Merge branch 'remove_extlib' into scheduler-framework

src/lib/meson.build

@@ -82,6 +82,7 @@ libxce_src = [ gen_srcs[0],
                'window.c',
                'xceapi.c',
                'xcectx.c',
+               'xcelist.c',
                'xlist.c',
                'xstring.c',
                'zarray.c',

src/lib/xcelist.c

@@ -0,0 +1,82 @@
+#include <stdlib.h>
+#include <string.h>
+
+#include "xcelist.h"
+
+/*
+ * Intrusive circular doubly-linked list.
+ *
+ * The list head (`xcelist_t`) doubles as a sentinel: when the list is empty,
+ * both `forw` and `back` point back at the head. This keeps insertion and
+ * removal branch-free while allowing `list->forw` to be read directly as the
+ * first entry (as done by the autoscaler demand queue).
+ */
+
+xcelist_t* list_create(const char* name)
+{
+    xcelist_t* list = (xcelist_t*)calloc(1, sizeof(xcelist_t));
+    if (!list) {
+        return NULL;
+    }
+
+    /* empty list: head points at itself */
+    list->forw    = (xcelist_entry_t*)list;
+    list->back    = (xcelist_entry_t*)list;
+    list->numEnts = 0;
+
+    if (name) {
+        list->name = strdup(name);
+        if (!list->name) {
+            free(list);
+            return NULL;
+        }
+    }
+
+    return list;
+}
+
+void list_destroy(xcelist_t* list)
+{
+    if (!list) {
+        return;
+    }
+    free(list->name);
+    free(list);
+}
+
+void list_insert_entry_back(xcelist_t* list, xcelist_entry_t* entry)
+{
+    xcelist_entry_t* head;
+    xcelist_entry_t* last;
+
+    if (!list || !entry) {
+        return;
+    }
+
+    head = (xcelist_entry_t*)list;
+    last = head->back;
+
+    entry->forw = head;
+    entry->back = last;
+    last->forw  = entry;
+    head->back  = entry;
+
+    list->numEnts++;
+}
+
+void list_entry_remove(xcelist_t* list, xcelist_entry_t* entry)
+{
+    if (!list || !entry || entry == (xcelist_entry_t*)list) {
+        return;
+    }
+
+    entry->back->forw = entry->forw;
+    entry->forw->back = entry->back;
+
+    entry->forw = NULL;
+    entry->back = NULL;
+
+    if (list->numEnts > 0) {
+        list->numEnts--;
+    }
+}