Add heap debug option, fix heap.

[lttng-modules.git] / lib / prio_heap / prio_heap.h

diff --git a/lib/prio_heap/prio_heap.h b/lib/prio_heap/prio_heap.h
index 12b1638f9d46592584fb1f7a62829604fd94b1ca..2b55adf2e68401ab7a66627fe35e8c4fa85a3104 100644 (file)
--- a/lib/prio_heap/prio_heap.h
+++ b/lib/prio_heap/prio_heap.h
@@ -4,8 +4,7 @@
 /*
  * prio_heap.h
  *
- * Static-sized priority heap containing pointers. Based on CLRS,
- * chapter 6.
+ * Priority heap containing pointers. Based on CLRS, chapter 6.
  *
  * Copyright 2011 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
  *
@@ -20,10 +19,23 @@
  * all copies or substantial portions of the Software.
  */
 
-/*
- * TODO:
- * implement struct ptr_head, heap_init, heap_free, heap_insert.
- */
+#include <linux/gfp.h>
+
+struct ptr_heap {
+       size_t len, alloc_len;
+       void **ptrs;
+       int (*gt)(void *a, void *b);
+       gfp_t gfpmask;
+};
+
+#ifdef DEBUG_HEAP
+void check_heap(const struct ptr_heap *heap);
+#else
+static inline
+void check_heap(const struct ptr_heap *heap)
+{
+}
+#endif
 
 /**
  * heap_maximum - return the largest element in the heap
@@ -34,9 +46,39 @@
  */
 static inline void *heap_maximum(const struct ptr_heap *heap)
 {
-       return heap->size ? heap->ptrs[0] : NULL;
+       check_heap(heap);
+       return heap->len ? heap->ptrs[0] : NULL;
 }
 
+/**
+ * heap_init - initialize the heap
+ * @heap: the heap to initialize
+ * @alloc_len: number of elements initially allocated
+ * @gfp: allocation flags
+ * @gt: function to compare the elements
+ *
+ * Returns -ENOMEM if out of memory.
+ */
+extern int heap_init(struct ptr_heap *heap,
+                    size_t alloc_len, gfp_t gfpmask,
+                    int gt(void *a, void *b));
+
+/**
+ * heap_free - free the heap
+ * @heap: the heap to free
+ */
+extern void heap_free(struct ptr_heap *heap);
+
+/**
+ * heap_insert - insert an element into the heap
+ * @heap: the heap to be operated on
+ * @p: the element to add
+ *
+ * Insert an element into the heap.
+ *
+ * Returns -ENOMEM if out of memory.
+ */
+extern int heap_insert(struct ptr_heap *heap, void *p);
 
 /**
  * heap_remove - remove the largest element from the heap
@@ -68,7 +110,7 @@ extern void *heap_cherrypick(struct ptr_heap *heap, void *p);
  * the heap is empty.
  *
  * This is the equivalent of calling heap_remove() and then heap_insert(), but
- * it only rebalances the heap once.
+ * it only rebalances the heap once. It never allocates memory.
  */
 extern void *heap_replace_max(struct ptr_heap *heap, void *p);