1 files changed, 35 insertions, 0 deletions
diff --git a/src/util.c b/src/util.c
new file mode 100644
index 0000000..075c55c
--- /dev/null
+++ b/src/util.c
@@ -0,0 +1,35 @@
+#include <assert.h>
+
+#include "util.h"
+
+struct timespec timespec_diff(struct timespec a, struct timespec b)
+{
+    bool over = (b.tv_nsec - a.tv_nsec) < 0;
+    struct timespec diff = {
+        .tv_sec = b.tv_sec - a.tv_sec - over,
+        .tv_nsec = b.tv_nsec - a.tv_nsec + over * 1000000000ul,
+    };
+    return diff;
+}
+
+bool timespec_greater(struct timespec a, struct timespec b)
+{
+    return a.tv_sec > b.tv_sec
+        || (a.tv_sec == b.tv_sec && a.tv_nsec > b.tv_nsec);
+}
+
+bool in_capsule(int px, int py, int x, int y, int w, int h)
+{
+    assert(w >= h);
+    int radius = h / 2;
+
+    // Trivial case
+    if (w == h)
+        return in_circle(px, py, x + radius, y + radius, radius);
+
+    // General case
+    return in_circle(px, py, x + radius, y + radius, radius)
+        || in_circle(px, py, x + w - radius, y + radius, radius)
+        || in_rect(px, py, x + radius, y, w - 2 * radius, h);
+}
+