1 files changed, 49 insertions, 0 deletions
diff --git a/algo1w4d1/ValidXML.cpp b/algo1w4d1/ValidXML.cpp
new file mode 100644
index 0000000..4629b43
--- /dev/null
+++ b/algo1w4d1/ValidXML.cpp
@@ -0,0 +1,49 @@
+#include "ValidXML.h"
+#include <iostream>
+
+ValidXML::ValidXML() {}
+ValidXML::~ValidXML() {}
+
+void ValidXML::tag_finished() {
+	if (_tag_is_closing) {
+		if (_tag_stack.size() == 0) {
+			_valid = false;
+			return;
+		}
+		if (_tag_name.compare(_tag_stack.pop()) != 0) _valid = false;
+	} else {
+		_tag_stack.push(_tag_name);
+	}
+
+	// reset tag parser state
+	_tag_name = "";
+	_tag_is_closing = false;
+	_parsing_tag = false;
+	_tag_counter = 0;
+}
+
+void ValidXML::parse(char input) {
+	if (!_valid) return; // invalid XML can never be valid again
+
+	if (!_parsing_tag) {
+		if (input == '<') _parsing_tag = true; // < starts tag
+		if (input == '>') _valid = false; // double tag close
+		return; // ignore text outside tags
+	} else {
+		if (input == '/') { // closing tag marker
+			if (_tag_counter == 0) _tag_is_closing = true; // only allowed directly after <
+			else _valid = false;
+			return; // prevent increment of tag counter
+		}
+		else if (input == '<') _valid = false; // double tag open
+		else if (input == '>') return tag_finished(); // > closes tag
+		else if (_tag_counter == _tag_name.size() && input != ' ') _tag_name += input; // name is content of tag until space
+
+		_tag_counter++;
+	}
+}
+
+bool ValidXML::input_valid() {
+	// if (_tag_stack.size() > 0) return false;
+	return _valid;
+}