feat: add compareNodes and prioqInit

src/prioq.c

@@ -0,0 +1,55 @@
+#include "prioq.h"
+
+static int compareNodes(const RbtNode* a, const RbtNode* b)
+{
+    const PrioQNode* pa = rbtEntry(a, PrioQNode, node);
+    const PrioQNode* pb = rbtEntry(b, PrioQNode, node);
+
+    if (pa->vruntime != pb->vruntime)
+        return pa->vruntime < pb->vruntime ? -1 : 1;
+    if (pa->id != pb->id)
+        return pa->id < pb->id ? -1 : 1;
+    return 0;
+}
+
+void prioqInit(PrioQueue* q)
+{
+    rbtInit(&q->tree);
+}
+
+void prioqInsert(PrioQueue* q, PrioQNode* n, uint64 vruntime, uint32 id)
+{
+    n->vruntime = vruntime;
+    n->id = id;
+    bool inserted = rbtInsert(&q->tree, &n->node, compareNodes);
+    (void)inserted; /* unique id guarantees the key can never already exist */
+}
+
+PrioQNode* prioqPeekMin(const PrioQueue* q)
+{
+    RbtNode* n = rbtFirst(&q->tree);
+    return n ? rbtEntry(n, PrioQNode, node) : nullptr;
+}
+
+PrioQNode* prioqPopMin(PrioQueue* q)
+{
+    PrioQNode* min = prioqPeekMin(q);
+    if (min)
+        rbtRemove(&q->tree, &min->node);
+    return min;
+}
+
+void prioqRemove(PrioQueue* q, PrioQNode* n)
+{
+    rbtRemove(&q->tree, &n->node);
+}
+
+usize prioqCount(const PrioQueue* q)
+{
+    return rbtCount(&q->tree);
+}
+
+bool prioqIsEmpty(const PrioQueue* q)
+{
+    return rbtIsEmpty(&q->tree);
+}