1 files changed, 126 insertions, 0 deletions
diff --git a/lib/ngtcp2_pq.h b/lib/ngtcp2_pq.h
new file mode 100644
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--- /dev/null
+++ b/lib/ngtcp2_pq.h
@@ -0,0 +1,126 @@
+/*
+ * ngtcp2
+ *
+ * Copyright (c) 2017 ngtcp2 contributors
+ * Copyright (c) 2012 nghttp2 contributors
+ *
+ * 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.
+ */
+#ifndef NGTCP2_PQ_H
+#define NGTCP2_PQ_H
+
+#ifdef HAVE_CONFIG_H
+#  include <config.h>
+#endif /* HAVE_CONFIG_H */
+
+#include <ngtcp2/ngtcp2.h>
+
+#include "ngtcp2_mem.h"
+
+/* Implementation of priority queue */
+
+/* NGTCP2_PQ_BAD_INDEX is the priority queue index which indicates
+   that an entry is not queued.  Assigning this value to
+   ngtcp2_pq_entry.index can check that the entry is queued or not. */
+#define NGTCP2_PQ_BAD_INDEX SIZE_MAX
+
+typedef struct ngtcp2_pq_entry {
+  size_t index;
+} ngtcp2_pq_entry;
+
+/* "less" function, return nonzero if |lhs| is less than |rhs|. */
+typedef int (*ngtcp2_less)(const ngtcp2_pq_entry *lhs,
+                           const ngtcp2_pq_entry *rhs);
+
+typedef struct ngtcp2_pq {
+  /* The pointer to the pointer to the item stored */
+  ngtcp2_pq_entry **q;
+  /* Memory allocator */
+  const ngtcp2_mem *mem;
+  /* The number of items stored */
+  size_t length;
+  /* The maximum number of items this pq can store. This is
+     automatically extended when length is reached to this value. */
+  size_t capacity;
+  /* The less function between items */
+  ngtcp2_less less;
+} ngtcp2_pq;
+
+/*
+ * Initializes priority queue |pq| with compare function |cmp|.
+ */
+void ngtcp2_pq_init(ngtcp2_pq *pq, ngtcp2_less less, const ngtcp2_mem *mem);
+
+/*
+ * Deallocates any resources allocated for |pq|.  The stored items are
+ * not freed by this function.
+ */
+void ngtcp2_pq_free(ngtcp2_pq *pq);
+
+/*
+ * Adds |item| to the priority queue |pq|.
+ *
+ * This function returns 0 if it succeeds, or one of the following
+ * negative error codes:
+ *
+ * NGTCP2_ERR_NOMEM
+ *     Out of memory.
+ */
+int ngtcp2_pq_push(ngtcp2_pq *pq, ngtcp2_pq_entry *item);
+
+/*
+ * Returns item at the top of the queue |pq|.  It is undefined if the
+ * queue is empty.
+ */
+ngtcp2_pq_entry *ngtcp2_pq_top(ngtcp2_pq *pq);
+
+/*
+ * Pops item at the top of the queue |pq|. The popped item is not
+ * freed by this function.
+ */
+void ngtcp2_pq_pop(ngtcp2_pq *pq);
+
+/*
+ * Returns nonzero if the queue |pq| is empty.
+ */
+int ngtcp2_pq_empty(ngtcp2_pq *pq);
+
+/*
+ * Returns the number of items in the queue |pq|.
+ */
+size_t ngtcp2_pq_size(ngtcp2_pq *pq);
+
+typedef int (*ngtcp2_pq_item_cb)(ngtcp2_pq_entry *item, void *arg);
+
+/*
+ * Applys |fun| to each item in |pq|.  The |arg| is passed as arg
+ * parameter to callback function.  This function must not change the
+ * ordering key.  If the return value from callback is nonzero, this
+ * function returns 1 immediately without iterating remaining items.
+ * Otherwise this function returns 0.
+ */
+int ngtcp2_pq_each(ngtcp2_pq *pq, ngtcp2_pq_item_cb fun, void *arg);
+
+/*
+ * Removes |item| from priority queue.
+ */
+void ngtcp2_pq_remove(ngtcp2_pq *pq, ngtcp2_pq_entry *item);
+
+#endif /* NGTCP2_PQ_H */