utcb handling helper routines for the thread library.

This is one of the steps we need in the process of providing a similar interface
for thread creation which can be found in the mainstream operating systems like
Linux.

conts/libl4thread/include/l4thread/idpool.h

@@ -0,0 +1,30 @@
+#ifndef __IDPOOL_H__
+#define __IDPOOL_H__
+
+#include <bit.h>
+#include <string.h>
+#include INC_GLUE(memory.h)
+
+struct id_pool {
+	int nwords;
+	int bitlimit;
+	u32 bitmap[];
+};
+
+/* Copy one id pool to another by calculating its size */
+static inline void id_pool_copy(struct id_pool *to, struct id_pool *from, int totalbits)
+{
+	int nwords = BITWISE_GETWORD(totalbits);
+
+	memcpy(to, from, nwords * SZ_WORD + sizeof(struct id_pool));
+}
+
+struct id_pool *id_pool_new_init(int mapsize);
+int id_new(struct id_pool *pool);
+int id_del(struct id_pool *pool, int id);
+int id_get(struct id_pool *pool, int id);
+int id_is_empty(struct id_pool *pool);
+int ids_new_contiguous(struct id_pool *pool, int numids);
+int ids_del_contiguous(struct id_pool *pool, int first, int numids);
+
+#endif /* __IDPOOL_H__ */