1 files changed, 76 insertions, 0 deletions
diff --git a/server/hand.cpp b/server/hand.cpp
new file mode 100644
index 0000000..393a6c0
--- /dev/null
+++ b/server/hand.cpp
@@ -0,0 +1,76 @@
+#include "hand.h"
+
+bool Hand::agari(const Tiles& tiles) {
+	return basic_format(tiles);
+}
+
+bool Hand::basic_format(const Tiles& tiles, bool pair_eaten) {
+	if(!tiles) {
+		return true; // All tiles eaten.
+	}
+	
+	if(!pair_eaten) {
+		if(Tiles rest = eat_pair(tiles)) {
+			if(basic_format(rest, true)) {
+				return true;
+			}
+		}
+	}
+	
+	if(tiles.size() < 3) {
+		return false;
+	}
+	
+	if(Tiles rest = eat_pon(tiles)) {
+		if(basic_format(rest, pair_eaten)) {
+			return true;
+		}
+	}
+	
+	if(Tiles rest = eat_chi(tiles)) {
+		return basic_format(rest, pair_eaten);
+	}
+	
+	return false;
+}
+
+Tiles Hand::eat_pair(Tiles tiles) {
+	if(tiles[0] == tiles[1]) {
+		tiles.erase(tiles.begin(), tiles.begin() + 2);
+		return tiles;
+	}
+	return Tiles();
+}
+
+Tiles Hand::eat_pon(Tiles tiles) {
+	if(tiles[0] == tiles[2]) {
+		tiles.erase(tiles.begin(), tiles.begin() + 3);
+		return tiles;
+	}
+	return Tiles();
+}
+
+Tiles Hand::eat_chi(Tiles tiles) {
+	Tile::Set set = tiles[0].get_set();
+	int num = tiles[0].get_num();
+	
+	if(set == Tile::Honor || num > 7) {
+		// Can't be chi-ed.
+		return Tiles();
+	}
+	
+	Tiles::iterator it1 = std::find(tiles.begin(), tiles.end(), Tile(set, num + 1));
+	if(it1 != tiles.end()) {
+		Tiles::iterator it2 = std::find(tiles.begin(), tiles.end(), Tile(set, num + 2));
+		if(it2 != tiles.end()) {
+			// We can eat a chi of tiles.
+			tiles.erase(it2);
+			tiles.erase(it1);
+			tiles.erase(tiles.begin());
+			return tiles;
+		}
+	}
+	return Tiles();
+}
+
+