1 files changed, 296 insertions, 0 deletions
diff --git a/src/plist.h b/src/plist.h
new file mode 100644
index 0000000..9328d27
--- /dev/null
+++ b/src/plist.h
@@ -0,0 +1,296 @@
+/*
+ * Copyright (c) 2017 Richard Braun.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ *
+ * Upstream site with license notes :
+ * http://git.sceen.net/rbraun/librbraun.git/
+ *
+ *
+ * Priority list.
+ *
+ * This container acts as a doubly-linked list sorted by priority in
+ * ascending order. All operations behave as with a regular linked list
+ * except insertion, which is O(k), k being the number of priorities
+ * among the entries.
+ */
+
+#ifndef _PLIST_H
+#define _PLIST_H
+
+#include <stdbool.h>
+
+#include "list.h"
+#include "macros.h"
+
+/*
+ * Priority list.
+ *
+ * The list member is used as the underlying regular linked list and
+ * contains all entries, sorted by priority in ascending order. The
+ * prio_list member contains exactly one entry for each priority
+ * present, also sorted by priority in ascending order. An entry
+ * on prio_list is the first entry in list for that priority.
+ * Here is a representation of a possible priority list :
+ *
+ *      list--|1|--|3|--|3|--|3|--|4|--|6|--|6|--|8|
+ *            | |  | |            | |  | |       |
+ * prio_list--+ +--+ +------------+ +--+ +-------+
+ *
+ */
+struct plist {
+    struct list list;
+    struct list prio_list;
+};
+
+/*
+ * Priority list node.
+ */
+struct plist_node {
+    unsigned int priority;
+    struct list node;
+    struct list prio_node;
+};
+
+/*
+ * Static priority list initializer.
+ */
+#define PLIST_INITIALIZER(plist) \
+    { LIST_INITIALIZER((plist).list), LIST_INITIALIZER((plist).prio_list) }
+
+/*
+ * Initialize a priority list.
+ */
+static inline void
+plist_init(struct plist *plist)
+{
+    list_init(&plist->list);
+    list_init(&plist->prio_list);
+}
+
+/*
+ * Initialize a priority list node.
+ */
+static inline void
+plist_node_init(struct plist_node *pnode, unsigned int priority)
+{
+    pnode->priority = priority;
+    list_node_init(&pnode->node);
+    list_node_init(&pnode->prio_node);
+}
+
+/*
+ * Return the priority associated with a node.
+ */
+static inline unsigned int
+plist_node_priority(const struct plist_node *pnode)
+{
+    return pnode->priority;
+}
+
+/*
+ * Update the priority of an already initialized node.
+ */
+static inline void
+plist_node_set_priority(struct plist_node *pnode, unsigned int priority)
+{
+    pnode->priority = priority;
+}
+
+/*
+ * Return true if pnode is in no priority lists.
+ */
+static inline bool
+plist_node_unlinked(const struct plist_node *pnode)
+{
+    return list_node_unlinked(&pnode->node);
+}
+
+/*
+ * Macro that evaluates to the address of the structure containing the
+ * given node based on the given type and member.
+ */
+#define plist_entry(pnode, type, member) structof(pnode, type, member)
+
+/*
+ * Return the first node of a priority list.
+ */
+static inline struct plist_node *
+plist_first(const struct plist *plist)
+{
+    return list_first_entry(&plist->list, struct plist_node, node);
+}
+
+/*
+ * Return the last node of a priority list.
+ */
+static inline struct plist_node *
+plist_last(const struct plist *plist)
+{
+    return list_last_entry(&plist->list, struct plist_node, node);
+}
+
+/*
+ * Return the node next to the given node.
+ */
+static inline struct plist_node *
+plist_next(const struct plist_node *pnode)
+{
+    return (struct plist_node *)list_next_entry(pnode, node);
+}
+
+/*
+ * Return the node previous to the given node.
+ */
+static inline struct plist_node *
+plist_prev(const struct plist_node *pnode)
+{
+    return (struct plist_node *)list_prev_entry(pnode, node);
+}
+
+/*
+ * Get the first entry of a priority list.
+ */
+#define plist_first_entry(plist, type, member) \
+    plist_entry(plist_first(plist), type, member)
+
+/*
+ * Get the last entry of a priority list.
+ */
+#define plist_last_entry(plist, type, member) \
+    plist_entry(plist_last(plist), type, member)
+
+/*
+ * Get the entry next to the given entry.
+ */
+#define plist_next_entry(entry, member) \
+    plist_entry(plist_next(&(entry)->member), typeof(*(entry)), member)
+
+/*
+ * Get the entry previous to the given entry.
+ */
+#define plist_prev_entry(entry, member) \
+    plist_entry(plist_prev(&(entry)->member), typeof(*(entry)), member)
+
+/*
+ * Return true if node is after the last or before the first node of
+ * a priority list.
+ */
+static inline bool
+plist_end(const struct plist *plist, const struct plist_node *pnode)
+{
+    return list_end(&plist->list, &pnode->node);
+}
+
+/*
+ * Return true if plist is empty.
+ */
+static inline bool
+plist_empty(const struct plist *plist)
+{
+    return list_empty(&plist->list);
+}
+
+/*
+ * Return true if plist contains exactly one node.
+ */
+static inline bool
+plist_singular(const struct plist *plist)
+{
+    return list_singular(&plist->list);
+}
+
+/*
+ * Add a node to a priority list.
+ *
+ * If the priority list already contains nodes with the same priority
+ * as the given node, it is inserted before them.
+ *
+ * The node must be initialized before calling this function.
+ */
+void plist_add(struct plist *plist, struct plist_node *pnode);
+
+/*
+ * Remove a node from a priority list.
+ *
+ * After completion, the node is stale.
+ */
+void plist_remove(struct plist *plist, struct plist_node *pnode);
+
+/*
+ * Forge a loop to process all nodes of a priority list.
+ *
+ * The node must not be altered during the loop.
+ */
+#define plist_for_each(plist, pnode)    \
+for (pnode = plist_first(plist);        \
+     !plist_end(plist, pnode);          \
+     pnode = plist_next(pnode))
+
+/*
+ * Forge a loop to process all nodes of a priority list.
+ */
+#define plist_for_each_safe(plist, pnode, tmp)              \
+for (pnode = plist_first(plist), tmp = plist_next(pnode);   \
+     !plist_end(plist, pnode);                              \
+     pnode = tmp, tmp = plist_next(pnode))
+
+/*
+ * Version of plist_for_each() that processes nodes backward.
+ */
+#define plist_for_each_reverse(plist, pnode)    \
+for (pnode = plist_last(plist);                 \
+     !plist_end(plist, pnode);                  \
+     pnode = plist_prev(pnode))
+
+/*
+ * Version of plist_for_each_safe() that processes nodes backward.
+ */
+#define plist_for_each_reverse_safe(plist, pnode, tmp)      \
+for (pnode = plist_last(plist), tmp = plist_prev(pnode);    \
+     !plist_end(plist, pnode);                              \
+     pnode = tmp, tmp = plist_prev(pnode))
+
+/*
+ * Forge a loop to process all entries of a priority list.
+ *
+ * The entry node must not be altered during the loop.
+ */
+#define plist_for_each_entry(plist, entry, member) \
+    list_for_each_entry(&(plist)->list, entry, member.node)
+
+/*
+ * Forge a loop to process all entries of a priority list.
+ */
+#define plist_for_each_entry_safe(plist, entry, tmp, member) \
+    list_for_each_entry_safe(&(plist)->list, entry, tmp, member.node)
+
+/*
+ * Version of plist_for_each_entry() that processes entries backward.
+ */
+#define plist_for_each_entry_reverse(plist, entry, member) \
+    list_for_each_entry_reverse(&(plist)->list, entry, member.node)
+
+/*
+ * Version of plist_for_each_entry_safe() that processes entries backward.
+ */
+#define plist_for_each_entry_reverse_safe(plist, entry, tmp, member) \
+    list_for_each_entry_reverse_safe(&(plist)->list, entry, tmp, member.node)
+
+#endif /* _PLIST_H */