End + 1), cur.End);
return;
}
else
{
return;
}
}
target.Ranges.Add(range);
}
public override bool Apply(CharSetExpression expression, NormalizedCharSet param)
{
var source = new FlatSet <CharRange>(expression.Ranges);
expression.Ranges.Clear();
Loop(expression, source, param);
expression.IsReverse = false;
return(false);
}
public override void Process(CharSetExpression expression, NormalizedCharSet target, CharRange range)
{
foreach (var r in target.Ranges)
{
if (range.Begin <= r.Begin && r.End <= range.End)
{
expression.Ranges.Add(r);
}
}
}
public abstract void Process(CharSetExpression expression, NormalizedCharSet target, CharRange range);
public override bool Apply(CharSetExpression expression, NormalizedCharSet target)
{
Loop(expression, expression.Ranges, target);
return(false);
}
