Add maze pkg

pkg/maze/cell/cell.go

@@ -0,0 +1,21 @@
+// Package cell represents a single cell in a maze grid.
+package cell
+
+import (
+	"code.chimeric.al/dwrz/minotaur/pkg/maze/direction"
+)
+
+// Cell is a bitmask of open passages from a cell to its neighbors.
+// Bit d (1 << d) is 1 when the passage in direction d is open, and 0 when a
+// wall blocks that direction.
+type Cell uint8
+
+// HasDirection reports whether the passage in direction d is open.
+func (c Cell) HasDirection(d direction.Direction) bool {
+	return c&(1<<d) != 0
+}
+
+// SetDirection opens the passage in direction d.
+func (c *Cell) SetDirection(d direction.Direction) {
+	*c |= 1 << d
+}

pkg/maze/cell/cell_test.go

@@ -0,0 +1,43 @@
+package cell
+
+import (
+	"testing"
+
+	"code.chimeric.al/dwrz/minotaur/pkg/maze/direction"
+)
+
+func TestSetDirection(t *testing.T) {
+	var c Cell
+	t.Logf("start: %08b", c)
+
+	c.SetDirection(direction.Right)
+	t.Logf("set right: %08b", c)
+
+	c.SetDirection(direction.Down)
+	t.Logf("set down: %08b", c)
+
+	var (
+		hasRight = c.HasDirection(direction.Right)
+		hasDown  = c.HasDirection(direction.Down)
+		hasLeft  = c.HasDirection(direction.Left)
+		hasUp    = c.HasDirection(direction.Up)
+	)
+
+	t.Logf("has right: %v", hasRight)
+	t.Logf("has down: %v", hasDown)
+	t.Logf("has left: %v", hasLeft)
+	t.Logf("has up: %v", hasUp)
+
+	if !hasRight {
+		t.Errorf("expected cell to have right")
+	}
+	if !hasDown {
+		t.Errorf("expected cell to have down")
+	}
+	if hasLeft {
+		t.Errorf("expected cell to not have left")
+	}
+	if hasUp {
+		t.Errorf("expected cell to not have up")
+	}
+}