Add custom pm sysmodule

sysmodules/pm/source/intrusive_list.h

@@ -0,0 +1,86 @@
+#pragma once
+
+#include <stddef.h>
+#include <stdbool.h>
+
+/// Intrusive node structure definition.
+typedef struct IntrusiveNode {
+    struct IntrusiveNode *prev; ///< Pointer to the previous node.
+    struct IntrusiveNode *next; ///< Pointer to the next node.
+} IntrusiveNode;
+
+/// Intrusive list structure definition.
+typedef union IntrusiveList {
+    IntrusiveNode node;
+    struct {
+        IntrusiveNode *last;     ///< Pointer to the last element.
+        IntrusiveNode *first;    ///< Pointer to the first element.
+    };
+} IntrusiveList;
+
+/**
+ * @brief Initializes the intrusive linked list.
+ *
+ * @param ll The intrusive list to initialize.
+ */
+static inline void IntrusiveList_Init(IntrusiveList *ll)
+{
+    ll->node.prev = &ll->node;
+    ll->node.next = &ll->node;
+}
+
+/**
+ * @brief Tests if a node is past the end of the list containing it (if any).
+ *
+ * @param nd The node to test.
+ * @return bool true iff node is past the end of the list.
+ */
+static inline bool IntrusiveList_TestEnd(const IntrusiveList *ll, const IntrusiveNode *nd)
+{
+    return nd == &ll->node;
+}
+
+/**
+ * @brief Inserts a node after another one list.
+ *
+ * @param pos The node to insert the new node after.
+ * @param nd The new node.
+ */
+static inline void IntrusiveList_InsertAfter(IntrusiveNode *pos, IntrusiveNode *nd)
+{
+    // if pos is last & list is empty, ->next writes to first, etc.
+    pos->next->prev = nd;
+    nd->prev = pos;
+    nd->next = pos->next;
+    pos->next = nd;
+}
+
+/**
+ * @brief Erases a node.
+ *
+ * @param nd The node to erase.
+ */
+static inline void IntrusiveList_Erase(const IntrusiveNode *nd)
+{
+    nd->prev->next = nd->next;
+    nd->next->prev = nd->prev;
+}
+
+/**
+ * @brief Makes a list storage from a buffer, using each element's intrusive node field at offset 0.
+ *
+ * @param ll The intrusive list to create.
+ * @param buf The buffer to use.
+ * @param elem_size The size of each element.
+ * @param total_size The total size of the buffer.
+ *
+ * @pre @ref ll has not been initialized yet.
+ * @pre Each element must contain a @ref IntrusiveNode instance at offset 0, which is then used.
+ */
+static inline void IntrusiveList_CreateFromBuffer(IntrusiveList *ll, void *buf, size_t elemSize, size_t totalSize)
+{
+    IntrusiveList_Init(ll);
+    for (size_t pos = 0; pos < totalSize; pos += elemSize) {
+        IntrusiveList_InsertAfter(ll->last, (IntrusiveNode *)((char *)buf + pos));
+    }
+}