1 files changed, 72 insertions, 0 deletions
diff --git a/seqmatcher.cpp b/seqmatcher.cpp
new file mode 100644
index 0000000..f0abedc
--- /dev/null
+++ b/seqmatcher.cpp
@@ -0,0 +1,72 @@
+#include "seqmatcher.h"
+#include <cassert>
+
+
+SeqMatcher::SeqMatcher(Display *dpy) : dpy{dpy} {}
+
+SeqMatcher::SeqMatcher(Display *dpy, std::vector<SymSequence> seqs)
+		: dpy{dpy} {
+	for (const auto &seq : seqs) addSequence(seq.syms, seq.callback);
+}
+
+void SeqMatcher::addSequence(const std::vector<x::Keysym> &syms, Callback callback) {
+	if (syms.empty()) {
+		throw std::logic_error("Cannot register empty key sequence");
+	}
+
+	Node *current = &rootNode;
+	for (x::Keysym sym : syms) {
+		if (std::holds_alternative<Callback>(current->v)) {
+			throw std::logic_error("Overlapping key sequences (second is longer)");
+		} else {
+			if (!std::holds_alternative<NodeMap>(current->v)) {
+				current->v.emplace<NodeMap>();
+			}
+			NodeMap &map = std::get<NodeMap>(current->v);
+			x::Keycode code = sym.toCode(dpy);
+			auto it = map.find(code);
+			if (it != map.end()) {
+				current = it->second.get();
+			} else {
+				current = map.emplace(sym.toCode(dpy), std::make_unique<Node>()).first->second.get();
+			}
+		}
+	}
+
+	if (auto *map = std::get_if<NodeMap>(&current->v)) {
+		if (!map->empty()) {
+			throw std::logic_error("Overlapping key sequences (second is shorter)");
+		}
+	}
+	if (std::holds_alternative<Callback>(current->v)) {
+		throw std::logic_error("Overlapping key sequences (equally long)");
+	}
+	current->v.emplace<Callback>(callback);
+}
+
+std::optional<SeqMatcher::Callback> SeqMatcher::observe(const XKeyEvent &ev) {
+	auto *map = std::get_if<NodeMap>(&curNode->v);
+	assert(map);
+
+	auto it = map->find(x::Keycode{ev.keycode});
+	if (it == map->end()) {
+		// Sequence not found
+		reset();
+		return [dpy = dpy]() { x::bel(dpy); };
+	}
+
+	curNode = it->second.get();
+
+	if (auto *cb = std::get_if<Callback>(&curNode->v)) {
+		// Sequence completed
+		reset();
+		return *cb;
+	}
+
+	// Need more keys
+	return std::nullopt;
+}
+
+void SeqMatcher::reset() {
+	curNode = &rootNode;
+}