public void Parse(StreamReader streamReader)
{
ParseState state = ParseState.Outside;
bool parseCancelled = false;
int depth = 0;
string buffer = streamReader.ReadToEnd();
char[] c = buffer.ToCharArray();
char attrQuoteChar = '\0';
int i = -1;
string elementName = "";
string attrName = "";
Dictionary <string, string> attributes = new Dictionary <string, string>();
bool documentStarted = false;
bool tokenComplete = false;
StringBuilder token = new StringBuilder();
while (++i < c.Length && !parseCancelled)
{
char cc = c[i]; // current char
switch (state)
{
case ParseState.Outside:
if (cc == '<')
{
documentStarted = true;
StartDocument?.Invoke();
state = ParseState.LessThan;
}
else
{
token.Append(cc);
}
break;
case ParseState.LessThan:
if (char.IsWhiteSpace(cc))
{
// do nothing
}
else if (MayStartXmlName(cc))
{
elementName = "";
attributes = new Dictionary <string, string>();
token = new StringBuilder(cc.ToString());
state = ParseState.NewElementName;
}
else if (cc == '/')
{
tokenComplete = false;
token = new StringBuilder();
state = ParseState.EndElementName;
}
else if (cc == '!') // !DOCTYPE or !CDATA[[ or !--
{
var bang = new string(c.SubArray(i, 10));
if (bang.StartsWith("!DOCTYPE "))
{
i += 8;
token = new StringBuilder();
state = ParseState.DocType;
}
else if (bang.StartsWith("!CDATA[["))
{
i += 7;
token = new StringBuilder();
state = ParseState.CData;
}
else if (bang.StartsWith("!--"))
{
i += 2;
token = new StringBuilder();
state = ParseState.Comment;
}
else
{
parseCancelled = RaiseError("Unexpected chars after <! : <" + c.SubArray(i, 5), i);
}
}
else if (cc == '?') // ?xml declaration ?
{
if (new string(c.SubArray(i, 5)) == "?xml ")
{
i += 4;
state = ParseState.XmlDeclaration;
}
else
{
state = ParseState.ProcessingInstruction;
}
}
else
{
parseCancelled = RaiseError("Unexpected char '" + cc.ToString() + "' after <", i);
}
break;
case ParseState.DocType:
case ParseState.XmlDeclaration:
if (cc == '>')
{
state = ParseState.Outside;
}
// Ignore anything else, until we get to '>'
break;
case ParseState.NewElementName:
if (ValidInXmlName(cc))
{
token.Append(cc);
}
else if (cc == '>')
{
elementName = token.ToString();
StartElement?.Invoke(elementName, attributes);
depth++;
token = new StringBuilder();
state = ParseState.InsideElement;
}
else if (cc == '/')
{
elementName = token.ToString();
state = ParseState.EmptyElement;
}
else if (cc == ' ')
{
elementName = token.ToString();
state = ParseState.SeekingAttrName;
attributes = new Dictionary <string, string>();
}
else
{
parseCancelled = RaiseError("Invalid char '" + cc.ToString() + "' in Element Name", i);
}
break;
case ParseState.SeekingAttrName:
if (char.IsWhiteSpace(cc))
{
// do nothing
}
else if (MayStartXmlName(cc))
{
token = new StringBuilder(cc.ToString());
state = ParseState.AttrName;
}
else if (cc == '/')
{
state = ParseState.EmptyElement;
}
else if (cc == '>')
{
StartElement?.Invoke(elementName, attributes);
depth++;
token = new StringBuilder();
state = ParseState.InsideElement;
}
else
{
parseCancelled = RaiseError("Invalid char '" + cc.ToString() + "' at start of Attribute Name", i);
}
break;
case ParseState.AttrName:
if (ValidInXmlName(cc))
{
token.Append(cc);
}
else if (cc == ' ')
{
attrName = token.ToString();
token = new StringBuilder();
state = ParseState.SeekingEquals;
}
else if (cc == '=')
{
attrName = token.ToString();
token = new StringBuilder();
state = ParseState.SeekingAttrValue;
}
else
{
parseCancelled = RaiseError("Invalid char '" + cc.ToString() + "' in Attribute Name", i);
}
break;
case ParseState.SeekingEquals:
if (cc == '=')
{
state = ParseState.SeekingAttrValue;
}
else if (cc == '/')
{
attributes.Add(attrName, "");
state = ParseState.EmptyElement;
}
else if (cc == '>')
{
attributes.Add(attrName, "");
token = new StringBuilder();
state = ParseState.InsideElement;
}
else if (MayStartXmlName(cc))
{
// Assume empty attribute (with no value)
attributes.Add(attrName, "");
token = new StringBuilder(cc.ToString());
state = ParseState.AttrName;
}
else
{
parseCancelled = RaiseError("Found '" + cc.ToString() + "' when expecting '=' after Attribute Name", i);
}
break;
case ParseState.SeekingAttrValue:
if (cc == '\'' || cc == '\"')
{
attrQuoteChar = cc;
token = new StringBuilder();
state = ParseState.AttrValue;
}
else
{
parseCancelled = RaiseError("Found '" + cc.ToString() + "' when expecting quoted Attribute Value", i);
}
break;
case ParseState.AttrValue:
if (cc == attrQuoteChar)
{
attributes.Add(attrName, token.ToString());
token = new StringBuilder();
state = ParseState.SeekingAttrName;
}
else
{
token.Append(cc);
}
break;
case ParseState.EmptyElement:
if (cc == '>')
{
StartElement?.Invoke(elementName, attributes);
// no change to depth, because...
EndElement?.Invoke(elementName);
token = new StringBuilder();
state = ParseState.InsideElement;
}
else if (cc == ' ')
{
// do nothing
}
else
{
parseCancelled = RaiseError("Found '" + cc.ToString() + "' after '/' in empty Element Tag", i);
}
break;
case ParseState.InsideElement:
if (cc == '<')
{
string data = token.ToString();
if (data.Length > 0)
{
if (string.IsNullOrWhiteSpace(data))
{
IgnorableWhitespace?.Invoke(data, 0, data.Length);
}
else
{
Characters?.Invoke(data, 0, data.Length);
}
}
token = new StringBuilder();
state = ParseState.LessThan;
}
else
{
token.Append(cc);
}
break;
case ParseState.EndElementName:
if (MayStartXmlName(cc) && token.Length == 0)
{
token.Append(cc);
tokenComplete = false;
}
else if (ValidInXmlName(cc) && !tokenComplete)
{
token.Append(cc);
}
else if (cc == '>')
{
elementName = token.ToString();
EndElement?.Invoke(elementName);
token = new StringBuilder();
if (--depth > 0)
{
state = ParseState.InsideElement;
}
else
{
state = ParseState.Outside;
}
}
else if (cc == ' ')
{
tokenComplete = true;
}
else
{
parseCancelled = RaiseError("Found '" + cc.ToString() + "' after Name in End-of-Element tag.", i);
}
break;
case ParseState.Comment:
if (cc == '-' && new string(c.SubArray(i, 3)) == "-->")
{
i += 2;
Comment?.Invoke(token.ToString());
token = new StringBuilder();
if (depth > 0)
{
state = ParseState.InsideElement;
}
else
{
state = ParseState.Outside;
}
}
else
{
token.Append(cc);
}
break;
case ParseState.ProcessingInstruction:
if (cc == '?' && new string(c.SubArray(i, 2)) == "?>")
{
i += 1;
elementName = token.ToString();
ProcessingInstruction?.Invoke(elementName.Head(), elementName.Tail());
token = new StringBuilder();
if (depth > 0)
{
state = ParseState.InsideElement;
}
else
{
state = ParseState.Outside;
}
}
else
{
token.Append(cc);
}
break;
default:
parseCancelled = RaiseError("Unhandled ParseState: " + state.ToString(), i);
break;
}
}
if (documentStarted)
{
EndDocument?.Invoke();
}
}
